Presentation type:
ERE – Energy, Resources and the Environment

EGU24-15525 | ECS | Orals | ERE5.3 | Highlight | ERE Division Outstanding Early Career Scientist Award Lecture

Fault Lines to Frontlines: Geomechanical Challenges of Sustainable Energy Transition 

Roberto Emanuele Rizzo, Derek Boswell Keir, Andreas Busch, Nathaniel Forbes Inskip, David Healy, Snorri Gudbrandsson, Luca De Siena, and Paola Vannucchi

The transition to sustainable energy systems introduces a complex landscape, wherein geothermal energy and carbon dioxide storage (CCS) play critical roles. These activities target geological formations that are always faulted and fractured. As the focus intensifies on alternative energy systems for decarbonisation, understanding these faulted rocks in the subsurface gains great importance. Fault and fracture systems can act not only as conduits for fluid flow but they can also be zones of mechanical weakness that may respond dynamically to fluid pressure changes due to natural geological processes or anthropogenic activities, such as CCS or geothermal extraction. This dual role of fault and fracture systems as pathways for fluid flow and as potential triggers for mechanical failure makes their study a cornerstone of sustainable subsurface resource management. The challenge lies in accurately characterising the permeability of these systems and estimating their mechanical behaviour under changing stress conditions. This is vital for ensuring the integrity and efficacy of operations like CCS and geothermal energy extraction, where even slight variations in fluid pressure can have significant implications. For instance, experiences from the fluid injection experiment for an enhanced geothermal system in Basel, Switzerland, and the In Salah CCS pilot site in Algeria highlight how minor changes in pore fluid pressures (as little as 10 MPa) can induce leakage and/or seismic activities. We highlight selected case studies from both active and prospective CCS and geothermal sites (in Svalbard and Mid-Ethiopian Ridge, respectively). These examples illustrate methodologies in fault stability analysis and geomechanical characterization, shedding light on the relationship between fluid flow, stress alterations, and rock mechanics in faulted and fractured formations. By coupling empirical data with modelling techniques, we present strategies to mitigate risks and enhance the efficiency of subsurface decarbonisation efforts.

How to cite: Rizzo, R. E., Keir, D. B., Busch, A., Forbes Inskip, N., Healy, D., Gudbrandsson, S., De Siena, L., and Vannucchi, P.: Fault Lines to Frontlines: Geomechanical Challenges of Sustainable Energy Transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15525, https://doi.org/10.5194/egusphere-egu24-15525, 2024.

ERE1 – Integrated studies

EGU24-79 | PICO | ERE1.1

Water supply risks for thermoelectric power plants considering climate change  

Zhenxing Zhang, Yao Wang, Laura De La Guardia, and Wei Dang

Water and energy are inextricably connected as water is needed for energy development and vice versa. This linkage is referred to as water-energy nexus, which highlights the need for integrated management and study of both resources. The nexus becomes even more complicated with climate change as both resources are greatly impacted by climate change. This study is aimed to assess the impact of climate change on water demand by thermoelectric power plants. The Integrated Environmental Control Model (IECM) and the Global Climate Model (GCM) are integrated to simulate water demand under future climate scenarios. The daily, monthly, and yearly water demand by selected thermoelectric power plants in Illinois are examined to explore the temporal patterns of climate change impact on water-energy nexus. Initial results showed that water use is more sensitive to shorter timescales. Compared with water withdrawal, water consumption is more sensitive to climate change.  This approach is also coupled with a hydrological model, specifically, a HSPF model, to assess the water supply risks to thermoelectric power plants in the future climate scenarios.

How to cite: Zhang, Z., Wang, Y., De La Guardia, L., and Dang, W.: Water supply risks for thermoelectric power plants considering climate change , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-79, https://doi.org/10.5194/egusphere-egu24-79, 2024.

EGU24-1106 | PICO | ERE1.1

A remote-sensing-based assessment of a city's urban environmental quality 

Srashti Singh, Anugya Shukla, and Kamal Jain

Unprecedental and unplanned urban sprawl poses a substantial challenge for cities in developing nations, detrimentally impacting the environmental quality of the urban landscape. The key environmental factors affected by urbanization must be vigilantly monitored to ensure sustainable urban development. Consequently, it is imperative to have a sustainable framework for a comprehensive and critical assessment of the environmental parameters that are affected because of urbanization. The aim of this research is to assess the environmental quality of a developing city in India – Bhopal and to quantify the environmental damage. The environmental quality is compared at 5-year time steps from 2000 to 2020 keeping 2000 as the benchmark year. The study employs satellite-based remote sensing data to extract all the parameters that are considered. The biophysical indicators (BI), include Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST), Particulate Matter concentration (PM2.5) and actual Evapotranspiration (ETa), and the census-related parameters include the Population Density (PD) and Built-up Volume (BV). The research assesses the relation between these parameters, followed by the quantification of an Environmental Quality Index (EQI) for the years 2005, 2010, 2015 and 2020 to investigate the city's environmental quality. The city's environmental quality is then categorized based on the EQI values in each year. The results reveal that there is a poorer quality of environment where the BV and PD is high, and vegetation cover is low, which also results into higher LST. PM2.5 was higher in the traffic congestion zones, industrialisation areas and major roads. The comprehensive findings indicate pronounced environmental degradation in specific areas characterized by dense urbanization, heavy traffic, industrial zones, and major highways. This study sheds light on the adverse environmental impacts of unplanned urbanization, providing valuable insights for policymakers and urban designers to enhance the quality of urban development and promote sustainability. Additionally, the research proposes strategies and policy interventions for addressing industrial and vehicular pollutants, emphasizing the crucial role of urban greening in elevating the overall urban environment.

How to cite: Singh, S., Shukla, A., and Jain, K.: A remote-sensing-based assessment of a city's urban environmental quality, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1106, https://doi.org/10.5194/egusphere-egu24-1106, 2024.

EGU24-1384 | PICO | ERE1.1

A Study on Vulnerability Maps for Marine Environmental impact Assessment 

Taeyun Kim, Junho Maeng, Eunchae Kim, Tae-sung Kim, and Moonjin Lee

In Korea, various development projects such as port construction, nearshore wind farms, tidal reclamation, and seawall construction have been taking place along the coast, however spatial information and vulnerability assessment methods for proper environmental impact assessment are lacking. In this study, we categorized four sectors (social environment, protected areas, habitats, and species) to create vulnerability maps on each that can be used for environmental impact assessment. The vulnerability map for the social environment includes spatial information on fisheries, aquaculture, coastal tourism, and port facilities, while the vulnerability map for protected areas is based on international protected areas, marine reserves, and environmental and fishery resource management areas. Habitat vulnerability map is based on data for tidal flats and wetlands, seagrass beds, stop-over sites of migratory birds, and marine protected species habitats. Finally, species vulnerability map was created spatial fish catches and marine bird tracking data. Vulnerability maps for each sector are based on the scores assigned to sector-specific indicators.

How to cite: Kim, T., Maeng, J., Kim, E., Kim, T., and Lee, M.: A Study on Vulnerability Maps for Marine Environmental impact Assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1384, https://doi.org/10.5194/egusphere-egu24-1384, 2024.

EGU24-1956 | ECS | PICO | ERE1.1

Global technical, economic and ecological performance of different solar photovoltaic modules  

Changkun Shao, Kun Yang, and Xinyao Zhang

Bifacial solar modules and solar trackers are experiencing worldwide rapid development, and they are proven to be effective in increase solar power generation. This study presents a comprehensive worldwide assessment on technical and economic potential of combination of mono or bifacial photovoltaic modules with different solar trackers based on a high-quality long-term solar radiation dataset and a physical model chain. Impact factors such as topography, land suitability, etc. were taken into consideration when evaluating electricity generation potential. Overall, bifacial photovoltaic modules can increase power generation and lower levelized tariffs globally. Solar trackers can increase the efficiency of PV panels, but reduce the total power generation due to lower land utilization. Fixed bifacial modules contributed the highest total global power generation of 2217 PWh and the lowest average global levelized cost of electricity of 3.6. The spatial distribution of the optimal PV module and solar tracker combination is also revealed by this study. Furthermore, there is a significant mismatch between energy generation and demand, despite the fact that total global electricity generation potential far exceeds total electricity demand. Countries with 70% of the total generation potential consume less than 20 % of the demand. Distributed PV may contribute to solving this problem. As for the environmental and ecological impact, the global carbon reduction and loss in ecosystems service values are 1205 million Mt and 3244 million dollars per year, respectively. The Sahara Desert and Western Asia, with high power generation potential and low ecological costs, serve to be hotspots for photovoltaic. This study providing guidance for selecting, sitting and deploying different solar modules combination, and emphasize the ecological and environmental impact of solar panels.

How to cite: Shao, C., Yang, K., and Zhang, X.: Global technical, economic and ecological performance of different solar photovoltaic modules , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1956, https://doi.org/10.5194/egusphere-egu24-1956, 2024.

With the green transition in Europe from fossil fuels to renewable energy, it will significantly change the demand for raw materials. The European Union’s new growth strategy focuses on sustainability. While doing so, the intent is to reduce the dependency on non-EU countries regarding the raw materials supply. Access to raw materials has been questioned by the European Commission for twenty years as it is foreseen as new “oil and gas”. The transition requires using carbon-free energy resources and electric vehicles which leads to a great need for raw materials that are used in the production of wind turbines, solar panels and batteries, etc. However, Europe is mostly dependent on non-EU countries which poses a risk of supply chain disruptions, as witnessed in the Covid-19 pandemic and the war in Ukraine.

In this study, silicon (Si) metal, one of the critical raw materials having high economic value, will be investigated in terms of its usage, substitution, supply, demand, and future strategies. Si metal is used in aluminum alloys, electronic, chemical, and photovoltaic applications. Green transition and autonomy in the mineral supply chain in Europe both require upscaling mining and supply from secondary materials/recycling of critical raw materials. However, there is almost no recycling of Si metal since it is mostly dispersive in metallic alloys and chemical applications. Thus, mining should be considered as the main activity for the security and sustainability of the Si metal supply chain. This implies that Europe will need to overcome several disadvantages such as no sufficient exploration of resources, public opposition to mining and complex permitting procedures, since it is not given the priority to produce their raw materials. Considering the disadvantages, it is estimated that the upscaling of the mining activities will take 10 to 15 years.

Today, China controls 76% of the Si metal global supply which increased by 10% since 2020 and USA shares 8 %, Brazil 7 % Norway 6 % of global production. Norway shares about 50% of the Si metal produced in Europe and there are high-purity quartz deposits distributed across the country. Furthermore, Norway possesses renewable and cheaper electricity, which is typically the most costly element in producing metals, in addition to its natural resources. The availability of affordable power will most likely become more crucial in the future as energy sources shift from hydrocarbons to green energy sources. Finland is assumed to have a high-quality reserve, while the exact quantities are unknown. In Greenland, although the purity is unknown, the reserves are thought to be substantial. Sweden is also known to have potential reserves of high-quality quartz. As a result, this study will elaborate on the potential leading role of northern countries in meeting Europe's Si metal needs in the path of green transition.

How to cite: Akyıldız, O.: The Importance of Silicon Metal on the Green Transition and the Role of Northern Countries in the Silicon Metal Market, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4042, https://doi.org/10.5194/egusphere-egu24-4042, 2024.

In the context of a circular economy, increasing the durability of existing infrastructure is of paramount importance. Roads are the lifelines of the modern economy, and it is imperative to increase their lifespan as part of sustainable growth. Most conventional roads are a mixture of rock aggregate and bitumen. The region where bitumen meets aggregate in any asphalt mix experiences a complex interaction between electrostatic, chemical, and mechanical forces resulting in the formation of an Interfacial Transition Zone (ITZ) (Zhu et al. 2017). More specifically, there is a complex behavior of materials that could result from three different types of interaction between the aggregates, fillers, and bitumen: i) physisorption ii) chemisorption iii) mechanical interlocking (Pasandín and Perez 2015).

The integrity of the ITZ is one of the crucial factors for the overall durability of any mixture containing aggregate and binding materials. Due to the complex interaction of different minerals, present in the rock aggregate, with the bituminous binder, this junction is considered a weak link that dictates the overall structural durability of the mixture (Zhu et al. 2021). Most of the studies concerning the ITZ are based on mechanical tests at the aggregate-bitumen contact and generally do not include mineralogical observations.

The present study focuses on the ITZ within laboratory-manufactured asphalt samples utilizing rock aggregate varieties typically used in surface courses in the Republic of Ireland. Structural and petrographic observations are made using a combination of digital microscopy and Raman spectroscopy. Early observations suggest that there is a strong control exerted by aggregate mineralogy on the formation of features within the ITZ, including the linear alignment of iron oxide particles in the bitumen. Iron-oxide particles could potentially create a zone of weakness in a stone-mix asphalt, especially where the key aggregate is greywacke.

References

  • Zhu et al. 2017; Identification of interfacial transition zone in asphalt concrete based on nano-scale metrology techniques, Materials and Design. 129, 91-102.
  • Pasadin and Perez, 2015; The influence of the mineral filler on the adhesion between aggregates and bitumen, International Journal of Adhesion and Adhesives.

 

How to cite: Chakraborty, T., Unitt, R., and Meere, P.: Investigation of the Interfacial Transition Zone (ITZ) in asphalt mastic and its effect on the integrity of the mix: A Raman hyperspectral approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4378, https://doi.org/10.5194/egusphere-egu24-4378, 2024.

The dissolution and diffusion process of hydrogen sulfide (H2S) in aqueous solutions are critical in the formation of many metal deposits and the stability of H2S hydrate also play an important role in natural gas exploitation and transportation due to the tendency of H2S to form hydrate at low temperature and high pressure, which can lead to pipeline blockage. In this study, the solubility and diffusion coefficient of H2S in water and brine as well as the stable conditions of H2S hydrates have been determined using fused silica capillary cell, high pressure optical cell, high pressure reactor, and Raman spectrometers.The details are as follows: (1) H2S solubility data in water were obtained at temperatures up to 573 K and pressures up to 100 MPa. These new data extend the predictable range of previous models. (2) The diffusion coefficients of H2S in water at 0.1–2 MPa and 273.1–373.1 K and in four brine solutions (0.62, 1, 2, and 3 mol•kg−1 NaCl) at 1 MPa and 273.1–373.1 K were determined. The results showed that the diffusion coefficient increased with the temperature and was inhibited by salinity. (3) The stability of H2S hydrate in water and brine including NaCl, KCl, MgCl2, NH4Cl, Na2SO4 and K2SO4 at the temperature range from 273.4 to 298.8 K, pressure ranging from 1.13 to 21.90 bar, and salinity from 3.4-20.0 wt.% were investigated. The results showed that the inhibitory effect of six electrolytes on H2S hydrate formation is in the order of MgCl2 > NH4Cl > NaCl > KCl > Na2SO4 = K2SO4.

How to cite: Jiang, L., Wu, C., Sun, J., and Lin, J.: Determination of the solubility, diffusion coefficient and hydrate stability of hydrogen sulfide in water and brine, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7342, https://doi.org/10.5194/egusphere-egu24-7342, 2024.

EGU24-9593 * | PICO | ERE1.1 | Highlight

Microbially mediated energy storage in the pedosphere  

Michael Harbottle, Holly Smith, Julia Kennedy, Devin Sapsford, Peter Cleall, Andrew Weightman, and Ugalde-Loo Carlos

Energy storage is vital to buffer intermittency in power supplies comprised largely or wholly of variable sources (e.g. wind, solar) at large and small scale. Present technologies and those in development (e.g. electrochemical cells) have disadvantages (e.g. cost, resource use, chemical hazard) whilst the capacity required is extremely large and widely distributed. Storage is needed for burgeoning off-grid small-scale infrastructure such as sensor networks as well as larger scale power sources. To address challenges with current technologies we demonstrate the ability of the pedosphere to store electrical energy and act as a natural, biogeochemical battery. The pedosphere, consisting of porous geomaterials such as soil and sediment, is an extensive potential energy repository covering much of the Earth and underpins most infrastructure or situations where power is generated or required. This pre-existing capacity has the potential to simplify energy storage and the installation and management of power generating or consuming infrastructure.

In this study the concept of such ‘geo-batteries’ is demonstrated. Controlled microbial synthesis of simple organic molecules in natural porous media (estuarine sediment) is shown, with this organic matter acting as an accessible form of energy storage. When combined with the employment of a microbial fuel cell to extract this energy electrically through degradation of the organic molecules, a battery is formed, with external control over energy input and output through switching of charging and discharging cycles.

This project received funding from the UK Engineering and Physical Sciences Research Council, grant no. EP/X018865/1.

How to cite: Harbottle, M., Smith, H., Kennedy, J., Sapsford, D., Cleall, P., Weightman, A., and Carlos, U.-L.: Microbially mediated energy storage in the pedosphere , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9593, https://doi.org/10.5194/egusphere-egu24-9593, 2024.

As global efforts towards achieving net-zero targets continue to grow, countries experiencing a surge in demand for renewable energy infrastructure may encounter competition due to uneven production capacities. Currently, European renewable energy infrastructure depends on limited suppliers and technologies, which have the potential to be diversified and robustified. This work aims to explore the potential supply chain transition of net-zero European renewable energy infrastructure and evaluate it in terms of environmental impacts, policy robustness, and economic costs. Based on results from scenario analysis, we find that the trade-offs always exist, i.e., sustainability, reliability, and affordability cannot be simultaneously achieved in a single scenario. Furthermore, the study emphasizes the close interaction of European renewable energy infrastructure with global capacity and market, indicating the need for a holistic approach in addressing the challenges of achieving a sustainable and resilient energy future.

How to cite: Cui, C.: Sustainable, Reliable, or Affordable: The Future European Renewable Energy Infrastructure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12941, https://doi.org/10.5194/egusphere-egu24-12941, 2024.

EGU24-14109 | ECS | PICO | ERE1.1

Joint Optimization of Lithology and Petrophysical Parameters in Athabasca Oil Sands Using Self-Attention Mechanism 

M Quamer Nasim, Paresh Nath Singha Roy, and Adway Mitra

Precisely determining lithology and petrophysical parameters, including core-calibrated porosity and water saturation, is crucial for reservoir characterization. The traditional method of manually interpreting well-log data is not only time-consuming but also prone to human errors. To address these challenges in identifying lithology and estimating petrophysical parameters in Athabasca Oil Sands region, this study introduces a novel solution using the AutoRegressive Vision Transformer (ARViT) model for accurate prediction. ARViT improves upon the ViT framework by integrating sequential dependencies into its output. The self-attention mechanism and auto-regression are key features that enable ARViT to systematically process data, capturing detailed spatial dependencies in well-log data. This empowers the model to discern subtle spatial and temporal relationships among various geophysical measurements. In essence, ARViT's incorporation of sequential information through its auto-regression mechanism on top of ViT enhances its ability to comprehensively model complex relationships within well-log data. In this study, a multitask learning approach is embraced to enhance the model's interpretability and efficiency. This methodology involves optimizing the model's performance across multiple tasks simultaneously. By doing so, the model gains a broader understanding of diverse tasks and benefits from shared knowledge and features across these tasks. This collaborative optimization contributes to a more robust and versatile model, ultimately improving its overall perflormance and interpretability. To evaluate the effectiveness of the ARViT model, we conducted a comprehensive series of experiments and comparative analyses, contrasting its performance with conventional artificial neural networks (ANN), Long Short-Term Memory (LSTM), and ViT models. Furthermore, to illustrate the versatility of ARViT, we apply Low-Rank Adaptation (LoRA) to a different, smaller dataset of well-log, showcasing its ability to adapt effectively to various geological contexts. LoRA becomes particularly crucial in this context, as it not only enhances the model's adaptability but also plays a vital role in reducing the number of trainable parameters. This reduction not only contributes to computational efficiency but is essential for preventing overfitting and ensuring optimal performance across different datasets. Our findings demonstrate the consistent superiority of ARViT over ANN, LSTM, and ViT in accurately estimating lithological and petrophysical parameters. This is highlighted by ARViT's remarkable Lithological Accuracy of 96.51%, surpassing the baseline ANN's 73.18%, LSTM's 89.80%, and ViT's 93.23%. The substantial reduction in Mean Squared Error (MSE) for porosity, decreasing from 0.0007 (ANN) to 0.0004 (ARViT), and water saturation, decreasing from 0.022 (ANN) to 0.005 (ARViT), further emphasizes ARViT's exceptional performance in providing precise and reliable predictions across various metrics. The application of LoRA yields notable enhancements in ARViT's performance metrics. Specifically, in terms of Lithology Accuracy, ARViT-LoRA showcases a significant improvement, soaring from 88.74% (ARViT-Scratch) to an impressive 97.22%. Additionally, the implementation of LoRA resulted in a significant reduction of GPU consumption by 25%. While lithology prediction has been a well-explored field, ARViT distinguishes itself through its exclusive combination of features, encompassing a self-attention mechanism, auto-regressive nature, and multitask approach, coupled with effective fine-tuning using LoRA. This unique combination positions ARViT as a valuable tool for addressing intricate challenges of lithology prediction and petrophysical parameter estimation.

How to cite: Nasim, M. Q., Singha Roy, P. N., and Mitra, A.: Joint Optimization of Lithology and Petrophysical Parameters in Athabasca Oil Sands Using Self-Attention Mechanism, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14109, https://doi.org/10.5194/egusphere-egu24-14109, 2024.

EGU24-17869 | PICO | ERE1.1 | Highlight

Enhancing the Ambition and Technical Feasibility of Delivering Nationally Determined Contributions to the Paris Agreement 

Joel Gill, Katherine Daniels, Dafydd Maidment, Mohammed Salih, and Lara Blythe

Delivering the goals of the Paris Agreement, including limiting global temperature rise to no more than 1.5°C requires the setting and implementation of ambitious yet viable Nationally Determined Contributions, or NDCs. Article 4 of the Paris Agreement establishes a responsibility on each party to ‘prepare, communicate and maintain’ successive NDCs, each more ambitious than the last. Parties are then encouraged to work at a domestic level to achieve their NDC objectives.

Based on an analysis of NDCs from eastern and northern Africa (including Ethiopia, Eritrea, Kenya, Malawi, Rwanda, Tanzania, Somalia, Sudan, and Uganda) here we outline steps that would (i) strengthen opportunities for scientific input in the development of NDCs, ensuring that the mitigation and adaptation pledges included are both comprehensive and scientifically feasible, and (ii) improve aligned implementation strategies, ensuring coherence with higher education and research and innovation, and a cross-governmental approach to addressing climate change.

A lack of engagement with appropriate expertise when developing NDCs may result in pledges that are not viable and/or the omission of feasible and impactful options. A lack of appropriate implementation planning, and policy coherence, may result in a skills shortage that hinders implementation of actions set out in NDCs and therefore the ability to deliver the mitigation and adaptation ambitions of the Paris Agreement. Collectively, the steps we propose would strengthen the NDC process, while also supporting global ambitions to improve education for sustainable development (Sustainable Development Goal 4.7), employment opportunities (Sustainable Development Goal 8.5, 8.6), and research capacity (Sustainable Development Goal 9.5).

How to cite: Gill, J., Daniels, K., Maidment, D., Salih, M., and Blythe, L.: Enhancing the Ambition and Technical Feasibility of Delivering Nationally Determined Contributions to the Paris Agreement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17869, https://doi.org/10.5194/egusphere-egu24-17869, 2024.

EGU24-17873 | ECS | PICO | ERE1.1

Nutrient removal in constructed wetlands: Especial emphasis on type of plantation method 

Mahak Jain, Balram Sharma, Sai Kiran Pilla, Partha Sarathi Ghosal, and Ashok Kumar Gupta

Constructed wetlands (CW) have emerged as sustainable and eco-friendly solutions for mitigating the impact of nutrient pollution in water bodies. Nutrient pollution, primarily caused by excess nitrogen and phosphorus, poses significant threats to aquatic ecosystems, leading to issues such as algal blooms, oxygen depletion, and impaired water quality. In response to these challenges, constructed wetlands have gained prominence as innovative systems capable of efficiently removing nutrients from wastewater and stormwater. These engineered ecosystems mimic the natural processes of wetlands to effectively treat wastewater. Among the key factors influencing the efficiency of nutrient removal, the choice of plantation method in CW stands out as a crucial aspect that demands closer scrutiny. As such, understanding the impact of different plantation methods on nutrient removal becomes paramount for optimizing the performance of constructed wetlands. This study focuses on elucidating the role of diverse vegetation strategies in enhancing the performance of these systems, with particular emphasis on nutrient uptake and transformation processes. Through a comprehensive review of existing literature, this research aims to identify and analyze the impact of various plantation techniques on nutrient removal efficiency. Factors such as plant species selection, plantation type i.e., single plant in a system (monoculture) or multiple vegetation in the system (polyculture) are examined to ascertain their influence on nitrogen and phosphorus removal rates. Polyculture improved TN and TP removal in horizontal subsurface CW by around 5%. However, a very high increment in treatment efficiency of both TN and TP was observed for vertical subsurface CW being more than 20%. Polyculture provided synergistic effect of various plant and microbial species for higher removal of nutrients from wastewater. Ultimately, the research aims to delineate the effect of plantation on performance of different CW in terms of mitigation of nutrient pollution in wastewater.

How to cite: Jain, M., Sharma, B., Pilla, S. K., Ghosal, P. S., and Gupta, A. K.: Nutrient removal in constructed wetlands: Especial emphasis on type of plantation method, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17873, https://doi.org/10.5194/egusphere-egu24-17873, 2024.

EGU24-19931 | ECS | PICO | ERE1.1

Sustainable Scale for Geosystem Services Use: Addressing the missing link in subsurface management 

Adithya Eswaran, Tine Compernolle, and Kris Piessens

Geosystem services as a concept allow for understanding the benefits that are gained from abiotic processes and structures that contribute to human welfare. These services are obtained from the diversity of the geosystem (of which the subsurface is a part) are often overlooked and undervalued. Intense anthropogenic utilization of these finite services, emphasizes the need for pre-emptive management of the subsurface. While the concept of geosystem services allows for capturing the plurality of the subsurface (in terms of different functions and services), it is often under-emphasized in subsurface management. The objective of this paper is to systematically review the existing approaches for the management of geosystem services in literature and contextualize the principle of sustainable scale in terms of a conceptual scheme for the subsurface. The systematic review's findings reveal a lack of comprehensive discussions on the management of geosystem services. Instead, the current discourse revolves around identifying various components that require management and emphasizing the necessity for active management. Although the articles propose recommendations for the management of geosystem services, they lack a set of operationalized principles that can be used by policymakers. To establish a conceptual scheme for the sustainable management of the services obtained from the services, the principle of sustainable scale as found in the literature of Ecological Economics was contextualized. The proposed conceptual scheme resulted in the following key aspects: (a) connects the subsurface characteristics (e.g. replenishment rates, different functions) and the nature of benefits (economic, environmental, and social) (b) provides the conceptual basis for defining the scale of subsurface utilization based on the type of service and its regeneration rate.

How to cite: Eswaran, A., Compernolle, T., and Piessens, K.: Sustainable Scale for Geosystem Services Use: Addressing the missing link in subsurface management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19931, https://doi.org/10.5194/egusphere-egu24-19931, 2024.

EGU24-20300 | ECS | PICO | ERE1.1

Effects of biogeochemical interactions between cementitious materials and sewage on the durability of wastewater treatment plant facilities 

Nedson Kashaija, Viktória Gável, Krett Gergely, Csaba Szabó, Erika Tóth, and Zsuzsanna Szabó-Krausz

Wastewater treatment plants (WWTPs) are critical environmental solutions for sanitation management in many cities and municipalities. The construction of these facilities uses cementitious materials (e.g., concretes) due to their low cost, high strength and excellent watertightness properties. However, the long-term performance of these materials in WWTPs is affected by deterioration influenced by the formation of new (secondary) cement minerals. These secondary minerals are formed as a result of biogeochemical interactions between cementitious materials and wastewater microbial communities. The literature shows a lack of consensus on the mechanisms involved in the biogeochemical mechanism of sewage and cementitious materials in WWTP facilities. As a result, many civil and water engineers are unaware of its adverse effects on the sustainability of WWTP facilities, and as a consequence, the operation of many WWTP facilities costs billions of dollars in repair and maintenance due to concrete failure. This study studies the possible processes of biogeochemical interactions between sewage and cementitious materials in WWTPs and their subsequent mineral alteration and formation.

An in-situ experiment exposed 48 cement specimens of ordinary Portland cement and calcium sulfoaluminate cement to the sewage pumping station and sand-trap structures. The research involves: (1) geochemical analysis (SEM and XRD) to study the change of cement materials, (2) engineering analysis to study their mechanical change and (3) microbiological investigations to explore the microbial communities involved in the biogeochemical interaction.

The preliminary results of the study: (a) change of color from light grey to a mixture of yellow and brown for cement pastes exposed in the sewage pumping station, whereas the samples from the sand-trap maintained their original grey color. (b) the appearance of secondary minerals such as gypsum (CaSO4.2H2O), ettringite (Ca6Al2(OH)12(SO4)3·26H2O), and thaumasite (Ca3Si(OH)6 (CO3) (SO4)12.H2O) which are characterized as expansive process causing several cracks in the concrete structures. (c) the main mechanism for the formation of these sulfur-related minerals (i.e., gypsum, ettringite, and thaumasite) involves sulfide adsorption and its subsequent oxidation to form biogenic H2SO4 which eventually attack the cement alkaline mineral phases such as portlandite (Ca(OH)2 and calcium silicate hydrate (C-S-H). Another biogeochemical mechanism for sewage-cement interaction observed in this work was the carbonation process, which resulted in the formation of calcite mineral in hydrated cement.

How to cite: Kashaija, N., Gável, V., Gergely, K., Szabó, C., Tóth, E., and Szabó-Krausz, Z.: Effects of biogeochemical interactions between cementitious materials and sewage on the durability of wastewater treatment plant facilities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20300, https://doi.org/10.5194/egusphere-egu24-20300, 2024.

EGU24-1232 | ECS | Posters on site | ERE1.2

Cost-effectiveness uncertainty may bias the decision of coal power transition in China 

Xizhe Yan and Dan Tong

Coal power transition always maintains a high complexity as the heterogeneities of characteristics such as technical attribute, economic lock-in, and environmental and health impact. Here, we explored the cost-effectiveness uncertainty brought by policy implementation disturbance of different phaseout and new-built strategies (i.e., the disruption of phaseout priority) of coal power based on a developed unit-level uncertainty assessment framework, and revealed the opportunity and risk of coal transition decision by employing preference analysis. We found that, the uncertainty of policy implementation might lead to potential delays in yielding the initial positive annual net benefits. For example, a delay of 6 years might occur when the prior phaseout practice is implemented. A certain level of risk remains in the implementation of the phaseout policy, as not all strategies can guarantee the achievement of positive cumulative net benefits from 2018-2060. Since the unit-level heterogeneities shape diverse orientation of decision making, the decision-making preferences would significantly alter the selection of coal transition strategy. While the uncertainty of policy implementation might lead to missed opportunities in identifying optimal strategy. Our results highlight the importance of minimizing the policy implementation disturbance, which helps mitigate the risk of negative benefits and strengthen the practicality of phaseout decision.

How to cite: Yan, X. and Tong, D.: Cost-effectiveness uncertainty may bias the decision of coal power transition in China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1232, https://doi.org/10.5194/egusphere-egu24-1232, 2024.

EGU24-1833 | ECS | Orals | ERE1.2 | Highlight

Solar park impacts on plant biomass and earthworm and nematode communities 

Luuk Scholten, Gerlinde De Deyn, and Ron de Goede

Solar parks are a rapidly expanding novel land use primarily to produce renewable energy. However, the aim is to make them multifunctional, and limit negative impacts on soils or even improve soil quality. Solar panels change the microclimate and cause shading below the panels, influencing plant growth and carbon and water inputs to the soil, with potential cascading effects on the soil biota. This research aimed to test the effect of solar panels on earthworm and nematode communities in 12 solar parks with contrasting designs across the Netherlands. Earthworm abundance and diversity, plant biomass and nematode abundance were measured between (gap) and below the solar panels. Nematode abundance was also measured at the highest and lowest edges of the panels. Plant biomass, nematode abundance and earthworm abundance were all significantly lower below the solar panels compared to in the gap between the panels. Nematode abundance at the highest and lowest edges showed intermediate numbers compared to the gap and below the panels. These results show that solar parks have a large impact on the soil biota and stress the need for guidelines for ecologically sound solar park designs to prevent soil damage.

How to cite: Scholten, L., De Deyn, G., and de Goede, R.: Solar park impacts on plant biomass and earthworm and nematode communities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1833, https://doi.org/10.5194/egusphere-egu24-1833, 2024.

EGU24-2933 | Orals | ERE1.2 | Highlight

Introducing the first ecovoltaic parks of Hungary: a reconciliation between solar development and nature conservation 

Csaba Tölgyesi, Botond Magyar, Kata Frei, Alida Anna Hábenczyus, Zoltán Bátori, and Róbert Gallé

Solar energy is the most rapidly growing renewable globally. However, ground-mounted solar panels have a high land requirement, leading to extensive, low-nature-value photovoltaic parks. This may be alleviated by considering ecological aspects during their planning, construction and mainetnance. The resulting ecovoltaic park can bring various benefits for the owners if ecosystem services related to the imporved ecological conditions are recognized and wisely utilized. A major step in developing ecovoltaic parks is the creation of a short but species-rich grassland ecosystem. There is little empirical evidence on how to achieve this; therefore, we set up an experimental sowing experiment in three formerly conventional photovoltaic parks located in the forest-steppe zone of Hungary. From the regional native grassland species pool, we selected short but competitive ones (two graminoids and 50 forbs that are often visited by pollinators), and sowed them in half of the parks (between panel rows) in October, 2022, while the other half was left as control. In 2023, we surveyed the vegetation of the sown and control parts of the parks and adjacent old-growth grasslands (as references), and found that total plant species richness and the species richness of grassland specialists increased compared to the control sites, but remained below the references. In contrast, the cumulative cover of grassland specialist species in the sown sites could reach the references. We also surveyed pollinator assemblages (hoverflies and wild bees), and found higher species richness and Shannon diversity in the sown parts then in the reference grasslands, while control parts of the parks showed intermediate values. This might have been caused by spillover from the sown parts, although flying pollinators might have also taken advantage of the permanent windshade among the panel rows of control parts, despite the low food supply compared to the reference grasslands. Our findings suggest a rapid improvement of plant and pollinator assemblages after sowing native seed mixtures in solar parks. The resulting high-nature-value grassland ecosystem can have many co-benefits for the owners, as (i) it requires lower management intensity due to the short vegetation, (ii) has the potential to offer high-quality forage for livestock or honey-bees, and (iii) lowers the widespread “not-in-my-backyard” syndrome of local inhabitants due to its attractive, flower-rich appearance.

How to cite: Tölgyesi, C., Magyar, B., Frei, K., Hábenczyus, A. A., Bátori, Z., and Gallé, R.: Introducing the first ecovoltaic parks of Hungary: a reconciliation between solar development and nature conservation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2933, https://doi.org/10.5194/egusphere-egu24-2933, 2024.

EGU24-4551 | Orals | ERE1.2

Remote sensing-based frameworks to quantify city-level carbon fluxes in urban green infrastructures 

Oz Kira, Julius Bamah, Alexander Muleta, and Shirley Bushner

The urban population is experiencing rapid growth, and it is estimated that around 90% of people will be living in cities by the year 2100. Given that urban areas are significant sources of greenhouse gas and pollutant emissions, and with the expectation that these urban areas will become even more densely populated, achieving sustainable urban living requires careful and well-informed urban planning for infrastructures capable of effectively mitigating these emissions. One commonly proposed approach to address this challenge is the implementation of urban green infrastructures, which are often regarded as net sinks for CO2. However, due to the diverse and varied land use within urban areas, our ability to precisely isolate and quantify their overall impact on the city's carbon balance is limited.

Our research aims to overcome this limitation by testing two distinct frameworks. The first integrates remote observations with local measurements to determine the carbon balance of green infrastructures at the city level, ultimately producing a detailed CO2 sequestration map of these infrastructures. The second utilizes satellite observations of solar-induced chlorophyll fluorescence, a signal emitted exclusively by vegetation, to estimate urban vegetation's city-wide carbon sequestration potential. Our findings demonstrate that these two frameworks provide valuable insights into the carbon sequestration capacity of green infrastructures.

The frameworks developed in this study offer a significant advancement in understanding the contribution of green infrastructures to the carbon budget of cities. This improved understanding can inform the planning of low carbon-emitting cities and aid in identifying green areas with limited—or even negative—net carbon uptake. Additionally, the results of this research may be instrumental for policymakers and city planners in developing more sustainable urban environments.

How to cite: Kira, O., Bamah, J., Muleta, A., and Bushner, S.: Remote sensing-based frameworks to quantify city-level carbon fluxes in urban green infrastructures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4551, https://doi.org/10.5194/egusphere-egu24-4551, 2024.

EGU24-4911 | Posters on site | ERE1.2

Electricity generation using biogas from food waste in Jakarta, Indonesia: Techno-economic and environmental impact analysis 

Jin-Kyu Park, Min-Jung Jung, Hui-Young Yun, and Kyung-Hui Wang

Food waste (FW) has a substantial environmental impact, contributing to 4.4 GtCO2 eq annually, equivalent to approximately 8% of total anthropogenic greenhouse gas emissions based on carbon footprints. Indonesia ranks as the world's second-largest food waste producer, estimated to generate 300 kg of food waste per capita per year. However, there is a scarcity of studies assessing the electricity generation potential and economic feasibility of biogas-to-electricity projects in Indonesia. This paper presents the recovery of biogas from food waste for electricity generation, aiming to determine its economic and environmental benefits for Jakarta, Indonesia. The food waste generation potential in Jakarta was estimated from 2024 to 2043, and the theoretical methane yield was calculated using Buswell's equation. The economic feasibility of anaerobic digestion projects was analyzed using various methods, including total life cycle cost, net present value, investment payback period, levelized cost of energy, and internal rate of return. Environmental impact assessment included air pollution (SO2, NOx, and PM10) and greenhouse gas (CO2 and CH4) emissions reduction. Methane yield from anaerobic digestion was determined to range from 315.9 to 616.5 × 106 m3/yr, with electricity generation potential between 721.5 and 1,407.9 Gigawatt-hours. Economic indicators demonstrated the viability of anaerobic digestion, with positive net present values. The net present value and levelized cost of energy for anaerobic digestion were $162.8 million and $0.095 per kilowatt-hour, respectively. Utilizing biogas from anaerobic digestion for electricity generation could displace 8.2 million tons of coal over the system's lifespan. This displacement would lead to reductions of 17.8 million tons of SO2, 13.9 million tons of NOx, 1.7 million tons of PM10, and 20.1 million tons of CO2 compared to coal combustion.

Acknowledgments

This research was supported by Particulate Matter Management Specialized Graduate Program through the Korea Environmental Industry & Technology Institute (KEITI) funded by the Ministry of Environment (MOE).

How to cite: Park, J.-K., Jung, M.-J., Yun, H.-Y., and Wang, K.-H.: Electricity generation using biogas from food waste in Jakarta, Indonesia: Techno-economic and environmental impact analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4911, https://doi.org/10.5194/egusphere-egu24-4911, 2024.

EGU24-5653 | ECS | Orals | ERE1.2

Inequality and driving factors in regional level energy-related CO2 emissions at a residential sector of Iran 

Behnam Ata, Parisa Pakrooh, and János Pénzes

An increasing amount of CO2 emissions from the household sector of Iran led us to analyze the inequality and understand the possible driving forces behind the CO2 emissions. The household sector in Iran contributes one of the largest sectors of CO2 emissions. The study of inequality provides information to policy‐makers to point policies in the right direction. By considering the differences in the socio‐economic factors of provinces, the study aims to analyze the inequality in CO2 emissions and different kinds of energy consumption, including oil, gas and electricity, for the household sector of Iran’s provinces between 2000 and 2019. Also, Household panel data of 28 provinces of Iran are employed by using both static and dynamic panel models for the years 2001 to 2019. This study investigates the relationship between CO2 emissions and the efficient factors in three major groups including energy, climate, and household socio-economic factors. the Theil index and Kaya factor, as a simple and common method, were considered to evaluate the inequality in both CO2 emissions and energy consumption, and determine the driving factor behind CO2 emissions. According to the results, inequality in oil and natural gas consumption were increasing, electricity was almost constant; however, CO2 emissions experienced a decreasing trend for the study period. The results of the Kaya factor indicate that the second factor, energy efficiency, with a 0.21 value was the main driving factor of inequalities in CO2 emissions. The empirical result of the static method showed a positive dependence of household CO2 emissions on Heating Degree Days (HDD), Cooling Degree Days (CDD), precipitation level, oil consumption, gas consumption, household income, size of household, and also building stocks. Also, removing the energy subsidy for fossil fuels due to substantial subsidy in fossil fuels in Iran or implementing a re-pricing energy policy can be a beneficial way to control carbon emissions from households within the provinces of the country.

Behnam Ata is funded by the Stipendium Hungaricum scholarship under the joint executive program between Hungary and Iran.

The study was elaborated under the research project TKP2021‐NKTA‐32 . 

How to cite: Ata, B., Pakrooh, P., and Pénzes, J.: Inequality and driving factors in regional level energy-related CO2 emissions at a residential sector of Iran, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5653, https://doi.org/10.5194/egusphere-egu24-5653, 2024.

EGU24-5919 | ECS | Posters on site | ERE1.2

Investigating the contribution of biogenic sinks and sources to Vienna’s CO2 budget using bottom-up modelling and tall-tower flux measurements 

Enrichetta Fasano, Carmen Schmid, Erwin Moldaschl, Merlin Mayer, Sebastian Konrad Braun, Francesco Vuolo, Peter Weiss, Helmut Schume, and Bradley Matthews

The importance of accurate monitoring of carbon dioxide (CO2) emissions from cities is underlined by the substantial urban contribution to global fossil fuel combustion. Typically, cities quantify emissions of CO2 using inventories and also use these models to design appropriate local mitigation policies and measures. However, inventories of individual cities can be uncertain (lack of appropriate activity data and emission factors, uncertainties in spatial downscaling) and furthermore often do not include estimates for the sector Land Use, Land-use Change and Forestry (LULUCF). While the relative, total contribution of LULUCF to a city’s annual CO2 balance may be assumed small, such an assumption should be verified. Furthermore, biogenic fluxes of photosynthesis and respiration may indeed be significant at higher temporal resolutions and omitting these fluxes can limit the conclusions drawn from comparisons of city CO2 inventories with estimates based on atmospheric CO2 observations.

The Vienna Urban Carbon Laboratory is currently investigating how monitoring of CO2 emissions in Austria’s capital city can be supported by a range of atmospheric measurement methods, including a tall-tower, urban application of eddy covariance. Despite the focus on atmospheric observations, the project is also investigating the contribution of biogenic fluxes to Vienna’s net CO2 budget. A LULUCF model of annual carbon stock changes has been developed following the IPCC guidelines using inter alia local forest inventory data and spatially-explicit data on land use and urban tree crown cover. Parrellel to this, work is underway to implement spatially- and temporally resolved simulations of vegetation CO2 fluxes using semi-empirical models of photosynthesis and respiration. Ultimately, integrating these results (together with bottom-up estimates of human respiration) will provide a more meaningful comparison between the local CO2 inventory with the fluxes derived from the eddy covariance measurements.

How to cite: Fasano, E., Schmid, C., Moldaschl, E., Mayer, M., Braun, S. K., Vuolo, F., Weiss, P., Schume, H., and Matthews, B.: Investigating the contribution of biogenic sinks and sources to Vienna’s CO2 budget using bottom-up modelling and tall-tower flux measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5919, https://doi.org/10.5194/egusphere-egu24-5919, 2024.

Highly accurate land cover (LC) information with fine spatial resolution serves as the cornerstone for reliable environmental insights, strategic land management, and ecological conservation. Yet, existing public LC products with 1-30m resolution exhibit considerable inconsistencies, particularly within complex terrains and fragmented habitats such as hill and gully regions, leading to uncertainties in various applications. In this context, our study innovatively targeted China's hilly and gully regions to develop an enhanced 10m resolution LC map for 2020, termed CLC-HG. The methodological advancement lied in fusing multiple LC products through accuracy evaluation, spatial consistency verification, object-oriented classification, and random forest classification. The research involved: (1) Strategic zoning of hilly and gully regions into five areas, selecting one or two representative validation regions within each; (2) Leveraging high-resolution imagery and 20000 field verification points to derive a 1m resolution land use dataset for validation regions, named GFLUCC, with 1m resolution and 95% accuracy; (3) Comprehensive validation of seven land use products spatial consistency and accuracy based on GFLUCC; (4) Filtering of layers based on spatial consistency, retaining regions with high and medium consistency; (5) Utilizing object-oriented classification and random forest classification, a higher-accuracy LC dataset was generated to replace the layers that were removed in the spatial consistency process; (6) Successful creation of CLC-HG, mirroring the accurate land use patterns of 2020. Our findings elucidated: (i) The superiority of WorldCover 10m in LC classification, contrasting with other products' regional inaccuracies; (ii) The influences of terrain complexity and human activity on accuracy, highlighting the precision in uniform areas versus the inaccuracy in complex regions; (iii) Substantial variations in spatial consistency across different terrains, with LP showing the weakest consistency; (iv) CLC-HG's remarkable performanced in identifying diverse LC types, boasting 85% overall accuracy; (v) Notable progress in classification accuracy with CLC-HG, uncovering the nuanced influences of land category complexity on consistency and human interventions on accuracy. This study breaks new ground by integrating multidimensional data and methodologies, contributing valuable insights for classification enhancements and more adept land resource management. The pioneering CLC-HGproduct holds significant potential to reduce uncertainties in global environmental change studies, ecosystem evaluations, and hazard assessments, marking an important step forward in remote sensing applications.

How to cite: Chen, L.: Multisource fusion for high-accuracy land cover mapping: A 10m resolution strategy in China's hill and gully regions , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9379, https://doi.org/10.5194/egusphere-egu24-9379, 2024.

EGU24-9583 | ECS | Orals | ERE1.2

Disentangling national carbon fluxes of African rainforest countries. 

William WM Verbiest, Corneille EN Ewango, Jean-Remy Makana, Simon Lewis, Marijn Bauters, Jean-François Bastin, Adeline Fayolle, Anaïs-Pasiphae Gorel, and Wannes Hubau

African tropical ecosystems possess great potential for nature-based solutions in mitigating fossil fuel emissions through absorbing and storing carbon in soil and vegetation. However, past studies mostly focused on pan-continental carbon balance quantification, often ignoring regional differences. Remarkably, few science-informed attempts have been made to refine carbon flux estimates at the national level within African rainforest countries. Yet, such refined estimates are essential to improve the quantification of Nationally Determined Contributions for the United Nations Framework Convention on Climate Change.

In this contribution, we present preliminary results on quantifying national carbon budgets for African rainforest countries by disentangling three major carbon fluxes for the period 2001-2015: (1) net carbon uptake in tropical savannas, woodlands, and forests, (2) carbon losses from land-use change, and (3) fossil fuel emissions. Carbon fluxes in intact forests are quantified using ground-based data1, while the carbon uptake by intact savannas and woodlands is based on Net Primary Productivity assessments estimated from remote sensing products2,3. Furthermore, carbon emissions from land-use change are estimated by analyzing various satellite images and related products providing data on land-use change4–6, soil and tree carbon stocks7–12, fire emissions3,13,14, and carbon recovery in regrowing forests15–18 in tropical Africa. Country-level fossil fuel emissions are taken from the Global Carbon Project database19 to complete the national carbon balances.

We reveal that most Central and East African rainforest countries acted as net carbon sinks between 2001 and 2015, while West African rainforest countries exhibited minimal net carbon loss. Overall, tropical ecosystems have played an important role in mitigating carbon emissions due to land-use change and fossil fuels in African rainforest countries, particularly in Congo Basin countries. Our insights into nation-level carbon fluxes will be crucial for informing African rainforest countries, guiding climate policies to stay on track to keep global warming well below 2°C.

References:

1. Hubau, W. et al. Nature 579, 80–87 (2020).
2. Running, S.W. et al. BioScience 54, 547-560 (2004).
3. Randerson, J.T. et al. (2018).
4. Hansen, M.C. et al. Science (1979) 342, 846–850 (2013).
5. Vancutsem, C. et al. Sci Adv 7, eabe1603 (2021).
6. Curtis, P.G. et al. Science (1979) 361, 1108–1111 (2018).
7. Simard, M. et al. Nat Geosci 12, 40–45 (2019).
8. Avitabile, V. et al. Glob Chang Biol 22, 1406–1420 (2016).
9. Zarin, D.J. et al. Glob Chang Biol 22, 1336–1347 (2016).
10. Saatchi, S.S. et al. Proc Natl Acad Sci USA 108, 9899–9904 (2011).
11. Baccini, A. et al. Nat Clim Chang 2, 182–185 (2012).
12. Poggio, L. et al. SOIL 7, 217–240 (2021).
13. Van Wees, D. et al. Geosci Model Dev 15, 8411–8437 (2022).
14. Di Giuseppe, F. et al. Atmos Chem Phys 18, 5359–5370 (2018).
15. Heinrich, V.H.A. et al. Nature 615, 436–442 (2023).
16. Deklerck, V. et al. Biol Conserv 233, 118–130 (2019).
17. Cook-Patton, S.C. et al. Nature 585, 545–550 (2020).
18. IPCC. 6 (2006).
19. Friedlingstein, P. et al. 14, 4811–4900 (2022).

How to cite: Verbiest, W. W., Ewango, C. E., Makana, J.-R., Lewis, S., Bauters, M., Bastin, J.-F., Fayolle, A., Gorel, A.-P., and Hubau, W.: Disentangling national carbon fluxes of African rainforest countries., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9583, https://doi.org/10.5194/egusphere-egu24-9583, 2024.

EGU24-10664 | ECS | Orals | ERE1.2

Multi-Dimensional Feasibility Assessment of the Deployment of Vortex-induced vibration Energy Harvester to utilize hidden hydro potential in European water and energy infrastructure 

Bjarnhéðinn Guðlaugsson, Matej Secnik, Ivana Stepanovic, Bethany Bronkema, Marko Hocevar, and David Finger

In recent years, there has been an increased interest in technologies such as Vortex-induced vibration energy harvesters (VIV-EH) concerning the potential to harvest and utilise the energy potential in oceans, rivers, channels and water pipelines. VIV-EH could be an ideal solution for energy generation through harvesting the kinetic energy from flow-induced vibration in open water systems such as rivers, lakes and lagoons, as well as closed water systems like water pipe systems in water and energy infrastructure. The energy generated could enable a self-powered sensor monitoring system and, therefore, replace the need for batteries or diesel generators to power the monitoring system, enhancing the water system's reliability. One of the applications explored for deploying VIV-EHs is installing into existing water pipelines to harness the flow vibration for energy generation. Assessing the feasibility of new energy technology such as VIV-EH is crucial to successfully implementing any technology into the pre-existing system. To fully determine feasibility requires information and inputs attained from assessing multiple cross-dimensional factors, which can provide information on the positive and negative economic, environmental and societal impacts and technological barriers or opportunities related to implementing this technology to any existing system infrastructure. To address this, an assessment framework is being developed, incorporating data and calculations from Life Cycle Assessment for calculating environmental impacts, MatLab for calculating the VIV-EHs key characteristics, and stakeholder engagement for assessing the selection of crucial evaluation metrics. The assessment tool will allow the user to carry out a multi-dimensional (Socio-Economic, Technical, Environmental) or single-dimension feasibility assessment concerning the integration of VIV-EHs into existing water infrastructure using a web-based tool. The application of the assessment framework provides critical informations such as VIV-EH's energy generation potential and role in the energy transition towards a cleaner and green energy system, which are relevant to designing a technology implementation strategy. The framework is applied, tested and used to evaluate the potential of VIV-EHs in various case studies: i) a geothermal district heating network in Reykjavik, Iceland; ii) a drinking water supply system in Ferlach, Austria, and iii) the MOSE flood protection in the Lagoon of Venice, Italy. Preliminary results suggest that the VIV-EH can reach capacities to supply sufficient energy – measured in watts – to power sensors for monitoring, maintenance and operation of water infrastructure. This continuous supply for monitoring networks can increase the resilience of water infrastructure and improve water resource utilisation, which is becoming more critical during climate change. The findings will be used to develop the assessment tool further and provide information that can help build a strategy for deploying VIV-EHs into water and energy infrastructure across Europe. The framework is tested on representative case studies across Europe but can potentially be applied in any energy system worldwide.

How to cite: Guðlaugsson, B., Secnik, M., Stepanovic, I., Bronkema, B., Hocevar, M., and Finger, D.: Multi-Dimensional Feasibility Assessment of the Deployment of Vortex-induced vibration Energy Harvester to utilize hidden hydro potential in European water and energy infrastructure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10664, https://doi.org/10.5194/egusphere-egu24-10664, 2024.

EGU24-11334 | Posters on site | ERE1.2

Transition towards low-carbon emissions: A Comparative Analysis between Western Macedonia (Greece) and Rhenish (Germany) 

Efthimios Tagaris, Apostolos Tranoulidis, Rafaella-Eleni P. Sotiropoulou, and Kostas Bithas

The transition away from fossil fuels involves management challenges since the socioeconomic prosperity of the affected areas should be assured. This study assesses the mechanisms, and the future planning of two European regions - Rhenish in Germany, and Western Macedonia in Greece – currently under decarbonization. The assessment is grounded in the application of the five EU - recommended tools, i.e., the governance tools, the sustainable employment and welfare support toolkit, the environmental rehabilitation and repurposing toolkit, the financial toolkit and the technology options toolkit. Rhenish region is targeting for lignite phase-out by 2038 whilst Western Macedonia has set a target for the completion of the transition away from lignite by 2028. The analysis carried out here has shown that both regions have adopted comprehensive strategic plans, delineated transition roadmaps, and established economic models. In particular, both regions have similar governance structures in place and have adopted comparable action plans for sustainable employment and welfare support. However, Western Macedonia faces some implementation challenges and delays in the sector of Reclamation and repurposing efforts. The financial structure of both regions is similar, with the EU and the state being the primary funding sources. Both regions are primarily considering technology options that prioritize the repurposing of power plants, the reduction of carbon emissions in energy-intensive industries, the utilization of hydrogen technologies, and non-electric carbon applications. The findings of this work will contribute to the development of viable strategies for coal transition in diverse national contexts. By thoroughly evaluating the experiences of these locations, this work aims to inform policymakers and stakeholders about effective approaches to navigate the challenges associated with decarbonization while ensuring sustained prosperity in affected areas.

How to cite: Tagaris, E., Tranoulidis, A., Sotiropoulou, R.-E. P., and Bithas, K.: Transition towards low-carbon emissions: A Comparative Analysis between Western Macedonia (Greece) and Rhenish (Germany), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11334, https://doi.org/10.5194/egusphere-egu24-11334, 2024.

EGU24-12276 | ECS | Orals | ERE1.2

The techno-environmental potential of offshore pumped hydro storage: A case study of the Dutch North Sea 

Inge Ossentjuk, Jan Wiegner, Robbert Nienhuis, Jasper Griffioen, Antonis Vakis, and Matteo Gazzani

Abstract

Energy storage systems (ESS) are required to overcome the challenges of large-scale integration of variable renewable energy. Specifically, offshore ESS can increase the utilisation of offshore transmission cables and reduce stress on the grid. Marine pumped hydro storage (PHS) is a promising technology in this domain [1]. This study focuses on the role of a subsea PHS system in offshore wind farms, taking the Dutch North Sea as a case study. This novel technology stores electricity on the seabed by pumping water to a reservoir subject to the hydrostatic pressure of the overlying seawater, and releases it by letting the water flow back through a set of turbines to a second reservoir at atmospheric pressure, thus utilising the change in potential energy associated with pressure difference.

Anthropogenic activities increasingly deploy marine environments as sites of operation. Besides traditional uses like fisheries, navigation, defence and
mining, the climate and biodiversity crises respectively call for the uptake of offshore renewable energy systems and biodiversity-enhancing structures such as artificial reefs. These activities affect the marine host ecosystems, though impacts can be both beneficial (providing artificial habitats) and detrimental (disturbing species) [2].

The European Topic Centre on Inland, Coastal and Marine waters highlights the importance of marine spatial planning and environmental impact assessment (EIA) methods in elucidating conflicts of interest between the development of offshore renewable energy and protection of the marine environment [3]. Though the environmental impacts of offshore renewable energy projects such as wind and even wave farms have been investigated and are safeguarded by EIA legislation, only few studies can be found on offshore energy storage. Research on offshore ESS mainly focuses on either the (life-cycle) environmental impacts of a technology, or on the technical and/or economic performance in terms of efficiency, feasibility or costs and benefits. The combination is lacking for specific technologies and areas, such as subsea PHS. Therefore, this study integrates a techno-economic modelling approach with EIA methodology with the objective of obtaining the techno-environmental potential of subsea PHS as a novel offshore energy storage system.

First, a literature review is conducted to compose a framework for the assessment of biological, chemical and physical impacts of offshore energy storage systems, consisting of a list of impact indicators and, if available, threshold values. Second, the framework is applied to a case study of subsea PHS in the Dutch North Sea. The technical potential, i.e., the optimal installed capacity from a technical point of view, is determined by modelling the Dutch planned offshore wind farms until 2030, allowing for installation of the storage technology to minimise curtailment of wind energy in the system. The model is formulated as a mixed-integer linear program. Third, the impact indicators are investigated for the resulting technology size and, taking threshold values into account, the environmental potential is determined. Last, trade-offs between technical performance and ecological effects are identified and discussed.

References

[1] Wang et al. A review of marine renewable energy storage. International Journal of Energy Research, 2019.
[2] Taormina et al. A review of methods and indicators used to evaluate the ecological modifications generated by artificial structures on marine ecosystems. Journal of Environmental Management, 2022.
[3] Galparsoro et al. Mapping potential environmental impacts of offshore renewable energy. European Topic Centre on Inland, Coastal and Marine waters, 2022.

How to cite: Ossentjuk, I., Wiegner, J., Nienhuis, R., Griffioen, J., Vakis, A., and Gazzani, M.: The techno-environmental potential of offshore pumped hydro storage: A case study of the Dutch North Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12276, https://doi.org/10.5194/egusphere-egu24-12276, 2024.

EGU24-13162 | ECS | Orals | ERE1.2

Calibration of the DayCent Model for Native Pastures in South-Eastern Queensland 

Zahrasadat Mirsafi, Ken Day, William Parton, Naoya Takeda, and David Rowlings

Soil organic carbon dynamics are strongly influenced by soil and climate conditions, as well as management practices including grazing and cropping. Over the past two decades, biogeochemical models have been widely used for analysing the effect of different environmental and management variables on soil carbon, including potential change under hypothetical future climate and management scenarios. The DayCent model, which is a daily implementation of the Century model, considers the impacts of soil texture, climate, historical vegetation cover, and land management practices, including crop type, fertilizer additions, and cultivation events on soil carbon dynamics.

In this study, we calibrate the DayCent model for two long-term (38-year) native pasture exclosures at one location in south-eastern Queensland. These sites have had similar management, being ungrazed and burnt or mown at the beginning of each pasture growing season but differ with respect to soil type (texture and depth) and species composition. One site is dominated by kangaroo grass (Themeda triandra), which represents the species composition prior to the introduction of tree clearing and grazing by cattle in the late 1800s. The other site is dominated by black spear grass (Heteropogon contortus) which has become the dominant species in the region since that time. To reflect the long-term species composition changes in the region, kangaroo grass crop parameters were used to run the model to equilibrium from year 1 AD to the year 1900 for both sites, and spear grass parameters were introduced in 1901 for the spear grass site.

The model calibration concentrated on the key ‘crop’ parameters governing potential production, root to shoot ratio, and plant carbon to nitrogen ratio. The calibrated DayCent model accounted for only 21 percent of the observed year-to-year variability in end-of-season above-ground biomass at the kangaroo grass site and 58%  at the spear grass site. The observed biomass production for the two sites was most strongly correlated with simulated evapotranspiration during the growing season (R2 = 0.43 and 0.58 for kangaroo grass and spear grass respectively) and we found a strong correlation between simulated and observed soil water content to a depth of 50 cm at both sites (R2 = 0.64 and 0.6 for kangaroo grass and speargrass respectively).

Whilst year-to-year variability was not well simulated, the long-term average production of each site is the main driver of soil carbon. For both sites, the model overestimated the average observed above-ground biomass at the end of the growing season by approximately 15 percent. By this time of year, the plants have flowered and lost biomass through the detachment of seeds and seed heads as well as some dead leaves. The timing of this detachment process is difficult to simulate in DayCent and it is therefore likely that DayCent simulated the annual biomass production quite closely. It remains to validate the DayCent simulations against similar long-term production data at a further six long-term study sites at this location and to evaluate how well DayCent simulates observed soil carbon across soil types, both under grazed and ungrazed conditions.

How to cite: Mirsafi, Z., Day, K., Parton, W., Takeda, N., and Rowlings, D.: Calibration of the DayCent Model for Native Pastures in South-Eastern Queensland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13162, https://doi.org/10.5194/egusphere-egu24-13162, 2024.

Against the backdrop of the rapid global rise of solar photovoltaic (PV) energy, its supply chain from manufacturing to installation has gradually exhibited dynamic spatial evolution, yet the spatiotemporal distribution of greenhouse gas emissions and mitigation throughout the entire PV industry chain has not received sufficient attention. The pathways to enhance the net mitigation benefits of PV through international collaboration across the entire industrial chain remains in its initial stage. This presentation will outline the author's systematic accounting of global supply chain carbon emissions and mitigation, combining spatiotemporal dynamic lifecycle assessments and scenario analyses. The analysis explored the spatiotemporal evolution of net greenhouse gas mitigation from 2009 to 2060 within the global PV industry. The study reveals that optimized collaboration between manufacturing and installation globally could increase the net mitigation effects of the entire industrial chain by 97.5 Gt carbon dioxide equivalent, equivalent to 1.9 times the global GHG emissions in 2020. This finding provides theoretical and empirical support for enhancing international strategic cooperation to enhance global greenhouse gas mitigation.

How to cite: Chen, S. and Lu, X.:  Greenhouse gas emissions and mitigation in the global solar photovoltaic industry chain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13733, https://doi.org/10.5194/egusphere-egu24-13733, 2024.

EGU24-13747 | Posters on site | ERE1.2

Optimal Transition Pathways Toward a Low-Carbon Energy System in China: a Data-Driven Optimization Prediction Model in Machine Learning. 

Xinxu Zhao, Li Zhang, Xutao Wang, Changyan Zhu, Kun Wang, Yu Ni, Jun Pan, Liming Yang, Yanlin Su, and Chenghang Zheng

The rapid expansion of renewable energy and the imperative for carbon reduction have prompted significant coal phase-outs. Coal is the largest contributor to energy-related carbon emissions globally, accounting for over one-third of the total. Coal-fired electric generating units (EGUs) play a significant role in these emissions, with over 5,000 units in China contributing to around 15% of global carbon emissions. These units, relatively young with an average age of less than 15 years, are facing challenges such as the absence of power purchase agreements, the prospect of early retirement, amid renewable energy growth, and ongoing retrofits for energy efficiency and carbon reduction. The transition pathway of the coal-fired power sector is crucial for its evolution and the integration of renewable energy. Hence, a data-driven optimization prediction model is introduced in this study, aiming to delineate an optimal transition pathway for the coal-fired power sector under different scenarios, guiding its evolution towards a low-carbon energy system.

The model comprises two modules: the phase-out module and the retrofit optimization prediction module. A unified unit-level database, encompassing operational data from over 5000 coal-fired EGUs in China, as well as techno-economic information associated with 21 types of carbon reduction retrofits, serves as the foundation for the most cost-effective pathway towards a low-carbon transition in the power sector. The phase-out module predicts the phase-out and remaining capacities, including the potential portion replaced by renewable energy. The phase-out determination involves assessing the cost of replacing coal-fired power with renewable power generation, along with considerations of the economics and carbon emissions associated with units under normal operation before retirement. This laterally furnishes valuable information for comprehending the potential capacity for renewable generation, ensuring that the transition pathways in the coal-fired sector are realized in a manner that safeguards the stability and reliability of the future power system. The optimization prediction model employs machine learning algorithms consisting of the predictor and the optimizer. The predictor provides estimates for overall carbon reduction potential (CRP) for the coal-fired power sector, even for the power sector, as well as near-term levelized costs of carbon emissions reduction (LCOC) and electricity (LCOE), approached from the unit-level perspective. The optimizer identifies portfolios that maximize carbon emission potential while minimizing costs. This study ultimately provides a comprehensive analysis of the low-carbon transition pathway for the primary source of emissions in the energy sector, namely the coal-fired power sector, conducted from both techno-economic and environmental (specifically carbon reduction) standpoints, employing an optimization prediction model.

How to cite: Zhao, X., Zhang, L., Wang, X., Zhu, C., Wang, K., Ni, Y., Pan, J., Yang, L., Su, Y., and Zheng, C.: Optimal Transition Pathways Toward a Low-Carbon Energy System in China: a Data-Driven Optimization Prediction Model in Machine Learning., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13747, https://doi.org/10.5194/egusphere-egu24-13747, 2024.

In Taiwan's rural areas, significant changes are underway in the once-predominant focus on traditional agriculture. The current landscape in rural areas is characterized not only by the presence of numerous factories but also by the increasing solar panels, driven by the ongoing transition to renewable energy sources. Despite numerous studies confirming the correlation between land use and temperature in urban areas, limited thermal research has been conducted in rural regions. Additionally, rural residents, particularly the elderly, are more sensitive to temperature variations.

The purpose of this study is to investigate whether the construction of iron rooftop factories and rooftop solar panel structures in rural environments results in significant differences in surface temperature and surrounding land use, thereby revealing the thermal impacts of these structures.Three coastal towns in central Taiwan were selected as the primary study area due to their higher density of solar panels and similar agricultural characteristics. Landsat 8 surface temperature data were utilized, with buffer zones established at 30-meter intervals from sample boundaries to explore variations in surface temperature and land use characteristics.

The findings reveal that rooftop solar panels and iron factories are predominantly surrounded by arid fields. As the distance from rooftop solar panels increases, the surface temperature gradually decreases, returning to ambient levels. However, no discernible changes in surface temperature were observed around iron rooftop factories. This study not only sheds light on the thermal impacts of these structures in rural environments but also points out the importance of land use control on thermal environments.

How to cite: Lee, Y.-J., Chung, M.-K., and Tseng, W.-L.: Coexisting Agriculture, Industry, and Energy in Rural Areas: Comparative Surrounding Surface Temperatures between Rooftop Solar Panels and Iron Rooftop in the Yunlin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13845, https://doi.org/10.5194/egusphere-egu24-13845, 2024.

EGU24-13941 | ECS | Posters on site | ERE1.2

GIS Assessment of Carbon Storage and Sequestration Impact Caused by Urban Development in Itaperuna-RJ, Brazil 

Igor Paz, Priscila Celebrini de Oliveira Campos, Norton Barros Felix, and Maria Esther Soares Marques

The changes in Land Use and Land Cover (LULC) have multifaceted impacts on sustainable development. Among the main ecosystem services acting on the environment, the Carbon Storage and Sequestration consists of the process of removing carbon from the atmosphere and its subsequent incorporation or storage in the form of biomass. Therefore, its understanding and modeling allow the control and instrumentalization of the biological absorption of carbon by the soil and, consequently, the reduction of the amount of greenhouse gases (GHG) in the atmosphere. To unravel this intricate ecosystem service, this study employs the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) methodology, specifically the Carbon Storage and Sequestration (CSS) model, within the municipality of Itaperuna in the northwest of the state of Rio de Janeiro (RJ), Brazil. This model estimates the amount of carbon stored in an area, calculates the variations that have occurred, and predicts future storage in the same region. It does so by analyzing land use and land cover, estimating carbon sequestration alterations between different scenarios, and assessing their monetary worth. To undertake this analysis effectively, three key pieces of information are essential: delineation of two LULC scenarios (e.g., 2015 and 2020), carbon content across various LULC classes, and the Social Cost of Carbon (SCC), which evaluates potential socioeconomic repercussions due to climate change for each ton of carbon emitted. This investigation aims not only to comprehend the dynamics of land use and land cover alterations in a medium-sized city within this region but also to estimate changes in carbon stocks and sequestration resulting from LULC transformations. The study further intends to quantify the financial implications of these alterations through the application of SCC.

How to cite: Paz, I., Celebrini de Oliveira Campos, P., Barros Felix, N., and Soares Marques, M. E.: GIS Assessment of Carbon Storage and Sequestration Impact Caused by Urban Development in Itaperuna-RJ, Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13941, https://doi.org/10.5194/egusphere-egu24-13941, 2024.

The quantification of carbon sequestration in Urban Green Spaces (UGSs) is challenging due to their unique characteristics such as the fragmentation of green spaces, human-influenced species selection, and varying management practices. IPCC guidelines recommend calculating carbon sequestration in UGSs per individual tree or crown cover area. Although crown cover area-based estimation is commonly used in national greenhouse gas inventories, research on the growth rate based on crown cover area (CRW) and the effects of varying sampling methodologies is limited. This research aimed to calculate CRW [ton C (ha crown cover)-1 yr-1] in South Korea using two distinct sampling methods. MethodSS (MSS; Systematic Sampling Method) divided urban areas into 500m x 500m grids and selected a 5% sample (1,603 grids) randomly. Within each grid, three sites were chosen and vegetation at three points was surveyed. For analysis, only points with trees excluding shrubs were included. MethodCS (MCS; Categorized Sampling Method) divided UGSs into three categories: street trees, urban parks, and others. For each category, 48 sites with three plots each were selected. In the street trees category, a plot consisted of 20 trees, while in urban parks and others, a plot was defined as a 20 x 20 m area. At each plot, species, diameter at breast height (DBH), height, and crown width of all trees were measured. For the derivation of CRW, a total of 8,037 and 5,733 trees were used in MSS and MCS, respectively. CRW was calculated in four steps: 1) The carbon storage of individual trees (Ct1) was calculated using allometric equations and the carbon fraction. 2) The carbon storage from one year prior (Ct2) was estimated based on the annual DBH growth rate (cm yr-1). 3) The annual carbon accumulation (kg C tree-1 yr-1) was calculated as the difference between Ct1 and Ct2. 4) CRW was calculated by dividing the total annual carbon accumulation by the total crown cover area of the surveyed trees. As a result, The study revealed a notable difference in CRW between MSS and MCS. MSS reported CRW of 0.23 ton C ha-1 yr-1, while MCS presented 0.30 ton C ha-1 yr-1. When categorized by land use, CRW was found to be highest in urban parks followed by others and street trees. In MSS, the diverse sample locations resulted in a wider range of DBH values, including many large-sized trees (DBH ≥ 70 cm). The lower CRW estimates in MSS were primarily due to the assumption that large-sized trees had zero annual carbon sequestration following the IPCC guidelines. This led to a higher inclusion of large-sized trees in MSS, resulting in lower CRW values. Also, there were significant differences in species distribution, tree sizes (DBH), and CRW, depending on the sampling methodology. These variances are primarily due to the unique characteristics of UGSs. The study highlights the necessity for further research into more representative sampling methodologies for estimating carbon sequestration in UGSs.

How to cite: Lee, J., Jo, H., Kim, W., and Son, Y.: Annual Carbon Sequestration Per Crown Cover Area of Urban Green Spaces in  South Korea: Comparative Analysis Using Different Sampling Methodologies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14214, https://doi.org/10.5194/egusphere-egu24-14214, 2024.

EGU24-18737 | Posters on site | ERE1.2

Impact of recent forest protection on deadwood carbon stocks 

Katarina Merganicova, Renata Nowinska, Jan Merganic, and Lech Kaczmarek

The reduction of carbon dioxide levels in the atmosphere is one of the most pressing issues in the context of global warming. Forest ecosystems play a crucial role in carbon cycling due to their ability to store significant amounts of carbon in plant biomass, deadwood and soil. Research on deadwood has usually focused on the analysis of the current state without considering the history of forest stands. However, a recent trend in many European countries is to increase the area and number of protected areas, often encompassing previously managed forests. Such changes in forest management affect the abundance and character of deadwood, and thus and need to be considered in the analysis of its carbon storage capacity.

The forests of Wielkopolski National Park in Poland are an excellent subject for such research. Until the end of the 18th century, they were owned by various landowners, leading to a highly diversified forest management driven by immediate needs of owners. In 1931, the first reserve, where logging was discontinued, was established. The current strict protection areas were mostly designated in 1957 when the park was legally established. Currently, strict protection mainly applies to habitats of oak-hornbeam forests Galio sylvatici-Carpinetum betuli, with other communities represented to a lesser extent.

The assessment of deadwood carbon stock (DWCstock) was performed using the data from the field survey conducted between 2017 and 2018. Deadwood was inventoried at 98 circular plots (0.04 ha) located inside 12 strictly protected areas. We distinguished five deadwood categories: standing snags, logs, stumps, branches, and twigs, and 5 decay classes. All dead trees and their parts with a minimum top diameter of 3 cm were measured. The small diameter threshold was selected due to the abundant presence of shrubs that ocurrred during the 'renaturalization' of forest ecosystems. From the measured dimensions we derived DWCstock using species- and decay-specific volume equations, wood density and carbon fraction values. The data were stored in a relational database and further processed and statistically analysed in the R environment. 

The analysis showed a high variability of DWCstock between plots (from 0.19 to 92.43tC/ha, mean 15.03tC/ha). Almost 50% of the total DWCstock was assigned the third decay stage, while 10 and 5% of DWCstock occurred in the first and last decay stage, respectively. This indicates a substantial accumulation of the deadwood after the abandonement of forest management. In 60% of cases, the dominant species of deadwood did not coincide with the dominant species of the currently living trees suggesting the changes in species composition of forest ecosystems over time. The results show deadwood can be considered as a long-term memory of forest dynamics. The work highlights the need to use multiple data sources for a better understanding of ecosystem development.

How to cite: Merganicova, K., Nowinska, R., Merganic, J., and Kaczmarek, L.: Impact of recent forest protection on deadwood carbon stocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18737, https://doi.org/10.5194/egusphere-egu24-18737, 2024.

China and India, two of the world's leading carbon emitters, have pledged to achieve carbon neutrality by mid-century in alignment with the Paris Agreement. Central to this ambition is the electrification of their economies, and both nations have made significant strides in recent years. Yet, a thorough cost-benefit analysis of their energy transition progress and future energy transition pathways remains lacking. Here we adopt nine comprehensive models to assess the region-specific co-benefits related to carbon emission, air pollution, health and employment of energy transition in the power sector in China and India from 2015-2020 and further explore their most cost-effective pathways towards 1.5°C and 2°C scenarios in 2030-2050. We find that although the emissions contributed by the power sector in China and India from 2015 to 2020 resulted in more than 10,000 PM2.5 attributable deaths in 2020, the economic benefit of job creation of new installation of renewable power in 2020 was 68 (95% CI: 56-93) times and 6 (95% CI: 5-7) times than the monetary of health loss. Under the SSP1_RCP2.6 scenario, it will ultimately achieve the largest benefit (monetary health co-benefits) to cost (carbon mitigation cost) ratio for both countries in 2050, and India (14.6 (95% CI: 12.7-16.1) will obtain a larger ratio than that of China (4.1 (95% CI: 3.3-4.7)). We recommend both nations deepen their commitment to power sector transition, prioritizing low-carbon fuels and expanding education and skill training to support the emerging new energy economy.

How to cite: Lu, C.: Co-benefits and cost-benefit analysis of energy transition in the power sector in China and India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20459, https://doi.org/10.5194/egusphere-egu24-20459, 2024.

EGU24-20934 | Posters on site | ERE1.2 | Highlight

Grassland establishment in solar parks on former arable land - spontaneous succession and first findings of a highly divers seed-based approach 

Sandra Dullau, Maren Helen Meyer, Pascal Scholz, and Sabine Tischew

In recent years, landscapes in many countries have been transformed by efforts to fight global warming, specifically the shift towards renewable energies. Photovoltaics is one of the key technologies for reducing greenhouse gas emissions and achieving climate neutrality for Europe by 2050, which has led to the promotion of solar parks. Due to the ambitious goals for the expansion of photovoltaics, a multiple of the area used so far will be built on with solar parks. These parks are often built on arable land, can span up to several hundred hectares, and grassland vegetation is usually created between and under the panels. In most cases, this is done by spontaneous revegetation or by seeding species-poor mixtures dominated by grasses.

In a case study of 12 spontaneously planted solar parks in a structurally poor agricultural landscape in central Germany, we found an average of 90 vascular plant species. However, the number of target grassland species is only one third and the majority are ruderal species. A comparison of the three zones showed that there were the same number of target grassland species in the area between the panels and without panels, but significantly fewer under the panels. Surprisingly, the coverage of target grassland species was highest between the panels.

Establishing grasslands using highly divers native seed mixtures can significantly enhance target species richness. This finding has already been well documented by grassland restoration research. However, it has not yet been proven for solar parks with their special characteristics, such as small-scale modified site conditions. In two solar parks on ex-arable land, we seeded a site adapted seed mixture with high percentage of forb seeds (39 species, including 3 grasses). In the first year after sowing, the establishment success of the sown species in the areas between the PV panels were recorded. The establishment rate was 25-30 % in the unshaded sections, increased significantly in the partially shaded sections and fell sharply with increasing shade. The low establishment rate is probably related to the significantly below-average rainfall in 2021, while the partially shaded sections provided better establishment conditions due to higher soil moisture. Heavy shading hindered the establishment of light-demanding grassland species. An increasing establishment rate is expected in the further vegetation development and must continue to be monitored.

How to cite: Dullau, S., Meyer, M. H., Scholz, P., and Tischew, S.: Grassland establishment in solar parks on former arable land - spontaneous succession and first findings of a highly divers seed-based approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20934, https://doi.org/10.5194/egusphere-egu24-20934, 2024.

EGU24-21320 | ECS | Posters on site | ERE1.2

Variability of litter carbon stocks in Croatia 

Doroteja Bitunjac, Maša Zorana Ostrogović Sever, Darko Bakšić, Mislav Anić, and Hrvoje Marjanović

Litter stores around 5% of total carbon (C) stocks in the World's forests (Pan et al. 2011) and is one of five forest ecosystem C pools in national greenhouse gas (GHG) inventory reports, for which reporting is mandatory. Litter is known for its high spatial heterogeneity at different scales. Litter mass, and therefore its C stock, varies with respect to climate region, forest type, and various site and stand characteristics. Litter in the context of GHG reporting in Croatia corresponds to the forest floor (undecomposed leaf organic layer – OL, and fragmented and humified organic layer – OFH), while emissions and removals from the Forest land category, which includes the Litter pool, are stratified into Broadleaves and Conifers. Although a relatively small country in Europe, the biogeographical diversity of Croatia is high, which leads to the question if the existing stratification for the litter should be refined. We tested the hypothesis that litter C stocks within specific tree species groups (Broadleaves and Conifers) differ between biogeographical regions (BGR).

From available national data sources, we compiled a database on litter, soil and forest stand variables at 276 plots distributed across three BGRs in Croatia: Alpine, Continental and Mediterranean. Litter data includes height, dry mass, C stock and C/N. Soil data includes soil organic C (top 30 cm), soil texture and bulk density. Stand variables include main tree species, stand basal area and tree density. Additionally, the database includes information on mean annual temperature (MAT), mean annual precipitation (MAP) and elevation at the plot level. Data were analysed at different scales regarding three BGR and two tree species groups (Broadleaves and Conifers).

Litter C stocks showed high variability (CV>30%) at the regional scale, with the Mediterranean BGR having the highest variability (CV of 43%). When looking at the specific tree species group, coniferous forests in Mediterranean BGR have the highest averaged litter C stocks (8.13 tC ha-1), while the broadleaf forests in Continental BGR have the lowest averaged litter C stocks (4.37 tC ha-1). Litter C stocks significantly differ between Alpine and Mediterranean BGR in coniferous forests, while in broadleaf forests significant difference in litter C stocks was observed between Alpine and Continental BGR. Our results indicate that the stratification of the Litter with respect to BGRs may improve the accuracy of the national carbon inventory.

How to cite: Bitunjac, D., Ostrogović Sever, M. Z., Bakšić, D., Anić, M., and Marjanović, H.: Variability of litter carbon stocks in Croatia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21320, https://doi.org/10.5194/egusphere-egu24-21320, 2024.

EGU24-21950 | ECS | Posters on site | ERE1.2

Intercomparison of soil organic carbon stocks measured from conventional and in situ sampling techniques at different spatial scales 

Macdara O'Neill, Marcos Alves, Andrew Manderson, Roberta Macdonald, and Petros Georgiadis

Soil organic carbon (SOC) is a key property of soil quality in arable soils and can play a central role in the voluntary carbon credit market by improving soil health, future food security and mitigating against climate change. The adoption of regenerative agricultural practices are considered one solution to achieve increases in SOC sequestration rates. However, the spatiotemporal dynamics of SOC mean the changes in SOC attributed to management practices are often difficult to detect across different spatial scales and over short temporal periods. Thus, rapid, cost-effective methods for quantifying carbon are sought by key stakeholders in both academia and industry for accurate accounting of SOC stocks. A field trial experiment was conducted in 2023 on five arable fields in Denmark to compare SOC stocks measured between: (i) the conventional sampling method and (ii) a portable, handheld visible near infrared (NIR) spectrometer. The conventional sampling method used a hydraulic corer to extract soil in each field (n=9) split into three depth increments (0-15, 15-30 and 30-60 cm). The samples were analysed for %SOC by the dumas dry combustion method whilst bulk density was measured volumetrically from the intact core upon extraction. For the spectroscopy method, soil was first extracted using a handheld auger (0-30 cm) which was subsequently homogenised and soil properties (%SOC, %Clay content and bulk density) were measured in situ by the scanner. The SOC concentration of these in situ soil samples were also measured by dry combustion analysis. We found differences in cumulative SOC stocks between the conventional and NIR methods attributed to variation in how SOC concentration was measured (directly vs. dry combustion) and less so to variation in bulk density. Clay contents were also similar between the conventional sampled soils and NIR soils, whilst the SOC concentrations measured by dry combustion were similar for both conventional and NIR soils. Overall, the results highlight that portable vis-NIR spectroscopy could be a scalable solution for monitoring SOC stocks in arable soils.

How to cite: O'Neill, M., Alves, M., Manderson, A., Macdonald, R., and Georgiadis, P.: Intercomparison of soil organic carbon stocks measured from conventional and in situ sampling techniques at different spatial scales, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21950, https://doi.org/10.5194/egusphere-egu24-21950, 2024.

EGU24-22105 | ECS | Orals | ERE1.2

Optimized renewable energy production for a low-carbon future to mitigate climate change and associated health impacts 

Victoria Gallardo, Pedro Jiménez-Guerrero, and Sonia Jerez

The transition towards a decarbonized electricity system, based on renewable energies, is urgently needed to achieve the so-called carbon neutrality and help mitigating climate change, among other reasons. At the same time, there is a need for electricity production from renewable energies to be stable in time, or to follow the demand, without substantial fluctuations. The open-access step-wise model called CLIMAX exploits the fact that wind and solar photovoltaic (PV) power present a certain degree of spatio-temporal complementarity in order to reduce the volatility of their combined production at its minimum. In a previous study, CLIMAX was used to identify optimum deployments of PV and wind power facilities across five European domains (Jerez et al., 2023). Here, using these optimum capacity density scenarios, the installed capacity per European country for the period 2012-2020 as reported in IRENA (2020), and ERA5 reanalysis data for the same period, are used to compute capacity factors, and the wind-plus-solar electricity production is estimated and compared to that from a BASE scenario with a homogeneous spatial distribution of installations. Results show that the optimization of the spatial distribution of the wind-plus-solar installed capacities does not only enhance the stability of the energy production in time, but also in terms of mean values (i.e. efficiency). More precisely, an average improvement in the energy production of +47.5 TW·h per year, integrated over Europe, is obtained as compared to BASE. Consequently, pollutant emissions from thermal power plants could have been reduced if electricity would have been produced from these renewable sources. In this work, this reduction is estimated and, in a last step, the potential reduction of human deaths related to air pollution is also evaluated. Results encourage further efforts towards a low-carbon energy future.

 

REFERENCES:

Jerez, S., Barriopedro, D., García-López, A., Lorente-Plazas, R., Somoza, A. M., Turco, M., et al. (2023). An action-oriented approach to make the most of the wind and solar power complementarity. Earth's Future, 11, e2022EF003332. https://doi.org/10.1029/2022EF003332.

IRENA. (2020). Renewable capacity statistics 2020. International Renewable Energy Agency (IRENA).

How to cite: Gallardo, V., Jiménez-Guerrero, P., and Jerez, S.: Optimized renewable energy production for a low-carbon future to mitigate climate change and associated health impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22105, https://doi.org/10.5194/egusphere-egu24-22105, 2024.

EGU24-22175 | Orals | ERE1.2 | Highlight

Degraded pasturelands for sustainable biorenewables production: an ecological approach 

Maíra Padgurschi, Daniele de Souza Henzler, Gabriel Palma Petrielli, and Thayse A. D. Hernandes

Worldwide changes in the land use and climate are the main drivers that have triggered a decline in both biological and cultural diversities, and the degradation of ecosystems. In countries like Brazil, deforestation is the main source of greenhouse gas emissions, and it is increased, in some cases, by the degradation. As response to those challenges, degraded areas have emerged as a promising option for cultivating biomass to produce biorenewables, aligning with the concept of a 'green transition'. Brazil stands out as a viable region for new cropland requirement to address the global demand for biorenewables production. Nevertheless, despite the large areas of degraded pastureland in Brazil, identifying those for growing the crops avoiding worsening the principal causes of biodiversity loss is an issue to be addressed. We evaluated the ecological feasibility of degraded pasturelands as potential areas for biomass production. We selected four exclusion criteria based on the Brazilian legal framework and the conventions and agreements to which the country is a signatory. In 2021, Brazil had 98.1 Mha of degraded pasturelands with the largest portion (63.9 Mha) experiencing a moderate level of degradation, mostly in Amazon biome (22.3 Mha). In addition, Brazilian legislation for biofuels production (Renovabio) predicts the exclusion of Amazon and Pantanal (a Brazilian wetland) biomes as eligible areas. Those biomes were the first exclusion criteria, remaining 65.1 Mha after its exclusion. In terms of protected areas, another adopted criterion, the land of traditional populations evaluated contains fewer degraded areas (0.3 Mha), when compared to the other Brazilian conservation categories (1.2 Mha). In the excluded degraded pasturelands (55.8 Mha, in total), the restoration of native vegetation should be prioritized to enhance biodiversity loss and the mitigation of climate change. Restoration efforts may vary by region, but agroforestry systems using native species of the biome could be a positive alternative. In addition to prioritizing the recovery of habitat and biodiversity loss, this approach has the potential to decrease local social vulnerabilities and to promote sustainable biorenewables production. By prioritizing the conservation of biological diversity, Brazil still has 42.3 Mha available for biorenewables, which corresponds to almost the total area currently under soybean cultivation in the country. The greater availability of degraded pastureland areas is within the Brazilian savanna. In addition to be a biodiversity hotspot, the Brazilian savanna is also central to water supply, contributing to important river basins in the country. Future work should consider other criteria such as water scarcity and climate vulnerability since it is necessary to evaluate the whole biorenewables’ value chains to assure sustainability.

How to cite: Padgurschi, M., de Souza Henzler, D., Palma Petrielli, G., and A. D. Hernandes, T.: Degraded pasturelands for sustainable biorenewables production: an ecological approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22175, https://doi.org/10.5194/egusphere-egu24-22175, 2024.

EGU24-1188 | ECS | Posters on site | ERE1.3

Stone decay in the underwater environment: examples from Mediterranean archaeological sites 

Luigi Germinario, Isabella Moro, Fabio Crocetta, Patrizia Tomasin, Emanuela Moschin, Franca Cibecchini, Stella Demesticha, Enrico Gallocchio, Judith Gatt, and Claudio Mazzoli

This contribution presents one of the research directions of the project WATERISKULT (https://wateriskult.geoscienze.unipd.it), involving the decay of underwater archaeological sites, in particular of submerged structures and artifacts made of stone. The pilot sites of this project are located in the western, central, and eastern Mediterranean Sea, and include the Roman complex of Baia in Italy, the Hellenistic harbor of Amathus in Cyprus, and the Roman port structures of Anse des Laurons in France. Diving and sampling campaigns were organized therein in the first half of 2023, and were followed by laboratory analyses that explored the state of conservation of different archaeological stone materials (limestones, marbles, tuffs, sandstones, etc.). Microscopic techniques were applied for investigating the stone composition, biofouling, and chemical alteration, observing the surface and stratigraphic features of the sampled materials. Moreover, 3D morphometric techniques allowed for the quantification of the physical damage of the archaeological surfaces. The analytical results were combined with site-specific topographic information collected during the dives and environmental data provided by seawater monitoring agencies. In that way, the interaction between ancient materials and the underwater environment was explored, discussing the relationship between deterioration and a range of different stone and seawater properties.

How to cite: Germinario, L., Moro, I., Crocetta, F., Tomasin, P., Moschin, E., Cibecchini, F., Demesticha, S., Gallocchio, E., Gatt, J., and Mazzoli, C.: Stone decay in the underwater environment: examples from Mediterranean archaeological sites, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1188, https://doi.org/10.5194/egusphere-egu24-1188, 2024.

EGU24-1312 | ECS | Orals | ERE1.3

Thermo-hygric weathering of Carrara Gioia marble monitored with Nonlinear Resonant Ultrasound Spectroscopy 

Marie-Laure Chavazas, Philippe Bromblet, Jérémie Berthonneau, and Cédric Payan

Carrara marble is widely used, in buildings and sculptures, in ancient and recent works. Yet, it can develop deteriorations over time, such as bowing, cracks, expansion, reduction of mechanical strength, when it is exposed to environmental conditions. Previous studies have shown that these deteriorations can result from exposure to temperature variations, and that they can be enhanced by additional humidity variations. However, the mechanisms at stake at the microstructure level are still not well-understood.

This work is therefore focused on the understanding of the degradation mechanisms induced on marble by temperature and humidity fluctuations. Laboratory experiments are carried out on Carrara marble samples first heated at different temperatures and then undergoing thermal, hygric, and thermo-hygric cycles. The temperature investigated during cycling belongs to the mild temperature range (40 – 105 °C) in order to simulate outdoor exposure conditions.

The mechanical state of Carrara marble samples is non-destructively monitored during the cycles with Nonlinear Resonant Ultrasound Spectroscopy (NRUS), through the evolution of resonant frequency and of nonclassical nonlinearity. The first parameter is related to sample stiffness, and the latter is highly sensitive to any change occurring at the microstructure level (micro cracks, friction, capillary effects, etc.). Additionally, microstructural characterization (mercury intrusion porosimetry, optical microscope and SEM observations) is made on marble samples to link the evolution of the NRUS parameters to the changes occurring in marble microstructure.

The impact of heating on marble is first studied for temperatures between 40 and 250 °C, and the progressive granular decohesion of the material is monitored with NRUS. Marble state is also characterized during adsorption-desorption cycles, which shows that relative humidity fluctuations alone do not induce permanent damage. Finally, the influence of thermal cycling at mild temperatures and the impact of combined temperature and relative humidity cycling are studied with NRUS.

How to cite: Chavazas, M.-L., Bromblet, P., Berthonneau, J., and Payan, C.: Thermo-hygric weathering of Carrara Gioia marble monitored with Nonlinear Resonant Ultrasound Spectroscopy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1312, https://doi.org/10.5194/egusphere-egu24-1312, 2024.

EGU24-2818 | Posters on site | ERE1.3

A multidisciplinary approach for the diagnostics of the stone building materials of architectural structures 

Giuseppe Casula, Silvana Fais, Francesco Cuccuru, Maria Giovanna Bianchi, Paola Ligas, and Luciano Cannas

The integrated use of non-destructive geomatic and geophysical techniques such as close-range digital photogrammetry, laser scanner techniques, thermography, sonic and ultrasonic methods, resistivity, etc... for the diagnostics of the stone building materials of architectural structures has become increasingly dependent on the integration of different disciplines of applied research. As is well known many historic monuments are characterized by severe damage due to temporal degradation, problems caused by differential settlements of the foundations and various types of natural hazards. Therefore it is of great interest to test and develop effective, integrated non invasive procedures to detect the conservation state of the building materials of historic structures, and identify and prevent their potential vulnerability in order to preserve their intrinsic characteristics for a long time.

For extensive applications, as well as for investigations on monuments or large architectural elements, scanning and digital high resolution images are particularly useful, thanks to their limited cost, high production and relatively simple reproducibility of the tests. These techniques give useful information on the shallow conditions of the investigated materials. Geophysical techniques such as the ultrasonic and resistivity methods are non-invasive and are considered the most appropriate to evaluate the internal structure and assess the quality of the stone materials of the architectural heritage.

This paper presents an integrated approach that combines advanced geomatic survey procedures, such as close-range photogrammetry (CRP) based on high resolution images and Terrestrial Laser Scanner (TLS) techniques with a few geophysical techniques such as the ultrasonic and resistivity ones in order to test the effectiveness of the integrated approach in providing an effective diagnosis of stone building materials in the Basilica di San Saturnino (Cagliari – Italy). This Basilica is the oldest monument of the town of Cagliari (Italy) and represents an interesting synthesis of different construction techniques with heterogeneous stone materials of different origins. CRP and TLS were applied to the investigated elements with the aim of obtaining a natural colour texturized 2D-3D model with a calibrated scale and coordinates. The geometrical anomaly and reflectivity maps derived from the data of the CRP-TLS survey show the presence of some anomalies worthy of attention, but they were referred to the shallow materials. A further investigation on site using the ultrasonic pulse velocity (UPV) and electrical resistivity techniques were performed to investigate the materials in depth. The results of the CRP and TLS techniques allowed the best design of the ultrasonic and electrical techniques and also proved to be useful in the data interpretation phase.

Acknowledgements: The authors would like to thank the Ministero della Cultura - DIREZIONE GENERALE MUSEI - DIREZIONE REGIONALE MUSEI SARDEGNA (ITALY) for their kind permission to work on the San Saturnino Basilica.

How to cite: Casula, G., Fais, S., Cuccuru, F., Bianchi, M. G., Ligas, P., and Cannas, L.: A multidisciplinary approach for the diagnostics of the stone building materials of architectural structures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2818, https://doi.org/10.5194/egusphere-egu24-2818, 2024.

EGU24-4340 | ECS | Posters on site | ERE1.3

Black Crusts as Geochemical Archives: Preliminary Results from Antwerp, Belgium 

Sofia Deboli, Silke Visschers, Blanca Astray Uceda, Adela Šípková, Katrin Wilhelm, and Tim De Kock

Interaction between the historical built environment and environmental pollution can result in the accumulation of weathering crust on building material surfaces. A subgroup of weathering crusts are black crusts, which consist of gypsum layers formed by sulfation on calcium-rich substrates. These crusts occur more often and are more pronounced in polluted environments such as urban settings. As a result, they can incorporate particulate matter, polyaromatic hydrocarbons, and heavy metals. Black crusts can act as non-selective passive samplers, accumulating distinct layers of air contaminants depending on historical pollution levels.
Existing studies provide only coarse-resolution reconstruction of pollution, differentiating solely between inner and outer crust layers. Just a few explore the correlation between different periods of exposure to pollution and the variation of the composition of these crusts. This study focuses on the stratigraphic analysis of black crusts to assess their potential as a reliable geochemical archive for the reconstruction of past anthropogenic pollution within urban settings.
Following technological developments in transportation and combustion, the composition of pollutants in the atmosphere has evolved over the centuries, likely reflected within weathering crusts where pollutants accumulate. For the identification of past air pollution signatures, lead can serve as a useful tracer due to its isotopes, their presence is the result of different historical pollution sources. Variations in the ratios of lead isotopes provide a means to attribute and differentiate among these pollution sources. For lead isotope analysis, high-resolution laser ablation mass spectrometry will be used to distinguish between 206Pb, 207Pb, and 208Pb.
This study deepens the understanding of localized pollution levels in urban settings, allowing the implementation of conservation interventions including cleaning and consolidation, strategies to mitigate the impact on human health, local ecosystems, and biodiversity, and to support urban planning.

How to cite: Deboli, S., Visschers, S., Astray Uceda, B., Šípková, A., Wilhelm, K., and De Kock, T.: Black Crusts as Geochemical Archives: Preliminary Results from Antwerp, Belgium, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4340, https://doi.org/10.5194/egusphere-egu24-4340, 2024.

EGU24-7547 | ECS | Posters on site | ERE1.3

Biodeterioration of historical buildings and sites in north of Lake Tana, Ethiopia: a preliminary investigation 

Ayenew Demssie, Tim De Kock, Natalia Ortega-Saez, and Blen Gemeda

Lake Tana is the largest lake in Ethiopia and the source of the Blue Nile. The lake is protected as a natural heritage site. It is surrounded by wetlands that provide a sanctuary to a diverse set of flora and fauna some of which are endemic to the region. It is also a culturally significant area. Surrounding the lake and on the islands are found tens of stone built monasteries, churches, bridges and palaces built in the Gondarine period (17th and 18th Century AD) and earlier. However, these buildings are subjected to biological growth in many different types that cause  discoloration and  degradation. The short and intense rainy season contributes to the nature, diversity and intensity of biological colonization of these stone structures. Biofilms, fungi, mosses, lichen and higher plants can be observed, while also small animals such as mites and rodents are agents of bio-deteriorative process. While micro-organisms alter the visual appearance, roots of higher plants are responsible for more severe physical decay on the site and building level, increasing also the impact of moisture-related weathering in decayed locations. However, micro-organisms can also alter the surface properties of materials, like water absorption and retention, and it is currently not well understood to what extend these contribute to the observed forms of degradation, like chipping, fissuring, cracking, etc. 

This poster aims to address some of the key challenges of managing cultural heritage sites found in a complex, evolving and vulnerable ecosystem, i.e. Lake Tana. Factors such as intense rainfall, humidity, the state of the structures, intensification of agriculture and the perspectives of local communities and stakeholders will be evaluated.

How to cite: Demssie, A., De Kock, T., Ortega-Saez, N., and Gemeda, B.: Biodeterioration of historical buildings and sites in north of Lake Tana, Ethiopia: a preliminary investigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7547, https://doi.org/10.5194/egusphere-egu24-7547, 2024.

EGU24-10672 | Orals | ERE1.3

Creating a holistic view on the situation of historic parks and gardens 

Jürgen Moßgraber, Tobias Hellmund, Jürgen Reuter, Lola Kotova, and Katharina Matheja

Extreme weather events due to climate change not only affect nature, but can also impact historical buildings, collections, and historic parks and gardens. Assessing the extent to which cultural heritage is threatened by such weather and climate events is an interdisciplinary task that requires the collaboration of experts from heritage preservation and restoration, climate research, natural and engineering sciences, social and economic sciences, landscape architecture, informatics, and more.

Due to this complexity and the abundance of available information, modern IT tools are crucial in explaining the condition of cultural heritage sites to decision-makers and providing insights into future developments. To get a better understanding of the situation of historic parks and gardens, a knowledge platform can offer map-based visualization of data. The biggest challenge in developing such a platform was the integration and processing of relevant data. Due to the interdisciplinary nature of the field and the heterogeneity of the data, it was designed to be able to flexibly integrate and process various types of data. For example, the platform incorporates:

- (Live) sensor data,

- Severe weather risk maps,

- Climate projections and models,

- Expert knowledge incl. tree cadasters,

- Image and video materials, and

- Unstructured documents

This integration aims to provide users with a comprehensive view of their properties.

As part of the project, soil moisture sensors were deployed in Sanssouci Park in Potsdam Germany to monitor soil moisture levels over an extended period of time. These sensors allow for the measurement of soil moisture and temperature at a depth of one meter. A total of 10 sensors were placed at representative locations to provide insights into the irrigation needs of the property. The sensors transmit their data using LoRaWAN (Long Range Wide Area Network), a wireless communication technology that can reliably transmit smaller amounts of data over long distances with low energy consumption. Given the vastness of the Sanssouci Park case study, this approach is suitable as it allows the sensors to be placed in relevant locations without having to consider technical constraints.

The collected data is stored using a FROST server, which is an open-source software project that enables the capture of time series data, including their metadata. The FROST server implements the SensorThings API, a standard of the Open Geospatial Consortium, which aims to standardize the description of sensor data and simplify their reuse. For the visualization of the captured sensor data, a map view has been developed that allows for the positioning of the sensors and the display of their measured data.

How to cite: Moßgraber, J., Hellmund, T., Reuter, J., Kotova, L., and Matheja, K.: Creating a holistic view on the situation of historic parks and gardens, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10672, https://doi.org/10.5194/egusphere-egu24-10672, 2024.

EGU24-11004 | Orals | ERE1.3

ERODEM: Exploring Carbonate Rock Recession through Data Fusion of Extensive Experimental Data via Machine Learning 

Claudio Mazzoli, Chiara Coletti, Luigi Germinario, Lara Maritan, Riccardo Pozzobon, Nereo Preto, and Dimitrios Kraniotis

Pollution and climate change raise increasing concerns about the vulnerability of cultural heritage. In carbonate rocks, the primary concern is surface recession, which severely impacts the readability of details, preventing us from transmitting our legacy to future generations. Recession equations available in the literature are highly inadequate due to the complex relationship between climate conditions, hygrothermal (HT) behaviour, and stone textures. This is related to the limited set of parameters used by different authors and to the basic statistical approach used in their fitting processes.

Through this research, we aim to develop a robust and reliable model to predict stone recession, employing Machine Learning algorithms supported by Multivariate Statistical Analysis. We will examine a large database of surface recession measurements obtained from different types of carbonate rocks, which differ in their textural features (e.g. grain size, porosity) and HT behaviour (e.g. water vapour permeability), and of the relative micro-climate conditions under which they have been exposed during outdoor experiments. Additional recession data will be derived from laboratory experiments using an autoclave, allowing precise regulation of pH and temperature of water in contact with stone samples. Validation of the predictive model will involve comparing the recession predictions based on the time series of climate data and material characteristics with the observed recession obtained through the meticulous comparison of historical plaster replicas with the original monuments. This comprehensive analysis aims to ensure the model accuracy in capturing the real-world complexities of carbonate rock surface recession under varying environmental conditions.

 

Acknowledgement:

ERODEM project was funded by the Department of Geosciences through the “Progetto Premiale” call. This initiative is part of the larger project "Le Geoscienze per lo Sviluppo Sostenibile," funded by the Italian Ministry of University and Research (MUR) within the frame of the “Progetti di Eccellenza 2023-2027”.

How to cite: Mazzoli, C., Coletti, C., Germinario, L., Maritan, L., Pozzobon, R., Preto, N., and Kraniotis, D.: ERODEM: Exploring Carbonate Rock Recession through Data Fusion of Extensive Experimental Data via Machine Learning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11004, https://doi.org/10.5194/egusphere-egu24-11004, 2024.

EGU24-12505 | Posters on site | ERE1.3

Sustainability and cultural heritage conservation: re-use of sand from deconstruction renders 

Beatriz Menéndez, Victor Yameogo, and Elhem Ghorbel

The European project SCORE (Sustainable COnservation and REstoration of built cultural heritage, GA 101007531) deals with a two-way assessment of impacts of the environment on materials and of materials on the environment. Indeed, climate conditions and atmosphere composition determine built cultural heritage (BCH) materials’ behaviour and, at the same time, BCH conservation processes (products and techniques) impact greenhouse gases emissions and then climate change.

The objective of this work is to study the feasibility of recycling old mortars and plasters from an existing building to extract the sand with the aim of reusing it to produce new mortars for the renovation of the built heritage. Old mortars and plasters were mainly made with "natural" sands, generally alluvium and river sands, available near the site. These sources of sand may no longer be available or have become scarce. The use of different sands from the original ones in restoration plasters has consequences on the aesthetic properties of the new plasters applied during the renovation, which often requires the use of additives and dyes. To solve this problem, one possibility is to extract the original sand from deconstruction mortars, taken for example from renovation sites.

We tested the proposed method on a site in Paris. Deconstruction mortars were crushed and the sand was recovered, characterized and used for the formulation of new mortars by adding lime and water. Washing methods with water and acid washing solutions have been tested in order to obtain sands free of debris and lime agglomerates. Citric acid was used because it presents good lime dissolution results and is quite easy to employ in restoration works. Microscopic observations were made to determine the effectiveness of each washing solution. Sands washed only with water show some remains of lime on the grain surfaces whereas washing the grains with citric acid solution (2 %) produces excellent results.

In addition, mortars formulations with different grain size of recycled sands were made. These formulations consist of a mixture of recycled sand, water and an additive lime in equal proportions. Specimens of 4 x 4 x 16 cm were produced and their mechanical properties were measured at 28 days of age. During the maturation time, the samples are kept in an environment with constant humidity and temperature, to optimize the conditions of hydration, carbonation and maturation.

The results obtained show that the mechanical properties of mortars made from recycled sand are acceptable and that these are intrinsically linked to the grain size and quality of the sands. The mechanical properties of mortars formulated with recycled sands of the right grain size are similar to those formulated with commercial natural sand. A large part of the recycled sand, after just washing with water, can be used in the formulation of new mortars with regard to standards and aesthetic properties.

How to cite: Menéndez, B., Yameogo, V., and Ghorbel, E.: Sustainability and cultural heritage conservation: re-use of sand from deconstruction renders, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12505, https://doi.org/10.5194/egusphere-egu24-12505, 2024.

EGU24-13376 | Posters on site | ERE1.3

Durability of Built Cultural Heritage Materials under different climate conditions 

Luis Valdeon, Beatriz Menendez, Javier Reyes, and Inge Rörig-Dalgaard

The European project SCORE (Sustainable COnservation and REstoration of built cultural heritage, GA 101007531) deals with a two-way assessment of impacts of the environment on building materials and of materials on the environment. Indeed climate conditions and atmosphere composition determine built cultural heritage (BCH) materials’ behaviour and, at the same time, BCH conservation processes (products and techniques) impact greenhouse gases emissions and eventually climate change.

This contribution presents a characterization of the effects of different climate conditions on several traditional restoration mortars, bricks and calcareous stones. A common strategy plan was designed in order to compare the results of weathering exposition experiments in several location: North of Spain, North-West of France, Denmark and Calakmul Biosphere Reserve in Mexico. Some of the presented results correspond to real conditions experiments started before the common exposition campaign but they will be presented because of their interest.

The exposition support is a frame with a plate surface of 1mx1m, placed at 1m height under two exposure conditions: inclination of 10° and at horizontal position. The exposition frame is oriented facing the predominant wind direction. For comparison we chose to expose two kinds of hydraulic lime mortars from Saint Astier company, bricks from Denmark and Mayan calcareous stone from Campeche area treated with Ca(Zn (OH)3)2·2H2O nanoparticles (CZ) in order to improve their behaviour under the exposure conditions.  Mortar coupons had dimensions of 20 x 10 x  3 cm, while the stone samples ones were 5 x 5 x 3.5 cm. A first set of mortars consisting of two-layer sample was tested with a base of a salt protection mortar and a 1 cm upper layer with a finishing mortar. A second set of mortars consists of a monolayer of a masonry restoration mortar. In each specific site, local or recipe mortars have been also exposed. 

Samples have been characterized before exposition and at regular time intervals during the exposition period, that is not finished. Weight, hardness, deterioration patterns, colour and P wave velocity have been measured at different sample locations. Results indicate that in French locations commercial mortars become better than home-made ones, probably due to the absence of any additive in the home-made recipes. First results for the Spanish exposition site show that velocity measurements start detecting some points where layers begin to separate from each other. Some microcracks start to develop at the surface of one type of mortar respecting the monolayer one.  Finally colour changes have been detected in the two layers masonry mortar.

Such gradual (also visible) degradation has previously also been documented in laboratory examination of fired clay bricks submerged in liquids with varying pH (3,5,7,9,11) and varying duration up to more than one year (432 days). Increasing submersion duration resulted in increased degradation, whereas the different pH values representing exposure to various conditions (acid rain, traditional rain, connection with alkaline mortar) revealed different degradation patterns.

The stone coupons improve some of their properties due to CZ addition at initial periods, but they tend to decrease over time.

How to cite: Valdeon, L., Menendez, B., Reyes, J., and Rörig-Dalgaard, I.: Durability of Built Cultural Heritage Materials under different climate conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13376, https://doi.org/10.5194/egusphere-egu24-13376, 2024.

EGU24-13920 | ECS | Orals | ERE1.3

Vulnerability Index of Critical Infrastructure in Greater Kuala Lumpur Fault Zone, Malaysia 

Rabieahtul Abu Bakar, Nurin Faiqah Noorazri, Zakaria Mohamad, Anggun Mayang Sari, and Zamri Ramli

The Greater Kuala Lumpur (Greater KL) region, a pivotal hub of Malaysia's economic growth, confronts a burgeoning challenge amid rapid urbanization. Unprecedentedly, it is vulnerable to seismic reactivation possibilities from the dormant Kuala Lumpur Fault Zone (KLFZ). With a comprehensive integration of geospatial technologies, to dissect the geological intricacies of the KLFZ and assess the vulnerability of critical infrastructure within Greater KL. The research aims to bridge the realms of geology and infrastructure engineering, providing actionable insights for policy decisions and urban planning to enhance the region's resilience to seismic events. The problem statement underscores the urgent need for a comprehensive investigation into the interplay between the geological characteristics of the KLFZ and the vulnerabilities in infrastructure. Despite the economic significance of Greater KL, a notable research gap hinders effective mitigation and preparedness strategies. The aim is to unravel the distinctive features of the KLFZ, assess infrastructure vulnerability, and inform policies for safeguarding against potential seismic threats. The methodology unfolds systematically, employing geospatial analysis, remote sensing, and geological data. The research adopts a meticulous data acquisition approach, integrating Sentinel-2 imagery and a seismotectonic map of Malaysia to delineate the fault zone. The extraction of critical infrastructure is conducted with precision, considering the guidelines from the U.S. Cybersecurity and Infrastructure Security Agency. The subsequent steps involve buffer zone creation, overlay analysis, and data classification to develop a vulnerability index. The expected outcome revolves around a comprehensive understanding of the KLFZ and its implications on infrastructure vulnerability. The methodology employs detailed mapping and geospatial analysis, providing insights into fault characteristics, seismic hazards, and critical infrastructure susceptibility. The research aims to contribute a robust foundation for disaster preparedness, urban planning, and engineering strategies, fostering the safety and stability of Greater KL against seismic risks. This research contributes to the broader discourse on urban resilience and disaster management, emphasizing the significance of geomatics in addressing the complex challenges posed by active fault zones or the possibilities of reactivated fault zones. The findings hold practical implications for policymakers, urban planners, and geospatial professionals, offering a nuanced perspective on the intricate relationship between geological factors and infrastructure vulnerabilities in dynamic urban landscapes. In conclusion, this research endeavours to unravel an inform evidence-based decision-making, contributing to the sustainable development and safety of the Greater KL region.

How to cite: Abu Bakar, R., Noorazri, N. F., Mohamad, Z., Sari, A. M., and Ramli, Z.: Vulnerability Index of Critical Infrastructure in Greater Kuala Lumpur Fault Zone, Malaysia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13920, https://doi.org/10.5194/egusphere-egu24-13920, 2024.

EGU24-15733 | Orals | ERE1.3

Condition assessment of limestone tombs Theban Necropolis (Luxor, Egypt) 

Ákos Török and Tamás Zomborácz

The Theban Mountain, on the west bank of the river Nile, near Luxor is internationally known as the burial site of Egyptian Dynasties. The current study focuses on four tombs dating back to the late Old Kingdom and the First Intermediate Period. The tombs are located on the hill's southern slope and were cut into the rock. Their geometry is characteristic since at least six horizontal rows were excavated above one another. Sedimentary rocks of the study area form parts of Tarawan Cretaceous, Esna Shale and Theba Limestone formations. All four tombs were once lavishly decorated with wall paintings and reliefs carved directly into the carbonatic rocks. Until now, these structures have gone through considerable erosion in addition to the occurring damages resulting from their reuse as modern habitations until the late 20th century. Thus, most of the tombs’ decorations have perished or heavily deteriorated. Since 1983 a Hungarian Archaeological Mission has been exploring the site. Numerous attempts have been made to reconstruct the fragmented walls and conserve the remaining works of art, however, very little effort has been made to understand the deterioration process and its origins. This research describes the geological conditions, petrology and sedimentology of local carbonates, fracture pattern, micro-climatic conditions of the tombs, and decay forms. Stratification, micro-cracking and discontinuities were also mapped. The painted and carved surfaces were documented, and the condition of the walls was assessed. On-site tests included moisture content measurements (vertical profiling) and the detection of surface strength by non-destructive methods. Sensors were placed at various parts of the tombs, recording temperature and relative humidity. The main trigger mechanisms of deterioration processes were identified and preservation measures were made. This study aims to provide an example that helps assess the conditions of rock-cut tombs in arid climates and the changes linked to micro-climatic conditions.

How to cite: Török, Á. and Zomborácz, T.: Condition assessment of limestone tombs Theban Necropolis (Luxor, Egypt), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15733, https://doi.org/10.5194/egusphere-egu24-15733, 2024.

EGU24-15931 | Posters on site | ERE1.3

Mapping Vertical Greenery on Historic Buildings in Neighbourhoods with High Environmental Risks: A Case Study in Antwerp, Belgium 

Eda Kale, Marie De Groeve, Lena Pinnel, Yonca Erkan, Piraye Hacıgüzeller, Scott Allan Orr, and Tim De Kock

Ongoing urbanization has increased the impact of the urban heat island effect, air pollution, and noise pollution while limiting the space for green areas. Therefore an urgent action is required to mitigate these environmental risks. Vertical Greenery (VG) has emerged as a sustainable and viable solution across diverse contexts, but it is generally not always accepted for historic buildings by experts. The scepticism is rooted in concerns about the potential adverse effects on conservation practices and heritage values. Contrary to expert concerns, VG on historic buildings is seen as a response to reducing the urban heat island effect in high environmental risk areas by the users.

We conducted a comprehensive study in Antwerp (Belgium), a city actively advocating for VG solutions. We selected three neighbourhoods, namely Historical Centre, Oud Berchem, and Borgerhout Intra Muros Zuid, where air pollution, noise, and heat stress are above the risk level. We documented the VG implementations in these three neighbourhoods through the use of GIS and field survey methods. The prevalence of VG in case sites was analysed based on factors such as the heritage status of buildings and the morphology of streets, which could pose challenges to the implementation of VG.

The results suggest that VG is present in up to 14% of all buildings in the selected neighbourhoods. While in the Historical Centre, 59% of the buildings with VG have a heritage designation. As such, narrow streets and heritage designation do not prevent VG implementation in densely built neighbourhoods with green space deficits.

While this study provides site-specific results, the analysis methods we used can guide policymakers and urban planners to explore VG's adaptability to historic buildings in the development of effective integration strategies.

How to cite: Kale, E., De Groeve, M., Pinnel, L., Erkan, Y., Hacıgüzeller, P., Orr, S. A., and De Kock, T.: Mapping Vertical Greenery on Historic Buildings in Neighbourhoods with High Environmental Risks: A Case Study in Antwerp, Belgium, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15931, https://doi.org/10.5194/egusphere-egu24-15931, 2024.

EGU24-16698 | ECS | Posters on site | ERE1.3

The influence of orientation and leaf area indices of a vertical green wall on historic building materials 

Marie De Groeve, Eda Kale, Scott Allan Orr, and Tim De Kock

Built heritage is a vital component of urban environments and is rich in cultural and economic values. These buildings are abundant in city centres and have been the site of development for several centuries. They have created dense urban environments, exhibiting strong urban heat island effects. Ground-based vertical greening is a widely used green initiative in dense urban environments to mitigate the current climate stressors due to its small footprint and its ability to cover a large surface area with vegetation. The impact of this green initiative on the materials and structural integrity of built heritage is currently poorly understood and thus the focus of this research.


Several studies have already proven the efficacy of ground-based vertical greening in fostering a more stabilized condition on the underlying wall surface, characterized by reducing the amplitude of temperature and relative humidity fluctuations and the amount of solar irradiation. More stable conditions can imply a lower risk of common degradation processes, such as freeze-thaw weathering and salt crystallization, in historic building materials. 


Since the extent of the vertical greening performance and the deterioration of building façades strongly depend on the orientation of the façade, part of this research aims to establish a relationship between those two variables while considering the orientation of a building façade. Monitoring case studies in the historic city centre of Antwerp during summer develops an understanding of the shading performances of vertical greening and characterises the boundary conditions, such as orientation or leaf area index (LAI), that signify the extent of efficacy. The current case studies reveal a positive correlation between the LAI and the shading potential of vertical greening and highlight the significant role of orientation in mitigating the environmental parameters on the wall surface, as the cooling processes of vegetation mainly depend on the amount of solar irradiation. More specifically, the highest leaf area index and a south or west orientation show us the most significant cooling behaviour during the day which can reduce the risk of salt crystallization the most. The shading performance of vertical greening is only one of the several mechanisms determining the impact of vertical greening on the local environment and the subjected historic materials. 

How to cite: De Groeve, M., Kale, E., Orr, S. A., and De Kock, T.: The influence of orientation and leaf area indices of a vertical green wall on historic building materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16698, https://doi.org/10.5194/egusphere-egu24-16698, 2024.

EGU24-18747 | Posters on site | ERE1.3

Insight to the effect of adding cow hair and pig bristles to lime mortars: Towards obtaining more sustainable construction products recycling waste animal byproducts. 

Eduardo Molina-Piernas, María Jesús Pacheco-Orellana, Salvador Domínguez-Bella, Javier Martínez-López, and Ángel Sánchez-Bellón

The increase in demand for natural resources due to the growth of the world population is generating an unprecedented increase in waste, and the unsustainability of this situation has induced the change towards a more environmentally friendly economy, the so-called “Green Economy”. Through the new policies for waste management, its reuse in other industrial processes is being encouraged, favouring “Zero Waste” initiatives. This aims to minimize the emission of greenhouse gases that could accelerate climate change, as well as to the reduction of associated energy expenditure. In Spain, two of the sectors that generate the most waste are construction and agriculture, especially linked to animal by-products not intended for human consumption (SANDACH, by its Spanish acronym). In line with these new trends, new initiatives are required to promote the reuse of this waste and the development of more sustainable construction products that involve the reduction of the carbon footprint. Therefore, the main goal of this work is to better understand the effect of adding natural fibres of animal origin, in this case cow hair and pig bristles, to lime mortars for their use both in modern construction and its application in repair historical mortars. In this way, we aim to achieve a double goal: on the one hand, to obtain information about the quality of the result of combining these products; and on the other hand, to reduce CO2 production by avoiding the incineration of animal by-products not usable in other sectors, finally producing a more sustainable mortar. The specific objectives proposed are: 1) to compare the quality of lime mortars considering the addition of hairs, bristles or with combined proportions of both fibres, with respect to control samples without fibres; 2) to evaluate if the speed and degree of carbonation are affected by the addition of fibres; 3) to identify deterioration processes that may reduce the quality of lime mortars due to aging in the laboratory and outdoors; and 4) to establish optimal production and handling conditions in collaboration with regional or national companies interested in the use of this product. To achieve these goals, in this first stage we will present the preliminary results comparing a mortar without fibres as control sample, with 3 sets of samples with different fibre proportions (containing 10 g or 20 g of cow hair or pig hair per 2 kg), as well as a mixture of both types of fibres (5+5 g and 10+10 g per 2 kg). Based on these results, it will be possible to consider the possibility of increasing the quantity of fibres until reaching an acceptable limit of workability and usefulness without compromising the quality of these mortars.

Acknowledgements: This study was financially supported by the Research Project TED2021-132417A-I00 funded by MCIN/AEI /10.13039/501100011033 and by the European Union NextGenerationEU/ PRTR and E. Molina-Piernas acknowledges co‑funding from the European Social Fund (D1113102E3) and Junta de Andalucía.

How to cite: Molina-Piernas, E., Pacheco-Orellana, M. J., Domínguez-Bella, S., Martínez-López, J., and Sánchez-Bellón, Á.: Insight to the effect of adding cow hair and pig bristles to lime mortars: Towards obtaining more sustainable construction products recycling waste animal byproducts., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18747, https://doi.org/10.5194/egusphere-egu24-18747, 2024.

Cultural heritage in Sweden is increasingly at risk from a number of climate change related factors. These include the direct effects of erosion, flooding, landslides, melting permafrost and related threats, but also increasing industrial activity in the Arctic associated with energy production and the extraction of minerals for 'green' technologies. Whilst much of the physical science of climate related threats is well understood, the practical implications at the local and regional level, as well as the hands-on management of these risks has been somewhat neglected. In a recent pilot study we exposed problems in government planning processes, and in particular that even though the general risks and potential consequences are known, Sweden lacks any form of coordinated system for the prioritisation of sites in terms of conservation, protection, documentation or abandonment. On an international level, we also identified a tendency to focus on above ground archaeological remains and high status sites and monuments. Cultural landscapes, preserved organic and palaeoecological archives, and as yet undiscovered sites are, on the other hand, are less frequently studied and often neglected in planning processes.

Many important cultural heritage sites and landscapes are in close proximity to, and potentially impacted by, transport infrastructure. As the climate warms, roads in particular are increasing in number and traffic volume in the northern areas of Scandinavia. In cooperation with the Swedish Transport Administration we developed a prototype GIS system for assisting in the evaluation of climate related threats to sites in close proximity to transport infrastructure. Three areas were investigated in more detail, ranging from temperate coastal to sub-Arctic rural settings and including a broad variety of cultural heritage types from prehistoric to historical. Case studies looked at particular secondary risks, including the expanding use road salt, and the use of specific datasets (e.g. historical maps, erosion models). This work exposed not only the potential for using such a system in research and planning, but also a number of issues in the uncritical use of publicly available national databases for transport infrastructure, climate threats, and cultural heritage. For example, the poor spatial resolution of risk maps in the Arctic and the poor locational accuracy of many older archaeological and historical investigations can lead to an incorrect assessment of threats. Similarly, much of the rural north of Sweden is poorly surveyed, and existing predictive models for locating unknown sites are inadequate. There is thus a potential bias between risk assessment in the south and the north, and between urban and rural areas. A clear potential exists for the further development of GIS based models with a greater capacity for visualizing and, to an extent compensating for, variability in the quality of the underlying data.

This presentation will show some results and conclusions from these studies, as well as some preliminary findings from ongoing research into the reasons behind problems of implementing strategies for the prioritisation of cultural heritage threatened by future climate change.

How to cite: Buckland, P. and Antonson, H.: Challenges and potential for predicting and managing climate threats to cultural heritage in Sweden, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18769, https://doi.org/10.5194/egusphere-egu24-18769, 2024.

Treatments intending to prevent stone damage sometimes accelerate deterioration unexpectedly. It would be meaningless if the use of protective agents in a more severe deterioration than originally intended. A combination of the properties between agents and stones determines the ability of protective agents to penetrate the stone. In particular, it is expected to depend on the pore diameter distribution of the stone. The present study focuses on freeze-thaw and salt weathering tests were carried out by using several types of tuffs to verify this. The stone materials used were Oya tuff, Nikka tuff, Tatsuyama tuff, Ashino tuff, and Towada tuff, which have different pore size distributions, different strengths, and different durability to salt weathering. In rocks with a high proportion of micro-pores and low resistance to salt weathering, the use of protective agents (water repellents) can delay the onset of surface deterioration. On the other hand, rocks with a high proportion of large pores (>100.5 µm) and not less resistant to salt weathering were found to be more likely to deteriorate more severely with an earlier onset of surface deterioration than untreated stones. It is considered to be because the salts crystallize at greater depths when protective agents are applied, whereas they crystallize only at the surface in the case of untreated rocks, and the crystalline pressure causes fracture from the deeper layers. Therefore, when using protective agents, it is necessary to understand the combination of rock properties such as rock structure, pore size, and strength of the rock sample with crystal pressure.

How to cite: Oguchi, C. and Ikeda, Y.: Effect of pore size distribution on the application of water repellent for preventing deterioration of stone materials., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19171, https://doi.org/10.5194/egusphere-egu24-19171, 2024.

Identifying and determining buried archaeological structure limits are crucial for archaeological prospection surveys. The archaeological prospection surveys can shed light on protecting cultural heritage. Magnetic is one of the most applied methods in archaeological surveys to plan the excavation process. It aims to identify buried temples, graves, city walls, and other structures by interpreting the data obtained from magnetic measurements, which is one of the non-destructive geophysical exploration methods. In the process of interpretation of magnetic data, many methods have been developed, such as Horizontal Gradient Magnitude, Analytical Signal, Theta Map, and Tilt Angle methods, which can generate information about the boundaries of potential subsurface features. By analyzing the gradients of the magnetic field data, inferences can be made to determine the edges of subsurface potential archeological structure distributions.

The Olympos is an important ancient city in Antalya (the south of Turkey) and contains many structures from the Byzantine period. This research aims to detect the pipe drain as a water system of the Episkopeion region in the Olympos ancient city. To this end, Tilt Angle (TA) and Edge detection field (ED) methods were tested on the magnetic map of the synthetic model. The horizontal boundaries of the potential pipe drain elements of the region were analyzed by applying the same procedures on the magnetic map obtained from the magnetic measurements on the area that has not been excavated in the Episkopeion archaeological excavation area. Magnetic measurements were carried out in 4 different regions within the Episkopeion area, and each area was numbered and analyzed separately. Combining the results obtained, an integrated visualization of the water system in the area was achieved.

Keywords: Archaeological Prospection, Edge Detection, Olympos, Tilt, Angle, Pipe drains.

 

How to cite: Deniz Toktay, H.: Edge detection of magnetic data: Preliminary results of application to Episkopeion region in Olympos Ancient City (Antalya), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19203, https://doi.org/10.5194/egusphere-egu24-19203, 2024.

EGU24-605 | ECS | Posters virtual | ERE1.5

Disentangling social perspectives on the use of reclaimed water in agriculture using Q methodology 

Cintya Villacorta Ranera, Irene Blanco Gutiérrez, and Paula Novo Nunez

Water scarcity due to climate change and increased water demands is driving the use of non-conventional water sources, including reclaimed water, particularly in agriculture. In many EU countries affected by droughts, reclaimed water has become an important component of the overall water mix. For example, in Spain, Europe’s most arid country, reclaimed water is 560 hm3/year (nearly 10% of the treated wastewater).

The use of reclaimed water has many advantages, but it also faces significant barriers. The lack of social acceptance has been described as one of the major obstacles. However, understanding how different stakeholders perceive the use of reclaimed water has not been addressed in depth the literature so far. Existing studies are scarce and fragmented. They focus on a single type of stakeholder (farmers or consumers), ignoring the perceptions and eventual acceptance of different stakeholder groups directly or indirectly impacted by reclaimed water.

This study attempts to fill this gap by exploring the plurality of perspectives on the use of reclaimed water for irrigation in Spain. To do so, we applied Q-methodology and conducted twenty-three interviews with key stakeholders, including representatives of public administration, environmental groups, farmer associations, food retailers, consumer organizations, water treatment companies and water reuse experts. As part of the Q study, stakeholders were asked to sort according to their level of relative agreement 36 statements related to different socio-economic, technical, environmental, institutional and political aspects of reclaimed water. The results were analysed using principal component analysis in R ('qmethod' package).

Our study found three discourses: 1- Reclaimed water is a guarantee for water supply in agriculture, 2- Reclaimed water has the potential to be a sustainable water resource and 3- Reclaimed water has a negative impact on the environment. These discourses show different ways of understanding reclaimed water. Although stakeholders had diverse perceptions, there is a certain agreement that the public administration has the will to promote the use of reclaimed water and therefore it is key to promote reclamation projects in agriculture.

They also agree that most consumers are not informed about the quality of reclaimed water and its benefits in the agricultural sector, which leads to a certain social reluctance to use it, and to avoid this, awareness campaigns would be necessary to increase the social acceptance of reclaimed water.

Therefore, some discourses conclude that it is possible that reclaimed water may have pollution problems, but it is also true that the potential for improvement in reclamation technology can avoid them. Regarding the reduction of ecological flows, it is important to study this on a case-by-case basis, as this problem tends to occur in inland areas, although not always.

Finally, the question of who should pay for water regeneration is very controversial and the best solution is to share the costs between the different stakeholders, with the purification and reclamation being carried out tipping fee, and the farmers, with the help of the administration, bearing the costs of the infrastructure and controls from WWTP.

How to cite: Villacorta Ranera, C., Blanco Gutiérrez, I., and Novo Nunez, P.: Disentangling social perspectives on the use of reclaimed water in agriculture using Q methodology, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-605, https://doi.org/10.5194/egusphere-egu24-605, 2024.

EGU24-1342 | ECS | Orals | ERE1.5 | Highlight

Increasing water footprints of flex crops 

Oleksandr Mialyk, Markus Berger, and Martijn J. Booij

Flex crops—crops with multiple end-uses that can be flexibly interchanged—play an important role in our society. Due to high nutritional and energy contents, they became widely used in various industries, providing food, animal feed, biofuels, and other chemical components. However, a limited number of studies exists on the environmental pressures of such crops, specifically concerning water resources.

Here, we aim to quantify the water footprints of main flex crops—namely maize, oil palm, soya beans, sugar cane, coconut, cassava, rape seed, and sunflower—using a recently published database on gridded water footprints of the world’s major crops in the 1990–2019 period. Our study reveals three key developments:

  • All flex crops experienced large water-productivity gains in response to increasing crop yields (less water is needed per tonne).
  • The global water footprint of flex crops has increased by more than one trillion cubic metres as productivity gains were insufficient to meet rapidly growing demand.
  • The production of flex crops has been concentrating around main exporting regions, most notably in Latin America and South-eastern Asia.

As demand keeps increasing, this raises a need for further research addressing the sustainability of flex crops. In particular, regarding the potential links to green and blue water scarcity, exposure of global supply chains to socio-economic and climatic risks, and the role of flex crops in our society.

How to cite: Mialyk, O., Berger, M., and J. Booij, M.: Increasing water footprints of flex crops, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1342, https://doi.org/10.5194/egusphere-egu24-1342, 2024.

EGU24-1481 | ECS | Posters on site | ERE1.5

Overcoming Barriers to Sustainable Rice Production: A Remote Sensing-Enabled Approach 

Nick Kupfer, Carsten Montzka, and Tuan Quoc Vo

In Vietnam, conventional rice cultivation is under strong economic and ecological pressure. Against this backdrop, there is a rising demand for organic products both domestically and globally. In response, OrganoRice aims to facilitate the transition to organic farming in the model provinces of Vinh Long, Dong Thap, and An Giang in the Mekong Delta through a collaborative effort between German and Vietnamese partners. The initiative encompasses not only addressing physical challenges such as soil and water pollution reduction, optimal fertilization, and ecological plant protection but also delves into critical socio-economic dimensions, including enhancing the income of rice farmers and product marketing. The project acknowledges the intricate task of integrating cultural identity and individual farmers into the social fabric of the village community as a crucial factor for success in the conversion process. Direct communication with the rural population is prioritized, and key local stakeholders and scientific institutions, such as Can Tho University, play pivotal roles in ensuring the project's sustainable success.

The Mekong Delta's agricultural landscape is being explored through advanced tools such as remote sensing and hydrological simulations to map, predict, and optimize crop types, agricultural practices (both conventional and organic), and irrigation water pathways. Leveraging European Copernicus satellites Sentinel-1 and Sentinel-2, alongside PlanetScope equipped with radar and multispectral sensors, allows for monitoring plant growth conditions at a high spatial resolution. The analytical process involves examining remotely sensed data through phenological metrics, quantile mapping, and Fourier transform, complemented by conceptual simulations of irrigation flow paths. The initial phase comprises a comprehensive high-resolution time-series analysis of land use and land cover (LULC) dynamics to identify all potential LULCs influencing organic rice farming. Subsequently, irrigation flow path modeling is employed to estimate complex water dependencies. Ultimately, data fusion of LULC and irrigation analysis, combined with crop-specific pesticide data, results in an opportunity map highlighting suitable areas for organic rice farming. This interdisciplinary approach underscores the importance of integrating technological advancements with socio-economic considerations for a comprehensive and sustainable organic farming transition in the Mekong Delta.

How to cite: Kupfer, N., Montzka, C., and Quoc Vo, T.: Overcoming Barriers to Sustainable Rice Production: A Remote Sensing-Enabled Approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1481, https://doi.org/10.5194/egusphere-egu24-1481, 2024.

EGU24-1491 | ECS | Orals | ERE1.5

Modelling Agrivoltaics in a climate perspective for water-energy-food nexus analysis 

Lia Rapella, Philippe Drobinski, and Davide Faranda

Renewable energies (REs) are increasingly important in addressing the challenge of climate change. Their development and widespread use can significantly reduce greenhouse gas emissions from fossil fuels and help mitigate the effects of climate change. To achieve a "net-zero" carbon economy, the transition to a RE system must occur alongside a profound transformation of the agri-food sector. Agrivoltaics (AVs) offers an opportunity to achieve both of these goals simultaneously. AVs provides clean energy and it is an important tool for realizing a sustainable and circular food economy in rural and farming communities. Additionally, by placing photovoltaic (PV) panels over crop fields, AVs can avoid the competition between solar energy and agriculture for land-use. This can also help to mitigate the impact of climate change on crop productivity, which is expected to be negatively affected by a warmer and drier future climate.
In our study, we developed a large-scale sub-grid AVs model to explore the inter-links between climate, the AVs system, and crops. This model enables a comprehensive evaluation of the effectiveness and efficiency of an AVs configuration within the context of the climate-water-energy-food nexus. Our approach involves coupling a PV model with the soil-vegetation-atmosphere-transfer model ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) to construct the AVs module. The PV layer simulates the effects of PV panels, altering solar radiation and wind speed taken from atmospheric forcings. Subsequently, these altered variables, along with other key atmospheric variables like air temperature and precipitation required by ORCHIDEE, are used as inputs to the hydro-vegetation layer. Leveraging ORCHIDEE capability to quantify terrestrial water and energy balances at the land surface, this integration allows for a comprehensive simulation of crop ecosystem behavior within an AVs system. Net Primary Production (NPP), Water Use Efficiency (WUE), and PV power potential (PVpot) are finally computed as ultimate outputs of our model, representing key indicators for the water-energy-food nexus. Focusing on the Iberian Peninsula and the Netherlands, we apply our model to assess three AVs configurations (fix-tilted array, sun tracking, sun antitracking) across three specific years (2015, 2018, 2020) for two types of crops. Specifically, we compare the performance of different configurations among themselves and against the situation without AVs systems to analyze different behaviors depending on climate conditions, crop type, and location and to explore the potential benefits of the AVs systems.

How to cite: Rapella, L., Drobinski, P., and Faranda, D.: Modelling Agrivoltaics in a climate perspective for water-energy-food nexus analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1491, https://doi.org/10.5194/egusphere-egu24-1491, 2024.

The escalating threat of water scarcity presents a dual challenge to both food production and water-related systems. The degradation of conventional water resources (e.g., surface water and ground water), coupled with insufficient investment in infrastructure, has compelled the water sector to seek alternative sources such as Non-Conventional Water Resources (NCW), encompassing reclaimed water reuse and desalination of brackish and seawater, as a long-term strategy, particularly in arid and semi-arid environments where irrigation is a vital component.
Recognizing the substantial potential of NCWs, this research presents the outcomes of an extensive study [1]. The study adopts a multidisciplinary approach, specifically employing Multi-Criteria Decision Making (MCDM), to assess the effectiveness of smart city water management strategies within the framework of NCWs. Utilizing representative criteria, our analysis involves objective judgment, assigns weights through the Analytic Hierarchy Process (AHP), and scores strategies based on their adherence to these criteria.
Our findings underscore the pivotal role of the "Effectiveness and Risk Management" criterion, carrying the highest weight at 15.28%, in shaping strategy evaluation and ensuring robustness. Criteria with medium weight include "Resource Efficiency, Equity, and Social Considerations" (10.44%), "Integration with Existing Systems, Technological Feasibility, and Ease of Implementation" (10.10%), and "Environmental Impact" (9.84%), focusing on ecological mitigation. Recognizing the importance of community engagement, "Community Engagement and Public Acceptance" (9.79%) is highlighted, while "Scalability and Adaptability" (9.35%) address the dynamics of changing conditions. Balancing financial and governance concerns are "Return on Investment" (9.07%) and "Regulatory and Policy Alignment" (8.8%). Two low-weight criteria, "Data Reliability" (8.78%) and "Long-Term Sustainability" (8.55%), emphasize data accuracy and sustainability.
Strategies with higher weights, such as "Smart Metering and Monitoring, Demand Management, Behavior Change," and "Smart Irrigation Systems," prove highly effective in enhancing water management in smart cities. Notably, medium-weighted strategies (e.g., "Educational Campaigns and Public Awareness," "Policy and Regulation," "Rainwater Harvesting," "Offshore Floating Photovoltaic Systems," "Collaboration and Partnerships," "Graywater Recycling and Reuse," and "Distributed Water Infrastructure") and low-weighted strategies (e.g., "Water Desalination") also contribute significantly, allowing for customization based on each smart city's unique context.
This research is of significance as it addresses the complexity of urban water resource management, offering a multi-criteria approach that enhances traditional single-focused methods. It comprehensively evaluates water strategies in smart cities and provides a criteria-weight-based resource allocation framework for sustainable decision-making, thereby boosting smart city resilience. It is essential to acknowledge that results may vary depending on specific smart city needs and constraints. Future studies are encouraged to explore factors such as climate change's impact on water management in smart cities and consider alternative MCDM methods like Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) or Elimination and Choice Expressing the Reality (ELECTRE) for strategy evaluation.

[1] Bouramdane, A.-A., Optimal Water Management Strategies: Paving the Way for Sustainability in Smart Cities. Smart Cities 2023, 6, 2849–2882. https://doi.org/10.3390/smartcities6050128

 

 

How to cite: Bouramdane, A.-A.: Sustainable Management Strategies for Non-Conventional Water Resources: Enhancing Food and Water Security in Arid and Semi-Arid Regions , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2856, https://doi.org/10.5194/egusphere-egu24-2856, 2024.

EGU24-3533 | Posters virtual | ERE1.5 | Highlight

Challenges and opportunities of using reclaimed water for agricultural irrigation in Spain: A hydro-economic analysis.  

Paloma Esteve, Irene Blanco-Gutiérrez, Marina RL Mautner, Samaneh Seifollahi-Aghmiuni, and Marisa Escobar

Growing pressure on water resources and climate uncertainty are driving the need for alternative water sources. In countries with severe water stress, such as Spain, the reuse of water from urban wastewater treatment plants has become a promising opportunity to secure and improve agricultural production. The use of reclaimed water in agriculture offers many significant economic and the environment benefits. In addition to preserving freshwaters, it increases the reliability of water supplies and provides a source of nutrients needed for crop growth and soil fertility. In recent years, the European Union and the Spanish government have promoted the reuse of reclaimed water for irrigation as part of their circular economy strategies. However, the uptake of this practice is still limited and so far deployed below its potential.

This study uses a hydro-economic model to investigate the potential for reclaimed water reuse in agriculture and effective water resource management in the Western La Mancha aquifer in Spain. In this region, groundwater abstraction for irrigation exceeds aquifer recharge, leading to conflicts between rural socio-economic development and water conservation. In this context, reclaimed water reuse is seen as an alternative source to groundwater that can contribute to reduce over-exploitation. An economic optimization model is linked to the hydrology model WEAP (Water Evaluation And Planning system) to analyse management alternatives, that include full compliance with the current water abstraction regime and different levels of reclaimed water reuse from the region’s urban wastewater treatment plants (current level and full potential). Climate uncertainty is also simulated and represented by projected precipitation and temperature changes from a selection of global climate models under different representative concentration pathways (4.5 and 8.5).

The results show that compliance with the abstraction regime can help to mitigate aquifer overexploitation. Reclaimed water reuse represents an additional effort for aquifer recovery, resulting in improved groundwater storage levels. Its effect is particularly relevant under climate change scenarios, although groundwater levels would show a downward trend. However, reusing reclaimed water for irrigation reduces effluent flows to rivers and has a negative impact on meeting the environmental needs of downstream wetlands. At the same time, water reuse could mitigate the negative impact of water scarcity on farm incomes, especially in municipalities with high-capacity treatment plants (> 1Mm3/year) where high value crops (vineyards, olives and horticultural crops) are grown. 

Overall, this research evidence uneven impacts of reclaimed water reuse across the basin. Its contribution to reversing groundwater depletion is limited and should be understood as part of the solution, but not as the solution itself. Our results provide valuable insights into the economic and environmental implications of reclaimed water reuse and can support policy decisions for the adoption of such alternatives for integrated and sustainable water resource management in semi-arid regions.

How to cite: Esteve, P., Blanco-Gutiérrez, I., Mautner, M. R., Seifollahi-Aghmiuni, S., and Escobar, M.: Challenges and opportunities of using reclaimed water for agricultural irrigation in Spain: A hydro-economic analysis. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3533, https://doi.org/10.5194/egusphere-egu24-3533, 2024.

EGU24-3941 | ECS | Orals | ERE1.5 | Highlight

Do non-conventional water resources lead to a better performance of irrigation communities? A comparative analysis between the regions of Murcia (Spain) and Apulia (Italy) 

Mario Ballesteros-Olza, Sarah Stempfle, Irene Blanco-Gutiérrez, Almudena Gómez-Ramos, Giacomo Giannoccaro, and Bernardo De Gennaro

In a context of growing global water demands, plus climate change affecting water resources availability, non-conventional water sources (like reclaimed water and desalinated seawater) are emerging as promising water supply alternatives. Given that agriculture is the major contributor to water withdrawals, this study analyzes if the use of non-conventional water for irrigation leads to a better performance of irrigation communities (ICs). To do so, the research includes several ICs from the Segura River Basin (southeast of Spain), a region with structural water deficit, which is pioneer regarding the use of non-conventional water; as well as ICs from the Apulia region (southeast of Italy), which also suffers from water scarcity problems, but is less experienced regarding the use of non-conventional water. A benchmarking analysis was carried out, based on a set of Key Performance Indicators (KPIs), such as irrigation efficiency, guarantee of water supply, energy costs or gross margin, among others. This methodology has been previously used in the framework of the water and drainage sector. Also, a Principal Component Analysis and Clustering Analysis were applied to explore potential dissimilarities between the studied ICs and their causes. Finally, a regression analysis was carried out to observe if the use of non-conventional water has any effects on the performance of the studied ICs. The results of this research may help to increase knowledge regarding the pros and cons of using these non-conventional water resources, depending on the socioeconomic, environmental and geographical context. This way, this study would contribute to promoting the use of non-conventional water in other regions, leaning towards a more sustainable use of water resources and, consequently, protecting and preserving water ecosystems.

How to cite: Ballesteros-Olza, M., Stempfle, S., Blanco-Gutiérrez, I., Gómez-Ramos, A., Giannoccaro, G., and De Gennaro, B.: Do non-conventional water resources lead to a better performance of irrigation communities? A comparative analysis between the regions of Murcia (Spain) and Apulia (Italy), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3941, https://doi.org/10.5194/egusphere-egu24-3941, 2024.

EGU24-4136 | ECS | Orals | ERE1.5 | Highlight

The economic and environmental impacts of UK meat imports post-Brexit 

Kaixuan Wang, Lirong Liu, Jonathan Chenoweth, and Stephen Morse

The United Kingdom (UK), a high consumer of meat, has traditionally relied heavily on the European Union for its meat imports. However, with the advent of Brexit, the UK now faces the imperative of identifying potential meat-importing nations. The choices of different meat import countries not only impact the economy and environment of the UK but also other countries around the world. This study builds the UK Meat Trade-centred World Input-Output Model (UK-MTWIO), incorporating diverse import data within various scenarios. With different scenarios considering costs, GHG emission and animal welfare, this study analyzes the economic, environmental and animal welfare impacts on the UK and other countries worldwide. The novelty involves the comprehensive consideration of scenario setting, the application of RAS method as well as the animal welfare analysis with the method of world input-output model. The study reveals that beef imports have the most significant impact on the imports of the lamb and pork. Meanwhile, the changes in the UK's meat trade may change the trade partners of some major meat-importing countries. In terms of environment, some import scenarios have the potential to contribute to GHG emissions reduction in the global agricultural sector: CHN, MEX, and JPN are typical countries that are significantly impacted. The results of this study provides valuable insights for policymakers making meat trade decisions post-Brexit.

How to cite: Wang, K., Liu, L., Chenoweth, J., and Morse, S.: The economic and environmental impacts of UK meat imports post-Brexit, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4136, https://doi.org/10.5194/egusphere-egu24-4136, 2024.

EGU24-5637 | ECS | Orals | ERE1.5

Balancing food system greenhouse gas emissions reduction and food security in China 

Hao Zhao, Haotian Zhang, Petr Havlik, and Jinfeng Chang

China's increasing food consumption, particularly for animal products, presents a substantial challenge to mitigating greenhouse gas (GHG) emissions, not only within China but also extending to its trading partners. In this study, we employ the well-established food system integrated assessment model (GLOBIOM-China) to comprehensively investigate GHG emissions within the context of China's future food consumption. Our study indicates that in the baseline scenario (BAU), GHG emissions from China's food consumption side are projected to be 965 million tonnes of CO2 equivalent (Mt CO2 eq) by 2060, similar to the current level. Domestically, ruminant production accounts for a substantial 44% of total consumption-based emissions. Meanwhile, livestock-related methane emissions take prominence in terms of different gas categories, comprising a significant 45%. Virtual GHG emissions import is expected to decrease due to the deceleration of land use change, while the GHG emissions attributable to livestock product imports are projected to incrementally rise, eventually constituting 17.2% of the total food consumption-based emissions. Striving for food self-sufficiency (SS scenario) offers a pathway to diminishing China's food system GHG emissions and virtually imported emissions by 6% and 43%, respectively. However, this scenario presents an increase of domestic emissions by 2% and simultaneously poses challenges to domestic land use and other related indicators. Maintaining basic food self-sufficiency, and reducing calorie intake from animal sources and improving production practices contribute to a 216 Mt CO2eq reduction of total GHG emissions. This approach not only holds promise for emission reduction but also brings broader benefits such as decreased agricultural commodity prices (by -28%), reduced nitrogen fertilizer uses (by -13%), diminished agricultural land requirement (by -10%), and only 2% decline in per capita calorie intake. Our study reconciles GHG mitigation strategies and food security within China's food system, thereby contributing significantly to global sustainable development.

How to cite: Zhao, H., Zhang, H., Havlik, P., and Chang, J.: Balancing food system greenhouse gas emissions reduction and food security in China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5637, https://doi.org/10.5194/egusphere-egu24-5637, 2024.

EGU24-7331 | ECS | Orals | ERE1.5

Agricultural pollution in Indian Interstate Trade Network 

Shekhar Goyal, Raviraj Dave, Udit Bhatia, and Rohini Kumar

Humanity’s contemporary challenge in achieving global food security is sustainably feeding the rising global population. Intensive agricultural practices have powered green revolutions, helping nations attain self-sufficiency. However, these fertilizer-intensive methods and exploitative trade systems have created unsustainable agrarian systems. To probe the environmental consequences on production hubs, we map the fate of Nitrogen and Phosphorus in India’s interstate staple crop trade over the recent decade. Here, we analysed the spatiotemporal evolution of physical and virtual nutrient flow within India's interstate agricultural trade network, examining the environmental load on key production regions, assessing the sustainability of domestic wheat and rice trade systems in light of nutrient surplus, and providing policy recommendations for environmentally sustainable food security. Our examination of the cereal crop trade reveals that the Nation's food bowls contributing significantly towards domestic food security are sacrificing their environmental goals by becoming pollution-rich and water-poor. Our study emphasises policies focusing on redistributing funds from agricultural subsidies that aggravate environmental disparity to those incentivising sustainable production. The findings could offer a foundation for designing and exploring alternate trade network configurations that aim for environmental sustainability without compromising food security goals.

 

How to cite: Goyal, S., Dave, R., Bhatia, U., and Kumar, R.: Agricultural pollution in Indian Interstate Trade Network, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7331, https://doi.org/10.5194/egusphere-egu24-7331, 2024.

EGU24-7380 | ECS | Orals | ERE1.5

Removal of favipiravir and oseltamivir in domestic wastewater effluents using ozonation and catalytic ozonation 

Nasim Chavoshi, Serdar Dogruel, Nilay Bilgin-Saritas, Zeynep Karaoglu, Irem Ozturk-Ufuk, Ramazan Keyikoglu, Alireza Khataee, Emel Topuz, and Elif Pehlivanoglu-Mantas

The surge in pharmaceutical use during global pandemics, like SARS-CoV-2, has led to increased antiviral concentrations in wastewater treatment plant influents. The low biodegradability of certain antivirals poses a challenge for wastewater treatment, threatening aquatic and soil ecosystems. This study aimed to optimize ozonation and catalytic ozonation processes for removing two anti-COVID-19 drugs (namely, favipiravir and oseltamivir) and assess their ecotoxicological effects in the context of potential wastewater reuse.

In this study, samples with 50 µg/L of favipiravir and oseltamivir were added to synthetic wastewater with approximately 50 mg COD/L, mirroring a typical domestic effluent. Experiments involved three ozone doses (0.2, 0.6, and 1 mg O3/mg DOC) at pH levels of 7 and 10. Adding 0.1 g/L of ZnFe layered double hydroxide as a catalyst aimed to improve the ozonation efficiency. Samples with 0.1 mg/L polyethylene microplastics were prepared to explore the efficiency of the applied processes in the presence of microplastics. The target drugs were quantified by LC-MS/MS. E. crypticus was used to understand the ecotoxicological impact of the treatment techniques on the potential reuse of treated wastewater for irrigation.

Regardless of the ozone dose used, ozonation at pH=7 resulted in removal efficiencies of 84% and 64% for favipiravir and oseltamivir, respectively. Increasing the pH value to 10 did not improve favipiravir elimination, yet an additional removal of 21% was recorded for oseltamivir at all three ozone doses. During catalytic ozonation, an approximately 30% decline in the abatement of drugs was observed when compared with ozonation alone, which could be attributed to either adsorption of ozone on the catalyst’s active-sites (blockage of active-sites and reduction in the availability of ozone radicals) or production of refractory by-products (enhancement in the competition between radicals and active-sites). In the presence of microplastics, ozonation experiments at pH=7 provided an average decrease of about 30% in the removal efficiency for both drugs whereas ozonation at pH of 10 resulted in an approximately 15% fall in the elimination level. Catalytic ozonation in the absence of microplastics, however, showed positive effects on the reduction rates of the examined drugs since the applied process yielded an improvement in the abatement of 14 and 7% for favipiravir and oseltamivir, respectively. Both in the presence and absence of microplastics, ozonation and catalytic ozonation of antivirals at pH=7 did not lead to any toxic effects for the reproduction of E. crypticus; instead, an increase in the reproduction performance was found, possibly due to the formation of more biodegradable organic intermediates. The experimental data obtained revealed that ozonation or catalytic ozonation could be viable alternatives for upgrading the existing wastewater treatment plants as they functioned well as a complementary treatment process not only to reduce the release of antivirals from domestic effluents, but also to substantially increase the reuse potential of treated wastewater for irrigation purposes.

This study was financially supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project #121Y383) and Scientific Research Projects Coordination Unit of Istanbul Technical University (ITU-BAP, Project # MYL-2023-44496).

How to cite: Chavoshi, N., Dogruel, S., Bilgin-Saritas, N., Karaoglu, Z., Ozturk-Ufuk, I., Keyikoglu, R., Khataee, A., Topuz, E., and Pehlivanoglu-Mantas, E.: Removal of favipiravir and oseltamivir in domestic wastewater effluents using ozonation and catalytic ozonation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7380, https://doi.org/10.5194/egusphere-egu24-7380, 2024.

EGU24-7458 | ECS | Orals | ERE1.5 | Highlight

Leveraging renewable energy solutions for distributed urban water management: The case of sewer mining 

Athanasios Zisos, Klio Monokrousou, Konstantinos Tsimnadis, Ioannis Dafnos, Katerina Dimitrou, Andreas Efstratiadis, and Christos Makropoulos

As urban populations swell and infrastructure demands escalate, managing resources sustainably becomes increasingly challenging. This paper focuses on the energy challenges inherent in distributed water management systems, using sewer mining as an example. Sewer mining is a distributed water management solution involving mobile wastewater treatment units that extract and treat wastewater locally. In this context, we examine the integration of renewable energy sources, specifically solar photovoltaics, to reduce reliance on traditional power grids, highlighting a pilot implementation at the Athens Plant Nursery in Greece since 2021. The study evaluates various system configurations, balancing performance with landscape integration, to propose a scalable and robust model for distributed water management. This approach not only addresses the direct energy requirements of water treatment systems but also contributes to the broader agenda of circular economy, by enhancing the sustainability and resilience of urban water infrastructure.

This work is supported by IMPETUS research project that has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 101037084

How to cite: Zisos, A., Monokrousou, K., Tsimnadis, K., Dafnos, I., Dimitrou, K., Efstratiadis, A., and Makropoulos, C.: Leveraging renewable energy solutions for distributed urban water management: The case of sewer mining, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7458, https://doi.org/10.5194/egusphere-egu24-7458, 2024.

EGU24-7880 | ECS | Orals | ERE1.5

Crop switching in the Indo-Gangetic Plain of India can improve water and food sustainability with increased farmers’ profit 

Ruparati Chakraborti, Kyle Frankel Davis, Ruth DeFries, Narasimha D. Rao, Jisha Joseph, and Subimal Ghosh

Water and food security in the Indo-Gangetic Plain (IGP) is severely affected due to the intensive irrigated agriculture, growing population, and changing climate. Agricultural intensification with the water-intensive rice-wheat system has increased the water demand in India. The declining monsoon rainfall and increased irrigation with more reliance on groundwater sources have resulted in groundwater depletion over India’s fertile region, the Indo-Gangetic Plain (IGP), with high energy usage. Despite several agricultural technology developments, no improvement is found in calorie production from cereal crops per unit of water consumption in the IGP. Crop switching from water-intensive rice and wheat to climate-resilient nutri-cereals can be a potential solution for water sustainability, but other dimensions i.e. food supply, and farmers’ profit need to be considered for implementation. So, a multi-objective optimization framework is needed to address the social, economic, and environmental sustainability objectives which are conflicting in nature, to find the optimal cropping pattern. In this study, an optimization model is developed and applied for crop switching with objectives to maximize calorie production, and farmers’ profit and to minimize water consumption by reallocating the cropped areas between cereals at the district level. Application of the model suggests switching from rice to millet and sorghum in the Kharif Season (monsoon), and wheat to sorghum and barley in the Rabi season (winter), which could potentially decrease water consumption by 32%, increase calorie production by 39%, and elevate farmers' profits by 140%. Water and energy savings (with the replaced cropping pattern are higher than changing irrigation practices (i.e. from flood to drip). So, crop switching coupled with efficient irrigation practices (drip) contributes to saving more energy and water. These findings suggest the potential of crop switching to address the multidimensional sustainability challenges in agricultural practices in the IGP, with a scope of application to other regions grappling with similar issues. The implementation of crop switching is driven by multiple factors such as the willingness of farmers, incentives, and other strategies for farmers to shift crop practice, procurement of nutri cereals through Minimum Support Price, subsidized supply through the Public Distribution System, and consumer demand; thus, leaving an opportunity to explore these aspects in future studies for policy framing towards sustainable agricultural practices.

How to cite: Chakraborti, R., Davis, K. F., DeFries, R., D. Rao, N., Joseph, J., and Ghosh, S.: Crop switching in the Indo-Gangetic Plain of India can improve water and food sustainability with increased farmers’ profit, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7880, https://doi.org/10.5194/egusphere-egu24-7880, 2024.

EGU24-9881 | ECS | Posters on site | ERE1.5

Comparison of different interpolation techniques for sub-basins located in Madrid. 

Blanca Cuevas, Elena Pascual, Carlota Bernal, and Sergio Zubelzu

Soil hydrophysical properties can be very spatially and temporally heterogeneous even in small areas. Due to this spatial and temporal variability, it is impossible to obtain real data for each point of interest. Therefore, the possibility to obtain the optimal estimated value, at any desired point, is decisive. The aim is to evaluate different methods to minimise the error made in this measurement.

Two basins were selected in the Autonomous Community of Madrid (Spain), where hydraulic conductivity data were taken at different points. All sampling point in both basins were georeferenced. For each basing different interpolation methods were tested. The methods used are Spline, Inverse Distance Weighted Interpolation (IDW), Kriging, and Thiessen Polygons. With the help of the Matlab program, the values for each method were obtained. Finally, the error is used for the analysis.

Differences among the obtained data by each method are expected to be found. In addition to the differences between the number of samples and the error, and the location in the basin of the samples.

In conclusion, it is hoped to find the most appropriate method for obtaining a value as close to reality as possible. Furthermore, it is expected to be able to use this methodology in other situations.

Acknowledgements: This research Project has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid

How to cite: Cuevas, B., Pascual, E., Bernal, C., and Zubelzu, S.: Comparison of different interpolation techniques for sub-basins located in Madrid., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9881, https://doi.org/10.5194/egusphere-egu24-9881, 2024.

EGU24-11353 | ECS | Orals | ERE1.5

Agroforestry management practices as nature-based solutions for climate change adaptation in the Galapagos Islands 

Ilia Alomia, Yessenia Montes, Rose Paque, Jean Dixon, Armando Molina, and Veerle Vanacker

Small tropical islands in the Pacific Ocean are highly vulnerable to climate change. Nature-based solutions can help local communities adapt their local agricultural systems. Through a comparative analysis, we evaluated the effects of agroforestry management practices on soil temperature, soil water availability and storage, and carbon stocks in Santa Cruz Island (Galapagos Archipelago). We installed six monitoring sites that consist of two replicates per agroforestry management practices: (i) conservation of native forest, (ii) traditional agroforestry, and (iii) abandoned farmland in passive restoration. After pedological characterization of the sites, the soil physicochemical and hydrological properties were determined in the laboratory. Over 30 months (July 2019 to December 2021), the environmental sensors captured the hydrometeorological and soil physical and hydrological properties of the sites. This was done by a dense network of rain gauges, air temperature and relative humidity sensors, and time-domain reflectance probes that registered volumetric water content and soil temperature.

We measured differences in soil temperature, moisture availability and soil organic carbon content between soils under forest, traditional agroforestry and passive restoration. Forest soils are protected from direct solar radiation, and trees keep the soil 12% cooler than soils converted to agricultural land. Soil moisture is 20% higher under forest than under traditional agroforestry or abandoned farmland, and forest soils have a lower dry bulk density, lower saturated hydraulic conductivity and higher water retention capacity. The forests and sites under passive restoration store more than 377 Mg C. ha-1 (1 m depth), about 50% more than under traditional agroforestry. The study shows that conserving forest patches in an agricultural landscape might be a promising strategy to mitigate increasing soil temperatures, agricultural drought, and decline in soil organic carbon content. However, more studies on landscape scale are needed to corroborate those results.

How to cite: Alomia, I., Montes, Y., Paque, R., Dixon, J., Molina, A., and Vanacker, V.: Agroforestry management practices as nature-based solutions for climate change adaptation in the Galapagos Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11353, https://doi.org/10.5194/egusphere-egu24-11353, 2024.

EGU24-11369 | ECS | Orals | ERE1.5

Expert-based global database of sand dams dimensions and distribution across drylands 

Jessica Eisma, Luigi Piemontese, Giulio Castelli, Ruth Quinn, Bongani Mpofu, Doug Graber Neufeld, Cate Ryan, Hannah Ritchie, Lorenzo Villani, and Elena Bresci

Sand dams are water harvesting structures built across ephemeral sandy rivers to increase water supply in drylands. Despite their effectiveness in reducing water scarcity for local communities and their recent traction in research and development, information on their distribution and characteristics are sporadic and largely unreported. This gap represents a major barrier for understanding the large-scale potential of such a Nature-based Solution for drylands and planning for new infrastructure. This paper presents a global database of sand dam locations and dimensions developed within a collaboration between research and development experts on the topic. We collected sand dam information on location from several sources, ranging from research reports to databases provided by practitioners. We then reviewed and enriched them based on visual inspection from Google Earth images. The georeferenced information provided by the database can support research development on the effectiveness of sand dams and support practitioners with science-based criteria for sand dam development across global drylands.

How to cite: Eisma, J., Piemontese, L., Castelli, G., Quinn, R., Mpofu, B., Graber Neufeld, D., Ryan, C., Ritchie, H., Villani, L., and Bresci, E.: Expert-based global database of sand dams dimensions and distribution across drylands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11369, https://doi.org/10.5194/egusphere-egu24-11369, 2024.

Pumping energy is a key component of the groundwater governance challenge. Yet it is largely missing in the discourse on agricultural use of groundwater. A sub-category of literature studying groundwater-energy nexus tends to focus on groundwater depletion hotspots where entrenched interests and long-standing history restrict the range of feasible energy models. We simulate expected impacts of expanding groundwater irrigation under five different energy provision models in a region with among the lowest irrigation coverage, and therefore, free of path dependent policies. We find aquifer properties play a crucial role in mediating the groundwater-energy nexus. On average, the maximum volume of water that can be pumped from a well of a specific depth in an alluvial aquifer is approximately 150 times the volume that can be pumped from a well in a hard-rock aquifer. Therefore, managing uncertainty in groundwater consumption is a far greater challenge in alluvial than hard-rock aquifers. Uncertainty in groundwater consumption can be limited in hard-rock aquifers if the number of wells and depths of wells can be controlled - capital subsidies for well construction could be a potential policy. Our results imply that while solar pumps are a risky alternative in alluvial aquifers for maintaining current and future groundwater levels, they are relatively safe and among the most economical for expanding irrigation in hard-rock regions. Using a novel dataset comprising of biophysical and socioeconomic data, we find hard-rock regions to have limited irrigation coverage, high availability of annually replenishable groundwater, and high concentrations of marginalized farmers. Therefore, groundwater irrigation expansion in hard-rock areas could have dual benefits of ensuring future food security and targeting poverty reduction.

How to cite: Ray, S.: Balancing groundwater access and sustainability through energy pricing in India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13972, https://doi.org/10.5194/egusphere-egu24-13972, 2024.

EGU24-14721 | Posters on site | ERE1.5

Silage  production from olive mil wastes  

Ioannis Manariotis, Styliani Biliani, Maria Varvara Manarioti, and Nikolaos Athanassolpoulos

Within the European Union, approximately 129 Mtons of food waste were generated in 2011, and about 52% of them derived from post-processing activities. The most common by-products originated from the food industry are spent coffee grounds, sugar cane waste, and fruit peels, while the main agricultural wastes are livestock slurry, manure, crop residue, and woodland pruning and maintenance wastes. The olive tree is cultivated worldwide, and more than 90% of the cultivated area is located in the Mediterranean basin. The olive oil extraction is carried out using two- or three-phase centrifuge systems. The olive mill wastes can be incorporated into the diets of productive animals, especially ruminants, due to their high fiber content. The aim of this work was to investigate the optimum conditions for silage production for animal food using olive oil wastes from a diphasic olive mill facility. Olive mill waste and straw were the base materials for silage composition: 53 to 55% and 45 to 47%, respectively (dry weight basis). Different mass ratios of molasse (0 to 4%) and urea (0 to 1%) per olive mill mass (dry weight) were used. The presence of urea and the absence of molasses turned out to be inhibitory factors for the silage process. The highest molasses rates the highest efficiency of silage production.

How to cite: Manariotis, I., Biliani, S., Manarioti, M. V., and Athanassolpoulos, N.: Silage  production from olive mil wastes , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14721, https://doi.org/10.5194/egusphere-egu24-14721, 2024.

EGU24-14983 | ECS | Orals | ERE1.5 | Highlight

Reducing climate change impacts and inequality of the global food system through diet shifts 

Yanxian Li, Pan He, Yuli Shan, Yu Li, Ye Hang, Shuai Shao, Franco Ruzzenenti, and Klaus Hubacek

How much and what we eat and where it is produced can create huge differences in greenhouse gas emissions. Bridging food consumption with detailed household-expenditure data, this study estimates dietary emissions from 13 food categories consumed by 201 expenditure groups in 139 countries, and further models the emission mitigation potential of worldwide adoption of the EAT–Lancet planetary health diet. We find that the consumption of groups with higher expenditures generally creates larger dietary emissions due to excessive red meat and dairy intake. As countries develop, the disparities in both emission volumes and patterns among expenditure groups tend to decrease. Global dietary emissions would fall by 17% if all countries adopted the planetary health diet, primarily attributed to decreased red meat and grains, despite a substantial increase in emissions related to increased consumption of legumes and nuts. The wealthiest populations in developed and rapidly developing countries have greater potential to reduce emissions through diet shifts, while the bottom and lower-middle populations from developing countries would cause a considerable emission increase to reach the planetary health diet. Our findings highlight the opportunities and challenges to combat climate change and reduce food inequality through shifting to healthier diets.

How to cite: Li, Y., He, P., Shan, Y., Li, Y., Hang, Y., Shao, S., Ruzzenenti, F., and Hubacek, K.: Reducing climate change impacts and inequality of the global food system through diet shifts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14983, https://doi.org/10.5194/egusphere-egu24-14983, 2024.

EGU24-15307 | ECS | Orals | ERE1.5

Tracking real-time impacts of climate variability and trade disruptions on water and food security  

Marijn Gülpen, Christian Siderius, Ype van der Velde, Jon Cranko Page, Jan Biermann, Ronald Hutjes, Lisanne Nauta, Samuel Sutanto, and Hester Biemans

Food insecurity results from a complex interplay of climate, socio-economic and political drivers, with local food security being frequently influenced by events elsewhere. Recent unprecedented climate events and economic disruptions such as Covid-19 and the resurgence of large intra- and inter-state conflict, show the diverse and unpredictable nature of risk, which can suddenly impacting food production and supply chains.

Here, we present a coupled hydrology-crop production-trade model that is able to simulate, in real time, current and near-future risks to water and food security. The model combines an operational process-based simulation of global crop production and hydrology with an ML-powered trade module, trained on FAOs detailed trade matrix dataset. It is updated monthly with the latest ERA5 climate data from the Copernicus Data Store to assess current risk, and can be forced with seasonal forecasting and long term climate projections up to 2100. The model explains about 50% of yield variability in major growing regions - a critical characteristic for nowcasts or seasonal forecasts – and the majority of food trade and trends therein, but generally still underestimates the variability. As a first step to better reproduce observed crop yield anomalies we improved the simulation of growing seasons in the production model.  

By combining production with trade, we are able to estimate the impact of climate-related yield anomalies elsewhere, and to assess risks for water- and food security at the country, regional or global scale. Derived indicators provide a real-time insight into, for example, food production and storage per capita, crop water productivity, or crop or export specific water stress. Through continued evaluation and learning, we expect to be able to better identify emerging stresses in the food system and its drivers, and support early anticipation of potential future food security risks. This should ultimately lead to a better understanding of the complexity of the global food system and eventually result in a more sustainable food system.

How to cite: Gülpen, M., Siderius, C., van der Velde, Y., Cranko Page, J., Biermann, J., Hutjes, R., Nauta, L., Sutanto, S., and Biemans, H.: Tracking real-time impacts of climate variability and trade disruptions on water and food security , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15307, https://doi.org/10.5194/egusphere-egu24-15307, 2024.

EGU24-15345 | ECS | Orals | ERE1.5

Atrazine Removal in Constructed Wetlands: Efficacy of Monocultures versus Polycultures 

Sai Kiran Pilla, Mahak Jain, Partha Sarathi Ghosal, and Ashok Kumar Gupta

The Green Revolution in India, from 1967-68 to 1977-78, led to a significant shift in the country's agricultural landscape, transforming it from an insufficient food production country to a global agricultural power. This led to an increase in the use of pesticides, such as atrazine, which can pollute water sources and endanger aquatic habitats. This research aims to find sustainable and practical techniques for atrazine remediation within aquatic habitats. Literature suggests that macrophyte richness enhances the functionality of constructed wetlands (CWs), but the predominant practice is monocultures. The functional diversity within macrophyte communities is crucial for optimal performance of CWs for contaminant remediation. CWs with diverse growth forms exhibit enhanced plant growth and superior nutrient removal capabilities. The study evaluates atrazine removal efficacy of polyculture and monoculture plantation, monitoring the efficiency of various individual macrophyte, such as Canna indica and Phragmites Australis for atrazine detoxification. The findings could guide the formulation of sustainable and efficacious atrazine remediation strategies, safeguarding water quality and the integrity of aquatic ecosystems.

How to cite: Pilla, S. K., Jain, M., Ghosal, P. S., and Gupta, A. K.: Atrazine Removal in Constructed Wetlands: Efficacy of Monocultures versus Polycultures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15345, https://doi.org/10.5194/egusphere-egu24-15345, 2024.

EGU24-16795 | ECS | Posters on site | ERE1.5 | Highlight

Food loss & waste of staple crop products: mapping environmental impacts within the Nexus paradigm 

Francesco Semeria, Giacomo Falchetta, Adriano Vinca, Francesco Laio, Luca Ridolfi, and Marta Tuninetti

Over the last decade, a combination of economic uncertainty, supply shocks, and extreme climate events has led to a renewed prevalence of undernourishment, posing a serious threat to the realization of the Zero Hunger Sustainable Development Goal. Future scenarios are likely to be even more challenging to its accomplishment, based on projected trends of population growth and human-induced climate change impacts. There is urgent need for the development and implementation of sustainable transformation pathways to make agri-food systems worldwide more resilient and capable to sustain these pressures. These pathways should include a wide range of actions, targeting all stages of the value chain. Reducing food loss and waste (FLW), which currently accounts for approximately one-third of the food produced, is considered among those with the largest potential, with significant environmental co-benefits on the Water-Energy-Food-Ecosystem Nexus. The presence of complex and tele-coupled trade networks however, together with the lack of robust and granular datasets, make it difficult for researchers to run detailed analyses on this issue.

In this work we estimate the FLW associated to the consumption of a wide range of staple crops globally, disaggregating between the single food commodities and the different stages of the value chain. Moreover, we investigate the associated impacts on the water, land, and energy resources. The methodology applied allows us to trace the environmental impacts from the countries of production and manufacturing, where resources have been used, to the countries of consumption (from farm to fork) and backwards (from fork to farm), offering a dual perspective on the complex system. Our preliminary results show that over 20% of the quantities cultivated are wasted through FLW, globally. Transnational flows of FLW – and of associated virtual resources – compose a vast multi-layered network involving most of the countries worldwide. Differentiated impacts are observed, depending on the countries’ role in the network: while large exporters bear substantial impacts of FLW occurring abroad on their resources, net-importing nations transfer large portions of the environmental effects of the FLW associated with their consumptions onto foreign stocks. The ability to discern between the single food commodities, without aggregating primary and derived products, increases the level of specificity from past research. This detailed data is valuable for informing public policies, providing a more fine-grained approach to prioritize efforts in reducing FLW and its associated impacts.

How to cite: Semeria, F., Falchetta, G., Vinca, A., Laio, F., Ridolfi, L., and Tuninetti, M.: Food loss & waste of staple crop products: mapping environmental impacts within the Nexus paradigm, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16795, https://doi.org/10.5194/egusphere-egu24-16795, 2024.

EGU24-18001 | ECS | Orals | ERE1.5

Adsorptive removal of humic acid from water by magnesium oxide 

Rupal Sinha and Partha Sarathi Ghosal

Disinfection is a critical drinking water treatment procedure to guarantee water safety in urban water supply systems. However, an inevitable consequence is the generation of secondary pollutants, referred to as disinfection byproducts (DBPs). Toxicological researches have linked the ingestion of DBPs to harmful human health consequences like a higher risk of bladder cancer, reproductive problems, etc. Subsequently, the water authorities face immense challenges due to their existence in the drinking water. The foremost approach to limiting their generation in the drinking water is to eliminate their precursors prior-to disinfection. Humic acid (HA), a significant constituent of the natural organic matter in surface water, has been acknowledged as the primary precursor of DBPs. Thus, the present work aims to reduce humic acid content in water by magnesium oxide (MgO) adsorbent. To ascertain the mechanism of humic acid removal, characterizations of the adsorbents were conducted both before and after. At neutral pH level, the impacts of various process parameters are examined, including contact time, adsorbent dosage, initial humic acid concentration, and temperature. Moreover, studies were performed to assess the effects of different solution pH on the elimination of humic acid. The removal of humic acid was found to be increased at low pH. At pH 3, over 85% elimination was obtained. Furthermore, the role of several anions, including nitrate, sulfate, and chloride, in the adsorption of humic acid has also been evaluated. Overall, the present study would be conducive to proving the applicability of MgO for the reduction of HA and other organic matter from water and, hence, reduce the generation of DBPs.

How to cite: Sinha, R. and Ghosal, P. S.: Adsorptive removal of humic acid from water by magnesium oxide, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18001, https://doi.org/10.5194/egusphere-egu24-18001, 2024.

Life Cycle Assessment (LCA) is a systematic approach used to evaluate the environmental impacts of products, services, or activities throughout their life cycle, from raw material acquisition and production to use and final disposal or recycling stages. The goal of LCA is to comprehensively assess environmental impacts across the entire life cycle, including energy consumption, greenhouse gas emissions, water and land use, and more. The execution of LCA primarily involves four stages: "goal and scope definition," "life cycle inventory," "life cycle impact assessment," and "life cycle interpretation." This method helps identify and improve environmental hotspots in products or activities, aiming to reduce adverse impacts on the environment.

This study references the "Packaging Lunch Box Product Category Rules" published by the Environmental Protection Administration of the Executive Yuan in Taiwan. Using a vegetarian lunch box manufacturer in Taiwan as a data source, a "Vegetarian Lunch Box Carbon Footprint Calculation Tool" was developed using SimaPro. Users can input first-tier data for each stage of the product life cycle (such as raw material input, energy, transportation distance, and output products), enabling the calculation of the carbon footprint of the vegetarian lunch box.

However, during the "life cycle interpretation" stage, this study found that the "raw material acquisition stage" contributes 80% of the carbon footprint throughout the entire life cycle of the vegetarian lunch box. This indicates significant negative environmental impacts during the "agricultural production" process. As a result, the study traces the environmental impacts of upstream agricultural production processes for grains and vegetables and proposes an improvement strategy: regenerative agriculture.

Regenerative agriculture practices include protective tillage to reduce physical soil disturbance, increasing biodiversity in fields, cover cropping to enhance soil carbon and prevent erosion, crop rotation for balanced soil nutrient use, and refraining from using chemical fertilizers and pesticides. The goal of regenerative agriculture is to sequester carbon in the soil and above-ground biomass, reducing greenhouse gas emissions, increasing crop yields, enhancing resilience to unstable climates, and improving the health and vitality of rural communities.

This study will also employ the life cycle assessment method to collect inputs and outputs for both conventional farming practices and regenerative agriculture, comparing their environmental impacts.

How to cite: Chen, C.-K. and Tung, C.-P.: Application of Life Cycle Assessment in Vegetarian Lunch Box: Environmental Impact Hotspot Analysis of Whole Grain and Vegetable Production, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18099, https://doi.org/10.5194/egusphere-egu24-18099, 2024.

EGU24-20605 | ECS | Posters on site | ERE1.5

Exploring the potential of cowpea inoculation in Namibia for improved resource use and human nutrition 

Jihye Jeong, Kerstin Jantke, and Uwe. A Schneider
  • Motivation, problem statement and aim

Cowpea is an important source of protein in the semiarid parts of sub-Saharan Africa. Even under water or temperature stress, cowpea can produce grain and fix nitrogen. The robustness of cowpea makes them a good choice especially for smallholder farmers with limited resource. Inoculated cowpea is not only more resilient against many plant diseases, but also can fix nitrogen more effectively.

Located in sub-Saharan region, water supply is a constant struggle of Namibia. In addition, due to dry climate and soil characters, only 1% of the country is arable. In contrast to harsh natural condition, over 70% of population depends their livelihoods on agriculture. For insufficient production, food supply in Namibia is highly dependent on imports. This combination of natural and societal condition puts Namibian population into nutrition hazard.

Thereby, the study aims to investigate the potential of cowpea inoculation in Namibia by answering the following questions:

1) How much can inoculation increase cowpea production in Namibia?

2) How much land and water resource can be saved by introducing inoculation in cowpea cultivation?

  • Methodology

Environment Policy and Integrated Climate (EPIC) model is adopted for crop simulation. It is calibrated specifically to the Namibian agricultural environment. Different climate scenarios and agricultural management systems are simulated in EPIC. The simulation result is used in optimisation modelling using General Algebraic Modelling System (GAMS). The model is simulated under objective of maximum food production given the current population.

  • Result

Primarily, potential cowpea production is depicted in both inoculated and non-inoculated scenarios. The simulation considers the total arable land of the country and subsistence farming as the only farming management. Cowpea production increases by 26% with inoculation.

The land and water use of inoculated cowpea cultivation is shown in relative to non-inoculated cowpea cultivation. In the perspective of current resource availability, the relative resource use is elaborated. Inoculation saves up to 23% of land and 79% of water use.

  • Conclusion

By introducing inoculation in cowpea cultivation, Namibia is expected to have meaningful increase in production and decrease in both land and water use. Since cowpea is already well integrated in smallholder farmers’ practice, the adoption of inoculation can penetrate the positive effects into remote and vulnerable areas.

How to cite: Jeong, J., Jantke, K., and Schneider, Uwe. A.: Exploring the potential of cowpea inoculation in Namibia for improved resource use and human nutrition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20605, https://doi.org/10.5194/egusphere-egu24-20605, 2024.

EGU24-21484 | Orals | ERE1.5

Sustainable and digitalized water management in rural environments in the SUDOE area (GestEAUr project) 

Jose Luis Molina, Victor Monsalvo, Angel Encinas, and Engracia Lacasa

The rural areas of the SUDOE present many common challenges related to the integrated water cycle: the scarcity of water resources (aggravated by climate change), the impact of agricultural and livestock activities on water quality (and the consequent difficulty of reconciling compliance with the European directive, the continuity of economic activity and the availability of water) and the lack of efficiency and profitability in management (with obsolete facilities and few human resources).
It is essential to strengthen collaboration networks between the many stakeholders involved in water resources management in order to implement efficient, sustainable and cost-effective techniques for water purification, reuse and treatment. To this end, it is necessary to create a new governance system based on territorial cooperation. Water is a common good and, as such, it does not understand borders.
The project will develop a strategy to improve water efficiency and quality in rural SUDOE areas in a context of climate change, 5 action plans for 4 organizations to improve water supply and treatment services, 3 pilot tests of cost-effective and sustainable solutions for water purification, purification and reuse, and a digital tool for 2 organizations to improve water management. In addition, it will improve the capacities of public authorities in 3 countries and the knowledge of water purification, treatment and reuse techniques like water treatment, reuse and purification techniques of 3 scientific institutions.
GestEAUr will adopt an innovative approach, addressing the integrated water cycle holistically (taking into account all its stages) and will go beyond existing practice, which tends to apply the same solutions whatever the characteristics of the territory where they are implemented.
Consequently, it will analyze and test cost-effective, cutting-edge and nature-based techniques (and combinations of techniques) (SBN) specific to the needs of rural areas in the SUDOE. It will also provide digital tools to optimize and facilitate their management and planning.

How to cite: Molina, J. L., Monsalvo, V., Encinas, A., and Lacasa, E.: Sustainable and digitalized water management in rural environments in the SUDOE area (GestEAUr project), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21484, https://doi.org/10.5194/egusphere-egu24-21484, 2024.

EGU24-1146 | ECS | Orals | ERE1.6

Mitigation of GHG emission from the wastewater treatment plant: Life cycle assessment approach 

Praveen Kumar Vidyarthi, Pratham Arora, Nadège Blond, and Jean-Luc Ponche

The rapid expansion of wastewater treatment plants, aimed at mitigating global water stress, has significantly increased the energy demand. In India, the anticipated rise in sewage generation to treatment ratio from 46% to 80% by 2050 [1]. It is expected to further intensify the energy demand of treatment facilities to meet national standards. This required energy, predominantly in the form of electricity, primarily fulfill from coal-based thermal plants, consequently contributing to air pollution and emissions. Moreover, enhancing the oxygen supply in the biological process to improve treatment efficiency is projected to escalate direct greenhouse gas (GHG) emissions. India's central electricity authority reports that the Indian grid produces around 0.91 kg CO2eq/kWh. A typical wastewater treatment plant (WWTP) demands an average of 185 kWh per million litres per day (MLD), resulting in approximately 168.35 kilograms of CO2 equivalent emissions per MLD [2]. Exploring alternative mitigation measures becomes imperative to address the energy demand from the grid. One approach involves employing mitigation technologies like gasification, anaerobic digestion, or pyrolysis to generate electricity from the sludge process. The study aims to estimate direct and indirect emissions from WWTPs by conducting a comprehensive life cycle assessment of various mitigation technologies. Notably, gasification, anaerobic digestion, and pyrolysis demonstrate potential emission reductions of around 81.8%, 57.2%, and 36.4%, respectively.

How to cite: Vidyarthi, P. K., Arora, P., Blond, N., and Ponche, J.-L.: Mitigation of GHG emission from the wastewater treatment plant: Life cycle assessment approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1146, https://doi.org/10.5194/egusphere-egu24-1146, 2024.

The Ulan Buh Desert, as one of China's eight significant deserts, is situated in the country's northwestern region and encompasses a diverse array of landscapes, including various desert types, vegetation, water bodies, and other landforms. This diversity is crucial for the ecological integrity and safety of the Yellow River Basin. The desert is notably constrained by water availability, and there has been a notable expansion in the degree of human activities, particularly regarding agricultural development, in the area.

Over the past 32 years, studies tracking the temporal and spatial variations of the Normalized Difference Vegetation Index (NDVI) in the Ulan Buh Desert have revealed a consistent increase in vegetative cover. Through the analysis of drivers such as climate change and human activity, it has been determined that temperature exhibits a positive correlation with NDVI, a relationship that has strengthened progressively over the years. Conversely, precipitation's influence on NDVI has been relatively insignificant. On the human activity front, contributions to NDVI changes have grown considerably, with such activities accounting for nearly a 50% increase in the vegetative index, suggesting that human interventions are increasingly aligning with ecological rehabilitation and positive environmental outcomes.

By scrutinizing the ecological consequences of both natural processes and human endeavors on the Ulan Buh Desert, insights gleaned can offer actionable recommendations for ecological restoration efforts, ensuring the sustainable management and recovery of this vital region.

How to cite: Yan, Y. and Cheng, Y.: Study of Changes in the Ulan Buh Desert under the Dual Impacts of Natural and Anthropogenic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1249, https://doi.org/10.5194/egusphere-egu24-1249, 2024.

EGU24-1717 | ECS | Orals | ERE1.6 | Highlight

Air quality improvements can strengthen China's food security 

Xiang Liu, Bowen Chu, Rong Tang, Yifan Liu, Xing Li, Jingfeng Xiao, Ankur Desai, and Haikun Wang

China, with nearly 20% of the world's population, achieves self-sufficiency in major grain production using only about 10% of the global arable land. To further ensure food security in China, it is crucial to gain a deep understanding of the driving factors behind grain production. Climate change, water scarcity, and air pollution pose serious threats to food production. Air quality in China is among the poorest in the world, thus quantifying its impact on grain production not only holds significance for maintaining its food security but also provides valuable insights into future air quality management policies. Here, we conducted a comprehensive analysis of the impact of aerosols and ozone on crop growth by integrating long-term, high spatial-temporal resolution remote sensing SIF data, crop planting information, and nationwide air pollution concentration data using nonlinear functional relationships and a two-way fixed-effects statistical model. The results show a consistent negative impact of ozone pollution on crop growth, while the effect of aerosols is varied by crop type and geographic location. By establishing a quantitative response relationship between crop growth and pollutant concentrations, we found that when China reaches the standard of 35 µg m-3 PM2.5, the average yields of corn, rice, and wheat nationwide will change by 0.45 ± 0.8%, 0.70 ± 0.22%, and −5.28 ± 2.97%, respectively. At the same time, reaching a warm-season ozone concentration of 60 µg m-3 in China will result in average national yield increases of 7.40 ± 1.32%, 3.40 ± 0.56%, and 8.71 ± 1.85% for corn, rice, and wheat, respectively. If China simultaneously meets both air pollution standards, the average daily per capita calorie intake of the three major crops will increase by 4.51%. Finally, our study suggests that, compared to reducing PM2.5, reducing ozone can more effectively increase domestic grain supply and further maintain China’s food security.

How to cite: Liu, X., Chu, B., Tang, R., Liu, Y., Li, X., Xiao, J., Desai, A., and Wang, H.: Air quality improvements can strengthen China's food security, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1717, https://doi.org/10.5194/egusphere-egu24-1717, 2024.

Diversifying cropping systems with grain legumes has been identified as a key measure to achieve the objectives set by European policies in terms of sustainability and protein self-sufficiency. Because grain legumes are sensitive to numerous biotic and abiotic stresses, expanding their production area in the context of climate change will require the implementation of adaptation strategies.

The objectives of this study are to shed light on what knowledge is needed by stakeholders to adapt grain legume cultivation to climate change and to assess matches and mismatches between these needs and crop-climate modelling. To this aim, we performed (i) a systematic literature review (n=83) to summarise recent simulation studies that assessed the impact of climate change and adaptation on grain legume performances in Europe, and (ii) interviews with 30 stakeholders involved in different stages of the value chain in France (cooperatives, seed breeders, extension services) to identify their needs.

Stakeholders’ information needs could be grouped into three categories: (i) information on profitability (including crop yield, pre-crop effect, and economic margin) and risks associated with growing grain legumes (including yield stability and risk of crop failure) and comparison of these variables with major crops like cereals, (ii) agroclimatic indicators such as rainfall distribution, heat waves, and frost days, that can be used to adjust crop management and identify climatic constraints to the introduction of new grain legume species (e.g., chickpea and soybean), and (iii) climate change impacts on diseases, pests, and their natural enemies. The appropriate time and spatial scales at which this information is relevant depend on the stakeholder. Stakeholders supporting farmers (e.g., extension services) expressed a need for short-term (up to 10 years) and local information, whereas cooperatives and stakeholders engaged in R&D were also interested in medium-term (up to 30 years) information at multiple spatial scales (from the cooperative’s supply area to the national and European scale).

When comparing these needs with our literature review, several mismatches were identified. Although stakeholders expressed a need for short to medium-term information, the reviewed studies focused mainly on the second half of the 21st century. The predominance of global-scale studies (63% of studies) contrasted with the need for local and regional data. We also highlight a lack of simulation studies assessing the impact of climate change on yield stability and economic indicators, especially relative to major crops like cereals. The impact of climate change on diseases, pests, and their natural enemies remains a blind spot, even though biotic pressure was identified as a growing concern for the stakeholders. Finally, although the majority of adaptation strategies identified by stakeholders (e.g., irrigation, changes in sowing date and density) have been studied in the literature, options such as substituting spring-sown crops with winter-sown crops and switching grain legume species have hardly been assessed (only one study).

Our results outline priority avenues for further research, considering the needs of stakeholders to support the development of grain legumes in Europe in the context of climate change.

How to cite: Marteau-Bazouni, M., Jeuffroy, M.-H., and Guilpart, N.: Assessing matches and mismatches between modelling and stakeholders’ needs to support the adaptation of grain legumes to climate change in Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1992, https://doi.org/10.5194/egusphere-egu24-1992, 2024.

Pathogens are a factor that determines emergency responses for both the public and the safety of first responders due to their life-threatening properties. At the same time, pathogen contamination is difficult to detect, and specialized skills, tools, and procedures are needed to deal with it. Waterborne pathogen contamination accidents can occur anywhere and for a variety of reasons. Earthquakes can cause disruptions to the urban drinking water and wastewater networks, and can also be contaminated by accidents, malicious attacks, and illegal activities.

This study developed a decision support system for pathogen contamination management in disaster situations by utilizing GIS technology. The system will not only enhance the operational capability of early responders (FRs) and strengthen overall management, but also reduce errors when setting up new technologies.

The system integrates various technical means, such as collecting and analyzing satellite and drone-based water quality data and evaluating the severity of water pollution using social media data. This enables rapid and accurate detection and re-response of environmental risks. The system is interconnected with various sources through REST and open APIs, and effectively manages data by utilizing MongoDB and geo-server.

The study is expected to make a significant contribution to protecting the environment and human safety by providing an accurate risk assessment and providing the necessary technical means to respond to pathogen pollution in disaster situations. Industrial accidents can be reduced by increasing the capacity to respond to risks that have not been specifically identified and strengthening the ability to respond to disasters. The study will also provide essential data for policy-making and regulatory development aimed at protecting the environment. 

This research was supported by Korea Institute for Advancement of Technology(KIAT) grant funded by the Korea Government(MOTIE)  (P163300014, 2021 Industrial Technology International Cooperation Project - Horizon2020 Program)

 
 

How to cite: Yoon, H., Son, S., Choi, I., Jo, J., and Kwon, J.: Designing a GIS-based Decision Support System to protect environmental and human health by integrating spatial data, environmental information, and health data for informed decision-making., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3774, https://doi.org/10.5194/egusphere-egu24-3774, 2024.

EGU24-6710 | Posters virtual | ERE1.6

Assessing adaptation strategies for potato cultivation in Morocco: modeling approaches at the field scale 

Assia Lozzi, Amandine Ouedraogo, Nassima Darrhal, Khalid Dhassi, and Saad Drissi

Climate change is set to reshape the environmental parameters governing crop growth, necessitating the implementation of revised management practices at the field scale. This study focuses on the adaptation and evaluation of the APSIM model for simulating the phenological growth, development, and yield prediction of potato (Solanum tuberosum L.) in response to climate variability in Morocco. Recognizing the critical role of potatoes in global food systems, and the increasing pressures of climate change, the research aims to accurately forecast the growth and yield responses of potato crops to these environmental shifts. The calibration phase of the APSIM model was rigorously conducted using local datasets, including climate patterns, soil properties, plant phenological data, and cropping practices. The model's accuracy was demonstrated through its high determination coefficients in simulating key growth stages and biomass accumulation of the potato crop. The findings showcase the model's capability in predicting potato yield and phenological responses to climate variability, providing strategic insights for enhancing agricultural practice efficiency. Overall, this study underlines the APSIM model's efficacy in developing strategies for climate-resilient potato farming, offering a robust tool for adapting agricultural practices under changing environmental conditions.

How to cite: Lozzi, A., Ouedraogo, A., Darrhal, N., Dhassi, K., and Drissi, S.: Assessing adaptation strategies for potato cultivation in Morocco: modeling approaches at the field scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6710, https://doi.org/10.5194/egusphere-egu24-6710, 2024.

EGU24-7063 | Orals | ERE1.6

Current Status of Pre-Calibration Techniques for Enhancing the Positional Accuracy of the Agricultural and Forestry Satellite 

Joongbin Lim, Chaeyeon Kim, Jong-Hwan Son, Taejung Kim, Sooahm RLee, Junghee Lee, Kyoungmin Kim, and Seunghyun Lee

The agricultural and forestry satellite, scheduled for launch in 2025, is a satellite being jointly developed by the Ministry of Science and ICT, the Rural Development Administration, and the Korea Forest Service of South Korea. Prior to its launch, technological developments have been made to ensure the positional accuracy of the agricultural and forestry satellite. For the geometric calibration of the satellite, a total of 4,650 precise image reference points have been established across the Korean Peninsula. These established precise image reference points have been verified to have a positional error of less than 1 meter based on field survey results. Utilizing this, the Rational Function Model (RFM) was corrected, determining the optimal parameters with six coefficients as suitable RFM correction coefficients for the precise geometric establishment of simulated images of the agricultural and forestry satellite. Subsequently, using the Digital Elevation Model for orthorectification, a final positional error of within 1 pixel (less than 5 meters) was confirmed.

How to cite: Lim, J., Kim, C., Son, J.-H., Kim, T., RLee, S., Lee, J., Kim, K., and Lee, S.: Current Status of Pre-Calibration Techniques for Enhancing the Positional Accuracy of the Agricultural and Forestry Satellite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7063, https://doi.org/10.5194/egusphere-egu24-7063, 2024.

EGU24-9018 | ECS | Orals | ERE1.6

Tabular Reinforcement learning for Robust, Explainable CropRotation Policies Matching Deep Reinforcement LearningPerformance 

Georg Goldenits, Kevin Mallinger, Thomas Neubauer, and Edgar Weippl

Abstract

Digital Twins are becoming an increasingly researched area in agriculture due to the pressure on food security caused by growing population numbers and climate change. They provide a necessary push towards more efficient and sustainable agricultural methods to secure and increase crop yields.
Digital Twins often use Machine Learning, and more recently, deep learning methods in their architecture to process data and predict future outcomes based on input data. However, concerns about the trustworthiness of the output from deep learning models persist due to the lack of clarity regarding the reasoning behind their outputs.

In our work, we have developed crop rotation policies using explainable tabular reinforcement learning techniques. We have compared these policies to those generated by a deep Q-learning approach, using both five-step and seven-step rotations. The aim of the rotations is to maximise crop yields while maintaining a healthy nitrogen level in the soil and adhering to established planting rules. Crop yields may vary due to external factors such as weather patterns, so perturbations were added to the reward signal to account for these influences. The deployed explainable tabular reinforcement learning methods perform similarly to the deep Q-learning approach in terms of collected reward when the rewards are not perturbed. However, in the perturbed reward setting, robust tabular reinforcement learning methods outperform the deep learning approach while maintaining interpretable policies. By consulting with farmers and crop rotation experts, we demonstrate that the derived policies are reasonable and that the use of interpretable reinforcement learning has increased confidence in the resulting policies, thereby increasing the likelihood that farmers will adopt the suggested policies.


Keywords: Digital Twin, Reinforcement Learning, Explainable AI, Agriculture, Crop Rotation Planning, Climate Change, Food Security

How to cite: Goldenits, G., Mallinger, K., Neubauer, T., and Weippl, E.: Tabular Reinforcement learning for Robust, Explainable CropRotation Policies Matching Deep Reinforcement LearningPerformance, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9018, https://doi.org/10.5194/egusphere-egu24-9018, 2024.

EGU24-10036 | ECS | Orals | ERE1.6 | Highlight

Effects of enhanced mineral weathering on soil structure and organic carbon storage 

Evelin Pihlap, Noemma Olagaray, Tobias Klöffel, Michael D. Masters, Ilsa B. Kantola, David J. Beerling, and Noah J. Planavsky

Enhanced mineral weathering is a nature-based solution to reduce atmospheric and soil CO2 concentrations in agricultural settings. Spreading finely grained basalt on the soil leads to subsequent chemical reactions that alters soil properties by changing soil pH, nutrient availability and particle-size distribution. Changes in these soil properties activate soil feedback mechanisms such as shifts in soil biogeochemical reactions or plant growth dynamics. Several studies have examined changes in pH and CEC after basalt application; however, basalt application may have an additional influence on the soil’s structural quality and the quantity of soil organic carbon (OC). In this study, we used a long-term field trial of basalt application at the University of Illinois Energy Farm (Illinois, USA) to elucidate changes in soil structure and OC storage. The field study was launched in 2016 using a randomized block design consisting of control (n=4, no basalt application), basalt (n=4), and lime (n=3) treatments. The sampling campaign was conducted in 2022 and in each field, we sampled with stainless steel cylinders (250 cm3) at depths of 1—6 cm and 15—20 cm. All samples were analyzed for nutrient content, OC concentration, pH, CEC and select samples were analyzed for soil water characteristic curves and aggregate-size distribution.

Basalt and lime application had a significant effect on soil pH, Ca concentration and the dominance of Ca2+ as an exchangeable cation, all which reflect evidence of increased soil structural quality. Indeed, soil structure, as quantified from the soil water characteristic curves using the concept of relative entropy (the Kullback-Leibler divergence), showed clear signs of enhancement after lime application. However, this was less evident for the basalt treatment. Despite improvements in soil structure, there were no effects on OC storage in either of the treatments. Aggregate characterization for OC concentration showed that the depth stratification had a greater role in carbon protection than the soil treatment itself, where the highest OC enrichment (EOC>1) was observed at the lower sampling depth of 15—20 cm. The organo-mineral association in the finest fraction was not affected by the treatment because neither the aggregate size class distribution nor OC accumulation in the finest fraction differed among the control, lime, and basalt treatments. Enhanced mineral weathering improves soil nutrient content, pH, and, potentially, soil structure; however, these changes do not directly result in higher OC storage, which underlines the complex nature of OC dynamics.

How to cite: Pihlap, E., Olagaray, N., Klöffel, T., Masters, M. D., Kantola, I. B., Beerling, D. J., and Planavsky, N. J.: Effects of enhanced mineral weathering on soil structure and organic carbon storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10036, https://doi.org/10.5194/egusphere-egu24-10036, 2024.

EGU24-13861 | Orals | ERE1.6 | Highlight

Assessment of Rice Yield Potential changes over Korean Peninsula under climate change with 1-km high resolution SSP-RCP scenarios  

Sera Jo, Yong-Seok Kim, Jina Hur, Kyo-moon Shim, Seung Gil Hong, Min-gu Kang, and Eung-sup Kim

The changes in rice climatic yield potential (CYP) across the Korean Peninsula are evaluated based on the new climate change scenario produced by the National Institute of Agricultural Sciences with 18 ensemble members at 1 km resolution under a Shared Socioeconomic Pathway (SSP) and Representative Concentration Pathways (RCP) emission scenarios. To overcome the data availability, we utilize solar radiation for CYP instead of sunshine duration which is relatively uncommon in the climate prediction field. The result show that maximum CYP(CYPmax) decreased, and the optimal heading date is progressively delayed under warmer temperature conditions compared to the current climate. This trend is particularly pronounced in the SSP5-85 scenario, indicating faster warming, except for the northeastern mountainous regions of North Korea. This shows the benefits of lower emission scenarios and pursuing more efforts to limit greenhouse gas emissions. On the other hand, the CYPmax shows a wide range of feasible futures, which shows inherent uncertainties in future climate projections and the risks when analyzing a single model or a small number of model results, highlighting the importance of the ensemble approach. 
This work was supported by a grant (no. RS-2021-RD009055) from the Rural Development Administration, Republic of Korea

How to cite: Jo, S., Kim, Y.-S., Hur, J., Shim, K., Hong, S. G., Kang, M., and Kim, E.: Assessment of Rice Yield Potential changes over Korean Peninsula under climate change with 1-km high resolution SSP-RCP scenarios , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13861, https://doi.org/10.5194/egusphere-egu24-13861, 2024.

EGU24-15122 | ECS | Posters on site | ERE1.6

Linking material cycles and ecosystem services assessment in forest modelling 

Cholho Song, Chul-Hee Lim, Youngjin Ko, Jiwon Son, Hyun-Ah Choi, and Woo-Kyun Lee

In ecosystem services assessment in South Korea, many studies have applied various modelling methods. However, these modelling approaches mainly focused on the statistical growth model based on the national forest inventory, so calculating carbon was the main target of research. Statistical modelling enables annual assessment of the carbon budget in forests, but it was limited to understanding daily ecosystem changes and other material cycles. Therefore, this study tried to set up the linkage of material cycles and ecosystem services using various current modelling schemes in South Korea. Therefore, the process-based model and current forest models were applied to assess carbon and ecosystem productivity. In addition, their possible linkage to ecosystem services was analyzed. From the process-based model, the net primary productivity value was calculated at around 5.17 Mg C ha-1 average, and it indicated around 1.61 Mg C ha-1 in net carbon sequestration during the 2021-2100. Considering the current projection of annual carbon sequestration, this value is similar to the current model projection. In addition, the process-based model calculated evapotranspiration, respirations, and other values which converted ecosystem services, especially climate regulation, supporting ecosystem services, and provisioning ecological materials. Linkage of these models can support to assessment of many other non-assessed ecosystem services, and an ensemble of modelling and expanded modelling in ecosystem services will be required to assess Korean ecosystem services.

How to cite: Song, C., Lim, C.-H., Ko, Y., Son, J., Choi, H.-A., and Lee, W.-K.: Linking material cycles and ecosystem services assessment in forest modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15122, https://doi.org/10.5194/egusphere-egu24-15122, 2024.

Invasive pest species are the most serious threat to the resilience of agroecosystems. They cause direct damage by reducing crop yield and increasing management costs, and indirect damage through agroecosystem disturbances. To mitigate the risks posed by invasive pests, identifying their potential distribution is a crucial prerequisite. This study predicted the climatic suitability of the rice stem borer (RSB), Chilo suppressalis, within Europe using a species distribution model, CLIMEX. RSB first invaded Spain in the 1930s and has since caused significant damage, with reports of its presence in France, Hungary, and near the Caspian Sea in Russia. The overall suitability for RSB in Europe, while lower than its native region in East Asia, is predicted to be habitable across the European mainland. Notably, the climates of Mediterranean countries (e.g., Greece, Italy, France, Spain, Croatia, etc.) are expected to be sufficiently suitable for RSB habitation. Currently, RSB is also reported in Hungary, but the exact route of invasion is unclear; thus, it is necessary to investigate whether these are extensions of the existing populations in Spain and France or the result of accidental introduction through trade. Moreover, in southern Europe, where rice production is high, there is a risk of significant damage similar to that in Spain. Therefore, quarantine and prevention measures against RSB invasion are required.

How to cite: Hong, J. and Cho, K.: Potential Invasion risk of the rice stem borer, Chilo suppressalis, in Europe using CLIMEX., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15677, https://doi.org/10.5194/egusphere-egu24-15677, 2024.

The risk of wildfires is increasing due to rising temperatures and worsening dry conditions resulting from climate change (Westerling et al., 2008; Vilà-Vilardell et al., 2020). Human activities, driven by urbanization and population growth, contribute to the occurrence of wildfires. As wildfires are a consequence of the complex interplay of various factors, an integrated understanding of the social and ecological systems influencing wildfires is crucial for protecting human communities and preserving the natural environment. Particularly, the Wildland-Urban Interface (WUI), an area where urban and natural landscapes and vegetation coexist or are adjacent, represents a space where the interaction between human activities and natural systems is pronounced (Stewart et al., 2007). A specific and clear analysis and management of the WUI’s social-ecological system is necessary due to the severe damage caused by urban wildfires.

There is a growing awareness of the necessity to establish effective prevention and management strategies to protect urban systems. However, there is a lack of research on social-ecological systems over time, such as before and after wildfires in the WUI. Therefore, the objective of this study is to conduct a comprehensive analysis of the socio-ecological system of urban WUI areas, with a focus on identifying and evaluating the factors influencing the resilience of these systems. By examining the interactions within the WUI’s socio-ecological framework, the research aims to propose strategies for enhancing the capacity of urban areas to adapt to and recover from environmental disturbances, thereby contributing to the development of robust and resilient urban social-ecological systems.

To define and categorize socio-ecological systems, a spatial analysis of wildfire-prone areas was employed and to identify and evaluate the factors affecting the resilience of the system in response to wildfires, system analysis tools and models were utilized.

Building upon this study, future research will employ the Urban Resilience Index classification to derive strategies for each type of green infrastructure planning based on the 4Rs of resilience (robustness, rapidity, redundancy, and resourcefulness) to improve urban socio-ecological resilience for wildfire response in urban Wildland-Urban Interface (WUI). The results can be utilized to develop a green infrastructure planning decision support system.

References

Westerling, A. L., & Bryant, B. P. (2008). Climate change and wildfire in California. Climatic Change, 87(Suppl 1), 231-249.

Stewart, S. I., Radeloff, V. C., Hammer, R. B., & Hawbaker, T. J. (2007). Defining the Wildland-Urban Interface. Journal of Forestry, 105(4), 201-207.

Sullivan, A., Baker, E., & Kurvits, T. (2022). Spreading like wildfire: The rising threat of extraordinary landscape fires.

※ This work was supported by the Core Research Institute Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A10045235).

How to cite: Kang, S. and Lee, J.: Analysis of Influencing Factors to Enhance Resilience of Urban Social-Ecological Systems in Urban Wildfire Response, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16379, https://doi.org/10.5194/egusphere-egu24-16379, 2024.

EGU24-16948 | Orals | ERE1.6

Are There Carbon-Neutral Cities in South Korea: Using Residual Modeling on Different Spatial Scales 

Yujeong Jeong, Sujong Lee, Mina Hong, Youngjin Ko, Hyun-Woo Jo, and Woo-Kyun Lee

To achieve the national carbon neutrality goal by 2050, it is crucial to be spatially strategic. Understanding the spatial distribution of carbon balance in different levels of spatial scales from global/continental scales to urban, and province/state is essential. This paper aims to estimate the spatial distribution of carbon balance in South Korea using an integrated carbon balance estimation model and to identify the disparity of carbon-emission characteristics determined by three different spatial divisions ¾ metropolitan and basic local governments, and town-level (eup/myeon/dong&li). Two-step ridge regression model using residuals was established based on land cover maps, population maps, and energy production data to analyse the distribution of carbon emissions. The distribution of carbon sequestration was calculated using the Korean forest growth model (KO-G-Dynamic model). The results from each model were calibrated and validated by the National Greenhouse Gas Inventory of basic local governments. The carbon balance was quantified by integrating the results of carbon emission and carbon sequestration. Surprisingly, the results showed that several cities, especially along the biggest mountain range in South Korea, have already achieved regional carbon neutrality. This is particularly true when the spatial scale is below a metropolitan government level. Additionally, the study found that the narrower the spatial scale of distribution becomes, the greater the number of urban/provinces with a carbon balance under zero. Obviously, carbon-neutral regions are characterized by low energy and industrial facilities and high forest density and, in most of the top emitting regions, vice versa. This study provides insights into the methodology for researching the spatial distribution of carbon balance. It also highlights the need for constructing carbon reduction pathways and strategies that reflect the regionality of carbon balance in multi-level districts. With further development of the study, the result could be used as scientific evidence for the effective fulfillment of regional carbon neutrality.

How to cite: Jeong, Y., Lee, S., Hong, M., Ko, Y., Jo, H.-W., and Lee, W.-K.: Are There Carbon-Neutral Cities in South Korea: Using Residual Modeling on Different Spatial Scales, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16948, https://doi.org/10.5194/egusphere-egu24-16948, 2024.

EGU24-17914 | Posters virtual | ERE1.6

Impact of climate change on coffee agrosystems and potential of adaptation measures 

Raniero Della Peruta, Valentina Mereu, Donatella Spano, Serena Marras, and Antonio Trabucco

Coffee is one of the most economically important agri-food systems globally, and is the main source of income for many rural households in several developing countries. Ongoing climate change could cause problems for sustainable coffee production, with greater instability from year to year and lower average yields. To overcome these problems, possible adaptation measures and agronomic practices should be evaluated, such as intercropping with other tree species that can provide more shade for coffee plants and promote resilience and environmental sustainability. To study the effectiveness of such options, the use of process-based models can be very useful.

The DynACof model was developed specifically to simulate coffee agrosystems, including phenological development, physiological processes related to flower and fruit production, carbon allocation, the effect of water availability, light and temperature, and management. We validated the yields modeled by DynACof with productivity data available from some sites and areas included in previous evaluation studies in Mexico, Rwanda, Brazil, Ethiopia, and Costa Rica. We then developed and established a modeling framework in which the model can be applied spatially on a continental or pan-tropical scale, using extended climate projection ensemble and soil geodata.

Our modelling tool was then used to simulate potential yields in Latin America and Africa for both 1985-2014 and 2036-2065, using an ensemble of statistically downscaled and bias adjusted climate projections for two different shared socioeconomic pathways. Comparing the two periods, the model predicts a decrease in yields between 23 and 35 percent in Latin America and between 16 and 21 percent in Africa. The spatial representation of these changes indicates a likely future shift of suitable production areas to higher elevations, possibly impacting fragile mountain ecosystems. We simulated a specific management option, namely increased agroforestry shading, to evaluate its effectiveness in improving resilience to climate risks. The results suggest that increased tree shading could partially reverse the trend of declining yields due to climate change in some lowland areas. However, these preliminary results must be confirmed by further analyses. Impact analysis and adaptation modeling of coffee agrosystems, together with socioeconomic indicators, have the potential to delineate realistic integrated risk assessments and support effective adaptation recommendations.

How to cite: Della Peruta, R., Mereu, V., Spano, D., Marras, S., and Trabucco, A.: Impact of climate change on coffee agrosystems and potential of adaptation measures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17914, https://doi.org/10.5194/egusphere-egu24-17914, 2024.

EGU24-18453 | Orals | ERE1.6

Analysis of South Korea's 3S Forest Management Pathways for Carbon Neutrality Achievement 

Mina Hong, Jinwon Son, Moonil Kim, YoungJin Ko, and Woo-Kyun Lee

In recent years, global climate change has emerged as a critical issue, exerting widespread impacts across various sectors. In response, the Intergovernmental Panel on Climate Change (IPCC) has emphasized the urgency of preparing for a 2℃ temperature rise by focusing on greenhouse gas reduction strategies and the vital role of forests as carbon sinks. Aligning with international efforts, South Korea has formulated the "2050 Carbon Neutrality Strategy" and presented corresponding strategies in the forestry sector. This research utilizes the Korean Dynamic Forest Growth Model to explore forest management pathways aimed at achieving carbon neutrality through the aspects of sequestration, storage, and substitution (3S). The study incorporates climate change scenarios and forest policies to select appropriate management pathways. The assessment of various scenarios revealed that the combination of the SSP1 climate change scenario, clear-cutting, thinning of approximately 200,000 hectares, reforestation with suitable species, and ensuring a maximum forest road accessibility of 1 km produced significant and meaningful results across all three aspects of forest management (sequestration, storage, and substitution). As a result, sequestration of 28.49 million tCO2 yr-1, a storage of 2.1 billion tCO2 yr-1, and the substitution 7.92 million m3 of harvested wood products (HWP) in the 2050. Furthermore, the 3S forest management approach is expected to contribute to mitigating tree-age imbalances and provide resilience against the impacts of climate change. In conclusion, this study is meaningful in that it suggested a spatio-temporal forest management path by reflecting the environmental characteristics of Korea for achieving carbon neutrality. This is considered to be able to contribute to local government carbon neutrality achievement plans and national policies.

 

How to cite: Hong, M., Son, J., Kim, M., Ko, Y., and Lee, W.-K.: Analysis of South Korea's 3S Forest Management Pathways for Carbon Neutrality Achievement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18453, https://doi.org/10.5194/egusphere-egu24-18453, 2024.

EGU24-18916 | ECS | Orals | ERE1.6

Systematic Analysis of the Impact of Mangrove Forest Changes on Ecosystem Services in Vietnam 

Mikyeong Tae, Min Kim, and Jinhyung Chon

Mangroves, a form of blue carbon, encompass approximately 1,054,900 hectares globally, with Vietnam possessing 75,900 hectares, representing around 7% of the total area. Beyond providing essential resources such as food, timber, and habitat, mangroves confer diverse ecosystem services, including coastal erosion mitigation and carbon sequestration while attenuating wave energy. Nevertheless, the pervasive impacts of climate change and anthropogenic activities are precipitating a reduction in mangrove coverage, giving rise to socio-ecological challenges, including biodiversity loss, escalated carbon emissions, and heightened vulnerability to severe flooding. Efforts are underway to address this predicament; however, accurate assessment remains challenging due to the intricate nature of mangrove habitats. Survey-derived data suffers from accuracy limitations, necessitating comprehensive research utilizing satellite imagery for efficient identification within a condensed timeframe, employing a systems thinking approach to understand complex ecosystem services holistically.

This research aims to detect changes in the area of mangrove forests in Vietnam using Landsat satellite imagery from 2010 to 2020, the initial implementation period of the Vietnam Forestry Development Strategy, and to analyze the impact of these changes on ecosystem services.

To achieve this, high-resolution (30cm) satellite images are utilized to calculate specific vegetation indices such as NDVI, NDWI, and SAVI in QGIS software.

 These indices are instrumental in detecting alterations in mangrove coverage throughout Vietnam. Additionally, this study employs systems thinking to construct a causal chain map that illustrates how changes in the mangrove area impact ecosystem services within Vietnam.

Satellite imagery was harnessed for GIS analysis to evaluate the ongoing status of Vietnam's mangrove forest area over time. The alterations in the area were quantified by grid partitioning, and causal loop diagrams were utilized to comprehend how modifications in mangrove areas affect ecosystem services such as coastal protection, water purification, habitat provision, and food supply. These changes engender trade-offs.

This study is significant as it utilizes high-resolution satellite data to quantify the change in Vietnam's mangrove forest area over time. It also underscores the impact of these changes on ecosystem services from a systems-thinking perspective. Moreover, deducing the ecosystem service structure of mangrove forests from causal chain maps can serve as a cornerstone for formulating policies aimed at safeguarding mangrove forests for decision-makers in Vietnam and other countries with similar ecosystems. Additionally, exploring the potential of mangroves as blue carbon sources can contribute significantly to carbon neutrality and planning.

Acknowldegemt

This research was supported by "Development of living shoreline technology based on blue carbon science toward climate change adaptation" of Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (KIMST-20220526)

How to cite: Tae, M., Kim, M., and Chon, J.: Systematic Analysis of the Impact of Mangrove Forest Changes on Ecosystem Services in Vietnam, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18916, https://doi.org/10.5194/egusphere-egu24-18916, 2024.

Renewable energies, particularly solar and wind power, are gaining prominence in the shift towards a carbon-neutral climate. however, challenges for wind power include ecological disruption, coastal landscape degradation, and visual impact due to offshore turbine installation. Technological limitations currently dictate offshore wind turbines' placement 10 to 30 kilometers inland, raising concerns about light environmental changes affecting nearby coastal areas. This raises concerns about the potential impact of light environmental changes such as the effects of aviation obstruction lights on wind turbines and blade movements on inland areas close to the coastline.  Therefore, developing offshore wind farm plans analyzing the impact of light environment changes and proposing mitigation measures is crucial.
In this study, we analyze the light environmental impact of wind power and propose mitigation measures to minimize its effects on the planned offshore wind farms in the South Sea's Aphae area, surrounded on three sides by sea and offering favorable conditions for marine renewable energy development, and the West Sea's Jangbogo area in South Korea.
The assessment utilized 2022 Day and Night Band (DNB) satellite imagery from the VIIRS sensor to evaluate light pollution. QGIS was subsequently employed to analyze visible frequency, turbine shadow impact range, and distance from the power generation site, resulting in a light environment value assessment map. Key points were identified on the map, and the study further examined the influence of turbine blade movements on aviation obstruction lights and shadow flickering using QGIS and WINDPRO.
As a result of measurements using VIIRS satellite images, the light pollution levels at the Aphae and Jangbogo sites were found to be approximately 0.631542 × 10-9 W/cm²sr and 0.38 × 10-9 W/cm²sr, respectively. In Aphae, the impact of light pollution was generally minimal, less than 0.002 cd/m², but it did have an impact in the northern coastal area. Jang Bogo measured less than 0.002 cd/m², indicating a low impact on island residents.
As a result of light pollution analysis, it was found that shadow flickering occurs for 30 to 60 minutes a day for more than 120 days a year in the northern coastal area of Aphae. Jangbogo showed very limited shadow flickering, less than 10 hours per year and less than 10 minutes per day in certain areas. The impact of light pollution is expected to be minimal in Jang Bogo, and mitigation measures are needed to alleviate pressure damage. Recommendations may include adjustments to the layout of offshore wind farms or changes to the coordination of offshore wind operations.
This study is significant in analyzing the impact of light environmental changes caused by offshore wind power on inland areas and proposing mitigation measures. Furthermore, the findings of this research can be applicable to environmental studies for the development of offshore wind farms in other regions in the future.

Acknowledgement

This research was supported by “Development of Advanced Science and Technology for Marine Environmental Impact Assessment” of Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (20210427)

How to cite: Choi, H., Kim, M., and Chon, J.: Assessing Light Environmental Impact in Offshore Wind Farm: A Case Study of Aphae and Jangbogo Areas in South Korea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19001, https://doi.org/10.5194/egusphere-egu24-19001, 2024.

Climate change is altering weather patterns around the world, and one notable effect is changes in the jet stream that controls weather systems. As the polar regions warm faster than lower latitudes, the temperature difference that drives the jet stream winds decreases, causing them to become more frequent and the air masses to stagnate. This could lead to prolonged periods of extreme weather, including deadly heat waves, floods and droughts. An example of this can be seen in 2018, when a heat wave broke record high temperatures in Korea due to blocking (a phenomenon in which air flow stagnates in the upper mid-latitudes, weakening westerly winds and causing strong north-south winds) by Rossby waves. Life-threatening heat persists without an increase in low-pressure systems that bring cooling rain.

This study uses a systems ecology approach to examine the interactions between energy and material cycles in interconnected ecosystems in East Asia. The region's rapid urbanization, industrial growth, and high population density have significantly altered heat and material flows and cycles. These anthropogenic changes, together with natural climate variability, have complex and far-reaching impacts on regional climate patterns and ecosystem health.

East Asia's built environment and demographics have fundamentally disrupted natural stability mechanisms. Rapid development has replaced heat-reflecting green spaces with heat-absorbing concrete structures, reducing evaporative cooling capacity. Sprawling road systems filled with vehicle heat exacerbate urban heat islands.

In addition, climate-induced changes in the natural cycles of water, carbon, and nutrients link ecosystems in complex ways. Quantifying changes in cycling by evaluating historical data and models provides a basis for predicting ecosystem stability and resilience in the face of climate change. For example, a decrease in relative humidity in an area increases the risk of wildfires as moisture is removed from dead grass, fallen trees, and leaves. In areas with low relative humidity and abundant fuel-rich vegetation, the risk of wildfires may increase, particularly in winter and spring. A systematic understanding of these dynamics is essential to guide regional climate change adaptation planning.

Finally, the study translates its findings into policy recommendations. By analyzing the positive impacts of increased plant cover on humidity and overall ecosystem water availability, this study provides actionable steps towards a more resilient East Asia.

Acknowledgements: This research was supported by the Core Research Institute Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A10045235).

How to cite: Park, H., Song, C., and Lee, W.-K.: Impacts of Climate Change on the Energetics and Ecosystem Material Cycles and Extreme Weather Events: An East Asian Case study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19195, https://doi.org/10.5194/egusphere-egu24-19195, 2024.

EGU24-19777 * | Posters on site | ERE1.6 | Highlight

Multi-purpose afforestation scenarios under climate change for carbon dioxide reduction  

Florian Kraxner, Dmitry Schepaschenko, Sabine Fuss, Andrey Krasovskiy, Anatoly Shvidenko, Georg Kindermann, Hyun-Woo Jo, and Woo-Kyun Lee

This study aims at identifying the carbon dioxide reduction (CDR) potential of large-scale and multi-purpose afforestation/reforestation at the global level with special emphasis on the Mid-Latitude Region (MLR). Applying a combined remote sensing/GIS approach coupled with biophysical forest and disturbance modeling under various climate change scenarios, we identify potential afforestation locations, inter-alia on abandoned agricultural land and on areas burnt from wild land fires. With the help of IIASA’s biophysical global forestry model (G4M), we calculate the associated land-based CDR potentials through carbon sequestration in afforested biomass and through climate risk-resilient and sustainable forest management dedicated to the supply of bioenergy plants coupled with carbon capture and storage (BECCS) facilities. Finally, three promising scenarios have been identified including I) afforestation; II) reforestation; and III) BECCS. In all scenarios, priority is put on sustainable forest management and nature/biodiversity conservation. Forest modeling results have been combined with recent data sets which have been overlayed in order to provide a unique basis to estimate the land-based CDR technologies’ potential to mitigate climate change and contribute to reaching the goals of the Paris Agreement. In the case of afforestation, preliminary results indicate a total potential afforestation area greater than 1 billion ha.  The largest area potential for afforestation have been identified in the USA. Given the higher productivity (combined with large area available), Brazil is the country with the highest total CDR potential of close to 500 MtC/yr.

How to cite: Kraxner, F., Schepaschenko, D., Fuss, S., Krasovskiy, A., Shvidenko, A., Kindermann, G., Jo, H.-W., and Lee, W.-K.: Multi-purpose afforestation scenarios under climate change for carbon dioxide reduction , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19777, https://doi.org/10.5194/egusphere-egu24-19777, 2024.

EGU24-20157 | Orals | ERE1.6

A Green Infrastructure Approach through Carbon Cycle Analysis and Decision Support 

Jiangong Bi, Sangchul Lee, and Junga Lee

Due to climate change, abnormal weather conditions such as floods, droughts, heavy snow, and heatwaves are escalating globally. Recent climate observations and model predictions indicate a trend toward more frequent and intense extreme climate events in the near future, attributed to anthropogenic greenhouse gas emissions. When floods occur, they simplify the habitats of ecosystems, leading to a reduction in diversity and water quality pollution. Basin ecosystems play a crucial role in carbon absorption, mitigation, and providing habitats for plants and animals. Therefore, it is imperative that plants, soil, and wetlands within the watershed ecosystem absorb and sequester carbon from the atmosphere to decrease greenhouse gas concentrations. Consequently, there is a necessity for research on decision support tools capable of identifying and analyzing the factors influencing carbon circulation during a flood.

 

The primary objective of this study is to develop a decision support tool for green infrastructure (GI) planning in watershed ecosystems to enhance resilience against climate change. The tool will help identify and analyze factors affecting the carbon cycle during flood events and enable the creation of GIs that support the carbon cycle.

 

The expected results from the study combine positive factors that can lead to various positive and combining factors, so future research can create scenarios through combinations of factors. The scenarios created can result in GIs that can perform ad hoc tasks by choosing more efficient configurations.

 

 

References

Michael W. Strohbach, Eric Arnold, Dagmar Haase. The carbon footprint of urban green space—A life cycle approach. Landscape and Urban Planning, Volume 105, Issue 4, 30 April 2012, Pages 445

 

※ This work was supported by the Core Research Institute Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2021R1A6A1A10045235).

※ This work was supported by Korea Environment Industry &Technology Institute (KEITI) through "Climate Change R&D Project for New Climate Regime.", funded by Korea Ministry of Environment (MOE) (2022003570003)

How to cite: Bi, J., Lee, S., and Lee, J.: A Green Infrastructure Approach through Carbon Cycle Analysis and Decision Support, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20157, https://doi.org/10.5194/egusphere-egu24-20157, 2024.

Abstract

The expansion of impervious surfaces resulting from urbanization induces alterations in the natural water cycle system, culminating in urban flooding. Persistent flood damage arises from issues such as the failure to designate flood-prone areas despite receiving flood reports or the exclusion from flood-prone zones due to complaints. Both the central government and local authorities are taking measures to designate and manage flood-prone areas, recognizing the necessity to address this issue not only from an ecological standpoint but also considering social aspects, including the real estate value of the region and the effort and cost of flood damage recovery. Furthermore, flood resilience should be a central consideration, aiming to identify existing problems through the virtuous cycle process of flood damage, both upstream and downstream, and working towards recovery or improvement to a state superior to pre-flood conditions.

This study's objective is to redefine the criteria for green infrastructure planning in flood-prone zones, exploring interrelated factors influencing urban water systems and identifying synergistic solutions to enhance resilience. The application of systems thinking involves four integral stages: dynamic thinking, causal thinking, closed-loop thinking, and strategic discovery. These stages collectively establish a systematic dynamic loop. To construct this loop within the complexity of a water circulation system, initial attention must be given to discharge management. Ensuring a robust water cycle necessitates the equitable distribution of runoff across processes such as evaporation, filtration, infiltration, and groundwater recharge. Secondly, green infrastructure design should leverage technologies that harness natural mechanisms, enhancing the cyclical movement of materials within the ecosystem. This involves strategic infrastructure planning that minimizes alterations to topography, preserving the natural functions of the water cycle while allowing for flexible application tailored to ecosystem requirements. These green infrastructure characteristics, effects, and plans are summarized as variables. Thirdly, the dynamic loop is constructed with consideration of the summarized variables. The final stage of the process integrates flood risk management within a community flood resilience framework. By cycling through the stages of learning, prevention, resistance, response, and recovery, the objective is to minimize damage caused by floods and effectively respond to unexpected floods due to climate change.

As a result, seven derived criteria include land use type identification, target site characteristics analysis, detailed survey, water circulation goal selection, design criteria and layout strategy, spatial suitability evaluation, and water cycle change verification. Using these criteria, the ultimate goal of this study is to identify suitable green infrastructure locations and create a monitoring map for a healthy water cycle. The study aims to contribute to flood prevention measures in flood-prone areas by analyzing the impact of green infrastructure on emissions.

Acknowledgements

This work was supported by Korea Environment Industry &Technology Institute (KEITI) through "Climate Change R&D Project for New Climate Regime.", funded by Korea Ministry of Environment (MOE) (2022003570003).

References

EPA, U. (2007). Reducing stormwater costs through low impact development (LID) strategies and practices. United States Environmental Protection Agency, Nonpoint Source Control Branch (4503T).

How to cite: Lee, W. J., Jeon, S., and Lee, J.: Green infrastructure planning criteria for flood-prone areas to restore water cycle system and improve flood resilience , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20208, https://doi.org/10.5194/egusphere-egu24-20208, 2024.

EGU24-22025 | Orals | ERE1.6 | Highlight

Towards a better integration of the human and biophysical dimensions in global change modelling 

Christian Folberth, Peter Burek, Taher Kahil, Florian Kraxner, Michael Kuhn, Amanda Palazzo, Stefan Wrzaczek, and Dilek Yildiz

Global change encompasses on the environmental side components such as climate change, land degradation and pollution; and in the societal domain socioeconomic changes such as demography, economic development, and equality. This nexus is primarily driven by human activities and affects outcomes relevant for peoples’ well-being and viability through a network of interactions and feedbacks. Due to its strong influence on land surface and land-atmosphere processes and as a basis for food security and income, agriculture and rural livelihoods are at the heart of global change.

Despite the close entanglement of rural populations, livelihoods, and agricultural production, their integrated assessment is so far hardly considered in large-scale and global foresight studies. Instead, most large-scale research on consequences of global change and potential solutions is still monothematic or combines few of the above elements.

Integration across disciplines is taking place only to a limited extent, typically with static combinations of model outcomes. E.g., integrated land use models typically combine yield projections for changing climate with a priori projections of economic and population change. Other examples are the combination of independent projections of crop productivity and water availability to analyze adaptation potentials within the biophysical domain or across scientific domains the estimation of migration driven by changes in crop productivity and water availability. Importantly, both mono- and interdisciplinary studies are most often confined to business-as-usual scenarios or trajectories along shared socioeconomic pathways. Consequently, they do not capture feedbacks involving the human dimension and potentials for adaptation, and therefore lack outcomes that can inform on options for local and regional decision-making covering the water-food-population nexus.

The state-of-the-art highlights a concerning lack of integrated approaches to model global change impacts and feedbacks across environmental and socioeconomic domains. Based on own research and literature that characterizes interactions in the water-food-population nexus under global change pressures and existing model types and approaches, we propose herein a platform for the quantitative integrated modelling and assessment of global change impacts and adaptation covering food and water security, land use, demography, migration, and adaptive capacity.

Applications of such a modelling platform may address a wide range of pressing questions including shocks, their cascading effects and ultimate feedbacks (e.g. food security through output and input trade during and after Ukraine war; other historic shocks such as financial crisis; etc.); slow-onset global change impacts and adaptation; or transversal achievement of SDGs; and eventually serve as a first step towards the modelling of societal catastrophic change scenarios.

How to cite: Folberth, C., Burek, P., Kahil, T., Kraxner, F., Kuhn, M., Palazzo, A., Wrzaczek, S., and Yildiz, D.: Towards a better integration of the human and biophysical dimensions in global change modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22025, https://doi.org/10.5194/egusphere-egu24-22025, 2024.

Carbon capture and storage technology is a necessary means to achieve the temperature control goal of 1.5 degrees Celsius under the background of peak carbon dioxide emissions and carbon neutrality. The storage of carbon dioxide in oil and gas reservoirs has the advantages of high safety, large storage capacity, and less additional cost. The reservoir-caprock configuration can provide favorable space for the storage of carbon dioxide geological bodies. To make clear the distribution range of geological bodies suitable for carbon dioxide sequestration, taking the middle-south section of the eastern sag of Liaohe as an example, based on the model of the ratio of mud to ground and caprock effectiveness division, the control factors of caprock sealing were analyzed by entropy weight method combined with TOPSIS method, and the effective thickness of reservoir was determined by clarifying the relationship between reservoir lithology, physical properties, oil content and electricity. The results show that the lower limit of the effective caprock mud-to-ground ratio in the sand-mud interbedding sequence is 70.6%, and the sealing ability of caprock is mainly affected by the thickness of the fault and the thickness of the caprock single layer; The two sets of caprocks in the Shahejie Formation and Dongying Formation are relatively stable, with good fault-caprock configuration sealing, and the fault juxtaposition thickness in the Shahejie Formation is characterized by "thick in the north and thin in the south"; The effective reservoirs of the Dongying Formation are distributed in the whole region, the effective reservoirs of Es1 are distributed in the north of Rongxingtun, and the distribution range is smaller than that of the Dongying Formation, while the effective reservoirs of Es3 are mainly distributed in Huangyure area at the northern end of the study area, and the distribution range is further reduced. According to the reservoir-caprock configuration, carbon dioxide storage types can be divided into three types: shallow storage type, deep storage type, and multi-layer storage type. The lower caprock is well sealed and the lower effective thick reservoir controls the deep enrichment of carbon dioxide; The lower caprock is poorly sealed, and the effective thick reservoir in the middle or upper part controls the multi-layer enrichment of carbon dioxide; The lower caprock is poorly sealed, the upper caprock is well sealed, and the upper effective thick reservoir controls the shallow enrichment of carbon dioxide. The relationship between the effective thickness of the reservoir and the sealing ability of the caprock determines the vertical distribution series of carbon dioxide.

How to cite: li, H. and jiang, Y.: Study on Reservoir-caprock Configuration for Carbon Dioxide Sequestration in oil and gas reservoirs , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-86, https://doi.org/10.5194/egusphere-egu24-86, 2024.

EGU24-362 | ECS | Posters on site | ERE1.8

Towards net-zero: assessing the carbon storage potential of onshore saline aquifers in Brazil 

Francyne B. Amarante, Juliano Kuchle, and Mauricio B. Haag

Global warming poses a major challenge that humanity will face during the 21st century, requiring a significant reduction in anthropogenic CO2 emissions to mitigate the escalating global temperature. Several governments worldwide, including Brazil, have committed to achieving net-zero CO2 emissions by 2050, which will be impossible without Carbon Capture, Utilisation and Storage (CCUS) deployment. Ranked 12th globally in CO2 emissions (and 1st in South America), Brazil is in the early stages of studying CCUS. At present, CCUS efforts in the country primarily revolve around enhanced oil recovery, with limited exploration of CO2 injection in alternative geological settings. A total of 31 sedimentary basins span Brazilian territory, encompassing an area of approximately 6.4 million km2, 75% of which is situated onshore. The potential for CO2 storage in saline aquifers is gaining attention globally, proving a successful and effective approach in various sites. In this work we combine the available surface (geological maps, roads, and gas pipelines) and subsurface data (seismic lines and borehole data) to assess the logistics and feasibility of utilizing saline formations in onshore intracratonic basins as CO2 sinks, aiming to enable Brazil to reach net-zero CO2 emissions by 2050. Previous studies indicate that the Parnaíba, São Francisco, Amazonas, and Paraná basins present saline formations with favorable characteristics for CO2 injection, such as adequate depths, porosity, and permeability. Building upon prior research, we introduce the onshore portion of Espírito Santo Basin to the list of potential sinks, where the target saline aquifer is the pre-salt Mucuri Formation. Results show that greenhouse gases emissions from industrial processes are notably higher in the southeast region of Brazil. Within this region, two formations exhibit considerable potential for carbon sequestration in saline aquifers: (i) the Mucuri Formation, located in the onshore Espírito Santo Basin, reaching 350 m of thickness and shallowest depths of about 950 m, and (ii) the Rio Bonito Formation, in the proximities of the São Paulo state, with over 100 m of thickness and shallowest depths of about 650 m. For large-scale projects, CO2 transport in the region can be accomplished using the available infrastructure and the available gas pipelines, while smaller-scale research projects can utilize trucks, rail, and ships. Brazil's untapped potential for CCUS presents a unique funding opportunity from the private sector, marking a crucial step toward sustainable and impactful climate action.

How to cite: B. Amarante, F., Kuchle, J., and B. Haag, M.: Towards net-zero: assessing the carbon storage potential of onshore saline aquifers in Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-362, https://doi.org/10.5194/egusphere-egu24-362, 2024.

EGU24-800 | ECS | Posters on site | ERE1.8

Ultrasonic Evaluation of Shales vis-à-vis Temperature: A Case Study from Permian Damodar Valley Basin 

Varun Dev Jamwal and Ravi Sharma

Despite constituting two-thirds of the sedimentary rock volume, shales are a few of the least understood rocks. The varied depositional processes and environments give rise to complexity and anisotropy in them. Understanding unconventional resources like shales becomes crucial given their abundance in the petroleum systems and reservoirs and their potential suitability for sub-surface carbon and radioactive waste storage. Therefore, paramount significance lies in understanding the petrophysical and rock physical characteristics of shales to develop feasibility models for the sustainable use of these rock types.
 
This investigation focuses on the Barren Measures and Raniganj Formation shales in the Damodar Valley of Eastern India, which are primarily rich in clays, carbon, and iron and are of fluvio-lacustrine origin. These relatively shallow formations can be good sites for storage and sequestration as they are overlain by shaley and clayey formations acting as traps. The anisotropy in shales is even more challenging as its imponderables range from a micro to a macro scale. This changes even further with factors like organic-hosted porosity and maturity. The inherent anisotropy in shales necessitates a multiscale examination. These multiscale discontinuities, coupled with parameters like organic matter and maturity, impact the elastic properties of the rocks, as evidenced by the ultrasonic evaluations.
 
In this study, acoustic characterization of samples was conducted using a benchtop ultrasonic wave propagation setup. The samples were clustered based on their colour and observed megascopic properties. Some sandstones were also included in the study to contrast sandstones with respect to shales. The wave velocities were determined for samples subjected to progressive heating up to 200°C (gas window), and the consecutive changes in the elastic parameters and resultant wave velocities of the rock were studied. Inputs from other methods utilizing different physics, such as FE-SEM, XRD were integrated to refine our interpretation. Notable changes were seen in wave velocities, especially in clusters with elevated organic content, while the density and Vp cross plots gave a good correlation with an R2 value of around 0.7.
This study advances our understanding of the impact of temperature on the elastic properties of shales, an aspect less explored than factors like stress and pressure. Thoroughly characterizing these parameters through acoustic methods provides critical insights into shale's storage capacity, carbon sequestration potential, and additional hydrocarbon recovery, specifically with respect to the Damodar Valley shales, aiding India to offset the projected peak of 4 GT CO2 emissions to achieve the carbon neutral goal promised at COP 26 and fulfilling UN Sustainable Development Goals.

How to cite: Jamwal, V. D. and Sharma, R.: Ultrasonic Evaluation of Shales vis-à-vis Temperature: A Case Study from Permian Damodar Valley Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-800, https://doi.org/10.5194/egusphere-egu24-800, 2024.

EGU24-1674 | ECS | Posters on site | ERE1.8

Using FracpaQ and seismic attributes to assess seismic scale fractures in carbonate reservoirs 

Hager Elattar, Richard Collier, and Paul W.J. Glover

Abstract: Fractured carbonate reservoirs are of great importance in the oil industry due to their significant role in global oil reserves and complex nature, where the majority of these reservoirs are naturally fractured, making them complex and challenging for oil recovery. The detection and characterization of fractures are essential for understanding the reservoir's petrophysical properties and hydrocarbon recovery potential as they play a critical role in reservoir performance. In this paper we have used 3D seismic from the Razzak field in the Western Desert, Egypt, with a specific focus on the Alamein dolomite reservoir. The reservoir holds significance due to its prolific oil-bearing nature, and featuring widespread lateral distribution in the northern Western Desert. Additionally, its contribution to an active Mesozoic petroleum system emphasizes its importance. Using Petrel software, the Alamein top and visible faults were identified, leading to the creation of a structural map illustrating the WSW-ENE axes of the Alamein's structural culminations in the southern part of the horst block. Owing to an extensional force during the Jurassic period with a NE-SW orientation, resulting from rifting, was evident, marked by the formation of normal faults associated with the opening of the Neotethys in the NE-SW direction. In the interpretation of 3D seismic data for Alamein dolomite reservoir, only one major listric normal fault was identified. However, the presence of minor faults or fractures, not easily discernible with conventional seismic techniques, is plausible. To address this, volume attributes were applied to detect subtle changes in seismic properties: (i) the curvature operation calculated the dip and azimuth angles, aiding in identifying structural complexities like faults and fractures, (ii) the maximum curvature value highlighted areas of steeply dipping or folded structures, (iii) Edge detection emphasized sharp boundaries, yet no hidden fractures or minor faults were revealed. The variance attribute yielded limited information, but Ant tracking on the variance cube effectively identified hidden minor faults and fractures. Incorporating the Ant track attribute into FRACPAQ software provided an objective methodology for quantifying fracture patterns, revealing NW-SE-oriented fracture segments in contrast to the WSW-ENE orientation of the major fault. Consequently, seismic attributes will unveil concealed fractures, and the application of FRACPAQ will prove effective in furnishing data on fracture orientation and length statistics.

Key words: FracpaQ; seismic attributes; fractured carbonate; Razzak field

How to cite: Elattar, H.A., Collier, R., and Glover, P. W. J.: Using FracPaQ and seismic attributes to assess seismic scale fractures in carbonate reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1674, https://doi.org/10.5194/egusphere-egu24-1674, 2024.

How to cite: Elattar, H., Collier, R., and Glover, P. W. J.: Using FracpaQ and seismic attributes to assess seismic scale fractures in carbonate reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1674, https://doi.org/10.5194/egusphere-egu24-1674, 2024.

Revealing the thermal structure of subsurface is crucial for various projects including geothermal energy exploitation, CCS and hydrocarbon exploration. For instance, temperature is one of the key physical underground parameters governing the type of Geothermal systems, whether injected CO2 remains in supercritical fluid stage and the depth of Golden Zone at where the hydrocarbon accumulations occur. Thus, understanding the temperature and geothermal gradient change in 1D-2D-3D sense indicates sweet spots and helps geoscientists to build more robust models to reduce the risks.

Based on this concept, this study aims to demonstrate the outcomes of a game-changer method which is the conversion of interval velocities into temperatures, thermal conductivities and heat flows by the help of recently proposed empirical relationships. As a case study, Northern Arabian Plate, SE Turkey is selected due to the neglection of thermal conditions in the area. Therefore, oil & gas industry-wide accepted methodologies have been applied to better understand thermal behaviour of the subsurface and how it has been controlled by regional tectonic edifices including large-scale thrust and strike slip faults.

In terms of methodology, as the first step, dynamic bottom hole temperatures of the wells have been converted into static ones by the help of “Temperature Analyser” web application. The converted temperature measurements have been used to generate regional temperature and geothermal gradient maps for every 500 meters. On the other hand, for 3D temperature models, seismic velocities have been converted into temperature cubes after calibration with the converted BHT measurements. Generated temperature cubes have been reflected on seismic sections to display lateral and vertical variations in temperature behaviour. It also allows the detection of meaningful temperature anomalies corresponding to possible fluid content.

The results reveal that abrupt temperature increase on maps directly coincides with the locations of oil producing fields. The same behaviour was noted globally both for hydrocarbon and geothermal fields. The change in temperature trend is also dominated by regional tectonics of the focus area. Large thrust fault systems act as boundaries for thermal anomaly regions while sinistral Mosul Fault Zone displaces and separates high temperature zones in a NW-SE sense. This movement can be easily associated with the Northern slip of the Arabian Plate since the continental collision occurred in the Miocene.

 

Based on these observations, the workflows and results of this study can be used for detailed investigation of subsurface geology, thermal conditions, and their effect on potential reservoirs for geothermal and CO2 storage. Workflows used to generate thermal models might allow the development of more efficient sustainable energy projects not only for the Northern sector of the Arabian plate but also for the other regions of the World.

How to cite: Uyanik, A.: Conversion of Interval Velocities into Thermal Models: A Game Changer Method for Subsurface Energy Exploitation Projects , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1739, https://doi.org/10.5194/egusphere-egu24-1739, 2024.

EGU24-2177 | Orals | ERE1.8

Short and long-term multiphase reactive transport processes during a pilot test of air injection into a sandstone gas storage facility 

Laurent De Windt, Irina Sin, Camille Banc, Anélia Petit, and David Dequidt

This study is based on unique field data on a 3-year pilot test during which air containing 8 mol% O2(g) was injected as a cushion gas into a natural gas reservoir, a carbonate-cemented sandstone aquifer located in the Paris Basin (France) [1]. The oxygen was fully depleted several months after injection completion, meanwhile CO2(g) was detected around 2–6 mol%; the pH decreased from 8 to 6, while reducing conditions shifted to mildly oxidizing ones with increasing concentration of sulfates in equilibrium with gypsum. After the test completion, the long-term evolution of the aquifer was assessed by a 15-year survey. The pH gradually returned to its near initial state and sulfates were reduced by 2 to 3 times. Data on the release of trace metals (Ba, Cu, Pb, Zn) during and after the test were also available.

Multiphase reactive transport models were developed on these field data using the HYTEC reactive transport code in 2D-reservoir configurations [1]. At the short-term scale, modeling focused on the gas-water-rock reactive sequence during the air injection: 1/ depletion of the injected O2(g) due to pyrite oxidation, 2/ leading to acidity production and dissolved sulfates, 3/ acidity buffering by calcite dissolution, 4/ followed by gypsum precipitation and CO2(g) exsolution. At the long-term scale, the modeling tackled with the progressive return to the baseline chemistry of the deep aquifer that was 1/ mostly driven by transport processes and 2/ to a lesser extent, slow water/rock chemical interactions.

These field-based models developed at short and long-term could be used as a workflow for other gas storage facilities, e.g. biomethane, compressed air, and CO2.

[1] Sin, I., De Windt, L., Banc, C., Goblet, P., Dequidt, D. (2023). Assessment of the oxygen reactivity in a gas storage facility by multiphase reactive transport modeling of field data for air injection into a sandstone reservoir in the Paris Basin, France. Science of The Total Environment 869, 161657.

How to cite: De Windt, L., Sin, I., Banc, C., Petit, A., and Dequidt, D.: Short and long-term multiphase reactive transport processes during a pilot test of air injection into a sandstone gas storage facility, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2177, https://doi.org/10.5194/egusphere-egu24-2177, 2024.

Kerogen is typically categorized in three types: type I is associated with lacustrine, type II associated with marine, and type III associated with terrestrial sources, respectively. The Kerogen type is a crucial factor affecting oil-generative properties as it significantly influences the initiation and potential for hydrocarbon generation in source rocks. Geoscientists traditionally use Rock-Eval pyrolysis to determine kerogen types, maturity, and pyrolysis reaction temperature (Tmax), and calculate hydrocarbon potential, essential factors in assessing oil reserves and understanding the oil window. Such method, however, has insufficient resolution and is time-consuming. In this study, we employ a temperature-dependent infrared (IR) spectroscopy method to precisely determine kerogen type, maturity, and Tmax. Specifically, our IR spectroscopy is combined with a numerical analysis model developed for the analysis of various organic matter samples. Through measurements of the IR spectra of samples at different temperatures (Heating-FTIR), we determine the maximum sedimentary burial temperature and the pyrolysis Tmax of kerogen. By applying the conversion formula by Shibaoka & Bennett (1977), (R0)a=Ra+btI*exp(cTm), we derive a virtual vitrinite reflectance, which is strongly correlated with our IR spectroscopy results, with insights into the maturation. This Heating-FTIR technique is a valuable tool for petroleum geology, facilitating the assessment of oil potential and maturity. Future refinement of the numerical model and improvement of the instrumentation are required to apply this technique to broader fields, such as sedimentary temperature for ancient geothermal gradient with better understanding of the sedimentary history.

How to cite: Chen, Y.-Y. and Chang, Y.-J.: Evaluation of Oil Source Rocks Using Temperature-dependent Infrared Spectroscopy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2449, https://doi.org/10.5194/egusphere-egu24-2449, 2024.

EGU24-3199 | ECS | Posters virtual | ERE1.8

 Using Quantitative Diagenesis to characterise and understand carbonate CCUS prospects 

Omar Mohammed-Sajed, Fraidoon Rashid, Paul Glover, Richard Collier, and Piroska Lorinczi

Recent years have seen the growth of new techniques that combine conventional stratigraphic and observational approaches to characterizing the type, scope, extent, timing and effects of diagenetic processes with petrophysical measurements of their rock microstructure. These Quantitative Diagenetic (QD) techniques can be used to predict post- and pre-dolomitisation porosities and permeabilities as well as trace the pathway of the diagenetically evolving rock through different stages of diagenesis that may turn a low-quality carbonate reservoir into a high-quality reservoir, or vice versa. While these new QD techniques are becoming useful for the characterization of hydrocarbon reservoirs, they are also extremely useful in the characterization of carbonate reservoirs for prospective CCUS use. This paper will briefly explain some of the main approaches to QD including dolomitisation prediction, petrodiagenetic pathways, reservoir quality fields, and Fracture Effect Index (FEI), before examining how they can be used to ensure that the prospective CCUS target reservoir is sufficiently well characterized that effective reservoir modelling can take place, and that the volume, flow and trapping of CO2 in the reservoir can be effectively monitored. Dolomitisation is known to be affected by the presence of CO2, with CO2 dissolving in aqueous pore fluids to form carbonic acid that directly affects porosity through dissolution and indirectly by affecting the dynamics of the dolomitisation process itself. There are two current QD methods for predicting the change in porosity upon dolomitisation. One is affected by both the direct and indirect effects, while the other is only sensitive to the indirect effects. Both the direct and the indirect effects can be plotted on a petrodiagenetic pathway. The presence of fractures is also a key aspect of how injected CO2 will flow in a CCUS reservoir. The QD parameter FEI describes the change in permeability of a rock concomitant upon a unit change in fracture porosity (i.e., what increase in flow results from a given increase on fracture porosity). This varies depending upon the degree to which fractures are connected and can be extremely useful in predicting the flow of CO2 within a fractured legacy carbonate CCUS prospect. In summary, QD approaches have the potential to provide those who need to characterise and model carbonate CCUS prospects with new and useful tools.

 

How to cite: Mohammed-Sajed, O., Rashid, F., Glover, P., Collier, R., and Lorinczi, P.:  Using Quantitative Diagenesis to characterise and understand carbonate CCUS prospects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3199, https://doi.org/10.5194/egusphere-egu24-3199, 2024.

EGU24-3696 | ECS | Posters virtual | ERE1.8

Simulation experiment evaluation and chemical kinetics prediction of the composition of n-alkanes components 

Song Bo, Haitao Xue, and Shuangfang Lu

          It is pivotal to predict the overall composition of subsurface oil and gas reservoirs to assess their fluidity, phase behavior, and recovery potential. Recognizing the significance of n-alkanes as key constituents of mature oil and gas, this study conducted a thermal simulation experiment of gold tube hydrocarbon generation on the source rock of Gulong Sag. The experiment included comprehensive analysis and measurement of the n-alkanes components in a representative sample. Subsequently, an empirical regression evaluation formula was established to evaluate the n-alkanes composition at various maturity stages. Furthermore, a chemical dynamics model for the formation of individual n-alkanes single molecule components was developed and calibrated based on the principles of chemical kinetics. Combined with the stratigraphic burial history and thermal evolution history of the target area, the distribution and evolution characteristics of n-alkanes components in different evolutionary stages of geological conditions can be quantitatively evaluated and predicted. Moreover, the phase behavior of n-alkanes components can be determined based on the evolution characteristics of these components. Experimental results indicate that the methane yield continues to increase with temperature under both heating rates. Additionally, the yield of n-C to n-C initially reaches its maximum with the temperature increase, and subsequently decreases. Furthermore, the hydrocarbon generation characteristics of n-alkanes follow a Gaussian distribution trend. The kinetic results demonstrate that the activation energy of n-alkanes falls within the range of 190-280 kJ/mol, while the distribution of pre-exponential factors is uneven. By considering the geological conditions, it has been determined that the light component in the Gulong Sag is currently experiencing a favorable generation period, whereas the heavy component has reached its peak formation stage, with some undergoing cracking. The oil and gas produced under these geological conditions exist as single-phase unsaturated fluids within volatile reservoirs. The evaluation value of the experimental regression formula, along with the predicted value from the dynamic model, aligns well with the experimental data, providing a solid foundation for the geological application of the model. Therefore, this research serves as a stepping stone towards furthering our understanding of hydrocarbon composition prediction, as well as evaluating phase behavior, mobility, and recovery of underground oil and gas in conjunction with geological conditions. 

How to cite: Bo, S., Xue, H., and Lu, S.: Simulation experiment evaluation and chemical kinetics prediction of the composition of n-alkanes components, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3696, https://doi.org/10.5194/egusphere-egu24-3696, 2024.

EGU24-3700 | ECS | Posters virtual | ERE1.8

Characteristics and factors controlling Permian shale gas reservoirs in the Hongxing area, Sichuan Basin, China 

BaiZHi Li, Nengwu Zhou, and Shuangfang Lu

Successful exploration of Permian shale gas in the Hongxing area has broadened shale gas exploration in the Sichuan Basin; however, the target layer is newly discovered, and reservoir research, which is key to shale gas exploration and development, is limited, thus restricting the screening and evaluation of the section containing the shale gas target layer. In this study, using organic carbon, whole-rock mineral analysis, scanning electron microscopy, low-temperature nitrogen adsorption, and other experimental methods, and by systematically identifying different lithofacies, we clarified the organic‒inorganic composition and microscopic pore structure characteristics of Permian shales in different phases of the Hongxing area and revealed the main factors controlling high-quality reservoirs and favorable lithofacies types for exploration. The results show that the shale in the study area mainly features six types of lithofacies: high-carbon siliceous shale (RS), high-carbon mixed shale (RM), high-carbon calcareous shale (RC), high-carbon muddy shale (RCM), low-carbon muddy shale (LCM), and low-carbon calcareous shale (LC). Organic pores are mainly present in RS, RM, RC, and RCM, while inorganic pores are dominant in LC and LCM. The pores are dominantly micropores, some mesopores are present, and very few macropores are present. Among them, the degree of micropore development is mainly affected by organic matter (abundance, maturity, and type), that of mesopores is mainly affected by clay minerals, and that of macropores is mainly affected by siliceous and clay minerals. There are obvious differences in the pore structure of different lithologies. The RS has the highest pore volume and specific surface area, with average values of 13.8×10-3 cm3/g and 21.57 m2/g, respectively, and its pore morphology is ink-bottle type, with pore diameters mainly <10 nm. The storage space of RM, RC, RCM, and LCM is moderate, with low-carbon argillaceous shale (LM) having the lowest.

How to cite: Li, B., Zhou, N., and Lu, S.: Characteristics and factors controlling Permian shale gas reservoirs in the Hongxing area, Sichuan Basin, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3700, https://doi.org/10.5194/egusphere-egu24-3700, 2024.

EGU24-3864 * | ECS | Orals | ERE1.8 | Highlight

From hydrocarbons to geothermal energy: a case study from the Dutch subsurface 

Annelotte Weert, Francesco Vinci, David Iacopini, Paul van der Vegt, Stefano Tavani, and Kei Ogata

The West Netherlands Basin, which has a long history in exploration as a former prosperous hydrocarbon province, is currently a geothermal hotspot. Being exploited since the 1950’s, most of its oil and gas fields are now in their final phase of production. In the past decade, interest shifted to sustainable energy sources. The geothermal industry in the area is developing quickly, helped by the legacy of the hydrocarbon industry: a wealth of publicly available seismic and well data. Currently, the area has 14 realized, and at least 3 projects in the development phase, with the Late Jurassic Nieuwerkerk Formation being the main target.

Conversely to petroleum systems, in which anticlines are the preferential target for hydrocarbon exploration, synclines are the most suitable sites for geothermal exploration. They offer higher temperatures with respect to the limbs and anticlines, and possible remaining hydrocarbons are not expected to be located inside the central portions of the synclines.

The West Netherlands Basin is a former rift basin that developed during the Mesozoic in the framework of the North Sea rift, and subsequently inverted during the Late Cretaceous. The Nieuwerkerk Formation was deposited during the last major rifting phase. Thus, the thickest packages of its fluvial-deltaic deposits are fault-controlled and commonly located in the synclines. The heterogeneity of fluvial reservoirs causes lateral and vertical quality variations in porosity, permeability and net-to-gross ratios. With the hydrocarbon industry focussing on the stratigraphic highs, there is only limited well data available for the central portions of the synclines.

With reprocessed 3D seismic data, our study uses an image processing approach, coupling traditional amplitude mapping with seismic attributes. This will help to reconstruct the evolution of the fluvial architecture of the Nieuwerkerk Formation over time. By tying the seismic with well data, a better prediction of the quality of the sandy bodies per location can be made. These results can be implemented in de-risking geothermal well planning across fluvial reservoirs in inverted rift basins.

How to cite: Weert, A., Vinci, F., Iacopini, D., van der Vegt, P., Tavani, S., and Ogata, K.: From hydrocarbons to geothermal energy: a case study from the Dutch subsurface, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3864, https://doi.org/10.5194/egusphere-egu24-3864, 2024.

EGU24-4657 | ECS | Orals | ERE1.8

Wave velocities as a proxy to forecast deformation during cyclic loading-unloading in porous reservoir rocks 

Debanjan Chandra, Barbara Perez Salgado, and Auke Barnhoorn

Porous reservoir rocks like sandstones have gained utmost important in the last decade as a potential sink for CO2. Most of the targeted reservoirs are depleted oil and gas fields, which has caprocks to ensure the containment of the injected CO2. Injecting CO2 into porous reservoirs increase the pore pressure, which therefore reduces the effective horizontal and vertical stresses. Depending on the pre-injection stress-condition and permeability of the reservoir, utmost care should be taken to define the upper limit of CO2 injection pressure, in order to prevent any permanent damage to the reservoir which can lead to leakage or induced seismicity. Lab-scale experiments provide key insights to the deformation behavior of reservoir rocks under different stress-conditions, which can be upscaled to understand reservoir scale processes. To simulate the stress perturbation caused by CO2 injection operations, we have subjected porous reservoir rocks (coreplugs) collected from different depths of offshore North Sea under cyclic axial loading and unloading with a confining pressure increment from 10-50 MPa between each cycle. The P and S wave velocities along the axial direction of the coreplugs were recorded in every 10 s to assess the change in wave properties during deformation. It was observed that during each loading cycle, wave velocities are highest at the elastic-plastic transition zone, which can be attributed to the compression of pores and closure of microcracks perpendicular to the loading direction. The wave velocities decrease sharply after the onset of plastic deformation, which can be attributed to the formation of microcracks in the coreplug due to increasing load. The static and dynamic Young’s modulus (E) of the coreplugs during each cycle of increasing confinement show linear increase. Plugs with lower porosity shows higher E with steeper increment at higher confining pressure. The correlation between the wave properties and mechanical response of the reservoir rocks under cyclic loading reveal that constant monitoring of wave velocities during CO2 injection can act as an efficient tool for monitoring stress-state of the reservoir, facilitating safer CO2 storage operations.

How to cite: Chandra, D., Salgado, B. P., and Barnhoorn, A.: Wave velocities as a proxy to forecast deformation during cyclic loading-unloading in porous reservoir rocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4657, https://doi.org/10.5194/egusphere-egu24-4657, 2024.

EGU24-5508 | ECS | Orals | ERE1.8

Cushion gas requirements for hydrogen storage in global underground gas storage facilities 

Mayukh Talukdar, Chinmaya Behera, Niklas Heinemann, Johannes Miocic, and Philipp Blum
To ensure system security and flexibility, storing excess renewable energy as hydrogen is considered an integral component of future energy systems. Cyclic underground hydrogen storage (UHS) with injection production cycles is planned to meet energy demand until new subsurface sites are prepared for storage. To avoid geomechanical risks caused by dynamic pressure fluctuations during cyclic storage, cushion gas is stored in such reservoirs. Cushion gas requirements for sites are still unknown. Therefore, in this study, we calculate the cushion gas requirement of various hydrogen storage sites using reservoir properties.
 
Hydrogen requires less cushion gas by volume than methane. Cushion gas volume in UHS sites varies with the initial reservoir pressure, gas flow rate, well tubing size, and erosional velocity. Cushion gas requirement decreases with increasing reservoir pressure, increasing gas flow, increasing well tubing size, and decreasing erosional velocity. In the studied sites, cushion gas volume ranged from a few % (0-5%) to 99% of the total gas volume. Shallow sites cannot store much hydrogen because of the high cushion gas %. On the other hand, sites deeper than 1100 m are unsuitable owing to insufficient structural trapping and enhanced biogeochemical reactions. Considering these factors, we report the optimum cushion gas volumes for various underground storage sites worldwide.

How to cite: Talukdar, M., Behera, C., Heinemann, N., Miocic, J., and Blum, P.: Cushion gas requirements for hydrogen storage in global underground gas storage facilities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5508, https://doi.org/10.5194/egusphere-egu24-5508, 2024.

EGU24-7216 | ECS | Posters virtual | ERE1.8

Land Use Change Characteristics in the Pan-Pearl River Basin in China from 1985 to 2020 

Wei Fan and Xiankun Yang

The changes in land use/cover are essential aspects of studying the impact of human activities on the Earth's surface and global transformations. In this study, utilizing the ESRI Global Land Cover data (ESRI land cover 2020) and the China Land Cover Data (CLCD), along with historical imagery from Google Earth, a comparative analysis scheme for land use classification results was designed. The CLCD dataset was updated, leading to the creation of a land use dataset for the Pan-Pearl River Basin spanning from 1985 to 2020. This dataset was then employed for the analysis of land use changes in the Pan-Pearl River Basin over the past 35 years.The results indicate:(1) Among the seven land use types, the most significant changes in area occurred in the following order: build -up land, cropland, forest land, grassland, shrubland, waterbody, and barren. Notably, there was a substantial increase in the areas of build-up land and forest land, while cropland, grassland, and shrubland experienced significant decreases. The waterbody’area showed a slight overall increase trend.(2) The major land use types undergoing changes varied among sub-basins, with the intensity of land use change ranked as follows: Pearl River Delta region(1.9%) > Coastal rivers in southern Guangdong and western Guangxi(0.20%) > Dongjiang River Basin(0.13%) > Hanjiang River Basin(0.12%) > Xijiang River Basin(0.10%) > Beijiang River Basin(0.08%) > Hainan Island region(0.02%).(3) Within the sub-basins of the Pan-Pearl River Basin, the most significant increase was observed in the area of built-up land, exhibiting a continuous expansion trend with a total increase of 12184 km2. This increase was primarily due to the conversion of cropland, forest land, and waterbody. The most significant decrease occurred in cropland, with a total reduction of 10435 km2, mainly transitioning to built-up land and forest land. The phenomenon of built-up land encroaching on cropland was particularly prominent, especially in the Pearl River Delta region. Forest land also showed a decreasing trend, mainly attributed to cultivation and the encroachment of built-up land. The reduction in grassland area was more pronounced in the Xijiang River Basin, primarily transforming into forest land, cropland, and built-up land. The study reveals that the rapid development of socio-economics and industry, coupled with an increase in residents' consumption levels, serves as the primary driving force behind land use changes in the Pan-Pearl River Basin. Additionally, land use and management policies play a crucial role as driving factors in the region's land use changes. This research aims to provide a scientific basis for formulating policies related to the region's land resources and land management, holding significant importance for preserving ecological balance and fostering sustainable development in the basin.

How to cite: Fan, W. and Yang, X.: Land Use Change Characteristics in the Pan-Pearl River Basin in China from 1985 to 2020, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7216, https://doi.org/10.5194/egusphere-egu24-7216, 2024.

EGU24-7761 | Posters on site | ERE1.8 | Highlight

Reutilising hydrocarbon wells as deep heat exchangers to decarbonise heating in the Northern Netherlands  

Johannes Miocic, Jan Drenth, and Pieter van Benthem

To meet the climate targets outlined in the Paris Agreement, European Green Deal, and the goal of reducing dependence on fossil fuel imports per the REPower EU Action, decarbonizing and reducing energy consumption in the heating and cooling sector is imperative. This sector, a major contributor to household energy use, plays a pivotal role in achieving sustainable energy goals.

Geothermal energy, particularly through geothermal doublets, stands out as an ideal solution for supplying energy for space heating and cooling. However, the inherent risks associated with fluid exchange with the subsurface make it scientifically or politically challenging in certain areas. Addressing this concern, deep borehole heat exchangers function as closed-loop systems, eliminating fluid exchange with the subsurface.

In this study, we explore the feasibility of repurposing existing oil and gas wells in the Northern Netherlands as deep coaxial borehole heat exchangers to provide heat to local communities. Utilizing analytical solutions, we calculate the thermal power output of 365 gas wells suitable for retrofitting. These wells exhibit bottom hole temperatures exceeding 80°C, capable of delivering temperatures above 60°C or thermal powers exceeding 800 kW, depending on flow rate and inflow temperature.

Our analysis includes assessing the proximity of well locations to high-density heat demand neighborhoods within a 6 km radius, facilitating the provision of supply temperatures for future local heat district networks. Notably, heat loss from well to neighborhood generally remains below 2°C, ensuring sufficient heating power supply to nearby residential areas. Several well clusters demonstrate significant heat over-supply, suggesting the potential for transporting excess heat to more distant locations. In cases where heat supply from wells is too low, in particularly in neighbourhoods with very low building efficiency rating (<E), heat pumps can be utilised to supply the needed energy.

Our findings indicate that repurposing existing hydrocarbon wells as coaxial heat exchangers offers a viable option for providing low-carbon heating to numerous residential areas in the Northern Netherlands. However, the geographical distribution reveals that not all high heat demand neighbourhoods have well sites in proximity, underscoring the importance of implementing a diverse heat supply strategy.

How to cite: Miocic, J., Drenth, J., and van Benthem, P.: Reutilising hydrocarbon wells as deep heat exchangers to decarbonise heating in the Northern Netherlands , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7761, https://doi.org/10.5194/egusphere-egu24-7761, 2024.

EGU24-8307 | ECS | Posters virtual | ERE1.8

Using machine learning to discriminate between mineral phases and pore morphologies in carbonate systems 

Wurood Alwan, Paul Glover, and Richard Collier

Digital rock models are becoming an essential tool not only for the modelling of fundamental petrophysical processes, but in specific key applications, such as Carbon Capture and Underground Storage (CCUS), geothermal energy exploration, and radioactive waste storage. By utilizing advanced imaging and simulation techniques, digital rocks provide indispensable insights into the porous structures of geological formations, crucial for optimizing CO2 storage, enhancing geothermal reservoir characterization, and ensuring the secure containment of radioactive waste. This abstract aims to present new advances using digital rocks to study these pressing environmental and energy challenges.

Estimating the physical properties of rocks, a crucial and time-consuming process in both the characterisation of hydrocarbon, geothermal and CCUS resources, has seen a shift from traditional laboratory experiments to the increasingly prevalent use of digital rock physics. A key requirement of many forms of pore structure image analysis is that they require binary images showing pore-space vs. non-pore space (mineral phases). These are typically obtained by thresholding grey scale SEM or X-ray tomographic images to separate the two phases. In this paper, we have adapted a 2D process-driven MATLAB model to generate synthetic porous media images, laying the foundation for simulating authentic SEM images. The objective of the computational framework outlined in this study is to train a machine-learning model capable of predicting various types of porosity. Drawing inspiration from recent advances in machine learning applied to porous media research, our approach involves the development of deep learning models utilizing Convolutional Neural Networks (CNN). Specifically, we aim to quantitatively characterize the inner structure of the 2D porous media based on their binary images through the implementation of these CNN models. This framework consists of: (i) Generating synthetic porous media images through a process-driven model, (ii) training a neural network that takes a labelled synthetic image as input and gives two types of porosity as output, (iii) whereupon the trained model can be applied to provide types of porosities for new images that are not in the training database. The generated data are divided into training, validation, and testing datasets. The training dataset optimizes CNN parameters for accuracy, the validation dataset aids in hyperparameter selection and prevents overfitting, and the testing dataset evaluates the predictive performance of the trained CNN model.

This research not only advances the understanding of fundamental geological processes but also plays a crucial role in optimizing the utilization of renewable energy sources such as geothermal and contributing to the effective management of carbon capture and storage initiatives.

How to cite: Alwan, W.S., Glover, P. W. J., and Collier, R.: Using machine learning to discriminate between mineral phases and pore morphologies in carbonate systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8307, https://doi.org/10.5194/egusphere-egu24-8307, 2024.

How to cite: Alwan, W., Glover, P., and Collier, R.: Using machine learning to discriminate between mineral phases and pore morphologies in carbonate systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8307, https://doi.org/10.5194/egusphere-egu24-8307, 2024.

EGU24-8973 | ECS | Orals | ERE1.8

Assessing earthquake focal mechanisms in the North Sea for risk mitigation of large-scale CO2 injections 

Evgeniia Martuganova, David F. Naranjo Hernandez, Daniela Kühn, and Auke Barnhoorn

Decarbonisation of the European economy represents one of the current challenges to both society and the energy sector. The advancement and further application of carbon capture and sequestration (CCS) technologies are crucial components of the EU’s effort to become climate-neutral by 2050. The success of CCS depends heavily on understanding the present-day stress field to anticipate reservoir and cap rock response to fluid injection. Despite its importance, many proposed carbon storage sites in the North Sea are located in areas with little to no borehole stress data available, presenting a significant challenge.

Within the ACT project SHARP Storage framework, we have addressed this gap by generating a comprehensive earthquake bulletin for the North Sea, revealing spatial clusters of seismic events with the majority of earthquakes with ML < 4. Focal mechanisms of earthquakes are excellent indicators of crustal dynamics, which are essential for assessing the present-day stress field. Therefore, to improve the understanding of the in-situ stress conditions, we created a comprehensive workflow to evaluate focal mechanisms based on data from the North Sea (Kettlety et al., 2023). First, we developed a routine for the seismological bulletin to aggregate the recorded earthquakes from international seismological centres. The following step included retrieval of the waveforms from data centres and quality control routines, which included dead channels check, exclusion of files with significant recording gaps and low signal-to-noise ratio, and corrections of errors in the station XML files. Then, a subset of data traces with sufficient quality was selected for moment tensor computations using a Bayesian bootstrap-based probabilistic inversion scheme (see Heimann et al., 2018). Using existing focal mechanism solutions for the North Sea region, we calibrated our processing routine and then applied it to selected earthquakes (after 1990, M > 3.5) to expand the existing focal mechanisms database.

The newly computed focal mechanism solutions provide valuable insight into the present-day stress field in areas outside the main hydrocarbon provinces and improve the risk assessment of ongoing and future CCS projects. Furthermore, we will release our processing workflow as an open-source package and a new focal mechanisms database of the North Sea to establish a standard processing routine that can be readily utilised for similar seismological studies.

How to cite: Martuganova, E., Naranjo Hernandez, D. F., Kühn, D., and Barnhoorn, A.: Assessing earthquake focal mechanisms in the North Sea for risk mitigation of large-scale CO2 injections, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8973, https://doi.org/10.5194/egusphere-egu24-8973, 2024.

EGU24-9206 | ECS | Orals | ERE1.8

Storage potential of CO2 by repurposing oil and gas-related injection wells in the Montney Play, northeast British Columbia, Canada 

Hongyu Yu, Bei Wang, Honn Kao, Ryan Visser, and Malakai Jobin

From 2005 to 2020, Canada achieved a 9.3% reduction in green house gas emission (69 Mt CO2 eq), meanwhile British Columbia witnessed a 5% increase (3.0 Mt CO2 eq) from 2007 to 2019. Exploiting unconventional oil and gas resources in northeast British Columbia (NEBC) has become the province’s second-largest source of greenhouse gas emissions. In pursuit of a cost-effective and seismic risk-aware approach for carbon emission reduction, this study evaluates the CO2 geological storage capacity in NEBC with a focus on repurposing existing injection wells for carbon storage.

We particularly emphasize the Montney and Debolt formations. These formations are the main targets of a diverse array of injection wells, including those for hydraulic fracturing, enhanced hydrocarbon recovery, and wastewater disposal. Three trapping mechanisms in the NEBC area are examined: physical and solubility trapping for wastewater disposal wells in the Debolt Formation, and physical and mineral trapping for hydraulic fracturing and enhanced recovery wells in the Montney Formation. Furthermore, we incorporate an assessment of seismic hazards, informed by the latest insights into injection-induced seismicity in NEBC, as a potential indicator of CO2 leakage risk.

Our findings underscore the favorable conditions of the Debolt Formation with lower seismicity hazard and a substantial CO2 storage capacity (19.3 Gt; ~284.4 years of CO2 emissions in BC). Depleted oil and gas reservoirs within the Montney Formation are also deemed suitable for CO2 storage, estimated at 1671.8 Mt (approximately 24.5 years), particularly in the Upper Montney due to its higher storage capacity and lower seismic risk.

Overall, this research offers an assessment of CO2 geological storage potential at the formation-scale in NEBC. The emphasis on well suitability and seismic risks effectively bridges the gap between the regional-scale geological assessments and site-scale engineering evaluations. It paves the path for future studies on addressing more practical topics related to the choices of project sites and injection strategies.

How to cite: Yu, H., Wang, B., Kao, H., Visser, R., and Jobin, M.: Storage potential of CO2 by repurposing oil and gas-related injection wells in the Montney Play, northeast British Columbia, Canada, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9206, https://doi.org/10.5194/egusphere-egu24-9206, 2024.

EGU24-9509 | ECS | Orals | ERE1.8

Quantifying flow reduction during injection of CO2 into legacy hydrocarbon reservoirs for CCUS 

Qian Wang, Glover Paul, and Lorinczi Piroska

In the development of hydrocarbon fields, it is becoming known that CO2 injection (which is sometimes done to improve hydrocarbon production) can cause pore blockage and wettability alteration by the promotion of asphaltene deposition. In hydrocarbon reservoirs, the result is poor oil recovery performance during carbon dioxide (CO2) injection. If CO2 is being injected into a legacy hydrocarbon reservoir (i.e., one that still contains residual oil) the same process will occur. Once again, the ability of fluid (this time supercritical CO2) to flow will be impeded, but it is also possible that asphaltene deposition will also reduce the overall pore volumes in which CO2 could otherwise be stored. In this work, the residual oil distribution and the permeability decline caused by organic and inorganic precipitation after miscible CO2 flooding and water-alternating-CO2 (CO2-WAG) flooding have been studied by carrying out core-flooding experiments at high pressures and temperatures in an artificial three layer system. For simple CO2 injection during CCUS operations, flooding experimental results indicate that the low-permeability layers retain a large oil production potential even in the late stages of production, which could impede CO2 emplacement and provide significant heterogeneity, while the permeability decline due to asphaltene precipitation is more significant in high-permeability rocks. In contrast, we found that CO2-WAG can reduce the influence of heterogeneity on the oil production, but it results in more serious reservoir damage, with permeability decline caused by CO2–brine–rock interactions becoming significant. In addition, miscible CO2 flooding has been carried out for rocks with similar permeabilities but different wettabilities and different pore-throat microstructures in order to study the effects of wettability and pore-throat microstructure on formation damage. Reservoir rocks with smaller pore-throat sizes and more heterogeneous pore-throat microstructures were found to be more sensitive to asphaltene precipitation, making these less attractive for CCUS reservoirs. However, rocks with larger, more connected pore-throat microstructures became less water wet due to asphaltene precipitation to pore surfaces, ultimately leading to a lower pore volume in which CO2 can be stored. Taken together, there may be a case for not simply injecting CO2 in CCUS operations, but alternating the CO2 injection with injection of water in order to stabilise CO2 flow and reduce formation damage by asphaltene precipitation.

How to cite: Wang, Q., Paul, G., and Piroska, L.: Quantifying flow reduction during injection of CO2 into legacy hydrocarbon reservoirs for CCUS, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9509, https://doi.org/10.5194/egusphere-egu24-9509, 2024.

Though global energy needs continue to grow, fossil fuels, and their associated CO2 emissions, are increasingly being opposed as our main source of energy. Instead, to achieve net zero greenhouse gas emissions goals, we are currently transitioning to more sustainable sources of energy, such as solar and wind power and geothermal energy, coupled with storage of waste, such as CO2. However, these new technologies come with their own challenges, as they continue to rely on (re-)use of the subsurface landscape. The intermittency of solar and wind power will require storage of renewably generated electricity. Hydrogen fuel has been marked as a potential energy carrier, enabling us to store large quantities of energy for prolonged periods of time, such as required to supply large industries or communities during winter months. To store this hydrogen fuel, the subsurface offers the largest storage space available, such as in (offshore) depleted hydrocarbon fields, but reproduction of the stored fluid is crucial. Geothermal energy production will require the extraction of hot fluids from depth and will often be performed in populated areas, close to the consumers, meaning that phenomena such as surface subsidence and induced seismicity are highly undesirable. The safe storage of CO2 for thousands of years also entails fluid injection, but containment is of vital importance to keep the CO2 out of our atmosphere. So though we have a vast history of exploitation of the subsurface through the oil and gas industry, which we can and should build upon, these new sustainable energy developments also pose their own, new challenges. While fluid production changes the physical equilibrium of the system, these new uses will also impact the chemical equilibrium through the injection of new fluids. Furthermore, containment and safety play an even bigger role than before to ensure the longevity of these new subsurface operations. In this contribution, I will outline what the challenges are that we are facing and how geoscientists can contribute to solving these challenges, across all areas from rock physics, geochemistry and hydrology, to sedimentology, structural geology and policy.

How to cite: Hangx, S.: Same same but different: the scientific challenges when re-using the subsurface for sustainable energy developments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12486, https://doi.org/10.5194/egusphere-egu24-12486, 2024.

EGU24-12846 | Posters on site | ERE1.8

Exploring the Relationship between CT Scanning Resolutions and Sandstone Porosity for CCS Applications 

Jyh-Jaan Steven Huang, Yao-Ming Liou, Arata Kioka, and Tzu-Ruei Yang

In the context of Carbon Capture and Storage (CCS), the porosity of potential storage formations is a critical factor. Our study explores this aspect using computed tomography (CT) to assess how different scanning resolutions impact the accuracy of porosity measurements. We employed three CT systems - Geotek RXCT (resolution ~20-150 μm), Bruker 1272 (resolution ~5 μm), and DELab μCT-100 (resolution ~9 μm) - to scan sandstone cores of varying porosities. The aim was to identify an optimal scanning resolution that balances detail with practicality for CCS evaluations.

This research addresses the challenges in high-resolution CT scanning, such as denoising effects that can alter accuracy, and the complexities of thresholding segmentation across various systems. Additionally, we examined the partial volume effect, crucial for interpreting pore sizes and distributions accurately.

Our preliminary results suggest that scanning resolution significantly affects the perceived porosity. Different resolutions uncover diverse aspects of pore structure, highlighting the importance of choosing an appropriate resolution. Advanced image processing techniques, including effective denoising and accurate thresholding, are vital for reducing errors in porosity measurement.

The study provides valuable insights into the use of CT scanning for CCS applications, emphasizing the need for a balanced approach in resolution selection and sophisticated image processing. These findings are instrumental in enhancing the reliability of geological evaluations for potential CCS sites, contributing to the broader efforts in carbon storage and climate change mitigation.

How to cite: Huang, J.-J. S., Liou, Y.-M., Kioka, A., and Yang, T.-R.: Exploring the Relationship between CT Scanning Resolutions and Sandstone Porosity for CCS Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12846, https://doi.org/10.5194/egusphere-egu24-12846, 2024.

EGU24-13835 | ECS | Posters on site | ERE1.8

Characterising functionalised nanoparticles for improving fluid flow for CCUS in legacy hydrocarbon reservoirs  

Louey Tliba, Afif Hetnawi, Farad Sagala, Robert Menzel, Paul Glover, and Ali Hassanpour

In recent years there has been rapid development of nanoparticles (NPs). Nanoparticles can be used both as a probe into restricted spaces, such as the pores within a reservoir rock, and as tools for altering wettability or deliberately blocking pore throats to enhance fluid movement in less connected pores. Silica nanoparticles can have functional surfaces allowing them to react specifically to oils or water. Nanoparticles can be used to enhance oil production by releasing oil on mineral surfaces and improving fluid flow. However, they also have the potential for improving CO2 flow in CCUS reservoirs while enhancing the pore volume available for CO2 storage. In this paper we evaluate the performance of different non-functionalised and functionalised nanoparticles for enhancement of oil production, CO2 emplacement and gas flow. Different forms of silica NPs have been made, either unfunctionalized, or functionalised with branched amino-based polymer (hydrophilic) or a silane-based agent (hydrophobic). Their stability has been characterised using a range of laboratory methods. The microscopic performance of the nanoparticles has been measured using contact angle measurements. Their ability to enhance oil production and CO2 emplacement has been tested using imbibition and drainage experiments. 

The contact angles, measured in the presence of brine, no modified silica NPs, branched amino-based polymer (hydrophilic) modified silica NPs and silane-based agent (hydrophobic) modified silica NPs showed contact angle values of approximately 110°, 116°, 124°, and 136°, respectively. These results show that introduction of nanofluids led to a change in substrate wettability from water-wet to strongly water-wet. Notably amongst the tested nanoparticles the Silane-based NPs demonstrated the highest hydrophilic surface. The spontaneous imbibition tests conducted on various sandstone cores revealed that silane-based NPs yielded the highest oil recovery rates among the tested NPs. Specifically, these nanoparticles showed an approximate 12% and 50% enhancement in oil recovery compared to non-modified silica nanoparticle, and branched amino-based polymer (hydrophilic) modified silica NPs. In summary, nanofluids have been shown to substantially improve the wettability alteration of the rock surface from oil-wet to water-wet, which can lead to improve the volume and flow characteristics of legacy CCUS prospects. Our future plan is to investigate the enhancement of carbon dioxide (CO2) solubility in brine through the utilization of the prepared nanoparticles, with the objective of advancing carbon capture technologies.

How to cite: Tliba, L., Hetnawi, A., Sagala, F., Menzel, R., Glover, P., and Hassanpour, A.: Characterising functionalised nanoparticles for improving fluid flow for CCUS in legacy hydrocarbon reservoirs , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13835, https://doi.org/10.5194/egusphere-egu24-13835, 2024.

EGU24-14959 | Orals | ERE1.8

TRANSGEO - Transforming abandoned wells for geothermal energy production 

Hannes Hofmann, Julie Friddell, Ingo Sass, Thomas Höding, Katrin Sieron, Max Svetina, Monika Hölzel, Robert Philipp, György Márton, Balázs Borkovits, Klára Bődi, Alen Višnjić, Tomislav Kurevija, and Bojan Vogrinčič

TRANSGEO is a regional development project that aims to explore the potential for producing sustainable geothermal energy from abandoned oil and gas wells in central Europe.  Composed of 11 partner organizations and 10 associated partners in 5 countries, TRANSGEO is developing a Transnational Strategy and Action Plan to address this technical and economic opportunity.  Our primary objective is to support rural communities and industries in the energy transition by providing tools and information that highlight sustainable redevelopment priorities and opportunities.

To reach this objective and promote the switch from fossil fuels to green energy, TRANSGEO is developing reuse procedures for five different geothermal technologies and validating them via numerical modelling, to assess their performance in repurposing existing hydrocarbon infrastructure and determine the optimal reuse conditions and configurations.  The five geothermal technologies are Aquifer Thermal Energy Storage, Borehole Thermal Energy Storage, Deep Borehole Heat Exchangers, Enhanced Geothermal Systems, and Hydrothermal Energy production.  The modelling studies focus on reference sites in our study areas, the North German Basin, the South German Molasse Basin, the Vienna Basin, and the Pannonian Basin.  Comparison of varying wellbore and reservoir parameters in the numerical modelling studies will provide input to a new online well assessment tool which will be available publicly to determine well suitability and guide planning for future reuse projects.  The online tool will be informed by a database of abandoned wells in Austria, Croatia, Germany, Hungary, and Slovenia and will include local reference data, such as geology, topography, heat demand, and utilities.  This will facilitate well reuse by matching candidate wells with local energy demand and heating networks.  Additional work on socio-economic and policy analyses will provide financial and liability information for the 5 different geothermal technologies, across the project countries.  Finally, the partnership will propose a legal policy and incentive framework to facilitate and expand reuse of abandoned wells for geothermal energy production and storage across central Europe.

TRANSGEO is co-funded by the European Commission’s Interreg CENTRAL EUROPE programme.

How to cite: Hofmann, H., Friddell, J., Sass, I., Höding, T., Sieron, K., Svetina, M., Hölzel, M., Philipp, R., Márton, G., Borkovits, B., Bődi, K., Višnjić, A., Kurevija, T., and Vogrinčič, B.: TRANSGEO - Transforming abandoned wells for geothermal energy production, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14959, https://doi.org/10.5194/egusphere-egu24-14959, 2024.

EGU24-16266 | ECS | Orals | ERE1.8

Geological characterization of the “Fonts-Bouillants” helium discovery - France 

Russier Emma, Géraud Yves, Hauville Benoît, Tarantola Alexandre, Beccaletto Laurent, and Diraison Marc

Geological characterization of the “Fonts-Bouillants” helium discovery - France

Russier E1,2, Géraud Y2, Hauville B1, Tarantola A2 ,Beccaletto Land Diraison M1

1 45-8 ENERGY, France

2 GeoRessources, University of Lorraine, France

3 BRGM, F-45060, Orléans, France

 

ABSTRACT

Helium is essential for the manufacturing of many of our daily commodities such as optical fibres, computers or cell phones (semiconductors and processors), medical use (MRI scanners) or in other more specific applications such as airlifts, leak detection, gas chromatography or diving. Nowadays, Europe imports 100% of its helium needs from overseas and is facing regular shortages, reason why 45-8 Energy embarked five years ago on helium exploration and production in Europe.

 

Helium is a noble gas mostly coming from the natural radioactive decay of Uranium and Thorium contained in the crust and the basement. Its migration and accumulation are strongly linked to a vector fluid that can be CO2, N2, CH4 or water. Helium and its vector fluids are then trapped and sealed in a rock reservoir.

 

The Fonts-Bouillants area is located at the southern edge of the Paris Basin at the vicinity of the French Massif Central and Limagne rift. The 45-8 Energy project aims to jointly produce He and CO2 from a gas which is naturally seeping through the major Saint-Parize fault (SPF).  Geological origin and migration pathway of He are therefore key questions to define the exploration guide, in particular to locate production wells to produce the seeping gas and process it. A multidisciplinary approach involving geology, geophysics, petrophysics and geochemistry has therefore been deployed.

 

Because geological context was hardly documented in this area, a wide range of geophysical data were acquired or reprocessed and coupled with field geology to build a regional geological model. The initial geological model was considerably updated and a hidden and thick Late Palaeozoic depocenter was especially highlighted below the Mesozoic series. Well data in nearby analogous basins as well as outcrops enabled rock collections to conduct petrophysical and geochemical characterization. The main reservoirs discovered currently are in Triassic and Jurassic sandstones, and fault like Saint-Parize fault acted as barrier and drain. 

Our outcrops petrophysical and geochemical study highlight the importance of Late Palaeozoic basin for the helium system:

  • As a potential rock source, with higher U-Th concentrations (3-13.5, 8-24 ppm) than typical crustal U-Th concentrations (1.8 and 7.2 ppm, [1]).
  • As a potential migration pathway and reservoir, with sandstones and conglomerates porosity higher than 20% and permeability higher than 100 mD.

 

Finally, gas sampling was performed in local natural springs, but also during well testing conducted in shallow boreholes which have encountered gas bearing reservoirs in the Mesozoic along the SPF. Helium generation system was modelled with geochemical data from the rocks and the fluids and from the volumetric capacity of the Palaeozoic basin.

 

Keywords: Helium exploration, Geophysics, Petrophysics, Geochemistry

Themes: Helium exploration

 

References:

[1] Krauskopf, K. B., & Bird, D. K. (1967). Introduction to geochemistry (Vol. 721). McGraw-Hill New York.

 

How to cite: Emma, R., Yves, G., Benoît, H., Alexandre, T., Laurent, B., and Marc, D.: Geological characterization of the “Fonts-Bouillants” helium discovery - France, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16266, https://doi.org/10.5194/egusphere-egu24-16266, 2024.

Natural gas storage is currently considered as one key pillar of the EU strategy to ensure security of energy supply. In view of CH4 storage, Oldenburg [1] demonstrated in a theoretical study that using CO2 as cushion gas instead of CH4 has the advantage of increasing natural gas storage capacities of geologic reservoirs by up to 30 %. This is due to CO2 undergoing a significant density change when its’ critical pressure is exceeded during CH4 injection. Kühn et al. [2] investigated a comparable scenario with CH4 gas storage in a closed cycle with CO2 in one reservoir to temporarily store and reuse wind and solar energy. However, the potential qualitative degradation of the stored CH4 due to mixing with the CO2 cushion gas has not yet been sufficiently addressed in terms of the impact of the modeller’s choice of diffusion coefficients. Hence, the present study focuses on a quantitative assessment of the mixing behaviour of CH4 and CO2 under consideration of dynamic binary diffusion coefficients in a reference numerical simulation benchmark [1,3]. The TRANSPORTSE numerical simulator [4,5] is used with dedicated measures to mitigate the initially high numerical dispersion, introduced by the benchmark’s relatively coarse grid discretisation. The simulation results show that the mixing region is substantially reduced if dynamic binary diffusion coefficients are applied instead of a global constant for both gas components. Consequently, it is demonstrated that previous numerical assessments of natural gas storage with a carbon dioxide cushion gas overestimate the simulated CH4-CO2-mixing area, and thus the calculated mixing losses. Hence, combined gas storage of CH4 and CO2 is more efficient than expected so far.

[1] Oldenburg, C. M. (2003) Carbon Dioxide as Cushion Gas for Natural Gas Storage. Energy Fuels 17(1), 240−246. https://doi.org/10.1021/ef020162b

[2] Kühn, M., Nakaten, N. C., Streibel, M., Kempka, T. (2014): CO2 Geological Storage and Utilization for a Carbon Neutral “Power-to-gas-to-power” Cycle to Even Out Fluctuations of Renewable Energy Provision. Energy Procedia, 63, 8044-8049. https://doi.org/10.1016/j.egypro.2014.11.841

[3] Ma, J., Li, Q., Kempka, T., Kühn, M. (2019) Hydromechanical Response and Impact of Gas Mixing Behavior in Subsurface CH4 Storage with CO2-Based Cushion Gas Energy & Fuels 33 (7), 6527-6541. https://doi.org/10.1021/acs.energyfuels.9b00518

[4] Kempka, T. (2020) Verification of a Python-based TRANsport Simulation Environment for density-driven fluid flow and coupled transport of heat and chemical species. Advances in Geosciences, 54, 67-77. https://doi.org/10.5194/adgeo-54-67-2020

[5] Kempka, T., Steding, S., Kühn, M. (2022) Verification of TRANSPORT Simulation Environment coupling with PHREEQC for reactive transport modelling. Advances in Geosciences, 58, 19-29. https://doi.org/10.5194/adgeo-58-19-2022

How to cite: Kempka, T. and Kühn, M.: Geologic CH4 storage with CO2 cushion gas: using dynamic binary diffusion coefficients instead of a global constant in numerical simulations is more precise and results in lower mixing losses, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17184, https://doi.org/10.5194/egusphere-egu24-17184, 2024.

Since the end of the XIX century, many wells have been drilled worldwide for both Oil & Gas exploration purposes. Most of them are now abandoned and subjected to mining closure because exhausted or sterile. In the new epoch of energy transition scenario, the possibility to adapt and reuse these existing boreholes to exploit geothermal energy seems very promising. In fact, considering that approximately 40% of the total costs for a new geothermal project are devoted to drilling activity, the possibility of repurposing abandoned oil and gas wells offers a wide range of applications and exploitation of underground heat uses. The drilled borehole available data (e.g., underground temperature, lithology) provide helpful information about the sub-surface reservoirs, reducing the mining risk level, and wells allow direct access to the sub-surface heat energy. However, to develop a commercially viable geothermal power/thermal generating system, one must consider several factors, i.e., available prospecting, drilling and reservoir technologies, energy costs in the area, and resource durability.

This research aims to analyze the potential and feasibility of deep closed-loop systems solutions for heat and power energy production in Italy, in areas characterized by both normal and anomalous geothermal gradients and the distribution of available abandoned oil and gas wells. A prominent result is the development of a workflow leading to the feasibility assessment of deep closed-loop systems development, based on the identification of suitable abandoned O&G wells through the geological and thermal underground characterization and wells construction characteristics (diameter, depth, borehole material). Furthermore, a sensitivity analysis of the main parameters affecting most of the retrofitting of abandoned wells for geothermal purposes is performed thanks to thermal FEM modelling.

Finally, identifying the possible end-users in a suitable case study area, this research work provides preliminary insights into the quantity of thermal energy and electric power that this technology could produce.

How to cite: Facci, M. and Galgaro, A.: Numerical sensitivity analysis of energy performance of geothermal deep closed loop heat exchangers derived from the reuse of abandoned oil and gas wells, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17674, https://doi.org/10.5194/egusphere-egu24-17674, 2024.

EGU24-18605 | Orals | ERE1.8

Modelling dynamics of sedimentary basins: using geological history to predict subsurface activities at large-scale 

Claude Gout, Marie-Christine Cacas-Stentz, Adriana Traby, and Nathalie Collard

The dynamics of sedimentary basins is a complex combination of synchronous generally non-linear processes. In these natural systems, fluids migration and associated transfers play a fundamental role, even more so as they represent resources that are or may become essential for human societies. One way of assessing the potential of sedimentary basins is to model their past behaviour numerically.

Basin models have been developed since the 1990s for the needs of the oil industry, with the initial aim of assessing the thermal history, i.e. the maturation and expulsion of hydrocarbons from source rocks with variable kinetics and initial composition. These models are used for hydrocarbon prospect assessment in a wide range of sedimentary basins. They have evolved with the integration of the simulation of compaction mechanisms and fluid migration by Darcean single-phase or multi-phase flows. Still with an operational objective in mind, one of these models has been extended to simulate the transport of thermal energy and chemical elements in fluids, thereby helping to assess the geothermal and large-scale storage potential of a basin. The explicit representation of faults and unconformities, as well as the calculation of seal or reservoir formation fracturing as a function of fluid pressures, enables the plumbing system to be represented on a basin scale. In this network of drains, single- or multiphase fluids carrying compounds can interact with the rocks, according to the principles of reactive transport. Some of these simulations are being experimented using AI techniques. In these digital experiments, elements tracking could be a true added value for basin’s dynamics understanding.

A coupled simulation of this kind, combining conductive and advective thermal physics, mechanics (particularly of porous media), the hydraulics of multiphase fluids in porous media, chemistry of reactive transport and even the impact of bioactivity on basin’s fluids, representing geological processes in the subsurface on a large scale, makes it possible to quantify mass and energy transfers in the past. The result is a physically balanced model of the current spatial distribution of pressure, stress, temperature, mass, solid or fluid elements.

These results can be useful both in economic applications for first-order assessment of the resources of any sedimentary basin and in the scientific field for defining the boundary conditions of more specialised models. Initial experiments demonstrating the use of multiphysics models on a basin scale for CCS applications and geothermal energy assessment will be shown.

How to cite: Gout, C., Cacas-Stentz, M.-C., Traby, A., and Collard, N.: Modelling dynamics of sedimentary basins: using geological history to predict subsurface activities at large-scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18605, https://doi.org/10.5194/egusphere-egu24-18605, 2024.

With the advancement of exploration theory and technology, deep and ultra-deep carbonate rocks have gradually become an important new field for the development of oil and gas resources. High-quality carbonate reservoirs have become the focus of attention for oil and gas exploration and research in deep and ultra-deep fields. The Tarim Basin is the largest intracontinental oil and gas basin in China. The thick carbonate strata developed in the Lower Paleozoic are the main layers for oil and gas exploration, and the Ordovician carbonate strata are the main oil and gas producing layers. The predecessors have studied the tectonic evolution, sedimentary background and rock types of the Ordovician in the Tarim Basin. Combined with the analysis of the sedimentary thickness, lithology distribution and seismic profile structure of the Early Ordovician, it is believed that the Lower Ordovician sedimentary period inherited the Cambrian sedimentary pattern and transformed it into a gentle slope sedimentary background with a 'uplift-sag 'pattern, with obvious differentiation. Under the sedimentary background of the gentle slope of the Penglaiba Formation, the three paleo-uplifts of southwestern, northern and central Tarim are inherited geomorphological highs, and the inner gentle slope tidal flat facies is developed. The thickness of the stratum is obviously thinner, and it is mainly developed to represent the tidal flat environment. The periclinal part around the paleo-uplift is the middle gentle slope, which is characterized by dolomite and limestone interbeds. The proportion of granular rocks is high, which is a favorable development area for granular beaches. In this study, the deep drilling cores of the Lower Ordovician Penglaiba Formation in the central Tarim Basin were taken as the key research object, and the lithofacies, reservoir characteristics and dominant reservoir control factors of dolomite reservoirs were systematically analyzed by using macro-micro, qualitative-quantitative reservoir petrology analysis methods. Through research, it is clear that the rock types of the Lower Ordovician Penglaiba Formation in the central Tarim Basin are mainly crystalline dolomite and ( residual ) granular dolomite, and also contain a small amount of limestone, siliceous rocks and transitional rocks. There are various types of reservoir space, mainly including non-fabric selective dissolution pores, intercrystalline pores and various fractures. Combined with previous studies on the genesis and diagenetic evolution of the Lower Ordovician dolomite in the Tarim Basin, it is considered that the development of high-quality dolomite reservoirs in the Lower Ordovician Penglaiba Formation in the central part of Tarim Basin is controlled by many factors. It is the result of a combination of favorable sedimentary facies belts, short-term sea-level changes, exposure and dissolution, early dolomitization, and late tectonic hydrothermal adjustment and transformation.

How to cite: Li, X. and Xu, Q.: Development characteristics and controlling factors of deep dolomite reservoirs of Lower Ordovician in Tazhong area, Tarim Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20142, https://doi.org/10.5194/egusphere-egu24-20142, 2024.

Seismic data integration plays a pivotal role in enhancing the capabilities of geological modelling

software. Our current research focuses on the improvement of seismic interpretation tools within the

PZero software in the framework of the Geosciences IR project lead by the Italian Geological

Survey GitHub - andrea-bistacchi/PZero. The objective is to seamlessly incorporate seismic data

into the geological modelling workflow, enabling more comprehensive and accurate models of

subsurface structures.

The initial phase of our work involved using various libraries to import and analyze seismic

datasets, either 2D or 3D within the PZero framework. We have successfully achieved the

importation of SEGY files into PZero, marking a significant milestone in our efforts. Integrating

seismic data is a crucial step that sets the foundation for constructing detailed geological models,

allowing us to enhance our understanding of subsurface geological features.

Soon, our research trajectory aims to develop advanced algorithms for stochastic simulation tailored

explicitly for modelling clastic sedimentary alluvial plains. The ongoing work includes developing

advanced stochastic simulation algorithms tailored for modelling clastic sedimentary environments,

relevant to both conventional energy resources and emerging sustainable energy storage solutions.

These advancements in seismic data integration and simulation within PZero will significantly

contribute to the field of reservoir modelling. They provide a robust framework for predicting the

behavior of subsurface energy storage systems, which is pivotal in the transition to a low-carbon

energy future.

How to cite: Hussain, W. and Bistacchi, A.: Advancements in Seismic Data Integration and Stochastic Simulation for Geological Modeling in PZero, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22365, https://doi.org/10.5194/egusphere-egu24-22365, 2024.

EGU24-2809 | Posters on site | ERE1.9

A small coil transient electromagnetic system for quick subsurface mapping  

Pradip Maurya, Esben Auken, and Thue Bording

Transient Electromagnetic (TEM) methods are widely used in near-surface geophysical exploration. Traditional ground-based TEM systems utilize large transmitter loops (25x25 to 50x50 m²) to investigate depths between 200 and 300 meters, yielding 15-20 soundings per day. To enhance efficiency in shallower investigations (0 - 100 m), we introduce a compact TEM system with a small coil setup for rapid deployment and mobility, increasing data collection rates along extensive transects.

 

The novel system comprises a 3x3 m transmitter loop with two turns and an equivalently sized offset receiver loop with four turns, separated by 10 m to minimize coil coupling and ensure unbiased signals. Operating as a single-moment setup, it achieves a peak current of 5 Amp or 10 Amp, turning off in approximately 7 µs. Unbiased measurement begins at 10 µs post turn-off, extending to a late gate of 3 ms. Both transmitter and receiver are integrated into a portable unit powered by lightweight lithium-ion batteries. A dedicated mobile application for Android and iOS devices controls the system, facilitating real-time monitoring of data curves and system parameters like current and temperature.

With this system, two people can collect a 400 m profile in under 60 minutes, significantly faster than Electrical Resistivity Tomography (ERT) methods. The presentation will cover the system's layout, operational methodology, depth capabilities, and validation against the Danish National TEM Test Site. Comparative analyses will underscore its efficiency and effectiveness in aquifer layer mapping, offering a compelling alternative to traditional ground-based systems.

How to cite: Maurya, P., Auken, E., and Bording, T.: A small coil transient electromagnetic system for quick subsurface mapping , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2809, https://doi.org/10.5194/egusphere-egu24-2809, 2024.

EGU24-5979 | Posters on site | ERE1.9

Time-domain denoising of CSAMT data base on long short-term memory 

Zhiguo An, Bingcheng Xu, Ying Han, and Gaofeng Ye

Controlled-source audio-frequency Magnetotellurics method (CSAMT) partially overcomes the drawbacks of weak natural field signals. However, substantial interference is an inevitable part of field surveys in practice, which negatively impacts signal quality. We require new denoising techniques since traditional techniques, such as Fourier transformation, which compute apparent resistivity directly from frequency-domain data, are insufficient in our situation. CSAMT denoising research is currently lacking, nevertheless. This research proposes the use of long short-term memory (LSTM) neural networks to denoise CSAMT signals in the time domain, given their good performance in processing Magnetotelluric (MT) data as shown by prior studies. We seek to directly extract the desired frequency signal for denoising from the time series data, in contrast to conventional denoising techniques. Since noise and target frequency signals are mixed together in MT data, the only way to suppress noise is to find the characteristics of the noise in the time series. CSAMT, on the other hand, differs from MT in that it uses an artificial transmitting source and fixes the valid signal frequency within a temporal window. This makes it possible to extract target frequency signals directly without taking into account the intricate properties of noise. In order to complete the noise suppression job, we created a neural network in this study that is based on bidirectional LSTM. This method was able to partially handle the difficulty of denoising when the data's SNR falls below 0 dB and, on average, enhance the signal-to-noise ratio (SNR) of CSAMT data by roughly 20 dB after executing both simulated and measured data testing.

How to cite: An, Z., Xu, B., Han, Y., and Ye, G.: Time-domain denoising of CSAMT data base on long short-term memory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5979, https://doi.org/10.5194/egusphere-egu24-5979, 2024.

EGU24-7179 | Posters on site | ERE1.9

Early Detection of Coal Fire inside the Coal Stock Pile by 4D ERT Monitoring 

Myeong Jong Yi, Soocheol Jeong, and Seungwook Shin

Coal-fired power plant requires huge storage of coal. During the storage of coal, heat is accumulated inside the stock piles and eventually results in the self-combustion or coal fire, which is a very serious problem in the fuel management and environmental aspect of the power plant facilities. To detect and forecast the coal fire, various methods had been suggested but there are no proven early warning technology until today. Since the resistivity of the coal is strongly affected by temperature, we suggested the ERT (Electrical Resistivity Tomography) monitoring technology to identify the heat accumulation inside the coal stock pile, which can eventually provide an early warning method of coal fire in the power plant facilities. To prove the technology, we prepared a small scale coal stock pile and electrodes were placed on the bottom of the stock pile. In the inside of the coal pile, temperature was continuously increased by using heating tools and ERT monitoring data were acquired for a few days until real coal fire take place on site. The whole ERT monitoring data were processed and we tried the 4D inversion to obtain changes of 3D resistivity distribution with temperature changes. In the 4D inversion results, we could identify the systematic change of resistivity values due to the heating process. Although resistivity is increased in the very early heating stage, increased resistivity is evident with the increase of coal temperature until self-combustion of coal. Therefore, we could prove that 4D ERT monitoring technology is a very promising method to detect and forecast the coal fire in the power plant facility.

How to cite: Yi, M. J., Jeong, S., and Shin, S.: Early Detection of Coal Fire inside the Coal Stock Pile by 4D ERT Monitoring, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7179, https://doi.org/10.5194/egusphere-egu24-7179, 2024.

EGU24-9430 | ECS | Posters virtual | ERE1.9

Characterization of contaminated site using electrical resistivity and induced polarization methods 

Jian Meng, Teng Xia, Xinmin Ma, Ruijue Zhao, and Deqiang Mao

Soil and groundwater contamination has been widely concerned because of its impact on industrial, agricultural production, and even human health. Accurate delineation of contaminant distribution is the basis for successful remediation strategies. Traditional drilling based methods are costly and less efficient. Geophysical methods, particularly electrical resistivity (ERT) and induced polarization (IP), are sensitive to soil and groundwater contamination and have been proven very effective. However, there were still some pressing issues to be resolved, such as IP mechanism of contaminant, data acquisition, inversion strategies and monitoring system. In this study, we proposed the conceptual model of IP response for LNAPLs in-situ remediation process based on laboratory columns and sandboxes IP measurements, and quantified the effect of contaminant removal on IP parameters. In addition, the IP data acquisition method were improved for contaminated site surveys, doubling the detection depth and significantly increasing the IP data quality. Moreover, we propose a refined structure-constrained method that updates the smooth weights of all eight elements surrounding a boundary element using three different magnitudes. Combined with the joint interpretation of multisource data, detection accuracy was improved and the number of boreholes was reduced. We have applied ERT and IP techniques to more than 30 contaminated sites and proved their effectiveness.

How to cite: Meng, J., Xia, T., Ma, X., Zhao, R., and Mao, D.: Characterization of contaminated site using electrical resistivity and induced polarization methods, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9430, https://doi.org/10.5194/egusphere-egu24-9430, 2024.

The Badain Jaran Desert, located in the western part of the Inner Mongolia Autonomous Region in China, distinguishes itself from typical deserts by its abundance of lakes and rich groundwater reserves. At the Badain Jaran Desert, 153 magnetotelluric sounding stations have been explored to perform one-dimensional and three-dimensional inversion analyses of the collected magnetotelluric dataset. The results of one-dimensional inversion at each sounding station, where the top interface of the first underground low-resistivity layer is less than 400 meters, were used to build a map of the potentiometric surface level of the study area. This map aligns closely with the findings from hydrological surveys. The three-dimensional resistivity model indicates the existence of a conductive layer at the deep of 2-3 km, interpreted as a sandstone-confined aquifer, located between the mountain areas surrounding the Badain Jaran Desert and its clusters of lakes. 
Moreover, there is an almost vertical conductive zone underneath the lake cluster, which is interpreted as the discharge area of the confined aquifer. This zone is related to the upward flow of deep groundwater through fractures, replenishing both the lakes and the shallow groundwater, while the surrounding mountainous regions of the desert act as the recharge areas for this confined aquifer. Finally, an estimation of the volumetric percentage of saline fluid in the confined aquifer was derived based on the electrical conductivity model of pore-fluid saturated sandstone, yielding the saline fluid content that meets the resistivity/conductivity range conditions of the confined aquifer.

How to cite: Yi, X., Ye*, G., Jin, S., Wei, W., and Zhang, Y.: Groundwater Recharge Mechanisms in the Lake Clusters of the Badain Jaran Desert and the Salinity of Confined Aquifers Based on the Electrical Conductivity Model of Pore-fluid Saturated Sandstone, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15176, https://doi.org/10.5194/egusphere-egu24-15176, 2024.

EGU24-15575 | ECS | Posters on site | ERE1.9

Insights into geological and hydrogeological characteristics using airborne geophysical investigations of former opencast lignite mining areas 

Elisabeth Schönfeldt, Olaf Cortes Arroyo, Marcus Fahle, Bernhard Siemon, Silvio Janetz, and Erik Nixdorf

The region Lusatia in northeastern Germany, which is located about 100 km south of Berlin, is strongly affected by over a century of both former and on-going opencast lignite mining. Although, there is an abundance of borehole data from former excavation surveys both varying data quality and heterogeneous coverage is a challenge for deriving spatially continuous subsurface properties. To overcome these obstacles we combined airborne geophysical investigations with borehole data. Different machine learning-algorithms (Random Forest and K-means) are used to determine spatially and depth-related insights into the variability of geological and hydrogeological characteristics. An aeroelectromagnetic (AEM) survey was carried out in summer 2021 using BGR’s (German Federal Institute for Geosciences and Natural Resources) helicopter, which covered flight lines of 1680 km in an area of about 200 km². First results show that the machine learning approach can predict fine-grained sediments (clay and silt) in untrained areas and can distinguish between clusters of mining-affected regions and undisturbed ones. The results of the study will be further used to improve the parameterization of existing regional groundwater flow models to address challenges of water allocation in the region of Lusatia.

How to cite: Schönfeldt, E., Cortes Arroyo, O., Fahle, M., Siemon, B., Janetz, S., and Nixdorf, E.: Insights into geological and hydrogeological characteristics using airborne geophysical investigations of former opencast lignite mining areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15575, https://doi.org/10.5194/egusphere-egu24-15575, 2024.

EGU24-15611 | ECS | Posters on site | ERE1.9

The first application of a new 3D octree finite element inversion framework to CS/MT data 

Cedric Patzer, Longying Xiao, and Jochen Kamm

At GTK we are currently developing the entire workflow of the controlled source EM (CSEM) method, ranging from data acquisition to time series processing to modelling and inversion. Part of this work is the development of a 3D modelling and inversion framework, which is mostly done within the DroneSOM project. The flexible implementation allows not only for modelling and inversion of semi-airborne drone EM data, but also land-based CSEM/MT data. The forward problem is solved using the finite element method on hexahedral meshes. We separate forward and inverse mesh using octree mesh refinement. This helps in solving the trade-off between the required accuracy in the forward modelling and computational cost. It is also a great tool to combine different multiresolution EM data (e.g., CSEM and MT) in a single comprehensive inversion framework. This work will focus on first applications of land-based CSEM and (CS)MT.

In 2022 we collected controlled source MT data using a grounded electric dipole transmitter along the Koillismaa ultra-mafic intrusion in North-Eastern Finland. Despite transmitter receiver offsets of 3-5 km far field condition does not apply for frequencies below 4kHz, which permits the use of standard MT inversion. Here we show first inversion results of these data using our new EM inversion routine taking the transmitter position into account. In addition to the active source MT data, we also collected conventional MT data on a larger scale crossing the Koillismaa intrusion. Our inversion routine also allows the inversion of MT data. We are thus showing first inversion results of joint inversion of both datasets. 

How to cite: Patzer, C., Xiao, L., and Kamm, J.: The first application of a new 3D octree finite element inversion framework to CS/MT data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15611, https://doi.org/10.5194/egusphere-egu24-15611, 2024.

EGU24-18165 | ECS | Posters on site | ERE1.9 | Highlight

Mapping Subsurface Conductivity: Challenges and Progress in Italy's MARGE Project 

Giulia Pignatiello, Igino Coco, Michele De Girolamo, Manuele Di Persio, Fabio Giannattasio, Valerio Materni, Luca Miconi, Massimo Miconi, Giovanna Lucia Piangiamore, Gerardo Romano, Valentina Romano, Lucia Santarelli, Vincenzo Sapia, Sabina Spadoni, Simona Tripaldi, Roberta Tozzi, Agata Siniscalchi, and Paola De Michelis

In Italy, the MARGE initiative, an abbreviation for Geoelectromagnetic Risk Map for Central Italy, strives to create an extensive map of subsurface electrical conductivity by analyzing natural electric and magnetic fields.

Led by the National Institute of Geophysics and Volcanology in collaboration with the University of Bari and the Institute of Environmental Analysis Methodologies at CNR, his project involves establishing measurement points distributed on a grid spaced approximately 50 km apart.

However, this endeavor faces significant challenges in the central region of the Italian peninsula due to extensive urbanization, numerous electromagnetic disturbances from railways and high-voltage power lines, and challenging topography, making finding suitable land parcels a complex task.

The MARGE project aims to gather broad-band and long-term magnetotelluric data, focusing on two primary objectives: utilizing magnetotelluric data to outline large-scale lithospheric structures in the Central Apennines and developing maps of the geoelectric field in Central Italy to support Space Weather modeling and critical infrastructure vulnerability analysis.

Presenting our initial findings, we discuss encountered challenges and potential solutions identified in this ongoing project.

How to cite: Pignatiello, G., Coco, I., De Girolamo, M., Di Persio, M., Giannattasio, F., Materni, V., Miconi, L., Miconi, M., Piangiamore, G. L., Romano, G., Romano, V., Santarelli, L., Sapia, V., Spadoni, S., Tripaldi, S., Tozzi, R., Siniscalchi, A., and De Michelis, P.: Mapping Subsurface Conductivity: Challenges and Progress in Italy's MARGE Project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18165, https://doi.org/10.5194/egusphere-egu24-18165, 2024.

EGU24-19540 | ECS | Posters on site | ERE1.9

Uncertainty estimation of conductive thin plates parameters through a Bayesian approach 

Alessandro Vinciguerra, Guy Marquis, Jean-François Girard, Grant Harrison, and Elodie Williard

The uranium deposits of the Athabasca basin (Canada) represent one of the world’s highest-grade uranium resources. They are unconformity-related type at the base of relatively flat-lying sequences, where faults acted as circulation paths for hydrothermal fluids. The fault zones often contain graphitic mineralization and hence represent a valuable exploration guide of small lateral extension but detectable by electromagnetic (EM) surveys. Time-domain EM (TEM) is the method of choice for uranium exploration in the Athabasca, and taking into account the frequencies involved we can approximate the graphitization along the fault as a conductive thin plate.

To better determine the geometry of the deposit, it might be crucial to recover the subsurface resistivity and the geometric parameters of the plate (position, dip, depth, azimuth etc.). Moreover, the assessment of the uncertainty associated to the parameters can help to evaluate the reliability of geological models and to guide the subsequent drilling activities.

A quantitative approach consists of employing Bayesian inversion algorithms, which allows to exploit the prior information available. Indeed, Bayesian inversion algorithms aim to solve the inverse problem statistically returning the posterior probability density function (ppdf). In particular, they are based on the Bayes theorem, which relates the prior information (e.g. from geological and petrophysical models) with the likelihood function to assess the posterior probability density function and thus the uncertainty. We implement the Differential Evolution Markov Chain algorithm (DEMC), a multi-chain approach that integrates the Metropolis selection rule with population evolution to sample the ppdf. The chains run in parallel and each current model is updated drawing two other chains and exploiting the models at the previous iteration. After an initial stage of burn-in, the algorithm reaches the stationary regime where the chains start sampling the ppdf resulting at the end in an ensemble of models. From these models the moments of first and second order (mean and variance) are computed obtaining the uncertainty of the inverse problem solution. As forward operator we employ the LEROI forward code developed by CSIRO (AMIRA), which computes the TEM response of one or more conductive 3D thin plates embedded in a horizontally layered earth.

In this work we propose the DEMC inversion of TEM data as a tool to assess thin plates parameters and uncertainty in the context of uranium exploration.

 

How to cite: Vinciguerra, A., Marquis, G., Girard, J.-F., Harrison, G., and Williard, E.: Uncertainty estimation of conductive thin plates parameters through a Bayesian approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19540, https://doi.org/10.5194/egusphere-egu24-19540, 2024.

EGU24-20965 | ECS | Posters on site | ERE1.9

Development of 9000 m level hadal OBEM 

Sixuan Song, Ming Deng, Zhen Sun, Xianhu Luo, and Kai Chen

Taking the sea area near the southern part of the Mariana Trench as a typical area is crucial for deep structural research in marine geology and geophysics. The magnetotelluric (MT) method has advantages such as large detection depth, sensitive to low resistance reactions, low cost, and high efficiency. The application of MT in deep water requires instruments with high reliability and stability, low noise, wideband, low power consumption, and miniaturization. The ocean bottom electromagnetic receiver (OBEM), as one of the important instruments for MT in deep water observation, its performance directly affects the quality of detected data.

In response to the shortcomings of the existing 6000 m level OBEM, there is an urgent need to develop a 9000 m level hadal OBEM. According to the requirements, we have focused on overcoming the challenges of weak E-field measurement technology, low-power and low-noise M-field measurement technology, low-power underwater acoustic release technology, and water surface large-scale recycling technology. We have achieved lower noise, longer underwater operation time, and efficient operations, providing reliable and stable instruments for hadal MT observation.

We have developed a chopper amplifier that matches deep water E-field sensors, analyzed the causes of injected charges, and adopted a scheme that combines peak filtering technology and dead zone technology to suppress residual misalignment generated during the chopper modulation, effectively reducing 1/f noise in the circuit, expanding the input range, and improving input impedance.

An orthogonal fundamental mode fluxgate based on digital demodulation is developed. Digital closed-loop real-time processes such as high-precision ADC, digital synchronous demodulation, digital integration, and high-precision large dynamic range DAC are used to reduce the switching charge noise introduced by analog circuits. Developing adaptive closed-loop feedback control algorithms to achieve fast feedback compensation with low noise and large dynamic range can help improve key parameters such as noise bandwidth, and input range of sensors.

We adopt a deep-water acoustic release system, pressure-resistant acoustic transducer, and control module prototype. Hydroacoustic communication controls the opening of the constant current source and the electrocorrosion decoupler. This solution reduces the size of the instrument and only relies on a single glass ball to achieve the floating of the instrument. The system integrates commands such as status query, electrocorrosion on and off. The status information includes distance, electrocorrosion status, battery voltage, etc. The propagation distance of acoustic signals is greatly increased, improving the success rate of underwater acoustic communication.

The glass ball is equipped with a beacon module, which is controlled by acoustic signals to activate the AIS, achieving real-time transmission of the OBEM position. Besides, high-power LED flashing is controlled to facilitate nighttime recycling and further reduce the cost of offshore operations.

In August 2023, 5000 m level test was conducted in the southern South China Sea. It is preliminarily verified the MT measurement, which has been improved in terms of low power consumption, low noise, and adaptability to deep sea. In the future, we will conduct test verification in deeper sea.

How to cite: Song, S., Deng, M., Sun, Z., Luo, X., and Chen, K.: Development of 9000 m level hadal OBEM, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20965, https://doi.org/10.5194/egusphere-egu24-20965, 2024.

At present, we are using commercial ground penetrating radar (GPR) to inspect tunnel walls, conduct an underground geological structure assessment and anticipate geology behind the tunnel face. A variety of metal objects, include portal frame, forklift, and excavator, can cause back reflection in the GPR profile during the test in the tunnel. Typically end users of GPR are unable to appropriately interpret the GPR profile because they are unware of what is actually coming from back reflection in the air and projection into the ground penetrating radar profile or from subsurface. They really need some method to identify real reflection signals from underground sources.

The GPR antenna transmits electromagnetic (EM) waves that can travel all space, including the air, the interface between the ground and the air, and the subsurface. During EM travel in the air, there is some back reflection from the air object to be recorded in the GPR profile during data collection in the field. We need to measure and recognize and elimate this back reflection interference noise. We have made electromagnetic waves absorbent block configuration for the GPR antenna that can complete cover the GPR antenna. We have done the comparative experiments tests with and without electromagnetic waves absorbent block have been conducted in the field, the results show that, without this block, GPR profile recorded many back reflection from the air objects, while the GPR antenna with covering electromagnetic waves absorbent block can only record the refection from surbsurface during data collection in the field, and it is clear GPR profile. This allows the GPR end user direct interpret the GPR profile only with reflection from surbsurface as it may completely eliminate back reflection from the air object.

How to cite: Deng, X.: A method to collect clear profile with Ground Penetrating Radar in tunnel, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21417, https://doi.org/10.5194/egusphere-egu24-21417, 2024.

EGU24-21924 | Posters on site | ERE1.9

Measuring Induced Polarization signals from deep seated magma chamber – preliminary results from a pilot survey in Finland 

Bitnarae Kim, Jacques Deparis, Mathieu Darnet, Francois Bretaudeau, Simon Vedrine, Julien Gance, Jochen Kamm, Uula Autio, Cedric Patzer, and Suvi Heinonen

In this study, we conducted an extensive geophysical survey to explore the potential of electrical resistivity methods in delineating deep ore deposits within between Koillismaa Intrusion and Näränkävaara intrusion, northeastern Finland. Preliminary investigations in 2022, including magnetic, gravity and audio-magnetotelluric (AMT) methods, along with drilling, uncovered significant anomalous structures in the survey area. Subsequent drilling of an exploration well provided positive lithological indications of a ultramafic igneous rock at more than 1.5 km depth, which are very likely of the same age as the layered intrusions in the area. Borehole data indeed revealed that the Archaean basement gneiss extends down to approximately 510 m, underlain by a granite dyke with interspersed thin layers of pyroxenite and peridotite. Notably, peridotite layers around 1500 m depth exhibited distinct magnetic and IP responses in core data.
We employed electrical methods at the site, including electrical resistivity tomography (ERT) and induced polarization (IP). To cover a large-scale area, 25 transmitter dipoles, each 1 km long and using three different transmitter systems, were deployed and data were recorded at 119 receiver stations. This work presents the acquisition and preliminary results from the ERT-IP surveys. During the processing of ERT and IP data, we utilized full time-series data recorded across the four lowest main frequencies (from 0.0625 Hz to 8Hz) to capture voltage data in a steady state. Apparent resistivity data were derived from the stacked voltage data, while IP data were initially extracted from these decay curves of these stacked voltage data and subsequently processed in the frequency domain (outphasing). Analysis of the resistivity and IP responses revealed notable IP signals at depths exceeding 1.5 km. Meanwhile, the resistivity data indicated generally very high values, around 10,000 ohm-m, with complex variations observed near the surface. This study demonstrates the efficacy of ERT and IP methods in delineating deep-seated mineral deposits, with the deep-depths IP responses being particularly noteworthy.

How to cite: Kim, B., Deparis, J., Darnet, M., Bretaudeau, F., Vedrine, S., Gance, J., Kamm, J., Autio, U., Patzer, C., and Heinonen, S.: Measuring Induced Polarization signals from deep seated magma chamber – preliminary results from a pilot survey in Finland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21924, https://doi.org/10.5194/egusphere-egu24-21924, 2024.

The Heath Discover – Advanced Mobile Leak Detection (AMLD) is an ultra-sensitive advanced technology capable of detecting natural gas leaks or emissions from a remote distance while driving on a street or right of way. It allows the user to cover large areas for compliance or emission surveys and provides reports and GIS data with breadcrumb trail on a Windows-based tablet app.

The Discover AMLD employs a mid-IR open path version of the proven TDLAS technology which has been used in other Heath Products such as RMLD-CS. It uses two Mid-Infrared Lasers, one each for Methane and Ethane, that pass through the air in front of the vehicle. As the lasers pass through a gas plume, the methane and ethane absorb a portion of the light, which the instrument detects. Based on the local meteorological conditions, a given amount of gas escaping from the ground will produce a plume that varies in size and uniformity of concentration levels. The plume, by nature is variable and dependent on the soil type, moisture, temperature, wind, venting and leak rate.

The Discover AMLD technology is already employed at 4 major gas utilities 2 domestic and 2 international and is being used to find real world leaks and disaster-based surveys. It is helping to distinguish between sewer/Biogas leak and pipeline leaks and is able to localize and quantify the methane emissions. The technology was demonstrated in real world conditions at more than 50 domestic and international gas utilities with excellent results. METEC facility at Colorado State University has done extensive testing and confirmed the efficacy and accuracy of the technology in its ability to find, localize & quantify emissions. This is helping utilities rapidly find leaks and reduce methane emissions to keep communities safe and reduce greenhouse gas emissions.

The technology was developed and commercialized by Heath Products division by connecting with research scientists at Physical Sciences Incorporation a premier research organization based in Massachusetts and utilizing their most innovative ideas and bring them to life. By using their TDLAS technology and adopting it to an open path vehicle mountable system that can be very versatile and completely wireless without the need to modify the vehicle, Heath engineers and technicians were able make it into a manufacturable product and make it available commercially in the last quarter of 2022. Since then, the product has been demonstrated and has impressed the technology evaluation laboratories of gas utilities and academia with its real-world prowess in rapidly discovering methane emissions and improving productivity of surveys by a multiplier of 4 or more. We believe that this will be a game changing technology that will help utilities in making their operations safer, build trust with communities and make environmentally friendly energy available to hundreds of millions of people.

How to cite: Wehnert, P. and Six, E.: Discover Advanced Mobile Leak Detection (AMLD) - Natural Gas Leak Surveys Utilitzing Mid-IR Open Path TDLAS , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1698, https://doi.org/10.5194/egusphere-egu24-1698, 2024.

EGU24-2391 | PICO | ERE1.11

Using Quantum Gas Lidar for Continuous Methane Emissions Quantification of Gas to Grid Plants in Water Sewage Treatment Works. 

Aaron Van Pelt, Bharanitharan Srinamasivayam, Alex Harrison, Doug Millington-Smith, and Gavin Lindsay

The recent global focus on anthropogenic methane emissions mitigation has accelerated the development and deployment of novel technologies to detect, quantify, locate and prioritize mitigation of fugitive and process emissions of methane, particularly within the oil and gas supply chain. The majority of emissions within this infrastructure result from large and intermittent sources. One study1 showed that the largest 5% of emissions (i.e. super emitters) typically contribute over 50% of the total emission volumeand another study2 found that most sources (66%) are intermittent, and account for most (48%) of the emissions. The largest impact on emissions mitigation therefore can be realized by deploying detection methods and technologies that are matched to how these two classes of emissions manifest in the infrastructure. Continuous monitoring solutions that can image and pinpoint emission sources are especially well-suited for use at sites that are expected to have intermittent process emissions.

We present recent work utilizing novel Quantum Gas Lidar for continuous methane emissions monitoring in sludge treatment works where methane-rich biogas is produced from the anaerobic digestion of sewage sludge. Some of the biogas is consumed on site and the rest is cleaned, upgraded and fed into the natural gas distribution network. Monitoring campaigns are ongoing at three such plants in the UK, owned and operated by Severn Trent, two of which have full gas to grid infrastructure. The third site uses combined heat and power engines to convert the biogas into electricity for use on site. Specific elements of the infrastructure are targeted for continuous, automated measurement by the lidar system (especially the digesters, gas storage, combined heat and power engines and gas to grid plants) and any detected methane emission plumes are imaged, their origins are pinpointed, and their emission rates are quantified. This results in a methane emission rate dataset having both high spatial and temporal resolution which can be used for both component and site-level emissions reporting within, for example, the OGMP 2.0 level 4 and level 5 framework, and IPCC Tier 3 (facility level) reporting. 3 The individual emission sources are intermittent and can have emission rates that vary in time depending on various process variables (i.e. varying pressures within the equipment) so that an accurate accounting of the overall emissions over time is reliant on the high-accuracy quantification and high temporal resolution that the lidar system provides. The continuous measurements have so far identified some previously unknown emission sources and have allowed the actual emissions of those sources to be accurately quantified for the first time, offering a high-confidence, measurement-based accounting of the methane emissions at these sites.

[1] https://pubs.acs.org/doi/10.1021/acs.est.6b04303

[2] https://pubs.acs.org/doi/10.1021/acs.estlett.1c00173

[3] https://www.ipcc.ch/report/2019-refinement-to-the-2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/

How to cite: Van Pelt, A., Srinamasivayam, B., Harrison, A., Millington-Smith, D., and Lindsay, G.: Using Quantum Gas Lidar for Continuous Methane Emissions Quantification of Gas to Grid Plants in Water Sewage Treatment Works., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2391, https://doi.org/10.5194/egusphere-egu24-2391, 2024.

EGU24-4195 | ECS | PICO | ERE1.11

A Two-dimensional Model for the Gas Transport in the Unsaturated Zone with the Soil Aeration 

Jui-Hsiang Lo, Kathleen Smits, and Daniel Zimmerle

To develop methods based on integrating the two-phase (liquid and gas) flow and free flow in the porous media to optimize the operation of subsurface gas venting, we developed a two-dimension soil aeration model based on the coupling of two-phase flow (liquid and gas) in the porous media with the single-phase flow (methane, CH4) in the free-flow domain under homogeneous, isotropic, and isothermal conditions. The dissolution, bioreaction, and thermal diffusion of CH4 are not included in the model. Numerical experiments were conducted with diverse near-surface meteorological conditions, soil properties (e.g., porosity, soil layering, air permeability, and soil moisture), and the deployment of venting bar holes to study the effects of environmental conditions and venting system designs on the gas flow in the subsurface. Simulation results not only demonstrated the capability of the soil aeration model on the prediction of the migration of the residual CH4 concentration in the subsurface due to the venting but also highlighted the influence of soil permeability, deployment of venting bar holes, and the venting pressure on the change in residual gas concentration in the unsaturated zone. During the soil aeration, the low soil permeability impacted the migration of advective air flow by venting in the soil and prolonged the operation time of the soil aeration. Furthermore, the Peclet number of the gas migration significantly decreased from the center of the venting bar hole with the decrease in soil permeability and venting pressure. The variation of venting pressure is more sensitive to the development of venting flow rates than that of the number of venting bar holes. The proposed 2D soil aeration model and approaches of evaluation of soil aeration in this study provide insights to investigate the multiphase flow in the subsurface due to soil aeration operation under various environmental conditions and venting strategies.

How to cite: Lo, J.-H., Smits, K., and Zimmerle, D.: A Two-dimensional Model for the Gas Transport in the Unsaturated Zone with the Soil Aeration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4195, https://doi.org/10.5194/egusphere-egu24-4195, 2024.

EGU24-4598 | PICO | ERE1.11

Unraveling Natural Gas Migration Rate and Extent from Leaking Underground Pipelines under Varying Environmental Conditions 

Kathleen Smits, Navodi Jayarathne, Daniel Zimmerle, Stuart Riddick, and Richard Kolodziej

Natural gas (NG) leakage from belowground pipelines is currently poorly understood, even though it is an area of safety, environmental, and economic concern. To date, there are limited studies on the transient behavior of NG, defined as the speed and maximum extent that gas travels belowground, and how this behavior changes with soil, environmental and leak characteristics. What is least identified is the interrelation between each controlling parameter, how to properly parameterize and characterize as well as the proper field application, specifically operator and first responder protocols. To address this gap, this work identifies key parameters influencing the transient behavior of leaked NG in the subsurface and opportunities to link this understanding to operator practice.  Though a three-year long series of over 150 controlled release experiments conducted at Colorado State University’s Methane Emission Technology Evaluation Center (METEC) and parallel numerical modeling we’ve investigated subsurface methane migration rates and extents and subsequent emission to the atmosphere. Experimental results were used to understand overall transient behavior both during and after terminating the leak. Numerical simulations were then used to extend experimental results to other conditions (e.g. additional soil types, surface conditions, and belowground infrastructure). Results demonstrate the impact of temporary rain and snow surface conditions on the extent and duration of leak transport, resulting in levels that pose heightened environmental and safety risks.  Furthermore, after leak termination, our findings demonstrate the isolated changes in the belowground migration time and the extent of leaked gas, driven by changes in surface and atmospheric conditions, a key point not consistently included in risk assessments or environmental emission rate calculations. While efforts to study a wider range of environmental conditions is underway, the findings of this study provide crucial insight to on identifying and prioritizing emissions from the perspective of both safety and the environment. 

How to cite: Smits, K., Jayarathne, N., Zimmerle, D., Riddick, S., and Kolodziej, R.: Unraveling Natural Gas Migration Rate and Extent from Leaking Underground Pipelines under Varying Environmental Conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4598, https://doi.org/10.5194/egusphere-egu24-4598, 2024.

EGU24-6658 | ECS | PICO | ERE1.11 | Highlight

A Comparison of the Effectiveness of Regulated OGI Leak Detection and Repair (LDAR) Surveys and Aerial Measurements in the Real-World 

Shona Wilde, David Tyner, Bradley Conrad, and Matthew Johnson

Periodic comprehensive or screening leak detection and repair (LDAR) surveys are a central part of many current regulations, which are intended to reduce unintentional methane emissions caused by leaking infrastructure.  In principle, by swiftly identifying and repairing leaks, emissions of methane, a potent greenhouse gas, are reduced.  The primary tools used for comprehensive LDAR surveys are Optical Gas Imaging (OGI) cameras.  While OGI can be effective for detecting and visualizing methane leaks, its extension to quantitative measurement (QOGI) is notoriously imprecise.  Moreover, studies have shown considerable variation in the performance of OGI in practice, where successful use is heavily dependent on the skill of the operator. 

Manual OGI surveys are also time consuming and labour intensive.  Implementing and maintaining an effective LDAR program that involves multiple OGI surveys per facility can be costly, potentially disrupting routine operations while requiring the deployment of trained personnel to each site.  Although operators are obligated to address and verify the repair of identified leaks, there is also still potential that significant leaks may be allowed to persist if they are not initially detected.  Consequently, despite the substantial costs involved, the full potential of methane reduction benefits may not be realized.  By contrast, aerial surveys have the potential to overcome many of the negatives associated with OGI surveys. In particular, aerial surveys can permit large numbers of sites to be surveyed per day at significantly lower cost per site, reducing overall compliance costs, labour requirements, and improving safety through reduced risks.  However, there remains no objective way to assess the relative performance of aerial surveys in complementing or replacing LDAR surveys under different scenarios.  In the context of emerging regulations, this is an especially important topic.

This work seeks to directly compare the effectiveness of conventional OGI surveys and aerial measurement under real-world conditions.  At an identical set of approximately 500 operating oil and gas sites in British Columbia, Canada, we compare and contrast detected and quantified sources in regulated LDAR surveys with parallel aerial surveys completed using Bridger Photonics’ Gas Mapping LiDAR (GML) technology.  The publicly reported LDAR reports are parsed to analyze patterns in detected emissions on 1 and 3 times per year deployments which are contrasted with aerial measurements at the same set of sites.  This direct contrast under real world conditions gives one of the first large scale tests of LDAR and aerial performance in practice, helping to provide quantitative guidance for the design of potential alternative LDAR programs under emerging regulatory scenarios.

How to cite: Wilde, S., Tyner, D., Conrad, B., and Johnson, M.: A Comparison of the Effectiveness of Regulated OGI Leak Detection and Repair (LDAR) Surveys and Aerial Measurements in the Real-World, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6658, https://doi.org/10.5194/egusphere-egu24-6658, 2024.

Establishing a streamlined workflow within the Monitoring, Measuring, Reporting, and Verifying (MMRV) framework is crucial for effective methane emission management and accurate methane emission reconciliation in the oil and gas (O&G) industry. Despite existing MMRV standards such as the Oil & Gas Methane Partnership 2.0 (OGMP 2.0), Veritas 2.0, and MIQ providing valuable guidance, the O&G industry still faces obstacles in compliance with these standards. These obstacles include (1) The Bottom-Up (BU) inventory, constructed with generic activity and emission factors, underestimates emissions and poses gaps in closing uncertainties during the reconciliation process, (2) The decision to deploy one or multiple methane sensing technologies, relying on emission profiles derived from limited sample measurements, can not accurately represent all emissions due to their inherent limitations and the stochasticity and intermittency of emissions, (3) No standard has been employed to assimilate observations from sensing technologies with varying measurement scales and data from operational events, and (4) Addressing various uncertainties, including those arising from direct measurements, atmospheric inversion modeling, and population inference from sample emission events, proves challenging in the final stages of the reconciliation process.

In this study, we present a streamlined MMRV-focused workflow integrating established and novel methodologies for reconciling emissions. The workflow consists of five key steps: Firstly, using the Oil and Gas Production Greenhouse Gas Emissions Estimator (OPGEE) to construct more accurate BU inventories and emission profiles for each type of equipment; secondly, determining the technology deployment plan and work practice based on constructed emission profiles using the Leak Detection and Repair Simulator (LDAR-Sim); thirdly, assimilating real measurements from deployed technologies through an ISO/OGC standard-based integrated sensor web architecture; fourthly, leveraging assimilated measurements and operational data to resolve emission events and reconcile the emissions; and finally estimating uncertainties from emission quantifications, inaccuracies in establishing emission event duration, and missed emission events. We demonstrate this workflow using data from the upstream O&G sites provided by an anonymous company. At the end of the demonstration we reconcile and report emissions by following the OGMP 2.0 guidelines. 

How to cite: Gao, M. and Liang, S.: Toward developing a streamlined workflow for methane emission monitoring, reporting, and verification in the oil and gas industry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7156, https://doi.org/10.5194/egusphere-egu24-7156, 2024.

The goal of reducing anthropogenic methane emissions, in particular those arising from oil and gas operations, will require the implementation of routine and effective monitoring, both to detect repairable emissions and to reliably report emitted quantities. This will mean a transition from research investigations to more formal requirements for monitoring which will be the responsibility of industry. Methane emissions are particularly challenging to measure as the sources are highly inhomogeneous in terms of the ranges of their emission characteristics such as emission rate, temporal behaviour, and the wide variety of potential sources of emissions (ducted emissions, vents, fugitive leaks from components, storage tanks, flares, onshore and offshore facilities). To enable baselining and reliable reporting from across different parts of the oil and gas industry, and to address the different needs from detection to quantification, a range of different methods based on different measurement technologies are needed. This has resulted in a large number of available and developing approaches. Industry will need confidence in the emissions data they report as they will be used to guide emission reduction activities and to report into international frameworks such as the IMEO. In future there will be increasing regulatory pressure.   
To support these growing requirements, and to support the selection of appropriate methods, there is therefore a need for a metrology framework to ensure the quality, reliability, comparability and suitability of measurement methods. It is important that the measurement uncertainties associated with methods are well understood including key sources of uncertainties, and the impact of the use of methods in different conditions and locations. This will not only support the selection of appropriate methods, but also enable the interpretation and comparison of data between sources and over different scales (both temporal and spatial).
This talk will outline these issues, review the requirements for defining clear measurement objectives and performance requirements and provide an illustration of what such a metrology quality framework would look like.  The talk will discuss the issues around determining the uncertainties in methane emission measurements and in particular in derived data such as emission rates, and the use of validation studies and controlled releases will be discussed. It will also provide an overview of current activities to develop standardised methods for monitoring methane emissions and to develop the tools to support the evaluation of such methods.

How to cite: Robinson, R., Innocenti, F., and Helmore, J.: The requirements for standardisation and performance evaluation for methane emissions monitoring technologies – a metrology perspective., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10605, https://doi.org/10.5194/egusphere-egu24-10605, 2024.

EGU24-13335 | PICO | ERE1.11

Aerial Gas Mapping LiDAR for Methane Emissions Management at Oil and Gas Infrastructure 

Michael Thorpe, Aaron Kreitinger, Peter Roos, Jason Brasseur, Benjamin Losby, Nathan Greenfield, Asa Carre-Burritt, William Kunkel, Dominic Altamura, Cameron Dudiak, Christopher Donahue, and Ben Moscona

We present an overview of aerial Gas Mapping LiDAR (GML) technology and its application to methane emissions monitoring and informatics for oil and gas infrastructure. The GML sensor combines spatially scanned and coaligned topographic and path-integrated methane concentration LiDAR measurements with navigation data and aerial photography to provide episodic detection, localization, emission rate quantification, and emission source attribution of methane plumes within scanned infrastructure. Aerial deployment enables rapid and efficient coverage of large and dispersed infrastructure. High sensitivity LiDAR measurements allow detection of methane emissions at rates below 1.5 kg/h with greater than 90% probability of detection in most deployment conditions, resulting in the detection of more than 90% of emissions from typical oil and gas production basins. The high spatial resolution of the LiDAR scans provides geo-location of emission sources, typically to within 2 m, for targeted LDAR response and reliable emission source attribution. Well characterized emission rate estimates, produced by combining LiDAR methane concentration measurements with gas flow speed information, allow source-level prioritization of LDAR response and enable accurate source-resolved methane emissions inventories.  Real-world examples of Gas Mapping LiDAR use cases will be presented and requirements for producing large-scale methane emission inventories including sample planning, facility and equipment identification, emission rate quantification accuracy, detection sensitivity, and statistical analysis methods will be covered. Specific applications of the GML technology include leak detection and repair (LDAR); measurement, monitoring, reporting, and verification (MMRV) programs; measurement-based methane emissions inventory and intensity benchmarking and reductions tracking; and differentiated gas certification programs. © 2024 The Author(s)

How to cite: Thorpe, M., Kreitinger, A., Roos, P., Brasseur, J., Losby, B., Greenfield, N., Carre-Burritt, A., Kunkel, W., Altamura, D., Dudiak, C., Donahue, C., and Moscona, B.: Aerial Gas Mapping LiDAR for Methane Emissions Management at Oil and Gas Infrastructure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13335, https://doi.org/10.5194/egusphere-egu24-13335, 2024.

EGU24-14031 | ECS | PICO | ERE1.11

Evaluation of a UAV-Based Methodology for Measuring Flare Combustion Efficiency 

Simon Festa-Bianchet, Milad Mohammadi, Alexis Tanner, Greg Kopp, and Matthew Johnson

This work will present a quantitative evaluation of the potential for measuring gas flare combustion efficiency using an aspirating sensor platform mounted under an uncrewed aerial vehicle (UAV).  The UAV sensor package contains lightweight commercial gas analyzers capable of precise measurements of atmospheric methane (CH4), ethane (C2H6), carbon dioxide (CO2), and carbon monoxide (CO).  By sampling the flare’s plume of combustion products with the help of a UAV, flare efficiency measurements can be safely and remotely completed without affecting the flare’s operation.  The relative mole fraction of the measured major carbon containing species can be used to close a carbon mass balance, which permits calculation of a local carbon conversion efficiency of the flare.  However, because the composition of the flare plume can be inhomogeneous as well as turbulent, it is not straightforward to determine whether the measured incomplete combustion products are representative of total inefficiencies.  Further uncertainty arises if the flared gas contains additional hydrocarbon species (e.g., C3+ hydrocarbons) that may not be directly measurable by the UAV platform.  To address these challenges, controlled experiments were completed on large scale (100-mm diameter) flares burning within Western University’s Boundary Layer Wind Tunnel.  With the wind tunnel running in an open circuit configuration, the UAV/sensor package was suspended within the wind tunnel test section downstream of the flare where it measured combustion efficiency while being moved in and out of the combustion plume.  Results were compared with known combustion efficiencies for identical operating conditions obtained following the established method of Burtt et al. (J. Energy Inst. 2022).  Further, combustion efficiency measurements from operating flares will be made using the developed sensor to validate the proposed measurement approach.  Ultimately, this tool could close a known gap in our ability to quantify carbon conversion efficiency and methane slip from flares under field conditions as required under emerging measurement, reporting, and verification (MRV) programs.  

How to cite: Festa-Bianchet, S., Mohammadi, M., Tanner, A., Kopp, G., and Johnson, M.: Evaluation of a UAV-Based Methodology for Measuring Flare Combustion Efficiency, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14031, https://doi.org/10.5194/egusphere-egu24-14031, 2024.

Recent emphasis on decreasing methane emissions from oil and gas production and transport has stimulated the development of multiple regulatory and voluntary reporting programs.  These programs include monitoring and verification requirements, commonly known as MMRV (methane monitoring, reporting and verification).  An underlying assumption in these programs is the use of advanced methods to estimate emissions, including continuously installed sensors at facilities and aerial, satellite and driving survey methods. These methods provide emission estimates at the scale of major sources or entire facilities. Regulatory programs in the USA and EU are increasingly tying these estimates to substantial financial risks while encouraging anonymous 3rd party measurements, raising the stakes for using these methods.  This abstract reviews recent studies of these methods, and reviews four areas of concern. 

First, multiple commonly used methods display accuracy problems which are likely to be present in most methods. Recent studies study assessed methods at production and midstream facilities onshore in the USA.  Two methods deployed simultaneously at 14 midstream facilities disagreed by 2:1 averaged across all facilities and by more than 2:1 at 6 of the facilities.  Other studies in U.S.A production and European midstream have identified similar accuracy issues. 

Second, ‘measurement informed inventory’ methods, which use full-facility estimates to update emissions reporting, remain poorly developed and unevenly implemented.  While one study found that survey methods identified large emitters and operators corrected reporting, another study found that most aerial detections did not result in effective corrections to inventory estimates. 

Third, methods used to extrapolate facility-scale estimates to basin scale have unaddressed uncertainties.  Recent work indicates that 9-49% of plumes detected by aircraft methods are due to maintenance emissions, which are poorly characterized by anonymous aerial sampling.  Additionally, extrapolation methods poorly estimate short emission events, resulting in a significant potential to over-estimate of emissions.  Conversely, random non-detects of exhaust emissions likely under-estimates emissions from engines and combustors by a factor of 2 or more.  These errors both shift emission between sectors and may result in significant bias. Additional control inputs, better GIS data, and improved methods are required to better estimate regional emissions.  

Finally, recent studies of continuous emissions monitors in both controlled and field tests indicate poor quantification accuracy in controlled testing, and poorer accuracy in field conditions. 

While advanced methods show promise for improving emissions detection and mitigation, consumers of these data need to be aware of the performance of these methods and account for bias, uncertainty, and variability of emissions estimates when constructing programs that utilize these estimates.

How to cite: Zimmerle, D.: Impact of Emissions Estimation Uncertainty on Methane Monitoring Reporting and Verification (MMRV) Programs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14035, https://doi.org/10.5194/egusphere-egu24-14035, 2024.

Satellite observations are an important tool in large emission event detection and global monitoring of methane emissions from oil and gas facilities, but current satellite-based methods face significant uncertainty. One of the major sources of uncertainty is a high rate of false positives. Current methods to mitigate false positive rates typically involve manual inspection of plume imagery, a time-consuming process which introduces human error. The Sentinel-2 multispectral satellite is widely used in global methane observation, as methane enhancements can be identified by a signal in shortwave infrared bands 11 and 12.  However, physical, biological and other anthropogenic processes can have a similar spectral signature, leading to a high rate of false positives. We present an empirical False Discovery Rate approach for quantifying the false positive probability for a given candidate plume. Imagery data is divided into a near-to-well set (within 200m of oil and gas infrastructure) and a far-from-well control set (between 400m-1200m away from oil and gas infrastructure), which is conservatively assumed to consist entirely of false positives. With these datasets, we define the probability of a false positive given proximity to oil and gas infrastructure as a function of plume quality and distance to infrastructure.  The results from this approach are shown for a case study over the contiguous United States, where we found a strong relationship between the selected plume quality metrics, distance to infrastructure and the false positive probability. We also identified significant differences in plume characteristics between the near-to-well and far-from-well datasets.  This work presents a more efficient and data-driven false positive algorithm, which can significantly reduce the manual step in false positive identification, resulting in larger scale deployment and data processing of satellite-based methane emission monitoring.

How to cite: Rischard, M., Schissel, C., and Niazi, M.: Methane leak or false positive? An automated probabilistic treatment of detected emissions from oil and gas facilities in multi-spectral satellite imagery at continental scale., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16519, https://doi.org/10.5194/egusphere-egu24-16519, 2024.

EGU24-20055 | PICO | ERE1.11

Transparent Horizons: IMEO's Methane Data Empowering Global Climate Action  

Daniel Zavala-Araiza, Steven P. Hamburg, Andreea Calcan, Stefan Schwietzke, James Lawrence France, Cynthia Randles, Marci Rose Baranski, Meghan Demeter, Roland Kupers, Robert Field, and Manfredi Caltagirone

Ambition on methane emissions reduction is growing, and open, reliable, measurement-based and actionable data is essential to track changes in emissions over time. The ability of countries and companies to meet their goals requires a thorough understanding of the magnitude and location of methane emissions, as well as being able to demonstrate progress towards these goals.  

As a core implementing partner of the Global Methane Pledge, the UN Environment Programme’s International Methane Emissions Observatory (IMEO) has been tasked with creating a sound scientific basis for methane emissions estimates and is providing reliable, public, policy-relevant data to facilitate actions to reduce methane emissions. IMEO is collecting and integrating diverse methane emissions data streams, including satellite remote sensing data, science studies, national inventories, and measurement-based industry reporting to establish a global, centralized public record of empirically verified methane emissions. 

Here, we will show the progress of IMEO towards developing its global, public dataset of policy-relevant methane data, highlighting successful mitigation case studies for the oil and gas industry from the pilot phase of IMEO’s Methane Alert and Response System (MARS), and from IMEO’s Methane Science Studies. We demonstrate how empirical data can drive real, tangible mitigation action in countries around the world.  

How to cite: Zavala-Araiza, D., Hamburg, S. P., Calcan, A., Schwietzke, S., France, J. L., Randles, C., Baranski, M. R., Demeter, M., Kupers, R., Field, R., and Caltagirone, M.: Transparent Horizons: IMEO's Methane Data Empowering Global Climate Action , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20055, https://doi.org/10.5194/egusphere-egu24-20055, 2024.

EGU24-20581 | ECS | PICO | ERE1.11 | Highlight

Combining Aerial and Ground Surveys to Quantify Oil and Gas Sector Methane Emissions in Colombia 

Nikolai Calderon-Cangrejo, Simon A. Festa-Bianchet, Bradley M. Conrad, David R. Tyner, Shona E. Wilde, and Matthew R. Johnson

Curbing methane emissions is a crucial aspect of achieving emissions reduction targets across the world. This is particularly important in Colombia, where it is estimated that 24% of anthropogenic methane emissions originate from the energy sector (IEA, 2023). However, the mitigation potential remains hampered by a lack of understanding of emission sources in the field and limited access to accurate official inventories.  The objective of this study is to develop a comprehensive inventory of methane emissions within the oil and gas industry in Colombia. The implemented framework consists of a hybrid inventory that integrates top-down, source-resolved aerial measurements with bottom-up measurements following the published methodology of Johnson et al., Comms. Earth & Environ, 2023. This approach not only facilitates a detailed attribution of emission sources but also quantifies the measurement and sample size uncertainties, employing the detection probability of the airborne sensor, Monte Carlo analysis, and bootstrap analysis.  For this study, around 3,400 facilities were included in the top-down campaign, complemented by a select sample of facilities in a parallel bottom-up campaign. The total facility sample covers six different production regions across five departments, including a wide range of oil and gas facilities and production types. This presentation will discuss the initial results of the field campaigns and progress towards the completion of a first-ever measurement-based methane inventory for Colombia that is intended to be used to support verified reporting under the International Oil and Gas Methane Partnership (OGMP 2.0).

How to cite: Calderon-Cangrejo, N., Festa-Bianchet, S. A., Conrad, B. M., Tyner, D. R., Wilde, S. E., and Johnson, M. R.: Combining Aerial and Ground Surveys to Quantify Oil and Gas Sector Methane Emissions in Colombia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20581, https://doi.org/10.5194/egusphere-egu24-20581, 2024.

Hundreds of thousands of unconventional natural gas wells recently constructed across North America have transformed the global energy landscape and generated widespread concern relating to fugitive methane leakage. To date, no studies have evaluated the integrity of unconventional wells post-abandonment. Here, we evaluated emissions at nine decommissioned unconventional wells within the Montney region of British Columbia, Canada and found two exhibited co-emission of CH4 and CO2 from surrounding soils indicating integrity failure, releasing up to ~2000 kg of CO2-eq/yr into the atmosphere. A further three wells exhibited statistically significant anomalous CO2 fluxes of ~500 kg/year from surficial soils around the well, likely associated with minor integrity failure and derived from near total soil-based aerobic oxidation of fugitive CH4. These findings suggest that more than half of decommissioned unconventional wells may generate emissions, however only relatively small contributions to GHG emissions result that are significantly mitigated through natural soils-based CH4 oxidation.

 

How to cite: Cahill, A.: Evaluating Methane Emissions From Decommissioned Unconventional Petroleum Wells in British Columbia, Canada, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22532, https://doi.org/10.5194/egusphere-egu24-22532, 2024.

EGU24-1444 | ECS | Posters on site | HS1.1.7

Urban green space: global assessment of potential energy demand reduction in buildings 

Giacomo Falchetta and Enrica De Cian

Climate change impacts are increasingly felt, and a key hazard for human health is exposure to chronic and acute heat. Air conditioning is an effective indoor adaptation technology. However, it is widely regarded as a form of “maladaptation” due to its high energy intensity and the detrimental impact it has on urban outdoor temperatures and global greenhouse gas emissions. On the other hand, urban green space (UGS) is widely regarded as an effective green infrastructure with potential to mitigate the urban heat island effect. In this context, here we built on a global validated model based on street-level vegetation density, satellite imagery, and ancillary covariates to track UGS in a large sample of cities worldwide (Falchetta and Hammad, forthcoming) and derive a context-aware but generalized statistical linkage with buildings electricity consumption statistics. Based on the modelled relations, we derive future projection of the potential contribution of UGS expansions to energy demand reduction in buildings in different regions of the world. Our study advances the quantitative, globally relevant understanding of the intersection between climate change adaptation and mitigation, and the role of nature-based solutions to reduce the feedback impacts of adaptation while providing ecosystem service co-benefits.

How to cite: Falchetta, G. and De Cian, E.: Urban green space: global assessment of potential energy demand reduction in buildings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1444, https://doi.org/10.5194/egusphere-egu24-1444, 2024.

EGU24-6337 | Posters on site | HS1.1.7 | Highlight

Simulating the impact of ground-based façade greenery design on indoor heat stress reduction 

Yannick Dahm, Karin Hoffmann, Oliver Schinke, and Thomas Nehls

Vertical greenery (VG) reduces the indoor heat hazard. To take advantage of their cooling effects, the underlying key design factors have to be understood. However, the influence of plant species, building type, and VG design on the thermal advantages has received limited attention in current literature.
Therefore, heat fluxes and temperature profiles for different ground based VG designs in the temperate climate of Berlin, Germany, were analysed using a process-based model. Indoor temperature profiles were integrated, assuming that air conditioning (AC) had been installed. Cooling effects have been simulated for six parameterised plant species of varying ages, across three different building types, and alternated air gap and crop thickness.
The results were compared, quantifying the cooling potential and the possible energy savings. They differ between plant species and building types. The diurnal variation of the indoor temperature resulted in maximum savings during the night. Fallopia baldschuanica showed the highest energy savings of approximately 23%. Thereby, it was multiple times more energy efficient than a Humulus lupulus.
This illustrates the significance of selecting the appropriate VG plant species. Considering factors such as growth rates and potential harm to buildings, VG can be strategically optimzed.

How to cite: Dahm, Y., Hoffmann, K., Schinke, O., and Nehls, T.: Simulating the impact of ground-based façade greenery design on indoor heat stress reduction, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6337, https://doi.org/10.5194/egusphere-egu24-6337, 2024.

EGU24-7729 | Posters on site | HS1.1.7

Evaluating Green Roof Heat Mitigation Potential in a Changing Climate 

Giovan Battista Cavadini and Lauren Cook

As the impacts of climate change intensify, bringing an increase in the frequency and magnitude of heat waves, the interest around urban heat mitigation strategies is rapidly growing worldwide. Green roofs, defined as roofing systems that incorporate a vegetated layer, have been proved to reduce urban heat, thanks to their evaporative cooling and lower heat storage than conventional roofs. Thus, they are expected to become increasingly important in the future, given their potential to counteract the projected temperature increases associated with climate change.

Numerous studies emphasize the urban heat mitigation potential of green roofs, yet accurate quantifications of their temperature reductions under future climate are currently lacking. For instance, under climate change, higher temperatures and longer dry periods are expected in central Europe, conditions that can negatively affect green roofs. Recently, microclimate models are gaining traction in evaluating the efficacy of heat mitigation strategies, facilitating the quantification of urban heat reductions under various climate conditions. However, despite their increasing use in the literature, microclimate models are rarely combined with climate projections, due to the complexity of downscaling interdependent weather variables such as precipitation, air temperature and global horizontal radiation. Consequently, the heat reduction potential of green roofs under future climates is largely unexplored, particularly in comparison to their observed performance under current climate. Additionally, it is unknown whether specific roof parameters could contribute to further enhancing heat mitigation, such as plant characteristics, irrigation schemes, or substrate depth.

This study aims to investigate the heat mitigation potential under climate change on a green roof in Mendrisio, Switzerland (characterized by hot, dry summers) using an open source microclimate model developed by Meili et al. (2020), Urban Tethys-Chloris (UT&C). This model was selected because of the fully coupled energy and water balance, and the incorporation of plant-specific characteristics. Continuous year-long monitoring of the green roof enabled to collect surface temperature using infrared sensors. These measurements were used to calibrate and validate the microclimate model. To account for climate change, coupled, sub-hourly, future projections of precipitation, air temperature, solar radiation, relative humidity, and wind speed were used as input to the validated microclimate model. These projections were derived from a convection resolving climate model (COSMO forced by MPI-M-MPI-ESM-LR at RCP 8.5, worst-case emissions scenario) run over the European domain at a 2.2-km, 6-minute resolution for a 10-year period that was bias corrected through quantile mapping. Lastly, variations in key parameters like substrate depth, vegetation type, and green roof irrigation schemes were explored to analyze their impact on urban heat mitigation under climate change.

Preliminary, manual calibration of the microclimate model resulted in a good predictive ability (r2 = 0.71), which will be further improved with automatic calibration. In a current climate, the green roof was able to reduce maximum surface temperatures in Summer by approximately 15°C, with respect to an adjacent concrete roof. Further expected results will evaluate potential temperatures reductions in a future climate and determine whether green roofs can counteract increasing temperatures by exploring a range of alternative designs.

How to cite: Cavadini, G. B. and Cook, L.: Evaluating Green Roof Heat Mitigation Potential in a Changing Climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7729, https://doi.org/10.5194/egusphere-egu24-7729, 2024.

EGU24-12889 | ECS | Posters on site | HS1.1.7 | Highlight

Rainfall temporal variability and rainwater harvesting efficiency: an analysis over the Italian territory.  

Matteo Carollo and Ilaria Butera

Rainwater harvesting for indoor uses could be a useful practice for a sustainable management of urban water. The realization of a rainwater harvesting system strictly depends on the costs and the required space so that an accurate design is necessary, especially in the tank sizing step. The volume of the tank is an important element of the system which impacts not only important environmental issues such as the volumes of saved potable water and the reduction of rainwater volumes to the sewerage system, but also the costs and the practical realization of the rainwater harvesting system. Nevertheless, while the professional world seeks solutions that are easy to apply (e.g. simplified sizing methods), from a scientific point of view several aspects are still to be clarified, among these the role of the temporal variability of rainfall in the tank sizing step, that is the object of the present study.

Rainfall temporal variability is quantified by the Coefficient of Variation (CV) of rainfall datasets. This analysis is carried out through numerical simulations and it is focused on the national Italian territory. Daily rainfall data of 3436 rainfall gauge stations located on the national Italian territory are considered and buildings with different catchment area and number of persons are taken into account. Our computations show that the majority of rainfall gauges in Italy has a rainfall CV in the 2.5-3.5 range, with higher values in the South and in the main islands. The role of the temporal variability of rainfall is clear: the same building in locations with the same mean annual rainfall depth, can require different tank sizes according to the rainfall coefficient of variation of the specific location. As an example, to reach the same water saving, a medium rise building located in Ascoli Satriano (CV=2.42) should be equipped with a tank size of 2700 litres, while in other locations which have the same mean annual rainfall depth but different CV, like Casale Monferrato (CV=3.41) and Muravera (CV=4.83), the required capacity is 3400 litres and 6800 litres, respectively. This underline the importance of taking into account the rainfall temporal variability in the tank sizing.

The analysis made use of non dimensional parameters, i.e. the storage fraction and the demand fraction, so that the results, obtained from different buildings over the Italian territory, are comparable, allowing in this way to build a unique graph that contains all information: the water demand, the mean annual rainfall depth and the rainfall coefficient of variation, as well as the number of inhabitants and the roof area of the building.

How to cite: Carollo, M. and Butera, I.: Rainfall temporal variability and rainwater harvesting efficiency: an analysis over the Italian territory. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12889, https://doi.org/10.5194/egusphere-egu24-12889, 2024.

EGU24-15912 | ECS | Posters on site | HS1.1.7

Modelling reference evapotranspiration of green walls (ET0vert) 

Karin A. Hoffmann, Rabea Saad, Björn Kluge, and Thomas Nehls

Green walls, facade greenery, living walls – vertical building greening as part of urban green infrastructure are measures for climate sensitive urban design, for water management and microclimate regulation. Strategic integration of green walls into local water and energy cycles requires prediction of evapotranspiration, considering the individual design, plant species, and building characteristics. Available models address horizontal surfaces but disregard vertical particularities and urban conditions, e.g., reduced direct radiation, spatial patterns of radiation on the wall due to building orientation and shading obstacles, and very heterogeneous wind fields that are influenced by rough surfaces, canyons, and adjacent wind barriers. We present a verticalization model, ET0vert, for the reference crop evapotranspiration ET0 (FAO) based on a sensitivity analysis. It comprises the adaptation of solar radiation and wind to the individual situations in front of a wall or facade. The accuracies of the model predictions are evaluated for (i) remote climate station data (horizontal reference plane), (ii) interpolated climate data (both horizontal and vertical reference plane) and (iii) on-site measured climate data (vertical reference plane, both not height-adapted and height-adapted) as input. We validate the model with data for a one-month reference period (25/07/2014 – 29/08/2014) from a weighable lysimeter with Fallopia baldschuanica greening of a 12 m high wall in Berlin, Germany.

Regarding individual meteorological input parameters, we found high relevance of both vapor pressure deficit (VPD) and solar radiation (RS) for the study area. Using VPD and RS, respectively, a linear model could explain 90 % and 85 % of daily ET0 variances. No such relationship could be detected for wind speed, but for maximum and minimum wind speed.

Compared to remote horizontal input data, verticalization of input data (RS and wind) reduced overestimations of ET from about 90 % to 14 % and 27 % for the daily and hourly resolution, respectively. If onsite climate data is available, deviations are reduced to 9 % and 5 % for the daily and hourly resolution. Height-adaptation of input data resulted in further improvements of the prediction accuracies (1 % and 2 % deviation for hourly and daily resolution).

We conclude that simply using remote horizontal climate data for calculating ET of green walls is not advisable. Instead, any input data, onsite measured or remote climate station data, should be verticalized and preferably height-adapted. The verticalized model predicts the hourly and daily evapotranspiration of green walls necessary for e.g., irrigation planning, building energy simulations or local climate modeling.

For more information: https://doi.org/10.5194/hess-2023-22

How to cite: Hoffmann, K. A., Saad, R., Kluge, B., and Nehls, T.: Modelling reference evapotranspiration of green walls (ET0vert), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15912, https://doi.org/10.5194/egusphere-egu24-15912, 2024.

EGU24-16430 | ECS | Posters on site | HS1.1.7

Assessing the microclimate conditions in urban green spaces and the effects of underlying driving factors in Switzerland 

Yuxin Yin, Gabriele Manoli, and Lauren Cook

Urbanization and climate change are leading to an increase in urban heat, posing a threat to human health and well-being. Urban green spaces (UGS), such as parks and gardens, have been recognized as an effective strategy for heat mitigation because they dissipate heat within their boundaries and in the surrounding areas. The magnitude of the cooling effect of UGS varies across locations and is affected by various factors, such as background climate, urban fabric, and vegetation properties. However, previous research studying the effect of UGS typically focused on specific case study areas and particular aspects of driving factors.

To do so, we integrate modeling, remote sensing datasets, and on-site measurements to assess the microclimate conditions of five different UGS (allotment gardens, public parks, private gardens, real estate yards, and ruderal sites.) in three Swiss cities with different biophysical conditions (Zurich, Geneva, and Lugano). Urban Tethys-Chloris (UT&C) model, a novel urban ecohydrological model with an explicit representation of urban canyon and vegetation properties, is applied to simulate the microclimate for each UGS and city. The models are validated using on-site measurements for air temperature, relative humidity, and surface temperature from July to October 2023. Preliminary results for Zurich show a good fit between simulation results and on-site measurements for both three variables, especially for air temperature and surface temperature with both R-squares larger than 0.8.

During the simulation period from June 21 to October 3, results will identify diurnal and daily patterns of microclimate conditions, including how different vegetation properties (i.e., height, canopy width, leaf area index, stomatal conductance) affect the microclimate. Subsequently, statistical regression will be employed to explore how the cooling effect of UGS is related to the distinct urban fabric and background conditions. Overall, the study will explain how various factors influence urban microclimate and provide insights on which factors will help to enhance the cooling effect in urban green space design.

How to cite: Yin, Y., Manoli, G., and Cook, L.: Assessing the microclimate conditions in urban green spaces and the effects of underlying driving factors in Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16430, https://doi.org/10.5194/egusphere-egu24-16430, 2024.

EGU24-17003 | Posters on site | HS1.1.7

Sustainable Water Consumption Strategies in a Changing Climate 

Christina Tsai, Yu-Kai Chiu, Ching-Hao Fu, and Yao-Wen Hsu

Water consumption is a fundamental global need.  Water production consumes lots of energy and emits plenty of greenhouse gases.  Determining the carbon footprint of water can offer various benefits. Reducing water use and conserving water can lead to lower energy consumption, lower carbon emissions, lower monthly water and energy costs, and less demand for water.  As carbon neutrality gradually prevails, low carbon emissions have become the future global trend and goal.  Therefore, it is crucial to understand the relationship between water consumption and carbon emissions.

As most countries struggle to reduce their carbon emissions in response to global warming, investments in water conservation, efficiency, and reuse are among the most cost-effective energy and carbon reduction strategies.  Urban water infrastructures have been demonstrated to contribute to global CO2 emissions significantly, and buildings account for a large portion of most urban water consumption.  Notably, while there is abundant rainfall in Taiwan, there appears to be a frequent water shortage crisis.  Such a crisis is aggravated by climate change because of the more unpredictable seasonal changes.  Climate change is linked to excessive anthropogenic carbon emissions. 

This study focuses on five types of buildings with various missions and usage on the National Taiwan University campus.  These infrastructures are typically deemed as having significant water consumption at National Taiwan University: (1) Residential buildings, (2) Experimental buildings, (3) Experimental farms, (4) the Department of Animal Science and (5) Lecture halls.  The specific objectives of this project are to uncover the nexus between thermal comfort and water consumption and the relationship between water consumption and hydro-meteorological and anthropogenic factors.

 

How to cite: Tsai, C., Chiu, Y.-K., Fu, C.-H., and Hsu, Y.-W.: Sustainable Water Consumption Strategies in a Changing Climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17003, https://doi.org/10.5194/egusphere-egu24-17003, 2024.

EGU24-391 | ECS | PICO | HS7.3

Explaining agricultural land use changes in Spain (2004 – 2021): Markets, climate and water resources. 

Gabriel Arbonès Domingo, Lucia De Stefano, and Alberto Garrido

In Spain, from 2004 to 2021, irrigation has increased by 500,000 hectares, the percentage of cultivated land with irrigation has increased from 18% in 2004 to 23% in 2021. The literature points to intensive irrigated agriculture as one of the main causes of the destruction of biodiversity, the worsening of the quality of water bodies, changes in the rural economy, among others. The study analysis the dynamics of land use changes in Spain particularly in irrigated crops, from 2004 to 2021 at provincial level. It aims to understand and promote sustainable land use transitions by identifying factors influencing farmers' decisions in altering land use and crop surfaces. To this end, several public open-access databases were used to analyse, on one hand, the land use changes at a detailed level, and on the other hand, guided by the literature to examine the factors behind the observed land use change. Findings reveal agricultural intensification trends in Spain, marked by the abandonment of less productive croplands and the intensification of highly productive lands, through the implementation of irrigation. The intensification, driven by the introduction of irrigated woody crops, mostly olives, vineyards, and almonds, predominantly occurred in the water-constrained southern region of the country. This was achieved by overcoming water limitations through increased exploitation of groundwater, and the widespread adoption of drip irrigation technology. Additionally, market trends driving increased demand for these commodities and changes in the Common Agricultural Policy (CAP) have further contributed to their expansion. We explain why some provinces intensify, via more irrigated and intensive crops, and reduce cultivated land, whereas others intensify and expand the total cultivated land. The study suggests that agricultural land change is a complex dynamic process, resulting from a combination of policy impact, market incentives, mature technologies, available resources and changing climate.

How to cite: Arbonès Domingo, G., De Stefano, L., and Garrido, A.: Explaining agricultural land use changes in Spain (2004 – 2021): Markets, climate and water resources., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-391, https://doi.org/10.5194/egusphere-egu24-391, 2024.

EGU24-697 | ECS | PICO | HS7.3 | Highlight

Rainfall accumulation as a driver of higher Leptospirosis risk in northern South America 

Alejandro Builes-Jaramillo, Clara Susana Arias-Monsalve, Juliana Valencia, Carolina Florian, and Hernán D. Salas

Rainfall accumulation during wet seasons in Northern South America can be enhanced during La Niña ENSO phases.  Leptospirosis is a zoonotic waterborne disease that affects humans, domestic animals, and wildlife associated with occupational and recreational water activities, natural disasters, and socioeconomic conditions for which rainfall plays a key role in its transmission. We analyzed the incidence of leptospirosis, and relative risk of changes on the incidence of the disease due to rainfall accumulation in Northern Colombia during the period 2007-2021. The rainfall accumulation analysis was done for 7, 14 and 21 days based on the periods of incubation of the disease, biology of transmission, and thresholds of rainfall accumulation above the mean values. We found a statistically significant association between excess rainfall and leptospirosis at different lags for cities in Northern Colombia (Barranquilla, Santa Marta, Cartagena) and the levels of accumulated rainfall exceedance associated with leptospirosis were specific for each city. Our findings give insight into the association between leptospirosis and excess accumulated rainfall and provide climate services and local health authorities with tools to act on and prevent this important zoonotic disease.

How to cite: Builes-Jaramillo, A., Arias-Monsalve, C. S., Valencia, J., Florian, C., and Salas, H. D.: Rainfall accumulation as a driver of higher Leptospirosis risk in northern South America, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-697, https://doi.org/10.5194/egusphere-egu24-697, 2024.

Environmental protection is of global interest to earth’s inhabitants with increasing concerns related to climate change. Solid wastes constitute an undeniable source of environmental degradation and a possible disaster to human health. In Jos Metropolis, a number of arable lands double as waste dumpsites and are at risk of heavy metal pollution. Shallow groundwater used for domestic purposes and plants cultivated near these dumpsites are prone to contamination and the prolonged consumption of unsafe concentrations of heavy metals through edibles and/or water may trigger numerous biochemical alterations in the human body. Subsurface geophysical investigation using 2D electrical survey and the assessment of soil and water quality has been carried out in the arable land and at close geological proximity to a solid waste dumpsite located at Utan, Jos, Plateau State, Nigeria. This study focus on delineating the lateral extent and depth of leachate migration into the subsurface from the waste dumpsite. 2D resistivity survey was carried out along three traverse (A, B and C) using Wenner–Schlumberger configuration. Qualitative interpretation of the inverse resistivity models revealed low resistivity zones of < 44 Ωm to be regions of leachate accumulation. The extent of downward migration through the vertical stratigraphic interval exceeds 15.6 m trending laterally in the eastern direction of traverse A. The analysis of heavy metal determination for water samples was aided by the use of Atomic Absorption Spectrophotometer while the soil samples were analyzed using X-ray fluorescence (XRF) analytical method. The concentrations of Pb and Ni in the analyzed water samples were above the permissible limit for drinking water and concentration of heavy metals in soil samples varies significantly. This study revealed the concentration of heavy metals in soil and water samples in close geographical proximity to the waste dumpsite and the uncontrolled disposal of waste over time poses great threat to the environment and its inhabitants. Waste management practices have to be improved upon to mitigate pollution.

How to cite: Obasuyi, F. O., Oladimeji, A. M., and Yusuf, T. A.: Investigation of the lateral extent and depth of contamination using 2D electrical resistivity and the assessment of soil and water quality in the vicinity of a Waste Dumpsite in Utan Jos, Plateau State. Nigeria., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1287, https://doi.org/10.5194/egusphere-egu24-1287, 2024.

EGU24-2496 | PICO | HS7.3

Effect of intermittent drainage on the emission of two greenhouse gases (CO2 and CH4) from three paddies in South Korea 

Seunghun Hyun, Wonjae Hwang, Minseok Park, Youn-Joo An, Sunhee Hong, and Seung-Woo Jeong

In this field pot study, effect of irrigation practice (continuous flooding (CF) and intermittent drainage (ID) treatment) on greenhouse gas (GHGs, CO2 and CH4) emission was determined from three Korean paddies (BG, MG, and JS series), varying soil properties such as soil texture, labile carbon, and mineral types.  Emission of GHGs was evidently influenced by irrigation practices, to a different extent, depending on paddy’s redox response to flooding events.  The Eh decline upon flooding was slower in JS pot, where pore-water concentration of ferric and sulfate ions is the highest (~ up to 3-fold) among three paddies.  MG pot was 2- to 3-fold percolative than others and the Eh drop during flooding period was the smallest (remaining above -50 mV) among three pots.  By adopting ID, CH4 emission (t CO2-eq ha-1 yr-1) was reduced in a wide range by 5.6 for JS pot, 2.08 for BG pot, and 0.29 for MG pot relative to CF, whereas CO2 emissions (t CO2-eq ha-1 yr-1) was increased by 1.25 for JS pot, 1.07 for BG pot, and 0.48 for MG pot due to the enhanced carbon oxidation upon drainage.  Grain yield and aboveground biomass production from ID were no less than those from CF (p < 0.05).  Consequently, benefit of global warming potential (S GWP) by ID varied as in order of JS (37%) > BG (14%) > MG (~0 %) pots, and negligible effect observed for MG pot was due to the equivalent trade-off between CO2 and CH4. Our findings imply that that the efficacy of drainage on GHG mitigation depends on the redox response of paddies.

Keyword

Climate Change, Greenhouse gas, Paddy, Intermittent drainage

 

Acknowledgement

This research was in part supported by the Korea Environment Industry & Technology Institute (KEITI), funded by Korea Ministry of Environment (MOE) (No. 2022002450002 (RS-2022-KE002074)) and in part supported by Korea University Grant.

How to cite: Hyun, S., Hwang, W., Park, M., An, Y.-J., Hong, S., and Jeong, S.-W.: Effect of intermittent drainage on the emission of two greenhouse gases (CO2 and CH4) from three paddies in South Korea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2496, https://doi.org/10.5194/egusphere-egu24-2496, 2024.

Agricultural development in Kinmen region has long suffered from the absence of a corresponding management unit responsible for irrigation planning and infrastructure maintenance, resulting in the majority of local farmlands relying on natural rainfall for cultivation. Unfortunately, this method is highly susceptible to the impacts of climate change. To address this pressing issue, the government plans to utilize reclaimed water from domestic sources as a supplementary irrigation resource. Within this context, this study aims to devise an irrigation water allocation model to optimally harness the limited water resources.

In this study, we simulate the crop rotation of local sorghum and wheat, considering soil, crop, and historical meteorological data. We calculate the variations in crop yield under different irrigation schemes. Additionally, we use historical meteorological data from Kinmen to calculate various simulated climates, testing the benefits of this irrigation plan under more extreme weather conditions. In conclusion, guided by the simulation outcomes and considerations of factors like cost and government procurement prices, we undertake a comparative analysis of the economic benefits under various scenarios and irrigation plans. This analysis aims to pinpoint the optimal irrigation water allocation plan that can be feasibly implemented by local farmers.

For this study, we have chosen a 100-hectare demonstration area located in Jinsha Town, Kinmen, as our study area. We will utilize 750 tons of reclaimed water provided daily by the Ronghu Water Resources Recycling Center as the irrigation water source, and the government has already established six agricultural ponds in the area to store water. Following this, our study will proceed with the implementation of the irrigation water allocation plan in the designated demonstration area. Our ultimate aim is for this initiative to serve as a starting point, enabling the systematic expansion of the irrigation water allocation plan to other regions in Kinmen, thereby enhancing the overall irrigation quality.

Keywords: Irrigation Water Allocation Model; Reclaimed Water; Rotation Irrigation; Kinmen; Sorghum

How to cite: Su, Y., Yu, H.-L., and Chang, T.-J.: Agricultural Irrigation Water Allocation Planning and Economic Benefit Assessment – A Case Study of Kinmen County, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2737, https://doi.org/10.5194/egusphere-egu24-2737, 2024.

EGU24-3235 | ECS | PICO | HS7.3

Estimating the risk of crop yield loss due to changing regional air temperatures 

Poornima Unnikrishnan, Kumaraswamy Ponnambalam, and Keith Hipel

Agricultural produce’s yield can be heavily impacted by changes in the weather patterns. With the current global warming scenario, the extremes temperature anomalies are expected to occur more frequently, posing a significant threat to the crop yields. To better plan the agricultural practices and crop rotation, it would be highly beneficial to understand the impact of temperature anomalies on crop yields. Here in this study, we investigated the impact of changing air temperature extremes on the yields of strawberries in farms in California's Central Valley. By using a copula modeling framework, the study has identified the risks of crop yield loss associated with temperature extremes. Based on this analysis, various scenarios of crop yield loss have been identified, and the likelihood of encountering those scenarios based on changes in temperature extremes has been estimated. The results of this study can be immensely helpful in planning agricultural practices and implementing appropriate measures to mitigate the risks. With air temperature forecasts readily available from various sources, nature-based solutions can be effectively implemented to combat the negative effects of temperature extremes on crop yields.

How to cite: Unnikrishnan, P., Ponnambalam, K., and Hipel, K.: Estimating the risk of crop yield loss due to changing regional air temperatures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3235, https://doi.org/10.5194/egusphere-egu24-3235, 2024.

Vegetation restoration such as human-induced and natural growth has seen a significant increase over the past two decades. However, this surge has raised concerns regarding its potential impact on water resources and its consequential hindrance to local social and economic development. Policymakers are particularly focused on mitigating the negative hydrological effects of vegetation restoration. Nevertheless, the implications for water yields in the context of forest management types, such as planted and natural forests, remain unclear. In this study, we explored hydrological responses to forest expansion in both planted and natural forest watersheds, utilizing evapotranspiration data synthesized from 12 data products, forest management maps, and climate datasets. Our analysis, based on the Budyko framework, revealed that water yield reduction in arid watersheds with planted forests (PFs) exceeded that in watersheds with expanding natural forests (NFs). Interestingly, vegetation restoration, whether in PFs or NFs watersheds, could even lead to an increase in water yield. Attribution analysis highlighted ecological restoration, rather than climate conditions, as the primary contributor to the observed water yield decrease. In NFs watersheds, the decrease was primarily linked to underlying characteristics, while in PFs watersheds, changes in water yield sensitivity to the land surface played a crucial role. It is noteworthy that vegetation restoration in humid zones exhibited a negligible impact on water yield. Even in NFs watersheds where water yield decreased due to tree cover expansion in drylands, natural growth emerged as a viable option to mitigate local hydrological effects in arid zones.

How to cite: Yan, Y., Liu, Z., and Jaramillo, F.: The distinct hydrological responses to vegetation restoration between planted and natural forests watersheds, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3708, https://doi.org/10.5194/egusphere-egu24-3708, 2024.

The study focuses on assessing the impact of climate change on water balance components in the Upper Ghatprabha River Basin in India. The Soil Water Assessment Tool (SWAT) is utilized to simulate streamflow in the basin. Calibration and validation of SWAT are performed across multiple sites using the Sequential Uncertainty Fitting Algorithm (SUFI 2). Performance assessment relied on metrics such as the Nash-Sutcliffe efficiency (NSE) and coefficient of determination (R2). Future climate projections are based on an ensemble mean of 13 bias-corrected GCM models for the Shared Socioeconomic Pathways (SSP) scenarios SSP245 and SSP585. The simulation of future basin water balance components involves segmenting the entire timeframe into S1 (2015-2040), S2 (2041-2070), and S3 (2071-2100). Projections indicate an increase in maximum and minimum temperatures, with precipitation potentially rising by up to 47% in the basin under the SSP245 scenario by the end of the century. Hydrological simulations reveal increased surface runoff and evapotranspiration under the SSP245 scenario compared to historical data. The percentage change in blue water components under both SSP scenarios shows an increase of more than 50% compared to the historical data. In comparison, that of green water components only increases to a maximum of 8% in all the timeframes (S1, S2 and S3). Notably, the impact of climate change is more pronounced under the SSP585 scenario compared to SSP245. These changes significantly impact the water resources of the Upper Ghatprabha River Basin; necessitating focused attention on future planning and management strategies for water resources.

How to cite: Jain, S. and Jain, M. K.: Assessment of Blue and Green Water Availability in the Upper Ghatprabha River Basin under Climate Change Impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4988, https://doi.org/10.5194/egusphere-egu24-4988, 2024.

EGU24-5462 | ECS | PICO | HS7.3

Influencing factors of durum wheat productivity under current and future climatic conditions 

Malin Grosse-Heilmann, Elena Cristiano, Francesco Viola, and Roberto Deidda

Durum wheat is a critical staple crop in arid and semi-arid regions worldwide, that plays a significant role in local food security. Providing essential nutrients and a high protein content, it is widely used for the production of pasta and couscous. Various constraints and drivers affect durum wheat productivity, including biotic and abiotic stressors, agronomic practices, and CO2 concentrations. Their influence varies based on duration and intensity of the stressor, as well as the durum wheat growth phase in which they occur. Drought and heat were shown to act as primary yield limiting factors. Furthermore, the water footprint, a comprehensive measure for the volume of water associated with crop production, helps to analyse durum wheat cultivation from a water-food nexus perspective. Given that climate change is affecting the main influencing factors of durum wheat’s productivity and of its water footprint, such as precipitation, temperature, and atmospheric CO2 levels, its cultivation is expected to undergo alterations as well. In this context, we explore the present state of durum wheat productivity and the potential influence of changing climatic conditions on its future cultivation worldwide. The current state of research on future durum wheat production is characterised by contradictory results, compromising projections of significant declines due to heat and drought stress as well as strong increases in productivity as a consequence of the CO2-fertilisation effect, for the same or nearby locations. Understanding the complex interactions between climate change, durum wheat productivity and the associated water footprint is of great importance to derive sustainable adaptation strategies and move one step closer into ensuring future food and water security.

How to cite: Grosse-Heilmann, M., Cristiano, E., Viola, F., and Deidda, R.: Influencing factors of durum wheat productivity under current and future climatic conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5462, https://doi.org/10.5194/egusphere-egu24-5462, 2024.

Mobile phones, televisions, computers and other liquid crystal devices have become the electronic products widely used by humans in modern society. Liquid crystal monomers (LCMs) are the key material of liquid crystal display and considered as potential persistent, bioaccumulative, and toxic (PBT) substances in recent years, but there is a limited of information regarding their occurrence in human body. We used EPI suite software from USEPA to evaluate its physical and chemical properties, analyzed its concentration in serum and urine by GC-MS, and finally assessed its health risk to humans through the calculation of daily intake. In this paper, 15 LCMs were detected in serum and urine samples of the general population, with median concentrations ranging from 9.7 to 124.8 and 2.68 to 36.98 µg/L, respectively. The correlation of LCM in serum and urine suggests that they have potential common applications and similar sources. The results showed that the CLrenal of LCMs in the Northwest China population was 0.61, 7.79, 6.04, 4.81, 9.37, 4.85, 19.94, 10.64, 3.80, 7.44, 8.26, 15.39, 7.52, 10.17, 13.54 mL/kg/day for EBCN, BCBP, PBIPHCN, DFPrB, FPrCB, BEEB, BMBC, DFPCB, DFEEB, EPrCPB, EEPrTP, EDFPB, DFPrPrCB, EFPeT, TeFPrT, respectively. The daily intake for ∑LCMs in the adult of northwest China was 22.35 ng/kg bw/day, indicating a potential exposure risk to the general population. This study provides the first evidence for the presence of LCM in serum and urine in the daily population and finds a correlation between LCMs, but the differences in B/U ratio and renal clearance indicate the need for further investigation of its metabolism and clearance in the human body.

How to cite: Yang, K., Cheng, H., Quan, W., Gong, Y., and Ai, Y.: Human health risks estimations from Liquid crystal monomers(LCMs)in Northwest China : partitioning, clearance and exposure in paired human serum and urine, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7771, https://doi.org/10.5194/egusphere-egu24-7771, 2024.

EGU24-8378 | ECS | PICO | HS7.3

Optimizing irrigation practices for sustainable olive production in semi-arid areas: A comparative analysis of the efficiency of Subsurface and Surface drip irrigation systems  

Sara Ourrai, Bouchra Aithssaine, Abdelhakim Amazirh, Salah Er-raki, Lhoussaine Bouchaou, Frederic Jacob, Mohamed Hakim Kharrou, and Abdelghani Chehbouni

Abstract : Irrigated olive trees constitute the main arboricultural component of orchards in semi-arid regions, and the optimization of irrigation practices is crucial to sustain the production, increase agricultural water productivity and reallocate water savings to other higher-value uses. Numerous technical strategies have been implemented in the last two decades, to promote water conservation in irrigated agriculture, namely the adoption of subsurface drip irrigation system. This study delves into a comprehensive comparative analysis between subsurface (SDI) and surface (DI) drip irrigation systems over an olive orchard, with an emphasis on the evolution of evaporative fraction (EF) and the ratio of transpiration (T) to evapotranspiration (ET), soil moisture distribution patterns, as well as water use efficiency and water productivity. The experiment was carried out over two irrigated olive plots located in the Tensift basin (Morocco), from May to October 2022. Each plot is subjected to a specific irrigation pattern, and equipped with an Eddy-Covariance system to quantify the energy balance components, along with Time-Domain-Reflectometry (TDR) sensors installed at various depths, to monitor the soil water content. Besides, the partitioning of ET into T and evaporation (E) over the two irrigation systems was performed using the Conditional Eddy-Covariance (CEC) scheme and validated using sap flow measurements collected over SDI plot during April 2023. The ET of the DI system was higher than that of the SDI one, with diurnal ET values ranging between 0.58-3.02 (mm/day) and 0.48-2.74 (mm/day) for DI and SDI systems, respectively. Our findings suggest that although a smaller irrigation water amount was applied in SDI (194 mm) compared to DI (320 mm), crop yield revealed no significant differences. This thorough assessment intends to add substantial knowledge to the lasting debate about sustainable irrigation practices over olive orchards and assist policymakers in making informed decisions to enhance water use efficiency while sustaining overall agricultural production.

Keywords: subsurface and surface drip irrigation; evapotranspiration; water productivity; water use efficiency; olive trees; semi-arid areas.

How to cite: Ourrai, S., Aithssaine, B., Amazirh, A., Er-raki, S., Bouchaou, L., Jacob, F., Kharrou, M. H., and Chehbouni, A.: Optimizing irrigation practices for sustainable olive production in semi-arid areas: A comparative analysis of the efficiency of Subsurface and Surface drip irrigation systems , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8378, https://doi.org/10.5194/egusphere-egu24-8378, 2024.

EGU24-8539 | ECS | PICO | HS7.3

Design of a low-cost autonomous seawater measurement buoy to scale and optimize a green-powered desalination plant 

Zachary Williams, Manuel Soto Calvo, and Han Soo Lee

Climate change and water scarcity has pushed more countries with direct ocean access to seek desalination solutions to face part of their need for domestic water networks or industrial usage, while conserving coastal ecosystems. Seawater monitoring is crucial in implementing a desalination plant as it ensures the efficiency and sustainability of the desalination process, especially in the case of a plant powered by renewable energy sources. Seawater is the main input of desalination processes and coastal areas are the locations of the release of the salty waste. An autonomous buoy can be used to monitor the seawater parameters which are essential to sizing a desalination plant.

There have been recent developments of autonomous buoy systems for monitoring different water parameters, however lacking in certain aspects. Some of the elements of these buoys include limited range of data transmission, high-cost designs, immobility and limited number and types of sensors. Also, there has been lacking implementation of autonomous buoys used in development of desalination plants. 

The proposed low-cost autonomous buoy is designed and constructed using cost effective materials. It increases the possibility of multiplying the sensor count to have a more accurate data mapping system. The low cost provides the opportunity of having more devices where there is a higher probability of equipment loss due to possible theft or remoteness of travel. The power supply is an oversized solar array with a backup battery and solar charger. An Arduino microcontroller is connected to two probes and a GPS sensor. The data is logged on a SD memory card with data transmitted via the Iridium satellite constellation, consisting of 75 satellites. There are two parts of construction involved in the project: the construction of the outer shell of the buoy and the design of the inner circuitry and components. The project involves multiple steps of experimentation: first in a laboratory/controlled area then deployed in the Seto Inland Sea, Japan. The various steps ensure the data collected by the sensors is reliable, valid, and suitable for scientific research. After this successful implementation, the buoy will be adapted and deployed in the Caribbean Sea surrounding Jamaica.

Initial results show a promising possibility of measuring seawater parameters such as GPS location, salinity, and sea surface temperature for any body of water. Utilizing the span of the Iridium satellite communication system, this ensures that virtually all regions of the Earth can be measured. The sizing of the solar powering components allows for at least 1 year of monitoring in the worst-case scenario and 4-5 years in the best-case scenario. The integration of autonomous buoys in the desalination process enhances efficiency in the plant design stages and reduces potential costs which contributes to the optimization of the desalination system. The environmental integration and the operation of the plant will be improved as a result of the enhanced assessment of the input and waste release conditions.

 

Keywords: Seawater Monitoring, Remote Sensing, Desalination, Autonomous buoy, Autonomous measurements

 

How to cite: Williams, Z., Soto Calvo, M., and Lee, H. S.: Design of a low-cost autonomous seawater measurement buoy to scale and optimize a green-powered desalination plant, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8539, https://doi.org/10.5194/egusphere-egu24-8539, 2024.

Reduced rainfall has been identified as a highly probable consequence of climate change in certain regions of Zambia. This is particularly concerning for small-holder farmers, who heavily rely on rainfall and are the primary producers of the country’s staple food, such as maize. The resulting decrease in production significantly impacts national food security. Recognizing the potential of irrigated agriculture to improve food security and sustain production levels, the Zambian Agricultural Research Institute (ZARI) has been actively engaged in research since 2021. Their focus is on enhancing irrigation and soil fertility management under conditions of reduced water availability.

To address these challenges, a research trial was initiated at the ZARI research station in 2021. This trial aims to identify the optimal and sustainable water and nitrogen application for achieving maximum maize production in irrigated crop systems. Access tubes were installed in each subplot to monitor soil moisture to a depth of 1 m before and after irrigation on a weekly basis.

This paper assesses the stored water in the root zone (up to 1 m) with interplay between amount of nitrogen fertilizer  applied and water application level.

In the 2021 season, the results indicate that significantly more water was retained averagely throughout the growing season  in treatments with higher nitrogen levels, especially under reduced irrigation water applications (50% and 75% ETc). A similar trend was observed in the 2022 season, albeit only for 50% ETc. The increased stover yield may have contributed to reduced evaporation, minimizing losses. As nitrogen application levels rise, the ability to store soil water in the profile appears to increase. However, further analyses of soil moisture depth and root systems are needed to determine whether excess water in deficit-irrigated treatments is obtained from lower depths or if (and how much) water is lost in optimally irrigated treatments.

How to cite: Mwape, M., Said Ahmed, H., Phiri, E., and Dercon, G.: Enhancing Maize Production in Irrigated Crop Systems: Optimizing Water and Nitrogen Application for Sustainable Agriculture in Zambia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8734, https://doi.org/10.5194/egusphere-egu24-8734, 2024.

EGU24-9386 | ECS | PICO | HS7.3

Food security in a changing climate - how can Earth observation and machine learning help?  

Emanuel Bueechi, Milan Fischer, Laura Crocetti, Miroslav Trnka, Ales Grlj, Luca Zappa, and Wouter Dorigo

Climate change is threatening food security. To ensure food security, we do not only have to safeguard agricultural production - crop yields also need to be optimally distributed. For that, decision-makers need reliable crop forecasts so that they can plan which regions are likely to experience crop yield losses and which regions will produce a surplus. Earth observation and machine learning are key tools to calculate such forecasts. However, extreme crop yield losses, for example caused by severe droughts, are often underestimated. To test this, we developed a machine learning-based crop yield anomaly forecasting system for the Pannonian Basin and examined its performance, with a focus on drought years. We trained the model (XGBoost) with crop yield data from 43 regions in southeastern Europe and predictors describing soil moisture, vegetation, and meteorological conditions. Maize and winter wheat yield anomalies were forecasted with different lead times (zero to three months) before the harvesting season. Our results show that the crop yield forecasts are significantly more reliable from 2 months before the harvest than before in both, drought and non-drought years. The models have their clear strength in forecasting interannual variabilities but struggle to forecast differences between regions within individual years. This is related to spatial autocorrelations and a lower spatial than temporal variability of crop yields. In years of severe droughts, the wheat yield losses remain underestimated, but the maize forecasts are fairly accurate. The feature importance analysis shows that in general wheat yield anomalies are controlled by temperature and maize by water availability during the last two months before harvest. In severe drought years, soil moisture is the most important predictor for the maize model and the seasonal temperature forecast becomes key for wheat forecasts two months before harvest. 

How to cite: Bueechi, E., Fischer, M., Crocetti, L., Trnka, M., Grlj, A., Zappa, L., and Dorigo, W.: Food security in a changing climate - how can Earth observation and machine learning help? , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9386, https://doi.org/10.5194/egusphere-egu24-9386, 2024.

EGU24-13506 | ECS | PICO | HS7.3

The impact of drought on the water-food nexus at the global scale 

Tobia Rinaldo, Elena Ridolfi, Benedetta Moccia, Flavia Marconi, Paolo D'Odorico, Fabio Russo, and Francesco Napolitano

The demand for farmland products is increasing worldwide, causing unprecedented stress on the global agricultural system and, consequently, on water resources. Here we analyse the impact of drought events on rainfed agriculture, a topical issue given the prolonged and severe drought events currently occurring around the world and thus including highly productive areas. We investigate the agricultural yields of key crops that represent 61% of the world’s production of proteins for human consumption (i.e. corn, wheat, rice, and soybeans). Our analysis spans from the early 1900s to 2022, allowing us to assess the total agricultural area under drought stress per year and the most vulnerable types of crops. We identify significant trends in the extent of agricultural land under stress, considering both historical and recent periods. This comprehensive analysis enables us to estimate the frequency of occurrences of crop-specific cultivated areas under stress over time, unravelling the pattern of drought impact on global agriculture.

How to cite: Rinaldo, T., Ridolfi, E., Moccia, B., Marconi, F., D'Odorico, P., Russo, F., and Napolitano, F.: The impact of drought on the water-food nexus at the global scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13506, https://doi.org/10.5194/egusphere-egu24-13506, 2024.

Continued population growth, changing climate and increased pressure on water resources will dramatically increase the pressure on Chinese agriculture in the coming decades. Although there have been some reports of yield stagnation in the world’s major cereal crops, including maize, rice and wheat, the reasons for stagnation have not been quantified thoroughly. Here, we use statistical data to examine the trends in crop yields for two key Chinese crops: maize and wheat and their drivers in China’s drylands. Results showed that although yields continue to increase in many areas, we found that across 70.2% of maize- and 51.9% of wheat- growing prefectures or provinces, yields either never improved, stagnated or collapsed. The reasons for the decline and stagnation of crop yield were mainly caused by the change of growing season precipitation and irrigation fraction. New investments such as increased irrigation fraction in underperforming regions, as well as strategies to continue increasing yields in the high-performing areas, are required.

How to cite: Zi, S.: Recent patterns of crop yield growth, stagnation and their drivers in China’s dryland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13868, https://doi.org/10.5194/egusphere-egu24-13868, 2024.

EGU24-18617 | ECS | PICO | HS7.3

Climate change impact on wheat yield in India: Study using CERES-wheat model 

Achanya Lakshmanan, Yogendra Shastri, and Riddhi Singh

Agriculture is highly dependent on climate because rainfall, temperature and sunlight are the primary determinants of crop development. Climate change driven effects such as variation in precipitation and changes in temperatures are likely to affect agricultural yields. Systematic planning of agricultural activities considering these effects is essential. As a first step towards this longer term objective, this work quantifies the effect of climate change on crop in short and long term in India. Wheat is chosen as the crop of interest. Madhya Pradesh, one of the leading wheat producing states in India, is the region under focus, and Betul district is selected for a initial studies. The CERES-wheat model in the Decision Support System for Agrotechnology Transfer (DSSAT) tool is used to estimate the impact of climate change on wheat yield. The CERES-wheat model has been calibrated and validated, and the calibrated parameters have been used to simulate wheat yield in the future. The base period for calculating base wheat yield is 2009-2019. Future wheat yields are calculated for two periods (2025-2055 and 2056-2085). The projected changes in precipitation, maximum temperature (Tmax) and minimum temperature (Tmin) in future compared to the base period are calculated using four different General Circulation Models (GCMs) and four Shared Socioeconomic Pathways (SSPs). To increase the study's robustness, 1000 samples are systematically generated using Latin Hypercube Sampling (LHS). A stochastic weather generator (WG), WeaGETS, is used to create a synthetic time series of climate variables. Using the 1000 different combinations of changes in climate variables, 1000 climate scenarios are generated using WeaGETS. The climate variables used to determine the relationship between climate and wheat yield were mean rainfall, rainfall variance, Tmax, and Tmin. Wheat yield ranged from 2065 to 3207 kg/ha during the baseline period, and it is expected to vary from 1629 to 3638 kg/ha between 2025 and 2055. Looking ahead to 2056-2085, wheat yields are estimated to range from 1363 to 3555 kg/ha. The sensitivity analysis results between climate variables and wheat yield for both periods suggest that wheat yield is positively correlated with mean rainfall and rainfall variance and negatively correlated with Tmax and Tmin. Maximum temperature has a significant negative correlation with wheat yield in both periods after excluding the effect of other climate variables. However, in the last stage of wheat yield development, the grain filling stage, Tmin is more critical than Tmax. These results highlight the need for systematic planning to manage negative impacts of climate change on wheat cultivation in India. These results will used as a basis for suggesting adaptation strategies to manage the impact of climate change on wheat yield.

How to cite: Lakshmanan, A., Shastri, Y., and Singh, R.: Climate change impact on wheat yield in India: Study using CERES-wheat model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18617, https://doi.org/10.5194/egusphere-egu24-18617, 2024.

EGU24-19902 | PICO | HS7.3

Estimating and Suggesting measures to reduce carbon emissions and water footprint linked to water collection, agriculture, and tourism in the Canary Islands (Spain) 

Juan C. Santamarta, Noelia Cruz-Pérez, Joselín R. Rodríguez-Alcántara, Jesica Rodríguez-Martín, Alejandro García-Gil, Samanta Gasco-Cavero, and MIguel Á. Marazuela

The Canary Islands constitute an archipelago of Spain, also being a European outermost region composed of eight islands. Overall, these islands face a high risk of experiencing the impacts of climate change, particularly rising sea levels, floods, temperature increases, and a decrease in water resources, factors that significantly affect the daily life of the population in the islands. As the effects of climate change are linked to greenhouse gas emissions, it is crucial to measure the emissions from the main sectors of the Canary Islands to implement effective mitigation and reduction measures, as well as to increase energy production through renewable sources. For this reason, the Government of the Canary Islands has commissioned the project to determine the carbon footprint and water footprint of the main sectors of the region, including the production of drinking water and wastewater management, agriculture, and tourism. The results indicate that seawater desalination for drinking water, being a significant energy consumer with low penetration of renewable energy in the Canary Islands' electricity mix, is the facility contributing the most to greenhouse gas generation in the water cycle in the region. It is followed by wastewater treatment plants and extraction wells from the aquifer. In the case of agriculture, focusing on the consumption of tropical crops such as avocados and bananas, key export crops, it is noteworthy that avocados are major water consumers, slightly exceeding the water consumption of bananas. This poses challenges in the face of an uncertain future due to reduced natural precipitation resulting from climate change. Lastly, the analysis of tourism emissions highlights that hotel activities and rental vehicles are significant contributors to greenhouse gas emissions. Although these emissions are indirect for the archipelago, other studies have emphasized the high emissions associated with the arrival of tourists by air to the islands. This study stands as the first to analyze the emissions of the main sectors in the Canary Islands, providing an opportunity for governmental actions to reduce these emissions and mitigate climate change in the islands.

Keywords: Climate change; outermost region; vulnerability; sustainable development

Acknowledgements

This research was supported by the European Union's Horizon 2020 Research and Innovation Programme under grant agreement 101037424 and Project ARSINOE (Climate Resilient Regions Through Systems Solutions and Innovations).

How to cite: Santamarta, J. C., Cruz-Pérez, N., Rodríguez-Alcántara, J. R., Rodríguez-Martín, J., García-Gil, A., Gasco-Cavero, S., and Marazuela, M. Á.: Estimating and Suggesting measures to reduce carbon emissions and water footprint linked to water collection, agriculture, and tourism in the Canary Islands (Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19902, https://doi.org/10.5194/egusphere-egu24-19902, 2024.

EGU24-20643 | PICO | HS7.3

The use of crop models to assess crop production and food security 

Yohanne Gavasso Rita, Simon Papalexiou, Yanping Li, Amin Elshorbagy, Zhenhua Li, and Corinne Schuster-Wallace

The global food supply and food security are altered by field, soil, and weather conditions during crop production. Researching food productivity became crucial as the global population increased. In particular, crop losses bring low food supply and price instabilities at the regional and global levels. With that in mind, we reviewed ten crop models and the most simulated impacts from soil-crop-atmosphere interactions in maize, rice, and wheat production. Since 2012, modellers have mainly used APSIM to predict water availability, temperature changes and Greenhouse Gas  (GHG) concentration to predict crop phenology, growth and development, grain filling and nutrient content, and yield. Since 2013, AquaCrop has been used to simulate scenarios focused on water balance in crop production systems, water stress and irrigation planning. Interestingly, Biome-BGCMuso was developed as a biogeochemical model and was not considered good by crop modellers. However, After updates, version v6.2 can simulate different management and field conditions for fifteen crops, considering heat, nitrogen and drought stress. Since 2008, crop modellers used CropSyst to evaluate water availability, nitrogen use efficiency (UE), temperature shifts and GHG concentration in rainfed and irrigated crop systems. Since 2002,  crop modellers have used DAISY to predict crop growth, nitrogen and water UE, grain content, yield gap, and losses. Since 2011, researchers have used DSSAT-CERES for mitigation strategy planning by predicting crop growth, soil characteristics, changes in land use, and nitrogen and water UE. Since 2015, JULES has been used to determine land-atmosphere interactions, changes in land use and GHG impacts on agriculture. Since 2008, ORYZA modellers have mainly predicted nitrogen and water UE, salinity impacts, and toxicity to rice. STICS was developed in 1996, and since 2008, it has been primarily used to simulate fertilization and irrigation systems, nitrogen leaching, and water availability. Since 2000, researchers have used WOFOST to analyze water availability, crop growth, and productivity under temperature changes. Crop models are fast and reliable resources when simulating crop production and food availability.

How to cite: Gavasso Rita, Y., Papalexiou, S., Li, Y., Elshorbagy, A., Li, Z., and Schuster-Wallace, C.: The use of crop models to assess crop production and food security, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20643, https://doi.org/10.5194/egusphere-egu24-20643, 2024.

EGU24-20876 | ECS | PICO | HS7.3

Application of Machine Learning Approaches for Cotton Seasonal Yield Estimation  

Lisa Umutoni, Vidya Samadi, Jose Payero, Bulent Koc, and Charles Privette

Estimating crop yield can help farmers plan for equipment, labor, and other crop production input requirements. Forecasting crop yield is also useful for analyzing weather-related variability to guide decisions such as irrigation water and fertilizer management. This work discusses the application of Gated Recurrent Unit (GRU) and Long Short-Term Memory (LSTM) machine learning algorithms for seasonal cotton yield prediction. Simulation results from the crop model AquaCrop, consisting of irrigation depth, soil moisture content, and crop growth stage data from 2003 to 2021 were used to train the algorithms. The two developed yield-prediction models were tested against data collected from an irrigated cotton field located at Clemson University Edisto Research and Education Centre (EREC), near Blackville, South Carolina, USA during the 2023 growing season. The values of hidden layers, hidden units, dropout, learning rate and batch size hyperparameters were set to respectively, 3, 64, 0.2, 10E-3 and 64 for the GRU model and 3, 128, 0.4, 10E-3 and 64 for the LSTM model. Analysis suggested that the tested algorithms resulted in very good to excellent performance. We concluded that machine learning algorithms are useful tools that can provide insights into how much yield to expect in an upcoming season and help farmers optimize energy, water, and fertilizers applications.

How to cite: Umutoni, L., Samadi, V., Payero, J., Koc, B., and Privette, C.: Application of Machine Learning Approaches for Cotton Seasonal Yield Estimation , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20876, https://doi.org/10.5194/egusphere-egu24-20876, 2024.

EGU24-21145 | ECS | PICO | HS7.3

Climate Risk and Vulnerability Assessment (CRVA) for the Port of Heraklion in Greece  

Anastasios Perdios, Antonios Boutatis, Andreas Langousis, Panagiotis Biniskos, Eva Kypraiou, Konstantina Korda, and Alexandros Zacharof

Climate change is expected to impact the maritime sector, including the port industry. Ports are on the frontline when it comes to experiencing operational challenges from the increased sea levels and extreme weather conditions, associated with increased infrastructure investments. For instance, rising sea water levels are expected to change the accessibility of channels and increase the need for higher quay walls, while the increased intensity or/and frequency of events, such as fog, high winds, and waves, may increase the frequency of port operation disruptions; but changes are uncertain, and with regional variation.

The present study focuses on the Port of Heraklion, one of the main ports of national importance in the Greek Maritime Network, located in the North side of the island of Crete, and aims at assessing the impacts of climate change on port operations associated with: 

  • Changes in mean sea level, storm surges and wave characteristics (i.e. wave height, period, frequency of occurrence).
  • Reduced visibility caused by intense precipitation and/or fog.
  • Disruption of port operations due to high wind speeds, drainage system induced flooding, as well as river discharges and sediment transfer in the harbor basin.

To assess the effects of climate change on winds we use climate change factors (CCFs) obtained using climate model data at 3-hourly temporal resolution over the Island of Crete (i.e. sub-country level) from EURO-CORDEX ensemble, and more in particular from HIRHAM5 RCM (Regional Climate Model) nested in (downscaled from) EC-EARTH GCM (Global Climate model), for two Representative Concentration Pathways of future emissions: RCP 4.5 for the period 2071-2100 and RCP 8.5 for the period 2041-2070. These are also the RCM-GCM combination and time periods used to assess the effects of climate change on the sea state and wave characteristics.

For rainfall, we make direct use of the climate change factors reported in the context of SWICCA program (Service for Water Indicators in Climate Change Adaption, 2015 - 2018), which was financed by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the European Copernicus Agency within the framework of the Copernicus climate change service (C3S). Over the island of Crete, the corresponding factors are available for 9 GCM - RCM combinations (i.e. 5 for the RCP 4.5 scenario and 4 for the RCP 8.5 scenario).

We find that the increase of the mean sea level, as well as the increase in the frequency of intense storms significantly affect the frequency of port operation disruptions, particularly due to breakwater overtopping, storm induced flooding, as well sediment deposition in the harbor basin.

Acknowledgements

The presented work has been conducted under the project Climate Risk and Vulnerability Assessment (CRVA) for the Heraklion Port Authority" (project code: AA 011391-002/CC15302), which has been financed by the EIB under the InvestEU Advisory Hub. 

How to cite: Perdios, A., Boutatis, A., Langousis, A., Biniskos, P., Kypraiou, E., Korda, K., and Zacharof, A.: Climate Risk and Vulnerability Assessment (CRVA) for the Port of Heraklion in Greece , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21145, https://doi.org/10.5194/egusphere-egu24-21145, 2024.

Because of their computational expense, models with comprehensive tropospheric chemistry have typically been run with prescribed sea surface temperatures (SSTs), which greatly limits the model’s ability to generate climate responses to atmospheric forcings. In the past few years, however, several fully coupled models with comprehensive tropospheric chemistry have been developed. For example, the Community Earth System Model version 2 with the Whole Atmosphere Community Climate Model version 6 as its atmospheric component (CESM2-WACCM6) has implemented fully interactive tropospheric chemistry with 231 chemical species as well as a fully coupled ocean. Earlier versions of this model used a “SOAG scheme” that prescribes bulk emission of a single gas-phase precursor to secondary organic aerosols (SOAs). In contrast, CESM2-WACCM6 simulates the chemistry of a comprehensive range of volatile organic compounds (VOCs) responsible for tropospheric aerosol formation. Such a model offers an opportunity to examine the full climate effects of comprehensive tropospheric chemistry. To examine these effects, 211-year preindustrial control simulations were performed using the following two configurations: (1) the standard CESM2-WACCM6 configuration with interactive chemistry over the whole atmosphere (WACtl) and (2) a simplified CESM2-WACCM6 configuration using a SOAG scheme in the troposphere and interactive chemistry in the middle atmosphere (MACtl). The middle-atmospheric chemistry is the same in all configurations, and only the tropospheric chemistry differs. Differences between WACtl and MACtl were analyzed for various fields. Regional differences in annual mean surface temperature range from −4 to 4 K. In the zonal average, there is widespread tropospheric cooling in the extratropics. Longwave forcers are shown to be unlikely drivers of this cooling, and possible shortwave forcers are explored. Evidence is presented that the climate response is primarily due to increased sulfate aerosols in the extratropical stratosphere and cloud feedbacks. As found in earlier studies, enhanced internal mixing with SOAs in WACtl causes widespread reductions of black carbon (BC) and primary organic matter (POM), which are not directly influenced by VOC chemistry. These BC and POM reductions might further contribute to cooling in the Northern Hemisphere. The extratropical tropospheric cooling results in dynamical changes, such as equatorward shifts of the midlatitude jets, which in turn drive extratropical changes in clouds and precipitation. In the tropical upper troposphere, cloud-driven increases in shortwave heating appear to weaken and expand the Hadley circulation, which in turn drives changes in tropical and subtropical precipitation. Some of the climate responses are quantitatively large enough in some regions to motivate future investigations of VOC chemistry’s possible influences on anthropogenic climate change. Additional simulations of a 2000 baseline (rather than preindustrial) climate reveal that these results are sensitive to the prescribed land emissions. Most of this work was recently published in Atmospheric Chemistry and Physics (doi:10.5194/acp-23-9191-2023).

How to cite: Stanton, N. A. and Tandon, N. F.: How does tropospheric VOC chemistry affect climate? Investigations using the Community Earth System Model Version 2., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2025, https://doi.org/10.5194/egusphere-egu24-2025, 2024.

EGU24-3142 | ECS | Posters on site | AS3.26

Understanding and quantifying chemical uncertainties in the hydrogen budget 

Rayne Holland, M. Anwar H. Khan, and Dudley Shallcross

The potential transition to a hydrogen-based economy, requires a comprehensive understanding of hydrogen's atmospheric behaviour for well-informed decision-making. Among the uncertainties surrounding the atmospheric fate of hydrogen, the chemical processes governing its formation and transformation are pressing.

This study employs STOCHEM-CRI, a global 3D tropospheric chemical transport model, to explore the chemical uncertainty associated with atmospheric hydrogen. The primary objective is to improve our understanding of the hydrogen distribution, sources, and sinks on a global scale. Addressing the significant role of formaldehyde (HCHO) as a chemical source, we update its photolysis parameterisation in accordance with recent recommendations (JPL 2020 and IUPAC 2013) and assess its variability. Furthermore, we evaluate the atmospheric burden of HCHO as a function of its sources to identify key photochemical contributors to the present hydrogen budget.

The study undertakes preliminary studies of the major sink of atmospheric hydrogen, namely uptake by soil, to gauge its impact. Through a meticulous examination of model outputs against observational data, various scenarios are systematically assessed for their ability to accurately replicate global hydrogen distribution and seasonal variations.

Preliminary results show updates to the photochemical parameters of HCHO significantly reduce the hydrogen burden by between 50 and 90 ppb globally. This is namely due to updates to the quantum yield of the molecular (H2 producing) photolysis channel which varies significantly when compared to previous recommendations. There is limited variation between the two updates (JPL 2020 and IUPAC 2013) of up to 5 ppb. Additionally, minor updates relating to the temperature dependence of the soil sink result in significant improvement in the models replication of observational data, including seasonal variation.

How to cite: Holland, R., Khan, M. A. H., and Shallcross, D.: Understanding and quantifying chemical uncertainties in the hydrogen budget, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3142, https://doi.org/10.5194/egusphere-egu24-3142, 2024.

EGU24-3552 | ECS | Posters on site | AS3.26

Hydrogen supply chain and its impacts on energy storage and carbon neutrality 

Tatsuto Yukihara and Qian Sun

As a clean and efficient secondary energy, hydrogen energy is of great significance for energy transition and carbon neutrality. However, hydrogen development faces big challenges of high cost, unclean in production process, insecurity in transportation and storage etc. This paper tries to build a theoretical framework of hydrogen supply chain which contains whole life cycle of production, transportation, storage, utilization, and recycle of end use. Our study shows that a complete and mature hydrogen energy supply chain can enlarge the scale of hydrogen production and reduce the cost, improve its efficient and safety, and obtain a stable, sustainable, and zero-emission energy system. At the same time, a sound hydrogen energy supply chain also plays an important role in ensuring energy security and a bridge for the transition from fossil energy to renewable energy and these will help to reduce CO2 emissions, promote carbon peaking and neutrality through energy technological innovation and rapid energy transition.

Key words: Hydrogen energy storage, hydrogen industry supply chain, green hydrogen, energy transition, carbon peaking and neutrality.

How to cite: Yukihara, T. and Sun, Q.: Hydrogen supply chain and its impacts on energy storage and carbon neutrality, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3552, https://doi.org/10.5194/egusphere-egu24-3552, 2024.

EGU24-4434 | ECS | Posters on site | AS3.26

Uncertainties in tropospheric ozone changes due to natural precursor emissions 

Xingpei Ye, Xiaolin Wang, Danyang Li, Paul Griffiths, Alex Archibald, and Lin Zhang

Accurate modelling of tropospheric ozone is crucial for understanding its climate and health effect, yet the uncertainty associated with natural ozone precursor emissions such as lightning and soil NOx is often overlooked. Here we apply a global chemical transport model, GEOS-Chem High Performance, to explore this uncertainty.

The modelled present-day tropospheric ozone burden, under low to high natural NOx emissions levels (set to align with the current literature’s range), varies from 285 to 373 Tg; primarily attributed to lightning NOx uncertainty. Such a range far exceeds the ozone difference driven by anthropogenic emissions between the two most disparate SSP scenarios in 2050 (33 Tg). Ozone’s sensitivity to natural emissions is the highest around the tropical upper troposphere where ozone’s climate effect is also large, and would be even higher if anthropogenic emissions were reduced along the SSP1-2.6 pathway. At the surface, global mean warm-season ozone ranges from 32.4 to 38.8 ppbv, mainly due to soil NOx. This especially introduces large ozone uncertainties in southern hemisphere regions such as the Amazon and Australia.

We also examine ΔO3-anthro, the ozone change driven by anthropogenic emissions changes up-to 2050. We found that with respect to tropospheric ozone burden, ΔO3-anthro shows limited differences between high and low natural emission levels (~13%), implying that the estimate of future changes in ozone radiative forcing is subject to less uncertainty from uncertain natural emissions than the present-day ozone radiative forcing itself. However, ΔO3-anthro related to the surface ozone exposure metric shows significant contrasts with different natural NOx emissions. The largest difference exceeds 5 ppbv (~50%) in regions such as Europe, North America, eastern China, and India. We hence stress that extra care needs to be taken when using individual models to assess ozone health risks in these densely populated regions as highly uncertain natural emissions will produce a presently unconstrained error.

How to cite: Ye, X., Wang, X., Li, D., Griffiths, P., Archibald, A., and Zhang, L.: Uncertainties in tropospheric ozone changes due to natural precursor emissions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4434, https://doi.org/10.5194/egusphere-egu24-4434, 2024.

EGU24-6038 | ECS | Posters virtual | AS3.26

A Simple Approach for Atmospheric Hydrogen Modelling Based on the Seasonal Variability 

Alexander Tardito Chaudhri and David Stevenson

Anthropogenic hydrogen emissions to the atmosphere have the potential to increase if there is a proliferation of hydrogen as a fuel in the future (Warwick et al., 2023).  It is well understood that atmospheric hydrogen has a positive indirect global warming potential (Ocko and Hamburg, 2022; Sand et al., 2023).  However, substantial uncertainty remains in evaluating this global warming potential, and how this value depends on the distribution of emissions.  Principally, the most appropriate surface deposition scheme to use in models remains unclear (Paulot et al., 2021).

Motivated by the observation that the seasonal variability of station hydrogen measurements (from Petron et al., 2023) can be well described as a function of latitude, we present an idealised latitude-height model for testing prototype deposition schemes.  We show how much of the key features of the seasonal variability can be captured with an illustrative benchmark deposition scheme, and finally how this model can be used to iteratively develop existing deposition schemes (e.g. Bertagni et al., 2021).

How to cite: Tardito Chaudhri, A. and Stevenson, D.: A Simple Approach for Atmospheric Hydrogen Modelling Based on the Seasonal Variability, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6038, https://doi.org/10.5194/egusphere-egu24-6038, 2024.

There are close to 6000 megaconstellation satellites in low-Earth orbit comprising 65% of all satellites orbiting Earth. The growth in satellite megaconstellations has driven surges in rocket launches and re-entry destruction of spent satellites. This has contributed to large increases in emissions of pollutants that are very effective at depleting stratospheric ozone and altering climate, due to direct injection of pollutants into the upper layers of the atmosphere where turnover rates are very slow. An additional 540,000 megaconstellation satellites are proposed, yet the environmental impacts of emissions from current and future satellite megaconstellations remain uncharacterized and unregulated. Here we calculate emissions of the dominant pollutants from megaconstellation and non-megaconstellation rocket launches and re-entries from 2020 to 2022 to determine the effect on climate and stratospheric ozone. Pollutants include black carbon (BC), nitrogen oxides (NOx≡NO+NO2), water vapour (H2O), carbon monoxide (CO), alumina aerosol (Al2O3) and chlorine species (Cly≡HCl+Cl2+Cl) from rocket launches and nitrogen oxides (NOx≡NO) and alumina aerosol (Al2O3) from re-entries. Launch emissions are calculated by determining the vertical distribution of propellant consumption for each rocket stage and calculating and applying vertically resolved propellant specific emission indices that account for additional oxidation in the hot rocket plume and changes in atmospheric composition with altitude. To quantify the re-entry emissions, the mass of re-entering objects is compiled for all objects (spacecraft, rocket stages, fairings, and components) re-entering Earth’s atmosphere in 2020-2022. Many objects, accounting for 12-16% of re-entry mass, are not geolocated, so the longitude and latitude of re-entry is bounded by the reported orbital inclination. Object class and object reusability are used to define the chemical composition and mass ablation profile of each re-entering object. We find that total propellant consumed has nearly doubled from ~38 Gg in 2020 to ~67 Gg in 2022 and re-entry mass has increased from ~3.3 Gg in 2020 to ~5.6 Gg in 2022. Megaconstellation re-entries accounted for 8-12% of the Al2O3 and NOx re-entry emissions in 2020-2022, due to increased megaconstellation launches and short (~2 years) lifespan of most (85%) megaconstellation satellites. Anthropogenic re-entry emissions of NOx (~4.2 Gg) and Al2O3 (~0.96 Gg) in 2022 equal a third of the natural meteoritic injection of NOx and surpass the natural injection by 7 times for Al2O3. The annual emissions for 2020-2022 will be used to predict the rise in emissions up to 2029 from megaconstellation and non-megaconstellation rocket launches and object re-entries for input to the 3D atmospheric chemistry transport model GEOS-Chem coupled to a radiative transfer model to simulate stratospheric ozone depletion and radiative forcing attributable to a decade of satellite megaconstellation emissions.

How to cite: Barker, C., Marais, E., and McDowell, J.: Developing inventories of by-products from satellite megaconstellation launches and disposal to determine the influence on stratospheric ozone and climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6467, https://doi.org/10.5194/egusphere-egu24-6467, 2024.

EGU24-7558 | Orals | AS3.26

Understanding the benefits and risks of the hydrogen economy: the HYDRA project 

Rossella Urgnani, Noelia Ferreras Alonso, Alessio Bellucci, Oliver Wild, Kyriakos Panopoulos, Massimo Santarelli, Nathanael Poinsel, and Isella Vicini

The European Green Deal target of zero emissions by 2050, boosted by the energy crisis due to the Russian-Ukranian conflict, put decarbonisation at the forefront of policymakers’ and industries’ development plans. Hydrogen, especially if produced by renewable energy sources, is considered one of the main candidates in the ongoing energy transition. The hydrogen economy is still in its early stages, due to the high cost of technologies, production, and infrastructure, but the electrolyser capacity installed in 2023 doubled 2022 levels (IEA report, 2023), with clear signs of increasing investments in this sector. However, large-scale diffusion of hydrogen technologies could negatively impact climate because of the increase in H2 emissions (through leakages or other mechanisms) to the atmosphere and its interactions with other gases. Hydrogen interacts with the oxidative cycles of CH4, NOx, and CO, affecting natural GHG-removing mechanisms. In addition, an increase in atmospheric hydrogen could alter stratospheric levels of ozone and water vapour. Increasing H2 emissions may result in an increase in global radiative forcing, even if H2 replaces a proportion of fossil fuel use. However, quantification of these impacts remains uncertain and depends on the development and uptake of different hydrogen technologies. The HYDRA project, funded by the European Commission under the Horizon Europe program, officially started on November 1st, 2023, and aims to evaluate the benefits and the potential risks associated with the hydrogen economy. It starts with the analysis of policies and markets to quantify the potential diffusion of hydrogen technologies in the mid-to-long term and the associated emissions of H2 and other gases (e.g., CH4, H2O, NOX, methanol, NH3). Using these data, HYDRA will simulate the impacts of the integration of hydrogen in the energy sector using WILIAM, an Integrated Assessment Model accounting for interactions between society, economy, and the environment, which will produce a range of energy, land, and emission scenarios. The FRSGC/UCI Chemical Transport Model will then be used to quantify global and regional impacts on O3, CH4, NOX, VOC, CO, and other oxidants, estimating the uncertainty in the important soil sink of hydrogen. The role of H2 in influencing stratospheric water vapour, ozone, and nitrous oxide (N2O) will be determined with the SLIMCAT and UKCA models. The changes in atmospheric composition from these simulations will be used to estimate the effective radiative forcing associated with H2 emissions and perform future climate projections, using the EC-Earth global climate model. Finally, since hydrogen-air mixes are highly inflammable, HYDRA will develop a new leakage detection/quantification monitoring system to make H2 technologies safer. The overall benefits and risks associated with a future hydrogen economy will be evaluated from a sustainable perspective, from changes in mean climate conditions to impacts on society and environment. HYDRA is fully committed to finding sustainable solutions for the development of the hydrogen economy, and to proposing mitigation strategies and guidelines for policymakers at the end of the 4-year project.

How to cite: Urgnani, R., Ferreras Alonso, N., Bellucci, A., Wild, O., Panopoulos, K., Santarelli, M., Poinsel, N., and Vicini, I.: Understanding the benefits and risks of the hydrogen economy: the HYDRA project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7558, https://doi.org/10.5194/egusphere-egu24-7558, 2024.

EGU24-9653 | Orals | AS3.26

Impact of hydrogen on atmospheric composition and climate 

Tanusri Chakraborty, Gill Thornhill, and Bill Collins

Hydrogen(H2) is one of the most abundant greenhouse gases in the atmosphere that participates in stratospheric ozone depletion and influences air quality. Using hydrogen as an alternative energy source to meet net-zero carbon emissions by 2050 can increase the risk of Hydrogen Leakage. Excess H2 leaked from a hydrogen economy could travel from the Earth’s surface to the stratosphere, where its oxidation would increase water vapor (H2O) in the upper atmosphere. It also has the potential to modify stratospheric ozone destruction by altering catalytic reactions involving HOx (=OH+HO2) radicals as well as changing stratospheric temperatures. Additional H2 in the air would consume the hydroxyl radical (OH) and lengthen the atmospheric lifetime of methane (CH4), increasing its abundance, whilst the oxidation of both H2 and CH4 generates tropospheric O3. The changes in OH can cause a cascade of climate impacts that includes changes in aerosol clouds. Increases in H2 will increase the concentration of CH4, O3, and H20, resulting in increased radiative forcing. Here, we are using the UK Earth System Model (UKESM) chemistry-climate model to see the effect of indirect radiative forcing arising from increases in H2 in the atmosphere. We have conducted experiments at present and future H2 and CH4 concentrations and analyzed the feedback on O3, aerosol, and stratospheric H2O over the period of 40 years. The highlight of the study is to see the effects of radiative forcing on CH4, O3, and H2o separately . We have seen the effect on one component at a time by switching off the feedback of the other components and also see the effect of radiative forcing as a whole due to an increase in H2 concentration.

How to cite: Chakraborty, T., Thornhill, G., and Collins, B.: Impact of hydrogen on atmospheric composition and climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9653, https://doi.org/10.5194/egusphere-egu24-9653, 2024.

When hydrogen is used as an energy carrier, some hydrogen will leak into the atmosphere during production, storage, transport, and end use. Hydrogen itself is not a greenhouse gas, but via chemical reactions in the atmosphere, the leaked hydrogen will affect the atmospheric composition of methane, ozone, and stratospheric water vapor and hence radiation in the atmosphere. A recent multi-model study found the Global Warming Potential over a 100-year time horizon (GWP100) to be 11.6 ±2.8 (one standard deviation). In this study, a chemistry transport model (OsloCTM3) is used to investigate the sensitivity of the calculated GWP100 due to the size of the hydrogen perturbation, the location of the hydrogen perturbation as well as the chemical composition of the background atmosphere.

The hydrogen perturbation of an additional 0.1, 1, 10 and 100 Tg yr-1 of anthropogenic hydrogen emissions gave GWP values that differed by only 0.4. To test the sensitivity of the location of the perturbation, 1 Tg yr-1 was added to seven different sites around the world. Perturbations at sites that are further away from dry deposition areas (such as middle of the ocean and in Antarctica) resulted in feedback factor larger than one. The GWP values were enhanced compared to perturbations at sites influenced more by dry deposition where feedback factor was less than one. The difference in GWP100 between the two most extreme sites was 4, less than the width of the ± one standard deviation range from the multi-model GWP100 study.

The hydrogen economy is expected to grow, and in the future, the atmospheric composition might be different than the 2010 atmosphere used to calculate GWP100 in the multi-model study. To check the sensitivity to this the GWP100 is calculated with the perturbations on top of three different 2050 atmospheres using different SSP scenarios. The three different SSPs had different combinations of NOx to CO emission ratios and methane levels that both influence the atmospheric lifetime of hydrogen. The atmospheric lifetime increased in all the scenarios, and in SSP4-3.4 by as much as ~1 year. However, the dominant control on the total lifetime of hydrogen is the soil sink. Thus, future changes to the soil sink should be investigated, with a focus on how it influences the calculated GWP.

How to cite: Skeie, R. B.: Sensitivity of climate effects of hydrogen to leakage size, location, and chemical background, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9851, https://doi.org/10.5194/egusphere-egu24-9851, 2024.

EGU24-10002 | Orals | AS3.26

Improving quantification and understanding of the global H2 soil sink through field and lab based flux measurements 

Nicholas Cowan, Julia Drewer, Toby Roberts, Mark Hanlon, Chiara Di Marco, Carole Helfter, and Eiko Nemitz

An improved quantification of the soil sink of Hydrogen (H2) gas is required to understand the environmental implications of a future Hydrogen economy and global atmospheric models. Typically, soil microbes utilise H2 as an energy source, but we also have evidence that emission of H2 from soils is also possible via microbial processes. We present new H2 flux data from several field sites and lab studies in which a variety of soils from around the world have been measured from. These sites include agricultural and forest soils from the UK where we have preliminary data of a longer-term measurement campaign. We have developed flux chamber methodology to establish a best practice for measuring H2 flux in soils, which is radically different from typical greenhouse gas protocols. We present our work so far on the development of H2 measurement methodology and on the characterisation of the H2 soil sink in relation to soil physical & chemical properties, vegetation and climate under controlled environment conditions. We also present observations of spatial and temporal soil H2 uptake rates from sites across the UK. We highlight the importance of soil aeration and the physical barriers that strongly interfere with H2 uptake in soils, particularly the influence of high water-filled pore space which should be accounted for in future modelling efforts.

How to cite: Cowan, N., Drewer, J., Roberts, T., Hanlon, M., Di Marco, C., Helfter, C., and Nemitz, E.: Improving quantification and understanding of the global H2 soil sink through field and lab based flux measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10002, https://doi.org/10.5194/egusphere-egu24-10002, 2024.

EGU24-10067 | ECS | Orals | AS3.26

Detection of regional industrial H2 emissions using an active Aircore and a high-precision GC-PDHID system 

Iris M. Westra, Bert A. Scheeren, Steven M.A.C. van Heuven, Bert A.M. Kers, and Harro A.J. Meijer

As result of the global energy transition, it is expected that H2 emissions are on the rise due to increasing production, transport and usage. Leakage rates might be up to 10% of the total hydrogen production. This will lead to an increase of the global atmospheric hydrogen mole fraction, resulting in the lengthening of the lifetime of in particular methane, enhanced tropospheric ozone production, and increased stratospheric water vapor levels. Because of these effects, H2 is called an indirect greenhouse gas. We present first results of the use of a high-precision Agilent 8890 GC-system equipped with a Pulsed Discharge Helium Ionization Detector (PDHID) combined with an ‘active’ Aircore and sampling flasks as a tool to detect and quantify industrial H2 emissions. Our GC-PDHID measures H2 with a precision <2 ppb and is calibrated and linked to the international NOAA-H2-X1996 hydrogen scale (e Max Planck Institute for Biogeochemistry (MPI-BGC) Jena, Germany). The ‘active’ AirCore is an atmospheric sampling system that consists of a long narrow tube (in the shape of a coil) in which atmospheric air samples are collected using a pump during the sampling experiment, in this way preserving a profile of the trace gas of interest along the measurement trajectory. In this study we focus on potential H2 emitters in the Groningen province, mainly located at the Delfzijl Chemistry Park bordering the Wadden sea coast. During our field experiments we deployed three different complementary sampling methods. The first method involves the use of an active Aircore system with a sample volume of 4.35 L from a passenger car. This Aircore is filled to an end-pressure of up to 1.6 bar over the course of about 2 hours of sampling resulting in up to 38 discrete Hsamples on the GC-PDHID. The second method involved the use of an active Aircore system on a UAV with a volume of 3.7 L and filled with a sampling flow of 200 ml min-1 at atmospheric pressure, allowing for up to 21 discrete Hsamples. The third sampling technique involved the use of dried and vacuumized 2.3 L glass flasks to collect discrete samples along the measurement trajectory. The glass flasks samples were further analysed by CRDS (Picarro G2401) on mole fractions of CO2, CH4, CO, to get additional information on the emission sources co-located with H2. We found a regional H2 background of 529 ± 5 ppb in agreement with the European background station observations at Mace Head, Ireland. Our results so far indicate constant undetected industrial H2 emissions at the Chemistry Park Delfzijl, ranging from enhanced signals of 580 ppb up to 1.5 ppm of H2 downwind the source area. Based on these results we present first estimates of current industrial H2-emissions from the Delfzijl Chemistry park. Further work will focus on specific H2 production and storage infrastructure.

How to cite: Westra, I. M., Scheeren, B. A., van Heuven, S. M. A. C., Kers, B. A. M., and Meijer, H. A. J.: Detection of regional industrial H2 emissions using an active Aircore and a high-precision GC-PDHID system, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10067, https://doi.org/10.5194/egusphere-egu24-10067, 2024.

EGU24-10187 | ECS | Posters on site | AS3.26

Analysis of trade-offs from the use of hydrogen blended with natural gas in the European Union 

Thiago Brito, Lena Höglund-Isaksson, Peter Rafaj, Robert Sander, and Zbigniew Klimont

Context: Increasing use of hydrogen (H2) across the economy is currently seen as an important strategy for decarbonization of fossil fuel-dependent sectors. Energy scenarios, especially those aiming at net-zero GHG emission targets, project that surplus electricity produced from renewable sources, such as solar and wind, will be converted and stored as H2 by electrolysis. The use of pure hydrogen would require the replacement or significant modification of some of the infrastructure (e.g. steel pipelines) and end-use appliances (e.g. combustion engines) by H2-dedicated equipment (e.g. PE/PVC pipelines, fuel cells); in fact, many sectors are already moving towards these solutions. However, hydrogen can also be blended into natural gas and used in the same applications. The combustion of such blends enables reduction of carbon intensity in several sectors without significant technological retrofits. However, hydrogen combustion under lean air conditions leads to higher thermal formation of nitrogen oxides (NOx), when compared to natural gas. The amount depends on the burner type, load and hydrogen blending ratio. While NOx emissions pose a direct risk to human health and act as a precursor to the O3 and particulate matter, deployment of H2 would also result in direct leakages to atmosphere and associated climate impacts.

Objective: This study seeks to quantify and evaluate the potential NOx increases in the European Union (EU27) countries due to the combustion of hydrogen blended with natural gas.

Methodology: We use GAINS model framework to conduct this analysis assuming that hydrogen combustion will mostly take place in the buildings, industry (boilers and furnaces) and power generation sectors. The exclusion of the transport sector is justified by the predominant use of hydrogen in fuel cell vehicles, which do not contribute to NOx formation. Since hydrogen blends will be used in the same devices as currently natural gas, existing abatement technologies as well as their adoption rates are kept across all sectors and regions.

Expected Results: We expect the results of this study will allow us a better understanding of hydrogen impacts in terms of pollutant emissions. While the paper asserts that the findings are unlikely to influence the development or viability of future hydrogen economies in Europe, it acknowledges the importance of the analysis in revealing potential emissions trends and identifying local or country-specific trade-offs. The emphasis on existing regulations and emission control strategies in Europe provides context for the limited air quality impacts expected on the overall trajectory of hydrogen adoption. Moreover, these preliminary results could lead to relevant insights regarding expected H2 fugitive emissions which may impact climate mitigation targets and economical viability. 

How to cite: Brito, T., Höglund-Isaksson, L., Rafaj, P., Sander, R., and Klimont, Z.: Analysis of trade-offs from the use of hydrogen blended with natural gas in the European Union, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10187, https://doi.org/10.5194/egusphere-egu24-10187, 2024.

EGU24-10918 | ECS | Posters on site | AS3.26

The Impacts of Hydrogen on Tropospheric Ozone and their Modulation by Background NOx 

Hannah Bryant, David Stevenson, Mathew Heal, and Maria Sand

A shift in our energy production is crucial to the control of global warming. This will occur as fossil fuels are phased out, following legislation created to reach the targets set out in the Paris Agreement. One of the possible sources for a low carbon energy landscape is renewable hydrogen. Whilst hydrogen represents an alternative energy store, it can leak from the system. Understanding the fate of leaked hydrogen is vital to quantify the implications of this energy transition. This study uses the atmospheric version of the United Kingdom Earth System Model to analyse the impact of hydrogen on the atmosphere. The model indicates that increased atmospheric hydrogen leads to an increase in tropospheric ozone concentrations. Ozone is a greenhouse gas and therefore there is an indirect atmospheric warming due to hydrogen emission through ozone. Understanding the relationship between hydrogen and the chemical ozone budget is therefore required to dissect how this warming occurs. We find that hydrogen increases ozone production, governed by the increased flux through the reaction of HO2 with NO. Future atmospheric nitrogen oxide concentrations are expected to decrease in the coming decades, under most climate scenarios. Understanding the relationship between hydrogen and background NOx concentrations is therefore crucial in determining the mechanisms of how hydrogen is expected to impact future atmospheres. We use the model to calculate the tropospheric global warming potential of hydrogen and how this is altered by changing background NOx. We find that this tropospheric GWP will stay relatively constant alongside decreases in ground level anthropogenic NOx.

How to cite: Bryant, H., Stevenson, D., Heal, M., and Sand, M.: The Impacts of Hydrogen on Tropospheric Ozone and their Modulation by Background NOx, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10918, https://doi.org/10.5194/egusphere-egu24-10918, 2024.

EGU24-11016 | Orals | AS3.26 | Highlight

The climate impact of a future hydrogen economy 

Didier Hauglustaine

Inflammable air, known today as hydrogen, was first identified and produced in 1766 by the British chemist and physicist Henry Cavendish. Today, hydrogen can be produced by splitting the liquid water molecules. The water electrolysis producing hydrogen can be powered by renewable energy in the case of "green" hydrogen. Hydrogen is also produced from fossil fuels by steam reforming of methane in natural gas in conjunction with carbon sequestration in the case of "blue" hydrogen, or without carbon sequestration in the case of "grey" hydrogen. The use of hydrogen enables energy conversion and storage, and can provide a way to decarbonize sectors of the economy where decarbonization has no alternative or is hard to reach, such as long-distance transport by truck, train or airplane, heavy industries, or for domestic use in mixture with natural gas. Hydrogen has no direct greenhouse effect but is an indirect climate gas which induces perturbations of atmospheric methane, ozone and water vapour, three powerful greenhouse gases. The budget of atmospheric molecular hydrogen will be presented and the main sources and sinks will be briefly discussed. Based on the results of state-of-the-art global numerical climate and chemistry models, we derive various indicators intended to quantify the climate impact of hydrogen and in particular derive its Global Warming Potential (GWP).

All the scenarios considered in this study for a future transition towards a hydrogen economy in Europe or in the world clearly suggest that a "green" hydrogen economy is beneficial in terms of CO2 emissions mitigation for the relevant time horizons and leakage rates considered. In contrast, the results suggest that carbon dioxide (CO2) and methane (CH4) emissions associated with the production and transport of "blue" (and "grey") hydrogen reduce the climate benefit of such a transition and even introduce a climate penalty in the event of a very high leakage rate or strong penetration of "blue" hydrogen on the market. Various assumptions will be illustrated for future “blue” hydrogen production carbon intensity. Reducing the leakage rate of H2 (and CH4 in the case of "blue" hydrogen production) and increasing the "green" hydrogen production sector appear to be the key levers towards maximum mitigation of CO2 emissions from a large-scale structural transition to a hydrogen economy.

In addition, in the specific case of aviation, the use of liquid hydrogen powered aircraft induces additional climate forcings from water vapour emissions in the upper atmosphere and from impact on contrail formation. In the case of an hydrogen powered fleet, the forcings from NOx and from contrails are still subject to large uncertainties. These effects will be illustrated based on various assumptions for future aircraft using hydrogen fuel.

 

How to cite: Hauglustaine, D.: The climate impact of a future hydrogen economy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11016, https://doi.org/10.5194/egusphere-egu24-11016, 2024.

EGU24-12262 | Posters virtual | AS3.26

Impact of Hydrogen and Ammonia on Surface Air Pollution. 

Caroline Jouan, Øivind Hodneborg, and Ragnhild Skeie

Hydrogen and ammonia fuels are being explored as cleaner and sustainable energy alternatives to fossil fuels, due to their potential for decarbonization. The production of renewable energy-based hydrogen converted into green ammonia offers a more efficient solution for storing and transporting energy than gaseous hydrogen. However, both ammonia and hydrogen can indirectly lead to air pollution.

Ammonia, if leaking to the atmosphere, plays a role in forming secondary aerosols, generating particles like ammonium nitrate that add to fine particulate matter (particulate matter with diameter <2.5 micrometers; PM2.5). Additionally, the production of oxides of nitrogen (NOX) gases during ammonia combustion contributes to tropospheric ozone formation and can influence aerosol abundance (as NOX may lead to less aerosols and not necessarily more). Hydrogen, if leaked to the atmosphere, will impact tropospheric ozone and possible aerosols through a complex chain of chemical reactions.

Our research aims to assess the potential air quality effects of shifting to a hydrogen and ammonia-based economy.

Using simulations from the three-dimensional global chemical transport model (OsloCTM3), we are investigating the impacts of hydrogen and ammonia on key air quality parameters, with a specific focus on surface concentrations of ozone and PM2.5.

We will attempt to assess the benefits of this energy transition in relation to the reduction of atmospheric pollutants associated with fossil fuels. In the case of ammonia, we will compare air pollution impacts across different emission sectors. Future work will involve the analysis of chemistry-climate model simulations.

How to cite: Jouan, C., Hodneborg, Ø., and Skeie, R.: Impact of Hydrogen and Ammonia on Surface Air Pollution., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12262, https://doi.org/10.5194/egusphere-egu24-12262, 2024.

EGU24-14242 | ECS | Orals | AS3.26

Quantifying leaks with a field-deployable, fast, sensitive hydrogen instrument 

Elizabeth Lunny, Richard Wehr, Joseph Roscioli, Conner Daube, Joanne Shorter, Tianyi Sun, William Long, Ahmad Momeni, John Albertson, Scott Herndon, and David Nelson

Accurate quantification of leaks associated with hydrogen transport and storage infrastructure is vital to evaluate the environmental benefit associated with the transition from fossil fuels to hydrogen as an energy source. Understanding the locations and magnitudes of leaks is critical in efforts to mitigate the indirect climate impact of transitioning to a hydrogen economy. Quantification of hydrogen leaks requires a field-deployable, fast, sensitive measurement technology which, until recently, has not existed. We have developed a novel inlet system which couples to an Aerodyne tunable infrared laser direct absorption spectrometer (TILDAS) to measure hydrogen with <5 ppb precision and <5 second time response. Laboratory-based instrument performance results and data from recent mobile measurements will be presented.

How to cite: Lunny, E., Wehr, R., Roscioli, J., Daube, C., Shorter, J., Sun, T., Long, W., Momeni, A., Albertson, J., Herndon, S., and Nelson, D.: Quantifying leaks with a field-deployable, fast, sensitive hydrogen instrument, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14242, https://doi.org/10.5194/egusphere-egu24-14242, 2024.

EGU24-16477 | ECS | Posters on site | AS3.26

Modelling the Global Uncertainty of Hydrogen Deposition 

Megan Brown, Alex Archibald, Luke Abraham, Nicola Warwick, and Paul Griffiths

Using hydrogen as an alternate fuel source could lead to lower carbon emissions if sourced from renewable energies. However, it can act as an indirect greenhouse gas by extending the lifetime of methane and causing stratospheric water vapour to increase. The global production and loss of hydrogen in the atmosphere are important in order to quantify its lifetime and, by extension, its global warming potential. The main sinks for hydrogen are loss through chemical reactions with OH and biological soil uptake, the latter of which accounts for approximately 80% loss and, on average, has an error range of +/-40%. Due to the wide potential range of deposition velocities and its large global impact on hydrogen, this introduces a major uncertainty to the overall hydrogen budget.

Previously in the UK Chemistry and Aerosol model (UKCA), the soil uptake of hydrogen was fixed temporally and depended on land type, following the scheme by Sanderson et al. (2003). We have implemented the deposition scheme from Paulot et al. (2021) into UKCA in order to better represent the uptake of hydrogen. A wide range of soil parameters are used in the updated scheme: soil moisture, temperature, snow depth, soil carbon content, soil type, and soil saturation content, which allow for a more diverse and dynamic range of deposition velocities. These results from UKCA are evaluated against previous global hydrogen budgets and verified against hydrogen observations from the National Oceanic and Atmospheric Administration.

The calculation of hydrogen deposition velocity onto soil is independent of atmospheric hydrogen, and, as a result, can be calculated offline. We use data from CMIP6 simulations as inputs to calculate a range of global hydrogen deposition velocities across multiple future projections using a range of different deposition models. The different uncertainties associated with models (hydrogen deposition and climate models) natural variation, and future scenarios can be isolated. Fluctuations in deposition and variation through time can be analysed to assess the which factors have the greatest contribution to the hydrogen deposition velocity uncertainty.

How to cite: Brown, M., Archibald, A., Abraham, L., Warwick, N., and Griffiths, P.: Modelling the Global Uncertainty of Hydrogen Deposition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16477, https://doi.org/10.5194/egusphere-egu24-16477, 2024.

EGU24-16712 | ECS | Orals | AS3.26

Climate effects of contrail cirrus for aircraft with hydrogen combustion    

Susanne Pettersson and Daniel Johansson

Aviation accounts for approximately 5% of the current anthropogenic climate impact. Up to two thirds of the warming generated by airplanes is attributed to non-CO2 effects with contrail cirrus as the largest contributor. Hydrogen as aviation fuel promises zero carbon emission but the non-CO2 effects of this new fuel are poorly known.

In this study we investigate the generation of contrail cirrus from hydrogen combustion using a modified version of the Contrail Cirrus Prediction model (CoCip). In the absence of soot-emissions ice particles in hydrogen contrail are assumed to form on entrained aerosols, ultrafine volatile particles and lubrication oil. The calculation of the number of ice particles formed on entrained aerosols is approximated by previously published simulation results and theory.  Ultrafine volatile particles and lubrication oil both activate into water droplets at lower temperatures than soot and aerosols due to the Kelvin effect (small radius) and hydrophobicity respectively and are implemented using theory and published experimental results.

Using hydrogen fuel contrails can, according to the Schmidt-Appleman criteria, form at lower altitudes than with jet fuel due to the increase in water vapor in the exhaust. Despite this our preliminary results show an overall decrease in both warming and cooling contrails for hydrogen compared to standard jet fuel. We do find that hydrogen contrails can generate more radiative forcing than jet contrails at very low temperatures mainly due to the activation of lubrication oil in combination with the larger amount of water vapor. For the bulk of flights however, hydrogen fuel leads to either equal or less contrail radiative forcing than jet fuel even with reduced soot-emissions in line with lean-burn engines.   

How to cite: Pettersson, S. and Johansson, D.: Climate effects of contrail cirrus for aircraft with hydrogen combustion   , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16712, https://doi.org/10.5194/egusphere-egu24-16712, 2024.

Hydrogen fuel, a green transition option and a cleaner alternative to fossil fuels, has an indirect greenhouse impact through atmospheric reactions of “leaked” hydrogen. Sand et al., 2023 used six different chemistry-transport models (CTM) to estimate a Global Warming Potential over a 100-year time horizon (GWP-100) for hydrogen of 11.6 ± 2.8, in range with similar studies. In this study, we extend those analyses by investigating the atmospheric production and loss terms of hydrogen in the CTMs. Specifically, we compare formaldehyde (HCHO) and the hydroxyl radical (OH) concentrations. Then we develop a box model that can be used for quickly evaluating the impact of the different sources and sinks on atmospheric concentration and isotopic composition of H2 from a global perspective.

Atmospheric production of hydrogen through photo-oxidation of methane and volatile organic compounds represents roughly 60% of the total production. To compare the atmospheric production in the models, we evaluate HCHO (produced during photo-oxidation). A preliminary comparison between the global mean model-derived tropospheric HCHO and TROPOMI-derived HCHO suggests that all models other than WACCM perform reasonably well. Generally, models tend to overestimate HCHO values over land and underestimate HCHO concentrations over the oceans. WACCM has very low HCHO values compared to TROPOMI and the other models.

The two primary removal mechanisms are soil uptake (65-85%), and atmospheric oxidation by hydroxyl radical (OH). Among the models, OsloCTM3 and WACCM have higher OH concentrations compared to GFDL, INCA and UKCA. Direct measurements of atmospheric OH concentrations are lacking due to the short lifetime of the OH radical. Therefore, we used CO and NO2 concentrations as a proxy to evaluate the models. Compared to satellite values (TROPOMI for NO2 and MOPPIT for CO), models seem to generally overestimate NO2 and underestimate CO. These results are discussed within the context of the OH radical and atmospheric lifetime of H2.

Then we present a simple box model that is developed using CTM results for studying the atmospheric budget of H2. Reconstructions of hydrogen concentrations using ice-core records from the South Pole over the last 150 years show an increase in H2 concentration of ~200ppb, likely due to increased methane oxidation and anthropogenic emissions. We use time-varying emissions in our box model to replicate this time evolution since the pre-industrial period.

The box model also contains a framework for studying hydrogen isotopic composition. Each of the sources and removal processes of H2 have distinct isotopic signatures. This allows for the evaluation of concurrent changes in atmospheric concentrations and hydrogen isotopic compositions for each source/sink contribution, leading to a more robust evaluation of the hydrogen budget in the atmosphere.

How to cite: Krishnan, S.: Atmospheric hydrogen budget: an evaluation using chemistry-transport models and a box model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16977, https://doi.org/10.5194/egusphere-egu24-16977, 2024.

EGU24-19183 | ECS | Posters on site | AS3.26

Fugitive hydrogen emissions from a converted national UK network of methane pipelines – stratospheric climate impacts 

Anna Peecock, Lars Schewe, and Stuart Haszeldine

Increased fugitive hydrogen in the stratosphere can promote chemical reactions that result in increased lifetimes and abundances of gases that have a harmful climate impact. It is therefore crucial to understand the significance of this effect, and thereon identify and mitigate potential leakage pathways within future hydrogen energy systems. Repurposing the existing high-pressure National Transmission System and low pressure local gas distribution networks for pure or blended hydrogen delivery throughout the UK, is a solution favoured by existing gas network operators. It minimises the necessary replacement of pipeline infrastructure by re-use of £30bn of already installed welded polythene pipe network and compatible assets, which will decrease associated transport costs. However, gaseous hydrogen can compromise mechanical properties of carbon steels, posing integrity concerns for pipelines and other network components. Considerable work has investigated the extent to which material integrity could affect the repurposing potential of existing infrastructure. By contrast, this study aims to quantify the ranges of anticipated increase in atmospheric hydrogen release upon conversion of existing UK gas networks for hydrogen delivery. Based on existing network architectures, provided by UK network operators, we identify the most likely locations for leakage within UK pipeline networks and present a static model to estimate potential fugitive hydrogen. Sensitivity analyses have been undertaken to assess the impact of emissions mitigation strategies, including polythene renewal in the Iron Mains Replacement Programme and replacement of wet compressor seals. Consequently, we can consider both physical leakage at joints and equipment, and permeation losses through pipe walls from natural gas leakage data. Our findings indicate that, while significant, the climate implications of determined theoretical rates of potential hydrogen leakage without mitigation are between 6.5 and 14 times less than those associated with current natural gas transport, based on respective GWP100s. It should be noted that we have considered only the potential emissions associated with pipeline transport, and have thus ignored the additional impact of embedded supply chain emissions.

We further propose a geospatial distribution of these potential hydrogen emissions across the UK network. The dataset could serve as a crucial input for future climate modelling to assess the impact of emission location dependency on hydrogen’s global warming potential and quantify the benefits of mitigating leakage in identified “hotspots”. 

How to cite: Peecock, A., Schewe, L., and Haszeldine, S.: Fugitive hydrogen emissions from a converted national UK network of methane pipelines – stratospheric climate impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19183, https://doi.org/10.5194/egusphere-egu24-19183, 2024.

EGU24-20693 | Posters on site | AS3.26

Quantifying the role of interactive chemistry on the anthropogenic effective radiative forcing in Earth System Models 

Jane Mulcahy, Martin Cussac, Dirk Olivie, Pierre Nabat, Martine Michou, and Juliette Lathiere

Many global climate and Earth system models that participated in CMIP6 did not include fully interactive chemistry mechanisms mainly due to the large associated computational cost of these schemes. A number of studies have recently highlighted the potential importance of enhanced aerosol-chemistry-climate coupling and associated feedbacks for the anthropogenic effective radiative forcing (ERF) of a number of key climate forcing agents such as aerosols (Thornhill et al., 2021), methane (O’Connor et al., 2022) and ozone. The different levels of complexity in both aerosol and chemistry schemes in CMIP6 models has been highlighted as a leading contributor to the large inter-model diversity in the ERF of aerosols and trace gas species (Thornhill et al., 2021). To this end, as part of the EU Horizon project, ESM2025, advanced stratospheric-tropospheric chemistry schemes have been developed and implemented in 2 ESMs, CNRM-ESM and NorESM2, for the first time. Dedicated experiments have been conducted to determine the pre-industrial (1850) to present-day (2014) ERF with these updated models and the UKESM1.1 model, to assess the impact of fully interactive chemistry on the ERF of key forcing agents. In UKESM1.1, which already includes interactive chemistry, the interactive chemistry scheme is switched off and run with a much-simplified aerosol-chemistry mechanism driven by prescribed oxidant fields. We argue the improved realism of representing these aerosol-chemistry-climate interactions is essential for improved cross-model consensus on the magnitude of anthropogenic ERFs of aerosol and key trace gas species.

References:

Thornhill et al., Effective radiative forcing from emissions of reactive gases and aerosols – a multi-model comparison, Atmos. Chem. Phys., 21, 853–874, https://doi.org/10.5194/acp-21-853-2021, 2021.

O’Connor et al., Apportionment of the pre-industrial to present-day climate forcing by methane using UKESM1: The role of the cloud radiative effect. Journal of Advances in Modeling Earth Systems, 14, e2022MS002991. https://doi.org/10.1029/2022MS002991, 2022.

How to cite: Mulcahy, J., Cussac, M., Olivie, D., Nabat, P., Michou, M., and Lathiere, J.: Quantifying the role of interactive chemistry on the anthropogenic effective radiative forcing in Earth System Models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20693, https://doi.org/10.5194/egusphere-egu24-20693, 2024.

EGU24-1070 | ECS | Orals | BG8.9

Understanding spatio-temporal pattern of crop diversification for India 

Chanda Kumari, Roopam Shukla, and Stephanie Gleixner

Abstract: Agrobiodiversity, a key principle of agroecology, encompasses crop diversification, offering resilience to climate variability (Ronnie Vernooy, 2022). Increasing crop species diversity within a region could improve agricultural sustainability, but knowledge of the spatiotemporal variation of crop species diversity and how this is related to climatic conditions is limited (Sjulgård, H., et al., 2022). Higher crop diversity may alleviate the effects of heat stress (Degani et al., 2019, Marini et al., 2020) and drought (Bowles et al., 2020, Marini et al., 2020) on crop yields. Therefore, crop diversity will play a crucial role in the functioning of agroecosystems under climate change (Sjulgård, H., et al., 2022). Hence, this study aims to investigate the relation between the spatiotemporal pattern of crop diversity and changing climatic conditions at the district level in India by building relationship between crop diversification and climatic variables. Crop species diversity was estimated using the Shannon Index. Advanced statistical analysis was used to understand the relationship between climatic variables and crop diversity. The outcome will also help the policymaker, researchers, and field practitioners in designing climate-resilient agricultural practices following the principles of agroecology.

Keywords:

Crop diversification, Shannon Index, Climate variables, Risk map, Agrobiodiversity, Agroecology, India.

Figure 1: Schematic representation of the proposed work

How to cite: Kumari, C., Shukla, R., and Gleixner, S.: Understanding spatio-temporal pattern of crop diversification for India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1070, https://doi.org/10.5194/egusphere-egu24-1070, 2024.

EGU24-1392 | ECS | Posters on site | BG8.9

A novel composite Index for early-season maize mapping 

Yuan Gao, Yaozhong Pan, Shoujia Ren, and Chuanwu Zhao

Maize cultivation significantly contributes to global food security and sustains human livelihoods. Efficient early-season maize mapping is pivotal for forecasting production and informed pre-harvest decisions. Existing approaches rely on prolonged phenological data or available crop labels, limiting their applicability in areas lacking comprehensive data. Thus, an automated, dynamic, and accurate maize identification method for the early growing season is crucial. This study explores spectral bands to distinguish maize early in terms of water content and chlorophyll levels. A novel composite index for dynamic maize identification independent of labels was proposed. Utilizing this index with a multi-temporal Gaussian Mixture Model facilitated early-season maize mapping and identification. Assessments across diverse global regions revealed the method's robustness, consistently achieving 90% accuracy and F1-score. NDCI outperformed other indices, enhancing F1-score by up to 30%. NDCI-mGMM accurately generated maize maps two months pre-harvest, promising an F1 score of at least 77%. Operating autonomously from labels, this framework offers swift and precise maize identification in data-deficient regions, revolutionizing global food security and trade forecasts.

How to cite: Gao, Y., Pan, Y., Ren, S., and Zhao, C.: A novel composite Index for early-season maize mapping, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1392, https://doi.org/10.5194/egusphere-egu24-1392, 2024.

EGU24-2876 | Posters on site | BG8.9

Modelling greenhouse gas emissions at farm level across Switzerland 

Jérôme Schneuwly, Anina Gilgen, and Daniel Bretscher

For a better understanding of the environmental impacts of the agricultural sector and based on federal regulation, the monitoring of the agri-environmental system of Switzerland (MAUS) is tracking the development of different environmental indicators, among them regional GHG emissions. For this purpose, we developed a GHG emission model to calculate farm-scale, yearly, management-influenced emissions.

The considered categories of greenhouse gas emissions largely follow the approach of Switzerland's national greenhouse gas inventory under the UNFCCC (FOEN, 2023), while adaptations in the calculation of emissions from manure management were implemented. Among them, the ALFAM2 (Hafner et al., 2019) methodology was used for slurry application emission estimation and slurry storage emission factors were revised based on the publication from Kupper et al. 2020.

The manure management part of the model depicts nitrogen flows along the manure cascade. At each step (1. barn, pasture, yard; 2. storage; 3. application), a fraction of total ammoniacal nitrogen is being lost as N2O, NH3, NOx or N2. CH4 emissions from manure management are calculated in parallel to the nitrogen containing emissions, following the methods of Soliva et al., 2006. NH3, N2O and CO2 emissions originating from mineral fertilizer, organic products and harvest residues are calculated by multiplying nitrogen or carbonate inputs with respective emission factors. Further, CH4 from enteric fermentation is implemented according to the 2019 IPCC guidelines for greenhouse gas inventories, taking into account gross energy intake. As exact and exhaustive data is not available for every single Swiss farm, data from various sources were combined and averaged on different levels if necessary.

Farm-based calculations allow to monitor the effects of management changes on GHG emissions and to summarize the results at different geographical resolutions depending on the goals of the according study. To analyze regional differences for MAUS, the emissions were summarized per municipality and set in relation to utilized agricultural area. Monte-Carlo-like simulations were run to examine sensitivities of individual input variables and uncertainties, which showed generally a large influence of animal numbers and milk urea concentrations on total farm GHG emissions.

Within MAUS, it is planned to calculate emissions annually to detect potential trends. Further, newly available data sources, like farm specific mineral fertilizer applications, will be considered to make more detailed calculations.

FOEN, 2023: Switzerland’s Greehouse Gas Inventory 1990-2021: National Inventory Document. Submission of April 2023 under the United Nations Framework Convention on Climate Change. Federal Office for the Environment, Bern. URL: https://www.bafu.admin.ch/bafu/en/home/topics/climate/state/data/climate-reporting/ghg-inventories/latest.html (20.12.2023).

Hafner, S.D., Pacholski, A., Bittman, S., Carozzi, M., Chantigny, M., Génermont, S., Häni, C., Hansen, M.N., Huijsmans, J., Kupper, T., Misselbrook, T., Neftel, A., Nyord, T., Sommer, S.G., 2019. A flexible semi-empirical model for estimating ammonia volatilization from field-applied slurry. Atmospheric Environment 199, 474-484.

Kupper, T., Häni, C., Neftel, A., Kincaid, C., Bühler, M., Amon, B., VanderZaag, A., 2020. Ammonia and greenhouse gas emissions from slurry storage - A review. Agriculture, Ecosystems and Environment 300

Soliva, C.R., 2007. Dokumentation der Berechnungsgrundlage von Methan aus der Verdauung und dem Hofdünger landwirtschaftlicher Nutztiere. Federal Office for the Environment, Bern.

How to cite: Schneuwly, J., Gilgen, A., and Bretscher, D.: Modelling greenhouse gas emissions at farm level across Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2876, https://doi.org/10.5194/egusphere-egu24-2876, 2024.

EGU24-3443 | Orals | BG8.9 | Highlight

Integration of data from agricultural practice into the Swiss agri-environmental monitoring project MAUS 

Silvio Blaser, Simon Baumgartner, Jérôme Schneuwly, and Anina Gilgen

In order to fulfil the requirements of the Agriculture Act and the Ordinance on the Assessment of Sustainability, the Swiss Federal Research Centre Agroscope assesses the quantitative and qualitative impacts of agriculture on the environment using regional and farm-related eco-indicators. This is done by the monitoring of the Swiss agri-environmental system (MAUS).

Thematically, these indicators cover a wide range of agroecological hotspots, such as humus, heavy metal and nutrient balances, use and risks of plant protection products, potential impact on biodiversity, greenhouse gas emissions and others. Agroscope bases the calculation of the indicators largely on existing data. To supplement and improve the quality of this data, MAUS is currently launching projects to acquire and integrate data from remote sensing, online surveys and farm management information systems (FMIS).

Integrating FMIS data essentially means requesting data that is already collected by farmers for their farm management and in order to receive direct payments. A large part of this is field calendar data, which describes what happened in a field after the previous crop was harvested: e.g., how was the seedbed prepared, what fertilisation and plant protection measures were carried out before the crop was harvested, etc.

There are various large gaps in the level of detail and scope of the FMIS available on the market compared to what is needed to calculate the indicators. Therefore, solutions are needed that allow the farms providing data to supplement missing information and, where necessary, to specify the entries for MAUS.

As part of a pilot project, a technical solution was developed with one of the Swiss providers and is currently being implemented. This has shown that, in addition to a precise definition of requirements, constant and lively dialogue is important. A comprehensive data set that exemplifies how operating data must arrive at MAUS not only helps with final testing, but also with understanding the implementation.

In the near future, other interested FMIS are to supplement their platforms so that data can be supplied to MAUS. In the collaboration between Agroscope and the interested providers, both parties will benefit from the preliminary work and the findings of the pilot project.

How to cite: Blaser, S., Baumgartner, S., Schneuwly, J., and Gilgen, A.: Integration of data from agricultural practice into the Swiss agri-environmental monitoring project MAUS, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3443, https://doi.org/10.5194/egusphere-egu24-3443, 2024.

EGU24-5171 | ECS | Posters on site | BG8.9

Mapping the nationwide crop phenology stages in Saudi Arabia using machine learning and Sentinel-2 NDVI time series 

Ting Li, Oliver Miguel Lopez Valencia, Kasper Johansen, and Matthew Francis McCabe

Vegetation phenology, encompassing critical events like leaf emergence and maturity, serves as an important indicator of adaptive plant responses to environmental factors. In the context of Saudi Arabia, existing crop phenology retrieval methods encounter several challenges related to local farm management operations. These can include unstable crop calendars with planting and harvesting at any time throughout the year, uncertainty in sub-field management with independent control of areas within a center-pivot field, and diverse crop rotations between fodder and non-fodder crops. To address these challenges, we present an innovative framework utilizing machine learning and Sentinel-2 NDVI time series data for mapping phenology stages of key crops at a national scale. The framework is composed of three modules that are implemented step-wise, including: (1) a within-field dynamic clustering module (termed WithinFDy) that monitors fields for potential subdivision based on pixel-level NDVI temporal dynamics; (2) a phenology estimation module (termed PhenoEst) that segments NDVI time series into growing seasons and extracts essential phenology stages (e.g., planting and harvesting dates) for each season; and (3) a crop type discrimination module (termed CropDis) that utilizes extracted phenology information as input features to discriminate between different crop types. Evaluated on 1,000 randomly selected fields in northern Saudi Arabia, our framework achieved overall accuracies of 93.38%, 96.40%, and 94.39% for WithinFDy, PhenoEst, and CropDis modules, respectively. When applied nationwide in 2020, the framework revealed valuable insights. In terms of field management, 21.8% of the fields were divided into two distinct subfields, featuring different planting and harvesting dates - and sometimes crop type, while 73.2% showed consistent practices across the entire field. For seasonal dynamics, 53.4%, 36.3%, and 8.7% of fields supported crops for one, two, and three seasons annually, respectively. Main planting and harvesting activities occurred during winter seasons (November to February), with another peak observed in June. Approximately 30% of fields were under production for 5 to 6 months, and 15.7% were under production year-round. The dominant crop types in 2020 were fodder crops (e.g. alfalfa and Rhodes grass), followed by winter crops like winter wheat. Our methodology represents a substantial advancement over previous approaches, expanding applicability beyond crops with regular growth patterns. The results not only enrich agricultural datasets in Saudi Arabia but also hold promise for enhancing food and water security studies globally.

How to cite: Li, T., Lopez Valencia, O. M., Johansen, K., and McCabe, M. F.: Mapping the nationwide crop phenology stages in Saudi Arabia using machine learning and Sentinel-2 NDVI time series, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5171, https://doi.org/10.5194/egusphere-egu24-5171, 2024.

EGU24-5448 | Posters on site | BG8.9

Improving high-resolution spatial information on agricultural land use management in Europe for economic land use modelling and the assessment of policy impacts 

Linda See, Orysia Yashchun, Zoriana Romanchuk, Juraj Balkovič, Rastislav Skalsky, Žiga Malek, Dmitry Schepaschenko, Andre Deppermann, Tamás Kriztin, and Petr Havlík

There is currently a lack of high-resolution pan-European information on land use management, especially in terms of how intensively and extensively cropland and grassland are managed. This is partly due to the lack of ground-based information, which is needed to downscale these types of management practices (some of which are captured in different types of agricultural censuses and surveys) as well as the inability of remote sensing to capture different kinds of land use. This type of information is needed for economic land use modelling and for assessing policy impacts, such as the latest reforms from the Common Agricultural Policy (CAP) and other European Union (EU) Green Deal targets. These types of analyses are undertaken using economic land use models such as GLOBIOM and CAPRI, which is one of the main aims of the Horizon Europe funded LAMASUS project (https://www.lamasus.eu/).  

This presentation will provide an overview of the ongoing developments in creating high-resolution spatially explicit layers on agricultural and grassland management for Europe to support the LAMASUS project. The proposed cropland and grassland management classes will be outlined along with the methodology for how they have been implemented using existing data layers from remote sensing, statistical data from Eurostat, the Joint Research Centre of the EU, agricultural ministries, and other sources. One of the key challenges is ensuring that the high-resolution data matches official statistics at the national (and NUTS2 level where available) so that they can be used by the economic land use models in LAMASUS. A method will be presented for how this is achieved using priors in the form of integrated layers of cropland and grassland probability created from existing high-resolution remotely sensed input layers.

 

How to cite: See, L., Yashchun, O., Romanchuk, Z., Balkovič, J., Skalsky, R., Malek, Ž., Schepaschenko, D., Deppermann, A., Kriztin, T., and Havlík, P.: Improving high-resolution spatial information on agricultural land use management in Europe for economic land use modelling and the assessment of policy impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5448, https://doi.org/10.5194/egusphere-egu24-5448, 2024.

EGU24-6031 | Posters on site | BG8.9

Country-wide Cross-Year Crop Mapping from Optical Satellite Image Time Series 

Mehmet Ozgur Turkoglu, Helge Aasen, Konrad Schindler, and Jan Dirk Wegner

Previous works on vegetation mapping from optical satellite images use training and test datasets within the same year. We think that from a practical perspective, this experimental setting is not realistic due to (i) crop growth changes from year to year (also like from region to region), therefore test assessment does not fully reflect real-world cases and (ii) obviously it is not possible to apply the algorithm current year if it is trained with current year data. Thus a cross-year experimental setting should be de-facto for this line of research then we can readily apply developed algorithms in real-world applications. In this work, we evaluate a state-of-the-art crop classification method from optical satellite (Sentinel-2) image time series data - a hierarchical multi-stage deep learning method, i.e. ms-convSTAR which we introduced in [1] - in a cross-year experimental setting. The deep learning model is trained with the entire 2021 crop dataset in Switzerland and during test time it is applied to the 2022 crop dataset. Our results show that our method performs reasonably well in this experimental setting achieving ~83% accuracy at the pixel level. 

References

[1] Turkoglu, M. O., D'Aronco, S., Perich, G., Liebisch, F., Streit, C., Schindler, K., & Wegner, J. D. (2021). Crop mapping from image time series: Deep learning with multi-scale label hierarchies. Remote Sensing of Environment, 264, 112603.

How to cite: Turkoglu, M. O., Aasen, H., Schindler, K., and Wegner, J. D.: Country-wide Cross-Year Crop Mapping from Optical Satellite Image Time Series, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6031, https://doi.org/10.5194/egusphere-egu24-6031, 2024.

EGU24-7035 | Orals | BG8.9 | Highlight

Assessment of wetland ecosystem services associated with changing climate and agricultural wetland drainage in a major food producing region 

Colin Whitfield, Emily Cavaliere, Helen Baulch, Robert Clark, Chris Spence, Kevin Shook, John Pomeroy, and Zhihua He

Agricultural regions worldwide face the dual challenge of producing food for a growing world population while simultaneously reducing the industry’s environmental footprint. The prairie region of western Canada, where more than 40 million ha are used as cropland or pasture, is one of the world’s major food producing regions. This complex landscape provides agroecosystem services associated with these agricultural lands and their millions of depressional wetlands. As a cold region, and one with a highly variable climate which is undergoing strong climate change, agricultural practices continue to evolve. One widely used tool for adaptation to wet periods and to maximize arable land area is to drain wetlands; however, a tradeoff exists between draining wetlands to support expansion of cropland, and conserving wetlands to maintain their valuable ecosystem services. Wetland drainage decisions are often made without identifying impacts to the services these systems provide.

We address this gap using a novel assessment to quantify impacts to ecosystem services via wetland drainage in the Canadian prairie landscape, and explore how wetland ecosystem services may be impacted by future climate. Quantifying response of a suite of indicators (median annual flows, total phosphorus export, riparian habitat, dabbling ducks, wetland-associated birds, carbon sequestration) to wetland drainage demonstrated that all respond strongly to the loss of depressional wetlands, but sensitivity varies among the indicators. Median annual flows and phosphorus export respond more strongly than longer return period flows, potentially tripling in magnitude with high levels of wetland loss. Dabbling ducks and wetland-associated bird abundances are even more sensitive, with abundances predicted to decrease by half with loss of as little as 20% of wetland area. As a relatively unique region, where inundated wetland area is highly dynamic both interannually as the system alternates between dry and wet phases, and intra-annually (across seasons), wetland ecosystem services response to climate change is more nuanced. In the Canadian prairie, there appears to be a delicate balance between future warming and changes in precipitation amount that could yield either increases or decreases in wetland area, with wetland ecosystem services anticipated to change accordingly. Our results illustrate the sensitivity of wetland ecosystem services to agroecosystem management and climate change in a major food producing region, highlighting the need to consider the tradeoff between loss of these services and benefits of agricultural expansion. Under a drier future climate, fewer remaining wetlands may both enhance the value of wetland-associated ecosystem services, and temper the demand for wetland drainage.

 

How to cite: Whitfield, C., Cavaliere, E., Baulch, H., Clark, R., Spence, C., Shook, K., Pomeroy, J., and He, Z.: Assessment of wetland ecosystem services associated with changing climate and agricultural wetland drainage in a major food producing region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7035, https://doi.org/10.5194/egusphere-egu24-7035, 2024.

EGU24-7646 | ECS | Posters on site | BG8.9

Estimation of annual grassland yields with Sentinel-2 time series 

Sophie Reinermann, Anne Schucknecht, Ursula Gessner, Sarah Asam, Ralf Kiese, and Claudia Kuenzer

Grassland ecosystems shape the landscape in large parts of Germany and provide numerous services that are relevant for the carbon cycle, water quality and biodiversity, apart from being the main source of fodder for the dairy and meat industry. Annual yields between grasslands vary strongly because their productivity depends on the management and environmental conditions. Information on grassland yields are not freely and extensively available in Germany but would be relevant for comprehensive assessments of grassland ecosystem services including the impact of extreme events on yields. With satellite remote sensing, grassland productivity and yields can be extensively and multi-temporally estimated. Within our project (SUSALPS, https://www.susalps.de/en/), grassland yields are estimated in a grassland-dominated area in southern Germany using ground-truth measurements of above-ground biomass and Sentinel-2 time series data. Field data was collected on 12 differently used grassland parcels in the region in 2019-2021. We aim to overcome limitations of previous research – caused by the heterogenous nature of grasslands due to varying use intensities in Germany – by including management information and a large gradient of field samples trough multiple measurements throughout the vegetation growth period into the modelling. We tested empirical model based on the field and accompanying Sentinel-2 data (n=74) to estimate grassland biomass. The best model was applied to all available Sentinel-2 scenes in the region in 2019. Random Forest and Artificial Neural Network models showed the highest accuracy (R²cv = 0.7). A novel input feature was the mowing date which is available as 6-year dataset (Reinermann et al. 2022 & 2023). Next, the multi-temporal biomass estimations are aggregated to annual yield estimates to enable spatially discrete and multi-annual yields are estimated and compared (2018-2023). First results show that the inclusion of mowing date information supports the reliable estimation of grassland yields and its assessment on fine spatial scale substantially. In the future, the results are coupled with modelled plant biodiversity information to gain a complementary picture on grassland ecosystem services.

How to cite: Reinermann, S., Schucknecht, A., Gessner, U., Asam, S., Kiese, R., and Kuenzer, C.: Estimation of annual grassland yields with Sentinel-2 time series, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7646, https://doi.org/10.5194/egusphere-egu24-7646, 2024.

EGU24-9284 | ECS | Posters on site | BG8.9

An improved biodiversity index for FAO’s Tool of Agroecology Performance Evaluation (TAPE) 

Simon Baumgartner, Anina Gilgen, Rahel Felder, Felix Herzog, Philippe Jeanneret, Robin Séchaud, Stevan Paunovic, Dario Lucatoni, Remi Cluset, Anne Mottet, and Lutz Merbold

The "Tool for Agroecology Performance Evaluation" (TAPE) was developed under the coordination of the Food and Agriculture Organisation of the United Nations (FAO) to assess the sustainability performance of agroecosystems. The assessment is mainly based on a 2-3-hour farm interview, in which a wide variety of data is collected. The environmental dimension has so far been represented in TAPE by two simple indices: A soil index, which is based on a visual analysis of the soil, and a biodiversity index, which is primarily based on the Gini-Simpson index of crops grown and animals kept. While the TAPE biodiversity index is crucial, it does not yet take into account so-called unplanned biodiversity, i.e. the impact of on-farm management practices on wild species. We have therefore expanded TAPE to include this aspect.

Direct surveys of wildlife biodiversity in the field were not possible in TAPE, as this would have far exceeded the time required for data collection. Consequently, we based the newly developed biodiversity index on the indirect European BioBio method. The new index consists of ten indicators, which can take values between 0 and 100% and be aggregated to form the overall index. Examples of these indicators are field size, nitrogen application or stocking density. The new index was developed and tested on selected Swiss farms, where the comparison with a much more comprehensive and time-consuming method showed a positive correlation (r = 0.56, p-value = 0.009).

The new index has so far been used in Switzerland (21 farms) and in Kenya (103 farms). In Switzerland, the field size and land use change indicators performed best (values > 75%), while the indicators tree habitat, nitrogen application, field operations and grazing intensity performed poorly (values > 50%). In Kenya, the field size, land use change, pesticide and field operations indicators reached values above 75%, while the tree habitat, grazing intensity and semi-natural habitat indicators had values clearly below 50%.

How to cite: Baumgartner, S., Gilgen, A., Felder, R., Herzog, F., Jeanneret, P., Séchaud, R., Paunovic, S., Lucatoni, D., Cluset, R., Mottet, A., and Merbold, L.: An improved biodiversity index for FAO’s Tool of Agroecology Performance Evaluation (TAPE), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9284, https://doi.org/10.5194/egusphere-egu24-9284, 2024.

EGU24-9951 | ECS | Posters on site | BG8.9

A hybrid framework for improved crop mapping over a large scale by combining pixel-based and object-based approaches 

Yuanyuan Di, Jinwei Dong, Ping Fu, and Stuart Marsh

Remote sensing technology presents unique possibilities for monitoring agricultural systems, providing accurate information like crop type distribution, crop planting area, crop rotation, etc. Extracted from remote sensing imagery, previous efforts generally produce crop information based on pixel-based classification strategy without considering spatial context of objects. Further incorporation of object-based image analysis in crop type mapping could improve mapping accuracy and reduce disturbance caused by uncertainties caused by pixel-based methods. Here we aim to combine the advantages of pixel-based and object-based approaches for further improving crop type maps over Northeast China based on Sentinel-2 imagery, simple non-iterative clustering (SNIC), random forest classifier and Google Earth Engine platform. The results showed in the majority of cropland, object-based mapping results had higher accuracies and reduced obvious errors at parcel level. Overall accuracies improved by 0.5% and the Kappa coefficient improved by 9% in Sanjiang Plain. However, soybean and maize intercropping with small parcels could be ignored in object-based methods when clustering objects. Therefore, an integration of pixel and object-based approaches was adopted considering different landscapes and patch areas to generate an unprecedentedly accurate crop type map in Northeast China.

How to cite: Di, Y., Dong, J., Fu, P., and Marsh, S.: A hybrid framework for improved crop mapping over a large scale by combining pixel-based and object-based approaches, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9951, https://doi.org/10.5194/egusphere-egu24-9951, 2024.

EGU24-13479 | ECS | Orals | BG8.9 | Highlight

Spatially-explicit greenhouse gas footprints of agricultural commodities from around the world 

Chaidir Arsyan Adlan, Birka Wicke, Steef V. Hanssen, and Carlijn Hendriks

Agriculture and its land use are associated with 22% of global annual anthropogenic greenhouse gas (GHG) emissions [1]. Reducing these emissions requires insight into how much emissions are caused by specific agricultural commodities and where they occur. Commodity-specific GHG footprints are a useful tool in this regard as they enable producers to determine the emission intensity and environmental impact of their products [2]-[3]. Further, they can help identify emission reduction strategies and region-specific mitigation efforts [4]-[6].

Spatially-explicit GHG footprints are particularly useful since they show the geographic distribution of commodities’ emission intensity and allow for the comparison across countries [7]. Several past studies have produced crop-specific footprints but considered emissions solely from land use change and did not include emissions from agricultural practices [8]-[11]. Attribution was mostly conducted at aggregate level such as country and region level [16],[17]. Those studies that employed spatially-explicit attribution methods are characterized by limited geographical coverage [14] and a limited selection of crops [15]. Studies also applied largely different methods for attributing emissions to crops, making comparison across studies not possible. 

The current study aims at filling in this research gap by improving data resolution and the methodology for attributing dynamic land-use emissions to specific crops. We derive global spatially-explicit GHG emission footprints for 161 agricultural crops over the period of 1970 to 2021 at 15 arcmin resolution. We do so by quantifying spatially-explicit land-use emissions related to agriculture and then attributing them to specific agricultural commodities (Fig1). The analysis is conducted using the LUH2 dataset on land use dynamics over time [16] and IMAGE-LPJmL 3.2 for carbon stock data [17]. IMAGE-LPJmL is a dynamic global vegetation model that simulates vegetation dynamics and distribution based on carbon cycle and crop growth model [18], [19]. This allows leveraging advanced data in terms of dynamic, annual, and spatially specific carbon stocks (Tier-3), rather than constant and/or national level carbon stock data (Tier-1) as generally used in the literature.

This study also compares three different emission attribution methods (AM) (Fig2). AM1 uses an annual accounting period, attributing emissions to the land use change committed in the same year. AM2 uses a larger time step and attributes the emissions only to the land use type at the end of the accounting period. These two methods are the two most employed methods in carbon accounting studies. We also propose an alternative approach that reflects the dynamics of land use (AM3); we attribute the emissions based on occupation year of each land use type in the accounting period.

The expected results of this study are crop-specific GHG footprints in terms of land use emissions per production area (tCO2eq/ha) and per crop yield (tCO2eq/ton) at the grid level as well as means and variations per crop and country. Also, variations as a result of different AMs will be presented and its implications for research and application in e.g. corporate emission reporting and target setting will be discussed. 

Fig1

Fig2

How to cite: Adlan, C. A., Wicke, B., Hanssen, S. V., and Hendriks, C.: Spatially-explicit greenhouse gas footprints of agricultural commodities from around the world, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13479, https://doi.org/10.5194/egusphere-egu24-13479, 2024.

EGU24-13714 | Orals | BG8.9 | Highlight

Mapping, Attribution, and Environmental Effects of Woody Plant Encroachment in Grasslands under Climate Change and Human Activities 

Jie Wang, Chuchen Chang, Xu Wang, Jilin Yang, and Xiangming Xiao

Woody plant encroachment (WPE) into grasslands has been occurring globally and may be accelerated by climate change and human activities in the future. There are limited studies to document this ecological process and hamper our understanding to make sustainable management approaches for grassland conservation.  Here, we improved our previous studies on woody plant encroachment in the grasslands of Oklahoma, USA.  This study (1) summarized the detection of woody plant encroachment into grasslands over the typical regions in global through PALSAR, Sentinel-1, Sentinel-2, and Landsat images; (2) examined the drivers of woody plant encroachment into grasslands at local and global scales; and (3) developed approaches to quantify the effects of woody plant encroachment into grasslands on carbon, water, and local land surface temperature. The results provide some insights to understand the process and assocaited drivers of woody plant encroachment during the last decades and the roles on carbon and water cycles and the local environment.

How to cite: Wang, J., Chang, C., Wang, X., Yang, J., and Xiao, X.: Mapping, Attribution, and Environmental Effects of Woody Plant Encroachment in Grasslands under Climate Change and Human Activities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13714, https://doi.org/10.5194/egusphere-egu24-13714, 2024.

EGU24-14243 | Posters virtual | BG8.9

Makara: Navigating Agricultural Challenges through Digital Innovation 

Ramesh Guntha, Aiswarya Aravindakshan, Soham Adla, Maya Presannakumar, Mario Alberto Ponce Pacheco, and Saket Pande

Modern-day agriculture presents numerous challenges for small rural farmers, including labor issues, fluctuating costs, unpredictable weather, and the complexities of managing fertilizers, pesticides, and market dynamics. These challenges often hinder farmers from making timely decisions that could maximize their revenue and minimize costs.

The Makara app stands out as a groundbreaking tool in agricultural management, providing a digital platform meticulously designed to meet the diverse needs of farming. It enables farmers to create individual accounts and input detailed information about their land, including soil type, soil health parameters, water sources (such as borewells, rivers, or pipelines), and preferred irrigation methods. The app's versatility allows farmers to manage multiple lands and configure various crops for each, supporting both mixed cropping and multi-cropping systems. Additionally, farmers can adjust crop configurations annually and seasonally, offering unparalleled flexibility in digital farming management.

Makara's interface is exceptionally adaptable and capable of digitizing and tracking any farming setup. Beyond just planning, the app excels in financial management, assisting farmers in budgeting and recording expenses. This includes costs for seeds, fertilizers, and various labor activities like irrigation, weeding, land preparation, applying fertilizers and pesticides, harvesting, transportation, and storage. These financial features are detailed at the crop level for each season and year, providing farmers with a comprehensive view of their agricultural expenses and aiding in more informed financial decision-making.

A standout feature of Makara is its day-to-day advisory service, which provides guidance based on best practices, and insights into planting seasons, crop varieties, and growth stages. The app's recommendations on fertilizers and pesticides aim to promote sustainable farming and maximize yields. Additionally, Makara assists in activity planning and journaling, enabling farmers to maintain systematic records of their farming activities. The app emphasizes budgeting, cost and revenue management, and farm resource optimization, positioning itself as an all-encompassing agricultural tool.

The app's risk prediction module offers farmers valuable insights into expected crop yields for upcoming seasons, allowing them to estimate the likelihood of achieving specific yield targets and the corresponding potential income and profits. This feature is complemented by a historical market price database, enabling farmers to make informed decisions based on predicted yields and market trends.

Makara is crafted for user-friendliness and accessibility, featuring a multilingual interface that not only displays content but also provides audio readouts to farmers in their native languages. Mindful of the connectivity issues often encountered in rural settings, the app is equipped with an offline mode. This ensures uninterrupted operation and access to previously stored data, even in the absence of network connectivity, making it a reliable tool for farmers regardless of their location.

This paper introduces the Makara app, detailing its main functionalities, deployment strategies, and the considerations behind its design choices. We also present an analysis of the app's deployment and usage, highlighting its impact on alleviating the cognitive burden faced by farmers in making crucial decisions that significantly affect their costs and revenues.

How to cite: Guntha, R., Aravindakshan, A., Adla, S., Presannakumar, M., Alberto Ponce Pacheco, M., and Pande, S.: Makara: Navigating Agricultural Challenges through Digital Innovation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14243, https://doi.org/10.5194/egusphere-egu24-14243, 2024.

EGU24-15266 | Orals | BG8.9 | Highlight

Towards Live, Nation Wide, Farm-Level  Crop Monitoring  

Ishan Deshpande, Amandeep Kaur Reehal, Gaurav Singh, Chandan Nath, Renu Singh, and Alok Talekar

Accurate and timely information about expected crop production is crucial for various applications including agricultural monitoring, policy making, and food security assessment. Policy makers can use near-real time crop maps to better determine crop support prices, storage infrastructure, and imports. In the context of India, absence of farm-level crop maps r the government to work with aggregate statistics based on manual surveys, and therefore are fundamentally limited in scale and accuracy. Surveys over large regions such as entire states or countries are slow and provide information only after large delays. Indian farms also go through up to three crop rotations a year necessitating continual monitoring. We put forward a nation-wide, farm-level, weekly agricultural monitoring and event detection model for the study area of India. Our model leverages remote sensing and machine learning to build a crop map that allows us to accurately monitor individual farms across large areas. 

We utilize the rich spectral and temporal information provided by Sentinel-2 satellite to provide near-real time crop monitoring, including sowing, crop type, and harvesting information. The predictions are done on an individual farm level with farm boundaries coming from a field segmentation model. Making predictions on a farm level scale helps getting more accurate yield estimates and allows monitoring individual fields for credit, insurance, resource allocation, etc. Currently, the model is able to identify major winter crops with an accuracy of up to 80% as early as 2 months after sowing. Equipped with the ability to provide weekly sowing and harvesting information makes the model near-real time for agricultural purposes. We also demonstrate the scalability of the model by showing results pan-India, across several diverse agro climatic zones. The model successfully generalizes to many unseen regions without requiring regional data. Using satellite data to provide accurate and timely crop cover information has the potential of saving millions of dollars spent by the government on manual surveys.

How to cite: Deshpande, I., Reehal, A. K., Singh, G., Nath, C., Singh, R., and Talekar, A.: Towards Live, Nation Wide, Farm-Level  Crop Monitoring , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15266, https://doi.org/10.5194/egusphere-egu24-15266, 2024.

EGU24-15697 | Posters on site | BG8.9

Monitoring Changes In Agricultural Field Boundaries Using Spatiotemporal Remote Sensing Data 

Nikita Saxena, Abigail Annkah, Ishan Deshpande, Alex Wilson, and Alok Talekar

In the domain of precision agriculture, land-use planning, and resource management, the precise delineation of field boundaries is pivotal for informed decision-making. The dynamic nature of agricultural landscapes, particularly in smallholder farming, introduces seasonal changes that pose challenges to accurately identify and update field boundaries. The conventional approach of relying on high-resolution imagery for this purpose proves to be economically impractical on a seasonal basis. We propose a framework that utilizes a spatiotemporal series of medium-resolution public imagery (e.g., Sentinel-2) in conjunction with an outdated high-resolution image as a reference for super-resolution reconstruction. The developed methodology incorporates super-resolution techniques to enhance the spatial resolution while simultaneously performing semantic segmentation at the higher resolution. We evaluate the proposed model's performance in predicting seasonal field boundaries at a pan-India level. The validity of these findings is established through assessment by a team of human annotators.

Our approach aims to offer a scalable spatiotemporal solution for accurate field boundary identification at a national level by combining information from different satellites at different resolutions.

How to cite: Saxena, N., Annkah, A., Deshpande, I., Wilson, A., and Talekar, A.: Monitoring Changes In Agricultural Field Boundaries Using Spatiotemporal Remote Sensing Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15697, https://doi.org/10.5194/egusphere-egu24-15697, 2024.

EGU24-15816 | Posters on site | BG8.9 | Highlight

Applying the Pesticide Load Index to characterize ecotoxicological impact from pesticide use in the EU 

Rui Catarino, Francesco Galimberti, Stephanie Bopp, Thomas Fellmann, Ana Klinnert, Michael Olvedy, Maria Luisa Paracchini, Alberto Pistocchi, Xavier Rotllan-Puig, Jean-Michel Terres, Marijn Van Der Velde, and Raphael d'Andrimont

Improving the sustainability of agriculture requires an advanced assessment of the ecological impacts of pesticides at both policy and scientific levels. This can be achieved by integrating ecological considerations into the assessments of plant protection products beyond plot or experimental sites. Among plant protection products, pesticides are often the most harmful and toxic due to the chemical properties of their active substances (AS), which can range from non- to extremely toxic depending on the organism affected. Our study applies the Pesticide Load Index (PLI), as applied in Denmark and in the United Kingdom , to quantify pesticide risks to environmental health and biodiversity across the European Union. The PLI is defined as the sum of the application rate (AR) for each applied AS (k) divided by the toxicity (TOX) for a number of non-target taxa such as birds, mammals, fish, algae and agricultural beneficial insects like bees and natural enemies of pests, using the formula: PLI = Σ (ARk / TOXk,i).

Our methodology bridges the gap between ecological health and pesticide risk assessment using three extensive data sets (Figure 1). The first includes EU-wide estimations of AS emissions, as geospatial layers at 1km resolution, representing the most extensive data collection available for the entire European Union. The second dataset provides unparalleled granularity in AS use, capturing field-level information across France for the year 2018, including details on crop type distribution. The third dataset, sourced from the Pesticide Properties DataBase, assesses the ecological impacts of pesticide use by linking usage to ecotoxicological endpoints.

Figure 1: Overview of the methodology for the Pesticide Load Index (PLI) Study. 

By integrating acute toxicity, chronic toxicity, and environmental fate, our approach moves towards a thorough understanding of pesticide impacts. Acute toxicity, indicative of short-term exposure, highlights immediate and potentially severe effects, while chronic toxicity addresses the long-term consequences of prolonged and continuous exposure. The environmental fate sheds light on the pesticides' behaviour and transformation in the environment, considering their distribution, degradation, accumulation, and transport across air, water, and soil.

The outcomes of this study provide a new perspective on pesticide use within the EU. The highly granular nature of the PLI maps makes them key tools for identifying areas with high ecotoxic levels, and therefore informing where additional risk mitigation measures are necessary. Detailed analyses are done by i) identifying predicted hotspots of pesticide use across the EU, ii) analysing variations in bio-climatic regions, and iii) breaking down the results by crop type and region. The role of this approach in monitoring the progress towards the European Union Farm to Fork and Biodiversity strategies targets is therefore clear, particularly in relation to the ambitious target of reducing pesticide use and toxicity by 50% by 2030. 

Our framework provides essential ecological insights for biodiversity conservation and ecosystem preservation, providing policy-makers with spatially explicit data for better-tailored strategies. Additionally, by enabling comparisons between crops, regions, and EU Member States it can contribute as to developing protective, realistic, and scientifically sound regulatory frameworks.  

How to cite: Catarino, R., Galimberti, F., Bopp, S., Fellmann, T., Klinnert, A., Olvedy, M., Paracchini, M. L., Pistocchi, A., Rotllan-Puig, X., Terres, J.-M., Van Der Velde, M., and d'Andrimont, R.: Applying the Pesticide Load Index to characterize ecotoxicological impact from pesticide use in the EU, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15816, https://doi.org/10.5194/egusphere-egu24-15816, 2024.

EGU24-16407 | Posters virtual | BG8.9

EMBAL - European Monitoring of Biodiversity in Agricultural Landscapes 

Luca Kleinewillinghöfer, Clemens Baier, Carsten Haub, Dirk Lindemann, Rainer Oppermann, Lars Roggon, Laura Sutcliffe, and Oliver Buck

The 'European Monitoring of Biodiversity in Agricultural Landscapes' (EMBAL) is a monitoring initiative initiated by the European Commission that gathers information on the state of biodiversity in agricultural landscapes across EU member states. Developed within the EU Pollinator Monitoring Framework, EMBAL is a standardized and sample-based in-situ survey of 500x500m landscape sections (plots).

EMBAL provides comprehensive data, including general information on land use and land cover at parcel level, information about landscape elements, and specific vegetation data on a transect level in grassland and arable habitats. Both the methodology and the sampling frame are harmonized with LUCAS (Land Use and Coverage Area frame Survey).

Following a successful pilot in 2020, EMBAL was applied in all 27 EU member states in 2022 and 2023, surveying a total of 3,000 selected plots in both years. This extensive rollout served to gather harmonised baseline data on biodiversity across EU27 and provided a comprehensive field test of the EMBAL methodology across different European landscapes.

In this contribution, we offer an overview of the EMBAL 2022 and 2023 rollout, the EMBAL survey methods and parameters and provide an outlook on the results.

How to cite: Kleinewillinghöfer, L., Baier, C., Haub, C., Lindemann, D., Oppermann, R., Roggon, L., Sutcliffe, L., and Buck, O.: EMBAL - European Monitoring of Biodiversity in Agricultural Landscapes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16407, https://doi.org/10.5194/egusphere-egu24-16407, 2024.

EGU24-16609 | Orals | BG8.9

Evaluation of pesticide use restrictions near urban areas in the European Union 

Francesco Galimberti, Rui Catarino, Thomas Fellmann, Pietro Florio, Pieter Kempeneers, Ana Klinnert, Michael Olvedy, Alberto Pistocchi, and Raphael D'Andrimont

The European Commission’s strategies under the European Green Deal aim at reducing the risks to human health and the environment from pesticide use. One of the proposed policies to achieve that goal is a restriction in use of pesticides within and near urban areas. 
In this study, we aim to estimate the impact of a full pesticide use restriction on crops near urban areas at the EU scale, by combining available EU data on urban settlements and crops. We will achieve this by utilizing spatial layers from the Joint Research Centre (JRC), including the Global Human Settlement Layer (GHSL) and the EUCROPMAP 2018 integrated with information from the Corine Land Cover (CLC) 2018.
Using various buffer distances from urban areas, the study seeks to quantify the agricultural area and crop types that will be impacted by the full restriction in use. The results will also provide insights into the percentage of treated vs. non-treated crops present in these buffer zones, highlighting country and regional differences. The economic importance of crops, together with reduced crop yields can be explored as well. Additionally, reduction in health risk to residents can be estimated from information on crop-specific intensities in pesticide use.

How to cite: Galimberti, F., Catarino, R., Fellmann, T., Florio, P., Kempeneers, P., Klinnert, A., Olvedy, M., Pistocchi, A., and D'Andrimont, R.: Evaluation of pesticide use restrictions near urban areas in the European Union, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16609, https://doi.org/10.5194/egusphere-egu24-16609, 2024.

EGU24-16882 | Posters on site | BG8.9 | Highlight

Quantitative Measurement of Landscape Features in EU Agriculture: A Novel Indicator Approach  

Raphaël d'Andrimont, Jon Skøien, Talie Musavi, Momtchil Iordanov, Javier Gallego, Davide De Marchi, Renate Koeble, Irene Guerrero, Ana Montero-Castaño, Jean-Michel Terres, and Bálint Czúcz

The conservation and creation of landscape features is recognised as a key conservation tool to halt the loss of agricultural biodiversity in European farmland.

This study introduces a new indicator to quantify landscape features in EU agricultural land, based on the LUCAS Landscape Feature survey. We developed a comprehensive methodology to measure and categorise landscape features, distinguishing Woody, Grassy, Wet, and Stony LF types. Our approach gives a robust and reproducible estimate of the indicator at the EU Member State and possibly regional levels, based on a reliable and statistically representative sample of landscape features.

The methodology combines office-based photo-interpretation with field surveys collecting 3.8 millions field points, ensuring accuracy in determining the presence and type of landscape features within agricultural contexts. Together with information on biodiversity and ecosystem services, it will play a crucial role in evaluating the performance of major policies related to biodiversity conservation in agricultural lands, aligning with the Common Agricultural Policy and the EU Biodiversity Strategy for 2030. Besides, it will play a role in the assessment of natural based solutions for mitigating climate change effects, biodiversity loss and crop production (food) security.

Our findings reveal that, in 2022, landscape features covered 5.6% of EU agricultural land. Woody features were the most prevalent, followed by Grassy, Wet, and Stony features. The percentages of landscape features varied across EU Member States, with Malta and Cyprus exhibiting higher values.

The novel indicator developed is based on a comprehensive and reproducible method for quantifying these features, providing essential insights for policy and decision-making in sustainable agriculture.

How to cite: d'Andrimont, R., Skøien, J., Musavi, T., Iordanov, M., Gallego, J., De Marchi, D., Koeble, R., Guerrero, I., Montero-Castaño, A., Terres, J.-M., and Czúcz, B.: Quantitative Measurement of Landscape Features in EU Agriculture: A Novel Indicator Approach , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16882, https://doi.org/10.5194/egusphere-egu24-16882, 2024.

EGU24-17135 | ECS | Posters on site | BG8.9

Comparing crop calendars: phenology derived from Sentinel-2 data vs official data: The case of cereals in Andalusia. 

Miguel Angel García Pérez, Jose A. Caparros-Santiago, and Victor Rodriguez-Galiano

Obtaining specific field calendars for each crop is very useful information for farmers and public administration to understand and manage harvests. This information can be collected manually from each farm, but this approach is highly time and money consuming. It is possible to acquire it more efficiently using phenology estimates obtained through remote sensing. Common Agrarian Policy (CAP) and Geographical Information System of the Common Agrarian Policy (GISCAP) data were used to know the location of principal cereal plots in Andalusia, Spain. It included common wheat, durum wheat, triticale, oat, rye, barley, sorghum, maize and rice.  Several phenometrics from Sentinel-2 were obtained: start of the season (SOS), middle of the season (MOS), length of the season (LOS) and end of the season (EOS). This dataset was correlated and compared with sowing and harvesting data collected by the Spanish government.  The results showed a high correlation between SOS and sowing and between EOS and harvest for most of the studied crops.

Sowing for common wheat, durum wheat, triticale, oat, rye, and barley took place between October and December according to government calendars, while SOS generally started one month later, between November and January. However, in these crops, harvest and EOS occurred simultaneously, mostly in June. In the case of sorghum, maize and rice, which are summer cereals, their phenometrics differed from the others. Sowing and SOS for sorghum mostly occurred in April and March, and harvest and EOS in September and October, in typically at the same time. Maize sowing took place in March, SOS in April, and harvest and EOS in September. Finally, rice sowing occurred in May, SOS in June, harvest in October and EOS in November. This study shows that obtaining accurate crop calendars from Sentinel-2 phenological trajectories is feasible, providing valuable information for farmers and public administrations.

How to cite: García Pérez, M. A., Caparros-Santiago, J. A., and Rodriguez-Galiano, V.: Comparing crop calendars: phenology derived from Sentinel-2 data vs official data: The case of cereals in Andalusia., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17135, https://doi.org/10.5194/egusphere-egu24-17135, 2024.

EGU24-17997 | Posters on site | BG8.9

Optimized resolution of gridded data from European agricultural census 

Jon Olav Skøien, Nicolas Lampach, Helena Ramos, Rudolf Seljak, Renate Koeble, and Marijn van der Velde

The European agricultural census  in 2020 collected a large number of variables from the major share of all the farms within the European Union. There are many potential applications of such a data set, from direct estimates of agricultural indicators to use as input in more complex analytical models. However, the individual responses in the data set cannot be shared directly, as they are regarded as confidential information. Instead, the data must be aggregated to a level where individual responses cannot be identified, typically NUTS regions or grid cells. As a minimum, each aggregated value must be estimated from at least 10 farms (frequency rule). Additionally, a dominance rule requires an aggregated value to be treated as confidential if the 2 largest farms are responsible for more than 85% of the value within a grid cell.

Whereas such requirements are clear, there are many methods for creating grids that respect them. The distribution of data is usually not homogeneous, and different methods have varying effects on the result.  We will outline the advantages and drawbacks of certain methods and present the most promising one that involves grid cells of varying sizes. Whereas there are some examples of this method in the past, it will be the first time it is applied on a continental scale and high-resolution data set such as the European agricultural census data.

How to cite: Skøien, J. O., Lampach, N., Ramos, H., Seljak, R., Koeble, R., and van der Velde, M.: Optimized resolution of gridded data from European agricultural census, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17997, https://doi.org/10.5194/egusphere-egu24-17997, 2024.

EGU24-18505 | Posters on site | BG8.9

European maps of crop / livestock categories and N budget parameters (timeseries 2000 – 2018) based on disaggregated CAPRI model data 

Renate Koeble, Adrian Leip, Markus Kempen, Maria Bielza, Rui Catarino, Maria Luisa Paracchini, Linda See, and Marijn Van Der Velde

The agricultural sector holds the greatest reduction potential to limit adverse effects of reactive nitrogen in the environment. Assessing the negative impacts of excessive release of reactive nitrogen into the biosphere requires spatially explicit information to capture e.g. hot spots of nitrogen surplus, nitrogen use efficiency, the impact on sensitive ecosystems or on ground/drinking water quality.

The agricultural economic model CAPRI is one of the main tools applied by the European Commission for the ex-ante analysis of the impact of agricultural policies and agro-environmental legislation at regional level (NUTS2) in Europe. CAPRI builds on long-term time series of regional, national and international agricultural statistics (e.g. crop and livestock production, fertilizer use), market and trade data. Inputs (e.g. inorganic fertilizer) in CAPRI are explicitly linked to production which delivers the basis for connecting environmental indicators (e.g. nitrogen surplus) directly to individual activities.

To provide the link between the agro-economic model CAPRI and the impact assessment of nitrogen use in agriculture on the environment at higher spatial resolution, we developed a procedure to disaggregate CAPRI regional data and provide maps of nitrogen input/output, crop and livestock production for the time series 2000 – 2018 at the level of Farm Structure Units (FSU) for 26 EU member states and the UK. The FSU are built by the spatial intersection of a 10 x 10 km2 INSPIRE compliant grid, the CAPRI NUTS2 region borders and the soil mapping units of the Harmonized World Soil Data Base (FAO/IIASA/ISRIC/ISS-CAS/JRC, 2009), having a median area of 12 km2 (minimum 1 km2, maximum 100 km2).

The disaggregation procedure for 36 crop types and 18 livestock categories from the regional level to the FSU is driven by information from the gridded Farm Structure Survey (FSS, 2010) crop and livestock data at 10 x 10 km2 resolution, CORINE (2018) non-agricultural land cover shares, altitude and slope constraints for individual crops / crop classes derived from LUCAS survey data (https://ec.europa.eu/eurostat/web/lucas).

Nitrogen inputs from mineral fertilizer and manure are disaggregated from the regional level to the FSU following the crops’ requirements. N input from atmospheric deposition and N supply by biological fixation is taken into account at FSU level. N from mineralization of soil organic matter could not be taken into account due to lack of data. N losses from volatilization and surface run-off, N removal by harvest, N in crop residues complete the N flow data set in agricultural areas at FSU level.

How to cite: Koeble, R., Leip, A., Kempen, M., Bielza, M., Catarino, R., Paracchini, M. L., See, L., and Van Der Velde, M.: European maps of crop / livestock categories and N budget parameters (timeseries 2000 – 2018) based on disaggregated CAPRI model data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18505, https://doi.org/10.5194/egusphere-egu24-18505, 2024.

EGU24-19472 | Posters on site | BG8.9

Meta-analytic evidence on effective farming practices for climate change mitigation 

Simona Bosco, Andrea Schievano, Marta Pérez-Soba, Ana Montero-Castaño, Mathilde Chen, Giovanni Tamburini, Rui Catarino, Irene Guerrero, Maria Bielza, Vincenzo Angileri, Michael Assouline, Renate Koeble, Otho Mantegazza, Frank Dentener, Marijn Van der Velde, Maria Luisa Parracchini, Franz Weiss, Jean-Michel Terres, and David Makowski

In the context of climate change, high expectations have been put on the agricultural sector for reducing greenhouse gas (GHG) emissions and enhance carbon sequestration. Consequently, a large and growing number of studies have evaluated the efficacy of various agricultural practices for climate change mitigation. However, the scientific evidence is often heterogeneous and frequently contradictory, making it difficult to use to support policy decisions. Meta-analyses synthesise large data sets and have become the gold standard for providing scientific evidence to inform environmental and agricultural policies. However, a growing number of meta-analyses are now available on a specific topic, occasionally with conflicting conclusions, requiring a further level of synthesis to consolidate the findings.

We present the results of a systematic review of 693 published meta-analyses on the effect of farming practices on climate change mitigation. After a systematic search and review of the literature, we extracted data assessing the climate impacts of 34 farming practices and 123 comparisons of sub-practices with corresponding control practices, for a wide range of cropping and livestock systems around the world. From this dataset, we selected the farming practices that showed overall significantly positive effects on the reduction of GHG emission and/or on the increase of carbon sequestration. For cropland and grassland, we were able to identify a set of 35 mitigation sub-practices , including cover and catch crops, intercropping, leguminous crops, the use of enhanced efficiency fertilisers, soil amendment with lime and gypsum, different crop residue management techniques, water management practices, different conservation, restoration and management measures in grasslands, conservation and restoration of peatlands and wetlands, the conservation and creation of landscape features, as well as organic farming systems. For livestock, we identified seven effective mitigation practices, including livestock feeding techniques, manure land application techniques, manure storage techniques. A limited number meta-analyses reported the effect of a given practice on more than one GHG or on GHGs coupled with carbon sequestration together, limiting the exploration of interacting effects.

The systematic evidence map provides robust and encompassing literature based evidence on farming practices with established positive effect on climate change mitigation to support a wide community of inventory compilers, modellers and policymakers. Our review also identifies farming practices with remaining knowledge gaps and research priorities.

How to cite: Bosco, S., Schievano, A., Pérez-Soba, M., Montero-Castaño, A., Chen, M., Tamburini, G., Catarino, R., Guerrero, I., Bielza, M., Angileri, V., Assouline, M., Koeble, R., Mantegazza, O., Dentener, F., Van der Velde, M., Parracchini, M. L., Weiss, F., Terres, J.-M., and Makowski, D.: Meta-analytic evidence on effective farming practices for climate change mitigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19472, https://doi.org/10.5194/egusphere-egu24-19472, 2024.

EGU24-21429 | Orals | BG8.9 | Highlight

Assessing impacts of farming systems on biodiversity using predictive indicators: a gradient of complexity 

Christian Bockstaller, Emma Soulé, Bastien Dallaporta, and Clélia Sirami

Agriculture plays a major role in the erosion of biodiversity, which represents one of the exceeded planetary boundaries. In the quest for solution to mitigate impacts of farming systems on biodiversity, it is essential to have tools to assess these impacts. Besides a plethora of indicators using field measurement of abundance or/and species richness of one or several taxa, predictive indicators offer a compromise between feasibility and integration of processes. Such indicators do not require in situ measurements and enable linking the response of biodiversity to drivers like agricultural practices.

Here we review three examples of predictive indicators representing a gradient of complexity regarding the number of input variables on field practices and landscape structure, the number of output variables on biodiversity components, and the model structure. The three indicators are NIVA-Biodiversity, BioSyScan and I-BIO.

NIVA-Biodiversity assesses biodiversity at the landscape and regional level, assessing biodiversity through a global score, without any precision on taxonomic or functional components, based on the percentage of semi-natural habitats (SNH), field size and crop diversity. BioSyScan is calculated at field level and assesses the impacts of field management (e.g. tillage, fertilization, pesticides spraying) and landscape variables (e.g field size and SNH) on soil-dependent species and mobile species. Last, I-BIO considers direct impacts of cropping systems on five taxonomic groups (microorganisms, plants, soil invertebrates, flying invertebrates and vertebrates) and indirect impacts through trophic chains.  It includes more precise variables on field and landscape management than the two other indicators. The three indicators are based on mixed models using linguistic rules “if-then”. While I-BIO is based on the DEXi tool and remains totally qualitative, NIVA-Biodiversity and BioSyScan were designed using the CONTRA aggregation method integrating fuzzy subsets in the decision rules, to mitigate threshold effects and increase transparency. We will highlight the potential use of each indicator using case studies, discuss the pros and cons of each indicator, and present the research needs to ensure their scientific validity.

How to cite: Bockstaller, C., Soulé, E., Dallaporta, B., and Sirami, C.: Assessing impacts of farming systems on biodiversity using predictive indicators: a gradient of complexity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21429, https://doi.org/10.5194/egusphere-egu24-21429, 2024.

EGU24-21456 | Orals | BG8.9 | Highlight

An indicator to monitor farmland biodiversity in OECD countries 

Wendy Fjellstad and Ulrike Bayr

The OECD uses a wide range of agri-environmental indicators to monitor effects of the agricultural sector on the environment. However, the only indicator of farmland biodiversity is the farmland bird index, and this is not reported by all member states. Therefore, work is ongoing to design a more general indicator of farmland biodiversity that can be reported by all member states.

There are many challenges in creating an indicator that can be applied across all OECD countries. These countries have very diverse farming systems, land ownership, climate, biophysical conditions, and species pools. In addition, there are big differences in the type and amount of data available with which to calculate an indicator. Some countries already have monitoring programmes, tailored to their specific national needs and priorities. It may be challenging to harmonize reporting across countries, when data are collected in different ways and from different sources.

As a first step, the OECD published in 2023 guidelines for the development of an OECD farmland habitat biodiversity indicator (https://doi.org/10.1787/09d45d55-en). The aim is to calculate an indicator based on all agricultural habitats within a country, both those of high nature value, but also the ordinary and those that are currently of very low value.

In 2024, several countries are testing calculation of the indicator using national data. This presentation will describe the proposed indicator and share experiences from work to calculate the indicator for Norway.

How to cite: Fjellstad, W. and Bayr, U.: An indicator to monitor farmland biodiversity in OECD countries, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21456, https://doi.org/10.5194/egusphere-egu24-21456, 2024.

Based on the background of climate change and rapid population & land urbanization, we developed the theoretical hypothesis and questions. As we know, urban usually have good education, hospital and housing, so many rural people flow to urban and indirectly take away industry and property. So rural communities face many challenges, such as less people, land, industry and property at least. For climate change, challenges from flooding, drought, heat wave, lower temperature, and frost timing. And opportunities maybe from Increasing and northward accumulated annual temperature (AAT10), and lengthen the growing season. For urbanization, challenges from abandonment, and less cropping frequency. And opportunities maybe from well-facilitated farmland, land unified management, and intelligent agriculture. Rural revitalization and urban-rural integration are two good measures for rural development policy not only in China but in many global counties. Yet, how to catch the rural people and agro-workers' eye, and improve the food supply ability are important questions. We will show some recent study results about geo-spatial change of croplands and its impacts on farming developments in China over the past two decades in this congress.

How to cite: Liu, Z.: Potential impacts of cropland dynamics on farming developments in China by analyzing a fused crop production data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22310, https://doi.org/10.5194/egusphere-egu24-22310, 2024.

EGU24-22312 | Posters on site | BG8.9

Identify the spatial-temporal pattern of the increased Cultivated land and its vulnerability in Northeast China from 2000 to 2020  

Jieyong Wang, Zhengjia Liu, Zehong Li, and Xiaoyong Liao

Ensuring compliance with China's “1.8 billion mu”(120 million hectares) cultivated land preservation policy is a fundamental goal of land policy. Northeast China has experienced significant cultivated land expan-sion due to rigorous compensation policies over the past two decades, re-sulting in sustainable increases in grain output. This research employs re-mote sensing data to examine the spatial-temporal pattern and vulnerability of newly increased cultivated land expansion in Northeast China and its potential impact on food security. Results indicate a 3.08% increase in newly increased cultivated land from 2000 to 2020, with the majority located in the Sanjiang Plain's humid area and Inner Mongolia's arid and semiarid regions. with 58.54% of it being at grade 6-10, and the reduced cultivated land all at grade 1. Additionally, 62.84% of the newly increased cultivated land was in ecologically fragile areas, while the rest were in mildly and severely vulnerable areas. Temperature insta-bility was negatively correlated with cultivated land expansion, while grain production was negatively correlated with cultivated land vulnerability. The increase in grain production at the expense of cultivated land ecology is a potential threat to national food security. The vulnerability of cultivated land is negatively and significantly related to grain yield, suggesting an adverse impact on national food security. The poor quality of newly increased cultivated land in Northeast China, characterized by ecological fragility, may lead to short-term gains in grain yield but not guarantee long-term stability. This study found a significant negative correlation between grain yield and cultivated land ecological vulnerability in Northeast China. Thus, protection measures should focus on increasing high-quality and ecologically sound cultivated land to ensure long-term grain production stability. Priority should be given to high-quality and ecologically sound cultivated land for inclusion in high-standard cultivated land construction zones to enhance protection efforts.

How to cite: Wang, J., Liu, Z., Li, Z., and Liao, X.: Identify the spatial-temporal pattern of the increased Cultivated land and its vulnerability in Northeast China from 2000 to 2020 , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22312, https://doi.org/10.5194/egusphere-egu24-22312, 2024.

EGU24-3603 | ECS | Posters on site | EOS4.3

Bridging the gap between climate scenarios and law - a roadmap for mutual contributions 

Haomiao Du, Edward Brans, Murray Scown, Hsing-Hsuan Chen, Vassilis Daioglou, Mark Roelfsema, Annisa Triyanti, Dries Hegger, Leila Niamir, Marleen van Rijswick, Liping Dai, Peter Driessen, Yann du Pont, Dennis van Berkel, and Detlef van Vuuren

To bridge the knowledge gap between climate scenarios and law, this presentation is aimed to demonstrate currently demanded mutual contributions by legal professionals and integrated assessment modellers on 1) how legal knowledge can be integrated into climate scenarios and 2) how scientific evidence generated from climate scenarios can better guide climate litigation cases. We expect that this could support judges in making trade-offs in climate-related court cases and could contribute to the acceptance of decisions by judges in such cases. Given the emissions gap and the measures that must be taken to comply with the Paris Agreement, the latter is likely becoming more relevant.

Regarding the first part, the results are based on an empirical research project on Improving the Integration of Legal Knowledge and Scholars in Climate Scenario Assessments (https://www.uu.nl/en/research/sustainability/improving-the-integration-of-legal-knowledge-and-scholars-in-climate-scenario-assessments) and a workshop  (https://www.uu.nl/en/research/sustainability/workshop-report-promoting-the-mutual-understanding-between-legal-and-governance-scholars-and-climate) resulted from this project held in May 2023. Via interviews and focus-group discussions with 24 experts in climate modelling, climate law and politics, and ethics, our research highlights four legal aspects for integration, which are: 1) implementation end enforcement of climate targets, 2) key normative principles, 3) legal uncertainties, and 4) the applicability of scenarios in regional and local legal contexts. Considering the challenges of integration due to epistemic distinctions between disciplines, experts held different opinions on the feasibility of integrating those four aspects. Regarding actionable steps for the short term, revising narratives and a ‘legal reality check’ are the most agreed ones. The former refers to adding legal obligations that safeguard justice, fairness and fundamental human rights - traceable to various treaties - to narratives of the global futures. The latter refers to scrutinising the ‘shared feasibility space’ between law on the one hand and modelled scenarios and emission reduction pathways on the other: it can be the compatibility of legal principles with modelled scenarios based on different assessment criteria (e.g. fair share of burdens), or to compare scenarios with and without regulatory boundary conditions in a specific jurisdiction on a specific mitigation solution (e.g. BECCS scenarios).

Regarding the second part, the currently ongoing research focuses on the adoption of authoritative scientific evidence from climate scenarios - typically the projections referred to in the IPCC reports - in climate litigation cases. First, inspired by the Daubert Criteria, this research explores the possibility of developing guidelines for judges to deal with scientific uncertainties contained in multiple projected futures and determining admissibility of scientific evidence. Second, seeing the increasing reference to ‘open norms’ (e.g. due diligence, fair share) and fundamental human rights (to private life or a healthy environment) in court cases, modelled scenarios could provide information for guiding judges in their interpretation of key concepts such as carbon budgets, fair share, emission gap, appropriate emission reduction obligations, and climate-induced harm and loss and damage. We expect that this could be beneficial to the supportability of judges' decisions in climate cases.

How to cite: Du, H., Brans, E., Scown, M., Chen, H.-H., Daioglou, V., Roelfsema, M., Triyanti, A., Hegger, D., Niamir, L., van Rijswick, M., Dai, L., Driessen, P., du Pont, Y., van Berkel, D., and van Vuuren, D.: Bridging the gap between climate scenarios and law - a roadmap for mutual contributions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3603, https://doi.org/10.5194/egusphere-egu24-3603, 2024.

EGU24-5662 | ECS | Posters on site | EOS4.3

Litigation challenging over-reliance on carbon dioxide removal requires quantitative feasibility assessment 

Oliver Perkins, Peter Alexander, Almut Arneth, Calum Brown, James Millington, and Mark Rounsevell

Carbon dioxide removal (CDR) is an emerging frontier in climate change litigation1. CDR must play an important role in achieving global climate targets, by compensating for hard-to-abate emissions (such as from international transport). Yet, over-reliance on CDR in government and corporate decarbonisation plans may serve as a strategy to commit to climate action on paper, whilst making inadequate present-day emissions’ reductions. Therefore, litigation may be necessary to highlight where CDR commitments contribute to a credible decarbonisation plan, and where they are primarily employed as a delaying tactic. Hence, litigation arguing that a given level of CDR deployment represents an unacceptable risk to the achievement of legal climate targets must have clarity around plausible levels of real-world delivery.

Land-based CDR methods, such as afforestation and bioenergy with carbon capture and storage, frequently appear in both modelled decarbonisation scenarios and government policies. Here, we argue that quantitative assessment of the feasible potential of land-based CDR is vital to the success of CDR-focused litigation. Firstly, we highlight key land system processes that will constrain real-world CDR delivery to levels well-below the techno-economic assessments presented in the IPCC 6th Assessment Report (AR6). These constraining processes include land tenure and food insecurity, monitoring and verification, and impermanence due to biophysical disturbances and policy change. Quantifying the likely impact of such factors can fast-track successful CDR litigation by demonstrating the scale of the gap between CDR pledges and plausible real-world potentials.

Further, after Perkins et al., 2, we outline research frameworks that can deliver a quantified feasible potential for land-based CDR within the IPCC AR7 process, and highlight emerging trans-disciplinary methods making progress towards this goal. These methods include geospatial coupled socio-ecological model ensembles, which can capture interactions and feedbacks between socio-economic and biophysical drivers in the land system at global scale. Typically, such ensembles include coupling of spatial agent-based models of land user behaviour with dynamic global vegetation models and non-equilibrium agricultural trade models - which can represent system shocks such as geopolitical instability and extreme weather events. We conclude by arguing that quantitative feasibility assessment must be made a high priority in CDR research to prevent widespread over-reliance on CDR in decarbonisation policies.

1. Stuart-Smith, R.F., Rajamani, L., Rogelj, J., and Wetzer, T. (2023). Legal limits to the use of CO2 removal. Science 382, 772–774. 10.1126/science.adi9332.

2. Perkins, O., Alexander, P., Arneth, A., Brown, C., Millington, J.D.A., and Rounsevell, M. (2023). Toward quantification of the feasible potential of land-based carbon dioxide removal. One Earth 6, 1638–1651. 10.1016/j.oneear.2023.11.011.

How to cite: Perkins, O., Alexander, P., Arneth, A., Brown, C., Millington, J., and Rounsevell, M.: Litigation challenging over-reliance on carbon dioxide removal requires quantitative feasibility assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5662, https://doi.org/10.5194/egusphere-egu24-5662, 2024.

EGU24-8458 | ECS | Posters on site | EOS4.3

Save the Climate but Don’t Blame Us: Corporate Responses to Climate Litigation 

Noah Walker-Crawford

Fossil fuel companies are no longer denying anthropogenic climate change in recent climate litigation but question the validity of climate science for establishing legal responsibility. Past research on social movement legal mobilization has primarily focused on plaintiffs’ perspectives, showing how they use the judicial process as a site of knowledge production. Drawing attention to the other side, I conduct an analysis of scientific disputes in major climate change lawsuits and develop a typology for studying defendants’ evidentiary arguments. Defendants build evidentiary counter-narratives, challenge the substantive quality of plaintiffs’ claims, and attack the scientific integrity of compromising evidence. Litigants’ legal narratives and factual claims are linked to broader normative concerns about how the underlying issues should be resolved. Fossil fuel companies’ legal arguments reflect broader strategies to evade responsibility for climate change.

How to cite: Walker-Crawford, N.: Save the Climate but Don’t Blame Us: Corporate Responses to Climate Litigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8458, https://doi.org/10.5194/egusphere-egu24-8458, 2024.

EGU24-12601 | ECS | Posters on site | EOS4.3

Towards Evaluating the Financial Responsibility of Carbon Majors for Climate-Related Damages 

Marina Andrijevic, Carl-Friedrich Schleussner, Jarmo Kikstra, Richard Heede, Joeri Rogelj, Sylvia Schmidt, and Holly Simpkin

In light of the global energy crisis and escalating climate change impacts, the liability of major fossil fuel companies is receiving heightened scrutiny, particularly in the context of climate litigation. This study initially establishes the feasibility of attributing climate damages to these companies. Utilizing the social cost of carbon methodology, we evaluate the damages inflicted by the top 25 oil and gas emitters from 1985 to 2018, comparing these to their financial profits. Our central estimate suggests partial damages of approximately 20 trillion USD, with the companies’ financial gains surpassing this by 50%, totaling around 30 trillion USD. This indicates the potential of carbon majors to cover their attributed damages while maintaining significant profits. In our analysis, we also explore how varying approaches to assigning responsibility and handling uncertainties in climate damages can markedly influence these findings. Additionally, we explore the role of sovereign wealth funds in perpetuating fossil-fuel derived wealth and the ensuing liability questions.

How to cite: Andrijevic, M., Schleussner, C.-F., Kikstra, J., Heede, R., Rogelj, J., Schmidt, S., and Simpkin, H.: Towards Evaluating the Financial Responsibility of Carbon Majors for Climate-Related Damages, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12601, https://doi.org/10.5194/egusphere-egu24-12601, 2024.

EGU24-15814 | ECS | Posters on site | EOS4.3

Quantifying the human-induced climate change impact on heat-related mortality events in Europe with Extreme Event Attribution Methods  

Thessa M Beck, Lukas Gudmundsson, Dominik L Schumacher, Sonia I Seneviratne, Hicham Achebak, and Joan Ballester

Numerous Extreme Event Attribution (EEA) studies have consistently shown that human-induced climate change has increased the likelihood of extreme heat events. The increasing relevance of these studies in the context of climate litigation underscores the demand for the quantification of climate change impacts. Heat, as the primary contributor to weather-related mortality on the European continent, has caused more than 61,000 heat-related deaths in Europe during the 2022 summer. We carry out this proof-of-concept study in which we apply Extreme Event Attribution methods combined with epidemiological models to quantify how anthropogenic warming has influenced extreme heat-related mortality events in Europe. In contrast to most health impact studies, we utilize open-access mortality data from Eurostat, which is available in near-real time.

Because of the complex, non-linear relationship between temperature and mortality, we conduct separate Extreme Event Attribution analyses for (i) temperature extremes and (ii) associated heat-related mortality events in 232 distinct administrative regions spanning over 35 European countries. Our findings reveal that the probability of the maximum weekly values observed in 2022 has increased 12-fold [95th CI 3.51-147.15] for temperature and tripled [95th CI 1.02-18.63] for mortality compared to the pre-industrial baseline. Notably, we identify significant geographical disparities, e.g. in Spain the mortality risk is even 30 times higher [95th CI 3.33 – 1218.14] due to anthropogenic warming.

We find a statistically significant trend in 70% [90%] of the regions at the 0.95 [0.90] significance level, and across all age and sex groups, except for women aged 65 years or less, indicating that anthropogenic warming affects almost the entire European population.

This study establishes a foundation for subsequent analyses, not only for heat-related mortality events observed on different temporal and spatial scales but also for enabling an examination of other weather events and associated health impacts. By combining climate sciences and techniques with epidemiology and health data, it is possible to calculate the contribution of climate change to changes in health risks and mortality burdens by sociodemographic categories, such as sex, age, socioeconomic level, or comorbidities, especially in vulnerable groups. This transdisciplinary work has to potential to provide key information for climate-related health lawsuits and opens the door to inter- and transdisciplinary perspectives on how to integrate geoscience and epidemiology insights in litigation.

How to cite: Beck, T. M., Gudmundsson, L., Schumacher, D. L., Seneviratne, S. I., Achebak, H., and Ballester, J.: Quantifying the human-induced climate change impact on heat-related mortality events in Europe with Extreme Event Attribution Methods , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15814, https://doi.org/10.5194/egusphere-egu24-15814, 2024.

EGU24-16721 | ECS | Posters on site | EOS4.3

Does climate change violate children’s rights? Investigating the use of scientific evidence in child and youth-led climate litigation 

Rosa Pietroiusti, Sam Adelman, Annalisa Savaresi, and Wim Thiery

Climate change is already increasing the frequency, intensity and duration of many extreme weather events around the world, as well as driving impacts on communities through slow-onset changes, and will continue to do so with each additional degree of warming. Young and future generations will face an ever-greater number of such events during their lifetimes, raising concerns regarding the intergenerational inequity inherent in climate change. In response to these concerns, child and youth-led climate litigation is emerging as an avenue to push for more ambitious climate policies at national and regional scales, by applying legal duties and obligations in a forward-looking way and presenting courts with  scientific evidence of observed and projected climate risks and impacts. Recent complaints led by young people, including, for example, Sacchi et al. v. Argentina et al., lodged in 2019 with the United Nations Committee on the Rights of the Child and Duarte Agostinho et al. v. Portugal et al., which was heard in 2023 by the European Court of Human Rights, have broken new ground by bringing the rights of children and future generations to the fore. Based on a review of recent and ongoing cases, we will investigate (i) what harms are claimed by youth plaintiffs, and (ii) whether, how and to what extent scientific evidence is used to support their claims. By comparing the cases in relation to their claims, jurisdictional frameworks, reference to human and/or children’s rights, and status, we will shed light on how youth applicants have addressed the main challenges of this specific category of climate litigation, including meeting the victimhood requirement, and what role evidence from the geosciences and other scientific fields has played.

How to cite: Pietroiusti, R., Adelman, S., Savaresi, A., and Thiery, W.: Does climate change violate children’s rights? Investigating the use of scientific evidence in child and youth-led climate litigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16721, https://doi.org/10.5194/egusphere-egu24-16721, 2024.

EGU24-17250 | ECS | Posters on site | EOS4.3

From Glaciers to Courtrooms: Translating Natural Science Concepts into Legal Frameworks for Climate Litigation 

Randy Muñoz, Christian Huggel, Wilfried Haeberli, Martin Mergili, Adam Emmer, Lukas Arenson, and Matthieu Sturzenegger

The integration of natural science concepts into climate change litigation, particularly in cases related to glacier lake outburst floods (GLOFs) in mountainous regions like the Andes, faces significant challenges due to the differing nature of scientific and legal frameworks.

Scientific understanding of climate change impacts on phenomena such as GLOFs relies heavily on scenarios, modeling, and projections that evolve over time with advancements in technology and knowledge. These models need to be comprehensive, and consider an array of factors including glacier retreat, temperature changes and various risk factors. However, legal standards often require definitive proof of causation. There may arise a discrepancy creating  a gap in case of prevailing uncertainties inherent to high-mountain processes which may not always meet the exacting evidentiary requirements of litigation.

An illustrative example of this challenge is the case of a citizen in Huaraz, in the Andes of Peru, using a major German energy producer over the risks of a catastrophic flood from a GLOF at Lake Palcacocha. The German court’s decision to admit this case is groundbreaking in climate litigation. It implies a recognition of legal responsibilities of large emitters for potential losses and damages caused by anthropogenic climate change globally, provided a causal relation between emissions and risk can be established. This case exemplifies the challenge in linking complex scientific causation with legal accountability.

In the Palcacocha case, the German court defined to distinguish between i) the hazard and risk posed to the plaintiff in Huaraz, and ii) the attribution to anthropogenic climate change and the emissions produced by the defendant. Here we report on the geoscientific studies undertaken to analyze the hazard situation posed by potential rock and ice avalanches, impacting the glacial lake and producing potentially devastating floods in the city of Huaraz. Critical among other are concepts and methods to quantify probability of occurrence of an event, and the effect of cascading slope and mass flow processes.

In conclusion, the challenges in adapting natural science concepts for climate change litigation, particularly regarding GLOFs, stem from different concepts, standards of proof, and conceptual understandings in science and law. Bridging this gap is essential for effective climate litigation and requires innovative interdisciplinary approaches that facilitate the translation of scientific findings into legally cogent arguments. The framework, methods and standards we applied in the case of Palcacocha could serve for other litigation cases in similar environments, highly impacted and vulnerable to anthropogenic climate change. 

How to cite: Muñoz, R., Huggel, C., Haeberli, W., Mergili, M., Emmer, A., Arenson, L., and Sturzenegger, M.: From Glaciers to Courtrooms: Translating Natural Science Concepts into Legal Frameworks for Climate Litigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17250, https://doi.org/10.5194/egusphere-egu24-17250, 2024.

EGU24-18367 | ECS | Posters on site | EOS4.3

Contributions of carbon majors to historical heatwaves 

Yann Quilcaille, Lukas Gudmundsson, Thomas Gasser, and Sonia I. Seneviratne

While human-induced climate change shows no sign of slowing down, calls to steer to a more sustainable path grow louder. Countries are sued for their lack of ambitious climate action, and high-emitting companies for their responsibilities. However, climate litigation is often impeded by the lack of scientific evidence directly relevant to the legal cases. Available attribution research can provide support for claims, but some key elements are still missing. First, event attribution studies are limited to a few selected events, depending on available researchers’ time and interests. Second, the contributions of high-emitting companies to recent extreme events has not yet been quantified. Here, we fill in both of these gaps. We present the first collective attribution of 149 historical heatwaves reported over the 2000-2021 period. We apply a well-established extreme weather attribution (Philip et al., 2020) to heatwaves reported in the EM-DAT database (EM-DAT, 2023). For each listed heatwave, we identify the event in observational data (ERA5, BEST) and CMIP6 data, then we estimate its occurrence probabilities for present and pre-industrial climate conditions. Subsequently, we calculate the contributions in global mean surface temperature of 110 fossil fuels and cement companies using their CO2 and CH4 emissions (Heede, 2014) and the reduced-complexity Earth system model OSCAR (Gasser et al., 2017). These contributions combined to the collective attribution allow for the calculation of the contributions of these carbon majors to all of the analyzed historical heatwaves. These carbon majors represent 76% of the CO2 emissions over 1850-2021, and half of this 76% is due to only six actors (nation-state of China for coal & cement; nation-state of the Former Soviet Union for coal, oil and gas; Saudi Aramco; Chevron; ExxonMobil; Gazprom). In terms of global mean surface temperature, these six majors contribute to 0.30°C, while the others contribute to an additional 0.34°C. The majority of heatwaves are made substantially more probable and intense due to these six carbon majors. Though, other carbon majors cannot be neglected, as their sole contribution may be enough to make some heatwaves possible. This attribution of a large number of heatwaves and the link to the contributions of the carbon majors will provide useful resources for climate litigation, paving the way towards their legal responsibility.

 

EM-DAT, CRED / UCLouvain: www.emdat.be, last access: 09.01.2024.

Gasser, T., Ciais, P., Boucher, O., Quilcaille, Y., Tortora, M., Bopp, L., and Hauglustaine, D.: The compact Earth system model OSCAR v2.2: Description and first results, Geoscientific Model Development, 10, 271-319, 10.5194/gmd-10-271-2017, 2017.

Heede, R.: Tracing anthropogenic carbon dioxide and methane emissions to fossil fuel and cement producers, 1854–2010, Climatic Change, 122, 229-241, 10.1007/s10584-013-0986-y, 2014.

Philip, S., Kew, S., van Oldenborgh, G. J., Otto, F., Vautard, R., van der Wiel, K., King, A., Lott, F., Arrighi, J., Singh, R., and van Aalst, M.: A protocol for probabilistic extreme event attribution analyses, Adv. Stat. Clim. Meteorol. Oceanogr., 6, 177-203, 10.5194/ascmo-6-177-2020, 2020.

How to cite: Quilcaille, Y., Gudmundsson, L., Gasser, T., and Seneviratne, S. I.: Contributions of carbon majors to historical heatwaves, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18367, https://doi.org/10.5194/egusphere-egu24-18367, 2024.

EGU24-19683 | Posters on site | EOS4.3

Four roles for geoscientists in climate litigation 

Wim Thiery, Rosa Pietroiusti, Annalisa Savaresi, and Stefaan Smis

The number of climate change lawsuits is exploding,  and so is the need for scientific evidence on climate change in courtrooms. Here we identify four roles that climate researchers can take up in light of these recent developments: expert witness, party support, amicus curiae, and litigation-relevant research. For each role, we highlight recent examples and best practices, as well as pitfalls and their overcoming. These examples overall highlight the urgent need for interdisciplinary research between climate science and legal scholars to bring both research communities closer together. In addition, and in activities where exchange with litigators takes place, it is critical that ingestion of scientific information occurs right from the start of the litigation process.

How to cite: Thiery, W., Pietroiusti, R., Savaresi, A., and Smis, S.: Four roles for geoscientists in climate litigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19683, https://doi.org/10.5194/egusphere-egu24-19683, 2024.

EGU24-20599 | Posters on site | EOS4.3

How stocks judge COPs: market impacts of climate conferences 

Robin Lamboll and Alaa Al Khourdajie

This study investigates the impact of Conference of the Parties (COP) meetings on the stock prices of oil companies and the broader implications for renewable energy sectors to examine the relationship between international climate negotiations and market responses in the energy sector. The analysis focuses on stock price movements and volatility within the oil and renewable energy industries. We look at the data of the 10 largest stocks in each category and investigate their behaviour during COP. The findings indicate that, with the exception of notable negative stock price movements during COPs 20 and 21 (before and during the signing of the Paris Agreement), COP meetings generally do not significantly influence the value of oil companies. There is also no impact on oil prices during COP itself, though some sign of disturbance in the period immediately afterwards. The study also addresses the renewable energy sector, finding no strong effects from most COP meetings but a notable decrease in stocks during COP6's failure. We conclude that the majority of COPs have not produced market signals indicating a green transition, although these signals are potentially detectable.

How to cite: Lamboll, R. and Al Khourdajie, A.: How stocks judge COPs: market impacts of climate conferences, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20599, https://doi.org/10.5194/egusphere-egu24-20599, 2024.

The Climate Litigation Network supports national organisations that are taking litigation action against their governments in respect of the adequacy and implementation of national climate policies and targets. This presentation will provide an overview of the role in science in climate cases that challenge governments’ overall emissions reductions (“framework cases”) – of which there are more than 100 globally. Drawing from a litigator’s perspective, it will address common legal questions (i.e., harm, causation, foreseeability and remedies) that arise in such cases, and provide examples of how science has been used in case studies. 

Across framework cases, scientific evidence has been critical to success. For example, many cases, including those based on human rights or tort law, require claimants to show how they have been impacted or have suffered harm. In this regard, supporting studies range widely, depending on the facts of the case. These could include studies concerning extreme weather events, flooding, landslides, impacts on crop production and availability to water, and impacts on health or culture. To establish legal liability, claimants typically must show that the government’s actions can be causally linked to the harm, and that the harm was foreseeable. In this regard, attribution science and climate science generally can play a role in evidencing why government action (or lack of action) is contributing to climate change impacts. In terms of remedies, several cases have sought to push governments to adopt emissions reduction targets that reflect their “fair share” of the remaining global carbon budget. Numerous fair share methodologies have been developed by academics, many of which seek to reflect obligations and principles set out in the United Nations Framework Convention on Climate Change and international environmental law. In some cases, there may also be questions concerning loss and damage, which could require detailed analyses of how much damage has been incurred, or could be incurred in future, due to the impacts of climate change.

Drawing on case studies from specific cases, this presentation will highlight the current deployment of science in climate cases against governments and explore new frontiers.

How to cite: Williamson, A.: Challenging governments’ response to the climate crisis: the role of science in climate litigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21949, https://doi.org/10.5194/egusphere-egu24-21949, 2024.

EGU24-758 | ECS | Orals | EOS4.4

Méditerranée 2000: Nurturing climate & ocean awareness 

Pimnutcha Promduangsri, Pariphat Promduangsri, and Estelle Bellanger

Humans have been suffering increasingly from the escalating impacts of climate and ocean change.  Well known examples are droughts, flooding, wildfires, acidification, heatwaves, sea-level rise, extreme storms and biodiversity loss.  If global average temperature rises by more than 1.5°C above pre-industrial levels, multiple climate tipping points will be triggered, and indeed, some already are.  This is and will be devastating for people around the world, especially those in coastal areas.  Thus, the need for immediate and informed action has become urgent.

This presentation will outline some of the many concrete, local actions in the area of climate and ocean, undertaken by Méditerranée 2000 (Med2000), an environmental association in the South of France.  Since 1989, the association has committed its efforts and educational programs to promoting sustainable development.  Each year, the association educates more than 25,000 young people and adults, led by a team of ten specialized speakers.  Med2000’s initiatives include awareness campaigns about climate and ocean change, hands-on educational activities in local schools and events for the general public.

How to cite: Promduangsri, P., Promduangsri, P., and Bellanger, E.: Méditerranée 2000: Nurturing climate & ocean awareness, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-758, https://doi.org/10.5194/egusphere-egu24-758, 2024.

Academic researchers have long been advocates of various causes in the public arena; their public advocacy to take normative positions regarding various moral, political or social issues is not new. Today, however, in the face of the many challenges facing our society, the question of researchers' public positions, particularly in relation to the environment and climate change, is being raised anew. A number of climate scientists are committed in a variety of ways, from signing op-eds to participating in the work of NGOs or think tanks, supporting legal actions or writing blog posts. In addition, the development of traditional and social media has significantly increased the public exposure of these researchers. At the same time, serious questions are being raised within the research community. Many of its members are debating the ways in which researchers can engage in such public advocacy, its advisability, and even its very principle. However, these debates are currently taking place in informal settings and, given the extensive individual experience of a number of colleagues, it is probably time to engage in this discussion in a more collective and organised way, as is done in other research communities.

Here are some examples of questions that might be discussed. How can researchers engage in public advocacy safely and responsibly? What is the role of the scientist versus the expert versus the citizen versus the activist? Can a researcher be neutral when taking a public stance? What is the risk of appearing naive, manipulated or irrelevant? How should researchers deal with vested interests and private actors? Should the climate community research geoengineering? For whom should researchers develop climate services?

Because addressing these issues involves a tension between personal values that may go beyond those shared by the scientific community, they are essentially novel ethical questions. Some may be so intimidating that many researchers choose not to engage publicly. Care must therefore be taken to organise the exchange properly, for example by creating safe internal spaces for debate or by inviting experts from other disciplines.

The French CNRS Ethics Committee has recently published on opinions on these issues[1], which I will use as a starting point for a broader discussion.


[1]  https://comite-ethique.cnrs.fr/en/comets-opinion-freedom-and-responsibility-academic-researchers-public-advocacy/

How to cite: Guilyardi, E.: Freedom and Responsibility: the Ethics of Academic Researchers’ Public Advocacy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1344, https://doi.org/10.5194/egusphere-egu24-1344, 2024.

EGU24-2053 | Orals | EOS4.4

Perceiving Cape-Town-Geoethics (CTG) through Symbolic Universes (SU) 

Martin Bohle, Rika Preiser, and Eduardo Marone

Cultural milieus determine the worldviews and practices of individuals and groups, including the reception of norms that guide them. Semiotic Cultural Psychological Theory (SCPT) methods, such as Symbolic Universes (SU), describe relationships of reception, worldviews and practice, which also applies to geo-philosophical matters [1]. This essay outlines how geoethics, for example, the Cape Town Geoethics (CTG), might be received in different cultural milieus.

The Cape Town Statement on Geoethics was proposed in 2016 at the 36th IGC [2] and is the most accessible resource on geoethics. It bundles various concepts in a Kantian/Aristotelian virtue ethics framework, illustrated, for example, by the Geoethical Promise [3].

The SU method describes the understanding, insights, and behaviour of groups of people expressing their respective cultural milieus. Extensive fieldwork identified five SU for people of European (Western) cultures [4]. The SUs called "Ordered Universe", "Interpersonal Bond", "Caring Society", "Niche of Belongingness", and "Others' World" categorise milieus, for example, in terms of relation to power and institutions or sources of trust. They corroborated with the Kohlberg hierarchy of the level of societal coordination [5] that is applicable to associate CTG and the worldviews of individuals and groups [6].

Comparing CTG and SU indicates: (1) CTG resonates most positively with people of the cultural milieu “Ordered Universe” (highest Kollberg level); (2) in other milieus, the reception of the CTG will be “measured”; (3) reception will be adverse for the milieu “Others' World” (lowest Kohlberg level). Hence, considering the quantitative distribution of SUs (in Europe), European citizens' reception of CTG is likely restrained.

Given complex-adaptive social-ecological systems of the World and Nature couple world views, human practices, and societal and natural systems [7] (see example: [8]), whether variants of CTG “fitted to different milieus” should be developed is of practical relevance. The perception of norms and their acceptance or rejection is a system feature, of which geoethics should not be agnostic.

[1] Bohle M (2019) “Homo Semioticus” Migrating Out of Area? In: Salvatore S, et al. (eds) Symbolic Universes in Time of (Post)Crisis. Springer Berlin Heidelberg, Cham, pp 295–307

[2] Di Capua G, et al. (2017) The Cape Town Statement on Geoethics. Ann Geophys 60:1–6. https://doi.org/10.4401/ag-7553

[3] Matteucci R, et al. (2014) The “Geoethical Promise”: A Proposal. Episodes 37:190–191. https://doi.org/10.18814/epiiugs/2014/v37i3/004

[4] Salvatore S, et al (2019) The Cultural Milieu and the Symbolic Universes of European Societies. In: Salvatore S, et al. (eds) Symbolic Universes in Time of (Post)crisis. Springer, Cham, pp 53–133

[5] Kohlberg L (1981) The Philosophy of Moral Development: Moral Stages and the Idea of Justice. Harber & Row, San Francisco

[6] Bohle M, Marone E (2022) Phronesis at the Human-Earth Nexus: Managed Retreat. Front Polit Sci 4:1–13. https://doi.org/10.3389/fpos.2022.819930

[7] Preiser R, Woermann M (2019) Complexity, philosophy and ethics. In: Galaz V (ed) Global Challenges, Governance, and Complexity. Edward Elgar Publishing., Cheltenham, pp 38–62

[8] Talukder B, et al. (2023) Complex Adaptive Systems-Based Conceptual Framework for Modeling the Health Impacts of Climate Change. J Clim Chang Heal 100292. https://doi.org/10.1016/j.joclim.2023.100292

How to cite: Bohle, M., Preiser, R., and Marone, E.: Perceiving Cape-Town-Geoethics (CTG) through Symbolic Universes (SU), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2053, https://doi.org/10.5194/egusphere-egu24-2053, 2024.

EGU24-2607 | Posters on site | EOS4.4

Geoethics literacy:  Clarifying values, principles and behaviour 

David Crookall, Pimnutcha Promduangsri, and Pariphat Promduangsri

Learning about geoethics is not easy partly because the area is relatively new (having emerged in the early 2010s), the concepts are sometimes difficult to fathom and geoethics touches on such a wide area of geoscience phenomena and on such a variety of human issues.

Learning through active, participatory engagement has been developing since the 1960s, and is now deployed, albeit sporadically, across the full educational and training spectrum (from the humanities, through the social sciences to the hard sciences).  Methods that have developed in this learning paradigm include project work, internships, experiential learning, simulation/gaming, values clarification and many more.  We contend that participatory methods are an effective way in which to learn, as supported by much research.

Our poster invites you to participate in a game-like, values clarification exercise.  We have developed a new version of an exercise that we have used in several places (Austria, Costa Rica, France, online) to unravel the knotty relations among values, principles and behaviours related to geoethical issues and dilemmas.

It is possible to play alone, but it is more enlightening and engaging to play in pairs or small groups.  Please bring a friend or two to our poster and participate in our exercise.  The basic process of the exercise can be adapted to your own specific areas of interest.  We look forward to seeing you – please bring a pencil.

(This poster was originally intended as a workshop in a short course, but our SC proposal was declined.)

How to cite: Crookall, D., Promduangsri, P., and Promduangsri, P.: Geoethics literacy:  Clarifying values, principles and behaviour, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2607, https://doi.org/10.5194/egusphere-egu24-2607, 2024.

EGU24-3568 | Posters on site | EOS4.4

Exploring the horizon of geosciences through the lens of geoethics 

Silvia Peppoloni and Giuseppe Di Capua

Geosciences play an indispensable role in the functioning of contemporary societies. Nevertheless, the technological aspects associated with the practical application of geoscientific knowledge, should not overshadow the fundamental contribution of geosciences to shaping human thought. Geosciences have not only influenced but continue to shape our perception of the world, its interrelationships, and evolution.

The ongoing ecological crisis, with its environmental, social, cultural, economic, and geopolitical implications, has stemmed from an imprudent trajectory in human development. Regrettably, there have been instances where geosciences have contributed to this irresponsible path. This oversight has led to an undervaluation of the social and cultural significance inherent in geological disciplines and the crucial role they can play in addressing current global challenges to support human societies.

Geoethics, as the ethics of responsibility towards the Earth system, is grounded in the comprehensive understanding provided by geoscientific knowledge of the complexity of reality. It stands out as the optimal tool for cultivating a new perspective on geosciences, recognizing them as fundamental disciplines crucial for addressing global environmental challenges. This recognition extends beyond technical considerations, emphasizing their cultural significance. By virtue of their epistemological foundations, the geosciences collectively represent an invaluable reservoir of knowledge for human civilization. They are indispensable for redefining the intricate relationship that binds us, as humans, to the Earth.

For this reason, geoethical thought should serve as a complementary element to knowledge in the education of geoscientists. It aims to furnish them with a principled framework and ethical values, offering guidance for any application of geoscientific knowledge to the natural environment and human communities. Additionally, geoethical thought is the ground on which to set a shared, global ethical foundation, facilitating the advancement of our interactions with nature. It seeks to actualize an ecological humanism that forms the basis for human well-being and a more sustainable development of socio-ecological systems. The geoethical perspective redefines the cultural significance and objectives of the geosciences. Geoeducation and communication emerge as fundamental tools for bridging the gap between geosciences and society. They play a crucial role in promoting geoscientific knowledge, highlighting not only its scientific value in providing technical solutions to the ecological crisis but also emphasizing the philosophical dimension of geosciences, the geosophy of living consciously and responsibly within the Earth system.

How to cite: Peppoloni, S. and Di Capua, G.: Exploring the horizon of geosciences through the lens of geoethics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3568, https://doi.org/10.5194/egusphere-egu24-3568, 2024.

EGU24-3586 | Posters on site | EOS4.4

An infrastructure for researching on geoethics and facilitating its international promotion 

Giuseppe Di Capua and Silvia Peppoloni

The development of the theoretical foundations of geoethics and its practical applications have had a notable boost in recent years, seeing the involvement of a growing number of scholars from different disciplines. This has increasingly necessitated the creation of spaces where reflections, discussions, results, and study materials can be shared. The network of scholar relationships has progressively developed physical and conceptual spaces for discussions. The goal has been to sustain conceptual consistency in geoethical thinking by anchoring reflections in the discipline's historical evolution and fostering further developments through open analysis, welcoming contributions from diverse disciplinary backgrounds. Today, what can be defined as a research infrastructure on geoethics and the promotion of its contents possesses a complex structure, serving as a convergence point for various cultural and scientific experiences.

At the core of this infrastructure lies the International Association for Promoting Geoethics - IAPG (https://www.geoethics.org), established in 2012. It consists of an Executive Committee, national sections, and Task Groups focusing on specific topics within geoethics. More recently, two new entities have augmented this infrastructure: i) the Commission on Geoethics of the International Union of Geological Sciences (IUGS), established in February 2023, that is the supporting branch of the IAPG to the IUGS and the IUGS body that officially deals with geoethics and social geosciences for the Union; ii) the Chair on Geoethics of the International Council for Philosophy and Human Sciences (CIPSH, an organization operating under the umbrella of UNESCO), established in December 2023, with the aim of expanding and reinforcing an international research network of institutions, not-governmental organizations, and individual scholars to foster interdisciplinary initiatives for bridging geosciences, humanities, and social sciences through geoethics.

The research infrastructure on geoethics has been enriched over time with two editorial initiatives: a) SpringerBriefs in Geoethics series by Springer Nature (https://www.springer.com/series/16482), founded in 2020 and supported by the IAPG, that envisions a series of short publications that aim to discuss ethical, social, and cultural implications of geosciences knowledge, education, research, practice and communication; b) the Journal of Geoethics and Social Geosciences (https://www.journalofgeoethics.eu/), a diamond open access publication of the National Institute of Geophysics and Volcanology (Rome, Italy) and supported by the IAPG, founded in 2021.

Finally, the research infrastructure on geoethics is complemented by the School on Geoethics and Natural Issues (the “Schola”), founded in 2019 (https://www.geoethics.org/geoethics-school). The “Schola” is a place for teaching and learning of the principles and values of geoethics in the light of the philosophy and history of Earth sciences. The intent is to provide background knowledge and the evaluation skills necessary to understand the complex relationship between human action on ecosystems and the decisions geoscientists make in the discipline that impact society, including improving the awareness of professionals, students, decision-makers, media operators, and the public on an accountable and ecologically sustainable development.

How to cite: Di Capua, G. and Peppoloni, S.: An infrastructure for researching on geoethics and facilitating its international promotion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3586, https://doi.org/10.5194/egusphere-egu24-3586, 2024.

The ocean has started to attract more attention in the recent past with the notions of Blue Economy and Blue Growth becoming rallying points for a new frontier for investments [1]. Many countries and institutions prepare policy papers promising to end poverty, a push for new technologies and profits to fund the development. A recent systematic review of the literature [2], however, found no trace of articulated ethics and justice notions in midst of all the lofty hope and hype surrounding the often blurred concepts. The increasing financialisation of technological developments accelerated through digitalisation and the internet are creating increasing injustices to humans and harm to nature. But, as Rushkoff argues [3], the possibilities for feedback and more circular reasoning have potential to teach everybody that there is no escape from the natural world, thus weaning us from the hyperbole of permanent exponential growth. Here it is argued that critically engaged ocean and geo-sciences with their inherent message of a changing planet through deep time can contribute to debunking the ahistorical promise of fixing self-created problems by starting on a presumed ‘clean slate’. We frequently observe a pattern of wanting to solve the damage provoked by one technology with more technology, e.g. deep sea mining [4] or further technology development in fisheries and aquaculture [5]. At country level, these deliberately disruptive industrial approaches often pay little attention to working with the affected small-scale wild food producers who account for a quarter of global production. Instead, harnessing a combination of traditional and indigenous knowledges and providing intelligible access to the sciences holds significant potential for less destructive pathways. That would also be consonant with the promotion of knowledge co-creation during the UN Ocean Decade in pursuit of a vision of ‘the science we need for the ocean we want’. Practice of co-creation will require some rethinking of the self-image of many sciences and adaptations to typical project formulation and flows. In return, this is expected to produce valuable new insights in addition to opportunities for cooperation and blue justice as steps towards transformations based on ethical principles.

 

[1] World Bank. (2016). Oceans 2030: Financing the blue economy for sustainable development. Blue Economy Development Framework, Growing the Blue Economy to Combat Poverty and Accelerate Prosperity. World Bank Group, Washington DC.

[2] Das, J. (2023). Blue Economy, Blue Growth, Social Equity and Small-scale Fisheries: A Global and National Level Review. Studies in Social Science Research, 4(1):45 p. DOI: https://doi.org/10.22158/sssr.v4n1p38

[3] Rushkoff, D. (2022). Survival of the richest. Escape fantasies of the tech billionaires. Scribepublications, UK, ISBN 978-1-915590-24-4, 212 p.

[4] Zenghui Liu, Kai Liu, Xuguang Chen, Zhengkuo Ma, Rui Lv, Changyun Wei, Ke Ma. (2023). Deep-sea rock mechanics and mining technology: State of the art and perspectives. International Journal of Mining Science and Technology, 33(9):1083-1115. https://doi.org/10.1016/j.ijmst.2023.07.007.

[5] FAO. (2022). The State of World Fisheries and Aquaculture 2022: Towards Blue Transformation. Rome, FAO. doi:10.4060/cc0461en

How to cite: Nauen, C. E.: Can geosciences help inserting social justice notions into Blue Economy narratives?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4054, https://doi.org/10.5194/egusphere-egu24-4054, 2024.

Science indicates that human impact on the planet's climate is clear. Over the past 30 years, climate change has shifted from being primarily a scientific concern to emerging as one of the defining environmental challenges within our society. However, science alone cannot guide us on how to address this crisis. This challenge is also about how we envision living together, what we collectively value, and the level of risk we are prepared to assume. It fundamentally pertains to the kind of society we aspire to, making education a pivotal component. Inspired by the Paris Agreement, the time has arrived for Climate Change Education. It derives its momentum from the aspirations and mobilization of the youth, making it the most potent transformative action in response to climate change.

Climate Change Education comes with unique and exciting opportunities. Firstly, it offers a chance to learn about science in general and climate science specifically, drawing from authoritative sources like IPCC reports. Secondly, it provides an avenue to acquire life skills, humanities knowledge, and insights into global citizenship, imparting a holistic perspective to the young generation on a global scale. Lastly, it fosters critical thinking, hopeful hearts, and empathy in an ever-evolving educational landscape. However, Climate Change Education presents numerous challenges as it strives to balance the development of cognitive, emotional, and practical aspects within existing educational systems. Educators need to be prepared for this unique combination of ‘head’, ‘heart’, and ‘hands’.

The mission of the Office for Climate Education (OCE) is precisely to empower educators in preparing young generations with a robust understanding of climate change and the skills needed to act as global citizens in a changing world. The OCE, driven by collaboration between climate science and educational communities, develops sets of pedagogical resources, offers teacher professional development opportunities, and facilitates networks of practice worldwide. As a pivotal participant in the newly established Greening Education Partnership, the OCE serves as a bridge between the global landscape of IPCC-based science and the specific needs of local primary and secondary educational systems in over 20 countries.

How to cite: Guilyardi, E. and Wilgenbus, D.: Exciting times for Climate Change Education – from global opportunities to local challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6101, https://doi.org/10.5194/egusphere-egu24-6101, 2024.

The National Association of State Boards of Geology (ASBOG) plays an essential role in supporting the licensing of applied geoscientists in more than 30 states in the United States [1] through promulgating model law, rules, and regulations for professional licensure, [2] by developing and implementing the Fundamentals of Geology (FG) and Practice of Geology (PG) exams, and [3] by providing related educational materials.  The content of the FG and PG exams is driven substantially by the results of Task Analysis Surveys (TAS) taken by practicing geologists and academic geologists.  Before 2023, the exams included content related to ethics reflected in the earlier TAS analytical summaries;  however, ethics content is not included in the 2023 TAS or, reportedly, in the current FG or PG exams.
     ASBOG has a history of including applied ethics in its products and organizational structure.  There is a "Code of Conduct/Harassment Policy and Performance Guidelines" for the ASBOG organization on its website (ASBOG.org).  The "Professional Geologist Model Licensure Law" states that each applicant must "submit a signed statement that the applicant has read and shall adhere to any code of professional conduct/ethics and rules established by the Board..." and that the application "be signed and sworn to by the applicant before a notary public" (ASBOG 2017, lines 844-847).  Its "Model Rules and Regulations" includes a sample "Code of Ethics" for licensed professional geologists (ASBOG 2019, p. 27-29).  
     Geoscience professional organizations in the US and internationally affirm the fundamental importance of ethics in academic and applied geoscience.  Virtually all professional organizations relevant to applied-geoscience practice in the United States (e.g., AAPG, AGI, AGU, AIPG, AEG, ASBOG, GSA, SIPES...) have some form of ethics code that their members are obligated to know and adhere to.  The International Association for the Promotion of Geoethics (IAPG -- www.geoethics.org) curates a list of codes of ethics/professional practice and provides publications and educational opportunities supporting geoethics.  Another essential resource is the "Teaching Geoethics" website (serc.carleton.edu/geoethics -- Mogk and Bruckner, 2014-23).
     Robert Tepel (1995) described the essential connection between licensure laws and professional ethics.  To the extent that there is a lack of ethics content in the current 2023 TAS, candidate handbook, exam preparation resources, and FG and PG exams, ASBOG sends a message that applied ethics might not be a core competency for licensed geoscientists -- a message for which there is essentially no support among geoscience professional organizations.
          I suggest that ASBOG collaborate with IAPG and other relevant organizations to address the problems or concerns that resulted in the reported elimination/reduction of ethics content in the application, preparation, and implementation of its FG and PG exams.  Licensed professional geoscientists must continue to understand that geoethics is foundational for their work within society.  For references and resources, visit CroninProjects.org/EGU-Geoethics2024/.

How to cite: Cronin, V.: The need to include ethics content in professional licensure exams in the US (and worldwide), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6136, https://doi.org/10.5194/egusphere-egu24-6136, 2024.

EGU24-6573 | ECS | Orals | EOS4.4

Proposal for a Geoethics Code for the Geoscientist Community of Chile 

Hernán Bobadilla, Luisa Pinto Lincoñir, Pablo Ramirez, Thiare González, José Benado, Nilda Lay, Tania Villaseñor, Millarca Valenzuela, Mohammad Ayaz Alam, and Alejandro Pérez

The proposal of the Geoethics Code (hereinafter “Code”) of the Geological Society of Chile arises as a strategic objective of the Geoethics Group within this institution. The Code encapsulates the principles and values that ethically guide and protect the professional decisions of geoscientists in Chile to protect society and the environment. Likewise, it establishes standards of conduct from the personal to the environmental dimension of professional and scientific practice. Consequently, the Code serves as a valuable tool to the geoscientist community in Chile, facilitating reflection and decision-making within an ethical framework.

Grounded in the principles and values defined by the Geoethics Group of the Geological Society of Chile and the Cape Town Geoethics Declaration of the International Association Promoting Geoethics (IAPG) from 2016 (Di Capua et al., 2017), the Code is built upon four titles: a) Professional and scientific work; b) Geosciences and its relationship with society; c) Geosciences and its relationship with the environment; and d) Contribution to new generations of scientists and professionals in Geosciences.

The construction strategy of the Code underscores the pivotal role of the Chilean geoscientist community. Thus, the Code proposal was enriched through consultations, including surveys, meetings, discussions, and seminars, engaging the Geoscientist Community of Chile to understand their perspectives on pertinent topics and challenges. Furthermore, consultations and reflections were conducted to validate the Code proposal before and during the XVI Chilean Geological Congress in 2023. Ultimately, the Code underwent validation with experts from the IAPG, including geoscientists representing Latin America. Consequently, the Code authentically represents the concerns and challenges of the national geoscientific community while also resonating with the international geoscientific community.

Financing

This project is sponsored by the Geological Society of Chile.

Acknowledgements

To the geoscientist community of Chile, the IAPG experts and other professionals who have participated in the process of construction and reflection on the titles of the proposed Geoethics Code.

References

Di Capua, G., Peppoloni, S., Bobrowsky, P.T., 2017. The Cape Town Statement on Geoethics. Annals of Geophysics, 60, Fast Track 7: Geoethics at the heart of all geoscience. doi: 10.4401/ag-7553.

Keywords

Geoethics Code, Principles and Values, IAPG, Geoscientist Community.

How to cite: Bobadilla, H., Pinto Lincoñir, L., Ramirez, P., González, T., Benado, J., Lay, N., Villaseñor, T., Valenzuela, M., Alam, M. A., and Pérez, A.: Proposal for a Geoethics Code for the Geoscientist Community of Chile, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6573, https://doi.org/10.5194/egusphere-egu24-6573, 2024.

EGU24-6593 | ECS | Posters on site | EOS4.4

Invitation to a research project on geography and climate education 

Pimnutcha Promduangsri

Educational approaches around the world are shaped by diverse geographical factors, including topography, climate, distance, urbanization and societal characteristics.  As a consequence, the methods employed for climate change education (CCedu) are expected to vary according to these geographical factors.

The United Nations Educational, Scientific and Cultural Organization (UNESCO) emphasizes the crucial role of CCedu in fostering an understanding of and effective response to the impacts of the climate crisis.  The Intergovernmental Panel on Climate Change (IPCC) highlights the importance of a globally conscious population for effectively addressing and adapting to climate change challenges.

However, rather than exploring the concept of CCedu or its effectiveness, my research project will focus on identifying the influence of geographical factors on climate change education/literacy.  In the long run, this project could potentially contribute to improving the effectiveness of CCedu.  I invite participants to visit my poster to discuss, share ideas and collaborate on this research project.

How to cite: Promduangsri, P.: Invitation to a research project on geography and climate education, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6593, https://doi.org/10.5194/egusphere-egu24-6593, 2024.

Environmental (in)justice arising from Climate change and urbanization exhibit uneven distributions, specifically impacting disadvantaged communities. While studies in the USA highlight the elevated heat exposure faced by low-income and ethnic minority groups, similar insights are lacking for other countries. This knowledge gap impedes a comprehensive understanding of environmental (in)justice experienced by various socio-economic and ethnic groups and hampers the identification of inadequacy in urban planning policies.

This research seeks to bridge the gap between social and environmental sciences to address environmental (in)justice by establishing a link between extreme heat (at both regional and country level) and socio-economic disparities for Australia and New Zealand. Using remotely sensed satellite data for Land Surface temperature mapping for summer (night time) and Census data of countries, the analysis explores various socio-economic indicators—such as education levels, age demographics, and the proportion of foreign populations.

Australia and New Zealand serve as pertinent case studies due to their distinct socio-economic landscapes and Indigenous populations. By recognizing the unequal distribution of urban heat and its disproportionate impact on vulnerable communities, there emerges a critical mandate to prioritize equitable urban planning policies. This research underscores the urgency for policymakers and urban planners to prioritize environmental justice interventions and integrate strategies that aim to reduce race and class disparities concerning urban heat. The findings also serve as a template for similar analyses globally; fostering inclusive, equitable and resilient urban landscapes.

How to cite: Chawla, J. and Benz, S.: Examining Race and Class Disparities in Urban Heat in Australia and New Zealand: Towards Environmental Justice in Urban Planning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6662, https://doi.org/10.5194/egusphere-egu24-6662, 2024.

EGU24-7655 | Orals | EOS4.4

Delivering Critical Raw Materials: Ecological, Ethical and Societal Issues 

Richard Herrington and Sarah Gordon

Leaders across geographical and political boundaries are united behind a pledge to deliver a net zero carbon world by 2050.  Society’s conundrum is that mining is an essential part of that delivery, yet is an activity regarded by many as unpalatable. Projects that have fallen short on ecological, ethical, or social grounds, serve to confirm to many that mining is currently not an industry to be trusted, rather than being the industry that could and should be empowering significant societal development.

Examples of societal failure include the incidents around the 2012 miners’ strike at the Marikana platinum mine in South Africa which escalated into violence and loss of life.  Failure on ethical grounds was most recently highlighted by the settlement of corruption claims in the Democratic Republic of Congo (DRC) where international mining company staff bribed country officials to secure “improper business advantages.”  Ecological failures are all too common and most visible in the failure of tailings storage facilities such as the 2015 Mariana (Brazil), 2019 Brumadinho (Brazil), and 2022 Jagersfontein (South Africa) dam disasters.

The challenge for those who explore, extract, and process the raw materials so vital for the energy transition, is to do so whilst delivering on true Sustainability right from the start of any project.  Mining disasters are rarely a surprise.  The proactive management of both threats and opportunities is therefore key to the urgent delivery of materials to secure our net zero future in a responsible manner.  We must ensure that this delivery is achieved by projects with wholly net positive outcomes for the environment and people.

How to cite: Herrington, R. and Gordon, S.: Delivering Critical Raw Materials: Ecological, Ethical and Societal Issues, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7655, https://doi.org/10.5194/egusphere-egu24-7655, 2024.

EGU24-8075 | Orals | EOS4.4

Can landslides provide geosystem services? 

Martin Mergili, Christian Bauer, Andreas Kellerer-Pirklbauer-Eulenstein, Jana Petermann, Hanna Pfeffer, Jörg Robl, and Andreas Schröder

The concepts of biodiversity and ecosystem services, focusing on the diversity of life and the services provided to humans by such diversity, in interaction with abiotic ecosystem components, are well established. Only recently, geosciences have started to challenge this rather biocentric view by highlighting that geodiversity – understood as the diversity of minerals, rocks, geological structures, soils, landforms, and hydrological conditions – provides substantial services to society and should be treated as equal partner to biodiversity. It was proposed to use the more general term natural services or, where geodiversity is much more relevant than biodiversity, geosystem services. Even though the term geosystem services is more and more employed in literature, it evolves only slowly into a commonly used concept with a clearly defined meaning. Interpretations range from all services associated with geodiversity which are independent of interactions with biotic nature, to the restriction to subsurface services. None or few of these concepts, however, include risks as negative services, or as costs of services, which is surprising as this would enable a more integrated vision on human-nature relationships. Only very recently, the potential of geosystem service maps to highlight both services and risks related to geomorphological processes was pointed out.

This work picks up landslides as a type of geomorphological process and landform, which is rather negatively connotated in society and associated with risks rather than with chances. We use landslides to develop a broader understanding of geosystem services, together with the common understanding of hazards and risks. We will (i) present a sound and integrated conceptual framework to consider landslides within the field of tension between risks and resources, and (ii) highlight a case study where landslides are used as cultural geosystem services for environmental education in the context of UNESCO Global Geoparks, which are considered important instruments for conserving and promoting geodiversity.

How to cite: Mergili, M., Bauer, C., Kellerer-Pirklbauer-Eulenstein, A., Petermann, J., Pfeffer, H., Robl, J., and Schröder, A.: Can landslides provide geosystem services?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8075, https://doi.org/10.5194/egusphere-egu24-8075, 2024.

EGU24-10646 | Posters virtual | EOS4.4

Protects and Heats 

Walter Tavecchio

The project “Protects and Heats” aims to safeguard the environment, to reduce the carbon dioxide emissions and the risk of collapse of buildings affected by earthquakes.

This is a new way to heat and cool buildings and at the same time mitigate the seismic vibrations.

 

The logic of the project is to create a discontinuity (Moat) in the ground in front of the structures to be protected, similar to damping methods that are implemented to dampen the vibrations produced by mechanical machines and without compromising the stability of the buildings themselves.

The project involves the construction of a double row of aligned micro piles and the insertion of HDPE and steel pipes inside the vertical drilling holes.

Closed circuit geothermal probes will be positioned, inside some vertical holes, with a low enthalpy closed circuit geothermal system.

The method of the project is achieved by combining two types of technologies:

-   The first concerns the interposition, between the direction of the seismic waves and the buildings, of a damping barrier.

The vertical barrier starting from the topographic surface will be positioned outside the buildings, generally orthogonal to the direction of the seismic waves.

-  The second concerns the installation of geo-exchange pipes, in the holes.

How to cite: Tavecchio, W.: Protects and Heats, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10646, https://doi.org/10.5194/egusphere-egu24-10646, 2024.

EGU24-12918 | Orals | EOS4.4

The most consequential ethical decision for geoscience  

Emlyn Koster and Philip Gibbard

A geological definition of the Anthropocene, shorthand for humanity’s cumulative disruption of the Earth-Human Ecosystem, looms as the planet-and-people focused UN approaches its Summit of the Future in New York City on 22-23 September 2024. The International Union of Geological Sciences (IUGS) “aims to promote development of the Earth sciences through the support of broad-based scientific studies relevant to the entire Earth system”. With the UN recently declaring that the planet is in peril and in need of a rescue plan, Anthropocene considerations with a geoethical lens are urgently needed.

Each potential new interval in the Geological Time Scale begins with a working group mandated by the International Stratigraphic Commission (ICS), in the case of the Anthropocene also by its Subcommission on Quaternary Stratigraphy (SQS). The Anthropocene Working Group (AWG) was formed in 2009. In 2010, its first chair Jan Zalasiewicz with co-authors Mark Williams, Will Steffen and Paul Crutzen recognized that “the Anthropocene represents a new phase in both humankind and of the Earth, when natural forces and human forces become intertwined, so that the future of one determines the fate of the other”. In 2015, the AWG’s second and current chair Colin Waters with ten co-authors posed the question "Can nuclear weapons fallout mark the beginning of the Anthropocene Epoch?" in the Bulletin of the Atomic Scientists. This was affirmed in 2019 and the AWG presented its recommendation to the SQS in early 2024. The remaining review and decision steps are the ICS and IUGS. Reflecting concerns of other geoscience scholars as well as of other professions and an anxious public, an opposing mindset advocates for an Anthropocene event that spans the cumulative and ongoing environmental impacts of Homo sapiens. It views Geological Time Scale protocols as unsuitable for archaeological and contemporary developments, regards unemotive references to humanity’s most abhorrent invention as distasteful, and visualizes the Anthropocene Event as valuably informing a new zeitgeist for our troubled world.

In 1950 astronomer Fred Hoyle anticipated that humanity’s first view of the Earth from space would revolutionize the course of history. Insofar as a ‘giant leap of mankind’ did not result from NASA’s Apollo 1969 lunar mission with its estimated 600 million viewers, the Anthropocene Event fuels an opportunity for geoscience to inform a realistic outlook during NASA’s upcoming Artemis lunar mission. With unique knowledge of once pristine environments, current climate change and incipient sea level rise, ongoing biodiversity loss and ecosystem disruption, finite energy and mineral resources, the geoscience profession should arguably have already become a crucial asset in this troubled world.

How to cite: Koster, E. and Gibbard, P.: The most consequential ethical decision for geoscience , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12918, https://doi.org/10.5194/egusphere-egu24-12918, 2024.

EGU24-13965 | Orals | EOS4.4

Ocean Futures: A New Paradigm and Teaching in the Age of Ocean Change 

Susanne Neuer, Stephanie Pfirman, Roberta Martin, Katie Kamelamela, Amy Maas, and Nick Bates

The new School of Ocean Futures (oceans.asu.edu) at Arizona State University (Tempe, AZ, USA) has embarked on a novel way of teaching ocean science with a forward-looking philosophy that centers on the current and future states of the ocean. While situated in Arizona State University’s main campus, it leverages the location of its two offshore campuses, the Center of Global Discovery and Conservation Science in Hilo, Hawaii, and the Bermuda Institute of Ocean Sciences (BIOS) in Bermuda. The Ocean Futures programs combine aspects of traditional ocean science teaching with ocean stewardship, partnerships, and Indigenous knowledge, and focus on the communities that live with the ocean and are affected by its rapid change. In this presentation we will introduce the curriculum of the new degree, as well as the challenges encountered, and best practices learned. Novel courses include “Introduction to Ocean Futures”, a capture course that aims at increasing the interdisciplinary knowledge of oceans, while actively seeking to increase diversity and retention in the field via inclusive pedagogical practices, the historical context of oceanography and an emphasis on developing a mindset of empowerment for change. It is followed by “Ocean Communities”, a course that immerses students through an ethnobotanical lens in global mountain to ocean cultural connections, while elaborating on how various human communities engage, exchange, and build relationships with regional resources. The students will receive hands-on aquatic knowledge through field courses at BIOS, the Sea of Cortez, Hawaii, and Antarctica. The curriculum culminates with an ocean workshop and capstone course that will allow the students to work directly with partners to address real-world challenges facing coastal communities and marine systems.

 

 

How to cite: Neuer, S., Pfirman, S., Martin, R., Kamelamela, K., Maas, A., and Bates, N.: Ocean Futures: A New Paradigm and Teaching in the Age of Ocean Change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13965, https://doi.org/10.5194/egusphere-egu24-13965, 2024.

In the Anthropocentric era, the human-driven climate crisis has become a serious global issue. To mitigate the impacts of climate change, it is crucial for humans to adopt a more sustainable way of living. Human behaviors are shaped by their culture, where religious beliefs play important roles. As a result, people turned to religions for addressing with climate change issues.

Seeming to be unrelated, religions and climate issues have found connections through social systems and communication. By endowing climate issues with religions meanings, religions are able to resonate with the ecological crisis and take meaningful actions. Through this "resonance," religions contribute to climate issues by shaping worldviews, establishing sustainable habits, initiating actions, and influencing policies.

Religious communities have recognized the severity of the human-driven climate crisis. Their call for action reflects the fact that Taiwanese society has failed to respond to the climate crisis due to its endless pursuit of consumerism. To deal with the challenges, religious communities have advocated for “Ecological Conversion”, which persuade people to save the nature for the sake of God.

How religions can empirically contribute to environment issues has been a long-discussed topic. However, previous literatures only focus on the Western-Christian World. Countries with religious beliefs other than Judeo-Christian ethics are seldom discussed. To explore the relationship between religion and climate in Asian contexts, this research will focus on Taiwan, a multicultural country with various religions.

Using the sample data from the 2020 Taiwan Social Change Survey, this study aims to explore the relationship between religion and climate by conducting factor analysis and ordinary least squares regressions.

The evidence reveals a weak connection between religions and people's climate attitudes in Taiwan. Among all the religions in Taiwan, Buddhists and Christians tend to have the most eco-friendly attitudes. The social networks within these two religious communities foster an eco-friendly atmosphere, which highlights the importance of environmental conservation. However, when it comes to peoples’ willingness to pay, faith holders are less likely to show their supports.

By illustrating the religion-climate relationship in Taiwan, this study demonstrates how these two fields intersect in a non-Western society. It also provides implications for how religions can inspire people's willingness to engage in environmental conservation efforts.

How to cite: Tsui, C. H.: Do religions matter? The empirical study of the religion-climate relation in Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14027, https://doi.org/10.5194/egusphere-egu24-14027, 2024.

EGU24-14752 | Posters on site | EOS4.4

Towards sustainable management of georesources: the importance of Cooperation Projects to boost education on responsible and sustainable mining. The example of the SUGERE and GEODES projects. 

Giovanna Antonella Dino, Susanna Mancini, Dolores Pereira, Manuela Lasagna, Francesca Gambino, Guido Prego, Domingos Gonçalves, Aida Jacinto, Daud Jamal, Josè Loite, Hélio Nganhane, Nelson Rodrigues, and Pedro Dinis

Sustainable and responsible management of geo-resources requires a rethinking and redesign of our production and consumption patterns. Awareness of the natural environment as a common good to be preserved, and knowledge of the close link between the natural environment and the socio-economic system are prerequisites for a profound change in human attitudes at both individual and societal levels. In this context, training and education of all actors involved in the management of geo-resources is an indispensable starting point for the acquisition of critical, ethical, and conscious thinking and the technical skills necessary to solve local problems and initiate sustainable development.

The present research focuses on two consequential ERASMUS+ projects: SUGERE and GEODES. Both had the common goal of the international standardization of Higher Education training and teaching in Earth Sciences and Mining Engineering.

SUGERE (Sustainable Sustainability and Wise Use of Geological Resources) was successfully completed in September 2023, involved 3 European universities (from Portugal, Spain, and Italy) and 6 non-European universities (from Mozambique, Cape Verde, and Angola). The objective was to enhance capacity building for the responsible and sustainable use of geological resources by supporting the didactic organization and standardization of 5 degree courses at Bachelor, Master and Doctorate levels in Earth Sciences and Mining Engineering. Both online and face-to-face training sessions were organized in European and African universities.

GEODES, started in June 2023, represents the continuation of the SUGERE project and involves a total of 9 partners. The same 3 European universities and 6 African institutions, formally attributing teaching and training roles to 2 universities that participated in SUGERE, already achieved a good standard in terms of infrastructures and have long teaching experience in the field of geosciences, and receiving 4 young institutions from less favored regions of Angola and Mozambique.

SUGERE and GEODES projects aim to strengthen the role of geosciences in the development of up-to-date strategies for the sustainable management of natural resources and to implement new collaborations thanks to an international network focused on local economic and social development and respect for the natural environment in the geological-mining context. The culture of sustainability and the deepening of skills in the field of geological mining form the basis for the development of the critical thinking necessary for local problem solving, the acquisition of ethical values and the technical skills that underpin sustainable development.

Deepening technical skills in geomining from a sustainable perspective is crucial for developing critical thinking and acquiring ethical values necessary for solving local problems. SUGERE and GEODES contribute to this outcome with a solid network of research, training, sharing and exchange of expertise and research activities between European and non-European universities interested in mining issues. A careful analysis of the local economic development of the countries involved in the projects is required to achieve the most effective methods for the exploration and sustainable exploitation of underground georesources.

 

How to cite: Dino, G. A., Mancini, S., Pereira, D., Lasagna, M., Gambino, F., Prego, G., Gonçalves, D., Jacinto, A., Jamal, D., Loite, J., Nganhane, H., Rodrigues, N., and Dinis, P.: Towards sustainable management of georesources: the importance of Cooperation Projects to boost education on responsible and sustainable mining. The example of the SUGERE and GEODES projects., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14752, https://doi.org/10.5194/egusphere-egu24-14752, 2024.

Since time immemorial, nature, and by extension the ocean, have made positive contributions to the health of mankind. Whether it be fertile soil, pollination, medicine, taking part in mindfulness activities, or food, we as a species depend on the many services provided by the natural world.  Our environment can be linked to some fundamental determinants of health, such as clean air, clean water, and balanced nutrition, and emotional wellbeing.  Therefore, any environmental degradation as a result of climate change has undeniable tangible and intangible effects on human health all over the globe, and this is especially true in relation to mental health in populations occupying Large Ocean Island States (LOIS).   As climate change has led to an increase in extreme weather events, and the accompanying devastation, there has been a corresponding decrease in health and quality of life.  This presentation will explore how the impact of climate change and its corresponding impact on the ocean has enduring impacts, both physiologically and mentally.   Therefore, all of the processes and recommendations to combat climate
change will have important co-benefits to mental and physical health, and help to build resilience in the face of the dearth of resources faced by LOIS. This lack of resources must be urgently addressed, and solutions can be explored by fostering collaboration between mental health professionals and climate scientists to collect sufficient data. The resulting findings can be used to expedite access to the funds needed to implement the necessary levels of mitigation and adaptation specifically tailored to the infrastructural realities of LOIS.

How to cite: Alvarez de la Campa, S.: Climate Change, Ocean Health and Quality of Life - An Inextricable Connection in Large Ocean Island States, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16730, https://doi.org/10.5194/egusphere-egu24-16730, 2024.

EGU24-17346 | Posters on site | EOS4.4

The importance of making geoethics a central concern of Sri Lankan education strategy 

Giuseppe Di Capua and Udaya Gunawardana

Like numerous regions worldwide, Sri Lanka faces significant environmental challenges that endanger its biodiversity, natural resources, and the well-being of its population. Predominant issues encompass water and air pollution, land degradation, deforestation, improper waste disposal, consequences of climate change, disaster risks, as well as the loss of biodiversity and geodiversity. The nexus between political, economic, and social factors contributes to these geo-environmental challenges, often exacerbated by the politicization of the environmental issues in Sri Lanka. However, it is crucial to acknowledge that human activities primarily drive these conditions. Gunnar Myrdal’s Soft State theory asserts that despite the existence of multiple governing bodies, regulations, and laws, humans strategically transcend the environment leading to the depletion of geo-environmental resources within a context of strong societal inequalities, particularly in developing countries influenced by the historical conditioning of colonial interests by developed nations. A philosophical exploration of this issue emphasizes the pivotal role of human indifference towards the environment and natural resources in causing these challenges. To address this issue effectively, a transformation in people's attitudes is imperative, and education emerges as the most potent tool for this purpose. However, a careful analysis of Sri Lanka's primary and secondary school curricula reveals an absence of a dedicated discipline addressing the philosophical and social dimensions of the geo-environmental matter. In light of this, the incorporation of subjects such as geoethics, which specifically addresses the ethical problems in the human-environment interaction, becomes paramount. Integrating geoethics into the educational framework, particularly at primary and secondary levels, stands as the foundation of a sustainable and responsible strategic approach to many societal and environmental problems. This educational strategy should envision as the most important solution to mitigate the majority of geo-environmental problems in Sri Lanka, fostering environmentally sensitive and responsible citizens.

How to cite: Di Capua, G. and Gunawardana, U.: The importance of making geoethics a central concern of Sri Lankan education strategy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17346, https://doi.org/10.5194/egusphere-egu24-17346, 2024.

EGU24-17614 | Orals | EOS4.4

Choice Question (MCQ) Peer Construction for Training Students as Climate Change decision-makers or Knowledge Spreaders 

Gérard Vidal, Charles-Henri Eyraud, Carole Larose, and Éric Lejan

After more than 40 years of reasoned alerts from the scientific community directed towards society, with minimal impact, a recent surge in the size and frequency of extraordinary climatic events has begun to reshape the perspectives of ordinary citizens. This situation underscores the challenge of directly influencing society with scientific evidence or models, emphasizing the crucial role of universities in training students who will occupy intermediate or elevated positions that may impact society at large.

While "Climate Fresk" has gained widespread popularity in higher education institutions as an effective tool for raising awareness about climate change and the intricate processes affecting our global earth ecosystem, concerns have arisen at the university level. The repetition of "Climate Fresk" or similar tools may be perceived as greenwashing practices, as university students are already well-acquainted with the issue. Hence, there is a need to surpass mere awareness in higher education.

As TASK Change Leaders at ENS-Lyon, we explored pedagogical and assessment tools provided by Sulitest. This initiative, extends beyond climate and ocean changes, it places a significant emphasis on various topics, including Sustainable Development Goals, earth limits, and driving processes of climate change. One of the major interest of the approach is to address all disciplines (scientific or non scientific).

We built a three-step strategy involving:

  • Administering a positioning test to enable students to assess their performance relative to the institution and the wider community.

  • Utilizing the looping tool from Sulitest, wherein small teams of students generate Multiple Choice Questions accompanied by a list of academic publications validating the terms of their questions. Subsequently, these questions are discussed in large interdisciplinary open groups, compelling students to articulate questions and answers intelligible across all disciplines.

  • Participating in the TASK to receive an assessment of their proficiency in sustainable development, evaluated by an external body.

This strategy, particularly the second step, empowers students to assume the role of a teacher or knowledge spreader in the face of a diverse peer community. It serves as a simulation of their potential future roles as educators, knowledge spreaders or decision-makers, instilling an understanding of the importance of providing validated sources and the challenges associated with crafting questions and answers comprehensible to all, preparing them for future teaching or decision-making scenarios. A notable byproduct is the creation of valuable pedagogical resources in a "connectivist MOOC flavor."

Beyond the training benefits, membership in the TASK Change Leaders group provides opportunities for discussions on the sustainability of education, green education, and competency frameworks, to apply to ourselves the concepts we are teaching.

How to cite: Vidal, G., Eyraud, C.-H., Larose, C., and Lejan, É.: Choice Question (MCQ) Peer Construction for Training Students as Climate Change decision-makers or Knowledge Spreaders, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17614, https://doi.org/10.5194/egusphere-egu24-17614, 2024.

EGU24-20953 | Posters on site | EOS4.4

Shaping Thriving Ocean Futures – Education to advance healthy coastal communities and marine systems 

Susanne Neuer, Stephanie Pfirman, Roberta Martin, Katie Kamelamela, Amy Maas, Andrew Peters, and Nick Bates

The new Ocean Futures program at Arizona State University (Tempe, AZ, USA) prepares students to become coastal and marine stewards, community leaders, innovators, and researchers capable of shaping the future of the world's oceans.  The program is taught and mentored by faculty and community leaders in an environment that supports our students’ individual and collaborative strengths, creativity, and diversity.  Students learn and work across disciplines, exploring global and local ocean dynamics, ecosystems, and stressors, engaging with community contexts and livelihoods, and advancing culturally-appropriate, reciprocal stewardship.  In support of ASUʻs mission of embeddedness and linking innovation to public value, graduates of the School of Ocean Futures are equipped with the knowledge and skills to work with diverse communities and partners to create innovative solutions for our changing world.

The School of Ocean Futures educational goal is to build student capacity to apply knowledge of coastal and marine systems coupled with community partnerships to help shape thriving futures, both locally and globally.  Students engage in research and work with partners in Arizona, the Bermuda Institute of Ocean Sciences (BIOS) in Bermuda, the Center of Global Discovery and Conservation Science in Hilo, Hawaii, the Sea of Cortez, and Antarctica.

Ocean Futures education at ASU is based on an innovative “cascade” curriculum.  The cascade starts with core classes in Introduction to Ocean Futures and Ocean Communities, followed by foundational courses in sciences and mathematics, an upper-level core class in Oceanography, electives focused on partnerships, stewardship, and advanced problem-solving, and culminates in an applied workshop and capstone course where students work with partners to transfer knowledge to action in addressing problems facing coastal communities and marine systems.

How to cite: Neuer, S., Pfirman, S., Martin, R., Kamelamela, K., Maas, A., Peters, A., and Bates, N.: Shaping Thriving Ocean Futures – Education to advance healthy coastal communities and marine systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20953, https://doi.org/10.5194/egusphere-egu24-20953, 2024.

Fifty years ago, Peter Berg developed a way to locate yourself within your bio-region, starting with your watershed. To begin, trace your water from precipitation to tap—and back to precipitation. Then, how much rain fell in your area last year? How much water does your household consume per month? What percentage of your town’s water supply goes to households? to manufacturing? to farming? to golf courses? to mining operations? to extinguishing fires? What pollutants affect your water supply? Once you can map your local water supplies, consider how manufacturing transistors, operating data storage centers and streaming videos impact international waters. With awareness of our daily lives’ impacts on local and international waters, we can create realistic limits.  

How to cite: Singer, K.: Mapping water from our tap to the watershed: A first step toward ecological limits  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21221, https://doi.org/10.5194/egusphere-egu24-21221, 2024.

This ongoing project integrates the concept of science diplomacy, conducting an in-depth exploration of the intricate interrelations among geo-bio-cultural diversity and its pivotal role in peace building, risk management, and climate action in Colombian cities and territories. Leveraging geodiversity assessment and its correlation with biodiversity, we explore how the bio-geo duplex interacts with ethnic diversity in Colombia. The aim is to develop initiatives aligned with the ancestral knowledge of indigenous, African-descended, farmers, and mixed-Colombian communities across cities and territories withing the geoethics concept.
In the realm of science diplomacy, our emphasis lies in cultivating international collaboration and knowledge exchange to tackle intricate societal challenges. We seek to foster dialogue and cooperation among traditional and nontraditional actors, advocating for the integration of scientific expertise with local and indigenous knowledge. The study provides a comprehensive analysis, considering historical, environmental, economic, social, and political contexts. It sheds light on how these interactions unfold and their diverse representations across Colombia, including the Caribbean, Pacific, and Andean regions.

How to cite: Marin-Ceron, M. I.: Science Diplomacy with Nontraditional Actors: Enhancing Geo-Bio-Cultural Diversity in Colombian Cities and Territories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22117, https://doi.org/10.5194/egusphere-egu24-22117, 2024.

ERE2 – Renewable energy

EGU24-195 | ECS | Posters on site | ERE2.1

An observational study on the microclimate and soil thermal regimes under solar photovoltaic arrays 

Junqing Zheng, Yong Luo, Rui Chang, and Xiaoqing Gao

The high demand for low-carbon energy sources to mitigate climate change has prompted a rapid increase in ground-mounted solar parks. The implementation of photovoltaic (PV) significantly impacted the local climate and ecosystem, which are both poorly understood. To investigate the effects of a typical solar park on the Gobi ecological system, local microclimate and soil thermal regimes were measured year-round under and between PV arrays, at an applied solar park sited in Xinjiang, China. Our results demonstrated their seasonal and diurnal changes. Under solar PV arrays, the mean annual net radiation and wind speed decreased by 92.68% and 50.53% respectively. In contrast, PV panels caused an increase of the rear sides air by 10.12% with 0.87°C. South-facing PV panels reduced wind speed with the prevailing northerly wind below. In addition, the relative humidity rapidly decreased when snow covered the ground, but slightly increased from April to September. We found the soil under PV panels was cooler and tended to be a sink of energy during spring and summer whereas was more often a source during autumn and winter compared with the soil between PV panels. Observed data developed the understanding of the energy processes of solar parks in Gobi ecosystems and provided evidence to support the sustainable management of the solar park.

References:

Zheng, J., Luo, Y., Chang, R., and Gao, X., 2023. An observational study on the microclimate and soil thermal regimes under solar photovoltaic arrays. Solar Energy. 266, 112159.

How to cite: Zheng, J., Luo, Y., Chang, R., and Gao, X.: An observational study on the microclimate and soil thermal regimes under solar photovoltaic arrays, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-195, https://doi.org/10.5194/egusphere-egu24-195, 2024.

Wind resource assessment studies over large regions provide the basis for the preliminary identification of locations with promising wind energy prospects. In past studies, several authors have mapped the mean wind speed across large regions using spatial interpolation methods or machine learning models. In recent studies, more emphasis has been placed on mapping the entire wind speed distribution to evaluate the wind resource variability at unsampled locations. Most of these studies have assumed that the wind speed distribution across the entire region belongs to a single family of probability distribution functions and then processed to map the distribution parameters. A flexible non-parametric approach for wind speed distribution mapping is proposed in this study. The new approach is based on mapping various wind speed quantiles at some fixed percentile points in the region using a machine learning model. Then, at any unsampled location, these quantiles are used as input of an asymmetric kernel estimator of cumulative distribution function to recover the whole wind speed distribution. Asymmetric kernel estimators solve the probability leakage problem that appears when fitting symmetric kernels to bounded variables such as wind speed. The non-parametric approach for wind speed distribution mapping was more effective than a traditional approach based on mapping the parameters of a distribution function. In the best scenario, an improvement was observed between 6% (test samples) and 9% (cross-validation) of the Kolmogorov-Smirnov statistic between the observed and estimated wind speed distribution. The non-parametric approach is recommended for regions with highly variable wind regimes that cannot be captured by a single family of distribution functions.

How to cite: Houndekindo, F. and Ouarda, T.: Mapping wind speed distribution across large regions using machine learning and asymmetric kernel estimators., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1432, https://doi.org/10.5194/egusphere-egu24-1432, 2024.

EGU24-1609 | Orals | ERE2.1

SHIRENDA: A long-term high-resolution database of electricity demand and wind, hydro and PV renewable resources for Spain 

David Pozo-Vázquez, Guadalupe Sánchez-Hernandez, Antonio Jiménez-Garrote, Miguel López-Cuesta, Inés Galván-León, Ricardo Aler-Mur, Joaquín Tovar-Pescador, José Antonio Ruiz-Arias, and Francisco Santos-Alamilllos

Renewable energies (RES) will play a central role in national energy systems worldwide in the near future, boosted by the climate change issue and the ever-growing competitiveness of these energies. An example is the Spanish roadmap to produce 80% of its electricity from renewables by 2030.
However, the transition from the current generation mix to decarbonized energy systems is a formidable challenge, as they must be technically reliable and economically viable. To design such systems, the spatial and temporal variability of RES, combined with proper simulation tools, are determinant. In recent decades, energy system models have emerged as valuable tools for conducting these analyses. These models allow, for a specific region, the analysis of the optimal allocation and sizing of new renewable plants, taking into account the variability of generation and demand, energy costs, integration and the issue of transmission. The key input to these models is a database of RES resources in the study region. However, in many cases, the extent to which these databases represent the actual RES for a given country is far from optimal, reducing confidence in the results. In general, current RES databases face two main problems: 1) low reliability of energy estimates and 2) lack of adequate spatial and/or temporal resolution. In most cases, these problems arise from the lack of actual measurements for model training and validation.
In this work, we present SHIRENDA (Spanish High-resolution Renewable ENergies and Demand database), an enhanced open access database of Spanish renewable energies resources and demand. The database consists of hourly values of wind, solar photovoltaic and hydroelectric capacity factors (CF), together with electricity demand, covering the period 1990-2020, for each of the Spanish NUTS3 regions, which is an unprecedented spatial resolution so far. CFs and demand values were derived using state-of-the-art machine learning models based on: 1) actual values of installed RES capacities (Jiménez-Garrote et al, 2023); 2) real energy and demand data derived from the Spanish TSO and 3) meteorological data derived from the ERA5 reanalysis. The database covers the period 1990-2020, with the period 2014-2020 used for model training and validation purposes.
The SHIRENDA database has been developed within the framework of the MET4LOWCAR project, funded by the Government of Spain, and aims to gather the desirable characteristics to carry out reliable studies on modeling and analysis of energy systems, thus contributing to an adequate energy transition. Notably, the high spatial resolution allows the very high spatial variability of RES resources in the study region to be properly taken into account. At the same time, the high temporal resolution, along with the temporal coverage, allows for properly assessing the impact of climate variability, extreme meteorological conditions and compound events in a future decarbonized energy systems in Spain. 

 

Reference: Jimenez-Garrote et al, 2023. https://doi.org/10.1016/j.solener.2023.03.009

How to cite: Pozo-Vázquez, D., Sánchez-Hernandez, G., Jiménez-Garrote, A., López-Cuesta, M., Galván-León, I., Aler-Mur, R., Tovar-Pescador, J., Ruiz-Arias, J. A., and Santos-Alamilllos, F.: SHIRENDA: A long-term high-resolution database of electricity demand and wind, hydro and PV renewable resources for Spain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1609, https://doi.org/10.5194/egusphere-egu24-1609, 2024.

In June 2023 Swiss people voted a new climate law that set a net-zero emission goal to be reached by 2050 via a full energetic transition from fossil fuels to renewables. The country’s Energy Strategy estimates that 7% (4.3 TWh) of future total renewable energy will be supplied by wind turbines, which requires an increase in the number of installed devices from the 37 currently operating to 760. Such an objective presents numerous challenges as available space is limited by technical restrictions, the country’s complex terrain, and competition with other types of land use.

Thanks to qualities like small size and weight, low noise emission levels, and the ability to operate with winds blowing from any direction at relatively low speed (> 2 m/s), vertical axis wind turbines (VAWTs) installed in urban areas are an attractive alternative to overcome the issues associated with large wind farms. Despite this, the potential for wind energy micro-generation in complex urban settings remains largely unexplored.

Private households use one third of all energy consumed in Switzerland, and residential renewable energy generation currently consists almost exclusively of photovoltaic (PV) panels which, in 2021, represented 78% of all solar systems operating in the country. No similar statistics are available for residential wind energy generation. Even in the scientific literature, current understanding of the interaction between wind and urban areas is limited, and the knowledge about urban wind resources is markedly inadequate to address the challenges posed by climate change to both local and global energy sectors.

Here we use use the Weather Research and Forecast (WRF) model to simulate mean near-surface wind speed over the cities of Lausanne and Geneva to assess the potential for wind energy generation. We perform simulations at 300 m grid spacing and across 85 vertical model levels, with hourly output interval throughout one entire year to identify diurnal and seasonal wind speed trends. We then use power curves of select VAWTs to translate mean wind speed data into potential electrical output maps and time series, over all model cells classified as urban.  

Our results show that mean wind speed is generally higher in Lausanne than in Geneva, especially at nighttime. Diurnal cycles evolve markedly differently between the two cities, although differences are at times minimized due to seasonal changes. The average potential for wind energy harvesting using VAWTs in urban environments varies with turbine size and geographical area. The average daily total energy generation potential is one order of magnitude greater in Lausanne compared to Geneva. In Lausanne, top generation is expected during the nighttime across most months, allowing for a good integration of photovoltaic generation. The opposite happens in Geneva where already lower peak wind speed, and associated energy generation, always culminate during the afternoon.

This research highlights the potential for urban wind energy micro-generation, drawing attention to the role of regional differences and the need and the importance of numerical simulations for quantitative assessments at the city and regional scales.

How to cite: Brandi, A. and Manoli, G.: Numerical assessment of urban wind energy micro-generation potential: a comparison between two Swiss cities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1770, https://doi.org/10.5194/egusphere-egu24-1770, 2024.

Short-term solar irradiance forecasts are becoming increasingly important as power grid operators have to deal with the uncertainty in incoming surface solar irradiance (SSI) and the expected photovoltaic (PV) power production. Geostationary satellites are an excellent source of spectral imagery of SSI-relevant atmospheric components over large geographical regions. The spectral measurements of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the geostationary Meteosat Second Generation satellite form the basis of many SSI estimation and forecasting techniques [3], [4], [6]. These forecasting techniques usually rely on level 2 products to estimate SSI from reflectance but this induces a significant delay in the forecasting cycle. We demonstrate that using a deep learning regressor to estimate surface solar irradiance can drastically reduce this delay.

Previous machine learning-based methods for estimating SSI from geostationary reflectance imagers show great promise and can outperform state-of-the-art radiative transfer retrieval methods at the ground stations used as training sites [1], [2], [5]. Previous methods only use ground station SSI to train on, but point-wise estimators trained on a group of ground stations do not generalize well to out-of-sample ground stations, possibly because of changes in surface albedo [5].

To improve the generalization, we introduce a deep learning spatial convolution operator which is trained to emulate radiative-transfer SSI retrievals from spectral satellite imagery. Our SSI estimator model is fine-tuned on an extensive network of ground stations as a second training set. In this contribution, we will demonstrate the performance of the radiative transfer emulator, its applications and latency based on independent measurements from ground stations across Europe.

 

References
[1] H. Jiang, N. Lu, J. Qin, W. Tang, and L. Yao, “A deep learning algorithm to estimate hourly global solar radiation from geostationary satellite data,” Renewable and Sustainable Energy Reviews, vol. 114, p. 109 327, Oct. 1, 2019, ISSN: 1364-0321. doi: 10.1016/j.rser.2019.109327.
[2] D. Hao, G. R. Asrar, Y. Zeng, et al., “DSCOVR/EPIC-derived global hourly and daily downward shortwave and photosynthetically active radiation data at 0.1° × 0.1° resolution,” Earth System Science Data, vol. 12, no. 3, pp. 2209–2221, Sep. 15, 2020, Publisher: Copernicus GmbH, ISSN: 1866-3508. doi: 10.5194/essd-12-2209-2020.
[3] Y. Lu, L. Wang, C. Zhu, et al., “Predicting surface solar radiation using a hybrid radiative transfer–machine learning model,” Renewable and Sustainable
Energy Reviews, vol. 173, p. 113 105, Mar. 1, 2023, ISSN: 1364-0321. doi: 10.1016/j.rser.2022.113105.
[4] Q. Paletta, G. Terren-Serrano, Y. Nie, et al., “Advances in solar forecasting: Computer vision with deep learning,” Advances in Applied Energy, vol. 11,
p. 100 150, Sep. 1, 2023, ISSN: 2666-7924. doi: 10.1016/j.adapen.2023.100150.
[5] H. Verbois, Y.-M. Saint-Drenan, V. Becquet, B. Gschwind, and P. Blanc, “Retrieval of surface solar irradiance from satellite imagery using machine learning: Pitfalls and perspectives,” Atmospheric Measurement Techniques, vol. 16, no. 18, pp. 4165–4181, Sep. 19, 2023, ISSN: 1867-8548. doi: 10.5194/amt-16-4165-2023.
[6] A. Carpentieri, D. Folini, D. Nerini, S. Pulkkinen, M. Wild, and A. Meyer, “Intraday probabilistic forecasts of surface solar radiation with cloud scale-dependent autoregressive advection,” Applied Energy, vol. 351, doi: 10.1016/j.apenergy.2023.121775.

How to cite: Meyer, A. and Schuurman, K.: Predicting surface solar irradiance from satellite imagery with deep learning radiative transfer emulation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2452, https://doi.org/10.5194/egusphere-egu24-2452, 2024.

EGU24-2922 | Posters virtual | ERE2.1 | Highlight

Storm Daria: Societal and energy impacts in northwest Europe on 25-26 January 1990 

Anthony Kettle

Between late January and early March of 1990 Europe was hit by a sequence of severe winter storms that caused significant infrastructure damage and a large number fatalities. The storm sequence started with Hurricane Daria on 25-26 January 1990, which was one of the most serious events of the storm cluster, especially for the UK.  The low pressure centre moved in the west-northwest direction across Ireland, southern Scotland, and northern Jutland before moving further into the Baltic. The strongest winds south of the trajectory path caused significant damage and disruptions in England, France, Belgium, the Netherlands, and West Germany.   Media reports highlighted building damage, interrupted transportation networks, power outages, and fatalities.  There were also a series of maritime emergencies in the English Channel, North Sea, and Baltic Sea.  This contribution takes a closer look at Storm Daria, presenting an overview of meteorological measurements and the societal impacts, followed by an analysis of the North Sea tide gauge network to understand the storm surge and possible large wave occurrences.  The results for Storm Daria are compared with other serious storms of the past 30 years, highlighting similarities and differences in the patterns of storm impact.  Offshore wind energy was at the planning stage in this early period, but onshore wind energy was established in Europe, and the storm is an important case study of extreme meteorological conditions that that can impact energy infrastructure.  The 1990 winter storm sequence was analyzed in detail by the insurance industry because of the large damage costs, and evidence of an emerging climate change contribution was highlighted.

How to cite: Kettle, A.: Storm Daria: Societal and energy impacts in northwest Europe on 25-26 January 1990, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2922, https://doi.org/10.5194/egusphere-egu24-2922, 2024.

EGU24-4688 | ECS | Orals | ERE2.1

Effects of Upstream Obstacles on Energy Production of Solar and Wind Farms 

Abhirup Bhattacharya and Somnath Baidya Roy

Power production from a renewable energy (RE) source such as a wind farm or urban roof-top solar panel installation is highly sensitive to the obstacles around it, particularly those which are in the upstream direction. RE installations can avoid or minimize the effects of obstacles using proper planning. However, obstacles that come up after the plant is operational can lead to significant loss in power production and revenue. In this study we quantitatively explore two common examples – shading effect of neighbouring buildings on roof-top solar plants and wake effects of upstream wind turbines on offshore wind farms.

The first example considers a horizontal solar panel atop an urban building in a relatively congested neighbourhood. We built a model to quantify the shading effects of neighbouring tall buildings on the solar panel. The model calculates the position of the Sun on the celestial dome at every minute with astronomical accuracy. Then the solar irradiance is calculated for a clear-sky environment. After that the shadow profile is calculated and visualized for obstacle buildings with any height and at any distance. And finally, the loss in available insolation and the power production is calculated. The results show significant power loss due to the building shading effect. For example, a roof-top solar panel surrounded by a 20m taller building at 20m distance can reduce power generation by more than 50%.

The second example is where a new wind farm is constructed upstream of an existing wind farm. We used two different models to quantify the meteorological effects of the upstream wind turbines on downwind turbines. The first one involves Jensen Wake Model (JWM), a static wake recovery model to simulate the wake effects of upstream obstacle turbine on downwind turbine. The second approach makes use of the Wind Turbine Parameterization (WTP) in WRF. This method implements wake loss using a wind turbine power curve data and wake recovery through atmospheric vertical mixing. A case study has been conducted for a hypothetical offshore wind farm situated in Palk Strait between India and Sri Lanka by placing wind farms of different shapes and dimensions in the upwind direction. The results show a range of losses in annual power production between 3 – 12 MW, which roughly converts into €1.1M – €4.1M.

This study demonstrates that the effects of upstream obstacles on RE sources are non-trivial and can have serious impacts on the performance on RE installations. Currently, local zoning laws in India and many countries do not protect RE installations from future constructions that can act as obstacles. Hence, effective policies are required to safeguard the return on investments in the RE industry.

How to cite: Bhattacharya, A. and Baidya Roy, S.: Effects of Upstream Obstacles on Energy Production of Solar and Wind Farms, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4688, https://doi.org/10.5194/egusphere-egu24-4688, 2024.

EGU24-4715 | Orals | ERE2.1 | Highlight

Impacts of Air Pollutant Emissions on Solar Energy Generation 

Fei Yao, Paul Palmer, Jianzheng Liu, Hongwen Chen, and Yuan Wang

Particulate matter (PM) in the atmosphere and deposited on solar photovoltaic (PV) panels reduce PV energy generation. Reducing anthropogenic PM sources will therefore increase carbon-free energy generation. However, we lack a global understanding of the sectors that would be the most effective at achieving the necessary reductions in PM sources. We combine well-evaluated models of solar PV performance and atmospheric composition to show that deep cuts in air pollutant emissions from the residential sector substantially benefit Asian PV power output. Specifically, halving residential emissions of PM would lead to an additional 10.3 TWh yr-1 and 2.5 TWh yr-1 of PV energy generation in China and India in 2020, respectively. Compared to the 2020 electricity generation of 261.6 TWh yr-1 and 54.4 TWh yr-1 from solar PV technology in China and India, respectively, these unrealised sources of energy generation represent an improvement of approximately 4-5%. While anthropogenic PM sources originate mainly from producers, they are responding to changes in domestic and international consumer demand. This raises a critical question about the extent to which consumers, who benefit from the emission process, should be responsible for the resulting unrealised, cleaner PV energy generation. Focusing on Northeast Asia (NEA), we investigate the source-receptor relationship of PV energy losses attributable to PM pollution among China, South Korea, and Japan by incorporating a new input-output model into the combined models of solar PV performance and atmospheric composition. Our findings reveal that the solar energy generation losses attributable to PM pollution in NEA caused by emissions produced in China surpass those linked to China’s consumption that stimulates emissions in China and elsewhere, with the disparity amounting to 9.3 TWh yr-1. Conversely, a reverse pattern is observed for solar energy generation losses linked to emissions produced versus induced by consumption in South Korea and Japan, where the disparities are found to be -0.023 TWh yr-1 and -0.231 TWh yr-1, respectively. In other words, when we consider international trade across NEA, we find there is diminished (augmented) responsibility for China (South Korea and Japan) in explaining PV-related energy losses attributable to PM pollution.

How to cite: Yao, F., Palmer, P., Liu, J., Chen, H., and Wang, Y.: Impacts of Air Pollutant Emissions on Solar Energy Generation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4715, https://doi.org/10.5194/egusphere-egu24-4715, 2024.

EGU24-4887 | ECS | Posters on site | ERE2.1

A parameterization scheme for the floating wind farm in a coupled atmosphere-wave model (COAWST v3.7) 

Shaokun Deng and Shengli Chen

Coupling Weather Research and Forecasting (WRF) model with wind farm parameterization can be effective in examining the performance of large-scale wind farms. However, the current scheme is not suitable for floating wind turbines. In this study, a new scheme is developed for floating wind farm parameterization (FWFP) in the WRF model. The impacts of the side columns of a semi-submersible floating wind turbine on waves are firstly parameterized in the spectral wave model (SWAN) where the key idea is to consider both inertial and drag forces on side columns. A machine learning model is trained using results of idealized high-resolution SWAN simulations and then implemented in the WRF to form the FWFP. The difference between our new scheme and the original scheme in a realistic case is investigated using a coupled atmosphere-wave model. Results indicate that the original scheme underestimates the power output of the entire floating wind farm in the winter scenario. On average, the power output of a single turbine is underestimated by a maximum of 694 kW (12 %). The turbulent kinetic energy decreases within the wind farm, with the greatest drop of 0.4 m2 s-2 at the top of the turbine. This demonstrates that the FWFP is necessary for both predicting the power generated by floating wind farms and evaluating the impact of floating wind farms on the surrounding environment.

How to cite: Deng, S. and Chen, S.: A parameterization scheme for the floating wind farm in a coupled atmosphere-wave model (COAWST v3.7), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4887, https://doi.org/10.5194/egusphere-egu24-4887, 2024.

EGU24-4945 | ECS | Orals | ERE2.1

Effect of Rainfall on Evolution of the wind turbine wake:A LES Study 

Xuefeng Yang and Shengli Chen

The rainfall directly affects wind turbine operation by eroding the turbine blades and changing their aerodynamic performance, however, little research has been conducted on the effects of rainfall on wake evolution. The present study simulates the impact of rainfall on wind turbine wake using a coupled LES-ADMR model, in which a double Euler method is employed for the rainfall injection. The numerical simulation results indicate that the rainfall reduces the wake wind speed in the sweep area while increasing it in the outer region of the upper blade tip, reaching up to 2.1% for increment. Rainfall also weakens the turbulence in the near wake and the outer region of the top tip (as much as 2.0%), with the influence extending up to 10 diameters downstream the wind turbine. These modifications are positively correlated with the rainfall intensity and inversely correlated with wind speed. By analyzing the rainfall-induced changes in MKE (Mean Kinetic Energy) and TKE (Turbulent Kinetic Energy) budget terms, the study reveals that the alteration of turbulent radial transport of MKE is the main cause of changes in wind speed, while the variation of shear production of  TKE is responsible for the turbulent intensity changes. The rainfall-induced change of  reynold stress u'w' is the root cause of the above phenomenons.

How to cite: Yang, X. and Chen, S.: Effect of Rainfall on Evolution of the wind turbine wake:A LES Study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4945, https://doi.org/10.5194/egusphere-egu24-4945, 2024.

EGU24-5042 | Orals | ERE2.1

West African operational daily solar forecast errors and their links with meteorological conditions 

Sandrine Anquetin, Léo Clauzel, Christophe Lavaysse, Guillaume Tremoy, and Damien Raynaud

With its commitment to reduce greenhouse gas emissions and harnessing the potential of renewable energy, the West African region is at the forefront of global environmental challenges. This work focuses on the specific aspect of solar energy, which holds significant promise in the region. High quality solar energy forecasts are necessary for solar plants and power systems management, while they remain poorly developed in this region, in particular because of the specificities of the West African climate. We evaluate the errors in Global Horizontal Irradiance (GHI) operational forecast models for two Sahelian solar power plants, Zagtouli in Burkina Faso and Sococim in Senegal, and investigate their links with local meteorological conditions, with a specific focus on clouds and dust aerosols.

This work begins by assessing aerosol products and our results support the use of the CAMS reanalysis for the assessment of Aerosol Optical Depth (AOD), particularly with respect to dust aerosols. We then assess the performance of three operational GHI forecast products: the Global Forecast System (GFS, NCEP/NOAA), the Integrated Forecast System (IFS, ECMWF), and SteadyMet (SM), developed by French company Steadysun, which is computed from the previously mentioned Numerical Weather Prediction (NWP) model outputs. The analysis reveals that IFS and SM outperform GFS in terms of forecast accuracy, with SM showing a slight advantage due to its probabilistic nature, which provides valuable information on forecast uncertainty.

Closer examination reveals a significant relationship between GHI forecast errors and local meteorological characteristics. These errors are more pronounced during the wet season, primarily attributed to cloud occurrence. Dust events are found to play a secondary role, particularly during the dry season. Correlation analyses underline the main link between forecast errors and cloudiness, while co-occurrence analyses highlight the fact that dust aerosol loading is a secondary factor in forecast errors for the GHI directly or for cloud representation (aerosol-cloud interaction).

How to cite: Anquetin, S., Clauzel, L., Lavaysse, C., Tremoy, G., and Raynaud, D.: West African operational daily solar forecast errors and their links with meteorological conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5042, https://doi.org/10.5194/egusphere-egu24-5042, 2024.

EGU24-6578 | Posters on site | ERE2.1

Evaluation of hub-height wind forecasts over the New York Bight 

Timothy Myers, Allison Van Ormer, Dave Turner, James Wilczak, Laura Bianco, and Bianca Adler

As offshore wind energy development accelerates in the U.S., it is important to assess the accuracy of hub-height wind forecasts from numerical weather prediction models over the ocean.  Leveraging approximately two years of Doppler lidar observations from buoys in the New York Bight, we provide an evaluation of 80-m wind speed forecasts from two weather models: the High-Resolution Rapid Refresh (HRRR) model and the Global Forecast System (GFS).  These two models have different horizontal (3 km vs 13 km) grid spacing, vertical layering, initialization methods, and parameterizations of boundary layer mixing and surface-atmosphere interactions.  Even with these differences, the models demonstrate similar and highly skillful short-term forecasts at three measurement sites (Day 1: root mean square error, RMSE, ≤ 2.4 m/s and r≥0.83; Day 2: RMSE≤3 m/s and r≥0.77).  Day-ahead forecasts also exhibit skill (Critical Success Index > ~0.5) in predicting quiescent winds and winds associated with maximum turbine power.  By Day 10, GFS forecasts on average have almost no skill.  Short-term forecast skill by the HRRR and GFS does not strongly depend on season or time of day, yet we find some dependence of the models' performance on near-surface stability.  Additionally, 5-14 day forecasts by the GFS exhibit lower RMSE during summer relative to other seasons.  The high skill of the HRRR and GFS short-term forecasts establishes confidence in their utility for offshore wind energy maintenance and operation.

How to cite: Myers, T., Van Ormer, A., Turner, D., Wilczak, J., Bianco, L., and Adler, B.: Evaluation of hub-height wind forecasts over the New York Bight, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6578, https://doi.org/10.5194/egusphere-egu24-6578, 2024.

EGU24-7587 | Orals | ERE2.1 | Highlight

Replacement of meteorological towers with ground-based remote-remote sensing sodars: How close are we?  

Ebba Dellwik, Sten-Ove Rodén, Johan Arnqvist, Mikael Sjöholm, Corinna Möhrlen, and Andre Gräsman

As wind turbines have grown in size, it has become ever more costly to make the necessary tower-based wind observations needed both for the pre-operation (siting) phase and for wind turbine operations. In response to this challenge, the wind energy scientific community has - over the last decades - focused on evaluating and improving ground-based remote-sensing technology. The development has often been done in close collaboration with the innovative companies dedicated to providing the new solutions for replacing the expensive meteorological towers to the market.

The project EARS4WindEnergy, which started in March 2023, represents one such effort. The project is focused on a re-exploration of the sodar technology, which preceded the later focus on wind lidars. Here, we present a benchmarking of the AQ510 sodar equipped with new signal processing technology with tall-tower data focusing on the three “must-perform” criteria of accurate wind speed, accurate turbulence intensity and a reliable identification of erroneous data. The complementary aspects of data availability and robustness in relation to current wind lidars is also discussed. Most of the presented data are taken at the Østerild test site in Northern Denmark, where a 244m tall tower allows for accuracy quantification over most of the sodar’s measurement range.

How to cite: Dellwik, E., Rodén, S.-O., Arnqvist, J., Sjöholm, M., Möhrlen, C., and Gräsman, A.: Replacement of meteorological towers with ground-based remote-remote sensing sodars: How close are we? , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7587, https://doi.org/10.5194/egusphere-egu24-7587, 2024.

EGU24-7725 | ECS | Orals | ERE2.1 | Highlight

Identifying weather patterns responsible for renewable energy production droughts in India 

Hannah Bloomfield, Kieran Hunt, and Isa Dijkstra

Energy systems across the globe are evolving to meet climate mitigation targets set by the Paris Agreement. This process requires a rapid reduction on nations’ reliance on fossil fuels and significant uptake of renewable generation (such as wind power, solar power, and hydropower). In parallel to the decarbonisation of the electricity sector, both the heat and transport sectors are electrifying to reduce their carbon intensity. Renewable energy sources are weather-dependent, causing production to vary on timescales from minutes to decades. A consequence of this variability is that there may be periods of low renewable energy production, here termed ‘renewable energy droughts’. This energy security challenge needs to be addressed to provide a consistent power supply and to ensure grid stability. India is chosen here as a study area as a region that already has a large existing proportion of renewable generation (42 GW of wind power, 61 GW of solar power and 51 GW of hydropower were installed as of October 2022) and a region that experiences good sub-seasonal predictability in large-scale patterns.

In this study, we use broad variety of data sources to quantify potential and realised capacity over India from 1979 to 2022 using the ERA5 reanalysis and a range of open source renewable energy installation data. Using gridded estimates of existing installed renewable capacity combined with our historical capacity factor dataset, we create a simple but effective renewable production model for each Indian state and at national level. We use this model to identify the timing of historical renewable energy droughts and then discuss potential weaknesses in the existing grid – particularly a lack of complementarity between wind and solar production in north India – and vulnerability to high deficit generation in the winter. The data produced here have all been made open access and the methods could easily be reproduced over any region of interest.

We then consider the weather patterns that could cause the largest renewable energy droughts over India and investigate potential sources of predictability. Existing large-scale daily weather types (based on large-scale wind map clustering) as well as novel patterns created by k-means clustering of more relevant variables for wind and solar power are used to investigate the different weather patterns causing renewable energy droughts. Renewable energy droughts largely occur during the winter season (January and February) and are caused by low seasonal wind speeds in combination with weather patterns bringing high cloud cover. These are mainly winter anticyclones and western disturbances.

Sources of potential sub-seasonal predictability are considered for the largest renewable energy droughts, including the Madden Julian Oscillation and Boreal Summer Intra-Seasonal Oscillation. Although both have a stronger relationship with high energy production days, links between phases of these two modes of variability and renewable energy droughts have been identified. These could help to provide early warnings for conditions that challenge supply security in the future.

How to cite: Bloomfield, H., Hunt, K., and Dijkstra, I.: Identifying weather patterns responsible for renewable energy production droughts in India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7725, https://doi.org/10.5194/egusphere-egu24-7725, 2024.

Long-term wind speed forecasting is still in its early stages, particularly in India. Due to lack of operational forecasts the Indian wind industry is forced to rely on climatological averages, that do not incorporate interannual variability. The overall goal of our study is to evaluate and enhance the capability of the Indian Institute of Tropical Meteorology Coupled Forecast System Version 2.0 (IITM CFSv2) model to forecast the summer monsoon (June-September) 10m wind speeds over India at seasonal scales as a part of the Monsoon Mission III program. The model runs were conducted in hindcast mode for the period 1981-2017. Initially, we conducted a systematic evaluation to assess the quality of the forecasts initialized in February and March for selected stations by comparing them against observations from the Global Summary of the Day (GSOD) dataset. Our findings indicate that the raw forecasts are poor quality with Symmetric Mean Absolute Percentage Error (SMAPE) in the 70% and 90% range.

Next, we developed calibration algorithms using ML techniques to improve the quality of the forecasts. Linear Regression, Random Forest, XGBoost, LSTM, Conv-LSTM, GRU were employed as regression models. The outcomes from the best-performing model demonstrate that calibration significantly enhances the quality of the forecasts. After calibration, the mean absolute error (MAE) values typically fall within the range of 0.5 to 0.9 m/s for most stations, though a few stations exhibit values exceeding 1 m/s, in contrast to the raw forecasts where the error range extends from 1.2 to 2 m/s. The SMAPE is reduced to between 30% and 60% after calibration. When compared with 30-year climatology, the calibrated forecasts in 60% of the stations show a positive Root Mean Square Error Skill Score (RMSESS) ranging from 0.01 to 0.3 whereas the scores for the raw forecasts are showing highly negative skill. This study demonstrates that ML based calibration is a promising technique that can significantly improve the quality of numerical model forecasts and perform significantly better than climatology.

How to cite: Banerjee, R. and Baidya Roy, S.: Long - term wind speed forecasting for the monsoon seasons at station scales over India: Integrating ML and Numerical techniques, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7873, https://doi.org/10.5194/egusphere-egu24-7873, 2024.

EGU24-8687 | Posters on site | ERE2.1

Improvement of Korea Meteorological Administration insolation Information by Applying Detailed Terrain Data 

Jinah Yun, Jinwon Kim, Minwoo Choi, Hee-Wook Choi, Yeon-Hee Kim, Sang-Sam Lee, Ki-Hoon Kim, and Chulkyu Lee

  As the proportion of renewable energy continues to rise, solar energy reaching the Earth's surface holds a significant share compared to other sources such as wind power. Efficient utilization of solar energy necessitates accurate data on surface insolation. Consequently, both domestically and internationally, there's active research into developing insolation mapping using various numerical models based on solar meteorological resources.
The Korea Meteorological Administration's KMAP (Korea-Meteorological Administration Post-processing), hereafter KM, provides insolation data. However, its limitation lies in the inability to realistically account for complex terrains like mountains due to the 1.5 km resolution of the Meteorological Administration's LDAPS (Local Data Assimilation and Prediction System), an operational local forecast model.
 This study analyzes the impact and characteristics of different resolutions of Digital Elevation Models (DEMs) on the accuracy of surface insolation calculations performed by KMAP-Solar, the solar energy mapping system of the Korea Meteorological Administration (1.5 km and 100 m). Comparison and verification against insolation data from 42 Korea Meteorological Administration Automated Synoptic Observation Systems (ASOS) stations reveal that the introduction of high-resolution DEM reduces land-averaged solar radiation biases by up to 32 Wm
−2 at all observation points, particularly accentuating its effect in regions with complex terrains.
The enhanced accuracy due to high-resolution DEMs is attributed to their ability to alleviate errors caused by differences in Sky View Factors (SVF) between high and low-resolution DEMs. Both DEM resolutions exhibit correlations between insolation and terrain elevation (SVF). However, high-resolution DEMs significantly underestimate these relationships compared to low-resolution DEMs, primarily in areas with high elevations where low-resolution DEMs inadequately represent steep terrains and/or small SVFs.
This study demonstrates that high-resolution DEMs provide a more realistic distribution of insolation by integrating a broader range of crucial terrain parameters, thus proving their significance in accurate insolation calculations compared to low-resolution DEMs. It is anticipated that this research will play a crucial role in supporting future solar energy studies, real-time prediction, and management within solar power plant installations and the power grid.

How to cite: Yun, J., Kim, J., Choi, M., Choi, H.-W., Kim, Y.-H., Lee, S.-S., Kim, K.-H., and Lee, C.: Improvement of Korea Meteorological Administration insolation Information by Applying Detailed Terrain Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8687, https://doi.org/10.5194/egusphere-egu24-8687, 2024.

EGU24-8933 | ECS | Posters on site | ERE2.1

An Austrian case study on empowering ReduceData solar power forecasting using a ML-driven semi-synthetic data generator 

Petrina Papazek, Pascal Gfäller, and Irene Schicker

Heterogenous, location dependent solar power/PV installations entail individually different production. This is a challenge for power grid operators as to feed-in PV-production, besides its vast output variability, the grid operators need very high-resolution (temporal and spatial) power forecasts, ideally tailored to each of these sites. Technological advances along with the expansion of solar energy will often modify the initial setup of a production site, thereby significantly altering the production data over their record time. Inevitably inconsistent presentations of historic data or short record periods (e.g.: in case of newly build sites) pose challenges in the renewable sector. This induces a common issue in AI driven post-processing:  machine learning and AI powered forecasts heavily rely on sufficient, consistent historic data, more so if simulating expected production peaks in high temporal resolution is part of the requirements. To address the need of such reduced historic data, we aim at generating semi-synthetic data within the ReduceData project by providing a sufficiently represented and continuous data set across multiple data sources. Building on random forest models, we exploit spatial and temporal strongly associated non-reduced auxiliary data, such as satellite data products (e.g.: CAMS) and reanalysis fields (e.g.: ERA5).  Due to their limited nature, PV production records and high-resolution numerical models (e.g.: AROME) will be targeted by our semi-synthetic data generator. The presented case study focuses on nowcasting- to short-range forecasts in 15-minute update frequency tailored to selected solar power production sites in East-Austria. We study to what extent deep learning methods benefit from a consistent semi-synthetic data set built on different raw data sources, highlighting the added value of combining various sources via deep learning. Inputs for the AI-driven post-processing are, for instance, the climatology of satellite data and reanalysis, pvlib’s estimations, AROME surface parameters, and in-house nowcasting models (e.g.: IrradPhyD-Net). Different settings of the semi-synthetic data generator are evaluated by cross-validation. In most studied cases, we achieve a high skill compared to available classical and standard methods (e.g.: persistence, climatology). 

How to cite: Papazek, P., Gfäller, P., and Schicker, I.: An Austrian case study on empowering ReduceData solar power forecasting using a ML-driven semi-synthetic data generator, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8933, https://doi.org/10.5194/egusphere-egu24-8933, 2024.

To improve the process of solar energy production, we can utilize the downward
shortwave flux (DSSF) measurement, which constitutes a part of the satellite
derived total and diffuse downward surface shortwave flux (MDSSFTD) product.
MDSSFTD is issued by the Satellite Application Facility on Land Surface Analysis (LSA SAF).
However, its direct application in this area is inhibited by potential systematic
errors in the DSSF product. Therefore, this has to be addressed before the DSSF can be used downstream.

To this end, we implemented a neural network-based post-processing procedure
that uses previous temporal DSSF observations and additional predictors, such
as cloudiness and time of day, to generate a corrected DSSF value. The ground
truth for this regression task are the in-situ measurements across a variety of
locations in Slovenia. Additionally, the neural network produces DSSF estimates
in terms of quantiles, providing an uncertainty estimate of the corrected prediction itself.

We verified our new method on the aforementioned region over a period of
four years. We found that our neural network approach successfully reduces
the presence of systematic differences present in the DSSF. Additionally, the
neural network method outperforms a baseline look-up-table approach in terms
of multiple criteria, such as mean absolute error, bias, and error variability.

How to cite: Savli, M. and Mlakar, P.: Reduction of systematic differences of LSASAF shortwave solar radiation fluxes using neural networks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9396, https://doi.org/10.5194/egusphere-egu24-9396, 2024.

EGU24-9862 | Posters on site | ERE2.1

Do offshore wind farms weaken or enhance surface wind and wave fields? 

Xiaoli Larsén, Jana Fischereit, Konrad Bärfuss, and Astrid Lampert

Over the North Sea, larger and larger part of the water surface is being covered by wind farms. Studies have shown consistent results regarding farm wake effects at hub height, characteristic of reduced wind speed and enhanced turbulence. Close to water surface, published studies using both measurements and modeling have suggested enhanced wind speeds sometimes, and reduced wind speeds some other times. Hence, this study investigates the research question: Do offshore wind farms weaken or enhance surface wind and wave fields?

We use the mesoscale atmosphere-wave-wake coupled modeling system that consists of the Weather Research and Forecast (WRF) model, Spectral Wave Nearshore (SWAN) model with the wave boundary-layer model (Du et al. 2017, Fischereit et al. 2022). We use the Fitch Wind Farm Parameterization scheme (Fitch et al. 2012), with four coefficients for the advection of the wind farm-generated Turbulence Kinetic Energy (TKE): a = 1, 0.25, 0.1 and 0, corresponding to larger and larger TKE advection. The model is used together with flight measurements of wind fields upwind, above and downwind of offshore wind farms, collected during the project WIPAFF (Bärfuss et al. 2019, Lampert et al. 2020). We use two case studies, one following Bärfuss et al. (2021) (with fetch effect) and one following Larsén and Fischereit (2021) (without fetch effect). 

There is no evidence of generally enhanced surface winds and waves in the presence of wind farms. Enhanced surface winds and waves can however be generated numerically when using e.g. a = 1, as a result of numerical distribution of excessive TKE and momentum generated at hub height down to the surface. The study suggests that the wake effect is rather sensitive to the value of a, regarding both horizontal and vertical distribution from the hub height. Measurements are needed to understand the distribution of turbine-generated TKE and to help defining a- value for specific conditions.

References:

Bärfuss, et al. 2019: In-situ airborne measurements of atmospheric and sea surface parameters related to offshore wind parks in the German Bight,  https://doi.pangaea.de/10.1594/PANGAEA.902845, 2019.

Bärfuss et al. 2021: The Impact of OffshoreWind Farms on Sea State Demonstrated by Airborne LiDAR Measurements. J. Mar. Sci. Eng.  9, 644. https://doi.org/10.3390/jmse9060644

Du J., Bolaños R. and Larsén X. 2017: The use of a wave boundary layer model in SWAN. J. Geophys. Res.:Oceans. DOI: 10.1002/2016JC012104, vol. 122, No 1, p42 - 62.

Fischereit, J., Larsén, X.G. and Hahmann A. 2022: Climate impacts of wind-wave-wake interactions in offshore wind farms. Frontier Energy Res. doi: 10.3389/fenrg.2022.881459. Vol. 10., 881459.

Fitch et al. 2012: Local and Mesoscale Impacts of Wind Farms as Parameterized in a Mesoscale NWP Model, Mon. Weather Rev., 140, 3017–3038, https://doi.org/10.1175/MWRD-11-00352.1.

Lampert et al. 2020: In-situ airborne measurements of atmospheric and sea surface parameters related to offshore wind parks in the German Bight, Earth Syst. Sci. Data, 12, 935–946.

Larsén X. and Fischereit J. 2021: A case study of wind farm effects using two wake parameterizations in the Weather Research and Forecasting (WRF) model (V3.7.1) in the presence of low-level jets. Geo. Mod. Dev., 14(5), 3141-3158. https://doi.org/10.5194/gmd-14-3141-2021

How to cite: Larsén, X., Fischereit, J., Bärfuss, K., and Lampert, A.: Do offshore wind farms weaken or enhance surface wind and wave fields?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9862, https://doi.org/10.5194/egusphere-egu24-9862, 2024.

In the quest for accurate wind resource assessment crucial for the expansion of wind farms, this study tackles the scientific question of how varying time series lengths and temporal resolutions impact the estimation of wind resources, and introduce uncertainty into the assessment process. Recognizing the significant importance of considering temporal variability in wind speed distribution, we utilize in-situ observations from weather stations provided by the Norwegian Meteorological Institute, analyzing 1-hourly data spanning one to ten years. The study employs a comparative analysis of various wind speed distributions to determine the best-fit distribution for estimating wind resources. This process involves assessing the goodness-of-fit for each distribution under different time series lengths. Additionally, the study investigates the impact of temporal resolutions by examining data collected at 10-minute, hourly, daily, and monthly intervals from the same period and stations. The overarching goal is to systematically quantify uncertainty in wind resource estimation arising from the selection of wind speed distribution based on varying lengths and resolutions of time series data. The outcomes of this research aim not only to enhance the precision of wind resource assessments in the wind power sector but also to provide valuable insights applicable to fields influenced by wind conditions, including risk management and construction design. This study is financed by the Equinor academia project.

How to cite: Zhou, L. and Esau, I.: The impact of time series length and temporal resolution on wind resource assessment: a comparative analysis of wind speed distributions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10849, https://doi.org/10.5194/egusphere-egu24-10849, 2024.

EGU24-11653 | Posters on site | ERE2.1 | Highlight

Performance of Global Wind Atlas for Distributed Wind Resource Assessment in the United States 

Lindsay Sheridan, Danielle Preziuso, Caleb Phillips, Dmitry Duplyakin, and Heidi Tinnesand

Distributed wind projects, particularly those involving small wind turbines, are more subject to financial and temporal limitations than utility-scale wind energy. Onsite measurements are often not feasible or economically viable investments, leading to developers, analysts, and customers in the distributed wind community relying on wind resource models to establish generation estimates. One popular wind product used by the distributed wind community in the United States is the global, high-resolution Global Wind Atlas from the Technical University of Denmark and the World Bank Group.

Wind resource models are valuable tools for siting and establishing generation expectations but are not entirely accurate, which can lead to distributed wind customer dissatisfaction when actual energy generation does not meet pre-construction expectations. To enhance the understanding of the performance and limitations of utilizing Global Wind Atlas for wind resource assessment, this work presents the validation of the model wind speeds using meteorological towers across the diverse geography of the United States with measurement heights relevant to distributed wind hub heights (20 m – 100 m). The analysis expands to quantify the performance of Global Wind Atlas in representation of seasonal, diurnal, and interannual variability in the wind resource along with an assessment of wind shear accuracy at locations with measurements at multiple heights.

How to cite: Sheridan, L., Preziuso, D., Phillips, C., Duplyakin, D., and Tinnesand, H.: Performance of Global Wind Atlas for Distributed Wind Resource Assessment in the United States, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11653, https://doi.org/10.5194/egusphere-egu24-11653, 2024.

EGU24-12053 | Orals | ERE2.1

Evaluation and Bias Correction of the ERA5 Reanalysis for Wind and Solar Energy Applications 

James M. Wilczak, Elena Akish, Antonietta Capotondi, and Gilbert Compo

The applicability of the ERA5 reanalysis for estimating wind and solar energy generation over the contiguous United States is evaluated using wind speed and irradiance variables from multiple observational data sets.  After converting ERA5 and observed meteorological variables into wind power and solar power, comparisons demonstrate that significant errors in the ERA5 reanalysis exist limiting its direct applicability for a wind and solar energy analysis.  Overall, ERA5-derived solar power is biased high, while ERA5-derived wind power is biased low.  Errors for the shortest duration, most extreme solar negative anomaly events are found to be statistically reasonably well represented in the ERA5, when completely overcast conditions occur in both ERA5 and observations.  Longer duration events on weekly to monthly timescales, which include partially cloudy days or a mix of cloud conditions, have ERA5-derived solar power errors as large as 40%.  ERA5-derived solar power errors are found to have consistent characteristics across the CONUS region.  The negative bias errors in the ERA5 windspeeds and wind power are largely consistent across the central and northwestern US, and offshore, while the eastern US has an overall small net bias.  For weekly to monthly timescales, the uncorrected ERA5-derived wind power errors approach 50%.  Corrections to the ERA5 are derived using a quantile-quantile method for solar power, and linear regression of wind speed for wind power.  These corrections greatly reduce the ERA5 errors, including for extreme events associated with wind and solar energy droughts, that will be most challenging for electric grid operation, while also avoiding potential over-inflation of the reanalysis variability resulting from differences between point-measurements and the temporally and spatially smoother reanalysis values.

How to cite: Wilczak, J. M., Akish, E., Capotondi, A., and Compo, G.: Evaluation and Bias Correction of the ERA5 Reanalysis for Wind and Solar Energy Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12053, https://doi.org/10.5194/egusphere-egu24-12053, 2024.

EGU24-12318 | ECS | Posters on site | ERE2.1

Estimation of Diffuse Solar Radiation Models for a Tropical Site in Nigeria 

Olanrewaju Soneye-Arogundade and Bernhard Rappenglueck

Knowledge of solar radiation and its components in a particular area is crucial in studying solar energy and constructing solar energy devices due to the many advantages solar radiation has over fossil fuels. In this two-year study, conducted at a tropical site in Ile-Ife, Nigeria, from January 2016 to December 2017, twenty-one empirical models were proposed to estimate diffuse solar radiation using continuous solar radiation data. The models were divided into five groups and developed using relative sunshine duration and/or clearness index as input variables. The performance of five models from the literature was also examined and compared to measured data. The models' performance was evaluated using the Akaike Information Criteria (AIC), the Global Performance Index (GPI), and various statistical errors. Model 11, a quadratic model with clearness index as an input variable, had the lowest AIC (1.8098), AICC (4.8099), ∆AICC (0.0000), and GPI (-2.1796) values and was the most accurate model for estimating diffuse solar radiation at the study site and other locations with similar climatic conditions. None of the models selected from the literature was suitable for estimating diffuse solar radiation at the study site; hence, the proposed models performed better.

How to cite: Soneye-Arogundade, O. and Rappenglueck, B.: Estimation of Diffuse Solar Radiation Models for a Tropical Site in Nigeria, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12318, https://doi.org/10.5194/egusphere-egu24-12318, 2024.

EGU24-15512 | Posters on site | ERE2.1

Towards efficient methods for estimating spatio-temporal wind energy yields in mountainous regions 

Nora Helbig, Florian Hammer, Reinhard Bischoff, Michael Lehning, and Sarah Barber

Complex mountain winds provide a largely unknown wind energy potential. Mountainous terrain influences air flow by e.g., wind flow sheltering, ridge acceleration, channelling, deflections, blocking and recirculation. Its impact on the energy production of wind turbines has not yet been thoroughly quantified, but various studies show that it could be significant. To accurately assess the wind energy potential in mountainous terrain, spatio-temporal wind fields capturing local wind-topography interactions are required. Ground measurements can retrieve spatio-temporal wind fields, but even with a dense weather station network, atmospheric models are still needed to capture the full spatial variability. However, it is challenging to generate the necessary fine-scale wind fields over long timescales and large regions computationally efficiently. Wind farm planning in mountainous regions is therefore much more challenging and uncertain than in flat areas.

Here, we present our concept that addresses this challenge by evaluating and enhancing various state-of-the art computationally efficient downscaling methods (statistical and dynamical). These methods generate highly resolved spatio-temporal wind fields, considering dominant local wind-topography interactions. Using these fields, we can derive time-resolved wind energy yield potential. The evaluation involves assessing the methods across fine spatial scales (e.g., dekameter scale), large spatial extents (up to tens of kilometers), high temporal resolution (e.g., hourly scale), and long timescales (several years) in real Swiss mountain settings using wind field and energy production measurements. Our overall goal is to provide wind modelers and energy planners with recommendations for efficient methods for obtaining highly resolved spatio-temporal wind fields, enabling accurate energy yield estimations in mountainous terrain.

How to cite: Helbig, N., Hammer, F., Bischoff, R., Lehning, M., and Barber, S.: Towards efficient methods for estimating spatio-temporal wind energy yields in mountainous regions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15512, https://doi.org/10.5194/egusphere-egu24-15512, 2024.

With the rapid development of wind energy, the imperative for precise wind power predictions has intensified, with the crux lying in forecasting wind speeds. The accurate short-term (1 to 3 days) forecast of wind speeds at the hub height in boundary layer poses a significant scientific challenge. Generating such forecasts for wind farms 1 to 3 days in lead time necessitates reliance on global weather forecast products and the WRF model. In pursuit of heightened accuracy, artificial intelligence (AI) algorithms are employed to refine WRF-predicted wind speeds based on observational data.

This study draws upon observational data from five operational wind farms over three years, employing diverse deep time-series models, to examine the effectiveness and limitations of these models in post-processing corrections for WRF-predicted wind speeds. Based on our examination, we conclude that: 1) Transformer-based models have significant untapped potential, with the Pyraformer model emerging as a well-suited temporal model for post-processing corrections in wind speed and power predictions. 2) Traditional full-attention mechanisms are less effective, highlighting the importance of sparse attention as a vital approach for capturing temporal correlations in such problems. 3) The optimal model demonstrates a reduction of approximately 20% in RMSE for single-point post-processing corrections. In addition, wind speed prediction accuracy reaches around 86%, and power prediction accuracy is approximately 82%. 4) AI-based post-processing corrections may encounter challenges, including the underestimation for high-value and difficulties in reproducing forecasts below the average value.

How to cite: Xia, X. and Luo, Y.: Application of WRF-Based Single-Point Data Artificial Intelligence Post-Processing Correction Method in Practical Short-Term Wind Speed and Power Forecasting, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16521, https://doi.org/10.5194/egusphere-egu24-16521, 2024.

EGU24-17204 | Orals | ERE2.1

Improving Renewable Energy Forecasting with Meteomatics EURO1k Model 

Julie Thérèse Pasquier, Johannes Rausch, Matthias Piot, Julia Schmoeckel, Marco Thaler, Christian Schluchter, and Martin Fengler

The production of renewable energy from wind and solar sources is intricately linked to meteorological conditions, where wind speed and solar radiation play critical roles. Due to the success of renewable energies, wind turbines are increasingly placed in sites with complex terrain, while solar panels are increasingly situated in alpine areas. However, current weather models often struggle to accurately forecast the weather, especially over complicated topography, due to limitations in spatial resolution. This leads to inaccurate predictions of power production, impacting the efficiency and reliability of renewable energy systems. To address this challenge, Meteomatics developed the EURO1k model, the first pan-European weather model with a 1 km² spatial resolution, providing optimal forecasting for wind and solar power.

The EURO1k model offers a 48-hour forecast horizon, generating a new forecast every hour. In addition to standard data sources such as weather stations, radar, satellite data, and radiosondes, the EURO1k model also incorporates data from a network of Meteodrones - small, unmanned aircraft systems developed by Meteomatics - which collect vertical atmospheric profiles up to 6000m in altitude. The high resolution of the EURO1k model enables accurate representation of small-scale weather patterns, resulting in highly accurate and precise forecasts.

Meteomatics uses a forecast system that combines various global and regional weather models to predict wind and solar power, aiming to reduce average errors. Recently, EURO1k has been integrated into this system, improving intraday and day-ahead power production forecasts. The normalized root mean square error (nRMSE) was reduced by up to 8.1% for intraday and by up to 8.5% for the day-ahead wind power forecast. Furthermore, a comparison of day-ahead forecasts with actual production data, combined with balancing energy costs, demonstrates improved earnings with the addition of the EURO1k model. Indeed, the EURO1k shows especially better performance in weather situations with large uncertainties. This underscores the added value of EURO1k in power forecasting, enhancing the cost efficiency of renewable energies and fostering greater integration into the energy mix, thereby reducing CO2 emissions.

How to cite: Pasquier, J. T., Rausch, J., Piot, M., Schmoeckel, J., Thaler, M., Schluchter, C., and Fengler, M.: Improving Renewable Energy Forecasting with Meteomatics EURO1k Model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17204, https://doi.org/10.5194/egusphere-egu24-17204, 2024.

EGU24-17213 | ECS | Posters on site | ERE2.1

Comparing PV and Wind Models to Analyse Dunkelflaute Events in Ireland 

Boris Morin, Damian Flynn, Conor Sweeney, and Aina Maimo Far

The 2024 Government of Ireland Climate Action Plan aims to increase the share of renewable energy sources (RES) from 38% to 80% by 2030. In 2022, the installed capacity of wind power will surpass 4.5 GW, and the goal is to reach the same level as solar power by 2025. As the proportion of energy generated from these weather-dependent sources increases, there is a need to more accurately quantify periods when the energy generated from such sources is low for an extended period, in order to plan for appropriate reserve capacity.

The terms "Dunkelflaute" and “Renewable Drought” have been used to refer to extended periods of time when the capacity factor of both wind and solar power falls below a given threshold for a set period of time. In this study, we define a Dunkelflaute event as occurring when the combined capacity factor for wind and solar falls below a fixed threshold for at least 24 hours. The effect of choosing different values for this fixed threshold is also investigated in our study.

This study aims to investigate how the expected frequency and duration of Dunkelflaute events identified in different RES datasets may change depending on the assumptions made by the underlying RES datasets.

The first RES dataset investigated is an hourly estimate of electricity generation based on ERA5 climate variables, made by C3S Energy, which was produced using statistical and physical models. The C3S Energy dataset provides a time series of electricity supply from wind and solar photovoltaic and is trained using European Network of Transmission System Operators for Electricity (ENTSO-E) data.

This dataset has certain limitations. First, it assumes a homogeneous spatial distribution of the installed capacity of wind and solar energy production, to maintain a methodological coherence between the two RES sources. Second, the energy conversion models applied, contain simplifying approximations, such as using a single wind turbine model with a fixed hub height for all locations.

The second RES dataset has been created by the authors, which uses more detailed information about the location of the wind and PV farms. Relevant atmospheric variables are interpolated from ERA5 data to the location of each RES farm. In addition, the characteristics of the wind and PV panels at each farm are taken into account.

Both datasets are compared against the actual wind and PV capacity factor data supplied by the national grid operator of Ireland, EirGrid, for the year 2023, to indicate the performance of each model. The two datasets are then analysed across the full range of the time series, from 1979 to 2023, to determine the frequency and duration of all Dunkelflaute events during this period.

Differences in the identified Dunkelflaute events highlight the importance of considering results in the context of the driving data, which would be important for future policy decisions such as planning reserve capacity requirements, or locating future RES farms.

How to cite: Morin, B., Flynn, D., Sweeney, C., and Maimo Far, A.: Comparing PV and Wind Models to Analyse Dunkelflaute Events in Ireland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17213, https://doi.org/10.5194/egusphere-egu24-17213, 2024.

EGU24-17394 | ECS | Orals | ERE2.1

How do convective cold pools influence the stability and turbulence conditions in the vicinity of wind turbines in Northern Germany? 

Jeffrey Thayer, Gerard Kilroy, Norman Wildmann, and Antonia Englberger

Convective cold pools routinely pass over the dense network of wind turbines in northern Germany, causing short-term changes in boundary-layer wind speeds (i.e., wind ramp events) and atmospheric stability. These large, rapid, and more-localized variations in the low-level kinematic and thermodynamic structure are difficult for numerical weather prediction models to forecast with sufficient spatial and temporal accuracy for utilization by wind turbine operators. As boundary-layer stability and winds strongly influence wind turbine structural loads, downstream turbulent wake behavior, and power generation, it is important to better understand how rapid changes in dynamic processes evolve within the vertical layer of wind turbine rotor blades (~50 - 150 meters altitude).

Using in-situ observations and high-resolution modeling focused on the WiValdi research wind park in Krummendeich, Germany, we examine how convective cold pool passages during July 2023 impact the inflow and turbulent wakes for two installed turbines with a hub height of 92 meters. Meteorological mast, Doppler wind lidar, and microwave radiometer observations provide upstream and downstream measurements of stability, vertical shear, and turbulence variations at ~1-minute resolution. While this measurement coverage adequately captures the cold pool evolution relative to each turbine, we remain somewhat limited by the fixed instrument locations for measuring upstream conditions and the three-dimensional turbulent wake structure. Therefore, we also utilize the mesoscale model WRF in large-eddy-simulation mode, with inserted generalized actuator disks acting as proxy wind turbines, to analyze far-upstream inflow conditions and three-dimensional wake characteristics during cold pool passages. The proposed work will provide a foundation for future analysis which will more robustly verify WRF output using additional WiValdi instrumentation.

How to cite: Thayer, J., Kilroy, G., Wildmann, N., and Englberger, A.: How do convective cold pools influence the stability and turbulence conditions in the vicinity of wind turbines in Northern Germany?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17394, https://doi.org/10.5194/egusphere-egu24-17394, 2024.

EGU24-17521 | ECS | Posters on site | ERE2.1

Fault Detection in Solar Thermal Systems using Probabilistic Reconstructions 

Florian Ebmeier, Nicole Ludwig, Jannik Thümmel, Georg Martius, and Volker H. Franz

As heating is the largest factor of Greenhouse gases in the household sector, it should
be the focus of our decarbonisation efforts. Solar Thermal Systems (STS), which provide
heat based on solar energy, are a promising technology in this regard. However, STS
are prone to faults due to improper installation, maintenance, or operation, often leading
to a substantial reduction in efficiency, damage to the system, or even an increase in
energy cost. As individual monitoring is economically prohibitive for small-scale systems,
automated monitoring and fault detection should be used to address this issue.
We propose a data-driven neural network approach for fault detection in small-scale
STS, utilising probabilistic reconstructions from a long short-term memory (LSTM) based
Variational Autoencoder (VAE). Key factors in our approach are generalising from faultless
data to previously unseen systems and an anomaly score derived from an ensemble of
reconstructions. We apply this to an operational dataset provided by our industry partner,
which includes systems with different types of faults.
Our results show that our model can detect faults in STS with comparable performance
to the state-of-the-art expert-based system used by our industry partner. Furthermore, our
model can detect previously undetected faults, specifically those resulting from unexpected
behaviour in the control software or behaviours that were entirely unexpected and not
considered in the expert-based system. Thus, a combination of our model and the expert-
based system covers a broader range of faults than either system and is proposed for
further use in the industry partner’s application. Additionally, other providers without a
functioning expert-based system could build upon our work to get a minimal viable product
for fault detection in STS, purely based on data from existing systems and without the
need to install additional sensors or domain-specific knowledge.

How to cite: Ebmeier, F., Ludwig, N., Thümmel, J., Martius, G., and Franz, V. H.: Fault Detection in Solar Thermal Systems using Probabilistic Reconstructions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17521, https://doi.org/10.5194/egusphere-egu24-17521, 2024.

EGU24-17552 | Orals | ERE2.1

Long range lidar for short term wind predictions for offshore wind parks 

Janina Bade, Hans-Jürgen Kirtzel, Leon Heinze, Piet Markmann, Gerhard Peters, Christoph Bollig, Sebastian Ulonska, Florian Jordan, and Guntram Huschenbeth

A novel lidar prototype for horizontal Doppler wind measurements with more than 30 km maximum range is presented. The request for such long-range measurements arose from the development of methods for improved prediction of potential and actual feed-in of wind power from offshore wind farms in the project WindRamp. The target is a short-term prediction horizon of up to 30 minutes.

The coherent lidar module is based on a robust fiber amplifier architecture developed within the project. This enables deployment in harsh environments in the future, e.g. at offshore wind farms. The emitted laser beam is eye save (class 1M).

In order to emulate operating conditions of an offshore platform, the system was deployed at the mouth of the Elbe river at 10 m above sea level with unobstructed view in a broad SW-sector. Scans between 204° and 304° azimuth at 0.35° Elevation were performed. The averaging time was 1 s and the angular speed 0.6° s-1.

The lidar performance is demonstrated by observations of wind fronts propagating through the observed area. The weather in North Germany during winter 2023/24 was characterized by unusual persistent precipitation, low hanging clouds and fog, which are unfavourable conditions for lidar operation. Therefore, the observed availability of valid data versus range represents a conservative estimate of the system’s potential.

How to cite: Bade, J., Kirtzel, H.-J., Heinze, L., Markmann, P., Peters, G., Bollig, C., Ulonska, S., Jordan, F., and Huschenbeth, G.: Long range lidar for short term wind predictions for offshore wind parks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17552, https://doi.org/10.5194/egusphere-egu24-17552, 2024.

EGU24-17848 | Posters virtual | ERE2.1

IEA Wind Task 51 – Minute and Seasonal Scale Forecasting Workshops for the Weather Driven Energy System 

Gregor Giebel, Caroline Draxl, Helmut Frank, John Zack, Corinna Möhrlen, George Kariniotakis, Jethro Browell, Ricardo Bessa, and David Lenaghan
The energy system needs a range of forecast types for its operation in addition to the narrow wind power forecast. Therefore, the notionally largest group world-wide discussing renewable forecasts, IEA Wind Task 51 “Forecasting for the Weather Driven Energy System” is reaching out to other IEA Technology Collaboration Programmes such as the ones for PV, hydropower, system integration, hydrogen etc. The three existing Work Packages (WPs) on NWP Improvements (WP1), Power and Uncertainty Forecasting (WP2) and optimal use of Forecasting Solutions (WP3), are complemented by thirteen work streams in a matrix structure.
 
The three work packages span three distinct areas of challenge in forecasting for the weather driven energy system. The first area is the continuing effort to improve the representation of physical processes in weather forecast models through both new high performance initializations and tailored parameterizations. The second area is the heterogeneity of the forecasters and end users, the full understanding of the uncertainties throughout the modelling chain and the incorporation of novel data into power forecasting algorithms. A third area is representation, communication, and use of these uncertainties to industry in forms that readily support decision-making in plant operations and electricity markets.

Task 51 focuses on facilitating communication and collaborations among international research groups engaged in the improvement of the accuracy and applicability of forecast models and their utility for the stakeholders in the wind industry, in the power sector and in the energy system.

The collaboration is also structured in work streams, more targeted around a particular topic and potentially spanning several work packages [1]. Two of those work streams are aligned around forecasting horizons, the one on Sub-seasonal to Seasonal (S2S) forecasting and the one on minute-scale forecasting. Both work streams had public workshops. The Seasonal Forecasting workshop was in Reading (UK) in May 2023, while the Minute Scale Forecasting workshop  was on 10/11 April 2024 in Risø (DK). While the S2S workshop was done in conjunction with WMO, the Minute Scale workshop had people from several other IEA Wind Tasks (Lidars, Wind Farm Flow Control and Hybrid Power Plants) as well as representatives of IEA PVPS Task 16 for the solar side in the committee. The poster will discuss the results of both workshops.

 

Reference: [1] https://www.iea-wind.org/task51/   The Task website, last accessed 10 January 2024

How to cite: Giebel, G., Draxl, C., Frank, H., Zack, J., Möhrlen, C., Kariniotakis, G., Browell, J., Bessa, R., and Lenaghan, D.: IEA Wind Task 51 – Minute and Seasonal Scale Forecasting Workshops for the Weather Driven Energy System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17848, https://doi.org/10.5194/egusphere-egu24-17848, 2024.

As China strides towards its carbon neutrality target by 2060, the strategic planning of renewable energy distribution and power plant installations becomes imperative to fulfill the renewable energy penetration goals. This study presents a comprehensive assessment of the future projections of solar and wind power resources in China, utilizing the latest Coupled Model Intercomparison Project Phase 6 (CMIP6) models. We examine various CMIP6 scenarios to project the geographical and temporal variations of solar and wind energy potential up to 2100. A verification assessment was carried out using terrestrial solar radiation and wind speed data sourced from 17 stations operated by the China Meteorological Administration (CMA). This evaluation revealed that the Meteorological Research Institute Earth System Model version 2-0 (MRI-ESM2-0) demonstrated overall superior performance in terms of correlation coefficients (R) and Root Mean Square Error (RMSE). Then MRI-ESM2-0 was selected to examine the spatial and temporal shifts in solar and wind potential in China. Notably, in the SSP585 scenario, a marked decrease in both PV power potential and wind power potential was observed. Additionally, the future spatial complementarity between solar and wind power in China was evaluated using the Pearson correlation coefficient and Kendall rank correlation coefficient and this was juxtaposed with the present complementarity. These maps provide a crucial reference for guiding the planning and management of renewable energy resources in China.

How to cite: Liao, Z., Xia, X., and Luo, Y.: Future Projections and Complementarity Assessment of Solar and Wind Power in China Using CMIP6 Models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18234, https://doi.org/10.5194/egusphere-egu24-18234, 2024.

EGU24-18322 | ECS | Posters on site | ERE2.1

An evaluation of wind speed profiles in model-based reanalyses using ground-based measurements of high quality in the context of wind energy generation 

David Geiger, Dehong Yuan, Thomas Spangehl, Doron Callies, Jaqueline Drücke, Garrett Good, Frank Kasper, and Lukas Pauscher

Wind speed from atmospheric reanalyses is often used as input for modelling wind energy production in energy systems analysis. While some studies compare energy generation of wind turbines to those modelled from reanalysis data sets for specific sites, such analyses are usually aggregated to regional or national levels. However, nationwide evaluations using high quality wind speed measurements at heights relevant for modern wind turbines are still scarce. 

This paper presents a detailed comparison of high quality wind speed measurements of tall profiles with different reanalysis datasets at more than 75 locations in Germany measured by lidars and masts. Among the evaluated model-based products are the regional reanalysis COSMO-REA6, the global reanalysis ERA5 and the new European reanalysis CERRA. They are evaluated at different measurement heights using statistical analysis. All sites include measurement heights above 100 m and are suited for wind energy applications. This evaluation dataset provides good coverage of the relevant terrain ranging from offshore to the low mountain regions. Measurement locations are distributed all over Germany. Data was collected over multiple years (2012 – 2023) and measurement durations at individual locations range from months to multiple years. Many of the measurements were carried out adhering to the current standards used in wind resource assessment or have comparable quality. Thus, the dataset allows for a unique and comprehensive evaluation of the reanalysis datasets with respect to the representation of geographic and topographic features as well as seasonal patterns in the context of wind energy generation. 

To address current advancements in wind power generation, our analysis focuses on heights above 100 m to reflect the height of modern wind turbines. 

First analysis results using ERA5 and COSMO-REA6 indicate a distinct effect of the terrain on the model skill. Both reanalyses have a small median bias across all measurements with larger variations seen for ERA5. There is a height dependency in the bias of the wind speed, with positive (negative) biases for lower (higher) orographic measurement heights – i.e. the terrain height at which the lidar or mast is installed. The bias varies depending on the elevation of the measurement position in hilly/mountainous terrain. A clear correlation can be observed for the bias and the difference of the terrain height at the measurement location and the orographic height of the assigned model grid box. While for elevated lidar/mast positions (higher than the model grid cell) a clear tendency towards higher measured wind speeds can be observed the effect vanishes for measurement sites close to the orographic model height. 

How to cite: Geiger, D., Yuan, D., Spangehl, T., Callies, D., Drücke, J., Good, G., Kasper, F., and Pauscher, L.: An evaluation of wind speed profiles in model-based reanalyses using ground-based measurements of high quality in the context of wind energy generation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18322, https://doi.org/10.5194/egusphere-egu24-18322, 2024.

EGU24-18854 | ECS | Orals | ERE2.1

Solar Radiation Forecasts from Large Eddy Simulations and Observations using Ensemble Kalman Filtering 

Marleen van Soest, Harm Jonker, and Stephan de Roode

The increase in renewable energy production demands forecasting of wind and solar radiation due to their greater variability compared to non-renewable energy sources. The variability in solar energy is primarily caused by clouds. Large Eddy Simulation (LES) proves effective for high-resolution solar radiation prediction, capturing clouds like stratocumulus where large-scale models cannot. LES uncertainty in clouds primarily stems from initial conditions taken from these large-scale models. In this study, an ensemble Kalman filter assimilates observations into LES initial conditions. A large ensemble is created from a limited amount of LES runs by taking advantage of their internal variability. From this ensemble and measurements from the Cabauw measurement site, improved initial conditions are calculated for a range of stratocumulus cases. These cases are simulated without further interference. The method shows a 60% reduction in Root Mean Square Error (RMSE) for shortwave down solar radiation at the initial condition over the unfiltered initial condition. This improvement persists at 45% after 3 hours of simulation, showing the lasting impact of assimilated observational data on predictive accuracy. The decrease can be accounted to a combination of microphysical processes, energy fluxes from the lower boundary condition and the advective tendencies in the model. In future work, possible improvements to these processes will be identified and the method will be evaluated for other sites and cloud conditions.

How to cite: van Soest, M., Jonker, H., and de Roode, S.: Solar Radiation Forecasts from Large Eddy Simulations and Observations using Ensemble Kalman Filtering, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18854, https://doi.org/10.5194/egusphere-egu24-18854, 2024.

The growing importance of the offshore wind energy sector emphasizes the need for projections of the long-term energy yield for existing and planned wind farm installations. In the North Sea, where wind farms are already pivotal to the electricity mix of the surrounding countries, the production capacity is set to increase tenfold by 2050. Studies suggest that, by 2050, the wind climate over the North Sea basin may differ significantly from the historical climate (Carvalho et al., 2021; Hahmann et al., 2022). Here, we combine an analysis of CMIP6 projections with an ERA5-driven, mesoscale wind farm simulation to further explore the impact of near-future wind climate changes over the North Sea on the energy production. First, an ensemble of 17 GCMs is reduced to 12 GCMs based on an analysis of the ability to represent the historical wind rose at 100 m MSL (1985-2014). Next, we identify future decades for each season where the wind rose exceeds the range of the historical decadal variability. Based on these extreme wind roses, we then apply a sub-sampling to a 30-year, ERA5-driven COSMO-CLM simulation covering the North Sea and incorporating a projected, 250 GW wind farm layout. Based on the sub-sampled datasets, we then quantify the impact of these extreme 10-year wind roses on the energy production of different wind farm clusters and compare this against an historical baseline.

How to cite: Borgers, R., Pinto, J., Meyers, J., and van Lipzig, N.: Future wind energy production over the North Sea for extreme, 10-year wind roses based on CMIP6-informed subsampling of an ERA5-driven RCM simulation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20273, https://doi.org/10.5194/egusphere-egu24-20273, 2024.

EGU24-20569 | Posters on site | ERE2.1

Investigation of air-sea interaction with a One-Way Coupling: MIKE 3 wave and WRF-LES 

Sima Hamzeloo, Xiaoli Guo Larsén, Alfredo Peña, and Jacob Tornfeldt Soerensen

The study aims to couple the Weather Research and Forecasting (WRF) [1] model of the large eddy simulation (LES) module with the MIKE 21 wave [2] model to study the effect of surface waves on the atmospheric flow over the North Sea. We provide a realistic surface wave field with MIKE 21 by forcing Era5 wind speed. We examine the effect of such wave fields on the atmosphere for a variety of met-ocean conditions, from normal to extreme conditions. The methodology involves applying simulated significant wave heights as the surface boundary for the WRF model, employing the LES module to capture the three-dimensional as well as smaller scales of turbulence that are unresolved by WRF-LES. The simulations will be validated using atmospheric and wave measurements in the North Sea, e.g., from the FINO 1 and 3 metocean research platforms. The preliminary results include the model outputs, including the spatial distribution of wind fields under different wave conditions.

[1] Skamarock, W. C., Klemp, J. B., Dudhia, J., Gill, D. O., Liu, Z., Berner, J., … Huang, X. -yu. (2019). A Description of the Advanced Research WRF Model Version 4.1 (No. NCAR/TN-556+STR).

[2] https://www.mikepoweredbydhi.com/

How to cite: Hamzeloo, S., Guo Larsén, X., Peña, A., and Soerensen, J. T.: Investigation of air-sea interaction with a One-Way Coupling: MIKE 3 wave and WRF-LES, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20569, https://doi.org/10.5194/egusphere-egu24-20569, 2024.

EGU24-22047 | Orals | ERE2.1

Effect of Saharan dust storm events on the forecast of photovoltaic power generation in Hungary 

György Varga, Fruzsina Gresina, József Szeberényi, András Gelencsér, and Ágnes Rostási

The expansion of renewable energy sources is a major issue from the sustainability, climate policy and energy security perspectives. All of this expansion can be optimal if its potential is exploited to the best possible effect, and accurate forecasting of irradiance levels, both for existing and planned capacity, is essential.

Solar forecasting is the process of predicting the expected solar output from a photovoltaic (PV) system over a given period. This process is important for power system operators and utility companies who need to ensure that they can meet the electricity demand of their customers by balancing the supply and demand of energy on the grid.

Our research investigated the impact of mineral dust on photovoltaic power generation and day-ahead forecast. We analysed the year 2022, when the number of Saharan dust storm events identified in Hungary (n=16) set a new record. Our methods included satellite measurements, numerical simulations, air mass movement trajectory calculations and synoptic meteorological analyses, as well as laboratory analyses of the dust material that washed out with precipitation during Saharan dust storm events. During some episodes, a deficit of up to 500 MW between actual and predicted output was periodically detected, which required the use of expensive and polluting back-up capacity.

We have shown that the semi-direct effect of atmospheric dust particles on high-level cloud formation rather than their direct irradiance-reducing effect is responsible for the reduced accuracies of e short-term (24-h) PV energy production forecasts during these events.

The results were published in Varga et al. (2024). Effect of Saharan dust episodes on the accuracy of photovoltaic energy production forecast in Hungary (Central Europe). Renewable and Sustainable Energy Reviews 193, https://doi.org/10.1016/j.rser.2024.114289

The research was supported by the NRDI projects FK138692 and RRF-2.3.1-21-2021. The research was funded by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences (FFT NP FTA).

 

How to cite: Varga, G., Gresina, F., Szeberényi, J., Gelencsér, A., and Rostási, Á.: Effect of Saharan dust storm events on the forecast of photovoltaic power generation in Hungary, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22047, https://doi.org/10.5194/egusphere-egu24-22047, 2024.

EGU24-1227 | ECS | Orals | ERE2.3

Increases in extreme power shortage events of wind-solar supply systems worldwide 

Dongsheng Zheng, Dan Tong, Steven J. Davis, Yue Qin, Yang Liu, Rongchong Xu, Jin Yang, Xizhe Yan, and Qiang Zhang

Extreme power shortage events, especially occurred in wind-solar hybrid supply systems, are longstanding serious threats to safeguard energy security and socioeconomic stabilization. Here, 43 years of hourly reanalysis climatological data are leveraged to examine historical trends in defined extreme long-duration and low-reliability events in wind-solar systems worldwide. We find interannual and decadal uptrends in the two types of defined extreme power shortage events regardless of their frequency, duration, and intensity since 1980. For instance, duration of extreme low-reliability events worldwide has increased by 5.39 hours (0.113 hours y−1 on average) between 1980–2000 and 2001–2022. However, such ascending trends are unevenly distributed worldwide, with a higher variability in low- and middle-latitude developing countries but a smaller change in high-latitude developed countries. This observed uptrends in extreme power shortage events are primarily driven by increases in extremely low wind speeds instead of solar radiation. However, the changes in power shortage events and extremely low wind speeds are strongly disproportionated. Only 8.80% change in extremely low wind speed gives rise to over 30% variability in extreme power shortage events, despite a mere 1.26% change in average wind speed. Our findings underline that wind-solar hybrid supply systems will probably suffer from weakened power security if such upwards trends persist in a warmer coming future.

How to cite: Zheng, D., Tong, D., Davis, S. J., Qin, Y., Liu, Y., Xu, R., Yang, J., Yan, X., and Zhang, Q.: Increases in extreme power shortage events of wind-solar supply systems worldwide, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1227, https://doi.org/10.5194/egusphere-egu24-1227, 2024.

EGU24-1409 | ECS | Posters on site | ERE2.3

Coupling economic & ecological models - the effect on biodiversity from energy grass production  

Josefin Winberg, Yann Clough, Cecilia Larsson, Johan Ekroos, and Henrik Smith

Bioenergy is expected to play a key role in the transition from fossil fuels to renewable energy sources, with biomass from grass and forestry pointed out as some of the main bioenergy sources in Northern Europe. The increased demand for biomass creates incentives for regional biofuel markets, assumed to replace imported biofuels in the substitution of fossil fuels in industries and the transport sector. In our study, we use coupled modelling of economic and ecological systems to investigate the potential landscape-scale impacts on biodiversity from increased production of lignocellulosic biomass for energy purposes in a farm-forest mosaic region in Southern Sweden. As a first step, we use the empirical and spatially explicit agent-based model AgriPoliS (Happe et al., 2006) to predict how profit-maximizing farmers respond to increased demand and price of ley biomass for energy purposes by changed farm structures and land use within a region, in response to. We expect that increased use of ley and grass biomass for energy could have a negative effect on fodder production, which in turn negatively affects dairy and livestock farming, ultimately with negative impacts on biodiversity if semi-natural grasslands (SNG) are abandoned or afforested. The impact on biodiversity from the resulting land-use changes is modelled in a second step, using a countryside species-area relationship model (cSAR) based on existing field data. By coupling the two models, we can predict the ecological impacts of changes in energy policies or markets, to ultimately understand if there are any tipping points for how much grass biomass can be used for energy until we have a decline in SNG and their associated biodiversity.

How to cite: Winberg, J., Clough, Y., Larsson, C., Ekroos, J., and Smith, H.: Coupling economic & ecological models - the effect on biodiversity from energy grass production , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1409, https://doi.org/10.5194/egusphere-egu24-1409, 2024.

EGU24-1511 | ECS | Orals | ERE2.3

Türkiye's Renewable Energy Outlook: GCM-Based Analysis and Future Projections Using the Extreme Gradient Boosting Algorithm 

Denizhan Guven, Omer Lutfi Sen, and Mehmet Ozgur Kayalica

The focus on global warming and climate change has prompted a substantial shift towards green energy technologies, which are crucial in shaping electricity generation capacity. Türkiye has actively been investing in renewable energy sources, such as wind, solar and geothermal, to reduce its dependency on imported fossil fuels and improve its energy security. In this study, we aimed to investigate the future of the electricity production in Türkiye under a changing climate using climate model projections and a machine learning algorithm. Thus, we first identified the most suitable Global Climate Models (GCMs) in simulating Türkiye's climate conditions, and then we evaluated how climate change, considering changing wind speeds, solar radiation, and temperature, will impact future electricity production in renewable energy output. We acquired historical data from 13 CMIP6 Global Climate Models, focusing on temperature, wind speed, and solar radiation parameters. Model resolution was standardized, and daily data for 120 grids in Türkiye were collected for 2010-2014. The performance of GCMs was assessed against ERA5/CRU-biased corrected datasets using metrics such as Kling-Gupta efficiency (KGE), modified index of agreement (md), and normalized root mean square error (nRMSE). A Multiple-criteria Decision Analysis (MCDA) method ranked the models based on performance, and Comprehensive rating metrics (MR) provided a unified score. Based on the result of MR, the top-performing models (ACCESS-CM2, INM-CM5–0, INM-CM4–8, and ACCESS-ESM-1-5) were ensembled, and then utilized to predict Türkiye's future climate using the Extreme Gradient Boosting Tree (XGBoost) algorithm. Projections were made for 2020-2064 under the SSP5-8.5 scenario. According to the results of the XGBoost forecast, solar power plant output is predicted to decrease across the country due to rising temperatures, with the largest drops in the Mediterranean (7.7-5.2%) and Eastern Black Sea (7.7-6.0%) regions. The Eastern Black Sea region, with low current solar potential, is deemed unsuitable for photovoltaic solar power plants in the future. Minimal decreases are anticipated in the Marmara (2.8-2.0%) and Southeastern Anatolia (2.8-4.4%) regions. Wind turbine electricity production is expected to increase, notably in Thrace (3.5-8.5%), northern Central Anatolia (3.5-8.5%), southern Southeastern Region (3.5-11.1%), and around Ağrı and Van provinces in Eastern Anatolia (3.5-6.0%). Conversely, the Eastern Black Sea, Uşak-Kütahya-Eskişehir-Bolu provinces in northwestern Anatolia (3.0-1.0%), and Mardin-Batman-Şırnak provinces in southeastern Anatolia (5.8-1.0%) may experience a decline in wind production potential. Overall, the study's findings align with existing literature, providing valuable insights into Turkey's future electricity production landscape under the influence of climate change and the transition to green energy technologies.

How to cite: Guven, D., Sen, O. L., and Kayalica, M. O.: Türkiye's Renewable Energy Outlook: GCM-Based Analysis and Future Projections Using the Extreme Gradient Boosting Algorithm, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1511, https://doi.org/10.5194/egusphere-egu24-1511, 2024.

EGU24-1723 | Posters on site | ERE2.3

Analysis of the optimal allocation of wind and solar PV capacities in a decarbonized power system in Spain using PyPSA 

Francisco Santos-Alamillos, David Pozo-Vázquez, Guadalupe Sánchez-Hernández, Antonio Jiménez-Garrote, Miguel López-Cuesta, Santiago DeFelipe-García, José Antonio Ruiz-Arias, and Joaquín Tovar-Pescador

The Spanish energy roadmap aims at producing around 80% of electricity from renewable energy by 2030, while reducing nuclear energy in a scenario of increasing demand. To this end, the target for installed capacity is 50 GW for wind energy (30 GW in 2022), 39 GW for solar PV (20 GW in 2022) and 2.5 GW for battery storage. Plans underway suggest even more ambitious goals.
We present the results of an analysis of the optimal spatial distribution of new wind and solar capacities in Spain. The study is carried out using the electrical system model PyPSA-Eur, which allows analyzing the optimal allocation and sizing of new renewable plants, taking into account the variability of generation and demand, energy costs, integration and the transmission issues. Two main scenarios are explored: 1) capital costs and 2) operational nuclear power amount (0/3/7 GW). The study assumes a 20% increase of demand by 2030 and a maximum total installed power of 160 GW. The generation and distribution networks used in PyPSA-Eur includes 9 nodes, homogeneously distributed in the study region. The model is fed with the Spanish High Resolution Renewable Energy and Demand (SHIRENDA) open access database for energy system analyses. Both combined the generation and distribution networks  and SHIRENDA allow adequately accounting for the very high spatial variability of the renewable resources in Spain. 
The results show that the new capacities should be installed in up to four of the nine regions (nodes) considered, although this strongly depends on the amount of nuclear energy. In particular, for scenarios with low nuclear power (0/3 GW) wind capacities should be installed mainly in the Galicia (northwest of the study area) and Aragón (northeast) regions, and solar PV in the regions of Murcia (southeast) and Aragón. For scenarios with fully operational nuclear energy (7 GW), the region of Andalusia (south) was also selected both for wind and solar PV. The intermediate nuclear power amount scenario (3 GW) is best from the costs standpoint. The curtailment is high (about 10%),  higher for wind, but reduces by 50% when nuclear energy is removed.
Overall, the results show that a homogeneous spatial distribution of new solar and wind capacities in the study region is far from optimal and that a better representation of the spatio-temporal variability of the renewable energy resources, as done in this study, is needed. Future work will explore the optimal ratio between solar PV and wind capacity, as well as the role of energy storage and demand management.

How to cite: Santos-Alamillos, F., Pozo-Vázquez, D., Sánchez-Hernández, G., Jiménez-Garrote, A., López-Cuesta, M., DeFelipe-García, S., Ruiz-Arias, J. A., and Tovar-Pescador, J.: Analysis of the optimal allocation of wind and solar PV capacities in a decarbonized power system in Spain using PyPSA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1723, https://doi.org/10.5194/egusphere-egu24-1723, 2024.

EGU24-2792 | ECS | Orals | ERE2.3 | Highlight

Minimizing visual impacts of renewable energy technologies and its implications for potential, costs, and energy transformation pathways: A nationwide study on Germany 

Tsamara Tsani, Jann Michael Weinand, Tristan Pelser, Maximilian Hoffmann, Romanos Ioannidis, Rachel Maier, Stanley Risch, Felix Kullmann, Russell McKenna, and Detlef Stolten

The energy transition necessitates the massive deployment of large-scale wind turbines and solar photovoltaics (PV). However, numerous countries, including Germany, have experienced setbacks in the form of project cancellations and delays that impede the installation of these technologies, which are driven by various non-technical factors. Local opposition, prompted by concerns over the visual impact of renewable energy technologies on the surrounding landscape, is one of these. Past studies have sought to tackle this problem by incorporating the visibility of wind turbines into planning considerations and potential analyses. However, these analyses have been limited to small regions and do not account for the visibility of other renewable technologies, such as solar PV.

This study employs a nationwide, integrated, reverse-viewshed analysis, potential analysis, and techno-economic analysis. Furthermore, we evaluate the effects of designing renewable energy systems that are not visible in scenic or densely-populated areas on the remaining energy potential, energy system costs, and technological choices necessary to achieving net zero emissions by 2045. Installations visible from areas with different scenicness ratings (1–9) and population density thresholds are used to define scenarios to account for the sensitivity of visual impacts on different degrees of landscape scenicness and viewed by different population segments.

Our research reveals that wind turbines with the highest levelized cost of electricity (LCOE) in Germany coincide with those that are visible from the most scenic landscapes (scenicness level 9). Therefore, minimizing the visual impact of wind turbines by placing them out of sight from the most scenic landscape areas could align with cost-effectiveness objectives. However, if the visibility restrictions become too strict (e.g., that they not be visible from scenicness levels ≥ 5 or population densities ≥ 300 people/km2), there will not be enough wind power potential (e.g., the remaining 6.8 TWh/year or 2.4 TWh/year) to cost-effectively achieve German climate targets. Instead, PV systems, with a lower visual impact, would be more favorable and selected in the optimization to meet energy demands.

How to cite: Tsani, T., Weinand, J. M., Pelser, T., Hoffmann, M., Ioannidis, R., Maier, R., Risch, S., Kullmann, F., McKenna, R., and Stolten, D.: Minimizing visual impacts of renewable energy technologies and its implications for potential, costs, and energy transformation pathways: A nationwide study on Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2792, https://doi.org/10.5194/egusphere-egu24-2792, 2024.

EGU24-3162 | ECS | Posters on site | ERE2.3

Designing integrated and resilient multi-energy systems via multi-objective optimization and scenario analysis 

Marco Tangi and Alessandro Amaranto

Multi-energy systems (MESs), which integrate various technologies and energy vectors in a single unified framework, have proven to be effective and flexible tools for addressing the challenges faced by energy systems in a changing world. These include the need for decarbonization, increasing penetration of renewable energy sources, a push for decentralization and independence in energy markets, and rapidly shifting socio-economic and climatic conditions.

However, traditional modeling tools for MESs planning and management have several shortcomings. Existing multi-energy planning and modeling frameworks often prioritize minimizing a single monetary objective. Even when multiple objectives are considered, they are often monetized, reducing the problem to a single-objective approach and limiting the exploration of possible solutions. Additionally, MES planning struggles to account for uncertainties arising from climate and socio-economic variables, especially with the rise of non-programmable energy sources and frequent disruptions in global supply chains and energy stability.

The work hereby presented aims to overcome these limitations by developing modeling frameworks that allow for exploring various configurations of multi-energy systems based on non-comparable objectives. The goal is to extract trade-off solutions through optimization algorithms under different future scenarios. The framework integrates the single-objective configuration model CALLIOPE with multi-objective evolutionary algorithms to explore the decision space thoroughly. Multiple algorithms are tested, and the best-performing algorithm is used to extract optimal configurations under alternating scenarios of renewable energy generation potential and energy prices.

The new framework is tested on a synthetic case study based on the Sulcis Iglesiente (SI) Province in Sardinia, Italy, a region facing socio-economic challenges exacerbated by the planned phase-out of a local coal power plant. The analysis considers opportunities for investing in renewable resources, expanding the local renewable power pool, installing energy storage batteries, and transitioning from gas and oil boilers to heat pumps and biomass generators. Objectives such as air quality, energy independence, economic considerations, and emission targets are taken into account.

Results demonstrate that the new methodology allows for the extraction of multiple optimal configurations of the multi-energy system, incorporating different technology combinations based on the relative importance of objectives. Among the tested algorithms, EpsMOEA and OMOPSO perform the best, thoroughly exploring the decision space and returning unique optimal configurations. Scenario analysis reveals that the attractiveness of certain technologies, especially for heat generation, is highly sensitive to different objectives and scenarios. In contrast, others, such as onshore wind plants, remain favorable regardless of circumstances.

The methodologies presented in this work signify a significant step forward in finding optimal planning and management solutions for multi-energy systems. They successfully capture the intrinsic complexity of the problems considered, supporting the search for integrated, efficient, participatory, and sustainable solutions.

How to cite: Tangi, M. and Amaranto, A.: Designing integrated and resilient multi-energy systems via multi-objective optimization and scenario analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3162, https://doi.org/10.5194/egusphere-egu24-3162, 2024.

EGU24-3822 | ECS | Posters on site | ERE2.3

The benefits of distributed grid production: An insight on the role of spatial scale on solar PV energy 

Dimitrios Chatzopoulos, Athanasios Zisos, Nikos Mamassis, and Andreas Efstratiadis

The hydrometeorological processes associated with renewables are characterized by substantial spatiotemporal variability, and thus uncertainty, which is addressed through decentralized planning, thus taking advantage of scaling effects. The objective of this work is to provide a comprehensive investigation of the role of scale regarding solar photovoltaic production in Greece, which is one of the predominant renewables. By implementing macroscopic criteria in terms of solar potential (e.g., topography-adjusted radiation indices), we select a sufficient sample of well-distributed locations in Greece. For these points, hourly radiation and temperature data, derived from satellite products, are retrieved and validated against ground observations. Following this, we formulate a detailed simulation procedure that accounts for the two physical drivers and the panel characteristics (i.e., efficiency and temperature impacts due to heating), and we configure the baseline scenario by computing the individual production of each site. Next, to highlight the added value of distributed production and quantify the scaling effects in PV power production, we follow a Monte Carlo approach by randomly distributing PVs across the selected locations, to eventually provide a statistical analysis on the spatial and temporal domain and over different PV technologies.

How to cite: Chatzopoulos, D., Zisos, A., Mamassis, N., and Efstratiadis, A.: The benefits of distributed grid production: An insight on the role of spatial scale on solar PV energy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3822, https://doi.org/10.5194/egusphere-egu24-3822, 2024.

EGU24-3907 | Orals | ERE2.3

Extreme surface solar radiation events and implications for PV energy generation 

Doris Folini, Guillaume Senger, Boriana Chtirkova, Jan Wohland, and Martin Wild

In the context of climate science and climate change, extreme events take a prominent place because of their potentially devastating impacts on various aspects of society, from economic losses to premature deaths. Much effort has gone, in particular, into the study of heat waves and droughts. Extreme events in surface solar downwelling radiation (SSR) have, by contrast, gained little interest so far. This neglect is at odds with the prominent role that photo-voltaic (PV) energy production, which feeds on SSR, is to play in the future.

Based on daily-mean data from nine global climate models participating in the pre-industrial control experiment (piControl) of the Coupled Model Intercomparison Project-Phase 6 (CMIP6), we provide a descriptive analysis of extreme events in surface solar radiation (SSR) arising from internal variability of the climate system, with a geographical focus on central Europe, where we also anchor our analysis in 38 years of observed daily mean SSR data. Two kinds of extreme events are investigated: sustained radiation events (SREs, periods of L consecutive days with extremely high or low SSR on each single day) and cumulative radiation events (CREs, yearly minimum mean SSR over a period of L days). To explore the role of extreme SSR events in PV energy generation, we use the Global Solar Energy Estimator (GSEE, https://github.com/renewables-ninja/gsee).

Selected findings from our analysis include the following. In central Europe, the frequency of SREs shows an exponential dependence on L, their duration in days. High SREs are more frequent than low SREs over global land. CREs in central Europe are well described by Generalized Extreme Value statistics with a negative shape parameter, similar to wind and temperature extremes. PV production associated with low SREs in central Europe is roughly linear in SSR with little sensitivity to panel orientation, while for high SREs PV production depends non-linearly on SSR and sensitivity to panel orientation is pronounced. PV production of high SRE events in winter greatly exceeds PV production of low SRE events in summer. Our results are a first step in examining the characteristics and relevance of SSR extreme events, highlighting the need for further studies.

How to cite: Folini, D., Senger, G., Chtirkova, B., Wohland, J., and Wild, M.: Extreme surface solar radiation events and implications for PV energy generation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3907, https://doi.org/10.5194/egusphere-egu24-3907, 2024.

Ocean thermal energy conversion (OTEC) is a form of renewable energy that could potentially displace a significant amount of fossil-fuel generated electricity. Many multi-century simulations of the UVic Earth Systems Climate Model (UVic ESCM) are presented to better understand the climate change mitigation potential and the projected magnitude and significance of the impacts of widespread OTEC implementation at varying total power outputs (3, 5, 7, 10, and 15 TW). This study builds on previous research with the inclusion of a fully coupled atmospheric model, sea ice model, and comprehensive carbon cycle model. In high emission scenarios (Representative Concentration Pathway 8.5), OTEC was found to be able to briefly produce over 36 TW of power and power production rates of 6 TW and below were found to be sustainable on multi-millennial timescales. The study also included an emission reduction associated with OTEC that resulted in cumulative emission reductions of 1190-3600 Pg C by 2500 relative to a control scenario without OTEC deployment. Environmental impacts include globally averaged sea surface temperature decreases of 0.8-3ºC relative to control values, increased heat uptake at intermediate depths, and enhanced biological production. The implementation of OTEC was found to induce overturning cells in the North Pacific and cause significant relative increases in strength of the maximum Meridional Overturning Circulation globally with values ranging from 1.6 to 8.2 Sv by 2500, depending on the level of OTEC power generation. While caution is required and the engineering challenges would be large, early indications suggest that the large-scale implementation of OTEC could make a substantial contribution to climate change mitigation.

How to cite: Nickoloff, A., Olim, S., Eby, M., and Weaver, A.: Potential Climate Change Mitigation and Environmental Impacts from the Widespread Implementation of Ocean Thermal Energy Conversion , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4156, https://doi.org/10.5194/egusphere-egu24-4156, 2024.

Rooftop solar photovoltaics (RSPV) play a pivotal role in enabling countries and cities to transit to renewable energy and achieve net-zero emissions. Effective RSPV deployment hinges on understanding its spatiotemporal patterns and a city’s capacity to integrate it, considering the challenges of supply-demand inconsistency and grid security. Despite its importance, there is a lack of high-resolution data on RSPV in terms of both power generation and accommodation potential.

 

From the perspective of RSPV technical potential, its assessment has much larger complexity than utility-scale PV systems, as individual rooftop rather than a large site serves as the smallest unit for the assessment. Given the difficulty in mapping rooftop and its available space for RSPV installation, high resolution mapping of RSPV technical potential of an entire large country remains challenging. Current literatures on this topic reach a spatial resolution on 10-100 km2 scale, which is still hard to demonstrate details within cities, and fail to account rooftop availability for each individual pixel. From the perspective of RSPV deployment potential, current literatures tend to aggregate total RSPV supply with grid demand. As different types of buildings have different load intensity and patterns, such simplification would underestimate the variability of load-accommodation ability for RSPV.

 

To tackle these challenges, we develop an integrated framework that combines high-resolution RSPV potential assessment with consumption optimization based on building-related loads. For the technical potential evaluation, we employ a machine learning model, which integrates ~30 variables from different remote sensing images and spatial explanatory data, to quantify building rooftop area and height distribution on 1 km2 scale. A rooftop availability analysis is then applied for each 1 km2 pixel based on its building density, height and property. The RSPV capacity and hourly electricity potential are then calculated through combining available rooftop and radiation modelling. For the consumption analysis model, we first use building simulation to model the hourly power demand for different buildings (urban residential, public, industry and rural) in different cities. Combining hourly RSPV potential and building-related loads, we then optimize the RSPV deployment by profit maximization, with the constraint of a series grid-accommodation scenarios. Specifically, the grid-accommodation scenarios include minimum self-consumption and maximum peak-valley difference.

 

We apply our framework to China as a case, with a potential mapping for 3,596,668 1*1km2 pixels and deployment analysis for 369 prefecture-city for each kind of buildings. The results show that the total RSPV potential in mainland China amounts to 2785 GW, with 4631 TWh annual electricity potential. Urban residential, public, industry and rural buildings respectively takes up 7.6%,7.0%,24.9% and 60.5% for total potential. We quantify the deployable RSPV capacity under various local consumption and peak-valley difference constraints, ranking different building types in different cities based on levelized cost of energy (LCOE), value of solar (VOS), and emission reduction potential. The study concludes by discussing pathways to achieve renewable energy targets based on these findings.

How to cite: Shi, M. and Lu, X.: High spatiotemporal resolution mapping of rooftop solar technical and deployment potential in China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5238, https://doi.org/10.5194/egusphere-egu24-5238, 2024.

EGU24-6895 | ECS | Posters on site | ERE2.3

Impact of Sub-Hourly Resolution on the Design and Reliability of Residential Energy System Models 

Olalekan Omoyele, Silvana Matrone, Maximilian Hoffmann, Emanuele Ogliari, Jann Michael Weinand, Sonia Leva, and Detlef Stolten

Energy system optimization has become an indispensable tool for planning the energy transition. However, model accuracy has traditionally been limited to hourly resolution due to data availability and computational complexity. This study quantifies resolution-induced inaccuracies in hourly and sub-hourly energy system optimization models. It focuses on a self-sufficient residential building by converting minutely-resolved renewable supply and demand data from Milan, Italy into data at five-, ten-, 15-, 30-, and 60-minute intervals using both averaging and sampling methods.

The average hourly resolution shows an underestimation of 1.71% in the total annualized cost of the system compared to the minutely resolution. In the electrical sub-system, the photovoltaic inverter is predominantly affected, being twice as large at minutely resolution in order to handle supply and demand peaks on the sub-hourly scale. To test for reliability, the operational performance of the optimal system layouts obtained from different resolutions is tested with minutely-resolved data. Our results show that system designs obtained for lower resolutions are infeasible for minutely data with lost loads of up to 89.37 kWh per year or 1.37% of annual electricity demand. Depending on the value of the lost load cited in the literature, this accounts for up to €893.67 of yearly inconvenience costs. A second method based on regular sampling (i.e., taking every 60th value of the original time series) shows either an under- or overestimation of the total costs depending on the selected sample (there are 60 in total), with a tendency towards conservative design layouts. The two methods (sampling and averaging) reveal that hourly resolution could be sufficient with respect to total system cost approximations, but is unacceptable for sizing dynamically-operated components and strict reliability requirements.

Future research should seek to provide higher-resolved data on intermittent renewable energy sources and appropriately handle the resulting increased computational complexity of energy system models.

How to cite: Omoyele, O., Matrone, S., Hoffmann, M., Ogliari, E., Weinand, J. M., Leva, S., and Stolten, D.: Impact of Sub-Hourly Resolution on the Design and Reliability of Residential Energy System Models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6895, https://doi.org/10.5194/egusphere-egu24-6895, 2024.

EGU24-9038 | ECS | Orals | ERE2.3

Impact of flexibility costs on electricity systems depending on regional wind and PV capacities with an application to France. 

Samouro Dansokho, Alexis Tantet, Philippe Drobinski, and Anna Creti

The adequacy of electricity systems is strongly linked to the level of Variable Renewable Energies (VREs) penetration. To ensure supply-demand balance and in the absence of other sources of flexibility, Dispatchable Units (DUs) must be operated in a more flexible manner due to the variability of REs. We expect the DUs schedule to be strongly affected by the flexibility needed from base DUs in response to increasing VREs and taking flexibility into account may lead to using some peak DUs that would be unused in a standard merit order dispatch.

We develop and apply to France a methodology to assess the system cost response to the flexibility costs change due to VREs integration at the regional scale and the impact of the latter on DUs depending on their merit order position. 

Changes in the system cost due to flexibility are diagnosed from a residual demand for regional VRE mixes at different penetration levels optimized by the e4clim model. e4clim is a minimal optimal VRE investment model based on the minimization of a system cost assuming that dispatchable costs are a function of the aggregated dispatchable production only. Considering that the standard merit order holds and for prescribed marginal costs of production, the DUs are ranked by loadpoint and defined by their marginal and rental costs. Moreover, at time scales greater than 1 hour, there are few hard flexibility constraints. It is therefore assumed that flexibility can be modeled as costs, for instance because of the extra fatigue and human resources induced by more flexible operation of DUs. Among the different forms of flexibility, we focus on ramps and start-ups. Each producer is assigned a marginal ramp (resp.~ start-up) cost proportional to its fixed cost by a coefficient KR (resp.~KSU) determined using real data.

The variable costs of flexibility are obtained by multiplying these marginal costs by the ramps and start-ups diagnosed from e4clim.

For the reference value of KSU and 50% penetration of VREs, we find that the variable cost of start-ups contributes to 7% of the system cost and that is 3.6 times larger than the ramps contribution. Secondly, the base DUs have flexibility costs higher than the maximum flexibility cost without VRE. The middle producers see theirs decrease and they completely cancel out for the last producers since they are no longer used. Finally, for large VRE penetration (≥20%), we find that PV induces twice the flexibility need induced by wind and mostly affects base DUs while wind impacts all DUs more homogeneously. 

Although flexibility costs are lower than production costs, considering them in the optimization of DUs could reduce the system cost and result in a dispatch different from the standard merit order. Furthermore, flexibility costs could be significantly reduced by considering them in the optimization of the technological and geographical distribution of VREs. Finally, the sensitivity of our results to the estimates of the coefficients KSU and KR calls for more empirical studies of the marginal costs of flexibility. 

How to cite: Dansokho, S., Tantet, A., Drobinski, P., and Creti, A.: Impact of flexibility costs on electricity systems depending on regional wind and PV capacities with an application to France., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9038, https://doi.org/10.5194/egusphere-egu24-9038, 2024.

Weather-driven periods of low electricity production from renewable energy sources (RES) can result in so-called ‘energy droughts’, sometimes known by the German term ‘Dunkelflaute’. When these weather phenomena occur over a large geographical area for extended periods of time, and coincide with periods of high electricity demand due to cold temperatures (‘kalte Dunkelflaute’), these events pose a risk for maintaining resource adequacy in a future power system relying significantly on RES.

The most robust way of identifying energy droughts is to use hourly electricity market simulations to capture both the demand- and supply-side effects of different climate years, but these simulations are computationally intensive to perform and Transmission System Operators (TSOs) can typically only consider 30-40 historical climate years in resource adequacy studies. However, as vastly more climate data is becoming available from future climate projections, a robust way to identify ‘kalte Dunkelflauten’ from climate data alone is needed in order to identify challenging years to consider in resource adequacy studies. A variety of approaches for defining and analysing energy droughts can be found in the literature such as those which detect singular events by defining a threshold for renewable energy production (production drought) or how much (net) load is covered by RES (supply drought) (e.g. Raynaud et al., 2018), and those which use statistical methods to assess the risk of an energy drought within a predefined timespan (e.g. Ruhnau & Qvist, 2022). However, there is no clear consensus on which is the best method.

In this study we will present an evaluation of different methods to assess the risk of occurrence of such ‘kalte Dunkelflaute’ events, and validate these methods by comparing with results from detailed hourly simulations, with a focus on the Netherlands and Germany. By applying different detection methods to both existing and projected RES capacity, and using both historical and future climate data from a Pan-European Climate Database, we compare past and future risks posed by energy droughts.  As extreme ‘Dunkelflaute’ events are rare but their impact may be severe, comparing different approaches of how to statistically evaluate these events is an important contribution to evaluating resource adequacy, and assessing the resilience of the future energy.

 

References

  • Raynaud, B. Hingray, B. François & J.D. Creutin (2018). Energy droughts from variable renewable energy sources in European climates. Renewable Energy, 125, 578-589, https://doi.org/10.1016/j.renene.2018.02.130.
  • Ruhnau & S. Qvist (2022). Storage requirements in a 100% renewable electricity system: extreme events and inter-annual variability. Environmental Research Letters, 17(4), 044018, https://doi.org/10.1088/1748-9326/ac4dc8

How to cite: Biewald, B. and Zappa, W.: Evaluation of different methods for detecting 'kalte Dunkelflaute' events with respect to climate change projections, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9590, https://doi.org/10.5194/egusphere-egu24-9590, 2024.

EGU24-10141 | Orals | ERE2.3

Site monitoring and activity detection of wind turbines with Planet and Sentinel-2 satellite data 

Philipp Gärtner, Claudius Wehner, Jan Siegismund, Johannes Albert, and Johannes Zschache

The ongoing energy transition presents us with the challenge of finding sustainable and efficient ways to generate renewable energy. In this context, wind energy plays a decisive role and contributes significantly to increasing the share of renewable energies in the energy mix. Strategic energy planning, effective repowering, decommissioning and the seamless integration of wind energy into the power grid require accurate location information of existing wind turbines. In this work, we present a) the precise, automated, Germany-wide identification and localization of wind turbines using high-resolution planetary data and b) an innovative approach to detect wind turbine activity using Sentinel-2 data. The detection of wind turbine activity is based on the different blade positions, including their shadow position, which is caused by slightly offset recording times of the spectral bands. The change is highlighted and classified using a Convolutional Neural Network. The presentation also discusses possible limitations and peculiarities of the methods used and emphasizes the relevance of remote sensing-based monitoring for the wind energy industry and environmental monitoring.

How to cite: Gärtner, P., Wehner, C., Siegismund, J., Albert, J., and Zschache, J.: Site monitoring and activity detection of wind turbines with Planet and Sentinel-2 satellite data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10141, https://doi.org/10.5194/egusphere-egu24-10141, 2024.

EGU24-11161 | ECS | Orals | ERE2.3

Large-scale green grabbing for wind and solar PV development in Brazil 

Michael Klingler, Nadia Ameli, Jamie Rickman, and Johannes Schmidt

Large-scale wind and solar photovoltaic (PV) infrastructures are rapidly expanding in Brazil. These low-carbon technologies can exacerbate land struggles rooted in historical inequities in land ownership, lack of regulation and weak governance. Here, we trace how green grabbing, i.e. the large-scale appropriation and control of (undesignated) public lands, both formally legal and illicit, for the development of wind and solar PV, has developed in Brazil throughout 2000 to 2021. We find that global investors and owners, mainly from Europe, are involved in 78% of wind and 96% of solar PV parks, occupying 2,148 km2 and 102 km2 of land, respectively. We also show that land privatization is the prevalent land tenure regime for securing access to and control over land, indicating significant transformations of prior (undesignated) public and common land. We conclude that green grabbing is a persistent, critical phenomenon in Brazil, requiring transparency and vigilant monitoring of land claims and tenure modifications.

How to cite: Klingler, M., Ameli, N., Rickman, J., and Schmidt, J.: Large-scale green grabbing for wind and solar PV development in Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11161, https://doi.org/10.5194/egusphere-egu24-11161, 2024.

EGU24-11505 | ECS | Posters on site | ERE2.3

Assessment of a Climate Reanalysis Product for Estimating Hourly Wind Energy Production in Italy 

Esraa Elmaddah, Marco Gaetani, Fabrizio Fattori, and Mario Motta

Recently, the Italian government has revised its national energy and climate plan (NECP) and has significantly increased its objective for wind energy capacity. However, climate change itself can affect the availability of wind resources, due to the increasing frequency of extreme weather conditions, and possible shifts in the mean climate conditions. Meanwhile, RSE has been developing the Meteorological Reanalysis Italian Dataset (MERIDA) to monitor climate variability in Italy over the last 20 years. MERIDA consists of a dynamic downscaling of the ERA5 global reanalysis using the WRF-ARW limited area model and provides hourly data. While MERIDA has a spatial resolution of 7 km, RSE has also developed MERIDA High-resolution for Renewable Energy Sources (HRES) with 4 km spatial resolution. MERIDA HRES represents an upgrade of MERIDA to describe the most relevant meteorological variables for applications related to renewable energy e.g. wind, air temperature, solar radiation.

This work presents an assessment of both MERIDA and MERIDA HRES hourly datasets for the estimation of wind power production in Italy. A comparative analysis has been conducted based on three different types of wind variables, namely: wind speed at 100 m height from MERIDA HRES, 100 m height wind speed extrapolated from MERIDA HRES wind speed at 10 m height, and 100 m height wind speed extrapolated from MERIDA wind speed at 10 m height. A wind power density model has been also developed as part of this work to estimate the wind energy production using wind speed variables. A validation for the results has been conducted vs the hourly actual wind energy output at bidding zone level based on historical data (from ENTSO-E). The results present the impact of both changes in spatial resolution and extrapolation of MERIDA datasets on the expected wind energy output vs the actual energy output.

How to cite: Elmaddah, E., Gaetani, M., Fattori, F., and Motta, M.: Assessment of a Climate Reanalysis Product for Estimating Hourly Wind Energy Production in Italy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11505, https://doi.org/10.5194/egusphere-egu24-11505, 2024.

EGU24-12011 | ECS | Posters on site | ERE2.3

CESM2energy: a modular climate-to-energy pipeline  

Luna Bloin-Wibe, Leonard Göke, Jonas Savelsberg, and Jan Wohland

Transitioning to renewable energy will be instrumental in mitigating the devastating effects of climate change. Because of the many unknowns in the design and dispatch of future energy systems, quantifying climate risk in the energy sector is challenging: in particular, renewable energy production and heating demand is highly reliant on meteorological conditions, which are variable in nature and shifting due to climate change.

It is therefore important to use large samples of renewable generation and demand, for current and future climates, in energy system modeling. However, lacking standardized ways to translate between the climate and energy model world, most existing studies rely on different assumptions and draw from a limited sample of available climate variables.

To this end, we created a modular climate-to-energy pipeline: starting with hourly output from the climate model CESM2, it bias corrects, translates, and scales to the various inputs of energy system models. We base the conversion on open-source tools: GSEE for solar power generation, windpowerlib for wind from climate model levels and demand.ninja for heating and cooling demand. The resulting pipeline ensures consistency of variables, with inputs and outputs tailorable to specific needs.

We use the pipeline to analyze seasonal cycles of energy generation and demand under different weather conditions, for current and future climates deploying the AnyMOD.jl framework for energy system modeling. Because of the modular approach, the pipeline could easily be adapted for other climate models and time-series, providing better evidence for climate-informed energy system planning.

How to cite: Bloin-Wibe, L., Göke, L., Savelsberg, J., and Wohland, J.: CESM2energy: a modular climate-to-energy pipeline , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12011, https://doi.org/10.5194/egusphere-egu24-12011, 2024.

It is widely acknowledged that relying on a single energy source is not viable and a mix of energy sources and carriers is required to achieve carbon neutrality [1]. Hydrogen has come to the forefront of discussion, particularly due to its potential for long-term storage.

Computational models based on mathematical optimization have been widely used in the literature, to better understand the role of hydrogen in energy systems with high shares of variable renewable energy sources (VRES). These models optimize dispatch and investment decisions for multiple energy sources and carriers over several decades. However, to maintain a holistic view of the system with reasonable complexity, it is common to decrease the temporal resolution.

Clustering hourly VRES time-series to a reduced set of representative periods is a particularly popular method in the literature. However, there is an inherent trade-off between short- and long-term dynamics: For example, clustering days enables a more accurate representation of diurnal features compared to clustering hours, although at the expense of considering seasonal trends. In the optimization problem, these features can have a direct impact on investments in short- or long-term storage, and, ultimately in VRES. Moreover, the clustered data suffers from a loss of chronology which is important for modeling long-term (hydrogen) storage and providing accurate operational and investment signals.

To address the research gap raised by [2], the approach of this modeling exercise is to analyze the performance of clustering hours (1) versus clustering days or weeks (2) in the context of storage and VRES investments. The analysis is based on different scenarios for VRES optimized in the energy system model GENeSYS-MOD co-developed by TU Berlin. To improve the shortcomings of (1) and (2), chronological clustering [3] and additional storage constraints [4] are tested and evaluated. Ultimately, the goal is not to derive normative conclusions for time-series aggregation methods and (hydrogen) storage modeling, but instead highlight different configurations and their performance under various settings.

 

[1]        L. Fan, Z. Tu, and S. H. Chan, ‘Recent development of hydrogen and fuel cell technologies: A review’, Energy Reports, vol. 7, pp. 8421–8446, Nov. 2021, doi: 10.1016/j.egyr.2021.08.003.

[2]        L. E. Kuepper, H. Teichgraeber, N. Baumgärtner, A. Bardow, and A. R. Brandt, ‘Wind data introduce error in time-series reduction for capacity expansion modelling’, Energy, vol. 256, p. 124467, Oct. 2022, doi: 10.1016/j.energy.2022.124467.

[3]        S. Pineda and J. M. Morales, ‘Chronological Time-Period Clustering for Optimal Capacity Expansion Planning With Storage’, IEEE Trans. Power Syst., vol. 33, no. 6, pp. 7162–7170, Nov. 2018, doi: 10.1109/TPWRS.2018.2842093.

[4]        L. Kotzur, P. Markewitz, M. Robinius, and D. Stolten, ‘Time series aggregation for energy system design: Modeling seasonal storage’, Applied Energy, vol. 213, pp. 123–135, Mar. 2018, doi: 10.1016/j.apenergy.2018.01.023.

 

How to cite: Reulein, D. and Pinel, D.: Time-Series Aggregation in Energy System Models: Navigating the trade-offs between short-term and long-term dynamics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12640, https://doi.org/10.5194/egusphere-egu24-12640, 2024.

EGU24-13182 | ECS | Posters virtual | ERE2.3

Woody Biomass for the Developing Bioeconomy, a Billion-ton Report Update 

Maggie Davis and Matthew Langholtz

In the pursuit of net-zero targets, the United States Department of Energy releases the fourth in a series of national biomass resource assessments. Building on the studies conducted in 2005, 2011, and 2016, the Billion-ton 2023 (BT23) report, provides an advancement in the understanding of biomass resources in terms of quantity, spatial distribution, and economic accessibility. The goals of this report are to update to latest available input data (e.g., costs, yields, and economic inputs) and ensure equitable access to the latest biomass resource data and that results are findable, accessible, interoperable, and reusable (FAIR) through a data new portal. The assessment unveils nuanced regional variations in biomass availability, ranging from the immediate potential of forest wastes to the maturation of the market for woody energy crops cultivated on agricultural land. This presentation provides an assessment of renewable carbon resources potentially available from the forested and agricultural land bases in the CONUS. The analysis of biomass resources extends to forested landscapes, assessed using the Forestry Sustainability and Economic Analysis Model (ForSEAM). Additional biomass resources on agricultural land are modeled using the Policy Analysis System Model (POLYSYS), a partial-equilibrium linear programming model with a focus on the agricultural producer response. In collaboration with the U.S. Forest Service (USDA-FS), waste-based woody resources are assessed using Forest Inventory and Analysis (FIA) data and the Bioregional Inventory Originated Simulation Under Management (BioSUM) model. BioSUM models two case studies to determine the potential for trees and other waste resources to be harvested from forests, fostering resilience against the growing threat of wildfires. Throughout these analyses, sustainability constraints are incorporated including the net regeneration of forested stands, limitations on harvesting on steep slopes, and other good practices that would need to be applied based on local conditions. By providing detailed insights into woody biomass suitability for energy production, this research lays the groundwork for near-term woody biomass resource potential and a mature-market potential contributing to a developing bioeconomy. This comprehensive analysis underscores the pivotal role of biomass resources in steering the U.S. toward net-zero targets.

How to cite: Davis, M. and Langholtz, M.: Woody Biomass for the Developing Bioeconomy, a Billion-ton Report Update, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13182, https://doi.org/10.5194/egusphere-egu24-13182, 2024.

EGU24-15062 | ECS | Orals | ERE2.3

Temporally compounding energy droughts in European electricity systems with hydropower 

Lieke van der Most, Karin van der Wiel, Winnie Gerbens-Leenes, René Benders, and Richard Bintanja

As renewable energy capacities continue to grow (rapidly), the European electricity system will become vulnerable to extreme events in the form of energy droughts—periods of low production coinciding with high demand. In this work, we use a large model ensemble of 1600 years of daily climate data in conjunction with an energy production and demand modelling framework and consider present-day installed capacities to compute the full distribution of renewable electricity production and demand in the present-day climate. This approach enables us to examine in detail the specific events at the tail of the distribution that pose the highest risks to energy security.

In particular, this study focuses on energy droughts occurring once every ten years in six European countries: Sweden, Norway, Italy, Spain, France, and Switzerland, chosen because of their specific renewable energy mix including hydropower. We analyze energy drought events and their corresponding meteorological conditions and find that energy droughts result from processes that cause (temporally) compounding impacts in the energy and meteorological system. These processes can turn what might have been short-term droughts into prolonged, cumulative energy crises. For instance, low reservoir inflows in spring quadruple the chance of prolonged energy droughts: reduced snowpack and rainfall lower hydro-availability but also dry-out subsoils, increasing the chance of heatwaves and thereby extending the energy problems into summer.

We identify and evaluate three compounding energy/climate conditions and quantify the associated risks. These results can inform the energy modelling community where high-risk meteorological conditions can be applied in power system models to optimize and analyze the robustness of future energy system designs, and provide insights on the specific characteristics of the risks of multiyear energy droughts to policymakers and energy companies.

How to cite: van der Most, L., van der Wiel, K., Gerbens-Leenes, W., Benders, R., and Bintanja, R.: Temporally compounding energy droughts in European electricity systems with hydropower, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15062, https://doi.org/10.5194/egusphere-egu24-15062, 2024.

Large-scale energy system modelling plays a crucial role in the debate on energy system decarbonisation. It is common to use a bidding zone representation to model the European energy system due to the structure of the electricity market. However, this may underestimate infrastructure constraints at higher spatial resolutions. This question has been investigated in the literature, while methods for aggregating highly resolved data remain a research gap. In this study we explore various spatial resolutions using the sector-coupled energy system model Balmorel with a focus on the Danish energy system. The modelling framework will encompass detailed geospatial data of existing Danish power plants in combination with the atlite module for generating variable renewable energy (VRE) production profiles at different geographical locations. Utilising the further developed modelling framework in Balmorel, the impact of applying various spatial resolutions is thus investigated from a bidding zone, NUTS2, NUTS3, to municipal spatial resolution. Preliminary results indicate that transmission costs are underestimated at low spatial resolution. However, they remain a small part of total system costs at very high spatial resolution. Large operational differences are observed, which will be investigated further. These results will be discussed considering spatial aggregation methods and used to inform further research on a similar investigation at the European scale to advance the modelling of sector-coupled energy system models with high penetrations of VRE.

 

How to cite: Rosendal, M.: Analysis of Various Spatial Resolutions for Modelling Sector-Coupled Energy Systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15405, https://doi.org/10.5194/egusphere-egu24-15405, 2024.

EGU24-15765 | Posters on site | ERE2.3

Assessing the Spatiotemporal Variability and Complementarity of Renewable Energy Resources across Europe 

Amna Bibi, Ben Marzeion, Muhammad Shafeeque, and Gerald Lohmann

Europe's energy transition towards renewable sources is imperative for achieving sustainability and mitigating climate change. However, the intermittency of solar and wind power necessitates a detailed evaluation of their combined potential. This study analyzes the spatiotemporal distribution and variability of solar and wind power resources across Europe from 1979-2022, using ERA5 reanalysis data.

Empirical Orthogonal Function (EOF) analysis is used to characterize the spatiotemporal patterns of variability in irradiance and wind speed up to multidecadal timescales. Also, the variance of the estimates of the capacity factor (CF, i.e., electricity generation normalized to the installed capacity) is compared with EOF patterns.

Results show that the leading three modes of EOF represent the most variance in spatial distribution of irradiance and wind speed over Europe, with significant interannual and interdecadal fluctuations influencing spatiotemporal distribution. The temporal variance for offshore and onshore wind exhibits larger spatial heterogeneity. The spatial heterogeneity of the variance of solar CF is lower than that of wind power CF, but its amplitude is much higher in most regions. There is a negative linear correlation between the variance and mean of CF for both solar and wind power.

Southern Europe shows the lowest intermittency in solar power, while eastern and northern Europe exhibit a lower intermittency of onshore wind. Offshore wind potential is high over the Norwegian and Mediterranean Seas. We also identify areas of maximum complementary between solar and wind power resources, attempting to use large-scale datasets and established knowledge of patterns of climate variability to fulfill local-scale renewable energy requirements best. Future research will focus on developing advanced hybrid models to integrate diverse renewable energy sources, exploring their synergistic potentials.

How to cite: Bibi, A., Marzeion, B., Shafeeque, M., and Lohmann, G.: Assessing the Spatiotemporal Variability and Complementarity of Renewable Energy Resources across Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15765, https://doi.org/10.5194/egusphere-egu24-15765, 2024.

EGU24-17971 | ECS | Posters on site | ERE2.3

CFD, a radiative model, and a plant model to capture the interactions between solar panels, the atmosphere, the soil, and the plants in agrivoltaic configurations. 

Joseph Vernier, Sylvain Edouard, Baptiste Amiot, Mike Van Iseghem, Martin Ferrand, Didier Combes, Guillaume Schuchardt, and Patrick Massin
Currently, our understanding of the impact of agrivoltaic systems on the crops is limited. The presence of panels modifies the micro-climate and therefore the radiative, thermal, and aeraulic exchanges between the crop and its surrounding (S. Edouard, 2022). These modifications can lead to a loss of agricultural production, but also to a crop protection against meteorological events. Crop models, such as DSSAT, are not suitable to study the impact of solar panels on crop growth as spatial and temporal averages in the models hide spatial heterogeneities caused by the panels, and the sub-daily phenomena are not simulated. Computational fluid dynamic (CFD) allows high-fidelity simulations of multi-physics problems on different time and length scales (such as thermal hydraulics in power plants, or the drag of a wind farm). First CFD simulations applied to agrivoltaics have been carried out by (S. Zainaly, 2023), and by (H. J. Wiliams, 2023). Through Joseph Vernier’s PhD thesis, EDF R&D has initiated CFD modeling applied to agrivoltaics.
 
The CFD solver code_saturne simulates the flow over the panels, as well as the radiation, the temperature, and the humidity fields. Moreover, a 2 layers force-restore soil model computes the energy and the water exchanges between the soil and the atmosphere. The effect of the micro-climate on the photosynthesis and the plant stomatal resistance must be considered to accurately predict the plant growth. That is why, the soil-plant-atmosphere continuum model (A. Tuzet, 2003) has been implemented in code_saturne and a simplified study case composed of four solar panels has been built. First simulations of the modifications of the micro-climate by the solar panels and how it impacts the crops are very promising. Indeed, spatial heterogeneities are well simulated for the radiation, and the soil temperature (Figure 1-4), as well as for the wind speed (Figure 5, 6), the plant temperature, the photosynthesis, and the evapotranspiration. Simulations of the impact of shading on the soil water balance reveals that the plant’s energy balance is locally modified in a complex fashion that depends on the agrivoltaic power plant geometry. Water stress is considered, and it interferes with the plant's ability to photosynthesize and to transpire. Thanks to the coupling of code_saturne and the soil-plant-atmosphere continuum model, the plant state is simulated along the day for different weather conditions and agrivoltaic configurations. This is a first step towards a deeper understanding of the physical interactions within a photovoltaic system.

How to cite: Vernier, J., Edouard, S., Amiot, B., Van Iseghem, M., Ferrand, M., Combes, D., Schuchardt, G., and Massin, P.: CFD, a radiative model, and a plant model to capture the interactions between solar panels, the atmosphere, the soil, and the plants in agrivoltaic configurations., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17971, https://doi.org/10.5194/egusphere-egu24-17971, 2024.

EGU24-18667 | ECS | Orals | ERE2.3

Impact of climate change on high-VRE optimal mixes and system costs: the case of France. 

Joan Delort Ylla, Alexis Tantet, and Philippe Drobinski

High-Variable Renewable Energies (VREs) power systems are becoming a cornerstone of climate change mitigation policies across Europe. At the same time, committed and potential climate change will impact energy systems as a whole, both from the supply and demand side. Current power systems are expected to change drastically in the future, in particular in terms of VRE penetration. Finding the best mix for a given country is a complex problem that depends on multiple social, economical and political criteria. Instead of prescribing future capacities, economically optimal VRE mixes that ensure system adequacy can be used. We focus in this study on the impact of climate change on these optimal VRE mixes, as well as on the associated system costs. The study is narrowed to the case of France, which is a highly temperature sensitive country with high VRE potential resources. An ensemble of six model pairs from the EURO-CORDEX (CMIP5) project is used to obtain the meteorological variables of interest under different levels of climate change. The open source software e4clim is used to determine the economically optimal mixes. Socioeconomic scenarios of electrification are derived to study the effect of an increased base load and temperature sensitivity. We find that for the case of France increasing climate change tends to decrease demand. The PV resource is not affected significantly whereas the wind resource decreases over the whole country and up to 10 % in some regions. We show that these impacts lead to changing optimal VRE mixes. Although the installed photovoltaic (PV) capacity is not affected by climate change, except for its geographic distribution under some socioeconomic scenarios, so does the installed wind capacity. No matter the socioeconomic scenario, installed wind capacity is found to be the adjustment variable when demand decreases due to climate change: even though the wind capacity factor decreases, less capacity needs to be installed. In parallel, increasing levels of climate change lead to decreased system total costs: less VRE generation capacity is installed and generation costs for the dispatchable producers are decreased. These cost differences are up to 10 % and amount up to 6 G€ depending on the socioeconomic scenario considered. We finally find that the system marginal cost is not significantly affected by climate change. Underestimating future climate change in planification could thus lead to stranded wind farm assets up to 10 % of the installed fleet, corresponding to up to a 2 G€ loss. If stranded assets are avoided by anticipating the right climate change scenario, then adverse impacts of climate change are found to be minimal, since the cost for dispatchable producers tends to decrease and the system marginal cost is not affected. If only economically optimal VRE mixes were considered here, those can then be put under suboptimal climatic and socioeconomic conditions, paving the way to take into account the uncertainty related to climate change and socioeconomic development when dealing with VRE mix planification issues.

How to cite: Delort Ylla, J., Tantet, A., and Drobinski, P.: Impact of climate change on high-VRE optimal mixes and system costs: the case of France., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18667, https://doi.org/10.5194/egusphere-egu24-18667, 2024.

EGU24-18680 | ECS | Orals | ERE2.3

Optimising Submarine Cable Routes from Offshore Windfarms – Site Suitability Mapping 

Kevin Walsh, Paul Holloway, and Aaron Lim

The Irish Government’s Climate Action Plan aims to increase renewable energy generation capacity to 22GW by 2030, with at least 5GW of this to be produced by offshore wind. The potential to harness and develop this resource is significant; however not all areas offshore are suitable. Moreover, not all routes from windfarms to land are suitable for the submarine cables needed to transfer the energy produced offshore back to the onshore grid.

This research utilizes geospatial analysis to identify the optimal route selection for offshore export cables. The area under consideration for this research encompasses the South and West coasts of Ireland in the North Celtic Sea and Eastern Atlantic Ocean, areas under intense development for offshore wind, particularly floating wind platforms.

To achieve this, a geospatial repository of publicly available data was compiled to ensure the key features related to cable route feasibility were included in the spatial analysis. These layers included bathymetric, geological, and ecological data, as well as information on human activities in the area, to assess the potential hazards to a submarine cable within a particular region. Each variable was assessed as to its importance in the route selection model using criteria weights derived from the Analytical Hierarchical Process and expert opinion of a panel of industry representatives. The resulting data layers were combined into a suitability map of the seabed using a Weighted Overlay Analysis.

Individual offshore wind sites and coastal landfall sites were selected based on proposed developments. GIS route selection methods were then implemented, principally the least-cost path algorithm, to identify the optimal route.

The combined criteria map produced in this project classifies regions off the South and West coasts of Ireland into zones of suitability for cable routes and highlights the main areas along the coast most appropriate for cable landfall sites.  By using automated route selection tools in GIS along the suitability map surface, realistic paths along the seabed can be quickly designed to allow for adequate burial of the cable, and avoidance of obstacles, hazards and zones of exclusion.

The findings of this research indicate that distance from existing coastal substations is a key factor in terms of the economic viability of a cable route. Many windfarms will require more than one export cable, and with several windfarm proposals within the same coastal region, bottle necks at suitable landfall sites may be expected.

The results of the study provide a useful tool for policy makers and developers in the planning stage. In a broader context, these findings can be upscaled, customised and applied at a national level for other countries to allow a systematic approach to offshore renewable energy development.

How to cite: Walsh, K., Holloway, P., and Lim, A.: Optimising Submarine Cable Routes from Offshore Windfarms – Site Suitability Mapping, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18680, https://doi.org/10.5194/egusphere-egu24-18680, 2024.

EGU24-18985 | ECS | Orals | ERE2.3 | Highlight

Can Norway save the European Union's hydrogen ambition for 2030? 

Isabelle Viole, Koen van Greevenbroek, and Claudia Cheng

How competitive can Norway – one of the main natural gas suppliers to the European Union (EU) – be at exporting hydrogen to the EU? We explore three scenarios in which Norway’s hydrogen export market may develop: A Business-as-usual, B Moderate Onshore, C Accelerated Offshore. Applying a sector-coupled energy system model, we examine the economic, social and environmental implications of each scenario. Given a variety of cost assumptions in shipping, CCS and electrolysis, the pathways result in wide ranges of potential costs of hydrogen from 2-7€/kg hydrogen. In the cheaper scenarios A and B we identify roadblocks in social acceptance in either the expansion of onshore wind turbines, or in resistance against CCS technologies. Environmental trade-offs in land use change follow suit. Any of the pathways discussed requires fast investments in the necessary infrastructure paired with measures to increase social acceptance and to alleviate environmental impacts. Nonetheless, we show that Norway could supply a significant share of the EU’s hydrogen demand in the near-term future.

How to cite: Viole, I., van Greevenbroek, K., and Cheng, C.: Can Norway save the European Union's hydrogen ambition for 2030?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18985, https://doi.org/10.5194/egusphere-egu24-18985, 2024.

EGU24-19090 | ECS | Orals | ERE2.3

How important are hydrogen imports for European carbon neutrality? 

Koen van Greevenbroek, Johannes Schmidt, and Marianne Zeyringer

Hydrogen could play a crucial role in Europe's transition to carbon neutrality by 2050. However, the size and scope of the upcoming hydrogen sector is subject to great uncertainty due to unknown future costs, technological developments and competition with other energy carriers. The prospects of hydrogen imports from outside the EU is possibly subject to even greater uncertainty. Are hydrogen imports needed at all? Are they an essential element of the green transition? In the present work we use a multi-horizon energy system optimisation framework to investigate the rationale for EU hydrogen imports. In particular, we analyse when hydrogen imports may alleviate the most critical bottlenecks in achieving net carbon neutrality by 2050. The main bottlenecks of interest are rapid growth in renewable energy and hydrogen production. To ensure robustness of the results, we use near-optimal methods to map out a large variety of transition pathways under a number of different political and technological scenarios. The pathways are evaluated on cost and land-use impact inside Europe as well as potential upstream impacts of imported hydrogen. Using this holistic approach allows us to uncover when hydrogen imports are compelling and when they are dubious. 

How to cite: van Greevenbroek, K., Schmidt, J., and Zeyringer, M.: How important are hydrogen imports for European carbon neutrality?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19090, https://doi.org/10.5194/egusphere-egu24-19090, 2024.

EGU24-19829 | ECS | Posters virtual | ERE2.3

Spatiotemporal evolution and renewable energy potential in coal regions in transition 

Konstantina Pyrgaki, Pavlos Krassakis, Andreas Karavias, Theodoros Zarogiannis, Evangelia Zygouri, Anna Mpatsi, and Nikolaos Koukouzas

The WINTER project, funded by the EU, aims to develop a web GIS interactive platform that will be used as a tool for the management of coal regions in transition. The platform will guide and engage stakeholders by sharing best practices and addressing transition challenges in pilot regions at different transition stages.  The applied methodology involved a three-step process: 1) developing a geodatabase to import and standardize geospatial datasets; 2) training and implementing a Machine Learning (ML) approach [1]; and 3) identifying and quantifying land cover (LC) changes from 2018 to 2021. Particularly in Western Macedonia (Greece), the Amynteo mine, illustrated a green transition (Figure 1), converting mining areas to bare soil, vegetation and water bodies, indicating strong reclamation potential. In contrast, the Ptolemaida mine, still operational, illustrated minimal land cover changes. In Poland and specifically, in Konin region results highlighted mining expansion, affecting agricultural and wetland areas. On the other hand, the Kazimierz mine, which is already at a closure phase, exhibited a significant green transition, with a marked increase in vegetation land cover. 

The following step was the assessment for the potential for Renewable Energy Source (RES) implementation utilizing, open-source geospatial datasets, considering factors like elevation/slope, wind speed, solar radiation, and land cover/land use were used. Scenarios were designed to identify preliminary suitable areas for Photovoltaic (PV) and Wind Parks (WP) installations. In Western Macedonia, potential sites were identified adjacent to the Ptolemaida mine limits, with a significant area suitable for PV parks. In Konin, the analysis within mine boundaries revealed similar suitability for PV and WP, showing the highest potential for RES implementation. Specifically, in Western Macedonia, the potentially suitable areas for PV was higher, up to 34% of the total studied area, in contrast to the 12%-18% range observed in Konin's mines. Additionally, the potentially suitable sites for WP in Western Macedonia seem to be related due to geomorphological differences, whereas in Konin, the suitability analysis based on results within the boundaries of the open-pit mine.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101057228 (WINTER).

[1] Krassakis, P.; Karavias, A.; Nomikou, P.; Karantzalos, K.; Koukouzas, N.; Kazana, S.; Parcharidis, I. Geospatial Intelligence and Machine Learning Technique for Urban Mapping in Coastal Regions of South Aegean Volcanic Arc Islands. Geomatics 2022, 2, 297-322. https://doi.org/10.3390/geomatics2030017

How to cite: Pyrgaki, K., Krassakis, P., Karavias, A., Zarogiannis, T., Zygouri, E., Mpatsi, A., and Koukouzas, N.: Spatiotemporal evolution and renewable energy potential in coal regions in transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19829, https://doi.org/10.5194/egusphere-egu24-19829, 2024.

EGU24-19844 | Orals | ERE2.3

Analysis of Land Use Change at Wind Turbine Sites 

Christian Mikovits and Thomas Öberseder

A wind power plant's development causes a range of disturbances, both short-term and long-term. Wind turbine pads, access roads, substations, service buildings, and other equipment that physically occupy land or produce impermeable surfaces are examples of these disruptions. Development in forested areas, where more land must be removed around each turbine, is linked to extra direct impacts. Although the land cleared around a turbine pad does not produce impermeable surfaces, the quality of the ecosystem may be significantly degraded as a result of this alteration.

This work includes the outcomes derived from a sequence of data analytics. The analyses entail aggregating unprocessed data obtained from Copernicus Sentinel-2 satellite images covering the timeframe from 2015 to 2023. The development of algorithms tailored to distinct regions (such as EU countries and sub-regions) to identify alterations, together with the subsequent statistical examination of the alteration data, are essential elements of this procedure. The change dataset has a spatial resolution of 10m x 10m, which is the same as the input data from Sentinel-2. It is a binary raster dataset that visually shows the changes happening below and near the wind turbine sites that were built between 2015 and 2023. The statistical analysis includes the evaluation of this data and the examination of the changing raster, land-cover data, the biogeographical area, and terrain data. The statistical calculations are conducted for both individual wind turbines and wind parks comprising many wind turbines. 

How to cite: Mikovits, C. and Öberseder, T.: Analysis of Land Use Change at Wind Turbine Sites, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19844, https://doi.org/10.5194/egusphere-egu24-19844, 2024.

Renewable energies (RES) infrastructure may imply local benefits and burdens. Local benefits might be, e.g., energy autonomy or trade tax income. Local burdens may be reflected, e.g., in house price losses or local opposition by citizens. From a justice perspective, this leads to our overarching research question: What would a just spatial distribution of local burdens and benefits of RES infrastructure look like and how could distributive spatial justice be achieved? With respect to the first part of the question (what would be a just distribution of benefits and burdens?), different answers may exist depending on one's understanding of distributive justice. With regard to the second part of the question (how to achieve a just distribution of benefits and burdens?), there are basically two possible approaches. Firstly, the distribution of local benefits can be addressed. By modifying the institutional framework and/or the spatial infrastructure deployment the spatial distribution of benefits can be adjusted to achieve a distribution of benefits and burdens being considered as just. Secondly, the distribution of local burdens can be targeted and affected in order to achieve a distribution of benefits and burdens considered as just. That is the focus of this paper. We assume local burdens being solely influenced by infrastructure deployment and local benefits being spatially equivalent to the burdens, thus not requiring separate consideration.

To examine our overarching research question, we use a numerical optimization model. We apply the model to the future spatial deployment of onshore wind power and utility scale solar photovoltaics (PV) in Germany in a fully renewable system. We optimize the deployment for given energy production targets with respect to a cost-effectiveness criterion and with respect to various alternative spatial distributive justice understandings. These relate to the equality principle, ability principle, and benefit-principle. By doing so, we shed light on three sub-questions: (1) Can spatial distributive justice of the RES deployment be improved and if so, to what extent? Our results show that, due to regional RES potential limitations, perfect justice cannot be achieved for any of the assumed concepts of justice. But our results also show that the current infrastructure allocation can be assessed as relatively unjust with regard to all assumed concepts of justice, and considerable improvements in justice would be possible by redistributing deployment in space. (2) What relevance do different normative assumptions have for the spatial distributional justice of the RES deployment? Our results reveal that the justice assessment of an allocation depends largely on the understanding of justice that is assumed. In addition, our optimizations demonstrate that it is easier to establish distributive justice between larger and fewer regions than between smaller and more regions. (3) To what extent are there trade-offs between pursuing spatial distributive justice and cost-effectiveness? We find that optimizing the RES deployment by levelized costs of electricity (LCOE) is comparatively unfavorable with respect to the assumed justice concepts. In turn, optimizing the spatial allocation of RES deployment by the assumed justice concepts increases LCOE by 1%-14%, compared to the cost-optimal allocation.

How to cite: Lehmann, P. and Reutter, F.: Spatial distributive justice for onshore wind power and utility-scale solar PV deployment – Optimizations for the case of Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19996, https://doi.org/10.5194/egusphere-egu24-19996, 2024.

EGU24-20555 | Posters on site | ERE2.3

The Influence of Meteorological Variables on Energy Demand in the Federal District of Brazil 

Helber Gomes, Dirceu Herdies, Luiz Fernando Santos, João Augusto Hackerott, Mário Quadro, Fabricio Daniel dos Santos Silva, Robinson Semolini, Bruno Dantas Cerqueira, and Djanilton Henrique Moura Junior

The effects of climate change are present in all segments of society in general, and especially in the energy segment. Brazil plays a leading role in the use of renewable energy, with the majority of its matrix coming from renewable sources. In this sense, evaluating the impact of meteorological variables on the injected energy load is fundamental for the efficient use of energy. The present study aims to analyze the influences of meteorological variables on the energy load demand in Brasília - Federal District, Brazil. We analyzed observed data from the National Institute of Meteorology (INMET) weather station, reanalysis data from the National Center for Environmental Prediction (NCEP), reanalysis from the European Center for Medium-Range Weather Forecast (ECMWF), Modern-Era Retrospective Analysis for Research and Application Aerosol Reanalysis (MERRA-2) and South American Mapping of Temperature (SAMeT). Pearson's correlation coefficient was used to quantify the linear relationship between the observed data from the meteorological station (INMET) and the monthly load injected in Brasília in the period 2016-2022. Subsequently, statistical metrics, commonly used for model checking, were applied to regularly spaced global numerical model datasets with assimilation: CFSR (NCEP), ERA5 (ECMWF), MERRA2 (NASA), and SAMET (INPE). A high direct correlation of the injected monthly load with the monthly averages of maximum and average temperatures (0.65 and 0.51), respectively, and an inverse correlation with the observed average relative humidity (-0.50) was noted. Furthermore, the representativeness of temperatures from the data sets was investigated, aiming to expand the analysis to other regions that do not have meteorological station data. In validating the maximum and average temperature, it was possible to identify a high representative potential of the sets covered. Highlights include SAMET and ERA5, which presented the highest correlation coefficients (higher than 0.90) and standard deviation proportional to observational data.

How to cite: Gomes, H., Herdies, D., Santos, L. F., Hackerott, J. A., Quadro, M., Silva, F. D. D. S., Semolini, R., Cerqueira, B. D., and Junior, D. H. M.: The Influence of Meteorological Variables on Energy Demand in the Federal District of Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20555, https://doi.org/10.5194/egusphere-egu24-20555, 2024.

EGU24-21977 | ECS | Posters on site | ERE2.3

Two million European single-family homes could abandon the grid by 2050 

Max Kleinebrahm, Jann Michael Weinand, Elias Naber, Russell McKenna, Armin Ardone, and Wolf Fichter

Rising energy procurement costs and declining capital costs for renewable technologies are provoking interest in self-sufficiency for individual buildings. In this study, we evaluate the potential of self-sufficient energy supply for 41 million freestanding single-family buildings in the European building stock under current and future (2050) conditions. We employ spatial microsimulation to derive a synthetic building stock, identify 4000 representative buildings and calculate weather-robust cost-minimal energy systems using a high-performance computing cluster. Subsequently, we train surrogate models to transfer the optimization results to the entire European building stock. Our analyses show that buildings in regions with low seasonality, high solar radiation and high electricity procurement costs have high potential for self-sufficiency. Under current techno-economic conditions, 53% of the 41 million buildings are technically able to supply themselves independently from external infrastructures by only using local rooftop solar radiation, and this proportion could increase to 75% by 2050. By paying a premium of up to 50% compared to grid-dependent systems with electrified heat supplies, building owners could make over two million buildings fully energy self-sufficient by 2050.

How to cite: Kleinebrahm, M., Weinand, J. M., Naber, E., McKenna, R., Ardone, A., and Fichter, W.: Two million European single-family homes could abandon the grid by 2050, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21977, https://doi.org/10.5194/egusphere-egu24-21977, 2024.

Energy communities (ECs) are expected to play a major role in the European Energy transition. However, quantitative evidence shows that these only represent a minor share of the installed capacity compared to commercial large scale installations. We argue that understanding better the conditions that facilitate of ECs emergence, will contribute to develop adequate strategies to foster their creation. In previous research we conducted an exploratory data analysis to understand the relation between the availability and quality of variable renewable energy sources (VRES) and ECs (Ramirez Camargo et al., 2023). This was done by calculating 38 indicators of VRES availability and quality for NUTS3 regions derived from four decades of ERA5 data, together with a data set of energy cooperatives (most common organizational form of ECs) as a proxy for ECs with less than 1,000 entries. With the publication of an extensive data set of citizen-led energy initiatives, agglomerating all sorts of ECs and with more than 10,000 entries (Wierling et al., 2023), we replicated the previously proposed methodology. The main results from previous research hold at the continental level:  There is a slight predominance of citizen-led energy initiatives where wind resources are high and opposite results for solar resources. Nevertheless, the considerably higher data availability allows for a detailed analysis at the country level. We observe that while countries with large numbers of citizen-led energy initiatives, such as Germany, drive what we observed at the continental level, there are countries such as Denmark and Ireland with high positive correlation between citizen-led energy initiatives and wind power capacity factors. There are also clear exceptions to the rule, such as the Czech Republic, with a high positive correlation to solar resources that reaches 0.731. At the country level, just as at the continental level, we see that clusters of citizen-led energy initiatives develop where VRES availability is high but it also becomes more evident that there are large differences in the concentration of citizen-led energy initiatives between NUTS3 regions of individual countries. Finally, we see a large unexploited potential for development of ECs in the regions of the continent that are rich in solar resources.

Ramirez Camargo, L., Lode, M., & Coosemans, T. (2023, Januar 13). Assessing the relevance of renewable energy resources availability for the existence of Energy Cooperatives in Europe. Volume 29: Closing Carbon Cycles – A Transformation Process Involving Technology, Economy, and Society: Part IV. Applied Energy Conference 2022. https://doi.org/10.46855/energy-proceedings-10327

Wierling, A., Schwanitz, V. J., Zeiss, J. P., von Beck, C., Paudler, H. A., Koren, I. K., Kraudzun, T., Marcroft, T., Müller, L., Andreadakis, Z., Candelise, C., Dufner, S., Getabecha, M., Glaase, G., Hubert, W., Lupi, V., Majidi, S., Mohammadi, S., Nosar, N. S., … Zoubin, N. (2023). A Europe-wide inventory of citizen-led energy action with data from 29 countries and over 10000 initiatives. Scientific Data, 10(1), Article 1. https://doi.org/10.1038/s41597-022-01902-5

How to cite: Ramirez Camargo, L. and Lode, M. L.: Evaluating the relevance of the availability of variable renewable energy resources for the existence of citizen-led energy initiatives in Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22066, https://doi.org/10.5194/egusphere-egu24-22066, 2024.

EGU24-1601 | ECS | Orals | ERE2.4

The exploitation of resources created by human beings, an additional alternative for reducing emissions 

Isabel C. Gil García, Ana Fernández Guillamón, Adela Ramos Escudero, and Ángel Molina García

The urgency of mitigating emissions on our planet drives the exploration of various sources of clean energy. Natural resources, such as solar radiation, wind and water, provide the opportunity to transform them into forms of sustainable energy. In recent decades, the advancement of wind technologies has led the sector to reach full maturity, encompassing both large-scale wind energy generation in marine and terrestrial environments and the implementation of mini-wind solutions. However, we often underestimate the human activities, production processes or technological innovations that generate clean resources, without fully taking advantage of their potential. In this context, the central purpose of this work is to take advantage of wind gusts caused unnaturally and, through small wind power, convert them into clean energy. The proposal is organized in three phases: in the first, a data analysis is carried out that involves taking in situ samples of wind speed and an evaluation of wind potential; In the second stage, the energy conversion is carried out, selecting the mini-wind technology through multi-criteria evaluation methods and determining the amount of electrical energy to be generated; Finally, in the third phase, an analysis of results is carried out that covers different scenarios evaluated according to indicators such as the electricity consumption to be replaced, the quantification of avoided emissions and an economic analysis.

Acknowledgements: Project PID2021-126082OB-C22 funded by MICIU/AEI/10.13039/501100011033 and FEDER, EU

How to cite: Gil García, I. C., Fernández Guillamón, A., Ramos Escudero, A., and Molina García, Á.: The exploitation of resources created by human beings, an additional alternative for reducing emissions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1601, https://doi.org/10.5194/egusphere-egu24-1601, 2024.

EGU24-3165 | Orals | ERE2.4

Driving energy systems with synthetic electricity prices 

Andreas Efstratiadis and Georgia-Konstantina Sakki

The electricity market across Europe, which is key driver of energy systems, has been subject to structural changes in the last years, in order to favor the penetration of renewables and foster decarbonization. A substantial guiding principle was the establishment of the Target Model, configurating a new era of the energy as a trading product. The corollary of this is that the market price became more dependent on socioeconomic disturbances and highly unpredictable events, such as financial, geopolitical and health crises. As a consequence, the variability of electricity prices has been substantially increased across all scales (intra-day, seasonal and long-run). In order to embed this major facet of uncertainty within energy systems modelling, we introduce a generic stochastic simulation framework to represent the market dynamics as a random process across scales. Key challenge is capturing the behavior of electricity prices that are characterized by significant peculiarities, such as volatility and spikes, as well as double periodicity, across seasons and within the intraday cycle. Further challenges are induced by the limited statistical information under the Target Model structure, and the need to implement within the synthetic data abnormal yet persistent shifts, as observed during the recent energy crisis. To stress-test our methodology, we simulate the quite different statistical response of the electricity prices in Greece and Portugal – two countries with similar economic conditions, fiscal compliance, and financial sector development.

How to cite: Efstratiadis, A. and Sakki, G.-K.: Driving energy systems with synthetic electricity prices, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3165, https://doi.org/10.5194/egusphere-egu24-3165, 2024.

Experiences with open-pit mine flooding in German lignite mining regions show that hydrogeochemical processes can become critical ecological and economic factors for the realisation of Pumped Hydropower Storage (PHS) projects. Depending on sulphide and oxygen availability as well as buffering and dilution processes, acid mine drainage and increased sulphate and metal concentrations can have negative impacts on ecosystems and groundwater resources as well as the installed PHS infrastructure. As part of the ATLANTIS project, this study aimed to quantify changes in water composition in the lower storage reservoir resulting from PHS operation under different hydrogeochemical boundary conditions.

For the present parameter study, data sets on hydrochemistry, hydrogeology and morphology of flooded German lignite mines were used to develop a numerical hydrochemical reaction path modelling framework. The chemical calculations were realised with PHREEQC (Parkhurst and Appelo, 2013), while the input and output data were managed via the Python-based simulation framework and PHREEQPY (Müller, 2022). The implemented parallelised workflow made it possible to analyse and evaluate more than 12,000 parameter combinations for various hydrogeological baseline scenarios. The influencing factors considered in these scenarios include the initial flooding of the open-pit mines, source terms due to precipitation, groundwater inflow and surface run-off, mineral availability in the sediments and the pumping cycles between the lower and upper storage reservoirs of the PHS installation.

The simulation results show that the volume of water migrating between the lower reservoir and its adjacent aquifers during the pumping cycles is too small to influence the water quality of the reservoir on the short term. The long-term availability of buffer capacities in the reservoir and the present mine waste dumps determine the eventual development of acidic or pH-neutral mine water. Sulphate concentrations are mainly influenced by dilution processes, what underlines the relevance of considering additional source and sink terms. Depending on these as well as the availability of oxygen and quantities of sulphide present in the adjacent sediments, the time required to achieve a chemical equilibrium in the lower storage reservoir varies from a few weeks to several years.

In summary, the operation of pumped storage power installations in former open-pit lignite mines can be safely realised if sufficient acid buffer capacities are available and dilution through additional water in- and outflows is sufficiently high.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).

Literature

Müller, M. (2022): PhreeqPy - Python Tools for PHREEQC. https://www.phreeqpy.com/. Last accessed on 09.01.2024.

Parkhurst, D. L., & Appelo, C. A. J. (2013). Description of input and examples for PHREEQC version 3—a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. US geological survey techniques and methods, 6(A43), 497.

How to cite: Schnepper, T., Kühn, M., and Kempka, T.: Pumped hydropower storage operation in open-pit lignite mines does not compromise the pit lake and groundwater chemistry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3947, https://doi.org/10.5194/egusphere-egu24-3947, 2024.

EGU24-4728 * | ECS | Posters on site | ERE2.4 | Highlight

Water and energy storage in the European Union: current situation and future challenges 

Emanuele Quaranta and Alberto Pistocchi

Water storage is a key element in the Water-Energy-Food-Ecosystem Nexus (WEFE Nexus). Water storage systems can be designed in different ways and for serving several purposes. Water storage is also associated to energy storage, when there are turbines that can produce energy (hydropower) from the stored water. More than 95% of the current energy storage in the European Union (EU), and worldwide, is stored in artificial reservoirs behind dams. In the EU there are 4491 large dams according to the ICOLD 2023 register of dams and 40% are for multiple uses. Overall, 48% of EU’s large dams are powered. The theoretical potential of energy storage Es in hydropower reservoirs (Es = k·h·V, V=reservoir volume in m3, h=head in m, k=coefficient for the units) is some tens of TWh in the EU. The theoretical potential so calculated is 9 TWh for pumped-hydropower storage (PHS) plants. However, the real technical storage capacity is much less than the theoretical one (1200 GWh in PHSs).

As the impacts of climate change have considerable effects on people and ecosystems, which are exacerbated by a rising demand for water due to population and economic growth, higher temperatures and decrease in precipitation in certain regions, water&energy storage capacity needs to increase in the future, and should consider the interdependence of water, energy and food security and ecosystems – water, soil, and land. In this contribution, the current state-of-the art of PHSs in the EU is discussed and the challenges are presented considering the recent developments at the European Commission and the results of the Clean Energy Technology Observatory. The sustainable development opportunities for PHS are discussed also considering the recent Horizon calls for projects launched by the European Commission and the ongoing discussions on water and energy storage needs, with focus on emerging technologies and strategies, e.g. sustainable refurbishment, digitalization, new electro-mechanical equipment and reservoir interconnection.

How to cite: Quaranta, E. and Pistocchi, A.: Water and energy storage in the European Union: current situation and future challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4728, https://doi.org/10.5194/egusphere-egu24-4728, 2024.

EGU24-6138 | ECS | Posters virtual | ERE2.4

An integrated GIS-based approach to support the implementation of Hybrid Pumped Hydro Storage in the abandoned Kardia open-pit lignite mine, Western Greece 

Pavlos Krassakis, Andreas Karavias, Evangelia Zygouri, Christos Roumpos, Georgios Louloudis, Konstantina Pyrgaki, Nikolaos Koukouzas, and Thomas Kempka

Energy supply security is currently a key priority for all European countries, and with a global push towards a decarbonized future, safe and reliable energy storage becomes vital. The European Union (EU) has introduced the European Green Deal, an initiative with the objective of achieving carbon neutrality by 2050, effectively reducing greenhouse gas (GHG) emissions to zero. As Europe shifts away from fossil fuels, renewable energy sources like solar, wind, and hydropower gain prominence. Hydropower, especially hybrid pumped hydropower storage (HPHS) of excess energy from the electric grid and renewable sources, can contribute to energy security. In this context, modern geospatial technologies can be utilized as promising tools at a preliminary phase by policymakers and stakeholders to support decision-making regarding the implementation of HPHS systems in terms of spatial development and design strategy. The Geographic Information System (GIS) approach can mitigate financial costs, environmental impacts, and exposure to potential hazards such as landslides, earthquakes, and floods. Additionally, advanced geospatial approaches can maximize energy storage by calculating the best-fit options according to the morphological properties of the landscape and the end-user requirements.

In the current work, selected criteria were defined and weighted based on topographic and proximity criteria, utilizing multi-criteria decision-making (MCDM), particularly the Analytical Hierarchy Process (AHP). Regarding the abandoned Greek Kardia open-pit lignite mine, seven regions were identified and recognized as suitable for HPHS, with potential energy storage capacities ranging from 1.09 to 5.16 GWh [1]. The preliminary suitability of different areas within the mine boundaries was categorized, ranging from very low to very high scoring, providing a better understanding of the existing landscape's potential for HPHS implementation. The utilized methodology identified specific locations with the highest potential for constructing the upper reservoir of the envisaged HPHS system, introducing an innovative tool that can be applied to open pit mines globally.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).

 

[1] Krassakis, P., Karavias, A., Zygouri, E., Roumpos, C., Louloudis, G., Pyrgaki, K., Koukouzas, N., Kempka, T., Karapanos, D. (2023): GIS-Based Assessment of Hybrid Pumped Hydro Storage as a Potential Solution 

How to cite: Krassakis, P., Karavias, A., Zygouri, E., Roumpos, C., Louloudis, G., Pyrgaki, K., Koukouzas, N., and Kempka, T.: An integrated GIS-based approach to support the implementation of Hybrid Pumped Hydro Storage in the abandoned Kardia open-pit lignite mine, Western Greece, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6138, https://doi.org/10.5194/egusphere-egu24-6138, 2024.

EGU24-6474 | ECS | Posters on site | ERE2.4

Transforming Coal Pits into Renewable Energy Sources: The Potential of Pumped Hydro Energy Storage in the Bełchatów Lignite Mine 

Mikołaj Ostraszewski, Jakub Jurasz, and Bartosz Kaźmierczak

The energy transition faces key challenges, including enhancing energy storage potential due to renewable energy sources' intermittency and repurposing abandoned coal mines. An approach that addresses both of these problems comprehensively is the concept of using mine pits and mine spoil heaps as sites for the location of Pumped Hydro Energy Storage (PHES). Poland, as one of European Union's member states and one of the most coal-dependent countries in Europe, is also obliged to fulfil postulates related to the transformation of electricity system. This work focuses on use of the Bełchatów Lignite Mine (KWB-B) for construction of PHES plant. It was assumed that the pits would take over a role of lower reservoir, while heaps could be used as upper reservoirs. This should be accomplished through appropriate earthworks, construction and prior analysis in terms of soil bearing capacity. In our work GIS tools have been used to determine key parameters of the PHES system, which are reservoir volumes, usable head and land slopes. The energy losses associated with required length of a penstock have been determined for each alternative. The Colebrook-White formula has been used to calculate a pressure height losses in the pipelines. In next step, another factor affecting reduction in energy efficiency has been determined, which is a loss of water from the upper reservoir through evaporation. The evaporation model has been created based on Penman-Monteith equation, which combines water evaporation related to aerodynamics and solar radiation. Finally, process of filling the reservoirs has been analysed, which under spontaneous groundwater filling conditions is estimated to take up to 60 years. For this reason, the concept presented in this study assumes additional reservoir recharge from the Warta River, around 29 kilometres away.  According to the results of the analysis done, in the most realistic scenarios, an energy storage potential is between 16.4 and 36.2 GWh per cycle, operating at around 75% efficiency, producing between 9.7 and 13.7 TWh of electricity per year, which is around 45% of the energy produced annually by the nearby Bełchatów lignite-fired power plant. The proposed concept enables 2,5-5,5-fold increase of the closed loop PHES storage capacity in Poland. With plans to phase out this lignite-fired power plant by 2036, development of a hybrid renewable energy source is a promising alternative that could be implemented in this area, especially if the filling of reservoirs would be accelerated through additional supply from nearby rivers.

How to cite: Ostraszewski, M., Jurasz, J., and Kaźmierczak, B.: Transforming Coal Pits into Renewable Energy Sources: The Potential of Pumped Hydro Energy Storage in the Bełchatów Lignite Mine, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6474, https://doi.org/10.5194/egusphere-egu24-6474, 2024.

EGU24-6875 | ECS | Posters virtual | ERE2.4

Numerical modeling of a multi-storey solar still in transient mode 

Chukwumaobi Kingsley Oluah, Howard.O. Njoku, and Valentine Ekechukwu

Climate change has intensified the scarcity of available drinking water, posing a critical challenge to communities, particularly in rural Africa. In response to this pressing issue, our study investigates the transient behavior of a multi-storey solar still as a sustainable solution. The research focuses on harnessing the latent heat of vaporization from the first stage to heat subsequent stages, utilizing pre-heated water from a reservoir. Mathematical models for each stage were developed, and the Numerical modeling of the system was carried out using the finite-forward discretization scheme on Scilab software. Insolation data for Nsukka (Lat = 6.8567, Lon= 7.3958) were extracted from NASA-SSC Database. Results showcase the temperature distribution and distillate output at each stage. The first stage reached an optimal temperature of 325K, while the second and third stages maintained averages of 322K and 319K, respectively. Distillate outputs for the first, second, and third stages were 7.5Kg, 5.7Kg, and 3.8Kg, respectively. An overall still efficiency of 16% was achieved, hence the multi-story solar still presents a promising avenue to address the water scarcity challenges faced by vulnerable rural communities in Africa.

How to cite: Oluah, C. K., Njoku, H. O., and Ekechukwu, V.: Numerical modeling of a multi-storey solar still in transient mode, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6875, https://doi.org/10.5194/egusphere-egu24-6875, 2024.

EGU24-8940 | ECS | Posters on site | ERE2.4

Mapping the perceived potential of energy harvesters to increase the resilience of European water and energy infrastructure  

Ivana Stepanovic, Steven Frigerio, Bjarnhéðinn Guðlaugsson, and David Finger

Energy harvesters (EH) are devices designed to capture and convert mechanical energy from ambient sources, which can be converted into electrical energy employing piezoelectric materials. Energy harvesters can capture and convert energy from vortex-induced vibrations in water flows such as water piping, open channels, and natural streams. Harvested energy can be used or stored to power small electronic components such as wireless sensors. These renewable and environmentally friendly energy sources present a tremendous opportunity for clean, reliable off-grid energy production. In the EU–funded project H-HOPE (https://h-hope.eu/), energy harvesters are being designed and deployed for various environments to improve and enhance water and energy resilience. In Reykjavik, Iceland, EH can be implemented in geothermal pipes, providing energy for a sensor network in volcanically active areas where traditional powered sources may be unavailable. In Izmir, Turkey, EH can be implemented in the water supply systems, offering reliable electricity for monitoring drinking water quality. In Padova, Italy, EH can be installed in sewage systems, providing electricity for continuous water quality monitoring. In natural streams like fjords (West Fjords, Iceland) and lagoons (Venice, Italy), EH might be upscaled to power remote communities. However, the perceived potential for EH by local energy stakeholders is unknown. To address this, we conducted semi-structured interviews and expert surveys with relevant stakeholder groups to assess the perceived opportunities and challenges of implementing EH in the mentioned case studies. Preliminary results are visualized in causal diagrams, identifying positive and negative feedback loops of stakeholder perceptions. This analysis identifies both enablers and barriers to EH implementation. These findings will be used to develop a strategy for energy and water service providers to enhance the resilience of existing water and energy infrastructure across Europe and assess the potential uptake and validation of such technology by stakeholders.

How to cite: Stepanovic, I., Frigerio, S., Guðlaugsson, B., and Finger, D.: Mapping the perceived potential of energy harvesters to increase the resilience of European water and energy infrastructure , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8940, https://doi.org/10.5194/egusphere-egu24-8940, 2024.

EGU24-10643 | Posters on site | ERE2.4

Economics of hybrid pumped hydropower storage in open-pit coal mines: a case study for the Greek energy market 

Christopher Otto, Priscilla Ernst, Christos Roumpos, Georgios Louloudis, Eleni Mertiri, and Thomas Kempka

A dynamic techno-economic simulation model was developed in the present study to assess the capital and operational expenditures (CAPEX and OPEX) as well as economic benefits of a prospective Hybrid Pumped Hydropower Storage (HPHS) installation to be realised in a Greek open-pit coal mine. HPHS is not only limited to store excess energy produced by local renewable energy sources, i.e. photovoltaic and wind farms, but can also be applied to store of excess energy from the grid. The model accounts for losses incurring while charging the upper reservoir with water when excess energy from renewables and the electric grid is available as well as discharging the upper reservoir for electricity generation when the national electricity demand exceeds the energy provided by the grid. A charging and discharging scheme for the HPHS installation was dynamically calibrated by means of historic energy market data, including time-dependent national energy balances and electric grid costs. Revenues, expenditures and profits of the prospective HPHS implementation were calculated, and the key economic parameters Net Present Value (NPV), Internal Rate of Return (IRR) and Discount Payback Period (DPP) determined to account for the overall system profitability during its’ entire operational time. The model’s technical implementation and applicability for system performance optimisation are discussed in detail, especially in view of a profit-maximising energy storage scheme, which was developed and applied to stochastic grid cost development predictions to account for the HPHS installation’s potential future benefits. The model can be integrated with online real-time data to economically schedule HPHS operation in highly dynamic energy systems.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).

How to cite: Otto, C., Ernst, P., Roumpos, C., Louloudis, G., Mertiri, E., and Kempka, T.: Economics of hybrid pumped hydropower storage in open-pit coal mines: a case study for the Greek energy market, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10643, https://doi.org/10.5194/egusphere-egu24-10643, 2024.

The energy transition from fossil fuels to clean energy is inevitable to limit climate change. Pumped storage hydropower can compensate for the balancing of load, provides various ancillary services, and integrates variable renewable energy in the grid. However, uncertainties such as market structure, long-term natural gas prices, variable renewable energy penetration, government incentives, and regulatory policy, making it difficult to develop a viable business case for new pumped storage hydropower project. This research article considers improving financial viability of new pumped storage hydropower project by reducing upfront capital cost by utilizing existing conventional hydropower resources and reducing pumping/charging costs by finding a potential site where a water stream reaches the upper reservoir directly. The fast-track, cost-effective, and environmentally friendly approach investigates the true potential of this configuration for the case study of 200 MW Paras pumped storage hydropower with integrated 300 MW Balakot conventional hydropower. The article considers numerous scenarios for both closed-loop and open-loop pumped storage hydropower and calculates the levelized cost of energy storage for all scenarios. The conclusion is that utilizing existing conventional hydropower resources and considering water stream entering directly into the upper reservoir decreases the overall levelized cost of energy storage from 13.73 to 11.77 US$ cents/kWh (14% decrease). Results of the levelized cost of energy storage can help experts, regulators, power producers, and investors realize the importance of pumped storage hydropower as a reliable, cost-effective, and sustainable energy storage technology to integrate variable renewable energy.

How to cite: Jehanzeb, N. and Ali, M.: Strategy to improve financial viability of pumped storage hydropower: Techno-economic analysis of pumped storage hydropower with existing conventional hydropower, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14403, https://doi.org/10.5194/egusphere-egu24-14403, 2024.

EGU24-14604 | ECS | Orals | ERE2.4 | Highlight

Energy transition modelling for Arctic off-grid communities 

Magnus de Witt

Fossil fuels are the most common energy source for electricity generation among remote Arctic communities. Around 80% of remote Arctic communities are predominantly dependent on fossil fuels. Even if some of the region's raw oil is extracted, the processed diesel must be imported. Transport is complicated and strongly dependent on weather conditions. The harsh Arctic weather conditions make fuel transportation is complex, risky, and costly, leading to an insecure primary energy supply and high fuel prices. For many inhabitants of remote Arctic communities, the high energy costs are a significant cost burden because unemployment, temporary jobs, and a resulting low income are common issues.

This presentation will focus on implementation strategies for renewable energy sources into the energy mix or remote Arctic communities, with the aim of lowering the energy cost burden. System dynamics (SD) was used as a methodology to analyze the implementation process. SD is a powerful tool to analyse complex systems with non-linear relationships, as it is expected to find them among the policy strategies for energy transition. Investing in renewable energy technology is a high-risk investment; therefore, the effects of such an investment must be well studied to gain an optimal result. Furthermore, remote communities are often facing financial issues, which limits investments in energy infrastructure. Therefore, the model is looking for affordable ways of investing in energy infrastructure. The model aims for a sustainable performance of the utility provider, whereas the electricity cost for the consumer can be lowered and the utility provider can perform well on a non-profit base.

The research indicates that renewables have a significant cost-saving potential. Despite all the positive effects, investment in renewables can be risky and a substantial commitment for small communities. Moreover, depending on the type of renewable energy source, there can be some environmental impact that must be considered as well. With a well-structured integration process, the most can be made out of the investment, which helps lower the energy cost burden even more.

How to cite: de Witt, M.: Energy transition modelling for Arctic off-grid communities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14604, https://doi.org/10.5194/egusphere-egu24-14604, 2024.

EGU24-14751 | Posters on site | ERE2.4 | Highlight

An interdisciplinary feasibility study on hybrid pumped hydropower storage of excess energy in open-pit coal mines 

Thomas Kempka, Priscilla Ernst, Krzysztof Kapusta, Nikolaos Koukouzas, Jaroslaw Darmosz, Christos Roumpos, and Tomas Fernandez-Steeger and the ATLANTIS project partners

Scheduled decommissioning of lignite mining in Europe requires innovative and economic strategies to support coal regions in transition. The R&D project ATLANTIS is funded by the European Research Fund for Coal and Steel and started in late 2021, aiming at an integrated feasibility assessment on transforming open-pit coal mines into hybrid energy storage projects. Hereby, repurposing of open-pit mines for hybrid pumped hydropower storage (HPHS) of excess energy from the electric grid and renewable sources available in the vicinity of open-pit mines in abandonment will contribute to the EU Green Deal, while increasing the economic value,

stabilising the regional job market and contributing to EU energy supply security. The main objective of ATLANTIS is the elaboration of a technical and economic feasibility study on HPHS in open-pit coal mines. The present contribution will provide insights into the R&D activities within the scope of the project. For that purpose, two target open-pit mines in Greece and Poland were investigated in detail, including analyses supported by geographic information systems (GIS) based on previously defined HPHS design criteria [1] as well as hydro(geo)logical, hydrochemical and geotechnical analyses. At the Polish Szczercow mine located in the Lodz Coal Basin a HPHS capacity of 350 MW can be realised with a hydraulic head difference of approximately 240 m, able to support even more than the currently planned build-out of about 250 MW renewable energy sources made up of wind and photovoltaic parks. A total capacity of 180 MW is feasible at the Kardia mine in the Ptolemais Basin in Greece, whereby the hydraulic head difference amounts to about 100 m. Here, a photovoltaic build-out of 1.2 GW is scheduled. Potential environmental impacts were addressed via an extended risk analysis, consisting of qualitative and quantitative and components integrated by means of feedback loops and supported by the experience of multidisciplinary experts in the fields of hydrogeology, hydrogeochemistry, geotechnics, mining engineering and socio-economics. Based on the findings of this assessment, mitigation measures for the high-ranked risks were defined and are already considered in the course of the specific mine abandonment processes. Dynamic economic models using day-ahead energy market data were implemented to optimise the HPHS operation and support decision making related to the operational modes. Furthermore, the results of the socio-economic footprint assessment undertaken highlight the regional benefits of the HPHS implementation as alternative to the previously envisaged restoration procedure. The elaborated feasibility study on HPHS in abandoned open-pit mines is a key contribution to the industrial partner’s decision making processes and further demonstrates the potentials for application of the project’s findings at the EU level.

 

[1] Krassakis, P., Karavias, A., Zygouri, E., Roumpos, C., Louloudis, G., Pyrgaki, K., Koukouzas, N., Kempka, T., Karapanos, D. (2023): GIS-Based Assessment of Hybrid Pumped Hydro Storage as a Potential Solution for the Clean Energy Transition: The Case of the Kardia Lignite Mine, Western Greece. Sensors, 23, 2, 593. https://doi.org/10.3390/s23020593

 

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).

How to cite: Kempka, T., Ernst, P., Kapusta, K., Koukouzas, N., Darmosz, J., Roumpos, C., and Fernandez-Steeger, T. and the ATLANTIS project partners: An interdisciplinary feasibility study on hybrid pumped hydropower storage of excess energy in open-pit coal mines, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14751, https://doi.org/10.5194/egusphere-egu24-14751, 2024.

EGU24-15312 | Orals | ERE2.4 | Highlight

Renewable Electric Energy Storage Systems by Storage Spheres on the Seabed of Deep Lakes or Oceans 

Horst Schmidt-Boecking, Gerhard Luther, and Michael Düren

A new underwater pumped storage hydropower concept (U.PSH) is described that can store electric energy by using the high water pressure on the seabed or in deep lakes to accomplish the energy transition from fossil to renewable sources. Conventional PSH basically consists of two storage reservoirs (upper and lower lake) at different topographical heights. It needs special topographic conditions, which are only limitedly available in mountain regions. Furthermore, due to the lack of acceptance and the environmental impact, new conventional PSH projects are very unlikely to be built in larger numbers in Europe in the near future. The presented solution solves these issues by placing the storage system on the seabed, thus having other geographical requirements. It operates as follows: in contrast to well-known conventional PSH plants, which use two separated water reservoirs of different heights, the U.PSH concept uses the static pressure of the water column in deep waters by installing a hollow concrete sphere in deep water. Storage of electricity is achieved by using a reversible pump in the hollow sphere. Upon opening a valve, water flows into the sphere, driving a turbine/generator, thereby discharging the storage device. In order to re-charge, the water is pumped out of the sphere against the pressure of the surrounding water. The power and energy, respectively, are proportional to the surrounding water pressure at the seabed. The amount of energy stored depends on the water depth and the volume of the spheres. The spheres need a cable connection to the shore or to a close-by floating transformer station (e.g., an offshore wind plant). No other connections such as pipes are needed. The functional principle of this energy storage technology, its state of the art, its storage capacity and the shape and size of the required spheres are discussed in this paper.

 

How to cite: Schmidt-Boecking, H., Luther, G., and Düren, M.: Renewable Electric Energy Storage Systems by Storage Spheres on the Seabed of Deep Lakes or Oceans, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15312, https://doi.org/10.5194/egusphere-egu24-15312, 2024.

EGU24-15490 | ECS | Posters on site | ERE2.4 | Highlight

REFLOW: An Open-Source Workflow for Renewable Energy Potentials 

Tristan Pelser, Maximilian Hoffmann, Jann Michael Weinand, Patrick Kuckertz, and Detlef Stolten

The evaluation of renewable energy potentials is growing in importance across multiple sectors, including in energy planning, industry, research, and policymaking. Despite the abundance of research into regional-scale wind and solar potentials, the lack of reproducibility and transparent workflows consistently challenges validity. Typically, various steps in renewable energy potential assessments are conducted separately, often employing various software tools. For example, data processing may be conducted in a python environment, whereas land eligibility analysis utilizes Geographic Information System (GIS) software, and wind or solar simulations rely on specialized power simulation software. This fragmentation, as well as a general trend of not making data and code openly available, impedes efficiency, and hampers scientific reproducibility and transparency. Our research introduces a novel, Python-based open-source workflow to address this issue, which employs a pipeline management module (Luigi) for handling tasks and dependencies, and Docker to facilitate deployment. The Renewable Energy workFLOW (REFLOW) encompasses the entire process of potential assessments, from data acquisition to result validation, including critical steps like land eligibility assessment, explicit turbine placement, and wind or solar simulation. The workflow’s modular nature allows for integration of various software modules and methodologies, enhancing its adaptability to various scenarios. REFLOW can be executed in multiple operating systems and requires no significant programming knowledge. We demonstrate REFLOW’s capabilities for a wind power potential assessment of the North Sea region, conducting ocean eligibility exclusions, explicit turbine placings, and a simulation of wind power generation for a period of ten years, using data from the ERA-5 reanalysis and Global Wind Atlas. The entire workflow is fully reproducible, including all data acquisition and processing steps. Thus, REFLOW constitutes a significant step towards versatile yet reproducible renewable potential analyses.

How to cite: Pelser, T., Hoffmann, M., Weinand, J. M., Kuckertz, P., and Stolten, D.: REFLOW: An Open-Source Workflow for Renewable Energy Potentials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15490, https://doi.org/10.5194/egusphere-egu24-15490, 2024.

Decommissioning of lignite mines in the course of phasing-out electric power generation from fossil fuels in the European Union (EU) is one of the strategic key pillars to reduce net greenhouse gas emissions by 55% compared to the 1990 levels until 2030, and achieving climate-neutrality by 2050. Germany’s emission reduction targets are even more ambitious with 65% and 88% scheduled for 2030 and 2040, respectively.

Repurposing phasing-out open-pit lignite mines into Hybrid Pumped Hydropower Storage (HPHS) installations for excess energy from the electric grid and renewable sources contributes not only to the EU Green Deal and EU energy supply security, but additionally increases the regional economic value and stabilises the job market. Pumped hydropower is well established for storing excess energy from the electric grid and for load balancing with a total installed capacity of 7.89 GW in Germany and a current total share of 78.6% in the energy storage sector. Total round-trip efficiencies of up to 85% and extraordinary high storage capacities compared to battery-based solutions can be realised. Another advantage of implementing the technology in former open-pit mines is that costs of constructing the two required storage reservoirs are significantly reduced due to the presence of the open-pit hole. Multiple open-pit lignite mines were closed in Germany in the past decades, and nine are expected to cease operation by 2038.

Several studies assessing the potentials for PHS based on existing reservoirs have been undertaken, but these do not yet consider the additional potentials of open-pit mines. The aim of the present study was to investigate the potential theoretical and technical power production and storage capacities becoming available by repurposing open-pit mines into HPHS installations. For that purpose, a database of German open-pit lignite mines was established. An analytical model was employed to determine the power production and storage capacities of 34 German open-pit lignite mines, of which 13 meet the previously defined site selection criteria. The results of the present study show that the currently installed energy storage potentials in Germany can be extended by additional 1.42 GW (increase by >18%), increasing the installed PHS capacity by 22.9% at the same time. These findings are essential to guide policy and decision makers involved in the German and EU energy transition. The methodology will be extended to member states of the European Union in the next step.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS).

How to cite: Ernst, P. and Kempka, T.: Pumped hydropower storage in open-pit mines can provide substantial contributions to the EU energy transition – a case study for Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16405, https://doi.org/10.5194/egusphere-egu24-16405, 2024.

EGU24-17781 | ECS | Posters on site | ERE2.4

Stability of abandoned pit slopes - how groundwater and lake water control may support safety while flooding 

Ershad Ud Dowlah Pahlowan, Anika Braun, and Tomas Manuel Fernandez-Steeger

In Europe's move towards decarbonization, renewable energy emerges as a key player, with its swift expansion crucial for cutting carbon emissions. Addressing the modern energy scenario, an innovative energy storage solution: transforming abandoned open-pit mines into large-scale facilities using pumped-hydro power storage (PHS) technology. This system operates by elevating water during periods of low demand and releasing it to produce electricity when demand peaks, mirroring the function of traditional hydropower plants.

 

A significant hurdle in this transformation is the initial flooding of the mine pit to form the lower reservoir of the PHS system. This phase is marked by complex geotechnical challenges, especially in terms of mine slope stability, influenced by the difference in water head between the groundwater and the reservoir. A key aspect is to ensure an effective hydraulic head, particularly when the upper reservoir is positioned in areas with minimal head difference from the lower reservoir. Our approach revolves around managing the head difference between lake water and groundwater effectively, safeguarding mine slope stability for PHS operations. To achieve this, we compare two different approaches to maintaining the head difference between lake water and groundwater and assess the slope stability for different stages of flooding using the Limit Equilibrium Method (LEM). These approaches are aimed at refining the hydraulic head difference, thereby maximizing the energy generation capacity and promoting efficient, sustainable energy solutions, while ensuring safe operation in terms of slope stability.

How to cite: Pahlowan, E. U. D., Braun, A., and Fernandez-Steeger, T. M.: Stability of abandoned pit slopes - how groundwater and lake water control may support safety while flooding, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17781, https://doi.org/10.5194/egusphere-egu24-17781, 2024.

EGU24-18817 | Posters on site | ERE2.4

Analysis of socio-economic footprint for hybrid pumped hydropower storage of excess energy in open-pit coal mines 

Mariusz Kruczek, Krzysztof Kapusta, Thomas Kempka, Priscilla Ernst, Nikolaos Koukouzas, Jaroslaw Darmosz, Christos Roumpos, and Tomas Fernandez-Steeger and the and the ATLANTIS project partners

The transformation of coal regions into sustainable energy landscapes is a strategic aspect of the European Union's initiatives. This article is dedicated to the socio-economic impact of establishing hybrid pumped hydro storage (HPHS) systems in transitioning open-pit coal mines. The solutions analyzed are part of the ATLANTIS project, which aims to utilize the unique regional benefits these areas offer for HPHS implementation.

These coal regions, currently undergoing transformation, present distinct advantages for HPHS system deployment. Their existing infrastructure, coupled with the potential for integration with renewable energy sources, makes them ideal sites for sustainable energy projects. The ATLANTIS project enables the identification and assessment of these attributes to maximize both economic and socio-economic benefits, enhancing the value of these regions beyond their traditional mining roles.

A crucial element of this research is the quantification of the enhanced socio-economic footprint resulting from the HPHS system implementation. This includes a detailed analysis of how repurposing former coal mines into energy storage facilities can lead to broader economic revitalization and socio-economic development. The study examines the potential for job creation, stimulation of local economies, and overall improvement in community well-being.

By utilizing a comprehensive approach that incorporates regional economic, demographic, and market data, this article offers a holistic view of the socio-economic benefits of HPHS systems. It aims to provide valuable insights to policymakers, energy sector stakeholders, and affected communities, underscoring the potential of repurposed mining landscapes in the transition towards a more sustainable energy future.

The present study has received funding from the Research Fund for Coal and Steel—2020, under grant agreement No. 101034022 (ATLANTIS). 

How to cite: Kruczek, M., Kapusta, K., Kempka, T., Ernst, P., Koukouzas, N., Darmosz, J., Roumpos, C., and Fernandez-Steeger, T. and the and the ATLANTIS project partners: Analysis of socio-economic footprint for hybrid pumped hydropower storage of excess energy in open-pit coal mines, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18817, https://doi.org/10.5194/egusphere-egu24-18817, 2024.

EGU24-18880 | Orals | ERE2.4

Variability in solar based power generation at the Eastern Mediterranean 

Nikolaos Papadimitriou, Ilias Fountoulakis, John Kapsomenakis, Antonis Gkikas, Stelios Kazadzis, Christos Spyrou, Kyriakoula Papachristopoulou, and Christos S. Zerefos

The utilization of solar photovoltaic (PV) systems is pivotal towards reducing carbon dioxide emissions within the global energy infrastructure. Climate change is expected to affect atmospheric parameters such as cloudiness and aerosol, which are key drivers for the amount of solar radiation reaching the ground thus modifying solar-based power generation.

In this study, we investigate the spatial and the temporal variability of PV plant energy output at the Eastern Mediterranean during the period 1950-2100, with respect to the corresponding changes of the shortwave downwelling solar radiation, aerosols, cloudiness, and near-surface air temperature, which are crucial for estimating the solar energy production. The trends of the aforementioned variables, obtained from the analysis of gridded data retrieved from climate model projections, particularly from the “Region 4: Europe (EURO)” domain of the Coordinate Regional Downscaling Experiment (CORDEX). Aiming to achieve an optimal approximation of the changes in aerosol concentrations, we employed the CNRM-ALADIN63 Regional Climate Model (RCM) which interactively considers them. The boundary conditions are derived from projections of the CNRM-CERFACS-CM5 Global Climate Model (GCM) within the 5th phase of the Climate Model Intercomparison Project (CMIP5), encompassing the historical period (1951-2005) and future scenarios (2006-2100) under Representative Concentration Pathways (RCP) 2.6, 4.5, and 8.5. For the determination of the PV energy output, we performed numerical simulations with the Global Solar Energy Estimator (GSEE), considering as input values the downwelling solar radiation, air temperature, as well as the tilt, capacity, and orientation of the hypothetical solar panels. Data from the Copernicus Atmosphere Monitoring Service (CAMS) and Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) datasets are also used for the intercomparison of the modelled downwelling solar radiation. Our results are in line with the findings of previous studies that assessed such changes capable of causing surplus or deficit in relation to solar energy production. Furthermore, we show that changes can vary significantly on a regional level.

Nikolaos Papadimitriou would like to acknowledge funding for the participation at EMS2023 from the COST Action HARMONIA (International network for harmonization of atmospheric aerosol retrievals from ground based photometers), CA21119. The work has been also supported by the action titled “Support for upgrading the operation of the National Network for Climate Change (CLIMPACT II)”, funded by the Public Investment Program of Greece, General Secretary of Research and Technology/Ministry of Development and Investments.

How to cite: Papadimitriou, N., Fountoulakis, I., Kapsomenakis, J., Gkikas, A., Kazadzis, S., Spyrou, C., Papachristopoulou, K., and Zerefos, C. S.: Variability in solar based power generation at the Eastern Mediterranean, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18880, https://doi.org/10.5194/egusphere-egu24-18880, 2024.

EGU24-19151 | Posters on site | ERE2.4

Mapping the service areas of Great Britain's electrical infrastructure for whole systems energy decarbonisation 

Joseph Day, Grant Wilson, and Daniel Donaldson

Electrification of presently fossil fuel-based heating and transport is recognised as a likely pathway to a net-zero energy system. However, this vector shifting will involve a significantly increased demand on the electrical network. Therefore, it is important to understand the geography of the electrical network in order to accurately anticipate where these extra demands will occur and their impact on peak demand, to in turn determine if network reinforcement or other flexibility solutions would be required.

The area served by the same piece of electrical infrastructure, such as a medium voltage substation (also known as a primary) can be visualised by a polygon drawn around all the properties which are normally connected to that substation. This is a valuable addition to the energy data landscape which can enable analysis of local area-based decarbonisation scenarios. For the first time, our research group has compiled the shapefiles from the six separate regional Distribution Network Operator companies in Great Britain, into a single map and made the data available for public download on Zenodo (it has been downloaded over 150 times as of January 2024)[1].  The methods of deriving these boundaries also differ by region (most use a Voronoi polygon algorithm), so they are critically contrasted.

The main benefit of opening this data is to allow the open modelling community and other stakeholders to conduct their own analysis and develop use cases with a geographical unit (the primary substation) which is relevant to the energy network, rather than an administrative or political boundary for which lots of energy datasets are currently aggregated to. In one example of these use cases, we have used open government data on annual domestic energy consumption to determine the mean domestic gas consumption for each of the 4436 primary substations in Great Britain, and place them in a decile. This gives insight into the scale of energy required to be provided through that part of the electrical network rather than the gas network, should heat be electrified to varying degrees. As a fundamental dataset and combined with network monitoring data, our output could ultimately enable advanced models such as digital twins, with applications for near and long-term energy forecasting could be used for system planning.


[1] https://zenodo.org/records/8335354

How to cite: Day, J., Wilson, G., and Donaldson, D.: Mapping the service areas of Great Britain's electrical infrastructure for whole systems energy decarbonisation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19151, https://doi.org/10.5194/egusphere-egu24-19151, 2024.

EGU24-19423 | Orals | ERE2.4 | Highlight

Increasing the grid flexibility with unconventional operations in one of the largest Pumped Storage Units in EU: The tests of XFLEX Hydro in Frades II 

Alexandre Presas, David Valentin, Pedro Diogo, Alexander Jung, Greco Moraga, Monica Egusquiza, and Eduard Egusquiza

Pumped Storage Hydro (PSH) serves as a significant contributor to the transition toward net zero emissions, primarily due to its capacity to store large amounts of energy with very high round trip efficiency (RTE). This is especially important given the volatility and unpredictability associated with the current energy mix, largely influenced by sources like wind and solar. Managing these fluctuations poses operational challenges for pumped storage schemes.

 Within the EU's XFLEX Hydro project, various developments and operational strategies have been tested in one of the largest Pumped Storage Units globally, aiming to enhance actual Pumped Storage flexibility services. This paper provides an overview of the effects of some of the most demanding operations, such as fast ramps, variations in power as pumps, and hydraulic short-circuit operations in the hydraulic and mechanical components of the Pumped Storage Plant.

How to cite: Presas, A., Valentin, D., Diogo, P., Jung, A., Moraga, G., Egusquiza, M., and Egusquiza, E.: Increasing the grid flexibility with unconventional operations in one of the largest Pumped Storage Units in EU: The tests of XFLEX Hydro in Frades II, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19423, https://doi.org/10.5194/egusphere-egu24-19423, 2024.

EGU24-20832 | ECS | Orals | ERE2.4 | Highlight

Electric Heat Revolution: Navigating the Landscape of the Future Electricity Market 

Lavin (Zahra) Jafaripour and Andrew Lyden

As the global movement towards energy system decarbonisation gains traction, electrifying heating systems will emerge as a pivotal approach to reduce carbon emissions in the residential sector. Electrification promises a substantial reduction in greenhouse gas emissions, improved energy efficiency, and enhanced integration of renewable energy sources. Furthermore, electrified heating systems offer flexibility through demand response mechanisms, contributing to grid stability and resilience.

The challenges of electrifying heating systems are multifaceted, encompassing technical, economic, and societal dimensions. Technical challenges include addressing the intermittency of renewable energy sources, upgrading existing infrastructure, and ensuring grid reliability. Economic challenges involve the costs associated with technology adoption, potential impacts on energy bills, and financial considerations for both consumers and utilities. Societal challenges entail managing the transition for workers in traditional heating industries, addressing potential energy poverty concerns, and fostering public acceptance. Alongside these challenges, the transition to electrified heating has the potential to substantially influence the optimal design of the electricity market. The increased demand for electricity, particularly during peak heating periods, necessitates strategic modifications to market structure and operational frameworks. While there are numerous advantages and improvements associated with this transition, a comprehensive understanding of the impacts of the electrification of heating within the electricity market is currently lacking.

The main goal of this paper is to assess the advantages and challenges associated with electrifying heating systems, and potential changes that will take place in the electricity market as a consequence of this electrification. Through an extensive literature review, this paper seeks to contribute valuable insights for the development of strategies and policies aimed at fostering a sustainable and resilient electricity market, particularly in the evolving landscape of heating technologies.This study lays the groundwork for additional investigation into the complex relationship between heating electrification and the changing electricity market, providing important information for sustainable energy transitions.

 

How to cite: Jafaripour, L. (. and Lyden, A.: Electric Heat Revolution: Navigating the Landscape of the Future Electricity Market, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20832, https://doi.org/10.5194/egusphere-egu24-20832, 2024.

EGU24-22348 | Posters on site | ERE2.4

A Digital Twin for Energy Consumption Prediction and Thermal Comfort Monitoring in Residential Buildings 

Fateme Dinmohammadi and Mahmood Shafiee

The residential buildings are responsible for approximately one-quarter of the world’s energy consumption and they play an important role in mitigating global climate change [1]. To improve energy efficiency and reduce carbon emissions in the residential building sector, it is necessary to predict the energy consumption and thermal comfort under urban climate change. Nowadays, a large number of IoT sensors, smart devices, and controllers are employed in residential buildings to collect data in a real time and seamless way [2]. Emerging digital technologies such as digital twins and artificial intelligence (AI) have proven to be a powerful tool to provide dynamic, reliable, robust, and agile models for predicting and monitoring the energy consumption and air pollutant emission levels in industrial sectors. However, digital twins have received very little attention in the residential building sector [3]. The main aim of this study is to design and prototype a digital twin system for thermal comfort monitoring, visualization, tracking, energy management, prediction, and optimization in residential buildings under different indoor and outdoor conditions. Our digital twin model is built on the basis of a thermodynamic model incorporating building attributes such as heating methods, wall materials, etc. with real-time sensor and IoT information updates to deliver precise predictive foresight and also determine the different indoor and outdoor factors contributing the most to residential heating energy consumption and thermal comfort. The digital twin model will be tested on a dataset containing sensor data, building attribute features, and weather records during five heating seasons of residential buildings in a city in Russia that was published for the first time in 2020 by IEEE DataPort [4].

References

[1] United Nations Environment Programme (2020), The 2020 global status report for building and construction: Towards a zero-emission, efficient and resilient buildings and construction sector. https://globalabc.org/sites/default/files/inline-files/2020%20Buildings%20GSR_FULL%20REPORT.pdf.

[2] Dinmohammadi, F., Wilson, D. Understanding the End-Users and Technical Requirements for Real-Time Streaming Data Analytics and Visualisation, In: 26th International Conference on Automation and Computing (ICAC), 02-04 September 2021, Portsmouth, UK.

[3] Dinmohammadi, F., Han, Y., Shafiee, M. Predicting Energy Consumption in Residential Buildings Using Advanced Machine Learning Algorithms, Energies 16 (9), 3748.

[4] Zorin, P.; Stukach, O. Data of Heating Meters from Residential Buildings in Tomsk (Russia) for Statistical Modeling of Thermal Characteristics of Buildings. Published on 5 October 2020. Available online: https://ieee-dataport.org/documents/data-heating-meters-residential-buildings-tomsk-russia-statistical-modeling-thermal.

How to cite: Dinmohammadi, F. and Shafiee, M.: A Digital Twin for Energy Consumption Prediction and Thermal Comfort Monitoring in Residential Buildings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22348, https://doi.org/10.5194/egusphere-egu24-22348, 2024.

EGU24-523 | ECS | Orals | ERE2.5

Downscaling CMIP6 climate projections to classify the future offshore wind energy resource and calculate the Levelized Cost of Energy of various wind farm designs in the Spanish territorial waters. 

Brieuc Thomas, Xurxo Costoya, Maite deCastro, Damián Insua-Costa, Martín Senande-Rivera, and Moncho Gómez-Gesteira

Spain has taken a significant stride towards its goal of installing 1 to 3 GW of floating offshore wind capacity by 2030. This was achieved through the implementation of a Maritime Spatial Planning (MSP) covering 19 designated areas, where it is expected the installation of offshore wind farms in the upcoming years. Therefore, it is of interest analysing the impact of climate change on offshore wind resource in these areas. To achieve a sufficiently high spatial resolution for this study, a dynamic downscaling of a multi-model ensemble from the 6th phase of the Coupled Model Intercomparison Project (CMIP6) was conducted using the Weather Research and Forecasting (WRF) model in the Spanish territorial waters, encompassing the Iberian Peninsula, Balearic Islands, and Canary Islands. Thus, wind data were obtained from the latest climate projections, with a 10-km spatial resolution and a 6-hour temporal resolution. The results were compared, for a historical period from 1985 to 2014, with data from the ERA5 reanalysis database and with observational data from buoys. The results of this validation process showed a great accuracy in the dynamical downscaling performed, generally better than when using data from the Coordinated Regional Climate Downscaling Experiment (CORDEX), which performed dynamical downscaling on data from several CMIP5 climate models. Future projections, from 2015 to 2100, were assessed under the Shared Socioeconomic Pathways (SSP) 2-4.5 and 5-8.5 scenarios. The findings of this study indicate a projected growth in Spain's offshore wind energy potential, especially in the Atlantic Ocean and around the Canary Islands.

Using wind speed data from simulations carried out with the WRF atmospheric model, the offshore wind energy resource was classified in the 19 areas involved in de Spanish MSP. This classification considered the wind power density but also factors such as resource stability, environmental risks, and installation costs. The results reveal significant diversity in wind resource classification within potential offshore wind farm areas, ranging from "fair" (3/7) to "outstanding" (6/7). The most promising areas for offshore wind farm development in the future are situated in the northwest of the Iberian Peninsula and the Canary Islands.

The identification of the most cost-effective solutions in each area involves determining the optimal combination of rated power and the number of turbines and comparing them across different locations to pinpoint the most economical sites for offshore wind energy exploitation. This economic analysis was done for a 25-year near-future period under the SSP 2-4.5 scenario, aligning with the expected operational lifespan of wind farms. This study includes the calculation of the Levelized Cost of Energy (LCOE) index, which gives an indication of the minimal price at which the electricity should be sold in order for the project to be profitable. The results highlight that the LCOE is lower for farms with a higher number of wind turbines featuring increased rated power. While the Canary Islands exhibit the most economically advantageous prices overall, other regions such as Galicia and Cataluña also boast promising areas.

How to cite: Thomas, B., Costoya, X., deCastro, M., Insua-Costa, D., Senande-Rivera, M., and Gómez-Gesteira, M.: Downscaling CMIP6 climate projections to classify the future offshore wind energy resource and calculate the Levelized Cost of Energy of various wind farm designs in the Spanish territorial waters., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-523, https://doi.org/10.5194/egusphere-egu24-523, 2024.

EGU24-1851 | ECS | Orals | ERE2.5

Impacts of extreme land-use change on wind profiles and wind energy according to regional climate models   

Jan Wohland, Peter Hoffmann, Daniela C.A. Lima, Marcus Breil, Olivier Asselin, and Diana Rechid

Humans change the climate in many ways, for example, by emitting greenhouse gases or by changing land-use. While studies typically investigate the joint effects of human activity, we here isolate the impact of afforestation and deforestation on winds in the lowermost 350 m of the atmosphere to better understand the role of forests in large-scale wind energy assessments. We use vertically resolved sub-daily output from two regional climate models and compare two extreme scenarios from the LUCAS simulations (Davin et al., 2020). Our results show that afforestation lowers wind speeds by more than 1 m/s in many locations across Europe even 300 m above ground and thus matters at wind turbine hub heights. While adapting the parameters in standard extrapolation allows to capture long-term mean winds well, it remains insufficient to compute wind energy potentials as it fails to capture essential spatio-temporal details, such as changes in the daily cycle. We therefore follow an alternative approach that leverages the vertical resolution of the regional climate models to account for wind profile complexity. Doing so, we report strong changes in wind energy capacity factors due to afforestation and deforestation: they change by up to 50 % in relative terms. Our results confirm earlier studies that land use change impacts on wind energy can be severe and that they are generally misrepresented with common extrapolation techniques.

 

References:

Davin, E. L., Rechid, D., Breil, M., Cardoso, R. M., Coppola, E., Hoffmann, P., Jach, L. L., Katragkou, E., de Noblet-Ducoudré, N., Radtke, K., Raffa, M., Soares, P. M. M., Sofiadis, G., Strada, S., Strandberg, G., Tölle, M. H., Warrach-Sagi, K., and Wulfmeyer, V: Biogeophysical impacts of forestation in Europe: First results from the LUCAS Regional Climate Model intercomparison, Earth Syst. Dynam., 11, 183–200, 2020, https://doi.org/10.5194/esd-11-183-2020, 2020

Preprint:

Wohland, J., Hoffmann, P., Lima, D. C. A., Breil, M., Asselin, O., and Rechid, D.: Extrapolation is not enough: Impacts of extreme land-use change on wind profiles and wind energy according to regional climate models, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-2533, 2023

How to cite: Wohland, J., Hoffmann, P., Lima, D. C. A., Breil, M., Asselin, O., and Rechid, D.: Impacts of extreme land-use change on wind profiles and wind energy according to regional climate models  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1851, https://doi.org/10.5194/egusphere-egu24-1851, 2024.

EGU24-2418 | ECS | Posters on site | ERE2.5 | Highlight

Assessing the future solar resources over India at 1.5°C and 2°C warming worlds 

Sushovan Ghosh, Dilip Ganguly, and Sagnik Dey

India aspires to increase its reliance on renewable energy sources to fulfil its climate commitments. Among renewables, Solar Photovoltaic (SPV) energy has grown rapidly around the world, including in India. However, little is known about how solar dimming and global warming may affect solar power over the region in the future. The production of SPV energy is influenced by meteorological parameters, highlighting the concerns related to grid stability, intermittency, and reliability caused by weather-induced variability.  

Under the Paris Agreement, all the nations agree to restrict the global warming to “well below” 2°C above pre-industrial levels and, if possible, “pursue” efforts to limit warming at 1.5°C. Therefore, it is imperative to understand future climate change and their spatial heterogeneity at 1.5°C and 2°C warming for developing  strategies for renewables.

This research examines the distribution and variability of India's solar resources by utilising state-of-art global climate models from Coupled Model Intercomparison Project phase 6 (CMIP6) and CMIP6 - NASA Earth eXchange Global Daily Downscaled Projections (NEX-GDDP). The analysis of global mean temperature changes reveals that the 2030s and 2040s will be the decade when majority CMIP6 models reach 1.5°C and 2°C warming under SSP2-4.5 (intermediate emission pathways) and SSP5-8.5 (high emission) scenarios respectively with respect to  pre-industrial period (1850–1900).

We find that under the intermediate (high) emission scenarios, the annual mean surface solar radiation over the Indian landmass will decrease by -8±3 Wm-2 (-5±2 Wm-2) relative to the baseline period (1985-2014) at 1.5°C global warming. An additional 0.5°C of warming (at a global warming level of 2°C) results in a comparatively smaller decline in surface solar irradiance with respect to baseline under both scenarios. At 1.5°C and 2.0°C global warming, most regions are anticipated to experience an increase in surface irradiance under the SSP5-8.5 scenario, as compared to SSP2-4.5. The magnitude and direction of change of aerosols, clouds and associated meteorological parameters needs to be explored further. 

This research will contribute to crucial planning and decision-making processes concerning India and other nations with similar interests.

How to cite: Ghosh, S., Ganguly, D., and Dey, S.: Assessing the future solar resources over India at 1.5°C and 2°C warming worlds, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2418, https://doi.org/10.5194/egusphere-egu24-2418, 2024.

EGU24-2672 | Posters on site | ERE2.5

An Evaluation of Solar Irradiance Projected by CMIP6 Models Toward Long-Term Projection of Climate Change 

Chang Kim, Hyungoo Kim, and Jin Young Kim

This study assesses the reliablity of CMIP6 models in projecting solar irradiance, a crucial aspect of climate dynamics. While extensive scrutiny has been given to historical data from 1975 to 2000, our primary focus is directed towards assessing the models' performance from 2010 to 2020 and their predictive efficacy for the future. Through a meticulous methodology involving statistical comparisons, validation against measurements, and consideration of external factors, we found that CMIP6 models commendably aligned with observed solar irradiance during the historical period, showcasing their adeptness in replicating past climate conditions. However, an in-depth analysis of the recent decade unveiled deviations from observed solar irradiance, prompting concerns regarding the models' adaptability to the swift pace of contemporary climate change. Shifting our gaze to the prospective view, we explore the models' robustness in adapting to emerging climatic trends and emphasize the necessity of continuous refinement, incorporation of real-time data, and a comprehensive understanding of external factors to enhance accuracy in future predictions. Rapid climate change introduces uncertainties such as aerosol concentrations, greenhouse gas emissions, and solar variability, posing challenges that necessitate constant model adjustment. The implications for climate change mitigation are significant, as reliable solar irradiance predictions inform decisions on renewable energy adoption, agriculture planning, and climate adaptation measures. In conclusion, this study bridges the gap between historical evaluations and future projections, providing valuable insights for policymakers, researchers, and stakeholders invested in mitigating the impact of climate change. Continuous refinement of CMIP6 models and a holistic approach to understanding external factors are crucial for building a robust foundation in addressing the challenges posed by climate change in the coming decades.

How to cite: Kim, C., Kim, H., and Kim, J. Y.: An Evaluation of Solar Irradiance Projected by CMIP6 Models Toward Long-Term Projection of Climate Change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2672, https://doi.org/10.5194/egusphere-egu24-2672, 2024.

EGU24-5810 | ECS | Orals | ERE2.5 | Highlight

Investigation of low wind events over Germany from high resolution regional climate models 

Irem Isik Cetin, Thomas Frisius, Elke Keup-Thiel, and Diana Rechid

Wind energy has become one of the most important mitigation options for climate change over the last decades. However, variability and availability of wind are also expected to be changed due to climate change. For this purpose, the KliWiSt project has been initiated to determine the influence of climate change on wind energy site assessments in Germany. Within the scope of the project, many aspects of climate change impacts on wind energy have been studied to determine uncertainties about the topic and to develop recommendations for actions. Although there are many studies in literature which evaluate the effects of climate change on wind in the upcoming decades, low wind events are scarcely investigated so far. However, low wind events pose a risk for achieving long term renewable energy targets and ensuring stability of the electricity grids. Wind drought is increasingly becoming a significant phenomenon which determines low wind energy production due to extreme low wind resources.

In this study, we have investigated the frequency of low wind events in Germany due to climate change until the end of the 21st century by using an ensemble of high-resolution regional climate model simulations available from the EURO-CORDEX initiative. We also evaluated the performance of the regional climate models with data from different observation stations and with re-analysis data sets. For our investigation we used thresholds of 2 m/s and 3 m/s for wind speed at 10 m and 100 m – respectively for – calculating “calm wind” climate indices. The threshold is determined as 3 m/s (at 100 m height) for low wind events since most of the wind turbines starts wind energy production at this value (“cut in” wind speed). We used two different benchmark data sets (ERA5 and CERRA) to determine historical variation of “calm days” over Germany and to evaluate the performance of the high-resolution regional climate models. Moreover, seasonal, annual, and spatial distributions of low wind events are investigated for Germany where the country has already a high installed wind energy capacity and ambitious renewable energy targets. The study aims to determine trend and frequency of low wind events in the past and future at different terrain conditions at different time scales from different regional climate models. The anticipated results of the study and the project are expected to give insight for policy makers and stakeholders from the renewable energy sector.* 

*This study is part of the project "The influence of climate change on wind energy site assessments (KliWiSt)" which is funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK).

How to cite: Isik Cetin, I., Frisius, T., Keup-Thiel, E., and Rechid, D.: Investigation of low wind events over Germany from high resolution regional climate models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5810, https://doi.org/10.5194/egusphere-egu24-5810, 2024.

EGU24-5874 | ECS | Posters on site | ERE2.5

Comparing ERA5 and model data to observations for wind resource assessment – a case study from Tanzania  

Alexander Chamberlain-Clay and Elisabeth Thompson

The ERA5 reanalysis is established as a key source of gridded wind-speed information for much of the world, having better performance and higher resolution (30km) than other reanalysis products. It’s used as a source of truth for driving wind-power models, and verifying ML predictions, especially in the absence of observational measurements. However, verification of ERA5 has mostly focused on Europe and the northern hemisphere, not examining performance in low-observation regions such as East Africa, where wind power investment and green energy provision is crucial to climate goals. As part of the FOCUS-AFRICA project, this study investigates how well the ERA5 reanalysis represents the climatology of 19 different observation sites in Tanzania and compares them to 3 CORDEX-Africa models driven by ERA-Interim at a similar resolution to ERA5, and one convection-permitting 4.4km resolution model (CP4A). ERA5 is shown to perform poorly at representing inland wind climatologies in Tanzania, with Perkins skill scores of 0.21-0.62 (1 is perfect), in comparison to European inland stations showing an average a score of ~0.8 in previous studies. This is caused by underestimations of mean wind speed compared to observations for inland sites.  The CP4A model performs best with scores of 0.54-0.79, despite the fact this model is not forced by real-world conditions.

These results show the need for caution when using ERA5 as a basis for any wind resource assessment or model validation. It also indicates that wind resource in East Africa may be underestimated, which would have negative impacts on investment decisions in the region. 

How to cite: Chamberlain-Clay, A. and Thompson, E.: Comparing ERA5 and model data to observations for wind resource assessment – a case study from Tanzania , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5874, https://doi.org/10.5194/egusphere-egu24-5874, 2024.

EGU24-6025 | ECS | Orals | ERE2.5

From multi-decadal energy planning to hourly power dispatch: evaluating the reliability of energy projections in the Southern African Power Pool 

Arianna Leoni, Nicolò Stevanato, Angelo Carlino, Andrea Francesco Castelletti, and Matteo Giuliani

Development pathways for Sub-Saharan Africa project a substantial increase in population and living standards and, correspondingly, in the regional energy demand. To accommodate future energy needs, power and energy system communities have been developing least-cost optimization models to support long-term transformational energy system planning and the transition to carbon neutrality at the African continental scale.  

However, these models usually focus on annual or seasonal energy balances and overlook higher time resolution dynamics that can actually lead to short but impactful events when considering the expansion of renewable energy share. Indeed, the variability of renewable generation and power demand can lead to significant risks, including elevated electricity prices, transmission line overload, and power generation deficits. 

In this work, focusing on the Southern African Power Pool, we couple an energy system planning model, OSeMOSYS-TEMBA, and a power system model, PowNet, to obtain higher temporal resolution characterization of the energy system evolution in the future.

 OSeMOSYS-TEMBA is a long-term energy system planning model producing cost-optimal trajectories of capacity expansion for different technologies for all the countries in continental Africa with a seasonal resolution from 2015 to 2070. Yet, OSeMOSYS-TEMBA is not resolved enough to account for power grid reliability under high penetration of renewables, where flexible operations and power grid reliability are crucial, and might substantially affect model projections.

PowNet is a least-cost optimization model running on an annual horizon with hourly resolution and optimizes the dispatch of power from each source as well as the usage of transmission lines, constrained to the power capacity available according to the long-term energy planning provided by the OSeMOSYS-TEMBA model. We assess the difference in generation mix, the impact on transmission lines overloading, power generation deficits in 2030 under three climate policy scenarios: no climate policy, and constrained to 2.0°C and 1.5°C warming constraining emissions to a consistent pathway. 

Results indicate power generation deficits and transmission lines overloading are observed in many countries, especially during the night. These impacts are to be associated with insufficient total power system capacity to meet power demand due to the low time and spatial resolution of the energy system model. Indeed, the increased dependency on variable renewable resources, and a higher resolution demand profile emphasize the need to further expand total capacity, the importance of flexible generation adopting a diverse energy portfolio, and the potential benefits of increasing transmission lines’ capacity. Finally, the storage of unused water for future power generation within the available reservoirs might potentially reduce the power deficit. These results show the importance of the assumptions embedded in the energy system model and motivate methodological improvements to design coupled energy and power system pathways that remain reliable at high spatial and time resolution.



How to cite: Leoni, A., Stevanato, N., Carlino, A., Castelletti, A. F., and Giuliani, M.: From multi-decadal energy planning to hourly power dispatch: evaluating the reliability of energy projections in the Southern African Power Pool, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6025, https://doi.org/10.5194/egusphere-egu24-6025, 2024.

EGU24-6374 | Orals | ERE2.5

A wind energy resource analysis in the Iberian Penindula under climate projections 

M. Yolanda Luna, Javier Díaz-Fernández, Alonso García-Miguel, Carlos Calvo-Sancho, Ricardo Castedo, José J. Ortega, Pedro Bolgiani, Mariano Sastre, and María Luisa Martín

The wind resource in the Iberian Peninsula has been analyzed using wind climate projections from the XX century to the end of the XXI century of the SSP5-8.5 scenario obtained from the MRI-ESM2.0 global climate numerical model. Six-hour wind speed and direction are seasonally grouped and from them, both the production of electrical power and the intensity of wind energy have been estimated throughout the temporal record. Two periods are considered in the dataset: the historical (1950 – 2014) and the future (2015-2100) periods. The non-parametric Mann-Kendall trend test is applied to identify significant wind energy intensity trends and the non-parametric Mann-Whitney test is applied over the entire domain's all-grid points to statistically evaluate the significant differences between wind energy intensity of different time periods. For an estimation of the evolution of the electrical power throughout the XXI century, the latest generation wind turbine SG 7.0-170 from Siemens-Gamesa has been used as a reference. Considering winter as the season of maximum wind energy production, the results show a future higher electricity production compared to the selected historical period in almost the entire Iberian Peninsula, although there is a decreasing production trend throughout the century. The remainder seasonal results indicate a general drop in electrical power due to a decrease of wind resource in the whole Peninsula throughout the century, especially in autumn with significant losses of more than 2 MW of electricity production in many Portuguese areas on the western coast of the peninsula.

How to cite: Luna, M. Y., Díaz-Fernández, J., García-Miguel, A., Calvo-Sancho, C., Castedo, R., Ortega, J. J., Bolgiani, P., Sastre, M., and Martín, M. L.: A wind energy resource analysis in the Iberian Penindula under climate projections, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6374, https://doi.org/10.5194/egusphere-egu24-6374, 2024.

This study presents the impact of climate change on the wind and solar power generation potentials over South Korea considering ensemble projections from downscaled high-resolution bias-corrected future climate change scenario data. Under future global warming, solar power potentials over South Korea are projected to decrease in spring (March-May) and winter (December-February) seasons relative to present climate in the late 21st century (2081-2100), particularly showing a relatively large decrease in the northern part of South Korea. The decrease tendency is more significant and larger in the high-CO2 emission scenario (SSP5-8.5) than the low-CO2 emission scenario (SSP2-4.5). The projected decrease in solar power potential in spring is mainly due to increased air temperature by future global warming and the decrease in winter is attributable to the projected increase in the air temperature and the decrease in solar radiation at the surface. Wind power potentials which are estimated with the wind energy density is generally projected to decrease with future global warming in all seasons except for summer. This decrease tendency is also larger in the late 21st century of the SSP5-8.5 scenario, especially over the southern part of South Korea in winter and spring and over the northern part in fall. These results may help optimize the regional renewable energy generation system development and plans

How to cite: Kim, S. T.: Changes in Solar and Wind Power Generation Potentials over South Korea under Future Global Warming., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7322, https://doi.org/10.5194/egusphere-egu24-7322, 2024.

EGU24-7974 | Orals | ERE2.5

Simulating Reserve Power Systems in Future Climates: Bias Adjustment Approaches for Regional Climate Projections 

James Fallon, David Brayshaw, John Methven, Kjeld Jensen, and Louise Krug

Critical infrastructure, such as telecommunications networks and hospitals, are in many cases required to have reserve power systems in place, mitigating transmission network failures and protecting against national power grid outage. A previous case study of Great Britain (GB) telecommunications assets implemented a temperature-driven model of infrastructure electricity demand (Fallon et al., 2023), used to plan reserve capacity installation sufficient to meet the highest anticipated 5-day periods of energy consumption (or other regulatory targets). Extending this work with climate models (UKCP18), we demonstrate that the capacity planning framework reliant upon reanalysis observations underestimates capacity installation appropriate to meet historic weather risk, while assessments are improved using historic period climate model outputs. Additionally, climate projections simulating future periods support further upgrading the installed reserve capacity beyond historic requirements.

Quantile-correcting bias adjustments of climate model outputs can address significant discrepancy between the model world and observations temperature distributions across the historic period (model timespan where global climate matches recent observations). Uncorrected, this climate model error leads to an exaggerated frequency of extreme temperature events, hence overestimating the reserve capacity requirement. But under a quantile-correcting approach, assuming a consistent underlying representation of the weather dynamics, the temperature distribution is adjusted to match the reanalysis distribution.

Temperature delta-shifts are calculated to represent the GB historic period climate variability observed across model ensemble members. The resulting infrastructure electricity demand timeseries are compared against timeseries produced from historic period temperature data adjusted by quantile delta mapping, demonstrating that reanalysis data alone is insufficient to capture the greater reserve capacity requirements predicted by quantile delta-mapping of climate model outputs in the historic time period.

Using future period climate model outputs, we compare three alternative treatments of model temperature timeseries simulating future climate: a delta-shift adjustment of reanalysis data, a regional trend-preserving mean bias adjustment, and quantile delta mapping. In each case, reserve capacity requirements increase (5% to 10% increase in a world 2.0°C above pre-industrial temperatures). There is significant variability across different model ensemble members, and sensitivity to individual weather years.

Reserve system operators can use the approaches outlined to make an informed assessment of the need for upgrading or installing new reserve systems, ensuring the stability and resilience of critical infrastructure assets. The consistent trajectories across different approaches and model ensemble members may improve confidence in results, whilst individual model ensemble members can be investigated to identify potential ‘worst case’ outcomes.

How to cite: Fallon, J., Brayshaw, D., Methven, J., Jensen, K., and Krug, L.: Simulating Reserve Power Systems in Future Climates: Bias Adjustment Approaches for Regional Climate Projections, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7974, https://doi.org/10.5194/egusphere-egu24-7974, 2024.

EGU24-8178 | ECS | Orals | ERE2.5

Strength of co-variability of energy droughts highly region dependent  

Bram van Duinen, Lieke van der Most, Michiel Baatsen, and Karin van der Wiel

The European electricity system is becoming increasingly dependent on weather conditions, which influence both electricity demand and production. Non-linear dependence of the electricity system on the weather conditions can lead to energy droughts – high demand coinciding with low renewable energy production – even under non-extreme meteorological conditions. Weather conditions driving energy droughts can transcend national boundaries, which leads to the possibility that multiple countries experience concurrent energy droughts, potentially leading to a widespread energy crisis. We examine the interplay between large-scale weather conditions and the risks of co-occurrence and opportunities of disjoint occurrence of energy droughts in renewable electricity systems in European countries. We analyse 1600 years of modelled energy data against meteorological conditions from large ensemble climate model simulations to identify patterns of co-variability of energy droughts in the present-day climate.

We find a strong spatial variability in the risk for concurrent energy droughts within Europe, depending on a country’s renewable energy mix and the region's response to specific large-scale meteorological patterns (weather regimes). Some countries, such as Latvia and Slovenia, mostly experience energy droughts isolated from their neighbouring countries. However, we also find clusters of countries that experience concurrent energy droughts. This is the case for the North Sea region, and many countries in central/eastern Europe. Here, there is limited potential for cooperation, putting these countries more at risk of energy crises. Finally, we differentiate between moderate and extreme energy droughts, which have different co-occurrence signatures. This implies that an interconnected electricity grid has potential to resolve some moderate events, but is less effective in the extreme events.

How to cite: van Duinen, B., van der Most, L., Baatsen, M., and van der Wiel, K.: Strength of co-variability of energy droughts highly region dependent , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8178, https://doi.org/10.5194/egusphere-egu24-8178, 2024.

EGU24-8655 | ECS | Orals | ERE2.5

Offshore Solar Farm Assessment and Uncertainty Determination for the United Arab Emirates 

Encarni Medina-Lopez, Jasmina Lazic, and Latifa Yousef

Floating offshore solar farms (OSF) are an attractive option for solar energy generation, as they help avoid land competition with other uses. Planning the deployment of OSF requires assessments for site selection, which are primarily based on energy yields, in addition to other considerations. The yields are determined through evaluations using climate and oceanic variables. Uncertainty in these variables can propagate to further uncertainty in yield estimations, which ultimately can lead to significant consequences in the cost of energy. In this work, we propose the development of a novel method to assess the viability of OSF considering insolation uncertainty, with a focus on the United Arab Emirates (UAE) region. Open-source satellite data is utilized to conduct initial site assessments, and produce a set of viable locations based on parameters that include solar irradiance, ambient temperature, sea surface temperature, wind speed and precipitation. Validation of the viable locations will be done through the deployment of meteorological instrumentation, to collect in-situ measurements for a minimum of one year. Machine learning techniques are examined to quantify the uncertainty, followed by determination of impacts on levelized cost of electricity (LCOE) and savings based on uncertainty reduction.

How to cite: Medina-Lopez, E., Lazic, J., and Yousef, L.: Offshore Solar Farm Assessment and Uncertainty Determination for the United Arab Emirates, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8655, https://doi.org/10.5194/egusphere-egu24-8655, 2024.

EGU24-11262 | ECS | Posters virtual | ERE2.5 | Highlight

Balancing seasonality in decarbonising electricity systems worldwide 

Anasuya Gangopadhyay, Rajat Masiwal, and Ashwin K Seshadri

Decarbonizing electricity grids across the world will be increasingly impacted  by systematic seasonal variation in wind speed and solar irradiance as well as seasonally varying patterns of demand, more so in the context of progressive decarbonization of energy services such as winter heating. These seasonal variations are governed by local meteorology which also has large-scale manifestations impacting entire electricity grid systems. Using ERA5 reanalysis, we quantify the amplitude of seasonality in wind speed and solar insolation across the world and consider the impacts on grid scale generation. Owing to effects of seasonal evolution of solar insolation as well as the seasonal cycle of cloudiness, the seasonal cycle amplitude for solar insolation at the surface is much larger in higher latitudes. For horizontal winds, high seasonal amplitudes are experienced in global tropical monsoon regions and higher latitudes associated with meridional shifts in mid-latitude zonal winds. In general, wind power availability is much higher in high-latitude winters.

Seasonal weather variation also drives electricity demand for heating and cooling, which is a major part of the total electricity consumption of many regions. While many large electricity consumers including China, US, India, and Brazil experience peak electricity consumption during summer, most European countries have higher demand during winter, giving a double peak structure for global monthly electricity demand. Many large electricity consuming countries experience nearly 40 percent variation in electricity demand between seasons. Solutions to bridge large seasonal variations in demand and generation, e.g. bulk energy storage, excess of wind and solar capacity, renewable portfolio design, and demand-side management present critical challenges.

This paper will consider whether a portfolio of such solutions is adequate to balance seasonal variability in supply and demand. We will characterize the main patterns of seasonal load variability across countries, explore whether within-country wind and solar variability are well matched with these patterns, and consider the role of excess capacity and storage in bridging the gaps, in context of limitations of seasonal-scale demand side management. Bridging seasonal-scale gaps and mitigating the impacts of various manifestations of seasonality remains an important roadblock towards net zero electricity systems worldwide, and we will survey the most promising solutions to this challenge.

How to cite: Gangopadhyay, A., Masiwal, R., and K Seshadri, A.: Balancing seasonality in decarbonising electricity systems worldwide, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11262, https://doi.org/10.5194/egusphere-egu24-11262, 2024.

EGU24-15943 | ECS | Posters on site | ERE2.5

Achieving renewable energy-centered sustainable development futures for rural Africa 

Giacomo Falchetta, Adriano Vinca, Gregory Ireland, Marta Tuninetti, André Troost, Manfred Hafner, Edward Byers, and Ackim Zulu

Multi-dimensional and overlapping Nexus challenges affect many parts of rural sub-Saharan Africa. More than 90% of cropland is rainfed, less than one third of households have electricity at home, more than 15% of people report insufficient food intake and more than 40% of people live below the poverty line. Climate change impacts on vulnerable systems with limited adaptive capacity and strong population growth are increasing the magnitude of the challenge. As a result, there is a strong need for multi-level, multi-sector interventions (from national policies to regional/river basin-scale planning, to local planning and investment). To implement such actions, it is key to assess solutions (technology and investment) and appraise their feasibility and implementation potential (from both a policy and a financial point of view). In this study, we soft-link bottom-up process-based water and energy demand and techno-economic infrastructure assessment models into a multi-node, national Nexus-extended Integrated Assessment Model (MESSAGEix-Nexus) for supply and investment assessment. Based on the integrated modelling, we obtain an understanding of the role of an explicit consideration of (productive) energy access jointly with Water-Agriculture-Food interlinkages for rural Nexus infrastructure requirements, investment, and sustainable development objectives. This demonstrates how climate impacts and water and energy needs affect each other and jointly shape infrastructure and investment pathways. Then, by linking technical models with business models analysis, we are able to assess feasibility of implementation and appraise which are the key micro and macro determinants to ensure feasibility, investment, and uptake of small-scale Nexus infrastructure, crucial for rural development and adaptation to changing climate conditions. Altogether, our research demonstrates how national-scale integrated modelling with an explicit focus on Nexus interlinkages allows for assessing locally-relevant demand sources and investment needs, and their implications for sustainable development. In turn, this allows for deriving  policy and investment-relevant insights.

How to cite: Falchetta, G., Vinca, A., Ireland, G., Tuninetti, M., Troost, A., Hafner, M., Byers, E., and Zulu, A.: Achieving renewable energy-centered sustainable development futures for rural Africa, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15943, https://doi.org/10.5194/egusphere-egu24-15943, 2024.

EGU24-17572 | Orals | ERE2.5

Uncertainties in climate projections and the economics of wind farm portfolios 

Ana Lopez, Kai Lochbihler, and Gil Lizcano

The deployment of low carbon affordable energy generation technologies plays a crucial role to achieve the Paris Agreement long-term goal to reduce global greenhouse gas emissions to limit global temperature increase well below 2ºC above pre-industrial levels, and pursue efforts to limit it to 1.5º C above pre-industrial levels. In particular wind power installed capacity is projected to increase exponentially over the next few decades. Wind power generation is, however, weather-dependent. Therefore, understanding the variability of wind, how it might be affected by climate change, and how this affects the economics of wind projects seems vital as countries continue to invest in wind energy.

At the global level, the last IPCC report (IPCC AR6 WGIII, 2022) states that the climate change impact on future wind resources will be limited. Regional studies, however, show that wind resources are projected to increase for instance over Northern Europe and decrease over Southern Europe. In North America, various studies have low agreement for the changes on future resources, in part because the inter-annual variability is larger than the projected changes due to climate change. For South America, some studies find increases in wind resources in windy areas. In general, the compounding of the anthropogenic climate change signal with high spatial and temporal wind variability can lead to large uncertainties in the projected impacts of climate change on wind resources, and as a result, on the economics of a project. 

In this study we showcase a methodology to analyze the impact of climate change on the economic indicators of a portfolio of wind farm projects across Europe. Projections of changes in wind resources are obtained using an ensemble of Coupled Model Intercomparison Project 6 (CMIP6) global climate models statistically downscaled to correct biases and increase the spatial resolution. Uncertainties in climate projections are taken into account by considering an ensemble of climate models and different emissions scenarios as represented by the Shared Socioeconomic Pathways (SSPs) . A series of assumptions about the features of a representative wind farm and its key economic parameters (e.g. capital expenditures and operational costs) are made to compute two common economic indicators: the Internal Rate of Return (IRR) and the Levelized Cost of Energy (LCOE).

By varying the production following the different climate scenarios, we analyze the impacts of climate change on the economics of the portfolios for different time horizons in the future. We find that the effect of changes of resource on IRR and LCOE depend on the region, emissions scenario and projection period. In the short term, changes are often masked by the internal variability of the resource on the site.

We also discuss, from the point of view of our role as climate services provider for the wind industry, the limitations of the data provided in the CMIP6 experiment, and some of the data needs we have identified.

How to cite: Lopez, A., Lochbihler, K., and Lizcano, G.: Uncertainties in climate projections and the economics of wind farm portfolios, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17572, https://doi.org/10.5194/egusphere-egu24-17572, 2024.

EGU24-18490 | ECS | Orals | ERE2.5

The Nepalese theoretical hydropower potential in a changing climate 

Vera van der Veen, Sanita Dhaubanjar, Sonu Khanal, and Walter Immerzeel

With steep elevation gradients and an abundance of water, Nepal is one of the leading countries in hydropower capacity. This potential is largely unutilised; representing a significant untapped renewable energy resource that could help Nepal achieve its emissions target and improve its energy security. However, future climate projections suggest changes in discharge seasonality, which will impact the hydropower potential. Hence, we provide an estimate of current and future theoretical hydropower potential in the four large basins in Nepal, namely Mahakali, Karnali, Gandaki, and Koshi. We use current and future discharge simulated in the Spatial Processes in Hydrology (SPHY) model from a previous study to force the theoretical potential module in the Hydropower Potential Exploration (HyPE) model. The HyPE model set up for Nepal is run for 48 combinations of future climate scenarios, combining temperature change in the range of 3°C to 8°C and precipitation change in the range of -30% to 40%. Average monthly discharge components (baseflow, rainfall runoff, snowmelt, and glacier melt) are analysed separately for the reference period (1979-2018), mid-century (2036-2065), and end of century (2071-2100). For each time horizon, we evaluate the relative contribution of the discharge components to the theoretical hydropower potential and quantify the impact of future changes in discharge seasonality.

 

The Indian summer monsoon dominates the discharge patterns in Nepal. The historical water balance shows an overlap in the peak contributions from rainfall and glacier melt to discharge with both occurring in July and August. A shift in the peaks from these components is not apparent for the climate scenarios considered. However, the peak from snow melt contribution shifts one to two months earlier for most climate scenarios in all basins. Such shift in the seasonal discharge composition could prove promising for stabilizing year-round hydropower generation. At 5 km resolution, we estimate the total theoretical hydropower potential for the four Nepalese basins to be 1170 TWh/yr during the reference period. While challenges remain in accurately simulating discharge in mountainous and data-scarce basins in Nepal contexts using SPHY, the majority of the projections suggest a promising increase in the monthly average discharge and the subsequent monthly theoretical hydropower potential. We observe an increase in total Nepalese hydropower potential up to 22% for the mid-century and 36% by the end of the century. Variations across the basins occur and a decrease in hydropower potential is also observed for the dry future climate scenarios. However, it is important to note that theoretical potential may not be a realistic indicator for hydropower development. Only a small part of the theoretical potential may be technically and financially feasible and an even smaller part may be sustainable. Nonetheless, our research provides a first step to the identification of hydropower project sites considered within the context of a changing climate.

How to cite: van der Veen, V., Dhaubanjar, S., Khanal, S., and Immerzeel, W.: The Nepalese theoretical hydropower potential in a changing climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18490, https://doi.org/10.5194/egusphere-egu24-18490, 2024.

EGU24-3862 | ECS | Posters on site | ERE2.6

Integrated geothermal exploration of Hongchailin geothermal field in Taiwan using seismic velocity and resistivity tomography with unsupervised learning analysis 

Hong-Mao Huang, Hsin-Hua Huang, Yung-en Yu, Gong-Ruei Ho, Min-Hung Shih, Ya-Chuan Lai, Po-Li Su, Hung-Yu Yen, Tsung-Chih Chi, Cheng-Horng Lin, Jian-Cheng Lee, Yue-Gau Chen, and Sun-Lin Chung

Geothermal energy serves as one of sustainable and low-emission energy sources with the potential to mitigate climate change and enhance energy security. It offers a viable substitute for conventional fossil fuels or electrical energy. The Hongchailin area in Ilan, Taiwan has been considered as a potential geothermal energy field in recent years. To investigate possible geothermal sources in Hongchailin, a dense seismic array comprising 186 geophones is deployed over a 5 × 4 km area covering the probable geothermal field between August 2022 and January 2023. A vibroseis experiment was operated along multiple lines across the array with 12-second sweep-frequency signals from 6 to 96 Hz. To retrieve clear vibroseis-generated P-wave arrivals, we first remove the sweep signals from the raw waveforms by the cross-correlation method, and stack the processed waveforms from successive co-site shots with the Phase-Weighted Stacking (PWS) method to improve the signal-to-noise ratio. We use the Recursive-STA/LTA method for P-wave arrival picking. Visual inspection and additional criteria are made for confirming and refining the accuracy of P-arrivals. Lastly, a total of 41,095 P-arrivals are collected and used for seismic tomographic inversion. The velocity model shows several velocity anomaly zones in good spatial correlation with the resistivity model, although the resolvable depth of the model is limited to ~1 km. It demonstrates the active-source seismic tomography as a valuable geothermal exploration tool. Further, we employ unsupervised learning methods to classify and explore the resistivity-velocity relationships in each cluster. The preliminary results indicate a positive linear correlation for some regions but negative for some others, implying different materials such as rock composition or fluid content. These findings provide valuable insights for comprehensive understanding of geothermal resources in the Hongchailin area.

How to cite: Huang, H.-M., Huang, H.-H., Yu, Y., Ho, G.-R., Shih, M.-H., Lai, Y.-C., Su, P.-L., Yen, H.-Y., Chi, T.-C., Lin, C.-H., Lee, J.-C., Chen, Y.-G., and Chung, S.-L.: Integrated geothermal exploration of Hongchailin geothermal field in Taiwan using seismic velocity and resistivity tomography with unsupervised learning analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3862, https://doi.org/10.5194/egusphere-egu24-3862, 2024.

Nemrut Volcano, which surfaces in the north of Bitlis province in Türkiye, is one of the most important active members of the Quaternary volcano sequence in Eastern Anatolia. 


According to historical records, the last volcanic activity in the region was in 1441 in the north of Nemrut Caldera and the basalt flows formed as a result of this volcanic activity caused Nemrut to be one of the last known active stratavolcano volcanoes in Turkey. It is possible to talk about a formation mechanism in which the intense tectonism in Eastern Anatolia is also effective.


Nemrut Caldera, which has a surface area of approximately 36 km2, has a total of 5 lake formations, two of which are large, and Lake Nemrut is known as the second largest caldera lake in the world. Water temperatures in the lakes in the caldera vary between 16-41 0C. Hot water and gas outflows are observed in and around the caldera, which makes the region interesting for both geoscientists and geothermal energy investors. Due to the volcanic activity extending towards the north-east, there are hot water springs formed due to volcanism on the shore of Lake Van in the east of the region. 


The potential for geothermal energy applications in the region is still being investigated. In this context, the surface geology of the caldera and its surroundings was analysed and a series of hydrogeochemical investigations were carried out by taking samples from the hot and cold waters in and around the caldera and evaluating some critical elements. According to the results of chemical analyses and isotope analyses, since the hot-cold water mixture is intensely observed in the region, an exploration drilling to be carried out at the correct location in the region is also important in terms of understanding the reservoir levels and conditions.

How to cite: Tut Haklıdır, F., Şengün Çetin, R., and Görgülü, İ. S.: Geothermal exploration in the Nemrut Caldera and surroundings (Eastern Anatolia-Turkey): Trying to unlock of geothermal potential in one of the world's largest calderas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3906, https://doi.org/10.5194/egusphere-egu24-3906, 2024.

EGU24-5315 | ECS | Posters on site | ERE2.6

Reactivation of caldera structures in active extensional settings: implication for geothermal exploration 

Daniele Maestrelli, Giacomo Corti, Marco Bonini, Derek Keir, Eugenio Trumpy, Pietro Facincani, Paola Vannucchi, Chiara Del Ventisette, Domenico Montanari, and Federico Sani

Collapsed calderas are prominent volcano-tectonic features occurring in active tectonic settings and bear intrinsic risks associated with their explosiveness. Nonetheless, they also represent key targets for geothermal fluid exploration, their structures being often the preferential pathway for geothermal fluids migration. In active tectonic settings such as continental rifts, caldera faults may be reactivated, enhancing therefore their permeability. However, specific structures may be subject to clamping, consequently reducing their secondary porosity. Discriminating if and how caldera structures may respond to tectonic stresses, represents therefore a critical question to address when calderas become the locus of potential geothermal exploration. We performed an experimental series of analogue models of caldera collapse exploring whether caldera structures may reactivate under extensional tectonic conditions. This analysis is important for evaluating which caldera fault segments may be regarded as the best potential target for fluid interception. Our experimental series shows that regional extension and fault dip can explain the reactivation of specific caldera fault segments. In particular, outer normal ring faults do reactivate under extensional conditions only in the sectors trending orthogonally to the direction of extension. Conversely, inner outward-dipping reverse faults do not reactivate, likely because of their lower dip angle, whichever their trend might be. This implies that inward-dipping normal faults trending orthogonal to direction of extension likely increase their permeability, thus becoming a favourable locus for geothermal fluid migration and therefore a preferable target for exploration. Conversely, our models show that sectors of inward-dipping normal caldera faults trending parallel to the direction of extension may experience clamping, and so reducing their secondary permeability. Therefore, our setup, with due approximations and limitations, represents a useful predictive tool for identifying potential target structures for geothermal exploration at caldera sites. The model setup can also provide insights into similar caldera systems developing in other geological settings (e.g., compressional).

How to cite: Maestrelli, D., Corti, G., Bonini, M., Keir, D., Trumpy, E., Facincani, P., Vannucchi, P., Del Ventisette, C., Montanari, D., and Sani, F.: Reactivation of caldera structures in active extensional settings: implication for geothermal exploration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5315, https://doi.org/10.5194/egusphere-egu24-5315, 2024.

In Germany, the geothermal development takes place at different speeds regionally. Compared to the Molasse Basin in South Germany, the North German Basin is just at the beginning of its geothermal exploration.

The project “Warm-Up” aims to evaluate the geothermal potential in the North German Basin and to promote its geothermal development. One target for detailed investigations are the sandstones of the Dogger. This Jurassic reservoir with nearly full extent in the North German Basin was a worthwhile target for the Oil Industry based on its reservoir quality and its oil content. A large volume of data, including geological and lithological one, with special focus on hydraulic data, porosity-permeability relationships and their links to the facies have been evaluated. Where core data is not available, the extraction of hydraulic properties from well logs is necessary. Different methods for deriving porosity and permeability from well logs are tested and checked against core data. If hydraulic test results are available the comparison of those in-situ data to logging and core measurements is of crucial importance. In reality, a full set of logging, core and test data is only available in a few wells, despite the large effort, taken by the hydrocarbon industry in the past. Therefore, it is important to develop workflows, that allows the prediction of the productivity of the Dogger sandstones in areas with fewer data and to reduce the exploitation risk. Companies like local municipal utility or majors can utilize this knowledge to unlock the geothermal potential of the North German Basin.

How to cite: Weber, I. and Tischner, T.: Using Oil & Gas Borehole Data to Unlock the Geothermal Potential of the Dogger Sandstone in the North German Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5413, https://doi.org/10.5194/egusphere-egu24-5413, 2024.

EGU24-5595 | Posters on site | ERE2.6

New data for a model update of the Waiwera geothermal reservoir in New Zealand 

Michael Kühn, Paul Viskovic, and Thomas Kempka

Waiwera is a small coastal village located on New Zealand's North Island. The geothermal reservoir below the town consists of compacted and cemented sandstones and siltstones of the Waitemata Group [1]. These are some 400-m thick and have been folded, faulted and fractured by tectonic processes throughout the entire depth. The source of the hot water is not well understood because the deeper structure of the field has mainly been inferred from the spatial distribution of thermal water from producing bores. An inferred fault zone at the base of the reservoir is thought to be the source of the upwelling thermal water.

The most recent model of Waiwera integrates the depositional environment, mineralogical composition and geological structures [2]. Numerical simulations indicated that further model revisions are required with support by additional field campaigns to increase the knowledge of the complex reservoir geology [3].

In this study, gravity data from 77 new stations were acquired around the greater Waiwera area, modelled and interpreted. Two 2.5D gravity models show a 180-m high, NNW-trending step that may represent either steep topography or a fault downthrow to the east in the basement. The position and size of this step are well constrained, but the feature is too deep to confidently predict the dip, and hence is modelled as being almost vertical. This feature may provide a focus for hot water to rise upwards into the Waiwera geothermal system [4].

Further, radiocarbon analysis of three groundwater samples show that age of the geothermal water at Waiwera is >20,000 years with <0.005% of hydrogeologically young water. Geochemical analyses show possible saltwater intrusion near the coast and the highest observed concentrations of geothermal chemical components near the main production well of the thermal resort, close to the modelled fault location.

New models will be implemented with the updated information to investigate a revised conceptual model. We will test if the assumption of hot water accumulating in sedimentary basins away from Waiwera and travelling laterally up-dip near the base of the Waitemata Group sediments and then rising vertically under the Waiwera township is a feasible hypothesis to better represent the system.

 

[1] Kühn, M., Stöfen, H. (2005): A reactive flow model of the geothermal reservoir Waiwera, New Zealand. - Hydrogeology Journal, 13, 4, 606-626. https://doi.org/10.1007/s10040-004-0377-6

[2] Kühn, M., Präg, M., Becker, I., Hilgers, C., Grafe, A., Kempka, T. (2022): Geographic Information System (GIS) as a basis for the next generation of hydrogeological models to manage the geothermal area Waiwera (New Zealand). - Advances in Geosciences, 58, 31-39. https://doi.org/10.5194/adgeo-58-31-2022

[3] Kempka, T., Kühn, M. (2023): Numerical simulation of spatial temperature and salinity distribution in the Waiwera geothermal reservoir, New Zealand. - Grundwasser, 28, 243-254. https://doi.org/10.1007/s00767-023-00551-8

[4] Präg, M., Becker, I., Hilgers, C., Walter, T. R., Kühn, M. (2020): Thermal UAS survey of reactivated hot spring activity in Waiwera, New Zealand. - Advances in Geosciences, 54, 165-171. https://doi.org/10.5194/adgeo-54-165-2020

How to cite: Kühn, M., Viskovic, P., and Kempka, T.: New data for a model update of the Waiwera geothermal reservoir in New Zealand, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5595, https://doi.org/10.5194/egusphere-egu24-5595, 2024.

EGU24-5687 | ECS | Posters on site | ERE2.6

Geological risk analysis of geothermal developments in the Buda thermal karst area 

Tamara Tóthi, Ábel Markó, Imre Szilágyi, and Judit Mádl-Szőnyi

The Buda Thermal Karst system is one of the best-known hypogenic karst areas. In addition, it is located below the city of Budapest. The groundwater of the confined and unconfined carbonate system is characterised by complex gravity and buoyancy-driven flow. It is associated with a complex geological setup characterised by significant heterogeneity in permeability distribution, resulting in exploration uncertainty. The utilisation of thermal water in the area goes back to the Roman Empire through springs, but from the 19th century, wells have been deepened. In Budapest, outstanding thermal wells and projects have been developed. However, several unsuccessful attempts also occurred in SE Budapest due to geological uncertainty, lack of knowledge and proper pre-analysis.

Motivated by the green transition and the energy crisis, the geothermal utilisation of the thermal water in the area has become the focus of interest nowadays. The geothermal risk assessment can be a helpful tool to quantify the uncertainties of the exploration of such a complex system. In this research, we develop a novel methodology to analyse and quantify the geological risk of geothermal developments, focusing on the deep and thick carbonate reservoir. The new approach is adapted from the petroleum industry and follows the risk assessment scheme of petroleum play analysis.

The methodology was tested in a local study area in northeast Budapest, where the required geothermal capacity for heating was previously determined. Here, the Neogene siliciclastic sediments cover the Triassic carbonates, which serve as thermal water reservoirs. To estimate whether a future geothermal system can provide sufficient capacity, in this study, the probability of success is assessed by evaluating potential geological risk factors which can hinder geothermal production and reinjection. This is done by combining and evaluating datasets on aquifer and water quality, temperature and flow conditions using lithological data, geophysical logs (cavities), temperature-elevation, and pressure-elevation profiles. The outcomes of the research help in decision-making while preparing new geothermal developments.

This research was supported and financed through the KDP-2021 Cooperative Doctoral Programme of the Ministry of Culture and Innovation of Hungary from the source of the National Research, Development and Innovation Fund, grant number: KDP 2021 _ELTE_C 1789026. The research is funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21-2022-00014 project.

How to cite: Tóthi, T., Markó, Á., Szilágyi, I., and Mádl-Szőnyi, J.: Geological risk analysis of geothermal developments in the Buda thermal karst area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5687, https://doi.org/10.5194/egusphere-egu24-5687, 2024.

EGU24-6049 | Orals | ERE2.6

Mineralogical and petrological assessment of selected granites and granodiorites from the Odenwald area, Germany: a crucial step toward the site selection for the GeoLaB underground infrastructure? 

Fiorenza Deon, Ingo Sass, Claire Bossennec, Anselm Loges, Oona Appelt, Lukas Seib, Harald Milsch, and Günter Zimmermann

GeoLaB (Geothermal Laboratory in the Crystalline Basement) started in the beginning of 2023 to plan and build an underground geoscientific laboratory in a fractured crystalline basement. One of the potential selected sites is the Odenwald complex (Hessen, Germany) due to its geology (fractured crystalline basement) and petrology (Tromm granite). Considerable efforts and investigations were recently implemented to evaluate, whether this site is a suitable location for the realization of GeoLaB.

In the initial exploration stage, surface rock samples were collected in the Odenwald (Streitsdöll, Hammelbach and Ober-Mengelbach) area for mineral and petrological investigations. The sampling strategy aims for different structural contexts within the same lithology, e.g. a non-fractured granite, one located in the fault damage zone, and one located in the cataclastic core zone. The rock samples are macroscopically characterized by well-formed feldspar/plagioclase and mica (biotite/muscovite). Mineralogy and petrology are fundamental for investigating the composition and the occurrence of hydrothermal alteration. This influences rock properties such as porosity-permeability and also the response to applied stress.

A first set of eight samples was investigated by means of X-ray powder diffraction XRD (quantitative estimation of the mineral assemblage, rock classification), electron microprobe analyzer EMP (determination of the mineral geochemistry, hydrothermal alteration and microstructures) and X-ray fluorescence XRF (whole chemistry and trace elements). The granites/granodiorites are composed of quartz, plagioclase, felspar (andesine based on the Na-Ca geochemistry), and mica (biotite and muscovite). Apatite, magnetite, rutile and monazite were detected as accessories, thus enabling geochemical dating.

Three samples (Streitsdöll) show hydrothermal alterations in the form of kaolinite or clay phases with similar mineral chemistry Al2Si2O5(OH)4 at the plagioclase rims. Traces of metasomatic processes could be observed in the images acquired with the EMP. The quantitative mineral assemblage evaluation also indicated different types of plutonic rocks: granodiorite and granite based on the QAPF (Quartz, Alkali feldspar, Plagioclase, Feldspathoid (Foid)) diagram. A compositional variation with depth can be expected based on the mineral heterogeneity. This hypothesis will be verified by analyzing cores samples from exploration drillings planned for 2024.

Besides seismic and geophysical campaigns, additional fieldwork focusing on structural geology, rock sampling, and geomechanical experiments will be conducted to develop a baseline to scientifically assess whether the Odenwald site is a suitable location to build the GeoLaB.

 

Keywords:

underground laboratory, crystalline basement, fractured granite, mineral composition variation, hydrothermal alteration.

 

How to cite: Deon, F., Sass, I., Bossennec, C., Loges, A., Appelt, O., Seib, L., Milsch, H., and Zimmermann, G.: Mineralogical and petrological assessment of selected granites and granodiorites from the Odenwald area, Germany: a crucial step toward the site selection for the GeoLaB underground infrastructure?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6049, https://doi.org/10.5194/egusphere-egu24-6049, 2024.

EGU24-6759 | ECS | Posters on site | ERE2.6

Depth and time constraints on monzogranite emplacement and cooling in the Northern Tyrrhenian Sea: implications for the exhumation history of the Zuccale Fault (Island of Elba, Italy) 

Samuele Papeschi, Amy Moser, Marco Bonini, Chiara Del Ventisette, Riccardo Lanari, Matteo Lupi, and Domenico Montanari

Plutons in the Northern Apennines are generally thought to have been emplaced under low-angle normal faults (LANFs). However, the limited knowledge of their emplacement depth hinders a full understanding of their exhumation history and the tectonic setting in which they emplaced remains heavily debated. Indeed, granites in the Tuscan Archipelago are loosely constrained to P < 2 kbar, roughly corresponding to a maximum emplacement depth of 7-8 km. When considering that faults interpreted as LANFs in the area only show limited total displacements of a few km, the lack of constraints on the minimum depth of emplacement make it impossible to reconstruct the exhumation history of plutons in the area based on geochronology and low-temperature thermochronology only. Here we present the first precise constraints on the depth of magma emplacement on the Island of Elba, in the hinterland zone of the Northern Apennines. We investigated a spotted schist from the Terranera area of Eastern Elba, located in the footwall of the Zuccale Fault. The schist displays the garnet + cordierite metamorphic assemblage, which is very uncommon in the low-pressure Elban aureoles. We performed a detailed microstructural and petrographic study coupled with the analysis of mineral and bulk-rock chemistry through the Electron Microprobe and X-ray Fluorescence.

We modelled the sample with the phase equilibrium modelling approach using the PerpleX software, constraining the co-stability of garnet and cordierite to the narrow P interval of 0.3 – 1.2 kbar, corresponding to 1.1 – 4.4 km depth. Considering the limited horizontal throw of the Zuccale Fault, of just ~6 km and its current subhorizontal attitude, it is unrealistic that this fault contributed significantly to the exhumation of igneous rocks in eastern Elba. Rather, the estimated pressure is consistent with the thickness of the Northern Apennines orogenic nappe pile exposed on the island. Nevertheless, we acknowledge the need to obtain precise P constraints also from the Zuccale Fault footwall and we discuss P constraints derived from metamorphic assemblages therein.

We also provide the first U/Pb monazite ages of the young aureole which constrain peak metamorphic temperature to 6.7 ± 0.2 Ma. Considering the published radiometric constraints from the area, we suggest that Eastern Elba experienced a long-lived pluton-related thermal anomaly that persisted for ~0.8 – 1.2 Ma before cooling down to ‘normal’ upper crustal conditions, similar to the nearby, younger Larderello geothermal field.

This work was carried out as part of the MIGRATE project, funded by the SNFS.

How to cite: Papeschi, S., Moser, A., Bonini, M., Del Ventisette, C., Lanari, R., Lupi, M., and Montanari, D.: Depth and time constraints on monzogranite emplacement and cooling in the Northern Tyrrhenian Sea: implications for the exhumation history of the Zuccale Fault (Island of Elba, Italy), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6759, https://doi.org/10.5194/egusphere-egu24-6759, 2024.

EGU24-7014 | Orals | ERE2.6

Distribution of geothermal resources in New Zealand: insights from geophysics and numerical modelling 

Sophie Pearson-Grant, Edward Bertrand, Craig Miller, and Lucy Carson

New Zealand has abundant geothermal resources which produce ~20% of the country’s electricity. Most geothermal systems are located in the geologically complex rifting arc of the Taupō Volcanic Zone (TVZ), along the Australian/Pacific plate boundary. The TVZ is one of the most geothermally active regions on Earth, discharging ~4200 GW of heat through 23 high-temperature systems. Understanding the regional-scale factors influencing the locations of the geothermal systems is important for exploration and sustainable exploitation.

There are several intriguing correlations between TVZ geology and geothermal system locations. Over two-thirds of geothermal systems occur near inferred caldera margins. Many geothermal systems rise to the surface beneath topographic lows. Geothermal activity forms two NE-SW trending zones of low resistivity which are separated by the densely faulted and geothermally quiescent Taupo Fault Belt; most of the geothermal systems are not associated with any known major faults. We can gain new insights into these potential relationships by merging increasingly extensive geophysical and geological surveys of the central North Island of New Zealand into numerical flow models.

We created generalised numerical models of heat and fluid flow using TOUGH2 software to explore large-scale influences on geothermal circulation in the TVZ. Locations of over half the modelled geothermal systems can be broadly explained by the effects of topographic loading due to water table variations. Locations are further improved when topographic effects are combined with localised heat sources at depth inferred from magnetotelluric models. At three geothermal systems, influences such as more permeable volcano-sedimentary cover or a region of intense faulting that acts as a recharge zone for cold downwelling fluid also seem to be important. Three systems (Ohaaki, Te Kopia and Orakei Korako) cannot be explained with any of our models but are known to be in areas with significant local geological structures, making them interesting targets for future studies.

How to cite: Pearson-Grant, S., Bertrand, E., Miller, C., and Carson, L.: Distribution of geothermal resources in New Zealand: insights from geophysics and numerical modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7014, https://doi.org/10.5194/egusphere-egu24-7014, 2024.

EGU24-7029 | Posters on site | ERE2.6

Geothermal explorations of Paolai, Taiwan: integrated results from geological, geophysical, and geochemical surveys 

Shao-Yi Huang, Wen-Shan Chen, Hsien-Hsiang Hsieh, Wei-Hao Hsu, Hao Kuo-Chen, Ching-Wee Lin, Li-Hung Lin, Lun-Tao Tong, and Pei-Ling Wang

Taiwan, one of the most active orogens in the world, sits on the convergent plate boundary between the Luzon Arc of the Philippine Sea Plate and the continental margin of the Eurasian Plate. The Philippine Sea Plate continuously moves northwest and leads to the intense processes of mountain building. Consequently, the island presents a variety of tough landforms and bears high heat flows with potential for geothermal energy. The Single Service Window for Taiwan Geothermal Power estimated total geothermal potential around the island of Taiwan to be about 33.64 GW. The study area, Paolai Hot Spring, is known as one of the potential geothermal sites in Taiwan. The village situates upon the Laonung River, which drains across the low degree metamorphic strata, and is bounded by the Chaozhou Fault to the west. The Chaozhou Fault is an east-dipping thrust fault that brought up the low degree metamorphic argillite-to-slate strata over the sedimentary formations. To the east of the Chaozhou Fault, some researchers also suggested the occurrence of the Meilunshan Fault as orientation of strata and foliation appear to be different across the suspected fault. However, fault displacement is not evidenced in the field and the extent of the fault is still ambiguous. In this study, we conducted extensive geological, geophysical (including Magneto-Telluric, seismic, and gravity surveys), and geochemical surveys in this region to discuss the geothermal features across the Chaozhou Fault and the Meilungshan Fault, in terms of fluid, heat, fractures and the reservoir.

Two hydrological circulation models are justified here: 1) the single fault (the Chaozhou Fault solely) model and 2) the dual fault model. In the single fault model, the Chaozhou Fault serves as the controlling boundary with groundwater replenished from the eastern Backbone Range area. The deeply circulated fluids are heated and circulating along the highly ruptured, permeable zone within the Chaozhou Fault system. In the dual fault model, the Chaozhou and Meilunshan Faults divide the hydrological circulation into two systems. To the east of the Meilunshan Fault, groundwater is replenished from the Backbone Range area, circulating downward, heated, and migrates to the surface along the open fissures on the hanging wall of the Meilunshan Fault. To the west of the Meilunshan Fault, the circulation would be restricted by the two faults. Our field results concur occurrence of the Meilunshan Fault while the geophysical and geochemical data conformably suggest distinct characteristics of water and migration of fluids across the fault. Overall, our data show complex characteristics of multiple domains bounded by the two faults and suggest that the dual-fault model is more appropriate for further evaluations of geothermal potential. In addition, fractures are identified on the hanging wall of the Meilungshan Fault, which may serve as the near surface conduits of fluids. These areas hence have potential for shallow geothermal energy development because they both show evidence of deep reservoirs and shallow fractures. Test drilling and further investigation towards the complex structures in this region should be thoroughly considered in the future.

How to cite: Huang, S.-Y., Chen, W.-S., Hsieh, H.-H., Hsu, W.-H., Kuo-Chen, H., Lin, C.-W., Lin, L.-H., Tong, L.-T., and Wang, P.-L.: Geothermal explorations of Paolai, Taiwan: integrated results from geological, geophysical, and geochemical surveys, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7029, https://doi.org/10.5194/egusphere-egu24-7029, 2024.

EGU24-8140 | Posters on site | ERE2.6

Chemical and isotopic composition of steam from fumaroles in Hengill, SW Iceland 

Finnbogi Óskarsson and Egbert Jolie

The greater Hengill volcanic complex in SW Iceland is located on a triple junction between the rift zone of the Reykjanes peninsula, the Western rift zone of Iceland and the South Iceland seismic zone. It is divided into three volcanic systems; Hengill, Hrómundartindur and Grændalur, each of which has associated fissure swarms. The Hengill volcanic complex is host to several geothermal areas that are spread over most of its extent, with geothermal surface manifestations generally connected to the tectonic features.

Three of the geothermal systems within the youngest volcanic system (that of Mt. Hengill) have been exploited by Reykjavík Energy which runs two geothermal power plants: Hellisheiði and Nesjavellir. The power plants produce a total of 423 MWe which is sold on the national grid and 500 MWth in the form of heated groundwater for direct use in the capital area.

We report samples of steam, gas and condensate collected from 12 fumaroles in 11 geothermal subfields defined within the Mt. Hengill fissure swarm (Nesjavellir, Nesjalaugagil, Köldulaugagil, Hagavíkurlaugar, Fremstidalur, Miðdalur, Innstidalur, Sleggjubeinsdalur, Skarðsmýrarfjall, Skíðaskáli and Hverahlíð) in October 2019. The samples were analysed for concentrations of all major gases (CO2, H2S, H2, CH4, N2, O2), stable noble gases (He, Ne, Ar, Kr, Xe) as well as the 3He/4He isotopic ratio and the stable isotope ratios of carbon (δ13CCO2), hydrogen (δD) and oxygen (δ18O). This study is relevant for the chemical characterization of the key upflow zones in the volcano-tectonic system as well as the identification of promising target areas for the installation of advanced gas monitoring systems. Monitoring data can contribute to an improved understanding of processes in the subsurface related to volcanic and seismic activity, but also to geothermal reservoir operations.

The steam has generally rather low gas concentrations, with a total gas content of less than 500 mmol/kg steam for all samples except the few that had lost steam to condensation before sampling. All samples have CO2 as the most abundant gas followed H2S and H2. Gas geothermometry suggests temperatures ranging from about 250°C to more than 320°C. The stable water isotope values of the most powerful fumaroles are in good agreement with those obtained for well fluids, but the isotope values for steam from weaker fumaroles show signs of subsurface condensation. Carbon isotopes suggest that CO2 has a magmatic origin, as is most common for Icelandic high-temperature geothermal areas. Helium isotopes show clear mantle signatures with 3He/4He as high as 16 Ra but mixing with atmosphere is also observed.

How to cite: Óskarsson, F. and Jolie, E.: Chemical and isotopic composition of steam from fumaroles in Hengill, SW Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8140, https://doi.org/10.5194/egusphere-egu24-8140, 2024.

EGU24-8152 | ECS | Orals | ERE2.6

Mapping thermal conductivity in Ireland to determine geothermal potential 

Emma L. Chambers, Duygu Kiyan, Riccardo Pasquali, Javier Fullea, Pat Meere, Sergei Lebedev, Chris Bean, and Brian O'Reilly

High-quality maps of the geothermal gradient and temperature are essential when assessing the geothermal potential of a region. However, determining geothermal potential is a challenge when direct measurements of in situ temperature and thermal property information are sparse, as is the case in Ireland. In addition, individual geophysical methods are sensitive to a range of parameters, not solely temperature. We develop a novel approach to determine the geothermal gradient using a joint geophysical-petrological thermochemical inversion (Chambers et al. Tectonophysics (2023) & Fullea et al. GJI (2021)), which requires seismic surface wave data, thermal property data, and additional geophysical and petrophysical datasets. The multi-parameter models produced by the integrated inversions fit the surface-wave, heat flow and additional data, revealing the temperature, lithospheric structure and geothermal gradient within the crust and mantle.

Here we present the new methodology and resulting models of Ireland’s subsurface temperature with a focus on new thermal conductivity measurements and their impact on temperature. A new map of thermal conductivity (TC) for all of Ireland was generated using all existing measurements of thermal conductivity, in addition to 609 new measurements from the optical scanning technique and 86 using the Divided Bar Apparatus (DB) which we use in the inversion. Our new methodology produces results comparable to past temperature and geophysical measurements and models. Importantly, the maps are within error of direct borehole temperature measurements, providing confidence in the results. Lithospheric and crustal thickness play a key control on the temperature gradient with areas of thinner lithosphere resulting in elevated geotherms. In some locations, we observe geotherms elevated beyond expectations which result from high radiogenic heat production from granitic and muddy limestone rocks. This new methodology provides a robust workflow for determining the geothermal potential in areas with limited direct measurements. The final temperature model updates previous maps of Ireland and will be used for future geothermal exploration and utilisation.

How to cite: Chambers, E. L., Kiyan, D., Pasquali, R., Fullea, J., Meere, P., Lebedev, S., Bean, C., and O'Reilly, B.: Mapping thermal conductivity in Ireland to determine geothermal potential, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8152, https://doi.org/10.5194/egusphere-egu24-8152, 2024.

EGU24-8494 | ECS | Posters on site | ERE2.6

Gravimetric and magnetic 3D joint modelling of La Palma, Canary Islands, for geothermal resources exploration. 

María C. Romero-Toribio, Fátima Martín Hernández, Juanjo Ledo, Pilar Queralt Capdevila, Perla Piña-Varas, David Martínez van Dorth, Vicente Carlos Ruíz Martínez, Javier Pavón-Carrasco, Luca D'Auria, Nemesio Pérez, Javier Fullea, Ana Negredo, and María Luisa Osete

The energy supply of the Canary Islands currently depends on more than 95% of fossil fuel sources, with geothermal research constituting a strategic action. Geophysical monitoring is essential to understand subsurface processes and properties to significantly enhance the potential of geothermal energy development in La Palma. In the 90s and early 2000s, several geophysical surveys were conducted in the island, but data for each physical property were modelled separately. However, regional anomalies such as gravimetric and magnetic offer complementary information about target structures and therefore, can be advantageously modelled together to obtain more constrained and thus more reliable models. An intuitive and easily comprehensive 3D model is conceived to study La Palma thermal lithosphere.

Magnetic anomaly data are retrieved from the aeromagnetic flight carried out by the Instituto Geográfico Nacional (IGN) in 1993 (Socías & Mezcua, 1996). Bouguer anomaly data for this study are composed of those observed in 2005 and 2021, published in Montesino et al. (2023), and those acquired by the IGN levelling network in early 2000s. We processed the data using ZondGM3D modelling software.

As a part of our results, we aim to compare the 3D density and magnetization distribution models of La Palma after individual and joint data inversions. In addition, we will discuss and compare our results with Di Paolo et al. (2020) geothermal system revealed using magnetotellurics and the electrical resistivity model from Piña-Varas et al. (2023) volcanic monitoring, including other previous gravity and magnetic anomaly models from literature.

This study is part of the GEOTHERPAL project in which several Spanish institutions aim to perform a multidisciplinary and multiscale geophysical and geochemical imaging of La Palma Island geothermal system, essential to estimate its energy potential. More details are found at the web site of the project: http://pc213fis.fis.ucm.es/GEOTHERPAL/index.html

How to cite: Romero-Toribio, M. C., Martín Hernández, F., Ledo, J., Queralt Capdevila, P., Piña-Varas, P., Martínez van Dorth, D., Ruíz Martínez, V. C., Pavón-Carrasco, J., D'Auria, L., Pérez, N., Fullea, J., Negredo, A., and Osete, M. L.: Gravimetric and magnetic 3D joint modelling of La Palma, Canary Islands, for geothermal resources exploration., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8494, https://doi.org/10.5194/egusphere-egu24-8494, 2024.

Hot fluid-rock interactions in volcanic-hosted geothermal systems favour the presence of hydrothermal alteration patterns conforming the clay cap, dominated by argillic alteration, and the propylitic zone, currently related to the geothermal reservoir. Clay minerals are ubiquitous phases in these geothermal systems, being the reaction progress from trioctahedral smectite to chlorite, via chlorite/smectite (C/S), and dioctahedral smectite to illite, via illite to smectite (I/S), typical indicators of evolution from clay cap to reservoir conditions with increasing temperature. In fact, different geothermometers have been proposed using chlorite composition highlighting the relevance of clay minerals for a complete understanding of hydrothermal pathways in active geothermal systems.

Here, we analyse clay minerals (petrography, XRD, SEM-EDX and HR-TEM-EDX) from a 1000.87 m deep exploration drill core in the active Nevados de Chillán Geothemal System (NChGS) in Southern Volcanic Zone (central Chile). Lithologies are dominated by andesitic lavas and volcaniclastic breccias. Based on hydrothermal mineral assemblages, a transition from argillic to sub-propylitic (c. 350 m deep), beginning the propylitic alteration zone at 680 m deep has been defined. In situ temperature measurements during drilling achieve values up to 200°C at the bottom of the well. Geophysical and geochemical approach suggest a geothermal reservoir at c. 1200 m deep, with temperatures around 250°C, hosted in fractured granitoids.

XRD of clay minerals include C/S, corrensite, chlorite, I/S and illite, with a decrease of C/S and I/S with depth. Based on SEM morphologies and sizes, two types of chlorites have been defined: Chl-1, systematically present along all the core and paragenetic with quartz+albite+calcite, characterized by grain size (10-40 mm) and Chl-2, mostly observed as fine-grained flakes (average grain size ~4 mm), only identified in deeper samples, in association with laumontite+epidote±prehnite and rare Ca-garnet. SEM-EDX analyses in Chl-1 suggest an increase in Mg with depth, contrasting with the reverse observed pattern in Chl-2, which is Fe-richer compared with Chl-1. HR-TEM of selected samples at different depths confirms (1) the presence of the Fe-richest chlorites at the shallow levels and a general Mg increase with depth, and (2) the presence of C/S along the core. Cathelineau’s geothermometers using SEM-EDX data provides temperatures of 170-220°C for Chl-1 and 220-240°C for Chl-2, consistent with in situ measured temperatures. However, HR-TEM-EDX chlorite data with (K+Na+Ca)<0.1 apfu provide a rather dispersion in the Inoue et al. (2018) geothermometer, with a progressive T increase from the upper sample (275±48°C) to the deepest one (312±69°C).

The presence of different types of chlorites in the NChGS is interpreted as consequence of different alteration patterns. Chl-1 is associated with a previous regional event meanwhile Chl-2 would be formed during the geothermal alteration stage. HR-TEM data also highlight the disequilibrium existing during geothermal alteration event, probably because the high fluid/rock ratio and the short time for mineral precipitation. Under these disequilibrium conditions, the application of chlorite chemistry-based geothermometers must be only considered as indicator of temperature rather as a precise way to define the real reservoir conditions.

Acknowledgments: ANID-FONDECYT Project 1220729 and Andean Geothermal Center of Excellence (CEGA).

How to cite: Morata, D., Maza, S., Abad, I., Cuevas, C., and Arancibia, G.: Understanding hydrothermal alteration pathways in active geothermal systems: a look from clay mineralogy on the Chilean Andes Nevados de Chillán Geothermal System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9017, https://doi.org/10.5194/egusphere-egu24-9017, 2024.

EGU24-9278 | ECS | Orals | ERE2.6

Present geothermal field characteristics and its influencing factors in Xiong'an New Area  

Sasa Guo, Yue Cui, and Boning Tang

Xiong'an New Area is located in the northern of Jizhong Depression in Bohai Bay Basin, covered by three geothermal fields: Niutuozhen, Rongcheng, and Gaoyang. Clarifying the rock physical conditions and geothermal characteristics, combined with the elements of geothermal resource accumulation (heat source, channel, reservoir, caprock, fluid), plays an important role in understanding geothermal resources.Based on heat source research, this study analyzed the temperature measurement curves of 30 drilling wells and measured data of thermal conductivity and heat generation rate of 100 rocks to analyze the geothermal gradient and distribution of geothermal flow in Xiong'an New Area. The results showed that Xiong'an New Area has a high geothermal background, with geothermal flow ranging from 53.3mW · m-2 to 106.5mW · m-2, with an average value of 73mW · m-2. It is higher than the average heat flow value of 63.0 ± 24.2mW · m-2 in China Mainland, and belongs to high abnormal area. The geothermal gradient of caprocks is around 35 ℃/km, slightly higher than that of the Mesozoic and Cenozoic fault basins in Eastern China. Based on the geothermal field, combined with the characteristics of heat sources, reservoirs, and channels of deep geothermal resources, a genetic model of geothermal resources in Xiong'an New Area is established. It is considered that the reservoir-cap assemblages composed of the Cenozoic caprocks and the Proterozoic carbonate rocks in Xiong'an New Area, the alternating structural pattern of uplift and sag, and fluid activity affect the occurrence of deep geothermal resources. The geothermal resources are prone to enrichment in uplifted structures controlled by faults or in low uplifted Proterozoic thermal reservoirs. The high-value of geothermal flow, high permeability reservoirs, and regional continuous caprocks are favorable areas for geothermal development.

How to cite: Guo, S., Cui, Y., and Tang, B.: Present geothermal field characteristics and its influencing factors in Xiong'an New Area , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9278, https://doi.org/10.5194/egusphere-egu24-9278, 2024.

EGU24-9927 | ECS | Posters on site | ERE2.6

Geological risk analysis of geothermal developments in a sedimentary basin, Hungary 

Ábel Markó, Tamara Tóthi, Imre Szilágyi, and Judit Mádl-Szőnyi

In our research, we develop a novel methodology to evaluate the geological uncertainties of geothermal exploration in order to quantify them. The outcomes can be used as inputs when deciding on new geothermal investments. Adapted from the hydrocarbon industry probability of success is evaluated by estimating potential geological risk factors which can hinder geothermal production and reinjection, following the risk assessment scheme of petroleum play analysis.

As a case study in a clastic geological environment, we test the methodology on the Zala Basin, a sedimentary subbasin of the Pannonian Basin, Hungary. Here, the Neogene (so-called Pannonian) sediments form one of the principal thermal water-reservoirs. Although the preliminary geothermal potential of the Zala region (SW Hungary) is assessed to be good, there is a need for more thorough analysis before starting new developments. As an example, heterogeneity of the deltaic and fluvial deposits poses geological risk. In our case study, we consider the risk of insufficient temperature, the absence of the appropriate aquifer formations, the bad quality of the aquifer i.e., the unfavourable distribution of the high permeable sandstone bodies, the insufficient permeability and flow rate as well as the potential risk of unsuccessful reinjection. This is done by combining and evaluating datasets from well data (lithology, well logs, well tests) and 3D seismic measurements. The goal of the assessment is to decide whether a future geothermal system can provide sufficient capacity, in the current case, for industrial or agricultural heat utilisation.

The first author was supported, and the research was financed through the KDP-2021 Cooperative Doctoral Programme of the Ministry of Innovation and Technology (Hungary) from the source of the National Research, Development and Innovation Fund, grant number: KDP_2021_ELTE_C1789026. The study was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21- 2022-00014 project.

How to cite: Markó, Á., Tóthi, T., Szilágyi, I., and Mádl-Szőnyi, J.: Geological risk analysis of geothermal developments in a sedimentary basin, Hungary, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9927, https://doi.org/10.5194/egusphere-egu24-9927, 2024.

EGU24-10911 | Orals | ERE2.6

Fluid flow in the Nevados de Chillán Geothermal System as an example of fractured reservoir, Southern Andes 

Gloria Arancibia, Valentina Mura, Camila López-Contreras, Isa Oyarzo, John Browning, David Healy, Santiago Maza, and Diego Morata

Understanding the controls on crustal fluid-flow in geothermal fractured reservoirs is critical to assessing their occurrence and storage capacity. The Nevados de Chillán Geothermal System (NChGS), located in Southern Chilean Andes, is hosted in volcanic-volcaniclastic rocks and fractured granitoids. In this work, we present evidence of how regional to local fault and fracture networks control the location and size of the NChGS.

Fractures in crystalline rocks were analyzed in three sites: 1) Shangri-La diorite, 2) Las Trancas granodiorite and 3) Valle Hermoso hornfels. Linear scanlines have a total cumulative length of 130 meters, in which >1000 fractures were measured. Results show preferential fracture orientations of N60E, N30E, and N45E for the three sites, respectively. Minor families of fractures in NNW and NW directions are also observed. The intensity of fractures (i.e. number of fractures/scanline length) is ~5m-1 at Shangri-La and exhibits minimum and maximum values between 6-13m-1 at Las Trancas, and between 8-13m-1 at Valle Hermoso. Variability in fracture intensity relates to profile orientation, presence of localized shear zones or distance from the geothermal system. These outcrop-scale structures are consistent with regional geometric arrangement and kinematics of major faults.

A fourth site was analyzed in the Las Termas-Olla de Mote area. Here, Miocene volcanic and volcaniclastic rocks present an intense argillic alteration in an area ca. 1 km2. Numerous surface geothermal manifestations, such as fumaroles, hot springs, mud pools, mud volcanoes, and heated soils, can be observed. Using a Hanna HI 98509 thermocouple and Fluke TiS45 infrared camera, surface temperatures between 13°C and 95°C were measured. In this site, 85 fractures were measured in a 3-meter-long scanline in a localized cataclastic shear zone. The fracture alignment is essentially isotropic with an intensity of ~28m-1. We noted a hydrothermal alteration pattern associated with centimetric to metric fault planes and fault zones. X-Ray Diffraction on clay minerals related to these fault-controlled alteration zones shows high-crystalline illite (Kübler index as low as 0.096) and kaolinite (Aparicio-Galan-Ferrer index as high as 1.115).

Numerical modeling, considering structural, hydrothermal and temperature data, was performed with COMSOL Multiphysics, which allowed us to demonstrate the control of fractures in the development of a crystalline rock hosted geothermal reservoir. The simulated reservoir isothermal pattern can be reproduced consistently with our conceptual geological model after 15 ka.

These combined results evidence the first order structural control on the formation of the NChGS. Intersection of regional fault/fracture systems and local dilation areas are the main controls that permit the formation and growth of the active geothermal system. Moreover, the high crystallinity fault-related illite and kaolinite confirms that fluid-flow is mainly controlled by secondary structural permeability. Finally, the surface temperature data, coupled with thermal numerical modelling, allow us to establish a comprehensive theoretical model for the active NChGS relevant for sustainable exploitation.

This work is a contribution to the ANID-FONDECYT Project 1220729 and Andean Geothermal Center of Excellence (CEGA). Valentina Mura thanks to ANID -Beca Doctorado Nacional 21210890. 

How to cite: Arancibia, G., Mura, V., López-Contreras, C., Oyarzo, I., Browning, J., Healy, D., Maza, S., and Morata, D.: Fluid flow in the Nevados de Chillán Geothermal System as an example of fractured reservoir, Southern Andes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10911, https://doi.org/10.5194/egusphere-egu24-10911, 2024.

EGU24-11626 | Posters on site | ERE2.6

Uncovering Lāna’i's hidden heat: geophysical insights on the subsurface hydrothermal activity of this Hawaiian island  

Xavier Bolós, Nicole Lautze, Mario Boijseauneau, and Mattox Telwar

The Hawaiian Islands, characterized by volcanic activity and complex hydrogeological systems, encounter energy challenges due to reliance on imported fossil fuels. Therefore, exploring geothermal sources is crucial for sustainable development, given the islands' isolation. Simultaneously, understanding freshwater reservoirs is vital for sustainable water resource management. This multidisciplinary study on Lāna’i Island integrates geophysical, groundwater, and mineralogical data, unveiling insights into concealed deep hydrothermal activity and its heat source. Correlations observed in newly acquired self-potential (SP) data combined with earlier gravity and magnetotellurics (MT) data reveal the presence of a hydrothermal upflow, perhaps originating from deep magma reservoirs beneath the Pālāwai caldera. The concealed hydrothermal system emerges as a potential geothermal resource at >2 km depth, requiring further deep drilling research to confirm its presence. In addition, XRD analysis reveals varying degrees of hydrothermal alteration, indicating high temperatures during fluid-rock interactions. The alignment of surface alteration with current upflow zones suggests an active hydrothermal system persists in the caldera faults since the shield-building stage, which causes warm brackish water within the Pālāwai basin. This prompts a discussion about the possible presence of a geothermal resource. This subject has been under investigation for the past seven years as part of the Hawaii Play Fairway project. The impact of hydrothermal activity appears limited to the Pālāwai caldera and the Canyon zone, contrasting with the Munro Trail ridge area, which serves as an independent freshwater source with impounded aquifers. Understanding this convergence of geothermal investigation and freshwater reservoir analysis holds significant importance for fostering sustainability in the Hawaiian archipelago.

How to cite: Bolós, X., Lautze, N., Boijseauneau, M., and Telwar, M.: Uncovering Lāna’i's hidden heat: geophysical insights on the subsurface hydrothermal activity of this Hawaiian island , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11626, https://doi.org/10.5194/egusphere-egu24-11626, 2024.

EGU24-11688 | Posters on site | ERE2.6

Morphological analysis and river inversion as a proxy to constraint upper crustal magmatic pluton emplacements: evidence from the Larderello-Travale Geothermal System, northern Apennines.  

Domenico Montanari, Riccardo Lanari, Marco Marco, Samuele Papeschi, Chiara Del Ventisette, and Matteo Lupi

Geomorphological techniques are used worldwide to explore how the topography responds to surface, crustal and mantle processes. This is the case for the recent developed river dynamic model inversion, that promises to return time vs uplift rate histories required to achieve the modern fluvial configurations. In the framework of the ‘Migrate Project’, a multidisciplinary project combining geology, seismology and machine learning financially supported by the SNSF, we test a novel method of rivers inversion to constrain the surface vertical movements caused by the emplacement of middle-shallow crustal magmatic pluton. We selected, as case study, the Larderello-Travale Geothermal System (LTGS), in the northern Italian Apennines, where multiple magmatic bodies intruded since the late Pliocene causing a large-wavelength surface uplift of at least 600 meters. However, since none of the LTGS plutons reach the surface, their spatial distribution is only constrained by exploration wells or geophysical investigations. Our work aims to: (1) quantify the surface response to pluton emplacement and (2) identify intrusions not yet documented in the area.

We modelled 31 river basins draining the LTGS and surrounding regions. For all catchments, the available ages of plutons constrained by wells, spatially correlate with the local peaks of increasing uplift rates (> 0.2 mm/y). We document a diffuse regional uplift during middle/late Pliocene, likely a consequence of the first magmatic pluton emplacement, followed by a continuous uplift throughout Quaternary times. However, during this time interval, the uplift style changed to confined pulses, which we interpret as locally emplaced magmatic batches. In addition, uplift rates decreased systematically from 0.6 Ma to present, which suggests a potential reduction on the topographic response to magma emplacement, even if the thermal anomaly is still quite evident. This work confirms that plutons provide a topographic swell, and we suggest that our approach could be used to locate undocumented plutons, leading to new potential strategies for geothermal exploration.

How to cite: Montanari, D., Lanari, R., Marco, M., Papeschi, S., Del Ventisette, C., and Lupi, M.: Morphological analysis and river inversion as a proxy to constraint upper crustal magmatic pluton emplacements: evidence from the Larderello-Travale Geothermal System, northern Apennines. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11688, https://doi.org/10.5194/egusphere-egu24-11688, 2024.

EGU24-12047 | Posters on site | ERE2.6

Diffuse He and H2 degassing survey for geothermal exploration at La Palma, Canary Islands 

Gladys V. Melián, Matteo Furlan, Malte Seefeld, Alba Martin-Lorenzo, Ana Gironés, Nemesio M. Pérez, Fátima Rodríguez, María Asensio-Ramos, Eleazar Padrón, Pedro A. Hernández, Germán D. Padilla, Sttefany Cartaya, and Mónica Arencibia

During geothermal exploration, the geochemical methods are extensively used and play a major role in both exploration and exploitation phases. Discovery of new geothermal systems at those areas where the resources are either hidden or lie at great depths, the geochemical methods for geothermal exploration must include soil gas surveys, based on the detection of anomalously high concentrations of some hydrothermal gases in the soil atmosphere. We report herein the results of an intensive soil gas study, focused on non-reactive and/or highly mobile gases such as helium (He) and hydrogen (H2), in Cumbre Vieja volcano, the volcanically ac tive part of La Palma island (Canary Islands, Spain). He has unique characteristics as a geochemical tracer: it is chemically inert and radioactively stable, non-biogenic, highly mobile and relatively insoluble in water. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas.

A detailed geochemical survey was carried out in an area of 25 km2 at the western side of La Palma. A total of 766 sites were sampled at 40 cm depth using a metallic probe with 60 cc hypodermic syringes and stored in 10 cc glass vials for later laboratory analyses. Spatial distribution maps of diffuse He and H2 emission were constructed to study the presence of enhanced vertical permeability areas related to high temperature hydrothermal activity at depth. As a result, the main He emission anomalies show different size well-defined concentric-shape structures, distributed along a west to east main direction. On the other hand, H2 highest fluxes are slightly more dispersed in different areas, although some of the main ones are coincident with the distribution of the well-known anomalous volcanic CO2 active diffuse degassing in Puerto Naos and La Bombilla villages. Soil He and H2 surveys have demonstrated to provide meaningful insights of areas that could be acting as preferential zones of vertical permeability that allow deep source gases migration to surface and, therefore, of potential geothermal system structures.

How to cite: Melián, G. V., Furlan, M., Seefeld, M., Martin-Lorenzo, A., Gironés, A., Pérez, N. M., Rodríguez, F., Asensio-Ramos, M., Padrón, E., Hernández, P. A., Padilla, G. D., Cartaya, S., and Arencibia, M.: Diffuse He and H2 degassing survey for geothermal exploration at La Palma, Canary Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12047, https://doi.org/10.5194/egusphere-egu24-12047, 2024.

The increasing demand for renewable energy highlights a compelling necessity to exploit and use of geothermal energy in Germany. A notable research initiative in this regard is the WärmeGut project, funded by the Federal Ministry of energy and climate protection (BMWK) and aims on reconnaissance and re-evaluation of subsurface data to extend the geothermal information system of Germany, GeotIS. Specifically, Tertiary successions are hitherto underexplored because the focus of past geothermal exploration went to deeper levels below the Tertiary. One of the research goals places therefore significant emphasis on evaluating the potential of shallow to medium-depth geothermal resources of the Tertiary sandstones in the North German Basin (NGB).

In this study, we conducted a high-resolution sequence stratigraphy applied to reservoir characterization of the Tertiary sandstones in the NGB. Sequence stratigraphy holds considerable importance in geological reconstruction, significantly enhancing the precision of predictions within the domain of underground geological exploration. This aspect has received comparatively less attention, especially in the context of the Tertiary interval in the NGB. We conducted analysis of well logs from 15 sites, which included gamma ray, density, sonic, resistivity and photoelectric factor data. We investigate the temporal and spatial distribution of sandstone facies within the sequence stratigraphic framework of the Tertiary sequence in the NGB Basin. Primarily, the focus of the study revolves around the examination of four sandstone units located in the uppermost portion of the Lower Eocene, the Middle Eocene (Brüsselsand), the lower Oligocene (Neuegammer Sand), and the Upper Miocene.

The primary findings suggest that sedimentary sequences in the NGB during the Tertiary period display repetitive episodes of progradation, interspersed with periods of flooding on the depositional platform. These dynamics are notably marked by a significant increase in gamma-ray signals, which record maximum marine flooding over the basin margin. This observation underlines the cyclical nature of sedimentary processes during the Tertiary in the NGB. Each sequence is characterized by progradational and retrogradational facies, with shale predominating during the transgression phase, followed by an alternation of sand and shale. Sand and silt content gradually increases during the regression phase, with four major sandstone layers occurring at the maximum regression phases. On a spatial scale, the increasing shale content within alternating sand and shale intervals indicates the accommodation depth of the depositional system.

Additionally, we have conducted a petrophysical analysis to evaluate the quality of sandstones as a geothermal reservoir. Obtained results suggest that the porosity exceeds 5%, with variations influenced by the thickness, shale content, and depth of the respective sandstone units. However, both the thickness and petrophysical characteristics of the sandstone units demonstrate variations across different spatial scales within the NGB. The results indicate a general applicability of Tertiary sandstones for hydrothermal direct use in medium –depth level, but more detailed well log analysis is required to delineate shale successions. The study helps assess the geothermal potential of Tertiary sandstones in the NGB.

How to cite: Sardar Abadi, M., Erb, M., and Moeck, I. S.: WärmeGut: Stratigraphic Significance of Tertiary Sandstones as Potential Shallow to Medium-Depth Geothermal Reservoirs in the North German Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12217, https://doi.org/10.5194/egusphere-egu24-12217, 2024.

EGU24-12301 | ECS | Orals | ERE2.6

Soil gas CO2 concentration, isotopic ratio and efflux measurements for geothermal exploration in La Palma, Canary Islands. 

Alba Martín Lorenzo, Karen Copete-Murillo, Ángel Reyes, Ana Gironés, Gladys V. Melián, María Asensio-Ramos, Fátima Rodríguez, Eleazar Padrón, Germán D. Padilla, Pedro A. Hernández, and Nemesio M. Pérez

Located in the northwest of Canary Islands, La Palma is one of the most volcanically active islands in the archipelago. The island experienced a volcanic eruption from 19 September to 13 December 2021, which had significant social, economic, and scientific impacts. This event serves as a reminder of the island's potential as a host for geothermal resources. Therefore, geochemical prospection of soil gases at Cumbre Vieja can provide valuable information for investigating the presence of permeable areas and potential upflow for degassing of geothermal systems at depth. This study was carried out between July and September 2023 and presents the results of a soil gas study located southwest of the 2021 lava flow. The survey aimed to identify permeable areas by conducting in-situ measurements of diffuse CO2 emissions and sampling and analyzing CO2 concentration and isotopic composition (δ13C-CO2). A total of 766 sampling sites were selected over an area of approximately 25 km2, with an average distance of 100 m between sites. Soil CO2 concentrations ranged from typical atmospheric values (≈ 400 ppm) up to 40,000 ppm. The average CO2 concentration measured was 1,700 ppm. The δ13C-CO2 isotopic composition revealed the presence of three distinct end-members: biogenic, atmospheric and deep-seated CO2, defined by isotopic compositions of 25‰>δ13C-CO2>-15‰, -8‰ and 2.1‰>δ13C-CO2>-8‰ and CO2 concentrations of 100%, 0.04% and 100%, respectively. Results show that, with a mean of -13.7‰, a minimum of -28.9‰ and a maximum of -4.8‰, CO2 at most sampling sites is composed of various mixtures of atmospheric and biogenic CO2, with some contributions from deep-seated CO2. The accumulation chamber method was used to measure soil CO2 efflux at each sampling site using a portable non-dispersive CO2 sensor, model LICOR-Li-820. The measured CO2 efflux values ranged from non-detectable to 160.3 g·m-2·d-1, with an average value of 4.7 g·m-2·d-1. For the estimation of the total diffuse CO2 emission from the study area, we calculated the average of 100 sequential Gaussian simulations. This gave a value of 100.8 ± 2.8 t·d-1, corresponding to a standardized emission rate of 4.1 t·km-2-d-1. The results show a significant correlation between the distribution of 222Rn gas activity anomalies and the highest CO2 efflux values in the eastern part of the study area. Soil gas measurements of CO2 concentration, isotopic ratio and efflux are a valuable and non-invasive technique for surface exploration, helping to define permeable areas and potential upflow zones of potential geothermal system structures and enabling an efficient subsequent subsurface exploration phase.

How to cite: Martín Lorenzo, A., Copete-Murillo, K., Reyes, Á., Gironés, A., Melián, G. V., Asensio-Ramos, M., Rodríguez, F., Padrón, E., Padilla, G. D., Hernández, P. A., and Pérez, N. M.: Soil gas CO2 concentration, isotopic ratio and efflux measurements for geothermal exploration in La Palma, Canary Islands., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12301, https://doi.org/10.5194/egusphere-egu24-12301, 2024.

EGU24-12590 | Posters on site | ERE2.6

InGEO: GEOthermal resources and reserves potential assessment for the decarbonisation of power/thermal sectors 

Gianluca Gola, Magdala Tesauro, Antonio Gargaro, and Adele Manzella

Geothermal energy, as a renewable and green source for power generation and district heating and/or cooling, is available all year round, at all times of the day, and has great potential for development in any country. However, the exploitation of deep geothermal resources is only possible after detailed characterization of the potential reservoir. In fact, knowledge of the thermo-physical properties of the underground reservoir is crucial for generate a forecast  estimation of the geothermal reservoir thermodynamic behavior, as well as for mining risk reduction and optimization of the sound design of geothermal energy production systems.

The InGEO project (Innovation in GEOthermal resources and reserves potential assessment for the decarbonisation of power/thermal sectors) aims to develop an innovative exploration workflow integrating geophysical data and other direct and indirect information, organized to make available a sort of decision support system of geothermal projects. It consists of the reconstruction of the crustal and subcrustal structures by joint analyses and interpretations of available and acquired geological and geophysical data (e.g., those provided by mechanical and thermal rock samples laboratory analyses, seismic and gravity anomalies), taking advantage of the different sensitivity that geophysical methods have on physical rock's parameters (temperature and composition). The results will be the input for the geothermal model that will quantify the deep geothermal resource potential of the area. The designed workflow will be tested in a case study area and partially calibrated with developed (hydrothermal) available data. The methodological approach proposed by InGEO is also expected to define the potential local use of geothermal systems by Deep Closed-loop Borehole Heat Exchangers (DBHE) for power generation, district heating and/or cooling. The InGEO results will contribute to the second mission of PNRR “MISSION 2: GREEN REVOLUTION AND ECOLOGICAL TRANSITION”, by expanding the business planning of deep geothermal resource use in Italy.

The test area, chosen because it is considered particularly representative of the project topic and of potential reproducibility, includes the sector of the Northern Apennine buried structures, belonging to the Romagna and Ferrara Folds (RFF). The RFF area has been the target of previous geothermal studies highlighting relatively low geothermal gradients within the deep carbonate units (on average 14 °C/km) and more significant thermal gradients (on average 53 °C/km) in the overlying impermeable formations [1-2]. This feature in temperature distribution with depth is clear evidence for fluid thermal convection occurring in the deep-seated carbonate units of Mesozoic age, which constitutes the local geothermal reservoir.

[1] Pasquale et al., 2013. Evidence for thermal convection in the deep carbonate aquifer of the eastern sector of the Po Plain Italy. Tectonophysics, 594, 1-12.

[2] Pasquale et al., 2014. Heat flow and geothermal resources in northern Italy. Ren. Sust. Energy Rev., 36, 277-285.

How to cite: Gola, G., Tesauro, M., Gargaro, A., and Manzella, A.: InGEO: GEOthermal resources and reserves potential assessment for the decarbonisation of power/thermal sectors, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12590, https://doi.org/10.5194/egusphere-egu24-12590, 2024.

EGU24-12849 | Posters on site | ERE2.6

Sustainable geothermal energy for two Southern Italy regions: geophysical resource evaluation and public awareness  

Ortensia Amoroso, Valeria Giampaolo, Marianna Balasco, Massimo Blasone, Davide Bubbico, Paolo Capuano, Gregory De Martino, Maria Vittoria Gargiulo, Ferdinando Napolitano, Angela Perrone, Serena Panebianco, Raffaella Russo, Vincenzo Serlenga, and Tony Alfredo Stabile

This work shows the first results of activities carried out in the framework of project TOGETHER - Sustainable geothermal energy for two Southern Italy regions: geophysical resource evaluation and public awareness financed by European Union – Next Generation EU (PRIN-PNRR 2022, CUP D53D23022850001).

The deployment and sustainable use of Italy's geothermal resources could represent a key asset to increase renewable energy production and reduce greenhouse gas emissions in the years ahead. Within this context, there is an obvious need for programs to improve subsurface geothermal resource extraction while maintaining environmental sustainability.

Assessing the potential exploitation requires knowing the type of geothermal system, the likely temperature and characteristics of the reservoir rocks and fluids. We propose a novel geophysical multi-messenger approach, which provides unique and useful insights into the features and activities of examined geothermal reservoirs. These findings stem from the complementary information carried by subsoil geophysical parameters such as electrical resistivity and elastic/anelastic characteristics related to fluid presence. The proposed method will be tested in two test regions in Southern Italy that are appropriate for low to medium-enthalpy geothermal extraction: Contursi Terme and Tramutola. Contursi Terme is one of the most appreciated thermal sites in the whole Campania region. Here, 77 springs with temperatures ranging from 21°C to 30°C are present; furthermore, 72 shallower and deeper wells for the pumping of hot waters with temperatures ranging from 38°C to 43°C are used for balneotherapy. The Tramutola test site is located on the western side of the Agri Valley (Basilicata region) which hosts the largest onshore hydrocarbon reservoir of Western Europe. During the drilling of the "Tramutola2" well (404.4 m) in 1936, a significant volume of sulphureous hypothermal water (28 °C with a flow rate of 10 l/s) with accompanying gases (mostly CH4 and CO2) was discovered.

At the same time, TOGETHER project aims to develop and apply communication methodologies devoted to increasing the acceptance of the exploitation of geothermal energy. This objective will be accomplished by actively engaging local communities and younger generations, who will serve as the foundation for scientific education, social interaction, and constructive debate.

How to cite: Amoroso, O., Giampaolo, V., Balasco, M., Blasone, M., Bubbico, D., Capuano, P., De Martino, G., Gargiulo, M. V., Napolitano, F., Perrone, A., Panebianco, S., Russo, R., Serlenga, V., and Stabile, T. A.: Sustainable geothermal energy for two Southern Italy regions: geophysical resource evaluation and public awareness , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12849, https://doi.org/10.5194/egusphere-egu24-12849, 2024.

EGU24-13959 | ECS | Posters on site | ERE2.6

The Geothermal Conceptual Model and Resource Assessment of the Shamao Mountain Geothermal Potential Area in the Tatun Volcano Group (TVG), Taiwan 

Gi-Yi Huang, Bieng-Zih Hsieh, Kenn-Ming Yang, Tien-Kai Tang, Mu-Hsun He, Cheng-Yueh Wu, Guo-Teng Hong, and Wan-Chung Lu

Renewable energy is a sustainable and clean with no (or very few) carbon dioxide emissions. Geothermal energy is a renewable energy, it uses the geo-heat from the Earth and can generate a base-load electricity. Taiwan aims to achieve zero-emission by 2050. For this target, geothermal energy plays a crucial role to help Taiwan make the goal of zero-emission electricity possible.

Taiwan, located at the Pacific Ring of Fire, has abundant geothermal resources. The estimated conventional geothermal potential in Taiwan is about 989 MW. In which, The Tatun Volcano Group (TVG) in northern Taiwan has the most conventional geothermal potential of over 500 MW. The investigation and development of geothermal resources in the Tatun Volcano Group is important for the development of Taiwan's geothermal energy.

The purpose of this study is to conduct a geothermal resource investigation in the Mt. Shamao area a located in the Tatun Volcano Group in order to apply the information for the next-step exploration well drilling. This research establishes a three-dimensional geothermal conceptual model by geothermal geological surveys and estimate the geothermal resources based on the developed conceptual model.

 

This study primarily involves initiating field geological investigations to explore the lithology of the geothermal reservoir and potential structures and fractures in the Mt. Shamao area. Based on the rock types recorded during field geological investigations and subsurface geological interpretations, we aim to establish a geothermal conceptual model for the region. Additionally, a three-dimensional geothermal geological model will be developed for heat storage assessment.

Field investigation is used in this study to explore the lithology of the targeted geothermal reservoir as well as the potential structures and fractures in the Mt. Shamao area. By combining the findings from the field investigation and the subsurface geological interpretations from the neighboring existed deep wells, the geothermal conceptual model is established. All information is integrated in a 3-D model built in the GOCAD simulator. Based on this 3-D model, the geothermal resources is estimated by a numerical simulator, CMG STARS.

 

The geological model of Mt. Shamao area is built  based on  previously and newly reconstructed geological profiles, lithological well logs, DEM data, regional fracture and structural lineament data, and lithofacies descriptions in the field. This area is characterized by numerous high-angle faults, which may serve as effective geothermal conduits. The geological model shows andesite of about 750 meters overlying sandstone-rich formations in the Mt. Shamao area. From the temperature records of nearby deep wells, the highest temperature is in the andesite reaching 174°C, and the maximum temperature is 240°C found in the sandstone formation.

Based on the constructed geological model and the temperature log of existed wells, the natural state model for the Mt. Shamao area is established from the numerical simulation method. The storage heat capacity is estimated for the area of about 12 square kilometers with the thickness of 5 km. By considering the development period of 20 years, the estimated power potential of Mt. Shamao area is over 200 MW from the volumetric method.

How to cite: Huang, G.-Y., Hsieh, B.-Z., Yang, K.-M., Tang, T.-K., He, M.-H., Wu, C.-Y., Hong, G.-T., and Lu, W.-C.: The Geothermal Conceptual Model and Resource Assessment of the Shamao Mountain Geothermal Potential Area in the Tatun Volcano Group (TVG), Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13959, https://doi.org/10.5194/egusphere-egu24-13959, 2024.

EGU24-14595 | ECS | Orals | ERE2.6

Investigating the Heat Source of Yangbajing Geothermal Field, South Tibet, with Magnetotelluric Data 

Lulu Lei, Sheng Jin, Hao Dong, Wenbo Wei, Gaofeng Ye, and Letian Zhang

The Yangbajing geothermal field, located in the south part of the Tibetan plateau is the largest high-temperature geothermal system of the whole plateau. Numerous hydrological, geological, and geothermal studies have been conducted to gain insights into the heat source of the geothermal system. Geothermal studies show that heat flow in this area is extremely high. However, heat flow contributed by the crustal radiogenic heating together with mantle heating still can not explain the anomalously high heat flow (~116 mW/m2) here. In this study, we use the high-resolution 3D electrical resistivity models, generated from magnetotelluric data in the Yangbajing region of southern Tibet, that image zones of enhanced conductivity in the middle crust. Such features may relate to partial melts (or magma chambers) with a melt fraction of more than 19%. Here, with the help of other available data, primarily hydrothermal and geochemical data, we estimated the heat flow generated by the partial melts in this area. Furthermore, we performed a set of simulations to reproduce the thermal evolution of the magma chambers in this region. our results indicate that the magma chambers below the study region may provide sufficient heat flow to fill the relatively large heat flow gap (~20.25 mW/m2 ), apart from the mantle heat conduction and radiogenic heating for the geothermal system. In addition, the thermal evolution simulations show that the magma chambers beneath the Yangbajing geothermal system may remain relatively warm, after the long cooling procedure. Our results highlight the possible contribution of the magmatic heat generation to the Yangbajing geothermal system, and reveal that crust contributes a significant proportion of the total surface heat flow (~70.75 mW/m2) in the Yangbajing geothermal field, which is much higher when compared with the typical rift basins in China.

How to cite: Lei, L., Jin, S., Dong, H., Wei, W., Ye, G., and Zhang, L.: Investigating the Heat Source of Yangbajing Geothermal Field, South Tibet, with Magnetotelluric Data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14595, https://doi.org/10.5194/egusphere-egu24-14595, 2024.

EGU24-15055 | ECS | Orals | ERE2.6

The ArtemIS project: Assessment for medium-depth geothermal energy utilization in Germany  

Leandra Weydt, Jeroen van der Vaart, and Ingo Sass

To date, the majority of geothermal projects in Germany have focused on deep geothermal systems, while resources at intermediate depths have been little explored. However, intermediate-depth geothermal systems have a high potential for heat generation, even in areas previously considered less favourable for geothermal use, and could make a significant contribution to Germany's heat supply. In order to accelerate the heat transition and to become independent of fossil fuels, the ArtemIS project aims to assess the medium-depth geothermal systems in Germany, covering all types of geological plays and providing regionalised information for different geothermal applications. To this end, profile texts will be developed containing all relevant subsurface information required for preliminary geothermal assessments, such as geological descriptions of potential geothermal reservoirs, reservoir thickness, hydraulic and thermal rock properties, and fluid chemistry. In addition, static 3D geological models are created as the basis for 2D and 3D numerical reservoir models to simulate the regional heat potential and different geothermal exploitation scenarios, including the performance of hydrothermal doublets. Machine learning algorithms will be applied to speed up the extraction and analysis of well data and to improve reservoir evaluation and economic forecasting, particularly in areas of low data density. The results will be integrated into the publicly available web platform "Geothermal Information System - GeotIS", which will provide general information, data and modelling results in a user-friendly way for non-professionals such as local communities and municipal energy suppliers. Here we present the current status and first results of the ArtemIS project.

How to cite: Weydt, L., van der Vaart, J., and Sass, I.: The ArtemIS project: Assessment for medium-depth geothermal energy utilization in Germany , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15055, https://doi.org/10.5194/egusphere-egu24-15055, 2024.

EGU24-15521 | Orals | ERE2.6

The Emotion Project:  improvement of the geochemical knowledge on geothermal manifestations in Italy 

Barbara Cantucci Marini, Monia Procesi, Franco Tassi, Carlo Cardellini, Carmine Apollaro, Dmitri Rouwet, Francesca Zorzi, Giovanni Vespasiano, Emanuela Bagnato, Giancarlo Tamburello, Stefania Venturi, Daniele Cinti, and Donato Belmonte

Energy request from renewable sources is increasing due to high energy demand and the need of a more sustainable use of the resources. Among renewable sources, geothermal energy represents a powerful tool to reduce the energy dependence on fossils contributing to reducing the impact of climate change.

Despite its high potential, geothermal energy has historically had a limited role in Italy, confined to the well known Tuscany areas, although it could have a more widespread exploitation satisfying local energy demands through both direct and indirect uses.

The Emotion Project (GeochEMical characterization of geOThermal manifestations in Italy and development of the natIONal geothermal fluid web portal) is a three-year broad-scope project (2023-2025) funded by the Italian Ministry of University and Research in the framework of ten-year INGV PIANETA DINAMICO Research-Program (https://progetti.ingv.it/it/emotion).

The ambition of EMOTION project is to accelerate the geothermal exploration for low, medium and high temperature (enthalpy) resources by a detailed geochemical characterization of the manifestations of geothermal interest located in central-northern Italy and to develop a solid and public web portal of all Italian geothermal manifestations, including those already studied in the central-southern part of the country (Vigor Project).

Here we present first year results obtained by a detailed critical review of available geochemical information on thermal springs, mineral waters and gas emissions. These data represent the starting point to identify interesting and data-missing areas to be further investigated by new geochemical campaigns planned for 2024. Eleven Italian Regions were investigated (Tuscany, Umbria, Marches, Emilia Romagna, Liguria, Piedmont, Aosta Valley, Lombardy, Trentino Alto Adige, Veneto and Friuli Venezia Giulia) by a research team belonging to INGV, University of Florence, Perugia, Genoa and Calabria. The review data were collected from scientific papers, unpublished theses, regional datasets, reports and well logs (e.g., AGIP), other web portals and unpublished data.

More than 4000 fluid manifestation information, among which thermal and cold springs, wells, bubbling polls, dry vents and fumaroles were collected and organized in a database, as homogeneous as possible. The database includes geographical data, geochemical analysis of major, minor, trace ad isotopic species, physics-chemical parameters and information on water table level and flow rate.

To get hints on reservoir temperatures, chemical-physical processes ruling fluid circulation and to discriminate manifestations of geothermal interest from the others, a selection was made considering specific criteria, proposing also a first approach to standardizing geochemical data, potentially useful in the framework of opening and sharing scientific data.

How to cite: Cantucci Marini, B., Procesi, M., Tassi, F., Cardellini, C., Apollaro, C., Rouwet, D., Zorzi, F., Vespasiano, G., Bagnato, E., Tamburello, G., Venturi, S., Cinti, D., and Belmonte, D.: The Emotion Project:  improvement of the geochemical knowledge on geothermal manifestations in Italy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15521, https://doi.org/10.5194/egusphere-egu24-15521, 2024.

EGU24-16021 | Orals | ERE2.6

Geothermal prospecting by ground radon and radon/thoron ratio measurements at La Palma, Canary Islands 

Ana Gironés, Anna Valls, Maisie Thompson, Alba Martín, Nemesio M. Pérez, Gladys V. Melián, Eleazar Padrón, Germán D. Padilla, Pedro A. Hernández, María Asensio-Ramos, and Fátima Rodríguez

Geothermal energy has reached the front line on renewable resources assessment in recent years, especially in active volcanic areas such as the Canary Islands (Spain), and precisely in La Palma island, where a recent volcanic eruption occurred in 2021, representing a unique opportunity to carry out in situ exploration. Cost-effective geochemical surveys, like soil radon (222Rn) and thoron (220Rn) gases activities measurements, have demonstrated to provide relevant insights as part of surface geothermal exploration, helping to identify permeable areas and potential up-flow zones and, therefore, defining potential geothermal systems boundaries. Both radon (222Rn) and thoron (220Rn) are radioactive isotopes of radon gas and are derived from the natural decay of uranium (238U) and thorium (232Th) respectively, present in the mineralogical composition of, particularly, igneous rocks. However, 222Rn present a half-life of 3.8 days while 220Rn has a shorter half-life of 55 seconds. High 222Rn activity surface measurements are considered to be associated to deep magmatic sources of gas, providing additional value on defining high porosity and permeable zones. On the contrary, due to its ephemeral half-life, high 220Rn activity is associated to shallow soil gas sources.

A detailed and regular surface geochemical survey was carried out in an area of 25 Km2 at the western side of La Palma island and southwards from the recent lava flow of Tajogaite Volcano. A total of 766 soil radon and thoron activities discrete measurements were performed (around 30 sample sites/Km2) using a SARAD radon monitor, model RTM-1688-2, connected to a stainless steel probe inserted at 40 cm depth. Data analysis and treatment showed an average 222Rn value of 1,056 Bq/m3, ranging from 0 to up to 27,000 Bq/m3, and an average 222Rn/220Rn ratio of 0.3, ranging from 0 to a maximum of 49. The spatial distribution maps has enabled to limit areas with higher values of these two variables,which might indicate zones of interest for further investigation. Higher soil 222Rn activity were concentrated along an specific segment of the coast line, which is coincident with the distribution of the well-known anomalous CO2 active diffuse degassing of volcanic origin in Puerto Naos and La Bombilla, which may have played an important role in controlling the migration and transport of these trace gases towards the surface. Radon and thoron gases activities measurements have revealed to be a worthwhile and non-invasive technique for surface exploration in highly environmental-threatened areas, like La Palma, helping to provide the definition of permeable areas and potential up-flow zones of potential geothermal system structures and permitting an efficient posterior subsurface exploration phase.

 

How to cite: Gironés, A., Valls, A., Thompson, M., Martín, A., Pérez, N. M., Melián, G. V., Padrón, E., Padilla, G. D., Hernández, P. A., Asensio-Ramos, M., and Rodríguez, F.: Geothermal prospecting by ground radon and radon/thoron ratio measurements at La Palma, Canary Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16021, https://doi.org/10.5194/egusphere-egu24-16021, 2024.

EGU24-16282 | Orals | ERE2.6 | Highlight

Lithium prospectivity and capacity assessment in the North German Basin 

Katharina Alms, Alicia Groeneweg, and Manfred Heinelt

Lithium production has increased tenfold over the past two decades and is expected to grow steadily over the next decade, driven by the rapid development of modern technologies such as mobile electronics, electric vehicles (EVs) and grid storage applications. The European Union including Germany, however, has no conventional lithium resources and is therefore geopolitically dependent on imports. As a result, unconventional resources such as lithium recovery from geothermal brines in the Upper Rhine Graben have been explored. Elevated lithium concentrations have also been reported in other regions including the North German Basin (NGB), but no resource estimates are available. Therefore, all available data for the NGB are summarized here in order to limit potential deposits. Their potential is then assessed using a probabilistic volume-based approach.

The highest concentrations are found in the Permian Rotliegend and the Zechstein Ca2 at the basin margin. Lithium concentrations can locally reach up to 600 mg/L in the Rotliegend and 300 mg/L in the Zechstein. Our resource estimates indicate that 0.08 to 5.76 Mt of lithium could be contained in the Rotliegend and an additional 0.06 to 3.06 Mt in the Zechstein. Elevated lithium concentrations have also been reported in the overlying Triassic Buntsandstein deposits that occur over much of the basin. Values of up to 200 mg/L lithium have been detected, which we estimate to be between 0.2 and 3.48 Mt of lithium.

On the one hand, our study shows that there are sufficient domestic lithium resources in geothermal waters. However, it is also clear that the most promising resources are associated with deep, low-permeability Permian deposits that inhibit conventional (non-engineered) hydrothermal geothermal energy production. It is therefore unclear whether geothermal energy production and lithium exploration can co-exist and further studies are needed to analyze the local, onsite potential. Our study provides the starting point for this analysis.

How to cite: Alms, K., Groeneweg, A., and Heinelt, M.: Lithium prospectivity and capacity assessment in the North German Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16282, https://doi.org/10.5194/egusphere-egu24-16282, 2024.

EGU24-16639 | Orals | ERE2.6

The chemical composition of the discharged fluid from IDDP-2, Reykjanes, Iceland 

Iwona Galeczka, Finnbogi Óskarsson, and Kiflom Gebrehiwot Mesfin

The IDDP-2 well at Reykjanes was drilled by Iceland Drilling Ltd. for HS Orka Ltd. in 2016 and 2017. The well was drilled as part of the Iceland Deep Drilling Project (IDDP), which aim has been to drill deep wells down to 4–5 km depth into geothermal systems in Iceland, involved casing and deepening the production well RN-15 from 2507 m to 4659 m.  Deepening of the well commenced on August 11th, 2016, and it was completed on January 25th, 2017. The most recent well test of RN-15/IDDP-2 was on 5th of May 2022. The well has a casing damage just below 2300 m depth, which hinders any logging below that depth. The main feed zones are probably at the depth of the casing damage (where the main feed zone of RN-15 was located) and at about 3400 m, but there may also be a minor feed zone near the bottom of the well. When the well is opened for discharge, fluid from these feed zones enters the wellbore, flows up the well and eventually reaches a boiling point. The fluid is then two-phase with a gradually increasing steam fraction up to the wellhead. The estimated enthalpy of the discharged fluid is from about 1107 kJ/kg to 1120 kJ/kg and the steam fraction is about 30%. The production from the well was 19.2 kg/s and 22.2 kg/s at wellhead pressure 13.5 bar-g and 7.8 bar-g, respectively. The estimated productivity index is 1.4 (kg/s)/bar, which indicates low-permeability feed zones.

The geothermometry of the collected fluid sample suggests a slightly higher reservoir temperature of 294°C compared to 290°C in 2016. Note that this difference is within analytical uncertainty for SiO2 analysis. The highest gas content measured during this study was 1.83 wt% and is higher than most of the RN wells. The deep fluid feeding the well is more diluted comparing to the fluid from RN-15 pre-2016. Most of the major non-volatiles are in a low range of the concentrations calculated for the Reykjanes reservoir. The RN-15/IDDP-2 aquifer is, however, enriched in volatiles such as CO2, H2S, N2, and H2 compared to their content during monitoring or RN-15 in 2004-2016. In general, the temperature and the composition suggest that fluid entering the well is not only sourced from 2300 m aquifer but also from deeper feed zones. 

The IDDP-2 was funded by HS Orka, LV, OR and OS, in Iceland, together with Equinor (former Statoil). The IDDP-2 also received funding from the EU H2020 (DEEPEGS grant no.690771) for all parts of the operation, and ICDP and US NSF (grant No.05076725) for spot coring and part of the related research

How to cite: Galeczka, I., Óskarsson, F., and Gebrehiwot Mesfin, K.: The chemical composition of the discharged fluid from IDDP-2, Reykjanes, Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16639, https://doi.org/10.5194/egusphere-egu24-16639, 2024.

EGU24-17038 | Posters on site | ERE2.6

Magnetotelluric and Gravity surveys of Pantelleria Island (Southern Italy) for geothermal exploration 

Maria Giulia Di Giuseppe, Stefano Carlino, Claudio De Paola, Giuseppe Ferrara, Giovanni Florio, Roberto Isaia, Fabio Pagliara, Tommaso Pivetta, Umberto Riccardi, Lorenzo Ricciardi, Monica Sposato, Antonio Troiano, and Luigi Zampa

Pantelleria island in Southern Italy represents an attractive target area for geothermal energy exploitation. The island is characterised by a high-temperature geothermal system (>150°C/km, as detected from deep borehole measurements), hot fluids, and CO2 diffuse degassing. Pantelleria has already been the subject of several studies to assess its geothermal potential. To further increase the knowledge about geometry and the physical properties of the main structures of the geothermal system, new magnetotelluric (MT) and gravity surveys have been carried out. The MT modelling relies on the inversion of data collected in 78 independent soundings covering the whole island. Through this survey, a 3D model of the electrical resistivity has been retrieved, highlighting the structures of Pantelleria down to a depth of 2.5 km b.g.l. A new gravity survey of about 120 stations allowed us to obtain new and more detailed Free Air and Bouguer gravity maps, with a spatial resolution of about 600 m. 

How to cite: Di Giuseppe, M. G., Carlino, S., De Paola, C., Ferrara, G., Florio, G., Isaia, R., Pagliara, F., Pivetta, T., Riccardi, U., Ricciardi, L., Sposato, M., Troiano, A., and Zampa, L.: Magnetotelluric and Gravity surveys of Pantelleria Island (Southern Italy) for geothermal exploration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17038, https://doi.org/10.5194/egusphere-egu24-17038, 2024.

EGU24-17431 | ECS | Orals | ERE2.6

Cold – water springs as integral part of geothermal systems: an example from Sri Lanka 

Dilshan Bandara, Jeroen Smit, Stefan Wohnlich, and Thomas Heinze

Hot water springs are typical surface manifestations of a geothermal system, especially in low enthalpy, amagmatic systems. In many of these systems, numerous cold-water springs are often associated with hot water springs. The smaller number of hot water springs and the wider spatial distribution between them make it difficult to perform a comprehensive study of such a geothermal system. In this case, associated cold water springs can be of particular help in understanding the hydrogeological setting of the geothermal system which is vital information for any future geothermal exploration programs.

There are 9 known hot springs in Sri Lanka, however they are spread over a larger area of the eastern lowlands of the country. On the other hand, there are over 225 known cold-water springs distributed among the hot water springs, making Sri Lanka a perfect location for a case study.

Most hot water springs are located at a great distance from their recharge zone (~ 50-100 km). With the exception of very few springs, cold water springs have short recharge to discharge distances (< 25 km). Geochemical and isotopic studies of the hot springs and the nearby cold springs show that both kinds are of the same origin and recharge at similar altitudes (> 600m). The electrical resistivity of cold-water springs is comparatively higher than that of rain and fresh surface water, but lower than that of hot water springs. This suggests that these cold spring waters also travel longer through the fault/fracture network through which hot spring waters circulate from recharge zones to discharge zones. These observations of cold-water springs show that they are also part of the geothermal system in Sri Lanka and reveal important information about the fluid flow paths of the geothermal system. The results and observations of the present study highlight the importance of cold-water springs in understanding the hydrogeological setting of a geothermal system. In addition, the new knowledge will be of significant benefit to future geothermal exploration programs, particularly in systems with a smaller number of hot water springs spread over a larger area.

How to cite: Bandara, D., Smit, J., Wohnlich, S., and Heinze, T.: Cold – water springs as integral part of geothermal systems: an example from Sri Lanka, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17431, https://doi.org/10.5194/egusphere-egu24-17431, 2024.

EGU24-17923 | ECS | Orals | ERE2.6

Soil CO2 emission and stable isotopes (δ13C, δ18O) of CO2 and calcites reveal the fluid origin and thermal energy in the supercritical geothermal system of Krafla, Iceland 

Giulio Bini, Giovanni Chiodini, Tullio Ricci, Alessandra Sciarra, Stefano Caliro, Anette K. Mortensen, Marco Martini, Andrew Mitchell, Alessandro Santi, and Antonio Costa

The Krafla geothermal system is located within a volcanic center that periodically erupts basaltic lavas, and has recently attracted an economic interest due to supercritical fluids forming near a shallow magma intrusion (~ 2 km depth). Here, we discuss new soil CO2 flux and stable isotope data of the CO2 efflux (δ13C) and hydrothermal calcites (δ13C, δ18O) of drill cuttings to estimate both the current magmatic outgassing from soils and the thermal flows in the geothermal system. Soil CO2 emission is controlled by tectonics, following the NNE-SSW fissure swarm direction and a WSW-ENE trend, and accounts for ~ 62.5 t d–1. While the δ18O of the H2O in equilibrium with deep calcites is predominantly meteoric, both the δ13C of the soil CO2 efflux and of the fluids from which calcite precipitated have a clear magmatic origin, overlapping the δ13C estimated for the Icelandic mantle (–2.5 ± 1.1 ). Estimates based on the soil CO2 emission from the southern part of the system show that these fluxes might be sustained by the ascent and depressurization of supercritical fluids with a thermal energy of ~800 MW. Such significant amount of energy might reach 1.5 GW if supercritical conditions extended below the whole investigated area. Finally, we report an increase in the soil CO2 emission of about 3 times with respect to 14 years ago, likely due to recent changes in the fluid extracted for power production or magmatic activity. Pairing the soil CO2 emission with stable isotopes of the efflux and calcite samples has important implications for both volcano monitoring and geothermal exploration, as it can help us to track magmatic fluid upflows and the associated thermal energy.

How to cite: Bini, G., Chiodini, G., Ricci, T., Sciarra, A., Caliro, S., Mortensen, A. K., Martini, M., Mitchell, A., Santi, A., and Costa, A.: Soil CO2 emission and stable isotopes (δ13C, δ18O) of CO2 and calcites reveal the fluid origin and thermal energy in the supercritical geothermal system of Krafla, Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17923, https://doi.org/10.5194/egusphere-egu24-17923, 2024.

EGU24-18004 | ECS | Orals | ERE2.6

Comparing the Performance of Single U-tube, Double U-tube and Coaxial Medium-to-Deep Borehole Heat Exchangers 

Christopher Brown, Isa Kolo, David Banks, and Gioia Falcone

The UK heating sector must be decarbonised to achieve net zero targets by 2050; and geothermal energy can help to provide low carbon heat. Closed-loop geothermal systems can provide low-risk solutions via the repurposing of ex-hydrocarbon and unused geothermal exploration wells. Closed-loop, medium-deep borehole heat exchangers (MDBHEs), at depths defined from 500-1000 m, could potentially use a variety of configurations, including single U-tube, double U-tube and coaxial. U-tube MDBHEs involve one or more pipes being inserted in the borehole with heat being transferred to a chilled circulating fluid within the U-tube(s) via conduction through any grout and the borehole wall. Coaxial MDBHEs consist of a concentric central pipe being inserted within an outer pipe (often, the borehole casing). Cool fluid is circulated down the annular space, gaining heat by conduction through the outer pipe wall, before being pumped to the surface through the central pipe. This study addresses the thermal and hydraulic performance of these different configurations under a range of geological and engineering conditions. Simulations were undertaken using OpenGeoSys software to evaluate optimal configurations by minimising hydraulic (and thus parasitic power) losses, while maximising the thermal output.
Under the base case scenario at 800 m, assuming water as the circulation fluid, it was observed at the end of the 25-year simulation, with a flow rate of 5 L/s and inlet temperature of 5 °C, that single U-tube, double U-tube and coaxial configurations provide specific heat extraction rates of 32.8, 36 and 39.1 W/m, respectively. These correspond to pressure losses of 1.46 MPa, 423 kPa and 85 kPa. From the analyses, it was observed that the coaxial configuration led to the lowest pressure losses and generally maximised the thermal output. The coaxial system was then applied to a case study for the Newcastle Science Central Deep Geothermal Borehole, where there are plans to repurpose the well to c.920 m in 2024 for geothermal testing. Results indicate that a thermal power of 50 kW could be attainable for a geothermal gradient of 33.4 °C/km, rock thermal conductivity of 2.5 W/(m.K) and flow rate of 5 L/s.

How to cite: Brown, C., Kolo, I., Banks, D., and Falcone, G.: Comparing the Performance of Single U-tube, Double U-tube and Coaxial Medium-to-Deep Borehole Heat Exchangers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18004, https://doi.org/10.5194/egusphere-egu24-18004, 2024.

Abstract :

Geothermal energy is becoming increasingly important in the transition to low-carbon and sustainable energy sources. The present article explores the Life Cycle Assessment (LCA) and the long-term sustainability of geothermal energy through the analysis of this sector’s impact from resource extraction to end-of-life in N-Hungary.

This study undertakes a thorough investigation with the goal of synthesizing current knowledge, identifying the geothermal system in the vicinity of Veresegyház, N-Hungary and offering a coherent understanding of geothermal energy as well as the environmental sustainability, since that this town is a notable example of a smart and conscious local community that recognized and harnessed its geothermal energy potential. Veresegyház started using geothermal energy in 1993, it has become one of the largest urban geothermal heating systems in Hungary, showcasing ongoing advancements in geothermal energy utilization. The total installed thermal capacity of the system is nearly 13 MW. The geothermal energy provides about 74 TJ annually, what leads to saving almost 2.2 million m3 natural gas per year. The geothermal system is used for heating and domestic hot water purposes; besides it has a total installed thermal capacity of nearly 13 MW and an extensive geothermal pipeline stretching 18 km making it one of Hungary's most comprehensive geothermal systems.

The aim in this article is to provide an insight into the geothermal technologies, exploring the appropriate methodology of life cycle assessment (LCA), and compare the results with previous studies.

Key Words:

Geothermal Energy, Renewable Energy, Life Cycle Assessment (LCA), Environmental Impact, Sustainability, Energy Transition, Case Studies, Policy, Carbon Footprint.

How to cite: Khedhri, R. and Hámor Vidó, M.: “Life Cycle Assessment of Geothermal Energy: preliminary overview of the Veresegyház geothermal system”, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18270, https://doi.org/10.5194/egusphere-egu24-18270, 2024.

EGU24-19205 | Posters on site | ERE2.6

Transversal structures in the Main Ethiopian Rift and implications for rifting, volcanism and geothermal systems 

Giacomo Corti, Marxo Benvenuti, Derek Keir, and Federico Sani

Although systems of extension-orthogonal normal faults are the typical expression of continental rifting, structures oblique or even sub-parallel to the plate motion vector may at places develop. These transversal structures, which may be related to reactivation of pre-existing structures, have been suggested to have a control on rift-related volcanism and caldera systems (for instance controlling their extension-parallel elongation) and on the circulation of fluids in geothermal fields associated to these volcanic features. Here we present data from the central sector of the Main Ethiopian Rift showing the existence of a major NW-SE trending system, which likely resulted from the linkage of major segments of the Main Ethiopian Rift exploiting pre-existing structures. This transversal structure, characterised by both a normal and right lateral slip component, influenced the morphology, hydrography, seismicity and volcanism in the area. Specifically, this NW-SE structure, and the interaction with the NE-SW faults delimiting the rift, controlled the location and alignment of silicic volcanism in the Bora-Bericha and Tulu Moye systems. Seismicity analysis indicates that this transverse structure is still active, reaching at least mid-crustal depths, and indicates that this structure is involved in the fluid circulation at upper crustal levels in the associated geothermal system. Therefore, transverse structures may have important influence on rift evolution and architecture and on the pathways of magma and on the flow pattern of crustal fluids, with important implications for geothermal activity related to continental rifting, as suggested for other important geothermal fields in the Main Ethiopian Rift.

How to cite: Corti, G., Benvenuti, M., Keir, D., and Sani, F.: Transversal structures in the Main Ethiopian Rift and implications for rifting, volcanism and geothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19205, https://doi.org/10.5194/egusphere-egu24-19205, 2024.

EGU24-19473 | ECS | Posters on site | ERE2.6

Integrated geothermal reservoir characterization in the North German Basin. 

Majdi Al-Howidy, Hartwig von Hartmann, Mehrdad Soleimani Monfared, and Inga Moeck

The North German basin characterizes challenges and unique opportunities of the geothermal reservoir because of the geological structure and geothermal potential. One of these challenges is the marine environments of Eocene deposits. This contains shallow marine environments where can changing sea levels lead to a variety of sediments from coastal sands to deep marine clays. Moreover, the uncertainty of reservoir features due to diagenetic processes over geological time can considerably change the original depositional characteristics of sediments. This study outlines a comprehensive investigation focused on classifying and analyzing shallow to medium-deep geothermal plays, mainly within the Brussels sand formation from the Tertiary sediments in the middle Eocene. We have selected this formation due to its appropriate thickness for geothermal reservoir studies and its lithological characteristics, previous studies have shown that the sediment sequence contains shale and sandy formation in Wilhelmshaven with a thickness of around 5 -130m. The approach that we are going to present in this study, leverages a combination of Geothermal, well, petrophysical well logs, and seismic data to build a rock model and perform a geothermal reservoir characterization in the area. A comprehensive investigation of the North German Basin's geothermal potential has been conducted, with a focus on the classification of play types. This classification is essential for understanding the range of geothermal systems present and their particular characteristics. The first stage contains the selection of areas with a geothermal potential based on the thickness of the formation, depth of the target formation, availability of 3D seismic data, the density of drilled wells, and the thermal gradient. Through a primary analysis and literature review, based on the aforementioned parameters, the sand bodies of the Brussels Formation were shown to be a suitable target for further exploration. Then it follows by a detailed analysis of underground temperatures of reservoirs in medium-deep depth. The dominant temperature of the geothermal reservoir in this depth and the selected target formation is expected to be classified as low, which can be suitable for heating purposes. These lower-temperature reservoirs are suited for district heating systems, especially when combined with heat pump technology. Heat pumps can raise the temperature of the geothermal heat to stages suitable for domestic and industrial heating. Then the integrated workflow of the temperature analysis and rock model investigation in this study can assist as a foundational framework for further detailed reservoir engineering studies and further economic assessment.

How to cite: Al-Howidy, M., von Hartmann, H., Soleimani Monfared, M., and Moeck, I.: Integrated geothermal reservoir characterization in the North German Basin., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19473, https://doi.org/10.5194/egusphere-egu24-19473, 2024.

EGU24-19542 | ECS | Orals | ERE2.6

Subsurface mass modelling at Theistareykir geothermal field, Iceland, using hybrid gravimetry. 

Beatrice Giuliante, Philippe Jousset, Charlotte Krawczyk, Jacques Hinderer, Umberto Riccardi, Nolwenn Portier, Florian Forster, and Anette K. Mortensen

Time lapse gravity measurements can give information on underground mass redistribution. Observations are especially valuable over the course of subsurface use, for instance during geothermal exploration of an area. To monitor the mass transfer of underground geothermal fluids associated with the harnessing of a hydrothermal system and to assess its long-term sustainability, we have performed long-term observations at Theistareykir (Icelandic North volcanic zone).

 

In this study, we model the mass and fluid displacement through the use of the hybrid gravimetry technique. Hybrid gravimetry is a method which consists of the combination of several complementary gravity observations. At Theistareykir, the following experiments are collecting data since 2017:

  • micro-gravity time lapse relative measurements are repeated yearly on a pre-designed network of points;
  • relative gravity measurements are recorded continuously at several multi-parameter stations deployed within and outside the geothermal area. Each station is equipped with a superconducting or a spring gravimeter as well as a GNSS receiver, a broadband seismometer and hydrological and weather sensors.
  • absolute gravity measurements are collected yearly, to constrain the instrumental drift of the relative gravimeters.

 

Here, we present the complete time series recorded by two superconducting gravity meters at Theistareykir since 2017. Gravity changes associated with potential vertical displacements of the continuous gravity meters are obtained from GNSS data, and removed from the raw data. Similar reductions are performed for other contributions from the meteorological data (pressure, snow height). The reduced time series have been used to obtain an accurate local Earth tide model. Such model is subtracted from the continuous gravity records in order to obtain the gravity residual, sensitive to the geothermal activities (injection, extraction).

From the analysis of the gravity time series we notice gravity decrease at the production site. This trend is also visible from the time lapse gravity changes maps, obtained by the integration of micro-gravity data with ground displacement data. Patterns from the spatial maps of gravity changes show gravity increase southwards of the injection area, suggesting drainage of the injected water along the Tjamaras fault. The modelling results are compared with mass changes estimated from the injection and production rates, provided by Landsvirkjun, the operating energy company, thereby constraining the interpretation.

 

Ongoing work encompasses forward modelling approaches to quantify mass transfers (extraction, injection, recharge, atmospheric losses) within the geothermal system.

How to cite: Giuliante, B., Jousset, P., Krawczyk, C., Hinderer, J., Riccardi, U., Portier, N., Forster, F., and Mortensen, A. K.: Subsurface mass modelling at Theistareykir geothermal field, Iceland, using hybrid gravimetry., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19542, https://doi.org/10.5194/egusphere-egu24-19542, 2024.

EGU24-19591 | ECS | Orals | ERE2.6

New insights on the meteoric recharge at the Le Biancane area (Larderello geothermal system) from fluid geochemistry 

Evelina Dallara, Matteo Lelli, Paolo Fulignati, and Anna Gioncada

Geothermal energy represents an important aspect of the ongoing green transition; therefore, geothermal reservoirs have to be properly investigated and studied in many and different aspects. In this frame, the Larderello geothermal field represents an important energy resource for the Tuscan region, and the first geothermal reservoir to be used for energy production. It is a vapor-dominated reservoir producing superheated steam and characterized by areas where the permeable formations of the shallower reservoir outcrops, with thermal manifestations at the surface, such as fumaroles and steaming-ground. In particular, the Le Biancane area, one of the main outcropping zones, represents a potential recharge point where meteoric water can infiltrate through the carbonate-anhydrite formations of the Tuscan Nappe.

Although the Larderello geothermal system has been studied since the beginning of the last century, a detailed and systematic investigation of the recharge in the infiltration potential areas is still missing. Indeed, only few chemical and isotopic data of meteoric waters and geothermal fluids in the Le Biancane area are available. These are not enough to give information on the main infiltration areas and origin of the geothermal fluids, considering also the re-injection of spent fluids that has been introduced since the ’70 in some of the wells. Therefore, with the aim to analyse in detail the recharge in the Le Biancane area, 11 fumaroles and 37 cold and thermal springs were sampled. In order to be able to well define the isotopic marker of this area, the investigated springs were selected on a wider area surrounding Le Biancane, on a regional scale. Two sampling campaigns have been carried out, one after the rainy season in May/June 2023 and one after the dry season in October 2023.

From isotopic analyses on fumarole condensates, differences in δD and δ18O were evident highlighting the possibility that these fluids undergo different processes before reaching the surface. Furthermore, fumaroles were analysed, among the many components, also for COS, which represents a new potential geo-indicator. On the other hand, regarding the water recharge investigation, in this work we will present the results of the isotopic hydrological approach on the spring samples.  

How to cite: Dallara, E., Lelli, M., Fulignati, P., and Gioncada, A.: New insights on the meteoric recharge at the Le Biancane area (Larderello geothermal system) from fluid geochemistry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19591, https://doi.org/10.5194/egusphere-egu24-19591, 2024.

EGU24-19773 | ECS | Posters on site | ERE2.6

EFECT: A tool for pore pressure projection and data management 

Malte Ziebarth, Michael Drews, Florian Duschl, Indira Shatyrbayeva, Oliver Heidbach, and Birgit Müller

Advance information about local pore pressure distribution is crucial for the drilling of deep geothermal wells. Incorrect adjustment of the drilling mud density leads to drastic differences between wellbore pressure and the ambient pore pressure. Large pressure differences may result in severe drilling problems such as kicks, wellbore instabilities and subsequent partial or full loss of the previous borehole progress. In particular for small geothermal ventures on a communal level, this loss may pose a significant financial risk.

We present current work on EFECT, a tool that helps to organize existing pore pressure measurement data and to generate geologically informed pore pressure estimates based on these existing data. EFECT integrates geographic information system (GIS) components that allow the user to explore pore pressure data sets and select offset wells for a planned well location. As a first step, the regional aggregate pore pressure model shows general features of the regional pore pressure with depth. The core feature of EFECT is the projection of the offset wells’ pore pressure to the target well based on matching stratigraphic units. Two projection algorithms are provided that assume either (1) overpressure or (2) vertical effective stress is constant between target and offset wells.

EFECT is part of a larger effort to develop a global pore pressure database with a standardized quality ranking. The data from this database, consisting of pore pressure measurements and indicators such as well tests, kicks and mud weight data, provide a standard that users may augment with their own data. This standard data set can be particularly useful for small geothermal ventures. We illustrate EFECT using data from a precursor of the global pore pressure database covering the SE German part of the North Alpine Foreland Basin (Bavarian Molasse Basin).

How to cite: Ziebarth, M., Drews, M., Duschl, F., Shatyrbayeva, I., Heidbach, O., and Müller, B.: EFECT: A tool for pore pressure projection and data management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19773, https://doi.org/10.5194/egusphere-egu24-19773, 2024.

EGU24-20195 | Orals | ERE2.6

Characteristics and mechanism analysis of geothermal resources innorthern Jianghan Basin 

Xiaofan Wan, Chuanbo Shen, and Xiang Ge

The geothermal energy in the northern Jianghan Basin is considered hydrothermal geothermal resources. Heat generation condition and thermal conduction mechanism are crucial factors affecting the migration of geothermal fluid. However, it is not clear about the controlling factors of geothermal distribution and formation modes in this region. To explore the spread, accumulation and preservation characteristics of geothermal resource in the northern Jianghan basin, the deep geological backgrounds and tectonic characteristics of the target area are analyzed. Also, the genetic model is conceived during the research to have a acquaintance with the process of geothermal energy evolution. Traditional methods, for example the inversion of gravity, magnetic, and electric, are applied to recognize the concealed rock. Besides, numerous data, including seismic, oil and gas wells, geothermal wells and hydrochemical composition, is used to analyze the characteristics of geothermal fields, properties of deep rock mass, structures of geothermal reservoirs and thermal conductivity of faults. The results show that the regional uplifts and depressions control the distribution of geothermal resources. In addition, what play a pivotal role in the connection between deep heat sources and upper prospecting reservoirs are boundary faults of the basin. What’s more, neotectonic activities of faults are beneficial channels for heat and water conduction. On the basis of above researches, the model of geothermal distribution related with fault systems is well established, confirming that geothermal resources are mostly distributed in conjunction zones of differed faults. The findings of this work provide scientific evidence for discovering other geothermal favorable areas in the Jianghan Basin.

How to cite: Wan, X., Shen, C., and Ge, X.: Characteristics and mechanism analysis of geothermal resources innorthern Jianghan Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20195, https://doi.org/10.5194/egusphere-egu24-20195, 2024.

EGU24-21159 | ECS | Orals | ERE2.6

Formation mechanism of high-temperature geothermal resources in the Songliao Basin 

Boning Tang, Nansheng Qiu, and Chuanqing Zhu

The Songliao Basin, situated in Northeast China, boasts a significant geothermal background evident in numerous boreholes, indicating a rich geothermal resource potential with temperatures exceeding 150℃ at depths of 5km. This study aims to elucidate the formation mechanism of high-temperature geothermal resources in the Songliao Basin, analyzing various aspects such as the thermal properties of rocks, temperature fields, terrestrial heat flow, heat source contributions, Meso-Cenozoic thermal history, deep thermal structures, and factors influencing geothermal resource formation. The research offers valuable theoretical support for the exploration and evaluation of high-temperature geothermal resources in the Songliao Basin. The research involves testing the rock thermal conductivity of 263 core samples and 99 outcrop samples, as well as the rock heat generation rate of 80 core samples and 56 outcrop samples from the Songliao Basin and its periphery. The measured thermal conductivity ranges from 0.58 to 3.94W/(m·K), with an average value of 1.96 W/(m·K). Heat generation rates vary between 0.31 and 4.98μW/m³, averaging 1.72μW/m³. A comprehensive thermal conductivity and heat generation column for the Songliao Basin was established by integrating current testing data with previous records. Based on data from over 3000 oil test temperatures collected in this study and previous temperature data compilations, the temperature distribution characteristics of the Songliao Basin were clarified. The overall geothermal gradient averages 40-50℃/km, with terrestrial heat flow ranging between 50-100 mW/m² and exceeding 80 mW/m² in most areas. The heat generation contribution from different lithologies in each stratum was calculated based on the heat generation rate. The sedimentary layer's heat generation contribution is primarily between 5-10 mW/m². The mantle heat flow surpasses crustal heat flow, constituting approximately 60% of the total heat flow. A partial melt in the crust of the Songliao Basin contributes about 10% to heat generation contribution, with a notable impact on mantle heat flow. The Songliao Basin underwent testing for apatite fission track and (U-Th)/He age, coupled with a Meso-Cenozoic thermal history simulation. The outcomes reveal a substantial cooling trend in the basin starting at the end of the Cretaceous period, persisting to the present day. This analysis contributes to a more comprehensive understanding of the formation history of the current geotemperature field within the study area. The study analyzes the influence of the deep thermal background on high-temperature geothermal accumulation by scrutinizing the distribution characteristics of thermal lithospheric thickness, the Moho surface, and the Curie isotherm, along with exploring the correlations among these factors. A comprehensive analysis, considering reservoirs, channels, caps, and fluid origin, establishes the formation conditions of high-temperature geothermal resources. Factors controlling and high-temperature geothermal accumulation are clearly defined, culminating in the establishment of a high-temperature geothermal accumulation model for the Songliao Basin.

How to cite: Tang, B., Qiu, N., and Zhu, C.: Formation mechanism of high-temperature geothermal resources in the Songliao Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21159, https://doi.org/10.5194/egusphere-egu24-21159, 2024.

Xiongan New Area is located in the middle of North China Plain, with high background heat flow values and abundant geothermal resources. However, the degree of development of geothermal resources in Xiongan New Area is different, and the understanding of the hydrochemical formation and evolution is not comprehensive. Geothermal water and cold groundwater in Rongcheng uplift, Niutuozhen uplift, Baxian depression, Baoding depression and Gaoyang low uplift were sampled for hydrochemical analyses. There are two types of thermal reservoir in the study area: sandstone and karst thermal reservoir. Minghuazhen formation and Guantao formation had relatively shallow buried depth, and the hydrochemical types were mainly Cl·HCO3-Na and Cl-Na type. The main hydrochemical type of Wumishan formation was Cl·HCO3-Na. Due to the high degree of homogenization of karst reservoir, the spatial difference of hydrochemical characteristics was relatively small. From shallow to deep, the TDS value of geothermal water increased. Due to the influence of the water conduction in the fault zone, the mixing phenomenon of geothermal water in some deep Wumishan and Guantao formation occurred. The metamorphic coefficient and desulfurization coefficient of geothermal water in Wumishan formation were lower than that of Guantao formation, and the thermal storage was relatively closed and in relatively reduced state, while the sealing of geothermal water in Guantao formation and Minghuazhen formation was relatively poor. Our result is of great significance to understand the geothermal resources in Xiongan New Area and to promote the clean heating in winter in northern China.

How to cite: Xing, Y.: Analysis on the Chemical Field Characteristics and Influencing Factors of Geothermal Water in Typical Area of North China Plain , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21715, https://doi.org/10.5194/egusphere-egu24-21715, 2024.

EGU24-22111 | ECS | Posters on site | ERE2.6

Passive seismic exploration with a dense network of 700 sensors in the Canton of Jura, Switzerland 

Genevieve Savard, Iván Cabrera-Pérez, Julien Sfalcin, and Matteo Lupi

As part of the Net Zero climate strategies of the European Union and Switzerland, deep geothermal power production is given an important role to play as a baseload energy resource. In Switzerland, the Haute Sorne project of Geo-Energie Suisse is the first EGS geothermal project to take place since the unsuccessful project of Basel terminated in 2010. The Canton of Jura, where Haute Sorne is located, gave the green light to Geo-Energie Suisse in January 2022. To minimize the risk of damaging induced seismicity as in 2017 during the Pohang EGS project, innovative state-of-the-art exploration and monitoring methods at Haute Sorne are being implemented to reduce subsurface uncertainty and de-risk the project as much as possible.

In this context, the University of Geneva is deploying a seismic network of 700 nodal sensors in February 2024 in a radius of 12 km around the planned Haute Sorne EGS site. The sensors will record continuous 3-component seismic velocity data passively over 30 days. Using ambient noise tomography techniques, this study aims to image at up to 5 kilometres depth regional-scale structures relevant to seismic hazard assessment and to understand the local seismo-tectonic context. Particular interest is given to basement-related structures including a nearby presumed Permo-Carboniferous trough. By examining anomalies in shear-wave velocity, radial anisotropy and/or attenuation, we aim to elucidate the presence of deep faults and/or deep fluid reservoirs. In this presentation, we will report the outcomes of the nodal deployment campaign, the quality of the data collected, preliminary ambient noise observations and the methods to be applied. Passive seismic campaigns with temporary nodal networks have great potential for geothermal exploration due to their low cost, easier permitting process, and ability to image basement-related structures with appropriately designed networks.

How to cite: Savard, G., Cabrera-Pérez, I., Sfalcin, J., and Lupi, M.: Passive seismic exploration with a dense network of 700 sensors in the Canton of Jura, Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22111, https://doi.org/10.5194/egusphere-egu24-22111, 2024.

Ground-coupled heat pump systems exchange heat between a building and the surrounding ground. To simulate a ground heat exchanger (GHE), a transfer function is commonly used. This function represents the ground's capacity to exchange energy. Its use allows for the simulation of the ground's response to different heat load patterns. The heat transfer process is affected by key factors such as the ground's thermal properties and the groundwater flow. Accurate evaluation is critical for designing the GHE field to meet the thermal needs of a building for heating and cooling.

The transfer function of the GHE represents its heat transfer over a time range from seconds to years of operation. The long-term component is usually defined by an analytical model, while the short-term component requires a more complex model to be evaluated. Indeed, analytical models do not accurately represent the transient heat transfer effects that occur in the borehole materials and heat transfer fluid. To avoid using thermal transfer models, the data from a thermal response test (TRT) can be used to retrieve an experimental transfer function. This study aims to outline the different applications of a deconvolution algorithm to retrieve a short-term transfer function from experimental TRT data.

Applying a deconvolution algorithm to the outlet temperature signal of a TRT allows for estimation of the short-term response of the GHE without the need for a defined thermal model. The algorithm can iterate on the transfer function form, enabling accurate reconstruction of experimental temperature. One advantage of this method is that it only requires experimental data from a TRT to construct the transfer function.

The methodology is applied to tests with constant and varying operating conditions, allowing to obtain one or more transfer functions depending on the number of operating conditions. Additionally, a deconvolution algorithm can be utilized to interpret distributed thermal response tests, helping in the identification of geological layers with the best thermal properties. This can assist system designers to reduce drilling costs for systems with multiple boreholes. Results present transfer functions that are smooth and close to ones obtained from a more advanced numerical model. Additionally, they can reconstruct experimental temperature precisely. It is worth noting that the transfer function curve is affected by groundwater flow, with larger flows resulting in a decrease in the curve for similar operating conditions.

In conclusion, this research demonstrates the diverse applications of a deconvolution algorithm in interpreting a thermal response test across various geological settings, groundwater flow rates, operating conditions, and types of GHE. This leads to the estimation of a short-term transfer function, which can be used either to compute thermal parameters or validate various heating loads on the GHE through implementation in a simulation algorithm.

How to cite: Dion, G. and Pasquier, P.: Experimental transfer function of ground heat exchanger from thermal response tests using a deconvolution approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2003, https://doi.org/10.5194/egusphere-egu24-2003, 2024.

EGU24-3764 | ECS | Posters on site | ERE2.7

Experimental Investigation of Thermal Dispersion Within Porous Media Under Natural Groundwater Flow Conditions 

Byeong-Hak Park, Ji-Young Baek, Gabriel C. Rau, and Kang-Kun Lee

Recent studies in the field of shallow geothermal applications emphasize the crucial role played by mechanical thermal dispersion as a fundamental heat transport mechanism within saturated porous media. However, Previous studies have overlooked or underestimated mechanical thermal dispersion, leading to a scarcity of information on thermal dispersivity in the literature. This study experimentally and numerically investigates the validity of general assumptions concerning mechanical thermal dispersion within a porous medium. For this purpose, comprehensive laboratory experiments were conducted using heat and solute tracers across various porous materials at different background flow velocities (Re < 0.52). The analysis results suggest that water injection induces substantial mechanical dispersion, even at low flow velocities. Additionally, the thermal dispersivity ratio may deviate from the assumed value, underscoring its importance in the environmental impact assessment of the thermal use of shallow aquifers. Our experimental findings also suggest that thermal dispersion is affected by both local thermal non-equilibrium and small-scale heterogeneity.

Keywords: Thermal dispersion; Water injection; Thermal dispersivity ratio; Local thermal non-equilibrium; Small-scale heterogeneity

 

Acknowledgements

This work was supported by the Nuclear Research  and  Development  Program  of  the  National  Research  Foundation  of  Korea  (NRF-2021M2E1A1085200). This work was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2022R1A2C1006696).

How to cite: Park, B.-H., Baek, J.-Y., Rau, G. C., and Lee, K.-K.: Experimental Investigation of Thermal Dispersion Within Porous Media Under Natural Groundwater Flow Conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3764, https://doi.org/10.5194/egusphere-egu24-3764, 2024.

EGU24-3869 | ECS | Posters on site | ERE2.7

Global sensitivity analysis of model parameters, heat transport processes and design parameters in ATES Systems  

Luka Tas, Thomas Hermans, Martin Bloemendal, and Niels Hartog

Shallow geothermal energy has not only great potential to mitigate CO2 emissions associated with the heating and cooling of buildings but also offers wide applicability. Thick productive aquifer layers have been targeted first, as these are the most promising areas for aquifer thermal energy storage (ATES). Nevertheless, there is an increasing trend to target more complex aquifers such as low-transmissivity and alluvial aquifers or fractured rock formations. However, the uncertainty and thus the risk of failure in these contexts is significantly higher and it is therefore often not sufficient to rely on experience when designing the ATES system. In this context, a distance-based global sensitivity analysis was carried out for ATES. The analysis focused on one promising thick productive aquifer, used as a reference, as well as two more complex settings involving a low transmissivity and a shallow alluvial aquifer. Through this method, multiple random model realizations are generated by sampling each parameter from a predetermined range of uncertainty. A distance measure between the different model realizations can then be used to determine the relative importance of the uncertain parameters. Not only hydrogeological parameters but also operational and design parameters and boundary conditions were considered uncertain. The parameter distributions were also further analyzed to make a connection with the ATES efficiency. Finally, specific attention was paid to exploring the thermal energy exchange between the soil and the aquifer and its significance for ATES efficiency in shallow aquifers. The results of this study give insight into how the sensitive parameters change when the setting becomes more complex and if it is required to include heat transfer processes that are commonly ignored in traditional settings. This nuanced understanding contributes to the optimization of ATES systems, offering practical guidance for enhanced efficiency of feasibility studies, especially in challenging environments.

How to cite: Tas, L., Hermans, T., Bloemendal, M., and Hartog, N.: Global sensitivity analysis of model parameters, heat transport processes and design parameters in ATES Systems , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3869, https://doi.org/10.5194/egusphere-egu24-3869, 2024.

EGU24-3990 | ECS | Posters on site | ERE2.7

The potential of subsurface heat recycling in Dresden 

Verena Dohmwirth, Susanne Benz, and Matthias Mauder

In times of climate change heat increasingly accumulates in urban areas. Thus, the temperature in city centers is often several degrees higher than in the surrounding areas. This urban heat island effect (UHI) can negatively affect people and the environment. Heat islands in the subsurface (SubSUHI) due to high heat input from cities into the soil and groundwater can also be measured. This accumulated heat input could be harnessed by geothermal heat pumps contributing to the solution of two major challenges of our time: firstly, the reduction of CO2 emissions through the decarbonization of the heating market and secondly, the cooling of the soil and groundwater to pre-industrial temperature levels and thus a possible climate protection measure.

This work attempts to investigate the heat island effect in the subsurface of the urban area of Dresden, Germany. For this purpose, various temperature measurements, such as groundwater and air temperature, are combined with geodata on land use and development. The theoretical geothermal potential for suitable areas in Dresden is calculated as well as the sustainable geothermal potential, taking into account the heat flux directed upwards as well as downwards. Several, mostly anthropogenic, heat fluxes from urban structures into the groundwater are investigated, such as heat fluxes due to buildings, tunnels, or district heating. These potentials are placed in the context of the heating requirements of the city of Dresden and thereby descripe the extent to which the installation of geothermal systems can contribute to the climate neutrality of the local heating market. In a second scenario, the heat fluxes for the year 2100 are calculated using the CMIP6 scenarios SSP245 and the SSP585 to show how climate change could potentially improve the efficiency of geothermal systems. By using Google Earth Engine as a platform, we ensure that our analysis is easily scalable and can later be applied to any city within Germany.

How to cite: Dohmwirth, V., Benz, S., and Mauder, M.: The potential of subsurface heat recycling in Dresden, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3990, https://doi.org/10.5194/egusphere-egu24-3990, 2024.

EGU24-5378 | ECS | Orals | ERE2.7

Tuning the performance of a borehole heat exchanger array in response to transient hydrogeological conditions 

Hesam Soltan Mohammadi, Lisa Maria Ringel, Christoph Bott, and Peter Bayer

Most shallow geothermal systems harness renewable energy from the ground by circulating a heat-carrier fluid through borehole heat exchangers (BHEs). While these systems have emerged as promising contributors to the ongoing energy transition, open questions regarding their durability and performance in practical applications remain. Critical factors are the uncertainty in the long-term heating/cooling demand as well as the uncertainty in the evolution of the ground thermal conditions. To enhance the environmental and economic appeal of such systems that should be operated for decades, optimal control procedures that adjust the heat extraction during the course of operation have been proposed. In this study, we introduce an improved sequential simulation-optimization procedure to tune the efficiency of BHEs exposed to transient groundwater flow conditions. The variability of groundwater flow not only perturbs subsurface heat transfer but also impairs the predictability through standard BHE modeling tools. For example, the well-established moving finite line source (MFLS) formulation offers no capabilities to represent transient trends in advective heat transport associated with groundwater flow. We restructure the MFLS by a time-varying groundwater flow term that ensures compliance with thermal equilibrium assumptions. This modified variant is validated with a numerical model and then interfaced with a linear programming algorithm to optimize the operation of the BHE array. To examine the efficacy of the proposed procedure, a synthetic field containing ten BHEs operating in the heating mode is implemented. Three distinct groundwater fluctuation scenarios, with monthly resolutions over a ten-year operational lifespan, are considered. The groundwater flow dynamic exhibits variations in an increasing, decreasing, and periodic manner. As the objective, local cooling is to be minimized. This is achieved by determining the monthly optimal load pattern for individual BHEs. The proposed methodology employs a cost function to minimize the maximum temperature change over two distinct temporal terms. The first term considers the entire operational lifetime, while the second term focuses on a forthcoming 12-month horizon.
The proposed methodology does not only achieve optimal BHE operation, but it also facilitates calibrating unknown or transient model parameters. This is demonstrated for the groundwater flow velocity that is estimated by solving a nonlinear least-squares problem using the trust-region-reflective algorithm. The benefit of sequential learning is compared with results obtained by optimization without any model calibration. This calibration-optimization routine, informed by transient temperature changes in the simulated ground, outperforms sequential optimization that relies on non-tunable model parameters.

How to cite: Soltan Mohammadi, H., Ringel, L. M., Bott, C., and Bayer, P.: Tuning the performance of a borehole heat exchanger array in response to transient hydrogeological conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5378, https://doi.org/10.5194/egusphere-egu24-5378, 2024.

EGU24-6026 | ECS | Orals | ERE2.7

Local thermal non-equilibrium (LTNE) effects revealed through porous media heat transport experiment 

Haegyeong Lee, Manuel Gossler, Kai Zosseder, Philipp Blum, Peter Bayer, and Gabriel Rau

Precise prediction of heat transport in porous media holds crucial significance in Earth Sciences for diverse applications, ranging from the design of geothermal systems to utilizing heat as a tracer in aquifers. Traditionally, the description of heat transport has been simplified by assuming local thermal equilibrium (LTE), where the temperature within the fluid and solid phases in the representative elementary volume is presumed to reach an instant equilibrium. In reality, assuming two distinct phases coupled by heat transfer across their surface area describes the complete physics and is referred to as the local thermal non-equilibrium (LTNE) model. While earlier research delved into the theoretical aspects of LTNE effects, a notable gap exists due to the absence of experimental data to elucidate the heat transport mechanism in porous aquifers containing natural grains. To address this gap and investigate LTNE on a granular scale, we conducted systematic flow-through experiments employing porous media containing glass spheres with distinct grain sizes of 5, 10, 15, 20, 25 and 30 mm. Each sphere contained a small temperature sensor for the solid temperature, accompanied by sensors in the adjacent pore space to measure the fluid temperature. Our findings revealed that the temperature difference between two phases grows with increasing grain size and flow velocity ranging from 9 to 61 m d-1, thereby highlighting qualitative LTNE effects in relation to grain size and flow velocity. To further enhance our understanding, we used a numerical model to investigate the heat transfer coefficient, fitting the LTNE model to the experimental data. These simulation results indicated evidence of non-uniform flow which we included into our model to estimate its effects on heat transport. This comprehensive approach contributes valuable insights into the intricate interplay of LTNE effects, grain sizes, and flow velocity, advancing our understanding of heat transport in natural porous media.

How to cite: Lee, H., Gossler, M., Zosseder, K., Blum, P., Bayer, P., and Rau, G.: Local thermal non-equilibrium (LTNE) effects revealed through porous media heat transport experiment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6026, https://doi.org/10.5194/egusphere-egu24-6026, 2024.

Aquifer Thermal Energy Storage (ATES) can store and supply a high capacity of seasonal heating and cooling. Well-balanced and well-designed ATES systems provide a very efficient energy storage, up to around 70-90% and thereby play an important role in providing a sustainable, and low-carbon solution for heating and cooling. Factors affecting the efficiency and capacity of ATES deployments are mainly subsurface properties and related design decisions. We set up a framework to test the impact of a wide range subsurface and design parameters to deduce their impact on ATES system performance. Aquifer thickness, lateral permeability and permeability anisotropy are considered as main aquifer properties, and cool-warm well lateral spacing and vertical offsetting of cool and warm plumes as main design decisions. The thickness of the injection and production interval can be dictated by aquifer permeability variations and/or be chosen by varying screen length.  

The parameters listed above are combined into dimensionless numbers, such as effective aspect ratio of the system and effective lateral spacing of wells to summarize and group different aquifers and possible ATES deployment designs. For a wide range of effective aspect ratios and effective well spacing ATES system behaviour is predicted by flow simulation and key performance indicators computed, including thermal efficiency, CO2 savings, cool/warm plume sizes and stored energy density. The first two indicate the potential expected capacity of ATES systems. The latter provide recommendations for best use of land area, especially if multiple ATES systems are planned in areas with high concentration of cooling and heating demand. Given heating and cooling demand, specific aquifer conditions and land area available for use, the predicted behaviour metrics will help design optimal ATES deployments and show the potential for energy savings across multiple different settings.

Results indicate that ATES’ bidirectional subsurface thermal storage nearly always produces more energy than unidirectional open-loop systems, even when thermal recovery is low. Only when cold and warm plumes are placed side-by-side, closer than half thermal radius apart, negative thermal efficiency occurs, and more energy is put in the system than extracted. However, placing cold and warm plumes at very small spacing is still efficient, when plumes are also offset vertically, and similar thermal behaviour as large lateral well spacing is achieved.

How to cite: Jacquemyn, C. and Jackson, M. D.: Impact of aquifer properties, well spacing and vertical offsetting of warm and cool plumes on ATES systems., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6390, https://doi.org/10.5194/egusphere-egu24-6390, 2024.

EGU24-6479 | Posters on site | ERE2.7

The "XEGCat project" - The subsurface monitoring network for shallow geothermal research in urban areas of Catalonia 

Ignasi Herms, Georgina Arnó, Víctor Camps, Montse Colomer, Sandra Armengol, Norbert Caldera, Ernest Orriols, Toni Marcè, Àlex Elvira, Jose Antonio Jara, Lucia Struth, Jordi Garcia-Céspedes, and Guillem Piris

The "XEGCat project" is a project funded by the ICGC Contract Program initiated in 2019. The objective is the implementation of instrumented boreholes designed to collect relevant scientific data on the thermal behavior of the subsoil. This data can be utilized for assessment, modeling, and the creation of maps depicting the shallow geothermal resources (SGR) on the urban scale. It also aids in the simulation and design of specific projects involving GSHP. Additionally, the project will allow long-term research on the progress of the subsurface urban heat island effect. The potential for deploying sustainable SGR schemes in the subsoil depends on the geological and hydrogeological characteristics of the subsoil, as well as the distribution of temperature at depth. Therefore, understanding these variables is crucial for assessing their potential use. The networks consist of instrumented boreholes equipped with sensors of various characteristics to measure and automatically record the subsoil temperature at different depths, and the position of the piezometric level in the existing subsoil and aquifers. The acquisition systems are equipped with dataloggers, and SIM cards powered by a 30 W photovoltaic panel. This setup enables automatic transmission of data to the ICGC server or storage on site, to be periodically collected in the field. The data is uploaded and organized by the NetMon© spatial database management system. Through a web service, the data can be consulted, analyzed, and downloaded using the ICGC viewer - Geoindex XEGCat. The data is also utilized by ICGC to develop new 3D subsoil models. By the end of 2023, up to two networks have been deployed: one in the city of Girona (NE, Catalonia) and another in the city of Tarragona (SE, Catalonia). A third specific local network has been deployed in the Aran Valley in the town of Vielha (Catalan Pyrenees). Over the next two years, there are plans to deploy a new urban network in the city of Lleida (W, Catalonia).

How to cite: Herms, I., Arnó, G., Camps, V., Colomer, M., Armengol, S., Caldera, N., Orriols, E., Marcè, T., Elvira, À., Jara, J. A., Struth, L., Garcia-Céspedes, J., and Piris, G.: The "XEGCat project" - The subsurface monitoring network for shallow geothermal research in urban areas of Catalonia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6479, https://doi.org/10.5194/egusphere-egu24-6479, 2024.

EGU24-7836 | ECS | Posters on site | ERE2.7

Fossil to renewable – how to speed up the installation of borehole heat exchangers? 

Kosztadin Gergő Glavanov, Ábel Markó, Pásztor Domokos, and Judit Mádl-Szőnyi

Geothermal heat pumps coupled with borehole heat exchangers are appropriate tools to extract renewable and climate- friendly energy from the shallow subsurface. To properly construct these systems, knowing the initial temperature conditions is essential. However, drilling activity modifies the temperature field in the underground around the borehole as well as in the pipe placed into the borehole. During the installation it has to wait for a constant temperature in the pipe after the probe is placed, before measuring the final temperature. According to the rule of thumb, this period is usually one week. The objective of this study is to determine whether this time is really necessary or if a shorter period would be also enough for reaching the undisturbed temperature. The measurements took place in the 11. district of Budapest, Hungary. The analysed borehole was drilled with rotary method deepened into the Budai Marl Formation with a depth of 70 metres. We executed four measurements on the first day, two on the next day, and one after that for four days. The most significant differences can be noticed between the first day measurements. After the third day, the received curves fit better, but they only approached each other from the fourth day with only 0.1-0.2°C difference. It can be concluded that a stable temperature profile required 72 hours of resting for this specific case which is shorter than the supposed one week. With this knowledge, assuming similar behaviour in other cases, installation period of borehole heat exchangers can be significantly shortened. Next step of this research is investigating other geological and seasonal conditions to reveal potential deviations from the current results.

The study was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21- 2022-00014 project.

How to cite: Glavanov, K. G., Markó, Á., Domokos, P., and Mádl-Szőnyi, J.: Fossil to renewable – how to speed up the installation of borehole heat exchangers?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7836, https://doi.org/10.5194/egusphere-egu24-7836, 2024.

EGU24-7965 | ECS | Orals | ERE2.7

Thermo-mechanical response of a cast in situ displacement energy pile 

Mouadh Rafai, Diana salciarini, and Philip J Vardon2

Displacement cast in situ Fundex (DCSF) energy piles are a new type of energy pile with the advantages of convenient construction, simple manufacturing, low vibration, and low noise and cost. This work focuses on the response of a stand-alone DCSF energy pile under different mechanical loads simultaneously with the operation of a ground source heat pump through a series of full-scale field tests. After applying an axial load on the pile head (60% of the bearing capacity), the pile was subjected to ten thermal cycles. The effects of mechanical load and the impact of temperature on the mechanical capacity of the DCSF energy pile were investigated. 

The results indicate that the cyclic thermal loadings induce a progressive increase in the compressive stress of piles. Furthermore, a residual compressive stress was observed and attributed to the drag-down effects of the surrounding soil.

During cooling phase, the tensile stress induced by thermal load decreased drastically due to the shrinkage of the near soils, leading to an insignificant effect on the energy pile during cooling. The maximum thermo-mechanical axial compressive stress in the foundations was approximately 1.55 MPa, well within structural limits and not expected to affect the building.

Progressive pile head displacement was observed indicating that thermal creep can affect pile head displacement at higher working loads.

How to cite: Rafai, M., salciarini, D., and Vardon2, P. J.: Thermo-mechanical response of a cast in situ displacement energy pile, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7965, https://doi.org/10.5194/egusphere-egu24-7965, 2024.

EGU24-8009 | Posters on site | ERE2.7

Comparative Environmental Impact of Ground Source Heat Pumps and Air Source Heat Pumps for Dwellings with high and low insulation profiles 

Lazaros Aresti, Christos Makarounas, and Paul Christodoulides

Following the European Union (EU) targets towards the “Fit for 55”, the heat pump (HP) sales have seen an increase. The recent increasing demand in the utilization of HP towards space heating and cooling, underscores the pivotal role of Shallow Geothermal Energy (SGE) systems and the Ground Source Heat Pumps (GSHPs). Although GSHPs exhibit higher performance compared to Air Source Heat Pumps (ASHPs), the high initial cost and the consequent long payback period has been a preventive factor for the GSHP systems. The GSHP systems however also benefit for additional CO2 reduction. The evolving efficiency of ASHP systems in recent studies challenge the perceived advantages associated with GSHPs, particularly in light of the continual refinement of ASHP systems.

This research embarks upon a comprehensive analysis to compare the environmental impacts, in terms of CO2 emissions, between ASHP and GSHP systems using different case studies. High insulation profile case studies were considered, following the nearly Zero Energy Buildings (nZEB) technical characteristics, as well as retrofitting at older dwellings with a low insulation profile. The current study engages a Life Cycle Analysis (LCA) with the OpenLCA software in conjunction with the Ecoinvent database, and the employment of the ReCipe impact method, both from a midpoint and an endpoint perspective. The findings derived from this investigation demonstrates a favorable performance of the GSHP systems where there is an increasing demanding in heating such as in the retrofitting cases. This research highlights the important environmental implications of employing the GSHPs over the use of ASHPs.

How to cite: Aresti, L., Makarounas, C., and Christodoulides, P.: Comparative Environmental Impact of Ground Source Heat Pumps and Air Source Heat Pumps for Dwellings with high and low insulation profiles, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8009, https://doi.org/10.5194/egusphere-egu24-8009, 2024.

EGU24-9213 | ECS | Posters on site | ERE2.7

Temperature impact of open-loop systems on groundwater in an urban area: A case study of Murska Sobota, NE Slovenia 

Simona Adrinek, Mitja Janža, and Mihael Brenčič

To achieve sustainable and efficient use of shallow geothermal resources, it is important to understand the heat transfer in the subsurface of the planned geothermal system. In the City Municipality of Murska Sobota, NE Slovenia, the use of geothermal open-loop systems has increased in recent years. Their high spatial density raises the question of potential mutual interference between the systems. By compiling geological, hydrogeological, and thermal data, obtained from the monitoring network, fieldwork, and knowledge of regional hydrogeological conditions, we have developed a transient groundwater flow and heat transfer model to evaluate the impact of the open-loop systems on the subsurface and surrounding systems. Time series data cover time span ranging from December 2019 to the end of December 2021. The sensitivity analysis showed the highest composite sensitivity values for hydraulic conductivity, porosity and dispersivity parameters, which were further calibrated with FePEST to minimize the error between groundwater level and temperature. The results of the groundwater flow model correspond well with the measured average groundwater levels. On the other hand, the thermal model shows higher deviations from the measured data, especially in the summer months when the simulated groundwater temperatures do not exceed 14.3 °C, while the measured temperatures reached even 15.4 °C. These deviations could be related to the effects of local thermal sources on the surface (e.g., sewage pipes, plumbing, buildings with more than one basement and roads), which were not considered in our model. The transient simulation showed that the thermal state in the observed area is restored over the summer, when the systems are not in operation. Also, the systems do not have significant mutual interference that would affect their efficiency. However, as interest in installing new systems in the area increases, simulations of the thermal plumes of new geothermal systems are needed to ensure sustainable and efficient use of shallow geothermal energy in the future.

How to cite: Adrinek, S., Janža, M., and Brenčič, M.: Temperature impact of open-loop systems on groundwater in an urban area: A case study of Murska Sobota, NE Slovenia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9213, https://doi.org/10.5194/egusphere-egu24-9213, 2024.

EGU24-9305 | Posters on site | ERE2.7

Thermal and thermohaline variable-density flow and salt transport in a 2D flow tank: Experiments, visualization and modelling 

Thomas Graf, Alexander Basten, Olaf A. Cirpka, Insa Neuweiler, Mohammad A. Rahmann, and Frank Spitzenberg

We carried out laboratory experiments of free thermal and thermohaline convection in homogeneous isotropic media using a laboratory-scale two-dimensional tank filled with glass beads representing a porous medium. Glass beads of different diameter were used in different experiments to achieve different permeabilities of the porous medium. Density and viscosity of the fluid were changed by initially introducing a salt (NaCl) solution, and by applying a heating device placed inside the tank. Fluid temperature inside the tank was measured over time on multiple thermocouples placed inside the tank on the inner glass walls. The fluid was dyed with two color tracers in order to visualize the emerging free convective flow pattern. The convective flow pattern was captured using a digital camera for the tracer distribution, and an IR camera for the temperature distribution. In subsequent numerical simulations, the experiments were successfully simulated numerically including density/viscosity variations and heat loss of the tank to the laboratory air across the back and front glass panes. Flow and transport parameters were calibrated using the results of the experiments with constant salinity. The set of calibrated parameter values was applied to successfully validate a thermohaline experiment with no need for further calibration. The processes of salt (NaCl) transport and heat transfer were both very accurately simulated in a single simulation. Analysis of flow velocities and streamlines showed that flow packages in a convection cell mostly follow a closed path such that there is little radial mixing. The approaches and results presented here can be used for interpretation, testing, and analysis of other simulation software of free thermohaline flow and transport.

How to cite: Graf, T., Basten, A., Cirpka, O. A., Neuweiler, I., Rahmann, M. A., and Spitzenberg, F.: Thermal and thermohaline variable-density flow and salt transport in a 2D flow tank: Experiments, visualization and modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9305, https://doi.org/10.5194/egusphere-egu24-9305, 2024.

EGU24-10790 | ECS | Posters on site | ERE2.7

Sustainable operation of a large BHE field considering groundwater flow and land cover changes 

Quan Liu, Finn Weiland, Peter Pärisch, Niklas Kracht, Sven-Yannik Schuba, and Thomas Ptak

Shallow geothermal energy has been widely used for heating and cooling buildings by combining borehole heat exchangers (BHEs) with heat pumps. In recent years, how to maintain the efficiency and sustainability of large BHE systems has received increasing attention. An effective way to address this issue is to develop site-specific models to accurately predict the economy, thermal efficiency, and environmental impacts of geothermal systems. However, site characteristics are often simplified or even ignored, such as complex groundwater flow induced by subsurface heterogeneity and non-homogeneous surface heat transfer due to various land covers. In this study, a BHE system model was developed based on collected site characteristics and thermal measurements during system operation. Firstly, groundwater flow in a heterogeneous subsurface was considered in the developed model, according to the regional hydrogeologic conditions and borehole logs. In addition, complex surface heat transfer influenced by solar radiation and land cover characteristics was incorporated. Thermal parameters of different land cover types are considered as time-varying parameters to account for neighboring land use changes. Finally, the hydraulic parameters in the developed model were calibrated by comparing simulations with the groundwater temperatures observed in the boreholes. Next, we plan to further validate the prediction capability of the developed model based on recent temperature observations. We will then discuss the importance of site characteristics in assessing the thermal efficiency and environmental impacts of the BHE system by comparing the results with those of simplified models. Forecasts of system economics for the next ten years will also be made based on the developed model and possible thermal energy management strategies.

How to cite: Liu, Q., Weiland, F., Pärisch, P., Kracht, N., Schuba, S.-Y., and Ptak, T.: Sustainable operation of a large BHE field considering groundwater flow and land cover changes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10790, https://doi.org/10.5194/egusphere-egu24-10790, 2024.

Thanks to generous subsidies, many residential buildings in the Czech Republic are being equipped with photovoltaic and solar thermal panels, heat pumps, and heat and electricity accumulation systems. Photovoltaic roofs generate considerable savings overall (>50% in typical domestic installations). However, in summertime, they produce substantial and highly variable overflows of electricity into the grid, even with the use of air conditioning and electric vehicles charging. This result in volatile and at times negative wholesale prices of electricity. Conversely, in wintertime, the production is insufficient to balance the load from heat pumps (which are replacing wood burning and gas heaters), thereby contributing to high electricity prices. Hot water tanks and electric batteries can compensate load imbalances on a daily scale only, whereas national-scale solutions relying on gravitational energy storage are not viable. In this context, distributed systems for the seasonal accumulation of energy in the form of heat seem in principle an attractive solution. These systems could use the underground space as a heat source or sink according to needs, exploiting soil layers that are deep enough to ensure stability against seasonal fluctuations in temperature propagating from the surface, but also sufficiently shallow to ensure reasonable costs of installation. In new constructions, heat exchangers could be embedded in foundations or installed in boreholes below common areas such as access roads, parking lots and gardens. Similarly, they could be fitted in already built-up areas, and scaled in such a way to maximise their efficiency without disturbing the mechanical stability and performance of existing buildings and infrastructures. In the Czech Republic, despite a growing bottom-up demand for the creation of energy communities, their technical and regulatory viability remains unexplored. This is especially true for shallow underground seasonal thermal energy storage systems. In part, this relates to an insufficient knowledge of the ground response to thermo-hydro-mechanical forcing, as well as of possible ground-structure interactions. We are beginning to tackle this problem in upcoming research projects. Here, we will discuss our understanding of matters of priority to be addressed in our national context and present preliminary calculations demonstrating the potential of solutions at various scales.

How to cite: Scaringi, G.: Seasonal underground thermal energy storage for district heating and cooling in the Czech Republic: potential and challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10816, https://doi.org/10.5194/egusphere-egu24-10816, 2024.

EGU24-11181 | ECS | Orals | ERE2.7

Optimizing Energy Quay Walls: Insights from Comprehensive Thermal Analysis and Turbulent Flow Enhancement 

Marco Gerola, Francesco Cecinato, Jacco K. Haasnoot, and Philip J. Vardon

In recent decades, there has been a notable rise in the utilization of the subsurface as a source for heating and cooling through shallow geothermal installations. This trend is exemplified by the emergence of Energy Geostructures (EGs), an innovative technology that not only provides structural support to the ground or buildings but also facilitates the exchange of heat with the subsurface. EGs offer versatile applications for various energy needs, including their integration with ground source heat pumps for space heating, cooling, and domestic hot water provision.

Energy Quay Walls (EQWs) represent a promising type of energy Geostructures that demonstrate a unique ability to exchange heat with both the surrounding soil and open water. Despite the considerable potential for energy efficiency that EQWs hold, their limited implementation underscores the need for extensive research to comprehend their thermal behavior.

This study conducts an in-depth examination of EQWs, employing two Finite Element numerical models to reconstruct the undisturbed temperature profile within the soil and conduct a detailed 3D analysis of heat exchange processes in an EQW application. These models are validated using real data obtained from a full-scale test in Delft, The Netherlands. The results emphasize the significance of transitioning from laminar to turbulent flow regimes within the heat exchanger pipes, showcasing improved energy extraction efficiency, particularly from the open water layer.

Moreover, the study underscores the critical role of open water movement in the energy extraction process. This finding emphasizes the dynamic nature of open water in contributing to the overall effectiveness of EQWs as an EG. The study's outcomes provide important considerations for optimizing the design and implementation of EQWs, pointing towards the benefits of promoting turbulent flow regimes within the heat exchanger pipes and emphasizing the advantages of harnessing energy from actively moving open water layers. As the implementation of EQWs continues to expand, these insights contribute to advancing our understanding and enhancing the energy efficiency of this innovative technology. 

How to cite: Gerola, M., Cecinato, F., Haasnoot, J. K., and Vardon, P. J.: Optimizing Energy Quay Walls: Insights from Comprehensive Thermal Analysis and Turbulent Flow Enhancement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11181, https://doi.org/10.5194/egusphere-egu24-11181, 2024.

EGU24-11234 | Orals | ERE2.7

Delineation of the thermal plume associated with a standing column well system 

Laurence Champagne-Péladeau and Philippe Pasquier

Due to their potential for reducing energy consumption and greenhouse gas emissions, ground heat exchangers (GHE) coupled with heat pumps are now more commonplace. In urban areas, interference between neighboring GHEs can be a cause for concern, as it can affect average ground temperature and the long-term efficiency of heat pumps. Standing column wells, which use groundwater as a heat transfer fluid, are particularly suited to urban contexts as they do not require a productive aquifer or large areas of land. Unlike open-loop systems, groundwater is mainly recirculated in SCWs. However, to improve their performance, a fraction of the recirculation flow can be diverted to an injection well (IW), enabling the development of a thermal plume around the SCW and IW. Therefore, the delineation of the thermal plume for SCW systems is important to prevent environmental disturbances and maintain their thermal efficiency. A case study is conducted on a real system consisting of five SCWs and one IW installed in a productive fractured aquifer in the city of Mirabel, Canada. Using a 25-day hydraulic tomography, geophysical logs, drilling reports and thermal profiles, a 3D numerical model coupling heat transfer and groundwater flow was developed and calibrated. Using this calibrated model, numerical simulations were used to generate a 3D thermal plume and assess the environmental impact of the SCW system. The results indicate that the impact of SCW on this particular aquifer is limited, and that the system alone can be operated for 10 years without significant loss of efficiency or environmental impact.

How to cite: Champagne-Péladeau, L. and Pasquier, P.: Delineation of the thermal plume associated with a standing column well system, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11234, https://doi.org/10.5194/egusphere-egu24-11234, 2024.

EGU24-12616 | ECS | Posters on site | ERE2.7

Geophysical surveys to inform heat-flow experiments in a fractured chalk aquifer, Berkshire, UK 

Katerina Kyrkou, Adam Booth, Yin Jeh Ngui, Jonathan Chambers, Fleur Loveridge, Joseph Kelly, Emma Smith, Andy Nowacki, Edward Hough, David Boon, and Oliver Kuras

Urban geothermal solutions to heating and cooling have developed slowly in the UK, partly due to limited understanding of subsurface heat flow regimes and how stored heat might be sustainably governed within heterogeneous aquifers. Understanding heat flow through various aquifers is the goal of the SmartRes project, in which heat flow trials will be conducted in a number of sites. To provide context for heat flow experiments in a fractured chalk aquifer, geophysical surveys were acquired at Trumplett’s Farm, a groundwater abstraction and monitoring site near Reading (Berkshire, UK). Here, groundwater flow is primarily within a fracture network, likely in an active zone within the upper 10 m of the saturated chalk.

 

Seismic surveys recorded energy generated with an impact source at surface geophones (24 cabled GEODE, and 20 nodal Smart-Solo, geophones) and hydrophone strings, deployed to 100 m depth in boreholes drilled at the site. Smart-Solo nodes were deployed in a ~10 x 5 m grid at the site, with cabled geophones occupying lines between adjacent boreholes, with geophone intervals of up to 2 m. Nodal geophones recorded passively throughout the 3-day deployment and will be analysed using ambient noise correlation to evaluate anisotropy. The remaining data has been used for preliminary analysis with MASW (Multichannel Analysis of Surface Waves), P-wave refraction velocities, and vertical seismic profiles (VSPs).

 

 

MASW analyses suggest shear wave velocity (Vs) ranges from 250-600 m/s in the uppermost 1.5 m, but estimates are challenging given poor dispersion imaging of the fundamental mode. Different source-receiver offsets were tested to eliminate mode superposition, but the best dispersion curves are observed for zero-offset shots. Data were processed in a commercially available software with relatively limited freedom to adjust inversion parameters, hence further analysis will use the MuLTI code to undertake a constrained Monte Carlo inversion approach. The deeper structure of the chalk was characterised in VSPs, indicating reflective P-wave horizons at 52 and 69 m depth, separating material with interval velocities of ~2100 m/s, ~2500 m/s and 3000 m/s. Observing these reflections required aggressive frequency-wavenumber filtering to suppress direct waves in the water column.

 

Electrical resistivity tomography (ERT) surveys were conducted using the BGS PRIME ERT system to optimise array configuration for long-term monitoring. The reconnaissance survey included in-hole, borehole-to-surface, and surface ERT at 1 m intervals, employing C1P1-C2P2 bipole-bipole and dipole-dipole arrays around the site. Preliminary ERT inversion revealed low resistivity zones within the top 1.5 – 2 m across the site and mapped a potential south-dipping high resistivity structure. A longer ERT survey spread is planned to better reveal hydrodynamic interactions at deeper depths.

 

This initial insight will be refined with a fibre-optic distributed acoustic sensing deployment at the Trumplett’s site and an optimised repeat of the BGS PRIME ERT array. These will be synchronous with a thermal response test at the Trumplett’s site monitored with distributed temperature sensing.

 

Keywords: Seismic analysis, ERT, geothermal investigation, fractured aquifer, aquifer thermal energy storage

How to cite: Kyrkou, K., Booth, A., Ngui, Y. J., Chambers, J., Loveridge, F., Kelly, J., Smith, E., Nowacki, A., Hough, E., Boon, D., and Kuras, O.: Geophysical surveys to inform heat-flow experiments in a fractured chalk aquifer, Berkshire, UK, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12616, https://doi.org/10.5194/egusphere-egu24-12616, 2024.

EGU24-13401 | Posters on site | ERE2.7

Construction cost evolution of standing column wells in the area of Montreal, Canada. 

Alexandre Courchesne and Philippe Pasquier

Thanks to its role as a catalyst for geothermal projects using standing column wells (SCW), the geothermal research team at Polytechnique Montréal has been able to monitor and significantly influence drilling costs. Based on monitoring of drilling costs over a period of eight years, this presentation aims to share the strategy adopted and the means taken to reduce SCW costs in the Montreal region, Canada. As SCWs were little known in Montreal about ten years ago, drilling contractors tended to offer high prices for their construction. Discussions with contractors showed that these high costs included a significant safety margin, proportional to the risk perceived by the contractor. To change the perception of drilling contractors, our team then produced and made public plans & specifications, as well as drilling speeds and geological logs for SCWs up to 500 m deep. This strategy allowed for the public sharing of geological conditions on the island of Montreal, which reduced uncertainty for drilling contractors. In less than eight years, drilling costs have fallen from over $1,500 CAD per meter to approximately $160 CAD per meter for SCW of 500 meters. For institutional projects, we have found that the cost of SCWs now represents only 7% of the total cost of a renovation project where oil heating is replaced with a geothermal system using hydroelectricity.

How to cite: Courchesne, A. and Pasquier, P.: Construction cost evolution of standing column wells in the area of Montreal, Canada., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13401, https://doi.org/10.5194/egusphere-egu24-13401, 2024.

EGU24-14738 | ECS | Orals | ERE2.7

Measuring the thermal conductivity of sandstones 

Anna Albers, Fabien Koch, Kathrin Menberg, Hagen Steger, Christina Fliegauf, Linda Schindler, Sascha Wilke, Roman Zorn, and Philipp Blum

The sandstones of the Middle and Upper Buntsandstein are suitable host rocks for the installation of shallow geothermal systems due to their high thermal conductivities typically ranging between 1.9 to 4.6 W m-1 K-1 (Verein Deutscher Ingenieure 2010). Knowledge of the effective thermal conductivity is crucial to efficiently dimension borehole heat exchanger (BHE) systems. The standard method for determining effective thermal conductivities at a site is the thermal response test (TRT). However, thermal conductivity can also be analysed in the laboratory from core samples. In addition, various prediction models for the estimation of thermal conductivity based on lithological properties, such as porosity, exist. In this study, depth-specific thermal conductivities of sandstone samples of the Upper and Middle Buntsandstein are comprehensively analysed by applying different methods. First, thermal conductivities of about 140 core samples are analysed in the laboratory, and relations between material properties, such as porosity and mineralogy, and thermal conductivity are investigated. Furthermore, common prediction models are applied, and in addition, the measured and estimated thermal conductivities are compared to the effective thermal conductivities evaluated with an enhanced thermal response test (ETRT). The average effective thermal conductivity analysed with the ETRT is 4.7 W m-1 K-1, while the thermal conductivities analysed in the laboratory on saturated core samples range between 2.7 to 6.4 W m-1 K-1 with an average value of 4.6 W m-1 K-1. The best estimate from the prediction models is achieved by the Voigt-Reuss-Hill model with an average error of 13 % and a maximum error of 26 %. Overall, prediction models that assume a random distribution of solid and fluid components can achieve reliable estimates of the thermal conductivity of the sandstone. Thus, the results demonstrate that laboratory analyses can provide representative values of the effective thermal conductivities at a site with negligible or low groundwater flow. However, we also show that in order to achieve a representative value a sufficient number of samples has to be analysed, which entails high expenses for laboratory analyses.

Verein Deutscher Ingeniere. VDI 4640, part 1: Thermal use of the underground, fundamentals, approvals, environmental aspects, 2010.

How to cite: Albers, A., Koch, F., Menberg, K., Steger, H., Fliegauf, C., Schindler, L., Wilke, S., Zorn, R., and Blum, P.: Measuring the thermal conductivity of sandstones, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14738, https://doi.org/10.5194/egusphere-egu24-14738, 2024.

EGU24-15138 | Orals | ERE2.7

The thermoroad - full-scale demonstration of geothermal 5th generation district heating and cooling combined with sustainable urban drainage 

Søren Erbs Poulsen, Kristoffer Bested Nielsen, and Karl Woldum Tordrup

The thermoroad combines a 5th generation district heating and cooling (5GDHC) grid with a sustainable urban drainage system (SUDS) by utilizing the roadbed for surface water retardation and as a geothermal energy source. The porous roadbed is hydraulically separated from the surrounding soil by a bentonite membrane and is able retain approximately 150 mm of infiltrating surface water when fully drained. Water is drained to the roadbed through drain grates and the roadbed is then drained to the sewer by embedded drainage pipes. The drainage pipes connect to a water brake that restricts maximum water flow to the sewer to 0.78 l/s. Therefore, water is prevented from overloading the sewer in case of extreme precipitation. Instead, the water accumulates in the roadbed and is safely drained to the sewer later. 1200 m of geothermal piping is embedded in the roadbed, separated in two groups on the manifold. A further 3 borehole heat exchangers have been established serving as backup and heat sink for cooling in the summer. A single 100 m long 40 mm 1U pipe has been placed below the central wastewater pipe at a depth of roughly 2.5 m, to harness the waste heat. Once commissioned, 12 single family houses are supplied with surface water management in addition to heating and cooling by ground source heat pumps connected the 5GDHC grid. The system is fully monitored, with energy meters on the brine side of the heat pumps and on the geothermal sources in addition to compiled weather station data from the field site. Model analysis of operational data from the first prototype of the thermoroad, shows that the energy extraction from the geothermal pipes in the roadbed is increased by 56% from the drainage of surface water. The thermoroad is an example of integration of the energy and water sectors where synergies are created. The project consortium has built the second prototype of the thermoroad in full scale and for real consumers near Horsens in central Jutland, Denmark. The thermoroad is commissioned in February 2024. We present the engineering approach behind the thermoroad and the first experience with commissioning of the system.

How to cite: Poulsen, S. E., Nielsen, K. B., and Tordrup, K. W.: The thermoroad - full-scale demonstration of geothermal 5th generation district heating and cooling combined with sustainable urban drainage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15138, https://doi.org/10.5194/egusphere-egu24-15138, 2024.

The Climate Change (Emissions Reduction Targets) (Scotland) Act 2019 demands a net zero economy in Scotland by 2045, yet in the same year over three quarters of domestic heating was met by natural gas. A novel method and dynamic map resource is developed to visualise low enthalpy geothermal potential for space heating on a community scale using Ground Source Heat Pumps (GSHPs) and District Heat Networks (DHNs). This resource is intended to provide a screening tool that enables communities and policy makers to effectively reduce carbon emissions by aiding early-stage decision making and understanding of geothermal potential within the context of their communities. 

ArcGIS software is used to infer geothermal potential in 49,768km2 of superficial deposits (64% of total land area), in Scotland, using a Favourability Index (FI) and a 1km2 grid. Cells are assigned an FI value (0.0 - 5.0) using ten metrics based on key criteria: 1) deposit coverage, 2) thickness, 3) aquifer productivity, 4) temperature, 5) ground conditions, 6) heat demand, 7) protected land. Map resources developed show lowland areas generally exhibit more favourable conditions particularly within the Midland Valley, and settlements predominantly lie in high favourability areas. ~60% of the population is identified as living in areas where further investigations into community scale GSHPs is warranted, suggesting that the thermal resource held in unconsolidated sediments has significant potential to decarbonise the Scottish heating sector.

How to cite: Roberts, T. A., Hartley, A., and Bond, C.: Visualising low enthalpy geothermal favourability in Scotland: A map-based screening tool for community scale open-loop ground source heat pumps in superficial aquifers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15820, https://doi.org/10.5194/egusphere-egu24-15820, 2024.

EGU24-16026 | Orals | ERE2.7

Supporting deployment of mine water geothermal in disused coalfields with high-resolution datasets from a highly instrumented geoenergy observatory 

Andres Gonzalez Quiros, Alison Monaghan, Vanessa Starcher, Kyle Walker-Verkuil, David Boon, Paul Wilkinson, Jafar Al-Jawad, Mylene Receveur, Donald John MacAllister, and Oliver Kuras

Flooded disused mines have significant potential to supply clean heating and cooling and for seasonal storage in areas that could continue benefiting from the mines after closure. A proved technology, a more widespread deployment of mine water geothermal development is hampered by technical, socio-economical, and regulatory challenges. Among the technical challenges, the long-term system behaviour is an uncertain but fundamental element, regarding both the groundwater flow and heat distribution in the subsurface aquifer and the optimal performance of the geothermal installation and its components. A further development of mine water geothermal requires information and data from pilot, commercial and research installations to improve the knowledge about these complex systems, understand the interaction with the surrounding environment and learn from the experiences towards a more optimal design and construction of the geothermal infrastructure.

The UK Geoenergy Observatory (UKGEOS) in Glasgow was built between 2019 and 2023 as an at-scale research facility to study mine water geothermal. The observatory includes five boreholes drilled and screened into two levels of mine workings, four of them equipped with pumps and valves to allow for multiple configurations of abstraction and reinjection with operational pumping rates up to 12 l/s. The mine water boreholes are also equipped with hybrid fibre-optic cables for distributed temperature sensing (DTS) and electrical resistivity tomography (ERT) sensor arrays. The monitoring capabilities are complimented with an additional non-screened mine borehole, also equipped with DTS and ERT, and five environmental boreholes screened into the bedrock and the superficial aquifer to monitor the hydrogeological and thermal responses in the surrounding aquifers. The geothermal installation includes a sealed pipe between the abstraction/reinjection boreholes, three heat exchangers that can be used independently to test their performance, and a 200-kW heat pump/chiller. The system is equipped with sensors in the geothermal pipe circuit, the wellhead and downhole for high temporal resolution monitoring of hydraulic and thermal changes during the use of the Observatory and under natural conditions.

In this work we present results from some of the first geothermal tests performed in the Observatory in 2023. These include abstraction-reinjection in both heating and cooling modes with multiple configurations and variable flow rates and reinjection temperatures taking advantage of the capabilities of the Observatory. The datasets have been processed and examined with the support of numerical modelling. The analysis of hydraulic and thermal data from the multiple sensors in the mine and monitoring boreholes, the DTS and ERT, and the geothermal installation before and after heat exchange and reinjection have provided further insights about short- and long-term responses of the system. The observations show the different temporal and spatial scales of the hydraulic and thermal responses to the use of the geothermal infrastructure that constitute valuable information for the design of new geothermal installations in disused mines. The Observatory is now operative and open to academic and research projects aiming to understand better mine water systems.

How to cite: Gonzalez Quiros, A., Monaghan, A., Starcher, V., Walker-Verkuil, K., Boon, D., Wilkinson, P., Al-Jawad, J., Receveur, M., MacAllister, D. J., and Kuras, O.: Supporting deployment of mine water geothermal in disused coalfields with high-resolution datasets from a highly instrumented geoenergy observatory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16026, https://doi.org/10.5194/egusphere-egu24-16026, 2024.

EGU24-16515 | ECS | Posters on site | ERE2.7

Best practices for the sustainable management of the shallow geothermal energy resource in urban areas: insights from the case study of the City of Milan 

Alberto Previati, Alberto Presta Asciutto, Valerio Silvestri, and Giovanni Crosta

Recent EU directives and national regulations have encouraged the development of shallow geothermal energy as a renewable, low-emission source. Many cities in Europe are located in suitable areas with high geothermal potential and are therefore experiencing strong growth in the application of this technology for heating/cooling. On the other hand, densely populated urban areas experiencing a rapid development of shallow geothermal applications require appropriate tools to monitor and model the associated effects on both the quality and quantity of the available resource.

This work presents the case study of the metropolitan area of Milan, where the total number of geothermal wells (GWHP) has increased significantly in the last 5 years, covering a total thermal energy demand (including heating and cooling) from about 40 to 400 GWh/a. This very rapid growth and the resulting criticalities motivated the technical agencies and the stakeholders to improve the management of the shallow geothermal resource, which was addressed in the following steps.

1) Define common requirements for the development of a database of shallow geothermal installations, including the hydraulic and thermal regimes of the systems, and identify essential monitoring objectives for a better management of the subsurface low enthalpy thermal resource;

2) Study the cumulative impact of the existing geothermal systems in the entire Milan metropolitan area, delineating thermal capture and thermal disturbance zones using large-scale analytical and numerical models;

3) Assess the hydrogeological and subsurface thermal budgets on a regular grid basis to highlight the most critical areas in terms of hydrogeological (due to systems without groundwater reinjection) and thermal stresses (due to highly thermally unbalanced configurations).

The development of these tools and the implementation of a semi-automatic updating procedure aim to streamline the management of new requests with a quantitative view of the current exploitation of the geothermal resource in the Milan metropolitan area. Moreover, the implementation of future demand scenarios will improve the sustainability and reduce the risks of existing and planned systems.

How to cite: Previati, A., Presta Asciutto, A., Silvestri, V., and Crosta, G.: Best practices for the sustainable management of the shallow geothermal energy resource in urban areas: insights from the case study of the City of Milan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16515, https://doi.org/10.5194/egusphere-egu24-16515, 2024.

EGU24-16517 | Orals | ERE2.7

Heating and cooling with aquifer thermal energy storage (ATES) in cities 

Philipp Blum, Haegyeong Lee, Kathrin Menberg, and Ruben Stemmle

Aquifer thermal energy storage (ATES) is a promising technology for sustainable and climate-friendly space heating and cooling which can contribute to lower greenhouse gas (GHG) emissions. Using 3D heat transport models, this study quantifies the technical potential of shallow low-temperature ATES in the city of Freiburg, Germany. The numerical models consider various ATES configurations and different hydrogeological subsurface characteristics relevant for the study area. Based on the modeling results, spatially resolved ATES power densities for heating and cooling are determined and compared to the space heating and cooling energy demands. High ambient groundwater flow velocities of up to 13 m d-1 cause relatively high storage energy losses resulting in maximum ATES power densities of 3.2 W m-2. Until now, these still reveal substantial heating and cooling energy supply rates achievable by ATES systems. While heating supply rates of larger than 60 % are determined for about 50 % of all residential buildings in the study area, the cooling energy demand could be supplied entirely by ATES systems for 92 % of the buildings. In addition, ATES heating alone could result in greenhouse gas emission savings of up to about 70,000 tCO2eq a‑1. The proposed modeling approach in this study can also be applied in other urban areas with similar hydrogeological conditions to obtain estimations of local ATES supply rates and support city-scale energy planning for heating and cooling.

How to cite: Blum, P., Lee, H., Menberg, K., and Stemmle, R.: Heating and cooling with aquifer thermal energy storage (ATES) in cities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16517, https://doi.org/10.5194/egusphere-egu24-16517, 2024.

EGU24-16828 | ECS | Orals | ERE2.7

A case study on the use of AI methods towards bridging the gap between design and operation of ground-source heat pump systems. 

Nikolas Makasis, Monika Kreitmair, Chaoqun Zhuang, Kathrin Menberg, Wonjun Choi, and Ruchi Choudhary

Shallow geothermal energy technologies have seen significant development over past decades and the number of ground-source heat pump (GSHP) installations has seen an increasing trend worldwide. Importantly, a plethora of scientific research has explored performance, mechanical stability, optimisation, and innovative approaches to utilise the ground as a source or sink of thermal energy. Despite this, however, there is often a gap between the designed performance of a system and the realised in-situ operation. Such a gap can result from a lack of information, such as imprecise ground profile/thermal properties, changes in the environment and conditions, such as in building usage due to changes in behavioural patterns, as well as the fact that GSHP design is typically undertaken in isolation of other system elements, e.g., by using only estimates of the heating and cooling demands.

Real-time monitoring and appropriate smart control methods can help bridge this discrepancy, alleviating potential issues. Heat pumps and building management systems typically record useful data, such as the temperature of the fluid in the ground loop, constituting valuable sources of information on the current system performance at a given moment. However, using these data to predict how the system will perform in the future, and thus inform system operation, is not trivial. A field that can help tackle this problem is data science, which uses data-driven artificial intelligence (AI) approaches to provide useful insights from data and has had tremendous advancements in recent years. It is therefore expected that statistical AI approaches can be used with data from GSHP systems meaningfully, to inform the efficient operation of the system.

This research focuses on a case study in Cambridge, UK, where a GSHP system, with capacity of 320 kW and a ground loop with 24 160-m deep boreholes, provides heating and cooling for a recently constructed university building. The data recorded from this system is utilised together with a combination of AI methods, such as gradient boosting and deep neural network predictive models, and finite element modelling to assess how well the ground loop performance can be predicted in real time and the implications this can have on the performance of the system. Thus, this work demonstrates how GSHP data can be leveraged to make useful decisions based on updated information and thereby ensure that a GSHP system performs efficiently throughout its lifetime.

How to cite: Makasis, N., Kreitmair, M., Zhuang, C., Menberg, K., Choi, W., and Choudhary, R.: A case study on the use of AI methods towards bridging the gap between design and operation of ground-source heat pump systems., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16828, https://doi.org/10.5194/egusphere-egu24-16828, 2024.

EGU24-16846 | ECS | Orals | ERE2.7

Demonstration of a city-scale geothermal resource assessment using a statistical archetypes-based approach 

Monika Kreitmair, Nikolas Makasis, Kecheng Chen, Ruchi Choudhary, and Kenichi Soga

Growing demand for space in urban areas is accelerating the utilisation of the shallow subsurface for residential and commercial spaces, transport systems, industrial processes, and energy applications. The associated underground infrastructure can act as a source and sink of heat within the subsurface, altering the ambient temperature of the soil. The extent and magnitude of such a temperature anomaly is affected by the type and density of the structures in the ground, the environmental hydraulic conditions governing groundwater flow, and the geological properties impacting conductive heat transfer. As a result, temperature distributions will vary spatially beneath a given city, thereby also affecting the geothermal potential available for heating and cooling. Knowledge on where the greatest geothermal potential lies within a city can be crucial for large-scale planning of geothermal systems, and incorporating these within building and district-level systems.

We present a methodology to map the geothermal potential under cities, extending on a recently developed and published large-scale subsurface temperature modelling methodology, which statistically identifies commonalities in how natural and anthropogenic features affect subsurface heat transfer and creates subsurface archetypes. The extension entails incorporating ground heat exchanging structures, e.g. boreholes, within the archetypes to further subdivide existing thermal archetypes into geothermal archetypes and thus enable comparison of the relative performance of a ground heat exchanger in different areas of a city. The methodology is applied to the city of Cambridge, UK to generate a map of geothermal potential. Additionally, the demand for the city, computed using field data, is mapped to produce a demand-to-capacity map of the city. By exploring different exploitation scenarios of the geothermal potential, i.e. first-come-first-served vs. co-ordinated, we further determine the ability of the resulting deployment patterns to meet likely changes in future demand under the effects of climate change.

How to cite: Kreitmair, M., Makasis, N., Chen, K., Choudhary, R., and Soga, K.: Demonstration of a city-scale geothermal resource assessment using a statistical archetypes-based approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16846, https://doi.org/10.5194/egusphere-egu24-16846, 2024.

EGU24-16880 | ECS | Orals | ERE2.7

Is temperature a key driver of microbial community composition in urban shallow groundwater? – A case study from Vienna 

Angela Cukusic, Clemens Karwautz, Constanze Englisch, Eva Kaminsky, Cornelia Steiner, Christine Stumpp, and Christian Griebler

Increasing urbanization puts pressure on urban subsurface temperatures and the impact on groundwater quality and human health. However, consequences of the subsurface urban heat island phenomenon, i.e. heat anomalies due to the urban lifestyle, on groundwater ecosystems have rarely been addressed to date. Of particular interest are microorganisms, who are omnipresent in groundwater and intimately involved in the cycling of carbon and nutrients, the (im)mobilization of metals, the natural attenuation of contaminants, and providing essential ecosystem services. In the framework of the research project ‘Heat below the City’, 150 groundwater wells located in the city of Vienna were sampled twice, once in spring and once in autumn 2021. A multitude of physical-chemical and biological parameters of the groundwater samples were analyzed, including the characterization of the microbial community via 16S rDNA amplicon sequencing. Groundwater temperature, combined with other stressors, such as organic and inorganic pollutants, as well as lack of dissolved oxygen, was hypothesized to prominently impact the composition, diversity and activity of microbial communities. The results revealed a complex interplay of hydrogeological and physico-chemical conditions and microbial community parameters. Microbial diversity and activity showed both increasing and decreasing trends with increasing groundwater temperature, depending on the hydrogeological aquifer type. The dominant microbial taxa were not directly impacted by the observed temperature gradients. The number of heat sources in the vicinity of a sampling well explained microbial community composition better, than any specific heat source alone. Current attempts to explore urban groundwater microbial communities of Berlin and Munich are being pursued, with the aim to improve the fundamental understanding of the relationship between hydrogeology and pressures from urbanization on the groundwater microbiome.

How to cite: Cukusic, A., Karwautz, C., Englisch, C., Kaminsky, E., Steiner, C., Stumpp, C., and Griebler, C.: Is temperature a key driver of microbial community composition in urban shallow groundwater? – A case study from Vienna, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16880, https://doi.org/10.5194/egusphere-egu24-16880, 2024.

EGU24-18386 | ECS | Orals | ERE2.7

Integration of a seasonal borehole thermal energy storage into a transformed cooling network  

Felix Schumann, Nikolai Konenenko, and Tomás Fernandez-Steeger

A rapid decarbonisation of the heating and cooling sector requires accelerated retrofitting of buildings, increased use of renewable energy and waste heat utilisation (European Commission, 2016). From 2023, the German Heat Planning Act will legally mandate this development for cities and municipalities, with a special obligation to utilise unavoidable waste heat (BMWSB, 2023). In the transformation of future heating and cooling networks, a synergy of different energy sources is crucial, whose complementary strengths and weaknesses must be coordinated. A holistic concept for the future heating and cooling supply at campus level has been developed in cooperation with various disciplines from the fields of energy technology, building energy technology and engineering geology at the TU Berlin, using the university campus in Berlin-Charlottenburg as a example. Key components of the concept include load shifting between buildings, heat recovery from data centres and process cooling, expansion of a cooling network and the use of chillers as heat pumps during the heating season (Stanica et al, 2022).

The project also investigated the use of a seasonal geothermal energy storage system. The hydrogeological and urban planning parameters support the use of a borehole thermal energy storage (BTES). The subsurface is characterised by glacial fluvial sands and clays from the last ice ages, which have high thermal conductivity and capacity. The groundwater temperature is approximately 12°C and the subsurface has a very low groundwater flow velocity, which favours a high efficiency of the BTES. On the North Campus there is a 12,900 m² open space that can accommodate about 130 heat exchangers and has a heat storage capacity of about 1.2 GWh/a.

The cooling demand for the North Campus is approximately 4.7 GWh/a. The cooling systems are to be supported by free cooling at outdoor temperatures below 0°C and by the BTES at temperatures above 0°C. The special point here is that the so-called regeneration of the storage in summer is realised by the existing waste heat on the campus and not by solar thermal energy. This allows the available roof space for photovoltaic systems to be used to generate additional electricity for the operation of the individual systems. To operate sustainably and efficiently, the chillers require an inlet temperature between 6 and 12°C.

The dynamic interaction between the BTES and the associated heating and cooling system has a significant impact on the efficiency of such underground storage system. In order to optimise the design of the BTES and to ensure sustainable operation of all components, all systems were considered holistically and coupled with each other. The results of this study show that utilising the maximum amount of free space as storage in combination with the other cooling sources is not efficient. The storage capacity for the BTES is about 500 MWh/a. The use of the BTES has significantly increased the use of waste heat and reduced electricity consumption for the chillers by 200 MWh/a. In addition, 200 t of CO2 per year will be saved, which corresponds to a further increase of 20 %.

How to cite: Schumann, F., Konenenko, N., and Fernandez-Steeger, T.: Integration of a seasonal borehole thermal energy storage into a transformed cooling network , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18386, https://doi.org/10.5194/egusphere-egu24-18386, 2024.

The increasing energy prices and technological progress in ground source heat pumps (GSHP) in recent years has substantially propelled the use of shallow geothermal energy in Germany. With the swiftly growing numbers of installed GSHP in urban areas, the optimal and sustainable use of shallow geothermal resources requires a thorough analysis and understanding of the key components and physical processes involved in the underground at different spatial and time scales. In particular, the question of possible thermal and/or thermo-hydraulic interaction of neighboring small-power (<30kW) geothermal facilities typical of single-family houses is most relevant. We address this question within the framework of the ongoing joint research project WärmeGut by studying the efficiency of shallow geothermal heat recovery in terms of avoiding negative thermal or thermo-hydraulic interferences between neighboring installations.  

Using 3D finite-element numerical modelling and simulation, this work focuses on the impact that variably saturated flow and seasonably varying underground temperature have on several optimized pipe assemblage designs at different scales. Specially, we consider different shallowest-depth geothermal heat collector patterns and different soil thermal and hydrogeological properties. Taking into account the impact that varying saturation has on the soil thermal properties, we vary the location, depth, arrangement, pipes layout, and operational schemes to elucidate the controlling factors on the optimized sustainable use of shallowest-depth geothermal resources.

Employing COMSOL Multiphysics, we conduct a series of simulations intended to systematically analyze the complex thermo-hydraulic interaction between neighboring shallow geothermal installations under varying climatological conditions. Since there is no requirement by the German state geological surveys to provide any detailed modelling on the performance and thermal impact of small-power (<30kW) shallow geothermal facilities, we illustrate our simulation results in detail for a large range of parameter variation. We present in this work our most recent results.

This work is conducted within the joint research project WärmeGut "Flankierung des Erdwärmepumpen-Rollouts für die Wärmewende durch eine bundesweite, einheitliche Bereitstellung von Geoinformationen zur oberflächennahen Geothermie in Deutschland" and is financed by the German Federal Ministry for Economic Affairs and Climate Action (FKZ: 03EE4046B).

How to cite: Meneses Rioseco, E., Ravidà, D. C. G., Dussel, M., and Moeck, I. S.: Optimization of shallowest-depth geothermal heat collectors for sustainable energy production under variable saturation conditions and seasonal temperature fluctuations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19709, https://doi.org/10.5194/egusphere-egu24-19709, 2024.

EGU24-19869 | ECS | Posters on site | ERE2.7

Unravelling the shallow geothermal energy potential in Germany: a workflow for the realisation of national-scale harmonised site-suitability maps 

Domenico C.G. Ravidà, Ernesto Meneses Rioseco, Michael Dussel, and Inga S. Moeck

The successful realisation of climate protection and energy transition goals in Germany is contingent on an effective heat transition strategy. A key aspect of this strategy is to increase the use of shallow geothermal energy (SGE) resources for ground-sourced heat pump (GSP) applications. To date, however, the characterisation of the near-surface geothermal potential is highly heterogeneous across the country. The information is fragmented and discordant among its sixteen federal states, and it is often not readily accessible. These factors significantly challenge the achievement of the established goals of expanding SGE utilization.

This work is part of the ongoing WärmeGut project, which aims to i) assess geothermal potential and site-suitability for GSP applications across Germany, ii) compile, standardise and harmonise geoinformation on a national scale, and iii) bridge the (geo-)data accessibility gap by integrating SGE information into GeotIS – the well-established geothermal information system of Germany. Currently, GeotIS places emphasis on geological information for depths beyond 1500 meters. In this contribution, we present a concept and workflow developed for evaluating the near-surface geothermal suitability, which refers to the possibility of harnessing the SGE resource in designed areas by specific GSP applications (e.g., borehole heat exchangers, geothermal collectors and groundwater heat pumps). For a region to be deemed suitable, geothermal installations must not interfere with any existing land use. Furthermore, it is essential to assess the presence of specific geological conditions in the subsurface that can threaten the stability of geothermal systems and potentially endanger the balance of other natural resources and human activities.

In our workflow, the determination of geothermal suitability is based on the evaluation of a preliminary set of 38 conflict criteria, categorised into four groups: i) national and local regulations that identify conservation areas, ii) geological, iii) hydrogeological and iv) anthropogenic factors. For this purpose, we compile and integrate a vast array of data, encompassing publicly available databases, data from geological surveys, and newly generated information. Data includes, but is not limited to, geological and hydrogeological maps, 3D subsurface models, stratigraphic information, and chemical and physical measurements of rocks and groundwaters obtained from existing wells. We defined three suitability categories: areas unsuitable for SGE exploitation, areas with limited suitability due to risk conditions or land use conflicts, and areas generally suitable for SGE exploitation. These categories are depicted across the national territory using a traffic light colour scheme.

The preliminary site-suitability maps offer a glimpse into their role in the heating transition in Germany, serving as an essential instrument for showcasing the potential for SGE exploitation across the country. By bridging the current information gap and standardising geodata on a national level, traffic light maps are likely to become the foremost tool employed in the planning and designing of geothermal installations.

How to cite: Ravidà, D. C. G., Meneses Rioseco, E., Dussel, M., and Moeck, I. S.: Unravelling the shallow geothermal energy potential in Germany: a workflow for the realisation of national-scale harmonised site-suitability maps, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19869, https://doi.org/10.5194/egusphere-egu24-19869, 2024.

EGU24-20924 | ECS | Orals | ERE2.7

Standing column wells in cold climates: a case study in a highly productive aquifer 

Gabrielle Beaudry, Philippe Pasquier, Jasmin Faucher, Giulio Tonellato, and Michaël Kummert

Standing column wells (SCW) are ground heat exchangers that recirculate groundwater in a deep uncased borehole and “bleed” only a fraction of the pumped water during peak demand periods to boost advective heat transfer. While operational feedback collected from numerous systems in the northeastern United States is available and provides general design guidelines (Orio et al., 2005; 2006), practitioners have been slow to embrace SCWs outside their area of emergence. This reluctance can be explained in part by a lack of awareness, as well as lingering concerns about groundwater chemistry and the reliability of these systems in diverse climatic and geological settings. In this context, the present work presents a case study of a demonstration SCW system that was retrofitted in a school near Montreal, Québec, Canada, with the aim of sharing the knowledge gained during the design and commissioning phases.

The demonstration system’s design relied on an early exploratory phase, which included an exploratory drilling, a thermal response test, a pumping test, and groundwater analyses. These field operations first uncovered the presence of a highly productive sandstone aquifer, which 1) halted drilling early at 133 m due to the elevated water pressure, and 2) had a strong influence on the thermal response test’s results due to the high efficiency of advective heat transfer, even in the absence of bleed. Accordingly, the development and calibration of an advanced coupled thermo-hydrogeological numerical model was deemed necessary to evaluate the proper sizing of the ground heat exchanger.

Following design and construction, a review of the available data was conducted to evaluate the SCW system’s general performance metrics. This exercise first demonstrated its overall efficiency, which reduced drilling lengths by approximately 73%, construction time by 52%, and initial costs by 37% compared to conventional closed-loop boreholes. It was also found that the SCWs were able to sustain building loads over 200 W/m and to reduce peak electrical power demand by 71% compared to electric resistance heating, this on the coldest winter day when the air temperature was -26 °C. Monitoring of the pressure losses through the plate heat exchanger and step-drawdown tests did not indicate any immediate groundwater quality concerns. On the other hand, the elevated energy consumption of the pumping equipment affected the system’s seasonal performance factor, and a few operational issues related to corroded probes and inefficient control sequences compromised energy and financial savings and had to be resolved.

In conclusion, the results of this case study demonstrate the strong potential of SCWs for reducing the environmental and economic costs of heating operations in cold climates. The importance of conducting an early exploratory phase was emphasized, as well as the potentially significant impact of productive aquifers and groundwater flow on field testing, design studies and overall performance metrics. Lastly, it also became evident that careful selection of the pumping equipment and control sequences, as well as post-commissioning efforts, were necessary to ensure the optimal operation of this innovative technology.

How to cite: Beaudry, G., Pasquier, P., Faucher, J., Tonellato, G., and Kummert, M.: Standing column wells in cold climates: a case study in a highly productive aquifer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20924, https://doi.org/10.5194/egusphere-egu24-20924, 2024.

In urban areas, increased thermal use of the subsurface, including infrastructure development (e.g., tunnels and underground car parks) and adaptation strategies (e.g., more frequent thermal use of aquifers for "cooling" purposes or increased implementation of the sponge city concept), associated with global warming will inevitably increase urban groundwater temperatures. Likewise, anthropogenic adaptation strategies could have a greater impact than climate change itself.

In scope of the presentation strategies for the thermal management of urban groundwater resources in northwestern Switzerland are presented by discussing climate change, thermal potentials, and opportunities for adaptation measures. In particular, there are opportunities related to unused anthropogenic waste heat, especially in the subsurface of urban areas, and the energy potential that could be tapped through suitable construction measures.

How to cite: Epting, J.: Thermal management of urban groundwater resources - climate change, thermal potentials and opportunities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21533, https://doi.org/10.5194/egusphere-egu24-21533, 2024.

EGU24-21884 | ECS | Orals | ERE2.7

The Impact of Borehole Diameter on Loop Length and ThermalResistivity in Closed-Loop Ground Heat Exchanger System 

Sriparna Roy, Tanusree Chakraborty, and Jagdish Telangrao Shahu

Introduction: Geothermal heat pump systems GSHPs use the Earth’s subsurface as a heat source in winter and heat sink in summer. A GSHP system integrated with vertical HDPE U-loops for transferring the heat to and from the ground is called a closed-loop ground heat exchanger (CLGHE) system placed by drilling the boreholes. In this study, the relationship between borehole diameter, thermal resistance, and the optimum loop length of CLGHE
systems is investigated.
Methods: Utilizing the standard thermal line source equation, analysis of borehole thermal resistivity bR variations across a spectrum of borehole diameter d sizes (ranging from 80-180 mm) has been performed. The soil thermal properties like conductivity λ are considered as 1.5 W/mK , initial ground temperature is considered to be 25⁰C. The analysis is extended to evaluate the influence of borehole diameter sizes on the optimal length of geothermal single U-loops using Ground Loop Design (GLD) software. This comprehensive assessment incorporated critical factors such as soil thermal properties, heat transfer fluid characteristics, and U-loop pipe attributes which has been replicated from the analytical study for a heat load of 10MWh.
Results: The outcomes of our simulations revealed notable correlations: larger boreholes consistently demonstrated increased thermal resistance analytically. It has also been observed through the GLD simulations that the loop length increases as the borehole diameter increases for example: when the diameter increases from 80mm to 100mm the loop length increases from 57.6 to 56.5m for a geothermal grid of 2x2 rectangular configuration for the same soil properties and thermal loading conditions. The observed relationship holds implications for optimizing system design and performance, particularly in diverse soil conditions. In conclusion, our study contributes valuable insights into the thermal efficiency of GSHP systems, emphasizing the importance of borehole diameter in influencing overall energy transfer capabilities. These findings provide a foundation for further research and practical applications for the CLGHE systems.

How to cite: Roy, S., Chakraborty, T., and Shahu, J. T.: The Impact of Borehole Diameter on Loop Length and ThermalResistivity in Closed-Loop Ground Heat Exchanger System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21884, https://doi.org/10.5194/egusphere-egu24-21884, 2024.

EGU24-1522 | ECS | Posters on site | ERE2.9

Hydrochemical Indicators for Sustainable and Optimized Geothermal Use of Deep Groundwater  

Annette Dietmaier and Thomas Baumann

Geothermal heat and power generation are two of several competing uses of deep groundwater reservoirs. The stress state of these slowly regenerating systems is increasing as drinking water production from shallow resources suffers from anthropogenic influences: overexploitation, total depletion, and deterioration through anthropogenic contaminants are exacerbated by a climate change-induced failure to recharge. In contrast to shallow groundwater, deep aquifers are shielded from short-term influences, like contamination, by protective overlying strata. The groundwater age is generally much higher, indicating slow regeneration processes because the system is nearly closed in its natural state. Recent data, however, suggests that this assumption is not valid for many geothermal systems with high flow rates. Therefore, a careful assessment of all competing operations using deep groundwater reservoirs is required. It should focus on the interactions between different aquifers and those within the reservoirs, all leaving their marks on the waters’ hydrochemical composition.
The lack of dedicated monitoring wells around geothermal production and injection sites makes it difficult to quantify the development of these reservoirs’ flow patterns. Furthermore, regular complete analysis data are usually only available at long intervals of 12 months. Still, short-term flow path development is a crucial factor in assessing heat extraction efficiency. Impaired extraction due to preferential flow paths forming between production and injection sites will degrade overall operation efficiency.

Here, we challenge state-of-the-art practices for monitoring deep aquifers. Based on decades worth of hydrochemical data on groundwater extraction at both single-well operations and geothermal doublets, we discuss how hydrochemical signatures can help determine the grade of sustainability at which deep geothermal wells are operated. Acknowledging that these assessments depend on an adequate database, and that deep groundwater research is plagued by notorious data scarcity, we tested the application of virtual sensors to these wells was tested. Lab experiments complete the analysis, quantifying the kinetics of the fluid-matrix interactions between the injector and producer.

The outcomes of this dissertation include a statistically reproducible algorithm assessing how sustainably a well is operated, focusing on the inherent dynamics at play in deep groundwater. A series of regression analyses conclude that the databases associated with deep groundwater wells are still insufficient to train virtual sensors; however, they allow conclusions on the required minimum amount of hydrochemical analyses needed to adequately represent inter-seasonal fluctuations in the aquifer. Fluid-matrix interactions result in threshold values for hydrochemical changes, which serve as a trigger to review well operation strategies and to update hydraulic and thermal models. They also indicate that changes are likely following an increasing dynamic because the surface area available for reactions increases geometrically and in roughness. Our calibrated model shows that decreasing the injection temperatures and adding CO2 as a scaling inhibitor significantly increases the reservoir's reactivity.

Hydrochemical data can provide valuable insight into the flow processes in deep reservoirs, which are inaccessible otherwise. With smart sampling procedures and a tailored set of parameters, acquiring relevant data becomes feasible with relatively small financial investments.

How to cite: Dietmaier, A. and Baumann, T.: Hydrochemical Indicators for Sustainable and Optimized Geothermal Use of Deep Groundwater , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1522, https://doi.org/10.5194/egusphere-egu24-1522, 2024.

We develop a computation framework from scratch that allows us to conduct 3D numerical simulations of groundwater flow and heat transport in hot fractured reservoirs to find optimal placements of injection and production wells that sustainably optimize geothermal energy production.

We model the reservoirs as geologically consistent randomly generated discrete fracture networks (DFN) in which the fractures are 2D manifolds with polygonal boundary embedded in a 3D porous medium. The wells are modeled as line sources and sinks.
The flow and heat transport in the DFN-matrix system are modeled by solving the balance equations for mass, momentum, and energy.
The fully developed computational framework combines the finite element method with semi-implicit time-stepping and algebraic flux correction.
To perform the optimization, we use various gradient-free algorithms.

We present our latest results for several geologically and physically realistic scenarios.

How to cite: Partl, O. and Rioseco, E. M.: Optimization of geothermal energy production from fracture-controlled reservoirs via 3D numerical modeling and simulation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4164, https://doi.org/10.5194/egusphere-egu24-4164, 2024.

EGU24-4549 | ECS | Orals | ERE2.9

Geothermal Reservoir Deformation Monitoring Based on Coda Wave Interferometry 

Yunliang Wang, Jérôme Azzola, Dimitri Zigone, Olivier Lengliné, Vincent Magnenet, Jérôme Vergne, and Jean Schmittbuhl

Monitoring of geothermal reservoir deformation is essential for the normal development of the Enhanced geothermal system (EGS). Coda wave interferometry (CWI) with ambient noise is regarded as an effective and low-cost monitoring technique and draws more and more attentions. But the connection between the obtained CWI measurements and the undergoing physical changes of deep reservoir is still not so clear. In this study, we take Rittershoffen geothermal system (France) as a case study and conduct a series of forward simulations regarding the propagation of scattered wavefield through the deformed model considering acoustic-elastic effect based on Code_ASTER (mechanical loading) and SPECFEM2D (wave propagation). The simulations are based on a two dimensional numerical model with a scale of 12km (width)×20km (height), in which the upper reservoir model contains 8 layers to mimic Rittershoffen geothermal reservoir, the lower sub model with multiple circular inclusions is set to scatter the waves emitted from point source at bottom and produce scattered wavefield; two seismic stations are located at the top of the model. The model is first verified by reproducing the seasonal variation of relative wave velocity changes obtained from ambient noise cross-correlation functions (ANCCF) induced by the underground water table elevation changes. Based on the validated model, we study the effect of in-situ reservoir deformation on CWI measurements by modelling the hydraulic pressure increases on an open hole and the aseismic slip of an embedded fault which is based on the case of hydraulic injection of GRT-1 well, Rittershoffen. The result indicates the induced small reservoir deformation in both situations can be detected by CWI measurements, which helps us to have a better understanding about the connection between the obtained CWI measurements and the undergoing deformation of deep geothermal reservoir.

How to cite: Wang, Y., Azzola, J., Zigone, D., Lengliné, O., Magnenet, V., Vergne, J., and Schmittbuhl, J.: Geothermal Reservoir Deformation Monitoring Based on Coda Wave Interferometry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4549, https://doi.org/10.5194/egusphere-egu24-4549, 2024.

EGU24-6571 | ECS | Orals | ERE2.9

From seismic re-processing to mechanic modelling, a new interpretation of the TRANSALP seismic section as a base for future geothermal energy projects, lower Inn Valley, Tyrol, Austria 

Simon Hinterwirth, Hugo Ortner, Marcellus Schreilechner, Heinz Binder, Ewald Lüschen, Makus Jud, Stefan Hoyer, Magdalena Bottig, and Esther Hintersberger

In western Austria, especially in Tyrol, the potential for geothermal energy use is unexplored. The project GeoEN Inntal is aiming to determine this potential and the risks for the use of geothermal energy in a complex tectonic setting in the Inn valley. The valley is bordered by the Permo-Mesozoic sedimentary succession of the Northern Calcareous Alps in the north and the south-east, as well as Upper Austroalpine basement units in the south. Since the early Late Cretaceous, during Eoalpine orogeny, the Austroalpine basement and its Mesozoic cover were involved in nappe stacking and folding. The nappe stack was again refolded and faulted in the Palaeocene-Eocene collision of Adria and the European distal margin, as well as in Oligocene-Miocene, when post-collisional processes lead to an eastward extrusion of crustal blocks, out-of-sequence thrusting and the development of major faults. One of these faults is the Inntal shear zone, a sinistral ENE-trending shear zone, controlling the course of the Inn valley (“Inntal” in German). The shear zone has a multi-phase activity and is kinematically linked with the Brenner normal fault south of Innsbruck, the Alpine basal thrust at the Alpine front, and the Sub-Tauern ramp, rooting below the Tauern window. As the deep subsurface of the Inn valley was only explored geophysically, but no exploration boreholes were drilled, little is known about these structures at depth. Here we present the reprocessed Inntal part of the TRANSALP seismic section, which serves as a base for multidisciplinary modelling approaches. As part of the GeoEN Inntal project, we present first results from our 3D modelling of fault geometry, results from mechanical modelling of the Inntal shear zone, as well as first temperature gradient assessment from hydrological modelling.

How to cite: Hinterwirth, S., Ortner, H., Schreilechner, M., Binder, H., Lüschen, E., Jud, M., Hoyer, S., Bottig, M., and Hintersberger, E.: From seismic re-processing to mechanic modelling, a new interpretation of the TRANSALP seismic section as a base for future geothermal energy projects, lower Inn Valley, Tyrol, Austria, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6571, https://doi.org/10.5194/egusphere-egu24-6571, 2024.

EGU24-7499 | Orals | ERE2.9

Best practices in surface and subsurface natural fracture characterisation to advance carbonate geothermal reservoirs insights: a spotlight on the Geneva Basin, Switzerland.  

Pierre-Olivier Bruna, Jasper Hupkes, Myrthe Doesburg, Giovanni Bertotti, Andrea Moscariello, and Jérôme Caudroit

Naturally fractured geothermal reservoirs (NFGR) represent a challenging frontier for sustainable energy exploration and production. These reservoirs are characterised by the presence of complex fracture networks controlling hot fluid movement at depth. Unfortunately, these networks cannot be directly observed, and their properties need to be modelled. Classically, these models are based on statistic data obtained from outcrops and borehole data. Outcrops allow characterisation of the geometry of networks at a scale up to 100’s of meters. However, the analogy between surface and subsurface is not trivial and surprisingly, the notion that different fracture sets are genetically related is rarely used. Borehole core data provide the only direct sampling of the subsurface. However, cores are challenging and expensive to obtain. As an alternative, geophysical borehole images are acquired to observe fractures in the subsurface. However, the quality of these images is variable, making their interpretation uncertain. In this study, we aim to minimize the uncertainties related to fracture picking in borehole images to accurately recognise specific part of the network interpreted from the surrounding outcrops. This approach will provide new perspective in the characterisation of NFGRs.

We test our approach on the Geneva Basin, located in westernmost part of Switzerland. There, the Lower Cretaceous carbonate units are expected to host geothermal resources. Recently, an exploration well, GEo-01 was drilled in the Canton of Geneva to evaluate the geothermal potential of the Lower Cretaceous reservoir. The basin is bounded to the north by the Jura and to the south by the Saleve mountain and the Borne massif where the Lower Cretaceous rocks are outcropping. This area extends for about 1500 km2.

In these outcrops, we introduce the concept of discontinuity associations where sets of fractures, veins and stylolites which formed under a similar stress regime are grouped together. The characterisation of discontinuity associations allows to map the orientation of the maximal principal paleostress (σ1) of genetically related discontinuities. This method is a more robust way of reconstructing fracture-forming deformation events than assigning one deformation event per discontinuity set. We consistently identify three distinct associations over the investigated mountain ranges. Those associations are formed before the onset of fold-and-thrust belt and therefore constitute a background fracture network expected to be found in the targeted geothermal reservoir.

To prove this hypothesis, we looked for the same discontinuity associations in borehole images of GEo-01. This well disposes of a unique dataset of five independent interpretations of the same 122 m interval of Lower Cretaceous series. To quantify and reduce interpretation uncertainties, our study involves a comparative statistical analysis of these interpretations. The outcomes of this  analysis facilitate the identification of intervals where interpreters reached consensus and those where discrepancies emerged. We delved into the factors influencing interpretation agreement or divergence, considering fracture attribute variability, image log quality variation, and geology. We define guidelines to interpret fractures in the borehole images of the Lower Cretaceous of the Geneva Basin and ultimately validate the presence of the three discontinuity associations as background fractures in the geothermal reservoir.

How to cite: Bruna, P.-O., Hupkes, J., Doesburg, M., Bertotti, G., Moscariello, A., and Caudroit, J.: Best practices in surface and subsurface natural fracture characterisation to advance carbonate geothermal reservoirs insights: a spotlight on the Geneva Basin, Switzerland. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7499, https://doi.org/10.5194/egusphere-egu24-7499, 2024.

EGU24-8838 | ECS | Orals | ERE2.9

Influence of basement morphology on hydrothermal convection in the Upper Rhine Graben  

Rose-Nelly Ogandaga Capito and Dominique Bruel

The Upper Rhine Graben (URG) is the central segment of the European Cenozoic Rift System which is known for hosting some of Europe’s major geothermal anomalies. Historically, the region has been explored for its hydrocarbon resources and more recently the area has been targeted for deep geothermal energy. Since then, several heat and/or power plants have been commissioned and are currently in operation. However, despite the gradual development of the sector, the technical potential of the URG remains under-exploited. While the first deep geothermal projects benefited from thermal anomalies known at surface, new projects require costly exploration techniques to ensure a right combination of elevated temperature and sufficient permeability.

Several numerical modelling studies have attempted to reproduce thermal anomalies by integrating a complex three-dimensional geometry of the URG and assuming a topography-induced forced convection largely dominating free convection. As a result, the authors observe a basin-wide graben-perpendicular flow from the graben shoulders towards its center, with an upflow axis approximately below the Rhine River. These conclusions are in contrast to previous geochemical studies which suggest that deep brines discharged from the granitic basement are rather homogeneous on a large scale and have a common origine in deep Triassic sedimentary formations with temperatures close to 225 ± 25 °C. The brines would then migrate through sedimentary layers and permeable fault zones in the basement, from the center of the graben to its western flank, where they would flow up into horst structures such as Soultz or Landau. Moreover, this deep brine circulation in the central part of the graben is thought to be almost completely decoupled both from the circulation of less saline fluids in its upper part, in the Tertiary layers, and from flows along bordering faults, which would be characterized by a rapid recycling of meteoric water via deep circulation loops.

Here, we suggest that thermal anomalies in the French western border of the graben result from deep convective cells developing in the basement along the inclined basement-sediments interface without any help from external pressure forces. Therefore, we used the GeORG public database to build a simplified three-dimensional numerical model of the central part of the URG. Results are obtained using the OpenGeoSys software. Conceptual numerical experiments of thermo-hydraulically coupled simulations were carried out, assuming density-driven convective heat transport with thermal dependence of density and viscosity parameters. The first series of models were constructed without any faults, and we show that an integration of basement morphology, a depth-decreasing basement permeability and a fixed heat flow condition at the base of the model is sufficient to trigger multiple upwellings in the basement within a few million years. Current on-going work is to further calibrate the model to reproduce known existing temperature records and to observe how the integration of permeability heterogeneity or one or more fault zones can reorganize the convective system, thus allowing to trace an effective permeable pattern at larger scale. 

How to cite: Ogandaga Capito, R.-N. and Bruel, D.: Influence of basement morphology on hydrothermal convection in the Upper Rhine Graben , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8838, https://doi.org/10.5194/egusphere-egu24-8838, 2024.

EGU24-9960 | ECS | Orals | ERE2.9

An experimental demonstration of fault preconditioning for reduced seismic hazard 

Barnaby Fryer, Corentin Noël, Feyza Arzu, Mathias Lebihain, and François Passelègue

The mechanical stimulation of a fault or fracture in the case of an Enhanced Geothermal Reservoir (EGS) is generally reliant on inducing shear dilation of a targeted discontinuity. However, this same process can lead to the nucleation of a potentially-damaging seismic event. Here, a reservoir stimulation technique known as preconditioning is demonstrated experimentally for the first time. This technique consists of initially increasing the effective normal stress along the fault, in practice corresponding to a period of fluid production. Following this the fault is locally unloaded, corresponding to fluid injection. As the unloading continues, a slipping patch may form, eventually leading to dynamic rupture. However, the previously-induced high effective normal stress further along the fault acts as a fracture energy and reduced-stress-drop barrier, potentially resulting in rupture arrest. Here, a highly-instrumented (strain gauges, accelerometers, acoustic sensors, displacement sensors, load cells) biaxial apparatus is used to demonstrate this procedure, making use of the translucence of polymethylmethacrylate (PMMA) and a high-speed camera to image the development of propagating ruptures. It is demonstrated, as previously predicted from theory, that preconditioning has the ability to halt dynamic ruptures and may therefore be a viable stimulation technique resulting in reduced hazard in EGS stimulation. Specifically, experiments are performed at nominal normal stresses of 60, 90, and 120 bar, with preconditioning (or normal stress increase) corresponding to approximately 8, 16, and 24%; in addition to control cases with no preconditioning. Generally, preconditioning slows rupture propagation at 8% normal stress increase and completely halts it for larger values of preconditioning. It further results in a reduced shear stress drop, increased fracture energy, and reduced slip velocity. These results may one day have further implications for the potential of controlled stress release along natural faults.

How to cite: Fryer, B., Noël, C., Arzu, F., Lebihain, M., and Passelègue, F.: An experimental demonstration of fault preconditioning for reduced seismic hazard, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9960, https://doi.org/10.5194/egusphere-egu24-9960, 2024.

EGU24-10336 | ECS | Posters on site | ERE2.9

Bayesian Evidential Learning Approach to Uncertainty Quantification in THM Model of Geothermal Energy Extraction in Deep Mines 

Le Zhang, Alexandros Daniilidis, Anne-Catherine Dieudonné, and Thomas Hermans

Utilizing existing deep mining systems for geothermal extraction not only facilitates the development of geothermal systems but also helps meeting the cooling requirements for deep mining operations. In this study, a thermo-hydro-mechanical model of geothermal extraction in deep mines is developed to investigate the evolution of mine galleries stability and temperature, and the temperature changes in geothermal production wells. The uncertainty in system responses is predicted through the Bayesian Evidential Learning framework.

Due to our limited understanding of the material properties and the scarcity of measurement data, uncertainties emerge in the forward simulations. Ideally, a comprehensive uncertainty analysis would be conducted to predict all possible outcomes and assess any risks. However, In light of the intractability of performing comprehensive uncertainty analyses in scenarios with vast unknown data, particularly due to the computational overhead of multiple inverse problem-solving, we employ the Bayesian Evidential Learning framework, which provides a feasible and rapid alternative for approximating prediction post-distributions and choosing the most informative data sets. Before implementing BEL, we employed Latin Hypercube Sampling to create 500 sets of realizations for forward simulations, and subsequently utilized global sensitivity analysis to evaluate the data's informational value, aiming to diminish the uncertainty in predictions. In this paper, the BEL framework is utilized to achieve two: firstly, to stochastically predict the responses of the system (stability and temperature) within the BEL framework, using machine learning to discover direct correlations between predictors (sensitive parameters) and targets (system responses). Subsequently, newly collected data can be utilized to predict the approximate posterior distributions of the corresponding gallery stability, temperature, and production well temperature, thus circumventing traditional data inversion steps. This framework can be adjusted to accommodate any predictions related to subsurface conditions; hence, our second goal involves predicting the system's long-term responses within the BEL based on short-term data collection, forecasting posterior distributions from the acquired short-term data, and validating the efficacy of this approach.

Our study indicates that in practical engineering, by (1) obtaining data of material properties and (2) key responses of short-term simulation, it is possible to predict the critical responses of the system in long-term geothermal extraction, thereby maximizing the information content of any measurement data while minimizing budget constraints and computational costs.

How to cite: Zhang, L., Daniilidis, A., Dieudonné, A.-C., and Hermans, T.: Bayesian Evidential Learning Approach to Uncertainty Quantification in THM Model of Geothermal Energy Extraction in Deep Mines, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10336, https://doi.org/10.5194/egusphere-egu24-10336, 2024.

EGU24-10490 | Orals | ERE2.9

Seismic hazard related to deep geothermal operations (Part II) : iterative methodology for hazard assessment  

Julie Maury, Francesca De Santis, Mariane Peter-Borie, Emmanuelle Klein, Pascal Dominique, and Isabelle Contrucci

Ineris and BRGM published a good practices guide and recommendations for the management of seismicity induced by deep geothermal energy operations. It includes a method to assess the seismic incident hazard, defined as an event whose intensity could cause nuisances for the population, affect the local buildings and infrastructures and which could adversely impact the operating conditions and even the continuation of the project. This method has been developed based on more than 50 case studies consisting of projects representative of different types of geothermal systems where induced seismicity occurred or not. Based on an iterative approach, the method recommends hazard assessment at each key step of a geothermal project to benefit from the additional knowledge it bring. The main key steps identified are the initial assessment before frilling occur, a reevaluation just after drilling and a reevaluation before any potential stimulations. Hazard assessment is based on a decision tree approach, involving specific criteria for each project phase. The seismic incident hazard is rated with a score between 0 and 3. At the lowest level (0), no specific measures to manage induced seismicity are required. For level 1 and 2, monitoring and management methods must be developed. At level 3, the project is considered to be beyond potential induced seismicity management (it’s deviating from the plan) and operations must be suspended pending the outcome of further investigations. This method has been tailored for helping and guiding operators and French administration to consider and manage induced seismicity hazard for every deep geothermal project. 

How to cite: Maury, J., De Santis, F., Peter-Borie, M., Klein, E., Dominique, P., and Contrucci, I.: Seismic hazard related to deep geothermal operations (Part II) : iterative methodology for hazard assessment , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10490, https://doi.org/10.5194/egusphere-egu24-10490, 2024.

Besides the amount of a thermal fluid produced and its chemical composition, temperature is one of the key parameters for the utilization of hydrothermal heat. This applies in particular to geothermal fields with low temperature/low enthalpy, as too low extraction temperatures can mean the failure of a project, while higher temperatures can enable electricity generation or generally better economic efficiency. This concerns the undisturbed (natural) temperature in the reservoir as well as that of the produced fluid at the surface, which depends on the well completion, the undisturbed reservoir temperature, and the depth and contributions of hydraulically active zones. Subsequently, improved forecasts of both the undisturbed temperature and the production temperature with a valid estimate of their uncertainty are required to provide a reliable basis for field development and risk assessment.

In the national projects Geothermal-Alliance Bavaria and KompakT, we studied the temperatures in the North Alpine Foreland Basin in Bavaria, Germany. The carbonate rocks form one of Europe’s most important reservoirs for the use of deep geothermal energy, and projects for district heating and electricity generation have been realized here for more than 30 years.

We developed a good practice workflow for the correction of low-quality bottom hole temperature (BHT) values based on a probabilistic Monte Carlo approach. Using this workflow, we corrected BHTs from over 300 hydrocarbon and geothermal wells and predicted the natural temperature field inside the study area. The resulting temperature model is based on risk scenarios and contains a range of uncertainty, the extent of which depends on the uncertainty of the correction input parameters at the individual locations.

To study the short-term and long-term thermal behavior in the reservoir and the wellbore during production conditions, in 2019, a fiber optic cable was installed below the pump into the reservoir of a geothermal production well. We used distributed temperature sensing (DTS) to observe the hydraulically active zones and to thermally derive their contribution to the available heat amount.

The knowledge gained underlines the importance of flow zone characterization and can be used to improve existing temperature models and estimate what temperatures can really be expected during extraction.

How to cite: Schölderle, F. and Zosseder, K.: The Uncertainty of Temperature Predictions and the Influence of Flow Zones on the Production Temperature in a Low Enthalpy Geothermal Field, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10641, https://doi.org/10.5194/egusphere-egu24-10641, 2024.

Geothermal projects relying on superhot rocks (SHR), such as the Japan Beyond-Brittle Project, Iceland Deep Drilling Project, and Newberry Volcano, aim to harness heat from geothermal reservoirs where water reaches a supercritical state (temperature ≥ 400 °C and pressure ≥ 22 MPa). Such projects could multiply the power output of geothermal power plants by a factor of ten, positioning them at the forefront of the energy transition. However, a major challenge hindering the widespread application of SHR is the fact that supercritical water resources are often found in regions of the crust where rocks exhibit ductile behavior, a rheological regime where the formation of large-scale fractures and cracking is hindered. However, these fractures are crucial for enabling water flow, and currently, the evolution of rock permeability and other hydraulic properties in this context remains largely unknown.

This study presents experiments conducted in TARGET, a newly designed gas-based triaxial apparatus located at EPFL, CH. Cylindrical cores of Lanhélin granite (40 x 20 mm) were deformed under an effective confining pressure of 100 MPa, temperatures ranging from 200 to 800 °C, and a strain rate of 10-6 s-1. Continuous recording of sample permeability using the pore pressure oscillation method was carried out during deformation. Moreover, post-mortem samples were retrieved and scanned at the ESRF synchrotron facility (Grenoble, FR) and the tomographs were used to reconstruct the 3D crack network. Flow in the sample was then modelled using the Avizo XLab extension and permeability was computed in the x y and z direction.

We report that Lanhélin granite transitions from being in the localized regime with the formation of a sample scale fracture to becoming ductile between 600 and 800°C. In the brittle, localized regime, sample permeability remains relatively constant throughout deformation. In the ductile regime, sample strength is halved, and beyond the initial decrease upon loading, permeability increases monotonically by more than an order of magnitude. These results suggest that sample bulk controls the sample permeability in our experiments. In localizing samples, fractures do not connect the ends of the rock core but concentrate all strain after nucleation, limiting permeability improvement through micro-cracking in the bulk. In the ductile regime, where no localization occurs, the bulk permeability of the rock continuously improves with strain. Flow modeling in post-mortem samples yielded permeability values up to seven orders of magnitude greater than in-situ measurements. This substantial difference is attributed to the effect of confining pressure on the crack network aperture. Despite this absolute difference, our modeling results confirm that flow in nominally ductile samples is controlled by bulk cracking rather than macroscopic fractures. Our study demonstrates that low-porosity rocks in the ductile regime can be more permeable than often anticipated. These results hold significant implications for the engineering of SHR reservoirs, showcasing the potential for permeability enhancement in ductile rocks.

How to cite: Meyer, G., Shahin, G., Cordonnier, B., and Violay, M.: Permeability of experimentally deformed ductile granite derived from in-situ measurements and post-mortem X-ray tomography: perspectives for superhot rock reservoirs., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10980, https://doi.org/10.5194/egusphere-egu24-10980, 2024.

EGU24-11082 | ECS | Orals | ERE2.9 | Highlight

Seismic hazard related to deep geothermal operations (Part I): identification of key criteria for hazard assessment  

Francesca De Santis, Julie Maury, Emmanuelle Klein, Mariane Peter-Borie, Isabelle Contrucci, and Pascal Dominique

Deep geothermal projects can trigger seismic events depending on geological context and operations. This seismicity is generally of low magnitude but, in some cases, larger events may occur, which could lead to geothermal project abandonment and could present risk to neighboring populations. Thus, development of deep geothermal projects requires the management of induced seismicity to control it and to avoid any surface disturbance. It is from this perspective that, in 2023, Ineris and BRGM published a guide of good practices and recommendations for operators and French administration involved in deep geothermal energy.

The guide provides recommendations for assessing geothermal-induced seismic hazard, depending on the type of geothermal system and its intrinsic and operational characteristics, at each key step of a project (i.e. from the exploration phase until the end of the project). A worldwide review of deep geothermal projects, carried out with the aim of identifying key factors triggering induced seismicity, has enabled the definition of the most relevant criteria to take into account in the hazard assessment. In this review, geothermal projects were chosen to be representative of different types of geothermal systems (e.g. deep sedimentary aquifers, volcanic and plutonic regions, deep dry crystalline basements, etc.) and operating conditions (e.g. well configuration, type of operation, etc.). Moreover, the review includes projects associated with several episodes of induced seismicity, ranging in magnitude from microseismicity (M < 2) to large seismic events (M > 5), as well as projects marked by the absence of induced seismic activity.

From the 53 projects and 77 seismic episodes analyzed in this review, we can state that not all geothermal projects are equally prone to seismic events. The occurrence and the intensity of induced seismicity are the results of interactions between several natural (intrinsic) and anthropogenic (operational) factors, often concomitant and dependent on each other. Seismic response of analyzed projects appears to be largely different depending on the type of geothermal system. Indeed, the type of geothermal system characterizes reservoir porosity, as well as heat transfer and fluid circulation modes in the reservoir. Other key factors include the presence of faults that can be critically loaded and/or connected with the basement, the use of EGS technologies, and situations where injected and produced volumes are highly unbalanced. These results allowed defining key criteria for seismic hazard assessment methodology proposed within the good practice guide.

How to cite: De Santis, F., Maury, J., Klein, E., Peter-Borie, M., Contrucci, I., and Dominique, P.: Seismic hazard related to deep geothermal operations (Part I): identification of key criteria for hazard assessment , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11082, https://doi.org/10.5194/egusphere-egu24-11082, 2024.

EGU24-11792 | ECS | Posters on site | ERE2.9

Structural characterization of hydrothermal fluid pathways in orogenic belts: Insights from the GeoTex project, Rhône Valley, Switzerland 

Timothy C. Schmid, Marco Herwegh, Alfons Berger, Sandro Truttmann, Larryn W. Diamond, Christoph Wanner, Daniela B. Van den Heuvel, Herfried Madritsch, and Tobias Diehl

Meteoric water may or may not infiltrate deeply into high-relief mountain ranges. Along its subsurface circulation path, the water heats up according to the background geothermal gradient and eventually emerges at lower elevation as thermal springs. Whether such topographically-driven circulation establishes or not depends on the host rock’s permeability and/or the hydraulic head. In terms of permeability, fault zones play an important role as they can provide preferential flow paths for fluids. This is particularly the case of active fault zones along which recurring slip counteracts clogging caused by mineral precipitation often found along non-active structures. Thus, the investigation of 4D fault and fracture geometries and their kinematics is a means to understand the locations and dynamics of geothermal systems in orogenic belts. Here, we present preliminary results from the ongoing GeoTex research project, which aims at better defining the geothermal potential of the Rhône Valley, an area of rugged topography in SW Switzerland. The Rhône Valley represents a geothermally active zone within the Alpine orogen, which is characterised by numerous thermal springs, regional-scale faults and enhanced seismic activity. It is therefore a promising setting to explore further for exploitation.

Based on structural data from fieldwork and quantitative remote sensing, we characterise fault geometries (i.e., spatial orientation, relationship of intersecting fault families as well as kinematics) in the vicinity of known thermal springs. Observable paleo-fluid pathways marked by veins and rock alteration are being considered as analogues for recent thermal water circulation. These circulation paths are linked to major Alpine structures in the underlying basement units, such as large-scale strike-slip faults or the axial planes of uplifting basement domes. Our results suggest spatial correlations between the locations of hydrothermal springs and the 3D structure of the host massifs. Specifically, basement–cover contacts exert geometric and lithologic control at some sites, whereas locally dilatant domains along strike-slip faults as well as intersections of fault families focus outflow at other sites. Through the above approach in combination with seismological data, we have derived conceptual models for fluid flow, which may help to predict the locations of blind active geothermal systems elsewhere in the Rhône Valley.

How to cite: Schmid, T. C., Herwegh, M., Berger, A., Truttmann, S., Diamond, L. W., Wanner, C., Van den Heuvel, D. B., Madritsch, H., and Diehl, T.: Structural characterization of hydrothermal fluid pathways in orogenic belts: Insights from the GeoTex project, Rhône Valley, Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11792, https://doi.org/10.5194/egusphere-egu24-11792, 2024.

The carbonate Upper Jurassic aquifer (UJA) in the South German Molasse Basin (SGMB) is the most important exploration horizon for geothermal energy supply in Bavaria. The UJA shows a complex hydrogeology caused by a heterogeneous geology with karstic features and deep fault zones.

The great interest in the Upper Jurassic aquifer for geothermal energy supply led to an increasing construction of geothermal power plants in the greater Munich area. Today, there are 18 geothermal power plants in this area used for district heating and electricity generation.

To guarantee a long and sustainable use of the geothermal resource, understanding the dynamics within the reservoir is important. Tracer tests are a key tool for investigating groundwater flow paths, detecting potential thermal breakthroughs, and minimizing negative interactions between geothermal power plants.

In recent years, several tracer tests have been conducted, and the growing number of projects will lead to even more tracer testing in the coming years. Future tracer tests need to be carefully designed, as there is, up to now, only a limited number of traditional tracer substances available for use in a deep geothermal setting under high temperatures and pressures. Therefore, we developed tracer management for the UJA, including guidelines for different tracer tests, the suitability of different tracers for usage in a geothermal setting, and recommendations for individual locations.

How to cite: Winter, T. and Zosseder, K.: Developing tracer management for long and sustainable use of the Upper Jurassic geothermal reservoir in South Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17350, https://doi.org/10.5194/egusphere-egu24-17350, 2024.

EGU24-17666 | Posters on site | ERE2.9

Mechanical stiffness and permeability of a reservoir-scale rough fracture during closure 

Jean Schmittbuhl, Qinglin Deng, Mauro Cacace, and Guido Blöcher

Natural or artificial fluid flow in deep fractured reservoirs, such as Enhanced Geothermal Systems (EGS), is primarily controlled by open fractures and faults, and is considered a key element for hydraulic performance. Flow along these fractures is strongly affected by channeling between fracture asperities and by deposits sealing the open fracture space due to mineral precipitation. Fracture asperities and fracture sealing also impact the mechanical behavior of fractures, especially their mechanical stiffness. Here, we study both the permeability and the stiffness of a rough fracture at the field scale during its closure.We base our approach on a well established self-affine geometrical model for fracture roughness. We develop a finite element model based on the MOOSE/GOLEM framework and conduct numerical flow experiments in a 256 × 256 × 256 m^3 granite reservoir hosting a single, partially sealed fracture under variable normal loading conditions. Navier-Stokes flow is solved in the embedded 3-dimensional rough aperture, and Darcy flow is solved in the surrounding poroelastic matrix. We study the evolution of the mechanical stiffness and fluid permeability of the fracture-rock system during fracture closure by considering the asperity yield and the depositing of fracture-filling material in the open space of the rough fracture. The evolution of the fault volume, fracture normal stiffness and permeability are monitored until fluid percolation thresholds are exceeded in two orthogonal directions of the imposed pressure gradient. Finally, we propose a physically based law for the stiffness and permeability evolution as a function of the fault volume. It is demonstrated that during closure, stiffness increases exponentially as the fault volume decreases. A strong anisotropy of the fracture permeability is also evidenced when reaching percolation thresholds.

How to cite: Schmittbuhl, J., Deng, Q., Cacace, M., and Blöcher, G.: Mechanical stiffness and permeability of a reservoir-scale rough fracture during closure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17666, https://doi.org/10.5194/egusphere-egu24-17666, 2024.

EGU24-18451 | ECS | Posters on site | ERE2.9

Large-scale reservoir modeling of the Vendenheim geothermal site (France) 

Javier Abreu Torres, Gergo Hutka, Mauro Cacace, Guido Blöcher, Vincent Magnenet, and Jean Schmittbuhl

During the Vendenheim deep geothermal project (Strasbourg Eurometropole, France), large induced seismic events led to the arrest of the project. Two important features of the induced seismicity were unexpected : the large distance to the wells of a cluster of seismic events (4-5km) and the occurrence of the largest event Mlv3.9 at the bottom of the wells, six months after shut-in. To better understand the mechanisms of seismicity, we develop within the framework of the DT-GEO project (Horizon Europe) a large-scale model (8kmx8kmx8km) of the area. We aim at performing in-silico experimentation to reproduce the geophysical responses of the geothermal reservoir with different geological geometries, different geomechanical properties and constrained with a variety of crustal stress conditions and variety of the external forcing representing the anthropogenic control. The model is based on the MOOSE/GOLEM framework (finite element approach) and integrate the public regional geological model GEORG that includes major lithologies and large-scale faults of the area. We will present the preliminary of coarse-grained simulations of the natural fluid circulation and fluid injections.

How to cite: Abreu Torres, J., Hutka, G., Cacace, M., Blöcher, G., Magnenet, V., and Schmittbuhl, J.: Large-scale reservoir modeling of the Vendenheim geothermal site (France), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18451, https://doi.org/10.5194/egusphere-egu24-18451, 2024.

EGU24-18565 | ECS | Posters on site | ERE2.9

Flow focusing associated with doublet operation 

Fahim Mumand and Jörg Renner

Heat and cold storage in the subsurface as well as geothermal energy provision intrinsically involve cyclic pumping operations, often in fields of several boreholes. We investigated the pressure and flow-rate fields resulting from the simultaneous periodic operation of two boreholes. The interference in pressure experienced by further (monitoring) boreholes can be assessed by an analytical solution when assuming radial flow from and to the pumping wells. This solution is derived through superposition, relying on the known solution for periodic pumping in a single well. The pressure gradient field, indicative of flow direction, is distorted from radial form, implying dominant flow and consequently heat advection between the two boreholes. We compared the analytical results to observations from field tests conducted in four boreholes located close to the northwestern banks of an artificial freshwater reservoir, the Kemnader See, at the southern city-limits of Bochum, Germany. In the light of the derived solutions, the field observations allow us to assess the role of inhomogeneity and fracture flow for the flow focusing between the pumping wells. Solving and investigating the hydraulic problem constitutes the necessary first step towards devising schemes for the optimization of cold and heat storage or geothermal energy provision by varying the period and phase of pumping coeval operations in several boreholes.

How to cite: Mumand, F. and Renner, J.: Flow focusing associated with doublet operation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18565, https://doi.org/10.5194/egusphere-egu24-18565, 2024.

EGU24-18812 | ECS | Orals | ERE2.9

Deep U-tube heat exchanger breakthrough: combining laser and cryogenics gas for geothermal energy exploitation – a perspective of laser-rock interactions 

Pawel Slupski, Enrico Zampieri, Eloisa Di Sipio, Adele Manzella, Riccardo Pasquali, Luc Pockele, Arno Romanowski, Raffaele Sassi, Olaf Steinmeier, and Antonio Galgaro

The technology envisioned in the DeepU project (Deep U-tube heat exchanger) is expected to revolutionize the geothermal energy sector, increasing the accessibility of deep geothermal resources for low-carbon heating and power generation. The ultimate project goal is to create a deep (>4 km) closed-loop connection in the shape of a U-tube exchanger by developing a fast and effective laser drilling technology. The project comprises the development of a novel drilling technique and its application via geothermal modeling at selected sites. A prototype of a drill-head has been realized, combining the laser system with drill strings, sustaining the coupled action of laser and cryogenic gas. The fine particles of drilled rocks are ejected to the surface in the gas stream via the borehole annulus. This contribution focuses on the project’s activities related to the laser-rock interactions studied in the experimental laser drilling tests based on previous works (Seo et al., 2022; Li et al., 2022a, 2022b). Three types of lithologies were selected for initial laboratory tests: granite, sandstone, and limestone (50 x 35 x 15 cm). Constant rates of penetration (ROP) upwards of 20 m/h have been achieved in all lithologies with borehole diameter reaching 18 cm. The petro-thermo-mechanical phenomena occurring during laser drilling, such as spallation, melting, and evaporation, were recognized and described. The drilling process was investigated by thermocamera imaging providing information about the most effective process induced by heating the rocks, up to 700°C. The laser working parameters and experimental setup were optimized regarding observed phenomena. In the next step, sections of boreholes were cut out and examined. The microscopic observations on the thermal unaffected and affected rocks’ thin sections have been performed with the use of polarized optical microscopy and scanning electron microscopy revealing micro-fracturing patterns of the rock induced on rock samples by the heating processes. The change of physic-mechanical properties of rocks was investigated and acknowledged in geothermal models. This innovative and comprehensive study revealed macro- and micro-scale phenomena occurring during laser drilling, contributing to the successful development of this new drilling method and subsequently its application for exploitation of geothermal energy from depths below 4 km.

This research is funded by the European Union (G.A. 101046937). However, the views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or EISMEA. Neither the European Union nor the granting authority can be held responsible for them.

References

Li, G., Shi, D., Hu, S., Ma, C., He, D., and Yao, K., 2022a, Research on the mechanism of laser drilling alumina ceramics in shallow water: The International Journal of Advanced Manufacturing Technology, v. 118, p. 3631–3639, doi:10.1007/s00170-021-08190-0.

Li, Q., Zhai, Y., Huang, Z., Chen, K., Zhang, W., and Liang, Y., 2022b, Research on crack cracking mechanism and damage evaluation method of granite under laser action: Optics Communications, v. 506, p. 127556, doi:10.1016/j.optcom.2021.127556.

Seo, Y., Lee, D., and Pyo, S., 2022, The interaction of high-power fiber laser irradiation with intrusive rocks: Scientific Reports, v. 12, p. 680, doi:10.1038/s41598-021-04575-z.

How to cite: Slupski, P., Zampieri, E., Di Sipio, E., Manzella, A., Pasquali, R., Pockele, L., Romanowski, A., Sassi, R., Steinmeier, O., and Galgaro, A.: Deep U-tube heat exchanger breakthrough: combining laser and cryogenics gas for geothermal energy exploitation – a perspective of laser-rock interactions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18812, https://doi.org/10.5194/egusphere-egu24-18812, 2024.

EGU24-20414 | Orals | ERE2.9 | Highlight

A newly installed research infrastructure for geothermal energy in a subsurface sedimentary reservoir for direct-use heating: the TU Delft campus geothermal project 

Hemmo Abels, Auke Barnhoorn, Alexandros Daniilidis, David Bruhn, Guy Drijkoningen, Kaylee Elliott, Beer van Esser, Susanne Laumann, Piet Van Paassen, Liliana Vargas Meleza, Andrea Vondrak, Denis Voskov, and Phil Vardon

A geothermal doublet has been installed in a sedimentary reservoir for direct-use heating on the TU Delft campus, targeted to supply around 25 MW of thermal energy at peak conditions. This contribution presents the implementation and initial data collection from the doublet, including an initial evaluation of the logging and coring campaign. Nearly half of Netherlands natural gas consumption is allocated to heating, and the on-campus CO2 emissions from heating exceed 50%. The doublet has been designed with two primary aims of research and commercial heat supply, with the wells being completed in December 2023. The project will be operated by a commercial entity, and built into a larger thermal energy system including a high temperature underground storage system, with the first energy production planned in 2025. The research questions relate to field-scale geothermal operations, e.g. how reliable is the long-term energy production?, how do materials perform in the long-term? and how can geothermal projects be best monitored? The research programme involves the installation of a wide range of instruments alongside an extensive logging and coring program and monitoring network. The doublet has been cored, with substantial continuous samples from the heterogenous reservoir, alongside a large suite of open hole well logs in the reservoir and through casing logs in overlying geological units. A fiber-optic cable will monitor distributed pressure throughout the producer reservoir section, at approximately 2300m depth, which will be installed during commissioning. A local seismic monitoring network has been installed in the surrounding area with the aim of monitoring very low-magnitude natural or induced seismicity. The project is a key national research infrastructure and is being incorporated into the European EPOS (European Plate Observing System, https://www.epos-eu.org/), such that accessibility and data availability will be as wide as possible. All observations will be included in a digital-twin framework that will allow to make better decisions in future geothermal projects.

How to cite: Abels, H., Barnhoorn, A., Daniilidis, A., Bruhn, D., Drijkoningen, G., Elliott, K., van Esser, B., Laumann, S., Van Paassen, P., Vargas Meleza, L., Vondrak, A., Voskov, D., and Vardon, P.: A newly installed research infrastructure for geothermal energy in a subsurface sedimentary reservoir for direct-use heating: the TU Delft campus geothermal project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20414, https://doi.org/10.5194/egusphere-egu24-20414, 2024.

EGU24-20667 | ECS | Orals | ERE2.9

Generation of High Resolution Seismic Catalog Associated With the Production Phase 2021 - 2022 at the Balmatt Geothermal Site 

Rachit Gautam, Jannes L. Kinscher, Jean Schmittbuhl, Matsen Broothaers, and Ben Laenen

The Balmatt geothermal doublet, developed and managed by VITO (Flemisch Institute of Technological Research), targets the fractured Lower Carboniferous Limestone reservoir in the Campine Basin at the depth of 3000 m to 4000 m. The development of the project started in 2015 and the operation began in 2018. The geothermal plant consists of two active wells, one injection well and one production well. The geothermal production had to be suspended after the occurrence of a stronger ML 2.2 event on the 23rd of June 2019 which triggered a red alert status on the local traffic light system (TLS). Production was then resumed in April 2021, following an extension of the seismic monitoring network and an update of the TLS. Activities were suspended again in November 2022 after another strong ML 2.1 event was induced. Thanks to the network extension, current investigations aim at understanding in detail the main structural features (active faults) and hydromechanical processes involved in the generation of such larger events which will contribute to improving seismic forecast possibilities for future monitoring operations. Here we present insights into ongoing data processing to create a high resolution unbiased (complete) seismic catalog providing the basis for future interpretation of the spatio-temporal and energetic behavior of seismicity towards different production settings. Our current work focuses in particular on the development of an automatic detection routine based on continuous data of the deep borehole sensor (installed at the depth of 2052 m) by combining a machine learning based automatic events detection algorithm and template matching method. The events detection in the continuous data is complicated by the periodic malfunctioning of the sensor and the presence of aseismic noise which leads to the large number of false events detection. To address this issue and to minimize the number of false detections, we employ frequency and amplitude analysis of the seismic data. Secondly we analyze source attributes of the detected events which involve source mechanism inversion and source parameter determination as well as clustering analysis and constraining source location for noisy small magnitude events. Further more the comparison between the production data (injection pressure, temperature, volume etc.) with the results from the seismic analysis will provide us with better constrain on the hydromechanical characteristics of the reservoir and the relation between the geothermal operations and seismicity at Balmatt geothermal site. 

How to cite: Gautam, R., Kinscher, J. L., Schmittbuhl, J., Broothaers, M., and Laenen, B.: Generation of High Resolution Seismic Catalog Associated With the Production Phase 2021 - 2022 at the Balmatt Geothermal Site, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20667, https://doi.org/10.5194/egusphere-egu24-20667, 2024.

EGU24-20785 | Orals | ERE2.9

The power generation potential of enhanced geothermal systems in ductile crust at >15 km depth 

Samuel Scott, Alina Yapparova, Philipp Weis, and Matthew Houde

This study explores the power generation potential of enhanced geothermal systems (EGS) at depths of >15 km, where continental crust typically exhibits ductile behavior at temperatures above 400 °C. We employed a numerical model to evaluate the response of such deep crustal rock to fluid injection-induced pressurization and cooling. Our simulations indicate that circulating 80 kg/s of water through rock initially at 425 °C could yield ~100-120 MWth (approximately 20 MWe) for two decades. Even after a century of fluid circulation, fluid temperatures at the production wells exceed 250 °C and thermal energy output exceeds 40 MWth. However, achieving effective permeability in the stimulated volume is crucial to developing an exploitable resource; our model suggests that bulk permeability values between ~10-15 and 10-14 m2 in a rock volume of 0.1 km3 are optimal. This range balances the need to avoid excessive injection pressures and the risk of rapid thermal depletion. As the reservoir cools, the transition from ductile to brittle behavior in rock is assumed, reducing fluid pressures but increasing the risk of fluid pathway short-circuiting, a common challenge in EGS operations. Our theoretical investigation underscores the importance of geological (e.g., rock temperature and permeability) and operational (e.g., injection rate) factors in harnessing the energy potential of the ductile crust. However, practical implementation hinges on revolutionary advancements in deep drilling technology and a better understanding of rock behavior under high temperature and pressure conditions.

How to cite: Scott, S., Yapparova, A., Weis, P., and Houde, M.: The power generation potential of enhanced geothermal systems in ductile crust at >15 km depth, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20785, https://doi.org/10.5194/egusphere-egu24-20785, 2024.

EGU24-21025 | Orals | ERE2.9

Quantifying the 4D Seismic Density Evolution Caused by Geothermal Injection 

Zhiwei Wang, Olivier Lengliné, and Jean Schmittbuhl

The injection of geothermal water into subsurface rock formations often induces a cascade of seismic events. However, a comprehensive understanding of the resulting temporal and spatial seismic density evolution remains elusive. In this study, we meticulously analyze both spatial and temporal earthquake probability density distributions. Leveraging data from multiple injection sequences obtained from the EPOS TCS-AH through the EPISODES Platform, our objective is to elucidate the spatiotemporal evolution of seismic activity across distinct phases of water injection. We extend our focus to quantify seismicity during the post-injection phase and assess whether the largest magnitude event in each sequence aligns with the derived distribution. This time, our primary emphasis is on conducting the above-mentioned analysis on the 09/1993 Soultz-sous-Fôret sequence. Our research is supported by Horizon Europe under grant agreement No. 101058129 as part of the DT-Geo Project.

Our findings reveal a distinctive characteristic of seismic spatial density, marked by a sudden decay at extended distances. Remarkably, there is no significant divergence in spatial density decay observed before and after the cessation of injection. Furthermore, we observe that the occurrence of the maximum magnitude event coincides with the peak of the probability spatial density. Shifting to temporal density, we identify a close correlation with the increase in injection volume, displaying a skewed normal distribution. Notably, the maximum magnitude event aligns with the peak of the probability temporal density.

In essence, our research substantively contributes to a quantitative comprehension of the dynamic features governing the temporal and spatial evolution of seismic density during intensified water injection scenarios.

How to cite: Wang, Z., Lengliné, O., and Schmittbuhl, J.: Quantifying the 4D Seismic Density Evolution Caused by Geothermal Injection, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21025, https://doi.org/10.5194/egusphere-egu24-21025, 2024.

The storage of surplus power generated by wind turbines or solar panels under favourable weather conditions is of significant importance for the successful transition of current energy systems. Surplus power can be used for hydrogen production or for charging batteries. However, there is also an option to store surplus power as mechanical energy due to the injection of water into the deep underground.

Basic investigations for the storage of mechanical energy were performed at the geothermal research well “Horstberg” in Germany. Here a large and highly conductive artificial fracture was created in the Buntsandstone formation at approximately 3800 m depth. For the hydraulic stimulation 20.000 m3 of fresh water were injected at a pressure of about 300 bar. In succeeding production tests, the water was produced back at a pressure level of about 200 bar and a significant portion of the energy used for injection would have been retrievable. Further injection and production tests, originally designed for cyclic heat extraction, showed that approximately half of the electric energy necessary for injection could have been recovered while producing. Obviously, a large portion of the hydraulic pump energy is stored in the underground as mechanical energy due to ballooning of the fracture and due to elastic compression of water and rock surrounding the fracture.

The efficiency of energy storage can be improved significantly by implementing a horizontal well design with multiple fractures. This is shown based on model calculations. If water is injected in parallel artificial fractures the static pressure level between the fractures increases, water losses into the far field decrease and the back-production is improved. Furthermore, overpressure reservoirs and low permeable rock are favourable. Thereby the injected water remains in the closed surrounding of the fractures and the complete artesian back production at high pressure is ensured. Overpressure formations seem to be widespread in the deep underground of sedimentary basins as in the North German Basin.

Mechanical energy storage in the deep underground should be combined with geothermal heat extraction. At the test site Horstberg thermal water at a temperature of more than 100°C was produced in cyclic tests. Numeric modelling results suggest that a thermal power of appr. 1 MW can be extracted by cyclic production in the long term via the large fracture in Horstberg.

For the realisation of this storage concept several challenges have to be met. Besides the creation of good underground conditions, the handling of the produced saline water and its reinjection without scaling or corrosion are serious issues. On the other hand the storage of surplus power as mechanical energy in the underground and its retransformation to power can be more efficient than the conversion into hydrogen and less expensive than battery storage. The reuse of abundant deep wells for energy storage could be a cost-efficient starting point for this concept.

How to cite: Tischner, T. and Jung, R.: Storage of mechanical energy and heat extraction via artificial fractures in low permeable rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21854, https://doi.org/10.5194/egusphere-egu24-21854, 2024.

EGU24-10031 | Posters on site | ERE2.10

Water-driven geothermal heat extraction with simultaneous CO2 injection: overview of concepts, benefits and challenges 

Annick Loschetter, Christophe Kervévan, Rowena Stead, and Thomas Le Guénan

Geothermal energy production and CCS (Carbon Capture and Storage) represent promising technological solutions to help mitigate climate change and aid the current global energy crisis. In recent years, the number of concepts that propose to combine and mutualize these technologies has risen dramatically. While a number of concepts (notably CPG and CO2-EGS) use supercritical CO2 as the heat vector, another promising route for hybridization is to inject dissolved CO2 in the geothermal brine. This is the focus of our current work. An extensive literature review was carried out of the concepts, complemented by interviews of some of the developers.

A few concepts are still theoretical (only described in the literature), but most technological ones are on the way to pilot/demonstration projects at progressively increasing scale. The main projects and their associated sites are:

  • CO2-DISSOLVED technology, with potential sites identified in the Paris basin (France);
  • AAT-G / Cleag technology, with a site in Croatia;
  • Related projects CarbFix, GECO and SUCCEED, with sites in Hellisheidi (Iceland), Nesjavellir (Iceland), Bochum (Germany), Kızıldere (Turkey), Castelnuovo in Italy (as case study due to permitting issues);
  • Reinjection of CO2 from geothermal brines at Ngatamariki and Te Huka sites in New Zealand.

Despite similarities, these solutions are differentiated by their purpose:

  • either to store CO2 from an external industrial emitter (notably for the CO2-Dissolved concept), thus bringing a contribution to CCS,
  • or to reinject CO2 emitted by CO2-rich brine during geothermal exploitation, thus bringing geothermal to near-zero emissions.

Because of the CO2 solubility limit in brine, the performance of heat extraction is generally higher than that of CO2 storage. For instance the CO2-DISSOLVED technology is particularly well-suited to small CO2 industrial emitters (ca. <150,000 t CO2/year). Unlike concepts using supercritical CO2, those using dissolved CO2 can be deployed at much lower depths (no need to exceed the supercritical point). The concepts still need a tight caprock, but the high solubility trapping represents a lower risk of leakage. The geothermal system behaves mainly as a water-driven system, but the adjunction of dissolved CO2 can in some cases increase thermo-hydrological performance (pH decrease might avoid clogging and/or open porosity in carbonate reservoirs).

A number of challenges still need to be addressed, including complexity of regulations and validation of some technical aspects. Besides, considering the variety of underground configurations, there is no turnkey solution, which might hamper the economics of such small-scale projects.

Acknowledgements: This work is in part taken from a study published in the report ‘IEAGHG, “Prospective integration of Geothermal Energy with Carbon Capture and Storage (CCS)”, 2023-02, August 2023’. We are grateful to IEAGHG, especially to Nicola Clarke, for proposing and funding this topic and for interesting scientific discussions and debates as part of this work.

How to cite: Loschetter, A., Kervévan, C., Stead, R., and Le Guénan, T.: Water-driven geothermal heat extraction with simultaneous CO2 injection: overview of concepts, benefits and challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10031, https://doi.org/10.5194/egusphere-egu24-10031, 2024.

EGU24-10206 | Posters on site | ERE2.10 | Highlight

CPG Subsea Power Plant – When solutions come together 

Sebastian Köhlert

As oil and gas production will most likely go down in the next decades and CPG is waiting for deployement in a wide scale, future applications should be investigated on a wide scale.

CPG (CO2 plume geothermal system) is a great way to improve efficiency and feasibility of geothermal power plants. Subsea Compressors made by MAN Energy Solutions are used to improve efficiency in oil and gas production. At the first glance these are two technologies which have no link.

But putting both things together results in a new approach to produce sustainable energy for offshore use. A turbine necessary to run a CPG plant is a technology not very different to a compressor. Feasibility was positively checked by the experts of MAN Energy Solutions. Problems like increased necessary steam temperature in high pressure environments - like the deep sea - in classical geothermal power production are no object with CPG.

Works from Martin O. Saar et al. showed the great potential of CPG onshore. A use offshore or even subsea is closely linked to potential apllications and the comparison with other technologies to produce sustainable energy for offshore use.

Possible future consumers like fuel production (H2, methanol, ammonium), subsea data centers, CO2 storage or desalination plants can benefit from a sustainable and reliable local power source.

The right LCOE (Levelized Cost of Electricity) is the final paramter to be met. Investigations showed that with the right side conditions a competitive LCOE compared to other offshore baseload capable power plants like OTEC (ocean thermal energy conversion), or wave, tidal, wind and solar with energy storage is possible.

How to cite: Köhlert, S.: CPG Subsea Power Plant – When solutions come together, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10206, https://doi.org/10.5194/egusphere-egu24-10206, 2024.

EGU24-10470 | Posters on site | ERE2.10 | Highlight

Overview of how subsurface carbon dioxide promotes geothermal energy extraction 

Martin O. Saar

The properties of carbon dioxide (CO2) under deep geologic conditions make it an excellent subsurface working fluid in geothermal systems, including CO2-Plume Geothermal (CPG) systems, Enhanced Geothermal Systems (EGS), and deep closed-loop Advanced Geothermal Systems (AGS). Supercritical CO2’s low viscosity, high density, and high thermal expansion coefficient render CO2 a highly efficient energy transfer, extraction, and storage fluid. These properties typically overcompensate the lower specific heat capacity of CO2, compared to brine, which is the conventional working fluid underground. Furthermore, CO2 can also reduce fluid-mineral reactions, such as mineral precipitation, which often clog reservoirs, wells, and equipment. Applying geothermal energy extraction to CO2 Capture and Sequestration (CCS) in deeper reservoirs results in true CO2 Capture Utilization and Sequestration (CCUS), enabling these projects to ultimately sequester all initially injected CO2 underground at reduced cost. In this presentation, I give an overview of how CO2 can be used to efficiently produce geothermal energy, store surface-generated energy underground, and/or support CCS operations to promote energy security while combating climate change.

How to cite: Saar, M. O.: Overview of how subsurface carbon dioxide promotes geothermal energy extraction, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10470, https://doi.org/10.5194/egusphere-egu24-10470, 2024.

EGU24-11958 | ECS | Posters on site | ERE2.10

CO2-Plume Geothermal (CPG) in Austria? Tackling the CCS dilemma 

Jakob Kulich, Tsubasa Onishi, Martin O. Saar, and Holger Ott

Austria is committed to becoming climate net-neutral by 2040, no later than 2050. Reducing the country’s hard-to-abate Carbon Dioxide (CO2) emissions will require substantial deployments of CO2 Capture Utilization and Sequestration (CCUS) to reach this challenging goal. Due to legal regulation and missing public acceptance across Europe, CO2 sequestration sites for CCUS hubs are typically being developed offshore. This is especially challenging for inland countries, such as Austria, where domestic CO2 sequestration is currently not in development and export of CO2 can only take off once CO2 transport infrastructure is completed. At the same time, geothermal energy production is seen as a key technology to provide green base-load energy to decarbonize the heating sector in cities with huge district heating networks. Utilizing CO2 as the subsurface energy extraction working fluid in future geothermal projects, called CO2-Plume Geothermal (CPG), can contribute to both storing hard-to-abate CO2 emissions until proper transport infrastructures across Europe have been developed and complementing the development of geothermal energy production. In this work, we assess the Austrian potential for using CO2 as the geothermal working fluid in depleted hydrocarbon fields. We screened 59 hydrocarbon reservoirs in Austria to assess their CCS and CPG suitability. Furthermore, we distinguish between hydrocarbon fields, suitable for heat and/or electricity production, and compute the levelized cost of energy (LCOE) production as well as the potential net energy produced by CPG. While Austria’s CO2 sequestration capacities in depleted hydrocarbon reservoirs are small, compared to saline formations in offshore Europe, developing national onshore CO2 storage sites can bridge crucial periods until the CO2 can be shipped offshore, promoting the country’s climate goals. We believe that adding CPG to CCS, resulting in CCUS, increases the acceptance of CCS in general and in particular in onshore countries. Additionally, cooling the CO2 due to energy extraction, i.e. reducing the reservoir temperature, increases the reservoir’s CO2 sequestration/storage capacity and is expected to decrease CO2 injection risks by controlling/reducing the pore-fluid pressure in the CCS/CPG reservoir.

How to cite: Kulich, J., Onishi, T., Saar, M. O., and Ott, H.: CO2-Plume Geothermal (CPG) in Austria? Tackling the CCS dilemma, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11958, https://doi.org/10.5194/egusphere-egu24-11958, 2024.

Subsurface reservoirs play an important role in decarbonizing the energy sector, be it through geothermal energy production or carbon capture and storage (CCS). In recent years, there has been an increasing interest in CO2-Plume Geothermal (CPG), which combines CCS with geothermal, using CO2 instead of water as a subsurface heat and pressure energy carrier. CO2 as a subsurface working fluid is more efficient as it has a higher mobility (inverse kinematic viscosity) and its large thermal expansion coefficient results in a thermosiphon effect that reduces the pumping power required. CO2 can also be directly utilized in a turbine for power generation. Furthermore, since CPG systems are added to full-scale CO2 Capture and Sequestration operations, all of the initially injected CO2 is ultimately stored. CPG therefore constitutes both CO2 Capture Utilization as well as Storage (i.e. CCUS).

In recent years, CPG has experienced increasing interest from academia and industry. Several in-depth studies have assessed the impact of various parameters such as the geothermal gradient, wellbore diameter or reservoir permeability on the CPG performance. However, these studies have not evaluated the potentially significant impact of the varying ambient conditions on the CPG performance profile. The potential effect of the air temperature on the CPG performance has only been discussed in a paper by Adams and Kuehn (2012) and in a more recent work by van Brummen et al. (2022), but without considering the the off-design behaviour of the main components, such as the turbine or compressor. This contribution assesses and discusses how the CPG performance profile might vary across several geographical settings and how the design point of the CPG components affect their achievable net power outpt. Therefore, valuable insights regarding the most attractive settings for future CPG systems can be drawn.

How to cite: Schifflechner, C. and Spliethoff, H.: The impact of the ambient conditions and component’s part-load behaviour on the actual annual power output of CO2-Plume Geothermal (CPG) systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12517, https://doi.org/10.5194/egusphere-egu24-12517, 2024.

EGU24-12872 | ECS | Posters on site | ERE2.10

Simulation of CO2 Injection in Mature Oil Fields: Implications for Geothermal Energy Generation 

Serhat Kucuk, Maren Brehme, Rouhi Farajzadeh, William Rossen, and Martin O. Saar

The urgent need to combat climate change underscores the importance of reducing anthropogenic CO2 levels in the atmosphere through geological sequestration. While Carbon Capture and Storage(CCS) has been applied in various settings and has demonstrated its potential over the recent decades, economic challenges associated with CCS continue to be a significant barrier to its extensive large-scale implementation. This abstract discusses a promising solution: using CO2 as a geothermal working fluid to extract heat from deep, naturally porous, and permeable geologic formations, a concept known as CO2 Plume Geothermal (CPG). Oil fields in particular are attractive candidates for the deployment of CPG due to the presence of existing well infrastructure, extensive reservoir and production data, and an effective caprock. This innovative approach not only enables enhanced oil recovery through CO2-EOR, at an initial stage, and sustainable power generation but also ensures permanent carbon sequestration. Consequently, CPG in oil fields can serve as a catalyzer to deploying large-scale CCS projects, leveraging multiple co-benefits such as energy offset, decarbonization, carbon market development, and extended operational field life.

Through a combination of advanced non-isothermal and compositional numerical reservoir models, we comprehensively examine the geotechnical feasibility of deploying CPG at oil fields. The primary objectives of this study include evaluating the geothermal energy extraction efficiency, assessing the economic and environmental co-benefits, and addressing associated performance uncertainties. Building on crucial insights from existing CO2-EOR studies, we consider factors such as the mobility differences between injected and displaced fluids, interactions between CO2, oil, reservoir brine, and rock, and flow channeling through high-permeability pathways created by the heterogeneous nature of geological reservoirs. Furthermore, we delve into the thermal and compositional variations within the reservoir induced by water flooding operations during the secondary oil recovery stage, analyzing their effects on CPG performance in comparison to unperturbed saline aquifers. Integrating geothermal energy production, enhanced oil recovery, and permanent carbon sequestration, CPG in oil reservoirs can advance the integration of renewable energy and greenhouse gas management in the global effort to combat climate change.

How to cite: Kucuk, S., Brehme, M., Farajzadeh, R., Rossen, W., and Saar, M. O.: Simulation of CO2 Injection in Mature Oil Fields: Implications for Geothermal Energy Generation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12872, https://doi.org/10.5194/egusphere-egu24-12872, 2024.

EGU24-16553 | Posters on site | ERE2.10 | Highlight

De-risking CO2-Plume Geothermal (CPG) for commercial field deployment 

Adriaan Jasper de Reus, Tsubasa Onishi, Maren Brehme, Federico Games, Kevin P. Hau, Mahmoud Hefny, Serhat Kucuk, Xiang-Zhao Kong, Daniel Pokras, Nicolas Rangel Jurado, and Martin O. Saar

CO2-Plume Geothermal (CPG) is a technology that employs the benefit of CO2 as a geothermal working fluid to turn CCS into CCUS (Carbon Capture, Utilization and Storage), both by producing more power compared to conventional geothermal systems (Randolph and Saar, 2011), as well as improving the performance of the base CO2 storage project. Following a decade of research, a CPG consortium has started in March 2023 to pave the way for de-risking this emerging technology to a Technology Readiness Level (TRL) of 7. This industry-academic initiative unlocks a larger joint portfolio of opportunities, financing options and domain knowledge, thereby enabling a systematic and standardized approach to evaluating candidate CPG field demonstration sites and concepts. A workflow is presented to define several potential field demonstration concepts, leveraging site-specific risk registers, opportunity framing sessions, competitive scoping and multi-scenario modelling. Using a trade-off table, the highest value field demonstration project can be selected for execution in the subsequent phase of the CPG consortium.

 

 

How to cite: de Reus, A. J., Onishi, T., Brehme, M., Games, F., Hau, K. P., Hefny, M., Kucuk, S., Kong, X.-Z., Pokras, D., Rangel Jurado, N., and Saar, M. O.: De-risking CO2-Plume Geothermal (CPG) for commercial field deployment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16553, https://doi.org/10.5194/egusphere-egu24-16553, 2024.

EGU24-19014 | ECS | Posters on site | ERE2.10

Techno-Economic Optimization of a CO2-based Advanced Geothermal System (AGS) 

Daniel Pokras, Mahmoud Hefny, Po-wei Huang, and Martin O. Saar

Advanced Geothermal Systems (AGS) are power systems that harness energy by circulating a working fluid through a closed-loop circuit, extracting thermal energy from deep geologic reservoirs via conductive heat transfer across an impermeable wellbore wall. AGS benefit from using carbon dioxide (CO2) as the working fluid within the wellbores, at least for electricity generation and possibly also for direct heat usage. Here, we investigate a range of configurations for combined electricity and heat production. These designs aim to enhance flexibility and efficiency in AGS while reducing system costs. Central to this research is formulating an optimal AGS pilot plant design, complemented by a comprehensive techno-economic feasibility study. Compared to the design benchmarks of previous work on AGS for electricity generation only, this optimization yields an improvement in the Specific Capital Cost (SpCC) by approximately 215%. Furthermore, by incorporating heat co-generation with electricity, the SpCC is considerably further reduced. 

How to cite: Pokras, D., Hefny, M., Huang, P., and Saar, M. O.: Techno-Economic Optimization of a CO2-based Advanced Geothermal System (AGS), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19014, https://doi.org/10.5194/egusphere-egu24-19014, 2024.

EGU24-19289 | ECS | Posters on site | ERE2.10

Integrated reservoir and production system modeling of geothermal energy extraction at the Aquistore CCS site in Canada 

Kevin P. Hau, Maren Brehme, Alireza Rangriz-Shokri, Reza Malakooti, Erik Nickel, Rick J. Chalaturnyk, and Martin O. Saar

Mitigating the global climate crisis is the greatest challenge facing humanity this
century. The transition of current energy systems towards carbon-neutral energy
is inevitable. Renewable energy sources, particularly those that are both baseload-
and dispatch-capable, such as geothermal energy, are essential to replace current
energy systems that emit large amounts of CO2. In addition, permanent isolation
of CO2 from the atmosphere, using carbon capture and sequestration (CCS), is
indispensable to limit global warming to 1.5°C.
To enable the full potential of geothermal energy extraction and of CCS, their
efficiencies need to be improved. One possibility is to integrate both technologies.
Using CO2 as the geothermal energy extraction fluid approximately doubles energy
generation rates, compared to conventional, brine-based geothermal systems under
our base-case conditions. Such CO2 Plume Geothermal (CPG) systems reinject
the produced CO2, eventually sequestering all CO2 underground. Extracting the
geothermal energy from the CCS reservoir results in additional CO2 storage poten-
tial, as, for example, the CO2 density increases and the overall reservoir pressure
decreases. The CPG-generated heat, electricity, and/or revenue could “subsidise”
CCS operations. Consequently, CPG could increase both the geothermal energy
and the CCS capacities.
Our CPG feasibility study combines an integrated production system modeling
approach with a history-matched reservoir model of an active CCS site (Aquistore,
Canada). The integrated modeling approach is used to account for all relevant
processes, from well-bore pressure and temperature drops to multi-phase, multi-
component fluid flow in the reservoir to fluid separation, power generation, and
continuous with reinjection of CO2 at the land surface, in a fully implicit matter.
Our results suggest that stable CO2 circulation, extracting geothermal energy
between the underground CO2 plume in the saline reservoir and the land surface,
is possible. Furthermore, we see additional CO2 storage potential, caused by the
circulation of CO2. Our simulations indicate that Aquistore may provide a unique
opportunity for pioneering a CPG field test.

How to cite: Hau, K. P., Brehme, M., Rangriz-Shokri, A., Malakooti, R., Nickel, E., Chalaturnyk, R. J., and Saar, M. O.: Integrated reservoir and production system modeling of geothermal energy extraction at the Aquistore CCS site in Canada, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19289, https://doi.org/10.5194/egusphere-egu24-19289, 2024.

EGU24-21446 | ECS | Posters on site | ERE2.10

The Geothermal Paradox of Choice: A Comparative Techno-Economic Assessment of Geothermal Energy Production for Heat and Power Applications 

Nicolas Rangel Jurado, Serhat Kucuk, Daniel Pokras, Denise Degen, Federico Games, Maren Brehme, and Martin Saar

Geothermal energy is poised to play a pivotal role in the renewable energy transition by providing baseload, dispatchable, and carbon-free heat and power. Nonetheless, in contrast to its renewable energy alternatives, such as solar or wind, geothermal energy is harnessed beneath the Earth’s surface, inherently increasing the challenges, risks, uncertainties, and opportunities related to its exploration and utilization. As a result, numerous concepts and field development strategies for exploiting geothermal energy have been proposed over the last century. The seemingly overwhelming abundance of choices has prompted widespread confusion regarding the optimum approach to developing geothermal energy across multiple sectors. In this study, we attempt to answer this question by conducting a scenario analysis consisting of three geological reservoirs developed through various geothermal technologies to generate heat and electricity. Stochastic analyses for each of the geological reservoirs considered is also performed in a second set of simulations to account for subsurface uncertainties. Using a combination of advanced numerical simulators, we evaluate and compare the techno-economic performance of water-based geothermal systems (i.e., Conventional Hydrothermal Systems, Enhanced Geothermal Systems (EGS) and Advanced Geothermal Systems (AGS)) against their conceptual counterparts that use CO2 as the subsurface working fluid (i.e., CO2 Plume Geothermal (CPG), CO2-EGS, and CO2-AGS). Our results show that water-based energy extraction and open-loop configurations distinctly favor higher production temperatures owing to the superior thermodynamic properties of water and the ability to accommodate larger reservoir volumes, respectively. However, these operating conditions also exhibit lower heat-to-electricity conversion efficiencies, thereby significantly impacting economic returns when electricity generation is intended. In contrast, the value of CO2-based energy extraction and closed-loop configurations, to some extent overlooked in direct-heat-use applications, is considerably highlighted when targeting electricity production. Our work underscores the critical interplay between a geothermal reservoir's thermal and hydraulic performances across various system types. A comprehensive analysis of the relationships exposed in this study can assist geothermal operators in selecting appropriate end-user applications, predicting long-term reservoir performance, and ultimately enhancing the economic success of geothermal projects.

How to cite: Rangel Jurado, N., Kucuk, S., Pokras, D., Degen, D., Games, F., Brehme, M., and Saar, M.: The Geothermal Paradox of Choice: A Comparative Techno-Economic Assessment of Geothermal Energy Production for Heat and Power Applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21446, https://doi.org/10.5194/egusphere-egu24-21446, 2024.

EGU24-21517 | Posters on site | ERE2.10

Techno-economic Analysis of Geothermal Operations Utilizing Carbon Dioxide 

Tsubasa Onishi, Morteza Esmaeilpour, Allan Leal, Powei Huang, and Martin Saar

Sustainable geo-energy technologies, including geothermal energy, hydrogen/carbon dioxide capture, utilization, and storage, and aquifer thermal energy storage, have received significant attention from the global scientific community and industry due to their pivotal roles in achieving international decarbonization targets. While numerous stand-alone simulation tools to assess the feasibility of these geo-energy systems have been developed, existing tools often focus on simulating individual components, such as subsurface, wellbore, surface, and economic. Relying solely on such tools tends to overlook the comprehensive techno-economic evaluation of these integrated geo-energy systems. Although some simulation tools with integrated modeling capabilities exist, their flexibility and extendibility to various geo-energy systems remain limited. We present TANGO, an acronym for Techno-economic ANalysis of Geo-energy Operations, which is a newly developed integrated techno-economic simulation tool designed to offer flexibility, allowing for a comprehensive evaluation of various geo-energy operations across different fidelity levels. The applications of TANGO to a series of numerical examples of geothermal systems utilizing carbon dioxide (e.g. CO2 Plume Geothermal – CPG), ranging from rapid site screening with the low fidelity modeling capability to detailed simulation studies using the high-fidelity modeling capability, will be presented to demonstrate TANGO’s distinctive features and capabilities.

How to cite: Onishi, T., Esmaeilpour, M., Leal, A., Huang, P., and Saar, M.: Techno-economic Analysis of Geothermal Operations Utilizing Carbon Dioxide, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21517, https://doi.org/10.5194/egusphere-egu24-21517, 2024.

EGU24-4289 | ECS | Orals | AS2.2

Modelling of urban lake breeze circulation: the implications on urban heat island mitigation 

Qilong Zhong, Jiyun Song, Xiaoxue Wang, and Yuguo Li

Recent years have seen more intense and frequent heatwaves across the globe. Urban overheating phenomenon induced by global warming and urban heat island (UHI) effect has adverse impact on human health. In particular, compact high-rise cities witnessed worsened wind environment, exacerbating the UHI phenomenon. Blue space such as urban lakes may help mitigate the UHI effect and improve citizens’ living environment. Under weak synoptic wind conditions, the temperature difference between built-up areas and lakes can induce wind circulation, known as lake-breeze circulation (LBC). The LBC system can transport cool and fresh air from lake surfaces into built-up areas, reducing urban air temperature and improving urban wind environment, while increasing urban air humidity. In this study, we developed a multi-scale water-energy coupled CFD model to simulate the transport processes of heat and moisture between lake surfaces and built-up areas within the urban boundary layer. The model adopted a porous turbulence model to simulate the entire urban canopy layer, a lake evaporation model and a species transport model to simulate lake dynamics, and a coordinate transformation method to simulate the effect of the background atmosphere. The model features the capability of resolving dynamics of atmospheric temperature, humidity, and wind at both street canyon scale (1 m) and city scale (50 km) with relatively low computational costs. Based on this model, we conducted sensitivity analysis to investigate the impact of urban parameters (e.g., city scale, building height and density, anthropogenic activities) and lake parameters (e.g., lake scale and lake surface temperature) on the spatial variation of temperature, humidity, wind, and thermal comfort index. Our results can provide significant references for urban planning and city design for sake of UHI mitigation.

How to cite: Zhong, Q., Song, J., Wang, X., and Li, Y.: Modelling of urban lake breeze circulation: the implications on urban heat island mitigation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4289, https://doi.org/10.5194/egusphere-egu24-4289, 2024.

EGU24-4829 | ECS | Orals | AS2.2

A one-dimensional urban flow model with an Eddy-diffusivity Mass-flux (EDMF) scheme and refined turbulent transport (MLUCM v3.0) 

Jiachen Lu, Negin Nazarian, Melissa Hart, and Scott Krayenhoff

In recent years, urban canopy models (UCMs) have been used as fully coupled components of mesoscale atmospheric models as well as offline tools to estimate temperature and surface fluxes using atmospheric forcings. Examples include multi-layer urban canopy models (MLUCMs), where the vertical variability of turbulent fluxes is calculated by solving prognostic momentum and turbulent kinetic energy (TKE, $k$) equations using length scale ($l$) and drag parameterizations. These parameterizations are based on the well-established 1.5-order $k-l$ turbulence closure theory and are often informed by microscale fluid dynamics simulations. However, this approach can include simplifications such as the assumption of the same diffusion coefficient for momentum, TKE, and scalars. In addition, the dispersive stresses arising from spatially-averaged flow properties have been parameterized together with the turbulent fluxes while being controlled by different mechanisms. Both of these assumptions impact the quantification of turbulent exchange of flow properties and subsequent air temperature prediction in urban canopies. To assess these assumptions and improve corresponding parameterization, we conducted 49 large-eddy simulations (LES) for idealized urban arrays, encompassing variable building height distributions and a comprehensive range of urban densities ($\lambda_p\in[0.0625,0.64]$) seen in global cities. We find that the efficiency of turbulent transport (numerically described via diffusion coefficients) is similar for scalars and momentum but 3.5 times higher for TKE. Additionally, the parameterization of the dispersive momentum flux using the $k-l$ closure was a source of error, while scaling with the pressure gradient and urban morphological parameters appears more appropriate. In response to these findings, we propose two changes to MLUCM v2.0: (a) separate characterization for turbulent diffusion coefficient for momentum and TKE; and (b) introduction of an explicit physics-based "mass flux" term to represent the non-Gaussian component of the dispersive momentum transport as an amendment to the existing "eddy diffusivity" framework. The updated one-dimensional model, after being tuned for building height variability, is further compared against the original LES results and demonstrates improved performance in predicting vertical turbulent exchange in urban canopies.

How to cite: Lu, J., Nazarian, N., Hart, M., and Krayenhoff, S.: A one-dimensional urban flow model with an Eddy-diffusivity Mass-flux (EDMF) scheme and refined turbulent transport (MLUCM v3.0), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4829, https://doi.org/10.5194/egusphere-egu24-4829, 2024.

EGU24-5608 | ECS | Orals | AS2.2

Impacts of urban development on the local weather: A comprehensive analysis from 1970 to 2020 in Madrid. 

Juan Carbone, Beatriz Sánchez, Carlos Román-Cascón, Alberto Martilli, Dominic Royé, and Carlos Yagüe

The proportion of the world’s population living in cities has increased from 37% to 56% over the last 50 years, and it is expected to continue rising further to 60% by 2030 (UN, 2022). As an essential effect of this evolution, urban land cover has expanded rapidly. In the case of Madrid, the increase in urban fraction during the period from 1970 to 2020 has been 20%. It is well known that urbanization reduces the vegetated cover and modifies surfaces properties altering the surface-atmosphere interactions and the different terms of the Surface Energy Balnace (SEB) compared to nearby rural areas. Therefore, analyzing the influence of these changes in urban land cover contributes to understand the potential risks that urban residents might face considering the urban grown and the expected temperatures increases, as this has adverse impacts on human health, livelihoods, and key urban infrastructure.

The aim of the present study is to examine the consequence of Madrid's urban growth on the near-surface air temperature and on the SEB. We conduct a modeling study using WRF-ARW with the multilayer urban parameterization BEP-BEM, in which the land use and the land cover have been modified according to urban expansion in Madrid and its surroundings from 1970 to 2020. Two scenarios of common meteorological conditions of special interest are selected for this study: a period of intense heatwave during the summer season and a short period of strongly stable atmospheric conditions in winter, both observed in 2020. The results show that in areas where the urban fraction become greater an increase in near-surface air temperature is found for both simulated periods, especially during the night, pointing out that the cooling rate decreases in urban areas. The growing of urban land cover over time also modifies the SEB and turbulent transport in Madrid and surroundings, leading to an increase in temperatures, specially for the minima ones.

How to cite: Carbone, J., Sánchez, B., Román-Cascón, C., Martilli, A., Royé, D., and Yagüe, C.: Impacts of urban development on the local weather: A comprehensive analysis from 1970 to 2020 in Madrid., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5608, https://doi.org/10.5194/egusphere-egu24-5608, 2024.

EGU24-6308 | ECS | Orals | AS2.2

The Implementation of the BEP+BEM Offline Parameterization Scheme: Exploring Urban Dynamics through Climatic Projections 

Gianluca Pappaccogli, Andrea Zonato, Alberto Martilli, Riccardo Buccolieri, and Piero Lionello

As climate change continues to exert an impact on urban areas, the comprehension of its effects on the urban environment becomes crucial for sustainable urban planning. This study presents a novel approach employing the Building Effect Parameterization (BEP) coupled with a Building Energy Model (BEM) in an offline configuration to simulate urban climates. The multi-layer BEP+BEM model, properly describes the vertical arrangement of urban fabric, accounting for the distribution of heat, moisture, and momentum sources throughout the urban canopy layer. Additionally, energy consumption within buildings for both cooling and heating is estimated by the BEM, providing a comprehensive perspective on the urban energy balance. Coupled with a 1-D column model of urban canopy flow, the BEP+BEM offline model accurately estimates drag coefficients and turbulent length scales based on urban fabric characteristics. In the proposed version, the model has been extended to consider additional factors such as green areas and street trees, along with existing green roofs, photovoltaic panels and the permeability of urban materials. This expansion enhances the model's capability to assess the effectiveness of sustainable infrastructure in mitigating climate change effects on urban areas. In this study, the BEP+BEM scheme is forced by data from climate projections, allowing for the dynamic representation of various Local Climate Zones (LCZs) under distinct climatic conditions. Simulations in different LCZs and under different climatic conditions are compared to evaluate the impact of climate change on urban environment, enabling the exploration of how different urban areas respond to changing meteorological forcings. The sensitivity analysis includes a range of standard urban typologies (i.e. LCZs), capturing the complexity of interactions between the built environment and the atmosphere. This approach offers an assessment of the impacts of climate change on key urban phenomena, such as urban heat islands (UHI), thermal discomfort, and heightened energy consumption by buildings. The outcomes of this study provide valuable insights for the urban climate community, policymakers, and researchers with the aim of enhancing the resilience of cities in the face of a changing climate. By bridging the gap between climate projections and urban climate simulations, a consistent framework is presented in this work for evaluating and adapting various urban environments to future climatic conditions.

How to cite: Pappaccogli, G., Zonato, A., Martilli, A., Buccolieri, R., and Lionello, P.: The Implementation of the BEP+BEM Offline Parameterization Scheme: Exploring Urban Dynamics through Climatic Projections, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6308, https://doi.org/10.5194/egusphere-egu24-6308, 2024.

EGU24-7011 | Orals | AS2.2

UrbanTALES: A comprehensive dataset of Urban Turbulent Airflow using systematic Large Eddy Simulations 

Negin Nazarian, Jiachen Lu, Melissa Hart, and E. Scott Krayenhoff

The urban canopy layer (UCL) is characterized by a heterogeneous flow pattern that responds to heterogeneous urban geometries. The varying heights and layouts of buildings play a pivotal role in shaping this spatial variability, as they block, divert, and slow wind and determine the exchange of momentum and energy above the urban canopy. When representing these complex dynamics, however, research has conventionally relied on microscale simulations conducted over limited (often idealized) building arrays. Extending the findings to realistic urban neighborhoods and urban parameterizations presents a clear limitation, as evidenced by discrepancies in multi-model comparisons with observational data in cities.

More extensive datasets of urban airflow are needed to cover a range of realistic urban neighborhoods and provide a more holistic analysis of turbulent flow in different urban characteristics. Responding to this gap in the field, we developed a historically extensive and comprehensive dataset of Urban Turbulent Airflow based on state-of-the-art  Large Eddy Simulations (UrbanTALES). The dataset includes 400 urban layouts with both idealized and realistic configurations. Realistic urban neighborhoods were obtained from major cities worldwide, incorporating variations in plan area densities [0.0625-0.64] and height distributions [4-70m]. Idealized urban arrays, on the other hand, include two commonly studied configurations (aligned and staggered arrays), featuring both uniform and variable height scenarios along with oblique wind directions. 

UrbanTALES offers canopy-averaged data as well as 2D and 3D flow fields tailored for different applications in urban climate research. The dataset provides time-averaged wind flow properties, as well as second- and third-order flow moments that are critical for understanding turbulent processes in the UCL. Here, we describe the UrbanTALES dataset and its application, noting the unique opportunity to deploy a comprehensive representation of realistic urban neighborhoods for a) revisiting neighborhood-scale urban canopy parameterizations in various models and b) informing in-canopy flow and turbulent analyses. Furthermore, we discuss the application of this dataset for training Machine Learning algorithms for pedestrian wind speed. 

How to cite: Nazarian, N., Lu, J., Hart, M., and Krayenhoff, E. S.: UrbanTALES: A comprehensive dataset of Urban Turbulent Airflow using systematic Large Eddy Simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7011, https://doi.org/10.5194/egusphere-egu24-7011, 2024.

EGU24-7970 | ECS | Posters on site | AS2.2

Can urban heating inadvertently induce urban cooling? 

Klaas Laan and Dilia Kool

EGU24-7970

Can urban heating inadvertently induce urban cooling?

Klaas Laan and Dilia Kool

 

Cities are getting hotter—and will continue to get hotter with projected climate change and increases in urbanization. However, is it possible that rising temperatures present an opportunity for enhanced evaporative cooling? Evaporative cooling generally increases linearly with an increase in the vegetative fraction. But it is also well documented that this linearity breaks down at a certain point, and that as the vegetation becomes denser, the relative increase in evapotranspiration becomes more marginal. One possible explanation is the known phenomenon that lateral heat advection enhances evapotranspiration from “scattered” or “patchy” vegetation. Lateral heat advection occurs when there is a large temperature contrast between hot, non-vegetated surfaces and much cooler vegetated surfaces. Lateral heat advection is expected to be larger at lower vegetation fractions (more source areas) and in climates that have more extreme temperatures (arid regions, future climate change-affected areas (?)). We expect that potential evaporation per unit area, enhanced by lateral heat advection, will be inversely proportional to the vegetation fraction. Thus, higher temperatures and lower vegetation fractions would result in higher evaporative cooling per unit vegetated area. This, then, could explain the non-linear relationship between evaporative cooling and vegetation fraction.

We here present a novel analysis of the dynamics of potential and actual evapotranspiration as a function of vegetation fraction using an existing urban energy balance dataset for 13 locations representing a range of climate conditions (Lipson et al., 2022; doi 10.5194/essd-14-5157-2022). A separate assessment of the horizontal component of potential evaporation and its potential implications for enhanced evaporation sheds light on whether urban heating could, to some extent, induce urban cooling.

How to cite: Laan, K. and Kool, D.: Can urban heating inadvertently induce urban cooling?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7970, https://doi.org/10.5194/egusphere-egu24-7970, 2024.

EGU24-13329 | Posters on site | AS2.2

A Versatile Reduced Order Model of Urban Boundary Layer Dynamics in the Center of Paris 

Konstantin Kuznetsov, Paul Sylvestre, Pavel Litvinov, Oleg Dubovik, and David Fuertes

The computational demands of Computational Fluid Dynamics (CFD) often limit its real-time or large-scale applications, particularly in scenarios requiring multiple simulations based on varying input parameters. This study introduces a surrogate reduced order model (ROM) that not only addresses the computational challenges of CFD but also underscores its potential for broad applicability.

We focus on the dynamics of the Urban Boundary Layer (UBL), a key factor in understanding urban microclimates and their impact on energy consumption, thermal comfort, and local weather phenomena. Using a representative urban test case from the city center of Paris, we illustrate the effectiveness of our approach. During the offline phase, the ROM is constructed by assembling a database of Dynamic Mode Decomposition (DMD) modes [1] associated with various aspects of UBL dynamics, such as temperature distribution, wind patterns, and turbulence characteristics. These modes are determined based on a set of meteorological conditions defined through k-means clustering analysis. During the online phase, we interpolate these DMD modes from the database, enabling us to determine the dynamic characteristics of the UBL within the domain without initiating computationally intensive code_saturne calculations.

Our validation for the UBL dynamics in central Paris indicates that the online phase can achieve a Normalized Root Mean Square Error (NRMSE) of 2-8%. A distinctive aspect of our approach is the incorporation of DMD during the code_saturne computation process. Some modifications of DMD can be seamlessly integrated into numerous code_saturne simulations, harnessing the advantages of DMD with minimal computational trade-offs. This ROM approach offers a promising tool for urban climate studies, urban planning, and environmental management, providing a more efficient means to simulate and understand the complex dynamics of the Urban Boundary Layer.

How to cite: Kuznetsov, K., Sylvestre, P., Litvinov, P., Dubovik, O., and Fuertes, D.: A Versatile Reduced Order Model of Urban Boundary Layer Dynamics in the Center of Paris, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13329, https://doi.org/10.5194/egusphere-egu24-13329, 2024.

EGU24-15662 | ECS | Posters on site | AS2.2

How does urbanization shape the record-breaking temperatures in Izmir, Turkey ? 

Fatma Başak Saka and Yurdanur Unal

The urban heat island effect, denoting the temperature difference between urban and rural areas, has become more widely recognized due to the increasing urbanization over the years. Recent studies related to the urban heat island effect mainly focus on changes in atmospheric changes and their role in triggering significant weather phenomena. Understanding these dynamics is crucial for making future projections. This research is motivated by the need to understand how the urban heat island intensity affects the boundary layer and temperature structure of İzmir, Türkiye during a record-breaking temperature period, in July 2023.  Temperatures in the Aegion region for July 2023 are above season normals of the 1991-2020 period by 1.7ºC. To investigate how urbanization contributed to the temperature changes the chosen timeframe is modeled using the Weather Research and Forecasting (WRF) Model (version 4.3). To enhance spatial resolution, we integrated the Coordination of Information on the Environment (CORINE) land cover data into the model, employing a nested domain setup ranging from outer to inner domains with resolutions of 9-3-1 km. ERA5 Reanalysis was chosen as the initial condition to force the model throughout the selected period. Following the simulations using the parameterizations set optimized for the Izmir region in July 2023, the obtained results were scrutinized through a comparison with data from meteorological observation stations to analyze the accuracy and performance of the simulations.    Then, to examine how urban areas affect atmospheric behavior under record-breaking conditions, atmospheric conditions of  July 2003 were simulated by utilizing the same parameterizations and boundary conditions with altered land use categories.   The urban land-use categories within the domain were changed to the most dominant rural land-use category.   In evaluating the city's influence on record-breaking temperatures, the analysis focused on changes in the atmospheric boundary layer and its associated parameters by comparing the simulations with urbanizations and without urbanization in İzmir.

How to cite: Saka, F. B. and Unal, Y.: How does urbanization shape the record-breaking temperatures in Izmir, Turkey ?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15662, https://doi.org/10.5194/egusphere-egu24-15662, 2024.

EGU24-16346 | ECS | Posters on site | AS2.2

Urban roughness sublayer characteristics: sensitivity to planetary boundary layer schemes and multi-layer urban models 

Wanliang Zhang, Jimmy Chi Hung Fung, and Mau Fung Michael Wong

The Pearl River Delta (PRD) region in China is characterized by a large fraction of urbanized areas of which the growth rate is unprecedented. Modelling a realistic meteorological field for such a region is challenging mainly due to the uncertainties in the meso-scale numerical model, and the paucity of high-resolution profiler-type observations. In this study, we aim to improve the understanding of the urban effects on the modelled meteorological field in the PRD region by applying different fine-tuned planetary boundary layer (PBL) schemes coupled with two multi-layer urban models and leveraging the high spatial-temporal wind LiDAR observations. Particularly, the momentum in the urban roughness sublayer (RSL, about three times the building height) will be thoroughly investigated using long-lasting profiler-type observations.

The Weather Research and Forecast (WRF) model offers a variety of PBL schemes which may feature a non-local transport algorithm under unstable atmospheric conditions. Most PBL schemes utilize the surface layer fluxes calculated based on the Monin-Obukhov similarity theory, acting on the first model layer only. Although this bulk parameterization of surface layer fluxes is appropriate for urban areas occupied predominantly by low-rise buildings, it is unable to reflect the momentum drag and thermal exchange processes when the average building height (H) within a model cell greatly exceeds the height of the lowest model. Multi-layer urban models, Building Effects Parameterization (BEP), and Building Energy Model (BEM) can be coupled with PBL schemes to provide a more realistic interaction between buildings and air within the RSL. Required input for initializing the multi-layer urban models include H and average street width, which can be simply prescribed (assumed) or derived from the local climate zones.

Despite many efforts have been made to study the improvements by urban models on the surface meteorological variables, such as 10-m wind speed, 2-m temperature and moisture, little investigation of modelled results has been carried out focusing on the RSL and the entire boundary layer over a long-time series due to scarce observations. Recently, three wind LiDAR units were deployed in Hong Kong, providing us with a valuable opportunity to monitor wind profile evolution continuously at a 25-m and 1-hr resolution and to reveal the transport of surface layer fluxes to the overlying RSL.  In the result section, we first present the wind speed profiles to understand the benefits of a multi-layer urban model compared to the bulk parameterization, justified by the LiDAR observations. Secondly, as the non-local PBL scheme can transport the surface fluxes to non-adjacent cells, a comparison of the momentum flux profile will be presented between local and non-local PBL schemes under different stabilities.

How to cite: Zhang, W., Fung, J. C. H., and Wong, M. F. M.: Urban roughness sublayer characteristics: sensitivity to planetary boundary layer schemes and multi-layer urban models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16346, https://doi.org/10.5194/egusphere-egu24-16346, 2024.

EGU24-16420 | Orals | AS2.2

Representing mean wind speed profile over urban canopy with building height variability 

Keisuke Nakao, Hideki Kikumoto, Hiroshi Takimoto, Jia Hongyuan, and Wang Xiang

 The horizontal mean wind speed profile in vertical direction within and above urban canopy (UC) is an essential information to drive the exchange of momentum, heat, moisture and pollutants in atmosphere. Well-known profiles in logarithmic and exponential layers, which express upper and lower wind over UC, respectively, are efficient assumptions used to express UC wind profile.

 This study attempted to add the intermediate layer (IL) between those two-layers to include the effect of building height variability on the mean wind speed profile. Large-eddy simulations (LESs) of UC with building height variability were conducted using a wide range of morphology parameters, that is, plan area index, aspect ratio, and the standard deviation of building height.

 A tendency of the bulk drag coefficient of the IL was expressed by the plan area index and the frontal area index at the intermediate layer. The wind speed at IL was modeled linearly by the length- and velocity-scale analysis. By parameterizing the coefficients of these three layers, we attempted to analytically represent an entire wind speed profile by the three-layer wind profiles. The results indicated reasonable consistency in the wind speeds at mean building height and the momentum flux with LES data. Effect of the thermal stratification was investigated by the correction of the length-scale in IL.

How to cite: Nakao, K., Kikumoto, H., Takimoto, H., Hongyuan, J., and Xiang, W.: Representing mean wind speed profile over urban canopy with building height variability, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16420, https://doi.org/10.5194/egusphere-egu24-16420, 2024.

EGU24-16891 | ECS | Orals | AS2.2

A systematic investigation of urban modifications of mixed layer height and cloud cover in Berlin, Germany 

Daniel Fenner, Andreas Christen, Russell Glazer, Sue Grimmond, Simone Kotthaus, Dana Looschelders, Fred Meier, William Morrison, and Matthias Zeeman

In order to better understand how urban areas modify the regional atmospheric boundary layer (ABL) and to improve and evaluate weather and climate models for urban applications and services, detailed ABL observations are needed. With new instrument technologies and advanced automatic algorithms for detection of aerosols, mixed-layer height (MLH) and boundary-layer clouds, ground-based remote sensing instruments are increasingly used in urban observational networks.

During a one-year measurement campaign in Berlin, Germany (urbisphere-Berlin, Autumn 2021 – Autumn 2022), a variety of ground-based ABL observations were carried out in the greater Berlin region. Berlin as an isolated continental city with approximately 3.8 million inhabitants provides a fairly homogeneous rural background. The urbisphere network included five inner-city, six outer-city and 14 rural sites equipped with continuously-operated Automatic Lidar and Ceilometers (ALC). The measurement network was designed and set up in a systematic and rigorous manner in order to capture intra-urban, urban-rural, and upwind-city-downwind effects of MLH, cloud-base height (CBH), and cloud cover fraction (CCF) along several transects as air masses move over the city. Based on the ALC observations, MLH, CBH and CCF were automatically derived. ALC observations are complemented by measurements of wind and temperature profiles over the city using Doppler-Wind Lidars and radiosondes concurrently released in urban and rural locations during selected days. Surface heat fluxes are continuously measured with six eddy-covariance flux towers and seven path-averaging scintillometers in urban and rural settings.

This contribution highlights the scientific considerations of the systematic measurement network design and the corresponding data analysis. We are proposing a scheme of attributing measurements to rings around the city centre representing the inner city (radius of 6 km), the outer city (radius of 18 km) and rural areas (radius of 90 km), further separated into upwind, downwind and other sectors. A detailed statistical analysis of the year-long dataset finds differences in MLH, CBH and CCF during different seasons and under different weather forcings. Selected case-study days are analysed in more detail to understand the processes controlling the interactions between surface fluxes and mixed-layer dynamics. These days are further used to evaluate the forecasting skill of hectometric dynamical-modelling runs with regard to ABL dynamics, quantifying also the sensitivity of ABL dynamics in the model to surface representation (e.g. soil moisture, heat flux partitioning).

How to cite: Fenner, D., Christen, A., Glazer, R., Grimmond, S., Kotthaus, S., Looschelders, D., Meier, F., Morrison, W., and Zeeman, M.: A systematic investigation of urban modifications of mixed layer height and cloud cover in Berlin, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16891, https://doi.org/10.5194/egusphere-egu24-16891, 2024.

EGU24-17628 | ECS | Posters on site | AS2.2

Large-Eddy Simulations of Methane Dispersion at the Utrecht University Campus 

Steven van der Linden, Judith Tettenborn, Thomas Röckmann, Stephan de Roode, and Bas van de Wiel

Last June 2023 a controlled release experiment (CRE) of methane was conducted at the campus of the Utrecht University, the Netherlands, with the aim of improving models for emission quantification. The methane was released at different flow rates and subsequently measured in the local area (along closed paths of approximately 500 m length) using vehicle mounted sensors. In addition, several wind sensors were deployed at approximately 35 meters distance of the release location covering the dominant flow pathways between the buildings.

Although the setup enables us to relate the variability in wind direction and concentration peaks in the direct vicinity of the release, the limited spatial extent of the setup still makes it challenging to determine the dispersion of methane on the larger campus scale. Therefore, we explore the possibility to use meter-scale Large-Eddy Simulations (LES) in which the flow around the buildings is explicitly resolved with an immersed boundary method. With this approach, we aim to provide detailed information on the dispersion of methane ranging from the street-level to the campus scale.

Here, we will show the first results of our simulations and a comparison with the observations. The controlled release experiment and wind measurements serve as validation for the LES, with the LES ideally reproducing the observed concentrations and wind directions in a statistical sense. We will discuss the model complexity required to accurately model observed dispersion features and look at the dependence of this result to changes in model setup. For example, how the model result changes with respect to a change in the prescription of large-scale meteorological conditions.

Such validated urban LES may in the future be used not only for forward-in-time prediction of pollutant concentrations but also for inverse modelling to estimate the location of pollutant release, when only a limited number of observations are available.

How to cite: van der Linden, S., Tettenborn, J., Röckmann, T., de Roode, S., and van de Wiel, B.: Large-Eddy Simulations of Methane Dispersion at the Utrecht University Campus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17628, https://doi.org/10.5194/egusphere-egu24-17628, 2024.

EGU24-17845 | Orals | AS2.2

Can a city modify a severe convective windstorm? 

Francesco De Martin, Andrea Zonato, and Silvana Di Sabatino

It is well known that cities can modify the rainfall distributions, in particular deep moist convection is more frequently triggered over and downwind urban areas. However, the effect of cities on the most extreme convective events, such as hailstorms, downbursts or tornadoes, is poorly studied. This topic needs further investigation since exposure and vulnerability to severe storm risk is larger in cities than in the surrounding rural area. What happens if a severe convective windstorm impacts a big city? Is the storm modified by the urban land use?

Our analysis focuses on a case study that occurred on 25 July 2023, when a nocturnal downburst affected the city of Milan, in northern Italy, with measured wind gusts up to 30 m/s. The intense wind gusts downed many trees in the public parks and over the streets, blocking urban mobility. The event is investigated in depth using both observations and high-resolution numerical simulations performed with the WRF model.

Observations show that a UHI over Milan before the storm was negligible, while there was a drier air mass over the city than over the surrounding rural area. Consequently, a pool with low values of equivalent potential temperature (theta-e), a quantity that strongly influences deep moist convection, was present over the city.

Four nested WRF simulations are carried out with grid resolution from 9 km up to 333 m, and 64 vertical levels starting from 5m AGL. Two different boundary layer parametrizations are tested, namely MYJ and BouLac schemes, as well as two different microphysics schemes: Thompson and WRF Single-moment 6-class. Moreover, simulations with bulk urban parametrizations are compared with those coupled with the building effect parameterization and the building energy model (BEP-BEM), employing data of the World Urban Database and Access Portal Tools (WUDAPT).  Simulations without the urban land use (no-urban) are carried out to test the effect of the Milan urban area on the convective storm. Results of all these simulations are compared with surface observations and radar data. The simulations have a similar skill, with slightly better results using the BouLac scheme coupled with BEP-BEM. Simulations using urban parametrizations are able to reproduce the pre-storm pool with low theta-e values over Milan, while no-urban simulations do not simulate the low theta-e pool.

All WRF simulations accurately reproduce the violent windstorm, both in terms of simulated wind gusts, rainfalls and radar reflectivity. Removing the city, stronger wind gusts are simulated at the surface due to the significantly reduced drag. However, rainfalls are slightly intensified downwind of the city, as well as the drop of potential temperatures associated with the downdrafts.

In conclusion, the urban canopy may have prevented the development of even more violent wind gusts in the city, due to the increased surface roughness. On the other hand, despite the presence of a pool of low theta-e values, the storm likely intensified downwind the city. A possible motivation to that intensification will be proposed in the presentation. 

How to cite: De Martin, F., Zonato, A., and Di Sabatino, S.: Can a city modify a severe convective windstorm?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17845, https://doi.org/10.5194/egusphere-egu24-17845, 2024.

EGU24-18040 | Orals | AS2.2

Linking synoptic flow and city dynamics: PANAME observations of the Paris urban boundary layer   

Simone Kotthaus, Martial Haeffelin, Jonnathan Céspedes, Jean-François Ribaud, Jean-Charles Dupont, Marc-Antoine Drouin, Pauline Martinet, and Aude Lemonsu

Atmospheric boundary layer dynamics form in response to synoptic flow and surface-atmosphere exchanges. Over cities, the complex roughness and additional heat from storage and anthropogenic emissions clearly affect atmospheric stability, with implications for heat risk and pollution dispersion. This work examines how the specific dynamics of the Paris region urban atmosphere interact with the synoptic flow using observations from a dense measurement network.

The interdisciplinary PANAME initiative is a framework coordinating the synergy of numerous projects that are studying the Paris atmosphere using both numerical modelling at various scales and novel observations. The measurement network not only includes dense surface station measurements and turbulent flux towers, but also ground-based atmospheric profile remote sensing and additional radiosonde measurements within the city. This work exploits observations from automatic lidars and ceilometers (ALC), Doppler wind lidars (DWL), and microwave radiometers (MWR) that are operated along a suburban-urban transect to collect simultaneous profiles of air temperature, wind, turbulence, and aerosol characteristics at high vertical and temporal resolution. The continuous observations from a network of compact ground-based remote sensing instruments are shown to be extremely valuable for an improved understanding of the complex processes that govern the urban atmosphere as they are highly variable in space and time.

The complex dynamics of the urban atmospheric boundary layer are explored through advanced measurement products, such as low-level jet characteristics and mixed layer heights. We evaluate how different indicators of atmospheric stability from synergy of multiple remote sensing profile data can portray the spatial and temporal variations in urban boundary layer dynamics. The work highlights the importance of atmospheric boundary layer dynamics as a crucial driver for near-surface conditions.

How to cite: Kotthaus, S., Haeffelin, M., Céspedes, J., Ribaud, J.-F., Dupont, J.-C., Drouin, M.-A., Martinet, P., and Lemonsu, A.: Linking synoptic flow and city dynamics: PANAME observations of the Paris urban boundary layer  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18040, https://doi.org/10.5194/egusphere-egu24-18040, 2024.

EGU24-18319 | ECS | Orals | AS2.2

Wind tunnel study on the influence of vegetation density and wind direction on urban canyon ventilation 

Annika Vittoria Del Ponte, Sofia Fellini, Massimo Marro, Pietro Salizzoni, and Luca Ridolfi

Inserting vegetation within the urban environment mitigates the urban heat island effect, the flooding risk, and improves air quality. However, its aerodynamic effect has remarkable impact on the pollutant transport and, consequently, on human health comfort. Indeed, the presence of vegetation within an urban canyon leads to non-trivial patterns of pollutant concentration and mass fluxes, as a consequence of complex mean and turbulent velocity fields. In addition to the vegetation density, the flow structure within canyons is influenced by their geometry and by the wind direction.

   The aim of the present study is to experimentally investigate the velocity field within a canyon, varying the vegetation density and the wind direction. We measured flow velocity statistics within an indefinitely long street canyon, with unit height-to-width ratio, subject to a neutrally stratified boundary layer modeled in the wind tunnel of École Centrale de Lyon. The aerodynamic impact of vegetation was reproduced by inserting plastic miniatures of trees along the two long sides of the canyon. We considered an empty canyon and a vegetated canyon, whose longitudinal axes are oriented with angles of 0°, 30°, and 60° with respect to the external wind flow.

  Results reveal that when the canyon is inclined with respect to the external wind direction the mean flow follows a complex helicoidal structure. The presence of trees decreases significantly the mean longitudinal velocity and weakens the transversal circulation in the inclined canyon. The dampening effect of the mean longitudinal flow is more marked increasing the inclination angle of the canyon. Turbulent fluctuations are enhanced above the tree crowns, mostly when the wind blows parallel to the canyon axis. On the contrary, turbulent fluctuations decreases at tree trunk and crown levels, in particular when the canyon is inclined of 60° with respect to the external wind direction. Spectra of the velocity signal show that the presence of trees induces an evident shift of the energy peak towards high frequencies.

  The collected data constitute a step forward to understand and modeling the urban microclimate.

How to cite: Del Ponte, A. V., Fellini, S., Marro, M., Salizzoni, P., and Ridolfi, L.: Wind tunnel study on the influence of vegetation density and wind direction on urban canyon ventilation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18319, https://doi.org/10.5194/egusphere-egu24-18319, 2024.

In this work, various very-high-resolution simulations with the Harmonie-AROME Numerical Weather Prediction (NWP) model are performed for the city of Paris during an intense heatwave event in the summer of 2022, to evaluate the capability of the model to reproduce real conditions, at various resolutions and incorporating different kinds of landuse and urban morphology types.

 

In particular, simulations are performed using ECWMF operational forecasts at 9 km resolution as boundary conditions, for the operational 2.5 km runs. Moreover, two 500 m and 100 m resolution domains have been one-way nested in the parent one.

For considering the impact of urban areas, the state-of-the-art urban canopy parameterization Town Energy Balance (TEB, Masson et al., 2000), has been employed within the modeling system, and its single-layer and multi-layer options have been compared to evaluate the improvements brought by the multi-layer capability.

 

To test the impact of various urban morphologies, simulations have been run with 1) the default ECOCLIMAP-SG landuse at 300-meter resolution, which considers urban areas as 10 different categories, derived from the WUDAPT Local Climate Zones Classification, and 2) the Geoclimate urban morphology at 100-meter resolution, derived from the Open Street Map (OSM) database (Bernard et al., 2022). The latter employs the Open Street Map database to estimate close-to-reality urban geometries, with the help of a random forest technique to estimate missing building heights in the dataset.

 

The comparison with 79  in-situ observations shows that all the simulations are able to currently represent urban air temperature trends for homogeneous areas, such as the Paris city center and compact homogeneous areas. 

On the other hand, heterogeneous and scattered urban areas temperatures are not well represented by both higher-resolution simulations and the category-based ECOCLIMAP-SG landuse.On the contrary, the OSM-based landuse is sensible to city heterogeneity and horizontal variability.

 Considering the 100-m simulations, it is clear that category-based land uses are not suitable for very-high-resolution urban canopy layer simulations, since they cannot truly capture the neighborhood-scale variation within the same city.

For this reason, it is important, with increasing NWP resolution, to employ suitable landuse datasets, coherent with the employed horizontal resolution and applicable physical parameterizations.

How to cite: Zonato, A. and Theeuwes, N.: Very-high-resolution simulations with Harmonie-AROME of a heatwave case for the city of Pari with different landuse datasets., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18500, https://doi.org/10.5194/egusphere-egu24-18500, 2024.

EGU24-18976 | ECS | Posters on site | AS2.2

Integrating Airborne LiDAR Data into Urban Flow Models: A Focus on Buildings and Trees 

Dana Lüdemann, Niels Troldborg, Jan Pehrsson, and Ebba Dellwik

Airborne LiDARs can provide updated and highly accurate information of the 3D urban layer. This presentation focuses on transforming such information into boundary conditions for urban flow models.

When addressing buildings, we use a method called City3D [1], which outputs a watertight geometrical model at a specified level of detail (LoD).This resulting model is then utilized in the computational fluid dynamics (CFD) solver EllipSys [2]. We demonstrate how a novel implementation of the immersed boundary method (IBM) [3] simulates the wind flow and dispersion around the building. Additionally, we explore how different LoD
influence the simulation results.

The LiDAR data can also be used to model the drag force of trees. We demonstrate this process based on recent observations of a real tree. Finally, we discuss the relative importance of trees and buildings in an urban modelling context, highlighting the significance of including more details in the 3D urban layer.

References
[1] Jin Huang, Jantien Stoter, Ravi Peters, and Liangliang Nan. City3d: Large-scale building reconstruction from airborne lidar point clouds. Remote Sensing, 14(9), 2022.
[2] Jess A. Michelsen. Basis3D - a Platform for Development of Multiblock PDE Solvers: - release, volume AFM 92-05. Technical University of Denmark, 1992.
[3] Niels Troldborg, Niels N. Sørensen, and Frederik Zahle. Immersed boundary method for the incompressible reynolds averaged navier–stokes equations. Computers Fluids, 237:105340, 2022.

How to cite: Lüdemann, D., Troldborg, N., Pehrsson, J., and Dellwik, E.: Integrating Airborne LiDAR Data into Urban Flow Models: A Focus on Buildings and Trees, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18976, https://doi.org/10.5194/egusphere-egu24-18976, 2024.

EGU24-19930 | Posters on site | AS2.2

Modelling the urban heat island in Birmingham, UK at the neighbourhood scale  

Jian Zhong, Yanzhi Lu, Jenny Stocker, Victoria Hamilton, and Kate Johnson

Cities have higher peak temperatures compared to surrounding rural areas. The urban-rural surface air temperature difference is known as the urban heat island (UHI). As extreme heat exposure can lead to adverse health effects, information on UHI characteristics of cities is important for future urban climate planning strategies. This study applied the ADMS-Urban Temperature and Humidity model to investigate the key processes driving the UHI in Birmingham, UK, at the neighbourhood scale. This model was configured with a range of input datasets (such as meteorological data, landuse data, building data, anthropogenic heat sources etc) and run on the University of Birmingham’s BlueBEAR HPC. This urban climate modelling was evaluated against the temperature measurement datasets from UK Met Office and Weather Underground. The spatiotemporal variations of surface air temperature in Birmingham, UK were captured by this model. This modelling study can be further applied to explore the impacts of local urban head island mitigation strategies.

How to cite: Zhong, J., Lu, Y., Stocker, J., Hamilton, V., and Johnson, K.: Modelling the urban heat island in Birmingham, UK at the neighbourhood scale , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19930, https://doi.org/10.5194/egusphere-egu24-19930, 2024.

EGU24-20040 | Posters on site | AS2.2

Dynamics and spatial distribution of air pollution over Minsk, Belarus as revealed by mesoscale and high-resolution urban WRF-Chem modelling 

Siarhei Barodka, Ilya Bruchkouski, Nikita Kasushkin, Tsimafei Schlender, Piotr Silkov, and Tatiana Tabalchuk

This study is devoted to simulation of the Urban Pollution Island (UPI) phenomena over the urban territory of Minsk, Belarus and its surrounding area. We aim at recreating the common features of the air pollution spatial distribution and its time evolution on diurnal, week-long and seasonal scales. For that purpose we utilize WRF-Chem modelling system in nested runs using BEP/BEM urban parametrization schemes for the innermost high-resolution domains (500 m, 300 m, 100 m grid step). We employ two different approaches to urban morphology representation in the model (the Local Climate Zones methodology and direct representation of some of the urban parameters on the given model grid) and use ML-processed Open Street Maps (OSM) vector data and available remote sensing data to represent land use / land cover, buildings and streets parameters for Minsk urban territory and the surrounding area. A series of model runs is performed for time periods with various cases of meteorological conditions in different seasons of recent years. Anthropogenic emissions are specified for the Minsk area as several point sources (representing industrial emissions) and distributed sources over a network of main street and roads (representing vehicle emissions). By proceeding from national statistical data with estimates of main sources of atmospheric pollution in Belarus over the recent years, we formulate hypothetical distributions of emissions intensity over the specified sources and its temporal dynamics with diurnal and weekly cycles. Simulation results obtained with different configurations of the model, different weather conditions and different emission scenarios are compared to available observations: satellite remote sensing data, ground-based observations of air quality and meteorological parameters, vertical profiles of atmospheric pollution and meteorological parameters retrieved from MAX-DOAS and sodar observations.

How to cite: Barodka, S., Bruchkouski, I., Kasushkin, N., Schlender, T., Silkov, P., and Tabalchuk, T.: Dynamics and spatial distribution of air pollution over Minsk, Belarus as revealed by mesoscale and high-resolution urban WRF-Chem modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20040, https://doi.org/10.5194/egusphere-egu24-20040, 2024.

EGU24-499 | Posters on site | HS8.2.10

Simulating the Hydro-Geo-Chemical Processes during Submarine Groundwater Discharge by TOUGHREACT 

Tao Wang, Chenming Zhang, Ling Li, and Yajuan Yin

More than 60% of the global population lives in coastal areas, especially within 100 km from the coastlines, relying mostly on shallow groundwater resources. Seawater intrusion and submarine groundwater discharge (SGD) occur in the coastal aquifer systems, threatening these critical freshwater resources. Salinity seawater and fresh groundwater complexly interact with each other via SGD and SI. The SGD drives the discharge of not only a large volume of freshwater, but also terrestrial geochemical substances into the ocean through a mixing zone between discharging freshwater and recirculating seawater. The flux of SGD may be even greater than that of surface water through rivers and estuaries. For example, the SGD was estimated to be ~40 % and 80 %~160 % of the river water discharging flux into the South Atlantic Bight and Atlantic Ocean, respectively, and as a major source of dissolved organic matter and nutrients to Arctic coastal waters and the Mediterranean Sea.

A few hydrological models, including MARUN, SEAWAT, SUTRA, and PHT3D, are commonly used for SGD studies. The recently developed TOUGHREACT is robust in simulating coupled hydrodynamic, thermodynamic, and geochemical processes. From TOUGH2 (Transport Of Unsaturated Groundwater and Heat, version 2), a multi-dimensional numerical model for simulating coupled transport of water, vapor, non- condensable gas, and heat in porous and fractured media. However, TOUGHREACT is rarely used for SGD analysis, despite it being a well-rounded model with wide applications. Additionally, relevant studies on the iron (Fe) precipitation during SGD have focused predominantly on its spatial distribution and the adsorption of dissolved species, and studies on the genesis and geochemical evolution are scarce.

Therefore, we developed a systematic method using TOUGHREACT to simulate the hydrological processes in STEs and benchmarked the estimations; and then we numerically explored the groundwater flow and salt transport dur SGD by considering the influencing factors of tidal amplitude, freshwater head, seawater diffusion coefficient, and beach slope ratio. Consequently, by employing TOUGHREACT simulation, we analyzed the formation and spatiotemporal distribution of the Fe precipitation in the shallow beach aquifer due to the mixing of freshwater and seawater, and identified the key influencing factors during SGD.

The results show that, freshwater-derived Fe2+ is oxidized by O2(aq) in seawater during SGD, then precipitates as Fe (hydr)oxides (Fe(OH)3) to form an Fe precipitation zone. Fe(OH)3 tends to accumulate in the freshwater side of the mixing zone, whereas Fe(OH)3 precipitation in the seaward side of the mixing zone is inhibited by locally high H+ concentrations. The Fe(OH)3 first precipitates in the shallow aquifer, then extends to deeper layers over time, which is attributed to the increase in the residence time with the depth of both freshwater and seawater. The spatial distribution, and particularly, the extent of the iron curtain are influenced by the water flux and the concentration ratio of O2(aq) to Fe2+. These results are beneficial for better understanding the formation and distribution of iron curtains, and shed light on enhancing the understanding of the hydrogeochemical processes in subterranean estuaries.

How to cite: Wang, T., Zhang, C., Li, L., and Yin, Y.: Simulating the Hydro-Geo-Chemical Processes during Submarine Groundwater Discharge by TOUGHREACT, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-499, https://doi.org/10.5194/egusphere-egu24-499, 2024.

EGU24-1319 | ECS | Orals | HS8.2.10

Identifying urban subsurface thermal and hydraulic processes from time-series groundwater temperature data 

Ashley Patton, Peter Cleall, and Mark Cuthbert

The subsurface Urban Heat Island effect has been proposed as a shallow geothermal energy resource, however, annual near-subsurface temperature variation may result in unexpected system performance. Understanding heat transport processes in the urban subsurface is key to managing and modelling city-scale thermal regimes for geothermal energy resource development. Existing studies have focussed on analysis of repeat temperature-depth profiles rather than long-term groundwater temperature time-series. We show here how time-series analysis can complement temperature-depth profiles and offer additional insights into the controls on subsurface thermal transport processes.

Annual variations in temperature time-series from 49 boreholes in the Cardiff Geo-observatory (UK), recorded between 2014-2018, fall into several distinct shape categories. We hypothesise these shapes are indicative of the dominance of particular flow and heat transport mechanisms such that sinusoidal profiles are associated with conduction-only settings, while ‘right-skewed’ profiles denote the influence of advection. Short-lived temperature events are observed on the cooling limbs of such profiles and are correlated with groundwater level rises, indicative of recharge events. These winter temperature drops have the effect of cooling groundwater faster in winter than it is warmed in summer. The short timescales of these events suggest recharge is localised and may be controlled by preferential flow paths within the superficial deposits overlying the aquifer. While these events do have an overall cooling effect on the seasonal temperature profile, groundwater temperatures following these events recover quickly to levels near what they were before the recharge event, suggestive of the presence of local thermal non-equilibrium with the gravel aquifer. More complex behaviours observed in boreholes located close to the city’s rivers indicate recharge responses coupled with the influence of stream-aquifer interactions. Thus, temperature time-series data have potential as a tool to identify subsurface hydraulic and thermal processes, with implications for geothermal exploration and the wider field of hydrogeology.

How to cite: Patton, A., Cleall, P., and Cuthbert, M.: Identifying urban subsurface thermal and hydraulic processes from time-series groundwater temperature data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1319, https://doi.org/10.5194/egusphere-egu24-1319, 2024.

EGU24-1879 | ECS | Orals | HS8.2.10

Does an anthropogenically induced subsurface temperature hotspot affect groundwater ecology? 

Maximilian Noethen, Julia Becher, Kathrin Menberg, Philipp Blum, Simon Schüppler, Erhard Metzler, and Peter Bayer

Worldwide shallow groundwater is increasingly exposed to anthropogenic impacts. The thermal state of this important resource is affected not only by global warming but also by various local structures that release heat into the subsurface. This additional heat can accumulate and lead to local hotspots or - mostly urban - areas of elevated groundwater temperatures. The consequences of this warming for groundwater quality and ecology are widely unknown. Groundwater ecosystems are embedded in a naturally relatively stable environment, where temperature changes can affect the highly specialized, cold-stenotherm invertebrate community and meso- to psychrophilic microorganisms. In this study, we examine whether and how a groundwater temperature hotspot impacts groundwater ecology. We identified such a thermal anomaly in Hockenheim, Germany, caused by a water park with heated swimming pools and basements. The thermal impact was monitored over the course of a year by temperature data loggers in nine wells – four upstream and downstream of the structure each and one inside the basement. The same wells were sampled for chemical and microbiological parameters, such as the microbial total cell count and the cellular ATP content, as well as groundwater fauna. We additionally tested three wells in a nearby forest to obtain reference values that are mostly unaffected by anthropogenic interference. The measurements were repeated every three months in order to account for seasonal variations. The preliminary results show a local heat plume and an increase in groundwater temperatures by up to 8 K. However, there is no significant deterioration in the ecological parameters. Regarding the fauna, which generally shows low abundance due to oxygen depletion in the study area, we observed only a minor decrease within the thermally affected zone. Finally, the outcome of this study will improve our understanding of the vulnerability of groundwater ecosystems in the context of subsurface warming.

How to cite: Noethen, M., Becher, J., Menberg, K., Blum, P., Schüppler, S., Metzler, E., and Bayer, P.: Does an anthropogenically induced subsurface temperature hotspot affect groundwater ecology?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1879, https://doi.org/10.5194/egusphere-egu24-1879, 2024.

Springs offer insight into the sources and mechanisms of groundwater recharge and can be used to characterize fluid migration during earthquakes. However, few reports provide sufficient annual hydrochemical and isotopic data to compare the variation characteristics and mechanisms with both atmospheric temperature and seismic effects. As such, it is critical to obtain time series observations of stable isptopes (δ2H, δ18O and δ13CDIC) to understand the complex interactions between hydrological processes, cycle, and relationship with earthquakes. In this study, we used continuous δ2H, δ18O, δ13CDIC, and major ion data from four springs over 1 year to understand the groundwater origin, recharge sources, circulation characteristics, and coupling relationships with atmospheric temperature and earthquakes. We found that (1) the four springs are likely recharged by deep circulation of meteoric water from Bogda Mountain in the east, as well as long-distance runoff recharge from the Turpan Basin to the south. (2) atmospheric temperatures above and below 0 °C can cause significant changes in ion concentrations and water circulation depth, resulting in the mixing of fresh and old water in the aquifer, it can cause changes in δ13CDIC but it doesn’t work in δ2H and δ18O. (3) Earthquakes of magnitude ≥ 4.8 within a 66 km epicentral distance can alter fault zone characteristics (e.g., permeability) and aggravate water–rock reactions, resulting in significant changes in δ2H, δ18O, and hydrochemical ion concentrations, accompanied by limited changes in δ13CDIC. (4) Hydrogen and oxygen isotopes are the most sensitive precursory seismic indicators. The results of this study offer a reference for the establishment of long-term hydrochemical and isotopic monitoring, with the potential for use in earthquake forecasting.

This work is financially supported by the Natural Science Foundation of China (Grant No. 42373067) and by the Science for Earthquake Resilience (grant number XH23048C).

How to cite: Zhou, Z., Ren, X., Zhong, J., and Feng, X.: Response Characteristics of Hydrogen, Oxygen, and Carbon Isotope Composition to Atmospheric Temperature and Seismic Activity in Spring Water Hydrogeochemistry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2499, https://doi.org/10.5194/egusphere-egu24-2499, 2024.

EGU24-4000 | Posters on site | HS8.2.10

The impact of our warming climate on global groundwater temperatures 

Susanne A. Benz, Dylan J. Irvine, Gabriel C. Rau, Peter Bayer, Kathrin Menberg, Philipp Blum, Rob C Jamieson, Christian Griebler, and Barret Kuryly

Groundwater, the largest reservoir of unfrozen freshwater on Earth, plays a crucial role in supporting life and ecosystems. Its thermal regimes influence various environmental processes, impacting groundwater-dependent ecosystems, geothermal potential, and groundwater quality. Despite its significance, little is known about how groundwater responds to surface warming across spatial and temporal scales. Here we present a comprehensive analysis of global groundwater temperature patterns, utilizing the latest CMIP6 scenarios.

In this study we developed the first global model of groundwater temperature patterns, combining analytical solutions to conductive heat transport with high-resolution maps of ground thermal diffusivity and geothermal gradient. This model, validated with over 8,000 groundwater temperature measurements, allows users to estimate present and future temperature depth profiles globally. Past trends show a median global groundwater temperature increase of 0.3 °C over the last two decades. When simulating projected groundwater temperatures globally, our model reveals an average warming of 2.2°C (SSP 245) to 3.8°C (SSP 585) between 2000 and 2100 at the depth of the water table. Regional variations are substantial due to climate change and water table depth variability, with mountainous regions exhibiting the lowest warming rates. These distinct regional variations emphasize important thermal controls and the need for localized analysis.

Our work sheds light on the importance of understanding groundwater warming patterns, identifying 'hot spots' that may pose risks to both ecosystems and human well-being. In this study we also offer a specific focus on Europe, providing averages to enhance regional relevance and address emerging challenges in groundwater quality and habitat preservation.

How to cite: Benz, S. A., Irvine, D. J., Rau, G. C., Bayer, P., Menberg, K., Blum, P., Jamieson, R. C., Griebler, C., and Kuryly, B.: The impact of our warming climate on global groundwater temperatures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4000, https://doi.org/10.5194/egusphere-egu24-4000, 2024.

EGU24-4575 | ECS | Orals | HS8.2.10

Offshore freshened groundwater identified in southern Sicily (Italy) by applying well logs petrophysical interpretation.  

Damiano Chiacchieri, Lorenzo Lipparini, Aaron Micallef, and Elizabeth Quiroga

The work focused on the Oligo-Miocene Ragusa Formation, a known regional shallow aquifer in the Hyblean Plateau in southern Sicily, made of medium to high porosity carbonates deposited in the ramp environment, also investigated in the adjacent offshore by deep well drilling.

The main objective was to investigate if and how this known shallow onshore aquifer extend in the coastal area and possibly offshore.

A detailed methodology was defined for the quantitative use of geophysical logs from about five deep Oil & Gas wells to characterize groundwater in the Ragusa Formation in terms of pressure, piezometry and salinity distribution, as it follows:

  • A first step was the digitization of the full suite of logs required for the application of petrophysical workflow for each well analysed, for a total of about 25 km of digitized logs, such as SP (Spontaneous Potential), GR (Gamma Ray), DT (Sonic log) and Resistivity logs.
  • At the same time a synthetic lithological log for each selected well was built, to support the understanding of lithological influence of electrical logs.
  • A customised petrophysical workflow to calculate porosity and salinity (concentration of salts in TDS) was applied, considering: lithotypes, BHT (borehole temperatures), porosity (derived to DT – sonic log), pore fluid resistivity.
  • A comparison of TDS results with salinity data from DST and composite logs was performed.
  • A detailed well correlation and comparison between onshore shallow water wells and deep Oil&Gas wells, both onshore and offshore, was carried out.

By applying this petrophysical approach, it was possible to identify and quantified key indications of the presence of fresh groundwater in the Ragusa Formation carbonates both onshore and offshore in southern Sicily (Italy). Indeed, has been demonstrated that the onshore outcropping aquifer appear likely connected with the deep offshore aquifer due to positive indications in the same geological formation 10 km offshore from the coastline.

How to cite: Chiacchieri, D., Lipparini, L., Micallef, A., and Quiroga, E.: Offshore freshened groundwater identified in southern Sicily (Italy) by applying well logs petrophysical interpretation. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4575, https://doi.org/10.5194/egusphere-egu24-4575, 2024.

EGU24-4855 | ECS | Orals | HS8.2.10

Hydrogeochemical Characteristics and Genetic Mechanisms of Geothermal Fields in the Xi'an Depression of the Weihe Basin 

Jian Liu, Zhanli Ren, Qiang Yu, Xinyun Yan, Kai Qi, Zhen Wang, Sasa Guo, Huaping Lan, Mingxing Jia, and Yanzhao Liu

The geothermal resources in sedimentary basins have high potential for development and utilization, and have become an important research topic worldwide(Olasolo et al.,2016; Pasvanoğlu and Çelik., 2019; Duan et al.,2022). This paper focuses on the genetic mechanism and evolution process of deep geothermal water were explored through the analysis of hydrogeochemical and isotope geochemical data, which can provide technical and theoretical support for the sustainable development of geothermal fields in the Weihe basin. The study indicates that: (1)the hydrochemical type of geothermal water of Dongda geothermal field are predominantly HCO3·SO4-Na type. Meanwhile, the hydrochemical type of geothermal water of the northern Xi'an Depression are mainly SO4·HCO3-Na and SO4·HCO3·Cl-Na types. The ionic fraction is primarily influenced by the dissolution of silicate and evaporite minerals, as well as alternating cation adsorption. (2) Geothermal water is primarily recharged by atmospheric precipitation originating from the Qinling Mountains. The recharge elevation ranges from 677.94 m to 1467.65 m. (3) The Dongda geothermal field has a thermal storage temperature ranging from 50.19℃ to 80.29℃, and a depth of thermal circulation ranging from 1126.32 m to 2129.62m. Meanwhile, the northern Xi'an depression has a thermal storage temperature ranging from 73.17℃ to 109.50℃, and a depth of thermal circulation ranging from 1892.41 m to 3103.22 m. (4) The δ18O of the geothermal water in the northern Xi'an depression is more significantly shifted to the right of the atmospheric precipitation line than that of the Dongda geothermal water, indicating a significant “oxygen drift”.(5) The Dongda geothermal reservoir in the southern Xi'an Depression mainly experiences heat transfer through convection, while the geothermal reservoir in the northern Xi'an depression experiences heat transfer through conduction.

References

[1]Duan, R., Li, P., Wang, L., He, X., & Zhang, L. (2022). Hydrochemical characteristics, hydrochemical processes and recharge sources of the geothermal systems in Lanzhou City, northwestern China. Urban Climate, 43, 101152.

[2]Olasolo, P., Juárez, M. C., Morales, M. P., & Liarte, I. A. (2016). Enhanced geothermal systems (EGS): A review. Renewable and Sustainable Energy Reviews, 56, 133-144.

[3]Pasvanoğlu, S., & Çelik, M. (2019). Hydrogeochemical characteristics and conceptual model of Çamlıdere low temperature geothermal prospect, northern Central Anatolia. Geothermics, 79, 82-104.

How to cite: Liu, J., Ren, Z., Yu, Q., Yan, X., Qi, K., Wang, Z., Guo, S., Lan, H., Jia, M., and Liu, Y.: Hydrogeochemical Characteristics and Genetic Mechanisms of Geothermal Fields in the Xi'an Depression of the Weihe Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4855, https://doi.org/10.5194/egusphere-egu24-4855, 2024.

EGU24-5269 | Orals | HS8.2.10

Exploring the Hidden Exchanges: Groundwater-Surface Water Interactions in a Critical Zone Observatory 

Julian Klaus, Günter Blöschl, Enrico Bonanno, Barbara Glaser, Laurent Gourdol, Christophe Hissler, Luisa Hopp, Laurent Pfister, and Keith Smettem

The exchange between groundwater (GW) and surface water (SW) plays a crucial role for streamflow generation and the biogeochemical cycles within landscapes. However, accurately observing and predicting this exchange remains challenging due to the spatial heterogeneity and temporally dynamic fluxes of groundwater within the stream corridor. This presentation offers new insights into the characteristics of GW-SW interactions and hydrological processes within the hillslope-riparian-stream continuum, employing a combined experimental and modeling approach. The research builds on a comprehensive, long-term dataset obtained through baseline monitoring in the Weierbach Experimental Catchment (WEC) in Luxembourg that is a 45-hectare forested catchment. In addition to baseline monitoring, our approach involved (i) a network of 43 wells and piezometers along a selected stream reach for continuous monitoring and tracer experiments, (ii) a network of 13 wells along the riparian-hillslope interface, and (iii) ground-based thermal infrared imagery to observe spatiotemporal dynamics of surface saturation along the stream corridor. An integrated surface-subsurface hydrologic model served as a hypothesis-testing tool to examine whether surface saturation is predominantly driven by groundwater inflow or precipitation and how the relevance of the processes – surface ponding from precipitation or subsurface exfiltration – change in space and time.

We coupled the hydrological model with a hydraulic mixing-cell approach that enabled deciphering the contributions from different water sources to SW. The well network and associated artificial tracer experiments provided valuable insights into the direction of GW-SW exchange, revealing directional variability at scales of a few meters. Additionally, wells at the riparian-hillslope interface demonstrated a strong non-linearity of GW contributions to SW, influenced by GW table fluctuations. The observed and simulated surface saturation aligned well, suggesting that GW exfiltration primarily controls surface saturation in the stream corridor. Furthermore, the mixing-cell simulations revealed that subsurface water exfiltration is the dominant source for riparian surface water and intermittent streamflow, with distinct differences between stream water and riparian surface saturation. Overall, the combination of experimental techniques, hydrologic modeling, and well networks clearly improved our understanding of GW-SW interactions and revealed previously hidden exchanges in the WEC.

How to cite: Klaus, J., Blöschl, G., Bonanno, E., Glaser, B., Gourdol, L., Hissler, C., Hopp, L., Pfister, L., and Smettem, K.: Exploring the Hidden Exchanges: Groundwater-Surface Water Interactions in a Critical Zone Observatory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5269, https://doi.org/10.5194/egusphere-egu24-5269, 2024.

The analysis of twenty geophysical well logs covering a shelf area of about 3,500 km2 in front of the Emilia-Romagna coast (Italy), has shown apparent resistivity (ρa) values consistent with important Offshore Freshened Groundwater (OFG) reserves stored in the first 450 m of the Middle-to-Upper Pleistocene succession, and extending seaward about 60 km from the modern shoreline. Four classes with different ρa intervals (i.e., different salinities) were identified. The first three (1, 2 and 3) classes are characterized by ρa ranges of 7-28 Ω m, 4-7 Ω m and 2-4 Ω m, respectively. These values are higher than seawater resistivity (< 2 Ω m - i.e., class 4) and, based on the OFG definition (i.e., “the water stored in the sub-seafloor with a total dissolved solid concentration below that of seawater”), they have been used for OFG identification. Class 1 ρa is coherent with fresh-to-brackish water content, whereas classes 2 and 3 have been interpreted as transitional to seawater.
The correlation of offshore wells (spontaneous potential and ρa profiles) with onshore data (stratigraphic and lithological) from water wells and additional geophysical well logs, led to the stratigraphic architecture reconstruction of the Plio-Pleistocene siliciclastic succession along onshore-offshore transects, up to 60 km-long, from the Apennine front to the Adriatic shelf. The uppermost (first 450 m) Middle to Upper Pleistocene interval displays a vertical alternation of high-permeability (amalgamated and laterally continuous gravel to sand bodies) and low-permeability (mud-dominated) strata made of fluvio-deltaic, coastal and shelfal deposits. The high-permeability bodies represent the offshore extension of the onshore aquifer systems, whereas the low-permeability units make the aquitards. Along the transects, different stratigraphic intervals characterized by the four ρa classes have been identified. The highest ρa values (class 1) have been documented in the first 300 m of the succession, despite its deposition mostly occurred in deltaic to marine (i.e., saline water) conditions. This interval wedges out seawards, with ρa progressively decreasing down to class 3 values at about 35 km from the coast. Similarly, ρa decreases vertically, between about 300 and 450 m depth. Such a vertical gradual decrease may suggest that locally aquitards do not completely prevent water exchange, and transitional classes 2 and 3 likely resulted from freshwater and seawater mixing through space and time. Below 450 m depth, ρa drops to < 2 Ω m (class 4), thus defining the lowermost limit of the OFG reserves.    
Onshore-offshore reconstructions additionally revealed how OFG aquifers are actively recharged in correspondence of the Apennine front, where the topographic gradient is higher and permeable units are subaerially exposed. Their extremely high degree of amalgamation even allows the topographically-driven recharge of the deeper (and marine) strata.
The relatively shallow depth (< 350 m) of the northern Adriatic aquifers and the presence of several and abandoned oil&gas platforms in the area, provide a good opportunity to further investigate these OFG reserves that are strategic for the densely populated Emilia-Romagna coastal plain.

How to cite: Campo, B. and Antonellini, M.: Offshore freshened groundwater reserves identification as revealed by geophysical and stratigraphic data: insights from the Northern Adriatic shelf (Italy) , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5599, https://doi.org/10.5194/egusphere-egu24-5599, 2024.

EGU24-7016 | Posters on site | HS8.2.10

Characterization of near-shore fresh water and seawater interactions-the scale issues drawn from the experimental and numerical approaches 

Chuen-Fa Ni, Thanh Quynh Duong, Chia-Yu Hsu, Nguyen Thai Vinh-Truong, and Yu-Huan Chang

Understanding the dynamics of water and mass interactions in the coastal area is essential to quantify the influences of near-shore land use on the coastal aquifers and water environment. The study aims to integrate innovative experiments and modeling techniques to assess the heat and water exchanges in the coastal aquifer of the Taoyuan Tableland in northwestern Taiwan. The site-specific hydraulic and heat tracer tests are conducted to obtain flow and heat transfer properties for the specific aquifer layers at the site. We then used the SEAWAT numerical model to quantify the freshwater and seawater interactions. The model calibration relies on the groundwater levels and quality obtained from monitoring wells installed perpendicular to the shoreline. The experimental results show that the active heat tracer tests could significantly improve the identification of aquifer layers along a well and allow for the estimations of high-resolution natural groundwater flux toward the sea. The estimated flow rate based on the heat tracer test is approximately 0.2 m/day per unit depth. The numerical model shows good agreement with the observed water levels in wells. In the study area, the location of the seawater/groundwater mixing interface is estimated at approximately 350m seaward from the shoreline, which suggests the submarine groundwater discharge zone for the site. The vertical profile model shows that the flow rate for the 100m depth aquifer varies from 51 to 60 m3/day per unit width, depending on the tidal variations and upstream groundwater levels. The results show a large flow rate discrepancy between experimental and numerical approaches, which the resolution scales of the approaches might induce in the calculations. The water levels obtained from the fully opened screen wells might mix the flow responses in different aquifer layers.

How to cite: Ni, C.-F., Duong, T. Q., Hsu, C.-Y., Vinh-Truong, N. T., and Chang, Y.-H.: Characterization of near-shore fresh water and seawater interactions-the scale issues drawn from the experimental and numerical approaches, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7016, https://doi.org/10.5194/egusphere-egu24-7016, 2024.

EGU24-7668 | ECS | Orals | HS8.2.10

Downhole passive fiber optics temperature monitoring for improved characterization of aquifer heterogeneities 

Davide Furlanetto, Matteo Camporese, Luca Schenato, Leonardo Costa, and Paolo Salandin

Unconfined shallow aquifers are particularly exposed to the risk of contamination. Especially when exploited for drinking water production, for which water quality is of particular concern, careful monitoring of the physical processes and detailed characterization of the subsurface properties are crucial. Furthermore, the possible presence of heterogeneities, such as intricate networks of hydraulically conductive paleo-channels that are often inherent in alluvial aquifers, can establish preferential pathways. Consequently, monitoring activities in these complex environments pose serious challenges and raise the demand for advanced techniques and innovative approaches. In this context, recent advances have been made possible by employing Fiber Optics Distributed Temperature Sensing (FO-DTS). This technology combines the use of heat as a natural tracer with a detailed spatiotemporal resolution and has proven informative in a wide variety of applications. In this study, we applied downhole passive FO-DTS to a cluster of piezometers in a highly heterogeneous phreatic gravelly aquifer. The aquifer is exploited for irrigation and drinking water supply, and exhibits both natural and pumping-induced groundwater temperature fluctuations. Vertical transient water temperature profiles were acquired over a 1-month experiment. Borehole-dependent and depth-related features of the temperature measurements were ascribed to possible spatial structures having different hydraulic conductivity. The collected data were used to invert the three-dimensional saturated hydraulic conductivity field of a physics-based numerical model that couples flow and heat transport. Even without active heating, FO-DTS has demonstrated its ability to provide valuable insights at an unprecedentedly high resolution.

How to cite: Furlanetto, D., Camporese, M., Schenato, L., Costa, L., and Salandin, P.: Downhole passive fiber optics temperature monitoring for improved characterization of aquifer heterogeneities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7668, https://doi.org/10.5194/egusphere-egu24-7668, 2024.

EGU24-9552 | ECS | Posters on site | HS8.2.10

Spatio-temporal distribution of subsurface urban heat islands – Insights from shallow groundwater temperature monitoring in Vienna 

Eva Kaminsky, Gregor Laaha, Cornelia Steiner, Eszter Nyéki, Constanze Englisch, Christian Griebler, and Christine Stumpp

In numerous cities worldwide, a rise in surface temperatures had been observed, contributing to the so-called "urban heat island effect". This effect leads to extended and hotter periods of warm weather within urban areas not only above but also below ground. The heat in the subsurface can be used for shallow geothermal energy, but it requires knowledge of spatial and temporal variations in groundwater temperature for efficient and environmentally friendly utilization of groundwater for heating and cooling. In the course of the 'Heat below the City' project, we have compiled spatial high-resolution data and developed groundwater temperature maps for the city of Vienna targeting the coldest and warmest annual conditions. Borehole temperature profiles were recorded in October 2021 and April 2022. This enabled the identification of distinct urban heat islands. Additionally, available long-term data (2001-2020) was used to conduct annual temperature trend analyses and extreme value assessments to evaluate temperature changes over time. In Vienna, an average annual temperature increase, considering all significant trends, of 0.9 ± 0.1 K/decade was observed for air, soil and shallow groundwater between 2001 and 2021. However, the increase is non-linear and, over the last decade, the change has accelerated with an increase of 1.4 ±0.2 K/decade (only significant trends taken into account). The current annual mean temperature is 14.1 °C (2021/ 2022) with individual warmer urban heat islands and locally heated locations of up to 30.6°C. Trends in extreme temperatures (represented by the lower/upper 10th percentile air, soil and groundwater temperature in quantile regression) generally show the strongest increase in the lower 10th percentile temperatures for all air and soil temperatures. But this varies site-specifically in shallow groundwater, where urban infrastructure and the interaction between surface and groundwater, in addition to climate change, influence groundwater warming. Potentially, those urban heat islands with increasing trends in groundwater temperatures have great potential for heat utilization, but should not be used for extraction of cold. These findings emphasize the importance of spatial and temporal high-resolution data and highlight the necessity for site-specific aquifer characterization for a sustainable use of shallow geothermal energy for heating and cooling.

How to cite: Kaminsky, E., Laaha, G., Steiner, C., Nyéki, E., Englisch, C., Griebler, C., and Stumpp, C.: Spatio-temporal distribution of subsurface urban heat islands – Insights from shallow groundwater temperature monitoring in Vienna, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9552, https://doi.org/10.5194/egusphere-egu24-9552, 2024.

EGU24-10761 | ECS | Orals | HS8.2.10

Conceptual 3D groundwater models of offshore freshened groundwater extraction and its economic viability assessment 

Daniel Zamrsky, Joep J.H. van Lith, and Rens van Beek

Offshore freshened groundwater reserves have been identified in numerous regions worldwide. These reserves were often deposited during past sea level lowstands and are therefore non-renewable and slowly salinized by infiltrating seawater. However, in some cases these offshore freshened groundwater reserves can be connected to inland groundwater systems and can be recharged by fresh groundwater inflow from the landward direction. It has recently been suggested that these offshore freshened groundwater reserves could provide an additional source of fresh (and brackish) water for coastal communities that often face increasing fresh water stress. The feasibility, both economic and physical, of offshore freshened groundwater extraction is investigated in this study. To assess this feasibility from a physical point of view we built a set of 3D semi-conceptual groundwater flow models using the imod-wq code which allows us to estimate the offshore groundwater salinity development over large time scales (i.e. one glacial-interglacial cycle). The result of these large time scale models can be interpreted as estimations of the current offshore groundwater salinity conditions and thus provide a better picture of the current presence and magnitude of the offshore freshened groundwater resources in the model domain. In the next modelling stress period we introduce a set of pumping wells into the offshore domain and simulate several offshore freshened groundwater extraction scenarios. In such way we can evaluate the time it takes for these offshore freshened groundwater reserves to be fully salinized and exhausted. Additionally, we can also assess any potential negative impacts on the groundwater system in the coastal hinterland such as decreasing groundwater levels and/or increased salinization.

In the second part of our study we evaluate the economic feasibility of the offshore freshened groundwater pumping and use as additional fresh water resource for coastal communities. Several coastal areas located in south and south-east Asia (e.g. Pearl River delta) were selected since this region is identified as a region with high possibility and magnitude of offshore freshened groundwater resources. The economic parameters that are taken into account as favourable for offshore freshened groundwater exploration are (i) the overall economic development (e.g. GDP, HDI), (ii) the presence of groundwater pumping and desalination plants inland meaning the technology is already present in the region and (iii) costs of fresh water and groundwater pumping and desalination infrastructure in the region. Our study is only the first step in assessing the feasibility of offshore freshened groundwater exploration and hopefully our approach will be improved and tested in other coastal regions around the world to evaluate the full potential of these still untapped fresh groundwater resources.

How to cite: Zamrsky, D., van Lith, J. J. H., and van Beek, R.: Conceptual 3D groundwater models of offshore freshened groundwater extraction and its economic viability assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10761, https://doi.org/10.5194/egusphere-egu24-10761, 2024.

The validation of hydrogeological distributed models in western african countries is limited by the quality and availability of point station data measured in-situ. Climate models, satellite and reanalysis data have been suggested to overcome this limit. Here, we assessed the quality of ERA5 reanalysis on water table depth (WTD), and soil water content (SWC) over the Benin basins at spatial scale and monthly time scale. The single-levels version with 0.25° x 0.25° resolution (ERA5) and the land surface version with 0.1° x 0.1° resolution (namely LAND) were compared with point station data using the correlation performance evaluators and the Mean Absolute Error (MAE). The results showed that ERA5 and LAND reanalysis present well the water planes of Benin (WTD =0m). Outside wetlands areas, both reanalyses slight overestimation the WTD (MAE of ERA5=4.73m vs. LAND=3.13m. The SWC between 0-7 cm; 7-28cm and 28-100cm presented on both reanalyses are well in line with observations for all stations and on a monthly scale (correlation sometimes > 0.85 for LAND and 0.83 for ERA5). We recommend the use of LAND for validation of hydrogeological distributed models in Benin. Correcting the variables of these reanalyses could improve their performance.

How to cite: Bodjrenou, R.: Assessment of water table depth and soil water content Estimates from ERA5 reanalysis in Benin (West Africa), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12160, https://doi.org/10.5194/egusphere-egu24-12160, 2024.

EGU24-12406 | ECS | Posters on site | HS8.2.10

Investigating Submarine Groundwater Transmissivity in Svalbard Fjord Sediments through the Analyses of Physical Properties and Chemical Composition 

Zaga Trisovic, Matthew O'Regan, Sophie ten Hietbrink, Beata Szymczycha, Arunima Sen, Aivo Lepland, Jochen Knies, and Wei-Li Hong

We investigate submarine groundwater transmissivity within Svalbard fjord sediments, where offshore freshened groundwater (OFG) was confirmed through analyses of dissolved chloride concentration and water isotope signatures (δ18O and δ2H). The analyses are comprised of physical, mechanical, and chemical attributes of three cores recovered from Tempelfjorden and Hornsund fjords. Multi-Sensor Core Logger (MSCL) analyses provide high-resolution physical characteristics of the sediment cores, including bulk density, p-wave velocity, magnetic susceptibility, and electrical resistivity. These are integrated with X-ray computed tomography (CT) images, acquired with a Geotek rotating X-ray CT system (RXCT), to identify sedimentary facies, which are used to investigate internal core structures. Discrete measurements of grain density and grain size are used to calculate sediment porosity and to estimate the permeability. Our results indicate a heterogeneous sediment matrix with frequent drop stones and ice-rafted debris interlayered with finer-grained materials. We hypothesize that the sediment matrix packaging and configuration is an important control for the sediment permeability and thus for freshened groundwater transmissivity in the sediments of these fjords. This work is not only relevant for characterizing groundwater transmissivity in Svalbard's fjords but also will contribute to ongoing geological modeling efforts. Our findings pave the way for hydrogeological simulations, enhancing our understanding of OFG occurrence, emplacement mechanisms, and OFG volumes over successive glacial cycles.

How to cite: Trisovic, Z., O'Regan, M., ten Hietbrink, S., Szymczycha, B., Sen, A., Lepland, A., Knies, J., and Hong, W.-L.: Investigating Submarine Groundwater Transmissivity in Svalbard Fjord Sediments through the Analyses of Physical Properties and Chemical Composition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12406, https://doi.org/10.5194/egusphere-egu24-12406, 2024.

EGU24-13147 | Posters on site | HS8.2.10

Assessing Surface Water and Groundwater Interactions Using Long-Term Hydrological and Time-Lapse Seismic Data in the Orgeval Critical Zone Observatory 

Agnès Rivière, Marine Dangeard, Ludovic Bodet, Ramon Sanchez Gonzalez, and Alexandrine Gesret

Quantifying the water and heat fluxes at the interface between surface water (SW) and groundwater (GW) is a key issue for hydrogeologists to consider for safe yield and good water quality. However, such quantification with field measurements is not straightforward because the SW-GW changes depend on the boundary conditions and the spatial description of the hydrofacies, which aren't well known and are usually guessed by calibrating models using standard data like hydraulic heads and river discharge. We provide a methodology to build stronger constraints to the numerical simulation and the hydrodynamic and thermal parameter calibration, both in space and time, by using a multi-method approach. Our method, applied to the Orgeval Critical Zone Observatory (France), estimates both water flow and heat fluxes through the SW-GW interface using long-term hydrological data, time-lapse seismic data, and modeling tools. We show how a thorough interpretation of high-resolution geophysical images, combined with geotechnical data, provides a detailed distribution of hydrofacies, valuable prior information about the associated hydrodynamic property distribution. The temporal dynamic of the WT table can be captured with high-resolution time-lapse seismic acquisitions. Each seismic snapshot is then thoroughly inverted to image spatial WT variations. The long-term hydrogeological data (such as hydraulic head and temperature) and this prior geophysical information are then used to set the parameters for the hydrogeological modeling domain. The use of the WT geometry and temperature data improves the estimation of transient stream-aquifer exchanges.

How to cite: Rivière, A., Dangeard, M., Bodet, L., Sanchez Gonzalez, R., and Gesret, A.: Assessing Surface Water and Groundwater Interactions Using Long-Term Hydrological and Time-Lapse Seismic Data in the Orgeval Critical Zone Observatory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13147, https://doi.org/10.5194/egusphere-egu24-13147, 2024.

EGU24-13973 | ECS | Orals | HS8.2.10

Turn up the heat to locate and quantify groundwater flow in fractured rock aquifers in coastal zones of the tropical island of Curaçao 

Titus Kruijssen, Mike Wit, Sandra Akkermans, Joshua Leusink, Boris van Breukelen, Martine van der Ploeg, and Victor Bense

Dual porosity flow is an important mechanism for groundwater transport in fractured rock aquifers. However, quantification and characterization of fracture flow systems remains challenging, as it often involves complex procedures such as the injection of tracers. In this study we conducted single-well pumping tests in 11 uncased wells in a coastal fractured rock aquifer while monitoring in-well salinity and temperature gradients through downhole casts using a Conductivity-Temperature-Depth (CTD) logger. In this way, we aimed to observe how naturally occurring salinity gradients in the well become disturbed by induced groundwater flow to the well, and if these gradients may serve as natural tracers for fracture flow. Since natural temperature gradients in the wells are minimal, we applied point electrical heating at the bottom of the well to create a plume of slightly warmer water to migrate up the wellbore during pumping from the top. During the pumping tests in this set-up, repeated CTD casts suggest that groundwater flow to these wells is strongly focused along narrow zones and is occurring at various rates over a range of salinities and temperatures. Hence, the observed patterns in both salinity and temperature presumably reflect the presence of fracture zones, which could indeed be confirmed by downhole camera observations for some wells. Further data analysis resulted in detailed hydrogeological characterization of the 11 wells, comprising an assessment of the fracture density and hydraulic conductivity of the aquifers, as well as the origin of the inflowing water being meteoric mostly fresh water or deeper saline groundwater.

How to cite: Kruijssen, T., Wit, M., Akkermans, S., Leusink, J., van Breukelen, B., van der Ploeg, M., and Bense, V.: Turn up the heat to locate and quantify groundwater flow in fractured rock aquifers in coastal zones of the tropical island of Curaçao, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13973, https://doi.org/10.5194/egusphere-egu24-13973, 2024.

Geothermal heat production and aquifer thermal energy storage have significant potential to contribute to the energy transition. However, due to higher temperature inside the wells used, it is known that this leads to heat loss through conduction to the surrounding cooler, shallower groundwater systems. Therefore it is important to be able to anticipates such impacts to allow effective monitoring and prevention or mitigation measures when needed. However the thermal impact on groundwater systems is expected to strongly depend on local conditions. Therefore, this study focused on the impact of operational conditions (e.g. effective well temperatures and intermittency) and aquifer conditions (e.g. permeabilities and heterogeneity) on the resulting heat transport processes into the aquifer by conduction and density driven flow. To evaluate the degree and variation of impact that may occur under field conditions, the heat loss to a shallow groundwater system was simulated using a 2D axisymmetric numerical MODFLOW 6 model for a wide range of conditions considering both the impact of conduction and density-driven flow. The results of this study indicate that the total thermal impact and its distribution (up to >10 m from the hot well in 10 years) in shallow groundwater systems is strongly impacted by the induced density driven flow in the relatively permeable layers of the groundwater system. Conduction is dominant in transfer of heat from the hot well in the low permeability confining layers and for mitigating temperature differences in the groundwater system induced by buoyancy flow. Overall, this study highlights the importance of considering local conditions in assessing thermal impact by heat losses from hot well casings, to allow distinguishing these thermal impacts from those induced by leakage and to allow efficient thermal groundwater impact monitoring.

How to cite: de Vries, E. and Hartog, N.: Thermal impact on shallow groundwater systems by heat loss from hot wells: the impact of operational conditions and subsurface heterogeneity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15116, https://doi.org/10.5194/egusphere-egu24-15116, 2024.

The presented study focuses on quantifying the impact of the anthropogenic heat input from residential buildings on the subsurface temperature regime, employing an innovative approach that combines building physics simulations with heat and groundwater flow modelling. To enhance the applicability of the approach, sensitivity analyses of various parameters that govern the heat transfer from the investigated buildings are performed. The investigated parameters took hydrogeological and meteorological conditions, building properties (including different insulation standards and building types) as well as petrophysical rock properties into account.

The findings contribute to a comprehensive understanding of the subsurface temperature regimes within densely settled areas, which is particular significant for the impact assessment of shallow geothermal applications. Results of the study show that neglecting anthropogenic heat input may lead to an underestimation of the effects of shallow geothermal applications on the underground temperatures.

How to cite: Hastreiter, N. and Vienken, T.: Anthropogenic heat input into the subsurface: Influencing factors and its importance during shallow geothermal impact assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16623, https://doi.org/10.5194/egusphere-egu24-16623, 2024.

EGU24-17299 | ECS | Orals | HS8.2.10

Groundwater Level Assessment using Data logger and Manual monitoring in developing Country, southwestern Ethiopia 

Adisu Befekadu Kebede, Fekadu Fufa Feyessa, Thomas Hermans, and Kristine Walraevens

Groundwater monitoring is fundamental, especially for areas where there is a high dependency on groundwater use. Groundwater level (GWL) monitoring is poorly known in Ethiopia. The study focused on evaluating groundwater levels and their relation to precipitation in Ethiopia's Gilgel Gibe and Dhidhessa catchment areas. Groundwater levels (GWL), spring discharges, and rainfall data were collected from various points over the 2022/2023 hydrological year.  Rainfall varied across the region, increasing from April to September and decreasing from plateaus to lowlands with a value between 1539 mm to 1973mm annually. Groundwater levels showed significant spatial and temporal variation, influenced by precipitation and local topography.  Maximum water level varies between 17.6 and 5.75 m in the northwest, 11.6 and 6.2 m in the central part, 11.5 and 3.2 m in the east, 13.1and 4.2 m in the south. Minimum water level varies between 13.2 and 3.8 m in the northwest, 5.8 and 2.7 m in the central, 3.5 and 1.1 m in the east and 7 and 3. 6 m in the south of the study area. Groundwater level fluctuation in the automatically monitored well was 1.55m in the deep well and 3.99m in the shallow well. The spatial drop of the water table in the northwest and south is due to a hydraulic gradient to lowlands and depressions, and evapotranspiration from dense forest coverage. In the central and eastern study area, GWL is shallow and intermediate based on the positions of monitoring wells. Some wells are fully saturated during the rainy season between August and September. Shallow wells reacted swiftly to rainfall, but their levels declined in the dry season. Some wells in high elevation areas experienced minimal fluctuations due to their perched aquifer positions. Groundwater drawdown from usage in dug wells quickly recovered, suggesting potential for small-scale agricultural use. Long-term monitoring and increased data logging are recommended for future studies.

How to cite: Kebede, A. B., Feyessa, F. F., Hermans, T., and Walraevens, K.: Groundwater Level Assessment using Data logger and Manual monitoring in developing Country, southwestern Ethiopia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17299, https://doi.org/10.5194/egusphere-egu24-17299, 2024.

EGU24-17913 | Posters on site | HS8.2.10

Exploring historical anthropogenic influences on groundwater in the alluvial plain of the Upper Seine River 

Anne Jost, Gurpreet Dass, Fanny Picourlat, Shuaitao Wang, Laurence Lestel, David Eschbach, Nicolas Flipo, and Agnès Ducharne

Human activities have significantly influenced the hydrological functioning of wetlands since they were first settled, often with the aim of reducing their perceived inconvenient wetness. Reconstructing these historical developments and understanding their impacts on hydrosystems is essential to inform strategies for the sustainable management and conservation of these vital resources. We take the example of the upper Seine valley upstream of Paris, within the vast Bassée floodplain, to illustrate and quantify how the many artificial changes it has undergone over the centuries may have had a reciprocal effect on groundwater resources. We have identified three main types of land development, ranging from hydraulic works to direct groundwater abstraction, including land use changes associated with the extraction of alluvial sands and gravels that give rise to the gravel pit lakes that are particularly prominent in the study area. Our approach is based on a detailed cartographic reconstruction of each of these influences, feeding into a hydrogeological model of the plain. We outline the main principles behind its conception and then quantify the relative impacts of anthropogenic pressures on the aquifer system budget and water table depth.

How to cite: Jost, A., Dass, G., Picourlat, F., Wang, S., Lestel, L., Eschbach, D., Flipo, N., and Ducharne, A.: Exploring historical anthropogenic influences on groundwater in the alluvial plain of the Upper Seine River, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17913, https://doi.org/10.5194/egusphere-egu24-17913, 2024.

EGU24-19115 | ECS | Orals | HS8.2.10

Passive characterization of aquifer permeability and shear modulus and their evolution following earthquakes using tidal signals 

Augustin Thomas, Jerome Fortin, Benoit Vittecoq, and Sophie Violette

Tidal analysis of borehole pressure has become in the recent years’ literature an essential method to follow the evolution of the hydraulic conductivity of an aquifer over time. Most traditional methods (mainly pumping or slug tests) only produce a small number of observations, and come at a greater cost. However, groundwater level tidal analysis only requires monitoring data at a sampling rate of 1 hour, data which is extensively available. These solutions are applicable provided aquifers respond to at least one tidal phenomenon among oceanic, earth or atmospheric tides.

Martinique Island, in the Lesser Antilles, is a very interesting field to study these techniques, since 16 years of piezometric level data have been recorded on this volcanic island in a monitoring network of 29 boreholes. Here we focus our study on a closely monitored study site in the Galion plain, with three boreholes, a seismometer and past conducted pumping tests and seismic surveys. We compute amplitude and phase response of aquifers to atmospheric and earth tides. Then, the response of the semi-confined aquifers to different loading sources at the tidal frequencies (between 1 and 2 cycles per day) is modelled. A careful inversion is done to obtain the characteristics of the aquifer, including aquifer transmissivity and shear modulus.

Finally, we analyse the evolutions of these inverted parameters and decipher their reversible and irreversible changes. Between earthquakes, we show the dominant effect of effective stress to control aquifer hydraulic conductivity. At the time of the earthquake, with the help of seismic stress numerical simulation, we show that seismic shear stresses are the most probable cause of aquifer properties changes both in permeability and shear modulus.

How to cite: Thomas, A., Fortin, J., Vittecoq, B., and Violette, S.: Passive characterization of aquifer permeability and shear modulus and their evolution following earthquakes using tidal signals, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19115, https://doi.org/10.5194/egusphere-egu24-19115, 2024.

Temperature-depth profiles in the central part of the Netherlands collected over the past 7 years in a large number of piezometers document a regional increase in groundwater temperatures to depths of upto ~100 meters. This rise is congruent to observed increases in air temperature, related to climatic change. For some locations the data collected recently can be compared to similar observations done in the 1970-80s. Our observations show that the magnitude and rate of increase in groundwater temperature strongly vary by location and across depth. In part these differences can be explained by contrasts in land-surface conditions, but our analysis demonstrates that varying groundwater flow conditions also play an important role in explaining the observed patterns. Moreover, we show that an analysis of the transience in the temperature-depth profile can yield quantitative estimate of groundwater flow rates and subsurface hydraulic properties when combined with observations of hydraulic head gradients. We conclude that the current rising trends in groundwater temperature should provide a significant opportunity for the hydrogeological community to quantitatively analyze groundwater flow systems worldwide.

How to cite: Bense, V. and Kurylyk, B.: Drifting groundwater temperatures in the Netherlands: opportunities for hydrogeological analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19219, https://doi.org/10.5194/egusphere-egu24-19219, 2024.

EGU24-19836 | ECS | Posters on site | HS8.2.10

Offshore freshened groundwater emplacement in an evolving siliciclastic margin (Canterbury Bight, New Zealand): A 3D modeling approach 

Ariel Thomas, Daniel Zamrsky, Kamaldeen Omosanya, Mark Person, Joshu Mountjoy, and Aaron Micallef

Offshore freshened groundwater (OFG) represents a globally distributed subsurface resource with potential applications in water management, oil recovery, and environmental studies. Despite growing interest, the understanding of OFG systems, including their geometry, distribution, and emplacement dynamics, remains limited. In this study, we address these gaps by employing a novel 3D geostatistical modeling approach, focusing on the Canterbury Bight, a passive siliciclastic margin with proven OFG resources. Our methodology integrates high-resolution 2D seismic lines and borehole data, allowing us to capture the geological heterogeneity of the passive margin. Unlike traditional static models, our 3D approach considers the evolving stratigraphic architecture over multiple sea-level cycles, offering a more comprehensive understanding of OFG systems. Key findings include the successful incorporation of isostatic shifts and decompaction into our model, resulting in OFG distributions closely resembling those observed in the Canterbury Bight. We emphasize the importance of infilled buried channels and paleo-topographic highs in promoting OFG emplacement, shedding light on distribution patterns not easily explained by current seafloor topography or hydraulic heads. Our study advances the field by demonstrating how a 3D consideration of continental margin evolution significantly influences numerical estimations and improves the characterization of OFG resources. These findings contribute to a better understanding of OFG systems and provide valuable insights for future research and resource management.

How to cite: Thomas, A., Zamrsky, D., Omosanya, K., Person, M., Mountjoy, J., and Micallef, A.: Offshore freshened groundwater emplacement in an evolving siliciclastic margin (Canterbury Bight, New Zealand): A 3D modeling approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19836, https://doi.org/10.5194/egusphere-egu24-19836, 2024.

The traditional territory of the Lù'àn Män Ku Dän (Kluane Lake People) is found along the Saint Elias Mountains in Yukon. It hosts the Burwash Landing community, home of the Kluane First Nation, which is one of eleven self-governing First Nations operating in tripartite with Yukon Government and Canada. Burwash Landing is primarily dependent on diesel for space heating and power generation. Cutting-edge technologies were deployed in the scope of geothermal resource assessment to evaluate the thermal state and properties of the subsurface. Active distributed temperature sensing was conducted with a composite heating and fiber-optic cable installed in the water column of two existing wells with the objective of quantifying the geothermal potential and groundwater flow along available wellbores. Heat injection tests were made in the 220 and 385 m deep wells located on the south and north side of the Denali fault, near a probable releasing bend that is favorable to permeability. Melting glacier water infiltrates in mountains and groundwater flows toward Kluane Lake, which is hypothesized to be a major groundwater discharge zone. The shallower well is at an altitude of 925 masl and intercepted 40 m of quaternary deposits before hitting fractured bedrock while the deeper well is at the valley bottom near the lake (altitude of 795 masl) and entirely drilled in quaternary deposits. Passive temperature monitoring was initially made and revealed a geothermal gradient of 34 ⁰C km-1 and 47 ⁰C km-1 in the shallow south side and deep north side wells. Heat was injected during active tests for 2 and 3 days and thermal recovery was monitored for 6 and 8 days, respectively. Temperature was measured every 25 cm at 4-minute intervals. The infinite line source equation and the superposition principle were used to analyze data and calculate a thermal conductivity profile. Nearly continuous ground thermal properties and temperature profiles were combined to assess the Earth natural heat flux, considering paleoclimate and topographic corrections. Analysis indicated a heat flux above 90 mW m‑2, thought to be favorable for geothermal resource development. Peclet number analysis was undertaken to infer horizontal groundwater flow in permeable horizons. Results are being used to develop a regional groundwater flow and heat transfer model to evaluate temperature at kilometer depth and assess the communities’ geothermal potential. This presentation will illustrate how active temperature sensing can be deployed to reduce geothermal exploration risks, acknowledging Kluane First Nation that allowed us to better understand groundwater flow in this magnificent territory.  

How to cite: Raymond, J., Chapman, F., Klepikova, M., Bour, O., and Soucy Laroche, R.: Active fiber-optic distributed temperature sensing to assess the geothermal potential and groundwater flow over the traditional territory of the Lù'àn Män Ku Dän, Yukon, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20169, https://doi.org/10.5194/egusphere-egu24-20169, 2024.

EGU24-20229 | Posters on site | HS8.2.10

Characterization of deep infiltrations in subsurface drained agricultural system 

Hocine Henine, Julien Tournebize, Cedric Chaumont, Arnaud Blanchouin, Agnès Rivière, and Rémi Clément

Subsurface drainage practice is widely used in agriculture to eliminate temporary winter waterlogging of hydromorphic soils. Soil surface saturation is mainly due to the presence of an underlying layer (~1m deep) with a high clay content, considered as semi-impermeable. Generally, deep infiltration under this layer has been neglected in many hydrological studies. However, considering the variations in the ground water table levels, the recharge is mainly due to the deep infiltration. Understanding the dynamic of this infiltration is very important both for the quantitative management of groundwater resources and for the protection of its quality. Indeed, this infiltration can transfer spreading products (fertilizers and pesticides) used in agriculture, mainly the water-soluble molecules.

To understand the dynamic of the deep infiltration, hydrological and geophysical monitoring using ERT (Electrical Resistivity Tomography) method was set up on the drained experimental plot of Boissy le Châtel (Orgeval Observatory, in France). The water balance at the scale of the experimental plot highlighted the contribution of the deep infiltration to the groundwater table rise at the beginning of fall season.

Time-lapse geophysical survey coupled with water content monitoring on a 1.5m vertical profile showed the movement of a rewetting front from the soil surface towards deep layers during this very short transition period, which follows a precipitation event. After this period, during the intense drainage season, the deep infiltration below the drains continues (in the order of 0.12 mm/day compared to 2mm/day for subsurface drained flow) despite the rise of the water table to the surface layer. However, it is difficult to monitor its pathway using the passive ERT method, less sensitive to electrical resistivity variations in the range of soil water content close to saturation.

How to cite: Henine, H., Tournebize, J., Chaumont, C., Blanchouin, A., Rivière, A., and Clément, R.: Characterization of deep infiltrations in subsurface drained agricultural system, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20229, https://doi.org/10.5194/egusphere-egu24-20229, 2024.

EGU24-21278 | ECS | Posters on site | HS8.2.10

 Using thermal tracer tests and numerical models to evaluate the layered flow characteristic in a coastal aquifer system  

An-Yi Hsu, Chuen-Fa Ni, Chia-Yu Hsu, and Yu-Huan Chang

 With the increasing economic development in coastal areas, the problem of coastal degradation has emerged. To facilitate subsequent planning of water resources management, it is essential to determine the coastal aquifer's dynamic exchange with ocean. In this research, our objective is to integrate innovative experiments and modeling techniques to assess the heat and water exchanges in the coastal aquifer of the Taoyuan Tableland in northwestern Taiwan. Specific hydraulic and heat tracer tests are conducted at this location to obtain the flow and heat transfer characteristics of the layered flow. In subsequent steps, we employed the MODFLOW and MT3DMS numerical model to simulate the influence of interactions between freshwater and seawater on the temperature field of the coastal aquifer. The calibration of the model is based on the groundwater levels and the temperature acquired from monitoring wells which installed near the coastline at the TAICOAST observation station. The experimental results show that the thermal responses from the active heat tracer test can match with the core sample and calculate the groundwater flux toward the sea. Significant thermal responses are observed vertically in the observation well near the heating well, ranging from the water level to a depth of 12 m, with BW08 being the observation well showing the maximum thermal response. The simulation of numerical model aligns well with the observed water levels and temperature in wells. The simulation provides a three dimensional depiction of the groundwater flow direction, which was used to calculate the velocity of groundwater flow and estimates thermal conductivity at this site. The results reveal the dynamic impacts of tidal variations on the coastal aquifer with high spatial resolution provides the valuable insights into understanding the groundwater discharge in the coastal aquifer system. 

How to cite: Hsu, A.-Y., Ni, C.-F., Hsu, C.-Y., and Chang, Y.-H.:  Using thermal tracer tests and numerical models to evaluate the layered flow characteristic in a coastal aquifer system , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21278, https://doi.org/10.5194/egusphere-egu24-21278, 2024.

Before extraction of offshore freshened groundwater (OFG) begins, ownership must first be determined in order to confirm the right to access, possess and distribute of the resource.  Since the geological formations sheltering OFG extend beyond the coastline, the UN Convention on the Law of Sea, which has been ratified by most countries in the world, will apply, and it provides that the nation having rights to the continental shelf where the OFG is located will have sovereign rights to the resource.  However, political boundaries do not often respect geologic formations, and some deposits of OFG will straddle national boundaries.  The Law of the Sea Convention is silent on transboundary resources, so policymakers must look to other legal principles that address governance of natural resources in order to develop a governance regime.  This presentation will summarize the applicable international law principles and will provide guidance on how transboundary OFG may be governed.

How to cite: Martin-Nagle, R.: Transboundary Offshore Freshened Groundwater: What Law Applies?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21423, https://doi.org/10.5194/egusphere-egu24-21423, 2024.

EGU24-216 | ECS | PICO | HS5.2.3 | Highlight

Assessment of Hydropower Generation and Green Hydrogen Production Potential in Jebba Dam, Nigeria, West Africa 

Emmanuel Olorunyomi Aremu, Agnidé Emmanuel Lawin, David Olukanni, Harrie-Jan Hendricks Franssen, and Nathalie Voisin

Hydropower can play a significant role in advancing the production of green hydrogen. However, hydro-climatic variability impacts hydropower production and thus the hydrogen potential. In this study, we developed novel analytics to understand how hydropower inter-annual variability translates to hydrogen production. We address this by; (i) analyzing Jebba dam hydro-climatic variables and associated hydropower generation (ii) translating the annual and quarterly hydropower production into hydrogen using five assumed scenarios; (iii) estimating the re-electrification potential and (iv) determining the quantity of petrol (or gasoline) that would be replaced and the amount of CO2 and CO that would be avoided. We find that hydropower energy generation has increased significantly at the station. The estimated annual and quarterly green hydrogen potentials indicated that the highest potentials were 59,111 tons and 18,744 tons and have a re-electrification potential of 1,182 GWh and 374 GWh, which can replace 0.224 million liters and 0.071 million liters of petrol (or gasoline) in the year 2021 and the fourth quarter of 2021–04, respectively. This would prevent 0.52 million kg of CO2, 0.92 thousand kg of CO in the year 2021, and 0.163 million kg of CO2, 0.293 thousand kg of CO emissions in the fourth quarter of 2021–04. The study concludes that the impact of hydro-climatic variation on hydropower generation affects green hydrogen production potential. Nevertheless, using a percentage of hydropower energy can present a unique opportunity to move the nation toward the production of green hydrogen energy as a long-storage solution for rural areas' re-electrification and to meet electricity demand when the hydropower dam’s water storage is low. Furthermore, the adoption of a green hydrogen energy solution can contribute to the nation's and global climate change mitigation efforts.

How to cite: Aremu, E. O., Lawin, A. E., Olukanni, D., Hendricks Franssen, H.-J., and Voisin, N.: Assessment of Hydropower Generation and Green Hydrogen Production Potential in Jebba Dam, Nigeria, West Africa, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-216, https://doi.org/10.5194/egusphere-egu24-216, 2024.

In comparison to traditional fossil fuels, hydropower has the potential to significantly reduce greenhouse gas emissions and play a crucial role in promoting a low-carbon energy structure transformation. However, the reliability and stability of the hydropower system in the warming future remain unclear. Here, we evaluate the impact of future climate change on hydropower production, regional electricity demand, and energy system supply-demand balance in the Yangtze River Basin (YRB), which is China's largest hydropower production base. We have utilized two indexes, i.e., Energy Production Drought (EPD) and Energy Supply Drought (ESD), to characterize the changes in the hydropower energy system. EPD refers to a series of days with low hydropower production, while ESD refers to a series of days with mismatched production/demand. We utilize 15 global climate models from CMIP6 to force the Conjunctive Surface-Subsurface Process version 2 (CSSPv2) land surface model with consideration of reservoir regulations, to estimate the generation capacity of 86 mainly hydropower plants in YRB. In addition, an empirical electricity demand model considering socio-economic and climate factors is adopted to evaluate the changes in electricity demand in the receiving areas of southern China. Under climate change, the projected hydropower generation in the YRB is expected to increase throughout the 21st century. However, the future electricity demand will also rise due to GDP growth. Climate change will alter the distribution of seasonal electricity demand, resulting in an increasing mismatch between electricity demand and hydropower supply. Therefore, hydropower EPD and ESD are also being investigated, and the study is crucial for understanding future changes in the electricity supply and demand balance, as well as mitigating the impact of global warming.

How to cite: Liu, X. and Yuan, X.: Future changes in hydropower energy system in the Yangtze River Basin under different warming levels, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-264, https://doi.org/10.5194/egusphere-egu24-264, 2024.

El Niño events pose a significant threat to water security in the Godavari river basin (GRB), leading to adverse impacts on water-energy nexus. To enhance long-term energy security, we developed an integrated framework combining the hydrological model, variable infiltration capacity (VIC) model, and geospatial tools to identify potential sites for run-of-river small hydropower (RoR-SHP) plants. The study utilized long-term (1951-2020) daily streamflow data, simulated with the VIC model for design discharge computation at 30%, 75%, and 90% flow dependability. The analysis revealed considerable potential for RoR-SHP development within the GRB, identifying 226 initial sites based on the head along the river, with a combined power and annual energy generation estimate of 92 MW and 0.4 TWh/yr, respectively, at 90% flow dependability. After meticulous screening, 11 potential sites based on the head and the power potential were identified. The detailed analysis during El Niño years demonstrated a decline of approximately 46%, 38%, and 18% in total annual energy at 30%, 75%, and 90% flow dependability, respectively, compared to normal years. Consequently, we proposed nine potential sites based on the head, power potential, and viability under El Niño for RoR-SHP development, capable of maintaining the firm power even during El Niño years. Our findings highlighted the increased risk of power shortages in the GRB during El Niño years, emphasizing the imperative need for implementing water-energy nexus strategies to cope with the risks associated with El Niño events.

How to cite: Kasiviswanathan, K. S. and Thakur, C.: An Integrated Hydrological Modeling Framework for Enhancing Water-Energy Nexus during El Niño Events in the Godavari River Basin, India , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1567, https://doi.org/10.5194/egusphere-egu24-1567, 2024.

EGU24-2281 | ECS | PICO | HS5.2.3

Assessing Carbon Emissions from Reservoirs in China: Insights from the G-res Model and Implications for Hydropower Planning 

Zilin Wang, Meili Feng, Faith Chan, and Matthew Johnson

Reservoirs are an important source of emissions of carbon-based greenhouse gases (GHGs). China has about tens of thousands of reservoirs, about half of the world's total reservoirs, and therefore needs a more accurate estimate of current carbon emissions from reservoirs. This study utilizes the Greenhouse Gas from Reservoirs (G-res) model to assess CO2 and CH4 fluxes for 1479 reservoirs in China. The findings reveal that Chinese reservoirs contribute 0.156 Tg CO2 eq yr−1 in CO2 emissions and 6.657 Tg CO2 eq yr−1 in CH4 emissions. Across the nine main river basins in China, negative CO2 diffusive emissions from reservoirs are observed where large size reservoirs were attributed specifically the Northern inland and Xinjiang basin, southwest international basin, Yangtze basin, and Pearl basin. Similarly, CH4 fluxes through degassing and ebullition diffusion pathways exhibit a decreasing trend from small to large in the categorisation according to storage capacity. The findings in this study investigated significant GHG emissions from reservoirs in China, but also highlighted the different circumstances under which certain large reservoirs have the potential to act as CO2 carbon sinks. In order to reduce greenhouse gas emissions, it is crucial to strategically review hydropower planning, in which the cumulative effects of small reservoirs and the large impacts of large reservoirs should be considered.

How to cite: Wang, Z., Feng, M., Chan, F., and Johnson, M.: Assessing Carbon Emissions from Reservoirs in China: Insights from the G-res Model and Implications for Hydropower Planning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2281, https://doi.org/10.5194/egusphere-egu24-2281, 2024.

EGU24-3867 | ECS | PICO | HS5.2.3

Automatic estimation of reservoir inflows of Alpine hydropower cascade systems using level and outflow data 

Nicola Crippa, Pietro Marzaroli, and Marco Tarabini

Alpine hydropower reservoirs play a crucial role in the energy system as a source of renewable energy and energy storage, as well as in water management mitigating the impacts of extreme events and augmenting freshwater availability. The effective operation of hydropower reservoirs requires knowledge of the expected inflows, and the inflows prediction methods usually require the historical series of observed inflows. The reservoir inflow is often estimated because it is hardly measurable due to its spatial distribution along the reservoir sides. However, traditional methods such as the Simple Water Balance for estimating inflows can yield fluctuating and potentially negative results due to errors in water level measurement and stage-storage relationships. This study focuses on the estimation of inflow to ten reservoirs belonging to three different hydropower cascade systems situated in the Italian Alps. Two new methodologies to estimate reservoir inflow are proposed. The first (Optimized Inflow Estimation from Water Balance, OIEWB) consists of an optimization-based method and extends a known literature optimization technique to cascade reservoirs. In particular, the OIEWB method estimates the inflows to cascade reservoirs solving a bi-objective optimization problem aiming to minimize both the differences between consecutive inflow and the differences between observed and estimated water levels. It also includes an automatic calibration of the weight of the objectives according to the physical characteristics of each reservoir, avoiding any a priori calibration. The second (Filtered Inflow Estimation from Water Balance, FIEWB) consists of a low-pass filter shaped as a piecewise linear function whose slope is defined, again, by the physical characteristics of each reservoir. The low-pass filter is applied to the SWB cascade reservoir inflow to remove the high-frequency fluctuations that can be generated by measurement and estimation errors. The proposed procedures have been compared with the traditionally used ones in terms of Inflow Variability (the difference between inflow at two consecutive time steps) and Storage Error (the difference between the estimated reservoir storage and the observed one). Results show that both the OIEWB and FIEWB methods generate smoother inflows compared to the SWB, reducing the average Inflow Variability standard deviation, of 86.6% and 79.3%, respectively. However, the FIEWB does not guarantee the positivity of the inflows and can lead to large Storage Errors. The OIEWB method has been found to be more flexible and automatically adaptable to reservoirs with a wide range of physical characteristics. Nevertheless, a relationship between the OIEWB and the FIEWB has emerged. This relationship can be used to design new low-pass filters that can emulate the behavior of the OIEWB, combining the flexibility of the latter with the simplicity of the FIEWB. By contributing to provide more accurate and reliable inflow predictions, the proposed methodologies reveal their utility in optimizing cascade reservoir operation, thereby facilitating better decision-making.

How to cite: Crippa, N., Marzaroli, P., and Tarabini, M.: Automatic estimation of reservoir inflows of Alpine hydropower cascade systems using level and outflow data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3867, https://doi.org/10.5194/egusphere-egu24-3867, 2024.

EGU24-6751 | ECS | PICO | HS5.2.3

Hydropeaking Mitigation with Re-Regulation Reservoirs 

Ali Mchayk, Ali Torabi Haghighi, Hannu Marttila, and Björn Klöve

The role of hydropower as a renewable and balancing power source is expected to significantly increase in a scenario of Net Zero Emissions by 2050. As a common phenomenon in hydropower plants, hydropeaking will become more prominent, resulting in additional stresses on the ecological status of rivers. Here we propose a novel engineering approach to operate auxiliary reservoirs, termed re-regulation reservoirs to address the challenges posed by hydropeaking on river flow regimes. A re-regulation reservoir aims at smoothing flow fluctuations caused by hydropeaking by diverting and retaining parts of high flows and returning them back to river corridors during low flows. The regulatory performance of re-regulation reservoirs is a function of its geometry and volume availability, and It is defined and optimized by restricting the thresholds of various flow components.

In this study we developed a methodology and an open-access algorithm to operate re-regulation reservoirs using data from Kemijoki River, one of the most regulated rivers in Finland. The theoretical foundation of the algorithm was based on two main objectives, with the first aiming to reduce the hourly peak flow and increase the minimum hourly flow induced by hydropeaking. While the second objective aims to reduce the up- and down- ramping rates to increase the timespan of water level changes in the river’s corridor. Thus, the algorithm establishes a hierarchy of conditions to restrict peak flow, minimum flow, up-ramping rates, and down-ramping rates. However, as the ideal flow conditions for various ecosystem services may be different, a range of thresholds was utilized in each of the algorithm’s conditions resulting in thirty-five possible hydropeaking mitigation scenarios.

In all of the thirty-five tested scenarios, the re-regulation reservoir limits peak and minimum hourly flows and ramp rates according to thresholds defined by the algorithm. The results demonstrated that in most cases the required volume of the re-regulation reservoir increased as the thresholds for flow components became more stringent. However, for some scenarios this trend was not observed, indicating that matching the peak and minimum hourly flow with the ramping rates thresholds is required to achieve optimal re-regulation reservoir design. Nonetheless, our calculations show clear theoretical possibilities for regulating hydropeaking with re-regulation reservoirs.

Compared to other mitigation measures, such as the installation of downstream flow control devices or modifying the operation of hydropower facilities, re-regulation reservoirs offer greater flexibility and adaptability to changing environmental conditions, power, and water demand without increasing the operational cost of power systems.

How to cite: Mchayk, A., Torabi Haghighi, A., Marttila, H., and Klöve, B.: Hydropeaking Mitigation with Re-Regulation Reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6751, https://doi.org/10.5194/egusphere-egu24-6751, 2024.

EGU24-7354 | PICO | HS5.2.3 | Highlight

Reconsidering hydropower in the African energy transition 

Matteo Giuliani, Andrea Castelletti, Angelo Carlino, and Wyatt Arnold

African nations are striving to meet increasing energy demands driven by population growth and improving living standards. To reduce emissions, many national capacity expansion plans are attempting to use low-carbon electricity sources and exploit the untapped continental hydropower potential with 300 new hydropower projects planned for a total of around 100 GW of new installed capacity. However, climate, socio-economic, and technological changes are making these investments in new dams more risky and less economically efficient.

In this talk, we discuss the role of hydropower projects across different power capacity expansion pathways in Africa. Our multi-scale analysis is built on an integrated modeling framework that combines an Integrated Assessment Model (GCAM), an energy system planning model (OSeMOSYS-TEMBA), a power system model (PowNet), and a strategic river basin-scale reservoir system model. This framework allows the simulation of different future scenarios that harmonize global climate policies, land-use change, climate impacts on water availability, final energy demands, and multipurpose reservoir operations.

Our results show that, depending on the scenario considered, between 32 and 60% of the proposed hydropower capacity is not cost-optimal. Moreover, our analysis suggests that hardly any new hydropower will be built after 2030, meaning that its role in terms of installed capacity and generation will gradually decrease in favor of solar and wind power. Besides, floating photovoltaics might also represent a low-impact alternative to hydroelectric dams, producing 20-100% of the electricity from planned hydroelectric dams depending on the scale of deployment of this new technology on existing hydroelectric infrastructure at the African power pool scale. Lastly, we show how policy fragmentation between developed and developing countries in their approach to land use change emissions can have negative side effects on local water demands, producing favorable conditions for the realization of extensive agricultural projects in Africa that increase local irrigation demands and constrain the availability of water resources for hydropower production.

These findings show that strategic planning of water-energy systems is essential to navigate the complex landscape of hydropower development in Africa. By adopting a systemic approach, African nations can identify cost-efficient climate-resilient hydropower projects that will contribute in securing a sustainable and resilient energy future.

How to cite: Giuliani, M., Castelletti, A., Carlino, A., and Arnold, W.: Reconsidering hydropower in the African energy transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7354, https://doi.org/10.5194/egusphere-egu24-7354, 2024.

EGU24-8003 | ECS | PICO | HS5.2.3

A Life cycle assessment of energy harvesters in existing European water networks for distributed network monitoring 

Bethany Bronkema, David C. Finger, Bjarnhédinn Gudlaugsson, and Dogan Gezer

Recent developments in eastern Europe, increasing climate disasters and the continuous threat of volcanic eruptions have revealed the vulnerability of present energy and water supply systems. To enhance the resistance of existing water and energy infrastructure, holistic monitoring relies on decentralized energy production. Energy harvesters (EH) utilize kinetic energy in existing water pipelines to produce an electric current to power sensors and other components related to water infrastructure monitoring, replacing vulnerable and cost intensive diesel generators.  EHs could represent an ideal solution to provide reliable and continuous power to decentralized monitoring systems. To characterize and assess the environmental impacts of EH, a complete life cycle assessment (LCA) was conducted using GaBi software and the ecoinvent database, as well as data collected from various case studies. This LCA focuses on EH in existing water facilities and networks and includes manufacturing, transport, usage, and decommission stages for the EH. In modeling this technology from cradle-to-grave, a more complete understanding of its environmental impacts can be obtained. Special focus in this LCA was given to the allocation of impacts to services provided by water networks, e.g., drinking water supply, heat supply and water purification. Preliminary results suggest that a scale up of these harvesters could bring their global warming potential – measured in g CO2, eq/kWh – down to a level that is competitive with conventional hydropower while having significantly less impacts on surrounding natural areas. Our results focus on the case study in Iceland, the district heating system in Reykjavik. The preliminary results suggest that most impacts stem from the production of the material needed for the harvester, with little coming from the operation phase. As discussed above, EHs could provide a solution to decentralized monitoring systems. One application being explored for these harvesters is to power sensors along the existing water facility network, thus adding not only to the reliability of power supply, but to the overall reliability of the water network and provided a cleaner source of power than traditional diesel generation. If considered as part of an allocation LCA, these emissions savings constitute an additional reduction in the harvesters’ impacts. Essentially, the results of this LCA suggest that EH in existing water systems represents a crucial element in the low-carbon energy transition. EH could increase resiliency and energy security, while tapping into already existing water supply networks, ideally without adverse effects on these systems. While our results focus on a case study in Iceland, we plan to apply the approach to drinking water supply systems in Ferlach, Austria and Izmir Turkey, water purification in Padova, Italy and natural currents in the lagoon of Venice, Italy. The ensemble of the results from all case studies could reveal the full potential of EH across Europe.

How to cite: Bronkema, B., Finger, D. C., Gudlaugsson, B., and Gezer, D.: A Life cycle assessment of energy harvesters in existing European water networks for distributed network monitoring, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8003, https://doi.org/10.5194/egusphere-egu24-8003, 2024.

EGU24-8551 | ECS | PICO | HS5.2.3

Global loss in global hydropower supply under droughts using a hybrid model 

Jignesh Shah, Jing Hu, Oreane Edelenbosch, and Michelle van Vliet

Hydropower is considered as an important source of renewable energy due to its flexibility and storage capabilities. However, hydropower faces significant challenges with climate change and especially the increasing risks of extreme weather events such as droughts.

In this study, we analysed the impact of historical droughts on hydropower at a global scale by developing a hybrid model that combines a physically based hydropower model with a machine learning model. This integrated approach enables us to capture important features affecting hydropower generation beyond water availability, considering the details of local specific conditions at hydropower plant sites while it can be applied across the globe. A new open-source global dataset is developed that contains key information of the hydropower plant characteristics and their reservoir attributes by merging various plant sources with a global reservoir database. The hybrid model is trained against observed monthly hydropower generation data at the power plant level. By employing this approach, we aim not only to enhance the realism of simulating hydropower output compared to the simplistic physically based equation but also to leverage the flexibility of machine learning. Additionally, this method enables us to circumvent detailed power system modelling which requires significant computing power and extensive data.

We found that the performance of our hybrid hydropower model surpasses the simple physics-based hydropower equation at most hydropower plant sites. Key findings highlight the significant losses of hydropower generation during major historical drought events across the globe.

How to cite: Shah, J., Hu, J., Edelenbosch, O., and van Vliet, M.: Global loss in global hydropower supply under droughts using a hybrid model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8551, https://doi.org/10.5194/egusphere-egu24-8551, 2024.

EGU24-9612 | PICO | HS5.2.3

Modernising RoR Hydropower: A Study on Retrofitting Aged Turbines for Optimal Performance 

Solomon Brown, Veysel Yildiz, and Charles Rougé

Hydropower stands out as an economical, reliable, sustainable, and renewable source of energy. It has been the leading source of renewable energy across the world, generating more than 15 % of total electricity in 2022. Therefore, it will likely play a crucial role as the energy system shifts towards a carbon-free future. The turbine system is at the heart of the hydropower plant and converts flowing water into mechanical energy. Remarkably, around 154 gigawatts, or one-fifth of the installed hydropower turbines, will be more than 55 years old by 2030 globally. Modernising these aged turbines is essential for sustaining optimal plant performance and this will create opportunities to retrofit hydropower facilities to improve their adaptability to changing hydrological conditions. A well-defined methodology is necessary to evaluate feasibility and select optimal solutions for upgrades. 

This study addresses this critical necessity in the context of run-of-river (RoR) hydropower plants with the HYPEROP toolbox to efficiently evaluate and choose optimal turbine replacement or upgrade options. HYPEROP provides operational optimization capabilities coupled with design flexibility and expanded simulation features for complex turbine configurations. It facilitates the selection of turbine systems featuring large and small turbines. The effectiveness of this toolbox is illustrated through the  case study of the Bonnington RoR hydropower plant, commissioned in 1927 on the upper reaches of the River Clyde in Scotland, United Kingdom. Bonnington RoR features a pair of two identical Francis turbines, each designed for a discharge of 12 m³/s and equipped with an installed capacity of 5.5 MW.

Our analysis indicates that, by prioritising Net Present Value (NPV) maximisation through a single objective function and considering historical discharge records, HYPEROP offers a novel configuration featuring non-identical Francis turbines with design discharges of 16.13 and 9.13 m³/s.  Optimal design increases power production by approximately 3.4 GWh (~7 %) annually by providing operational flexibility and retaining high efficiency over a range of discharge values. The optimal design yields an NPV of approximately 3 million dollars (USD), factoring in the additional energy increase as revenue, turbine replacement cost, and lifetime operation cost. The payback period for this investment is projected to be 15 years when considering only the additional energy as revenue. It's worth highlighting that the optimised design notably outperforms the current configuration, particularly in response to variable streamflows, including both high and low flows. Therefore, optimal design is expected to be less vulnerable to climate change due to higher efficient configuration. 

How to cite: Brown, S., Yildiz, V., and Rougé, C.: Modernising RoR Hydropower: A Study on Retrofitting Aged Turbines for Optimal Performance, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9612, https://doi.org/10.5194/egusphere-egu24-9612, 2024.

EGU24-9908 | ECS | PICO | HS5.2.3

Vary me a river: investigating the impacts of climate variability on hydropower and electricity systems planning in Switzerland 

Yann Yasser Haddad, Lukas Gudmundsson, Elena Raycheva, Jonas Savelsberg, Tobias Wechsler, Massimiliano Zappa, Gabriela Hug, and Sonia Isabelle Seneviratne

Clean and renewable energy systems play a pivotal role in climate change mitigation strategies. Nevertheless, climate change constitutes a threat to current and future supply of clean energy.  

In this study, we investigate how climate variability affects hydropower production and electricity systems planning in Switzerland. As the “water tower of Europe”, Switzerland encompasses a wide range of hydro-climatological conditions and showcases a high share of hydropower in its energy mix, making it a relevant case study.

Focusing on all hydropower plants with a capacity > 300 kW, we used daily runoff simulations from the PREVAH model, at 500 m resolution spanning 1991-2022, to estimate water availability and hydropower production for each power plant. The climate-impacted hydropower production time series are then given as input to Nexus-e, an integrated electricity systems modeling framework. This enables us to model the future state of the electricity system in Switzerland while considering climate variability.

Our method provides an accurate estimation of national hydropower generation and its variations. The integration of climate informed inputs into Nexus-e yields strong impacts on simulated investments in renewable energy and economic indicators such as power prices and imports/exports. Notably, in case of a projected decrease in hydropower generation due to increased drought occurrence, an increase in wind turbine and alpine PV capacity is needed to meet electricity demand. This scenario poses several societal and political questions regarding the implementation of a resilient energy system for Switzerland in the context of increasing changes in the climate system and pressure on ecosystems and biodiversity.

How to cite: Haddad, Y. Y., Gudmundsson, L., Raycheva, E., Savelsberg, J., Wechsler, T., Zappa, M., Hug, G., and Seneviratne, S. I.: Vary me a river: investigating the impacts of climate variability on hydropower and electricity systems planning in Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9908, https://doi.org/10.5194/egusphere-egu24-9908, 2024.

EGU24-9926 | PICO | HS5.2.3

Climate change, water resources and the hydropower system in Iceland 

Andri Gunnarsson, Hörður B. Helgason, Óli G. B. Sveinsson, and Gunnar G. Tómasson

In Iceland, hydropower represents around 72% of the gross electricity generation annually, with energy production capabilities around 13.8 TWh/a. Most of the hydropower infrastructure is in the central highlands, relying on water resources temporarily stored as snow and ice. These resources are vulnerable to climate change, projected to undergo substantial changes in the coming decades. Changes in flow volumes, seasonality of flow and extremes will have a strong impact on the hydropower system in Iceland as over 50% of inflow energy to the system originates from glacier ablation during summer. The high natural climate variability and energy system isolation pose a risk to the energy security of the power system as droughts and cold periods are usually not foreseen with great advance. Changes in hydrological flow dynamics, e.g.: onset of snow- and glacier melt, melt magnitudes and precipitation patterns pose a series of challenges for the hydropower system.

In glacier-dominated catchments, climate warming will initially increase glacier meltwater runoff to a maximum and then runoff will reside as the glacier area and volume decrease over time. The timing of the discharge peak is influenced by the catchment topoclimate characteristics and location. Understanding and quantifying these changes is important both for operational control and planning of energy infrastructure on shorter timescales (days, months, years) and climate change adaptation, on longer time scales, for both current energy projects as well as future development to maximize efficient water resource utilization.

To assess the impacts of changes in inflow dynamics on the hydropower system, hydrological models were developed to create inflow scenarios. Historical inflows were first reconstructed, followed by a construction of future runoff scenarios using climate projections and different glacier geometry evolution. This allowed for the assessment of meltwater-induced changes in runoff, although generally increasing in the next decades, certain areas are closer to reaching maximum meltwater production and will decrease in the coming decades. In all cases meltwater-induced increase in runoff is temporary, while large uncertainties exist with the timing of maximum peak inflow.

Utlization of the inflow scenarios created include current day operation to optimize reservoir management strategies and the design of future power projects, including refurbishments and capacity increases. This accommodates the expected increased flow rates 10–50 years into the future.

 

 

 

How to cite: Gunnarsson, A., Helgason, H. B., Sveinsson, Ó. G. B., and Tómasson, G. G.: Climate change, water resources and the hydropower system in Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9926, https://doi.org/10.5194/egusphere-egu24-9926, 2024.

EGU24-14292 | ECS | PICO | HS5.2.3

Deriving dynamic reservoir operating policy under the changing precipitation and inflow patterns in snow-dominated Himalayan regions  

Balasundaram Pattabiraman and Kasipillai Sudalaimuthu Kasiviswanathan

The impacts of climate change and complex local weather in the Himalayan region tend to change the characteristics of the precipitation, leading to a high non-stationarity. While studies have been performed to analyse the change in the rainfall pattern due to climate change, no attempts were made for the quantifiable impacts linking with reservoir operating policy. The assumption of stationary while deriving the operating policy of reservoirs is prevalent due to less computational effort. Reservoirs built for hydropower generation is expected to meet the energy demands that largely varies. Thus, adopting the conventional stationary operating policy derived based on the historical data might lead to create a havoc leading to underutilized when the reservoir operation is mainly meant for hydropower generation. In this study, the influence of alterations in the meteorological and inflow pattern on the dynamics of operation policy is explored for the reservoirs located in the snow dominated Himalayan region (Tehri reservoir). To demonstrate the proposed simulation optimization framework, the daily gridded rainfall data (0.25o x 0.25o) for the period 1901 - 2021 collected from Indian Meteorological Department and monthly inflow of tehri reservoir for the period 1965 - 2021 was used.  Several statistical methods were employed to quantify the alterations in the precipitation data and inflow to the reservoirs. A stochastic optimization algorithm was applied to derive the dynamic reservoir rule curves for maximizing the hydropower generation including the weighted over-shifting and seasonality. The statistical analysis of both precipitation and inflow shows negative trend during the drawdown periods (January, March, October, and December) with a mean release of 170 MCM. Further, the alteration in precipitation and inflow is dynamically accounted in operating policy under two release scenarios (i.e. scenario 1 by increasing reservoir release (10%, 20%, 30%) in the negative trend period and decreasing release in the positive trend period and scenario 2 by only increasing release during negative trend period). It is found that the scenario 2 (only increase in release) have resulted in higher hydropower generation. In addition, the changing pattern of the precipitation and inflow is performed by superimposing principle the assessed similar performance in hydropower generation. The outcome of the study indicates the adaptivity of developed framework and applied in other reservoirs under changing environment.

Keywords: Reservoir Operation, Rule curve, Pumped storage, Hydropower.

How to cite: Pattabiraman, B. and Kasiviswanathan, K. S.: Deriving dynamic reservoir operating policy under the changing precipitation and inflow patterns in snow-dominated Himalayan regions , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14292, https://doi.org/10.5194/egusphere-egu24-14292, 2024.

EGU24-15780 | ECS | PICO | HS5.2.3

Hydrological flow modelling with SWAT: a useful GIS based tool to assess hydropower production. 

Arianna Paschetto, Chiara Caselle, Sabrina Bonetto, and Claudia Leso

Europe's pursuit of climate neutrality by 2050 necessitates innovative strategies in renewable energy deployment. The European Union has championed policies to harness clean energy sources as hydroelectric energy. This study delves in Piedmont region (North-West of Italy), evaluating its residual potential for run-of-river hydroelectric plants.

 

More in detail, the research focuses on the Sangone catchment, aiming at performing a regional-scale study made to identify the best sites for potential hydroelectric plants. To ensure alignment with European Union biodiversity and environmental conservation directives, particularly the Habitats Directive and Birds Directive, the research prioritizes sites that are not in areas dedicated to environmental protection.

Moreover, the study includes landscape analysis and evaluation of geological and geomorphological constraints, such as landslide and hydraulic hazard, and technical and economic feasibility of plants.

After that, utilizing freely accessible data encompassing temperature, precipitation, land use, and soil characteristics specific to Piedmont, the study employed the Soil and Water Assessment Tool (SWAT).This GIS-integrated hydraulic model extrapolated flow rate metrics for water catchment areas devoid of direct measurement, optimizing site selection for maximal hydroelectric energy yield.The simulation used 17 years of meteorological data from 42 measuring stations and the model was run over the Sangone stream catchment. The model has also been calibrated to simulate runoff in the Sangone catchment. The outputs divide the stream in sections with equivalent potential power production.

 

Preliminary findings underscore the effectiveness of SWAT by using free data and free tools. It can be a useful planning tool for hydropower implementation by locating sites suitable for run-of-river plants, considering environmental impact and geo-hydrological hazard. As Europe navigates its green transition, such integrative approaches emphasize the feasibility and sustainability of hydroelectricity as a linchpin in the continent's renewable energy matrix.

How to cite: Paschetto, A., Caselle, C., Bonetto, S., and Leso, C.: Hydrological flow modelling with SWAT: a useful GIS based tool to assess hydropower production., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15780, https://doi.org/10.5194/egusphere-egu24-15780, 2024.

EGU24-20054 | ECS | PICO | HS5.2.3

Machine learning power system emulation for rapid screening of multi-sector policies 

Adil Ashraf, Mikiyas Etichia, Mohammed Basheer, and Julien Harou

Linking integrated water-energy simulation with multi-objective search algorithms provides a practical design tool for interdependent river basins and power systems. However, this approach is typically limited by the computational resources required to complete the many thousands of simulations to discover efficient solutions. We introduce an artificial neural network-based power system emulator to enable optimized design of large-scale detailed multi-sector water-energy systems. The proposed framework links an integrated power system emulator and river system simulator to an AI-driven multi-objective search design process. We compare optimized designs using both the power system emulator and simulator to check the emulators’ computational speed and accuracy. The framework is applied to the Sudanese power system and its link to the Eastern Nile river basin, to investigate how optimized operational strategies of the Grand Ethiopian Renaissance Dam (GERD) could affect Sudan’s resource systems. Results are similar for the power system emulator and simulator, showing the emulator helps to significantly reduce the computational cost of using sophisticated multi-sector policy design approaches.

How to cite: Ashraf, A., Etichia, M., Basheer, M., and Harou, J.: Machine learning power system emulation for rapid screening of multi-sector policies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20054, https://doi.org/10.5194/egusphere-egu24-20054, 2024.

ERE3 – Geo-storage

The need to find sufficient capacity for geological storage of carbon dioxide (CO2) to meet demand means less-than ideal, heterogeneous reservoirs need to be considered. Many such reservoirs are apparently compartmentalised by inter-layers, which may help, or hinder, CO2migration and storage capacity, depending upon their nature. The impact of shale inter-layers of thicknesses below seismic resolutions are generally neglected in plume migration simulations, but have been shown here to be important. Only simulations of plume migration that include the full coupling of all three of mass transport, geo-chemical and geo-mechanical processes together provide proper prediction of the barrier efficiency of relatively thin shale inter-layers. A series of feedback inter-actions, between these three process types, has been studied in detail, and, for example, leads to the unexpectedly higher barrier efficiency of relatively thin inter-layers compared to slightly thicker inter-layers. The results showed that changes to the capillary breakthrough pressure, together with diffusion processes, played the vital roles in enhancing the migration of the CO2 plume via the thicker shale inter-layers towards the overburden. This presentation identifies significant research gaps regarding the effects of complicated, intricate processes affecting shale inter-layer (or seal) integrity under realistic reservoir conditions.

How to cite: Alsayah, A.: Impact of CO2 Permeation on Inter-layers and Reservoir Cap-rock Sealing Efficiency, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-178, https://doi.org/10.5194/egusphere-egu24-178, 2024.

EGU24-205 | ECS | Orals | ERE3.1

Oil and gas wellbore leakage in Canada: key reporting uncertainties and measurement knowledge gaps 

Scott Seymour, Donglai Xie, and Mary Kang

Depleted oil and gas formations and associated wells can be exploited for use as energy or carbon dioxide storage infrastructure. However, a loss of wellbore integrity can result in the uncontrolled migration of fluids out of the well, risking groundwater contamination and releasing greenhouse gases (e.g., methane, carbon dioxide, hydrogen) into the atmosphere. In Canada, emissions specifically related to wellbore integrity and subsurface-based leakage have been monitored, measured, and reported by the oil and gas industry for more than a decade, resulting in some of the largest datasets to track such wellbore emissions. While these reporting systems were not necessarily designed to track methane emissions, both the provincial and federal governments nevertheless use these data to estimate methane emissions associated with subsurface wellbore leakage.  Moreover, incomplete reporting by the industry has resulted in highly uncertain methane emission magnitudes, and attempts by federal and provincial governments to resolve these issues yield emission estimates varying by more than a factor of two. Further, poorly understood emission mechanisms are likely to yield even more uncertainty in total emissions from wellbore leakage.

In this presentation, we illustrate the highly uncertain nature of methane emissions due to subsurface wellbore leakage in Canada using industry-reported data for the provinces of Alberta and British Columbia, regions covering more than 80% of crude oil and 95% of natural gas production nationally. We illustrate the sensitivity of these methane emission estimates using a variety of assumptions employed by the different governments for incomplete data, highlighting the key knowledge gaps for this source of emission. The different assumptions result in estimates varying by a factor of 3, and more troublingly, connotate fundamentally different understandings about wellbore leakage causes, sources of fluid, and progression of emission rates over time. We make initial recommendations for wellbore leakage monitoring and measurements to improve Canada’s methane quantification but with more broad applicability for monitoring well fluid leakage more generally.

How to cite: Seymour, S., Xie, D., and Kang, M.: Oil and gas wellbore leakage in Canada: key reporting uncertainties and measurement knowledge gaps, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-205, https://doi.org/10.5194/egusphere-egu24-205, 2024.

EGU24-982 | ECS | Orals | ERE3.1

Exploring Hydrogen Storage Strategies in Geological Formations to Minimise Gas Mixing 

Harri Williams, Niklas Heinemann, Ian Molnar, Fernanda Veloso, Carl Boardman, Toni Gladding, and Tarek Rashwan

Large-scale H2 storage within porous geological formations – such as depleted hydrocarbon reservoirs – presents a practical opportunity leveraging existing energy industry infrastructure to address renewable energy intermittency (e.g., from wind and solar). H2 can be generated from excess renewable energy, stored in these reservoirs, and drawn when needed. Depleted gas reservoirs have proven to trap gases (e.g., natural CH4) over geological timescales, and have been used for large-scale CH4 storage. The working gas (i.e., H2) is the fraction that is injected, stored temporarily, and produced from the reservoir. The cushion gas, the share of the injected gas that remains in the reservoir to maintain operational pressures and drive the production, represents an initial investment in the storage operation. Therefore, because H2 is relatively expensive, the use of a cheaper alternative cushion gas – such as CO2 and / or in-situ CH4 – can reduce the investments needed. Furthermore, the use of CO2 storage can simultaneously contribute to Net-Zero goals (as the CO2 will remain fixed in the reservoir).

One of the main challenges associated with the use of alternative cushion gases in these storage systems is the mixing with the working gas. Increased mixing will increase the cost of separation after production. In this study, we explore how the mixing of cushion and working gas can be minimised by using the reservoir geometry of laterally extensive reservoirs such as the Southern North Sea gas fields. Ultimately, the reservoir architecture and the infrastructure will dictate the extend of the contact area between the cushion and working gases, and by reducing this, the risk of mixing will be reduced. This work proposes an alternative operational strategy that investigates the storage of H2 working gas and CO2 cushion gas in a depleted system, where both gases are kept separated by injecting them at opposing ends of a reservoir to reduce the surface area of the mixing gas interface.

How to cite: Williams, H., Heinemann, N., Molnar, I., Veloso, F., Boardman, C., Gladding, T., and Rashwan, T.: Exploring Hydrogen Storage Strategies in Geological Formations to Minimise Gas Mixing, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-982, https://doi.org/10.5194/egusphere-egu24-982, 2024.

EGU24-1539 | ECS | Orals | ERE3.1

Development of a site-screening method for hydrogen storage purposes and its application to an industrial dataset of Italian reservoirs 

Riccardo Maria Ridolfi, Salvatore Azzaro, Stan E. Beaubien, Andrea Da Pra, Marco Pontiggia, and Sabina Bigi

The use of hydrogen as an energy carrier will require effective storage solutions, and depleted hydrocarbon reservoirs offer a safer and cheaper large-scale option compared to other possibilities. The selection of a site for underground hydrogen storage (UHS) entails considerable responsibilities and expenses, and specific tools should be employed to facilitate and optimize the decision process. Thus, a site-screening method was developed to rank depleted and almost depleted hydrocarbon reservoirs for UHS, with subsequent testing on a confidential dataset of 48 production sites from Italy provided by Eni. A set of 27 screening parameters was selected from a wider dataset and a weight for each one was defined by reproducing the Analytic Hierarchy Process (AHP) in Microsoft Excel and gathering expert judgements from both academic and industry following the Delphi technique. This was performed from the points of view of HSE (health, safety, and environment), geotechnical performance (GP) and economic performance (EP), dividing the individual parameters among these three supergroups and normalizing the diverse kinds of dataset records to be used in the calculation procedure. The method resulted in three preliminary rankings based on the sites’ HSE, GP and EP scores and a comprehensive ranking obtained through the aggregation of these three scores for each site, with penalties applied if specific, adverse features exist for UHS purposes. For sites with incomplete data, an estimation of the potential score was derived based on average values calculated from the dataset and attached as additional information to the screening scores without affecting the ranking. The AHP results highlighted a major role for Faulting Description, Mineralization Type, Onshore/Offshore, Wells Number, Reservoir Architecture, Datum Depth and Initial Pressure at Datum, even though other factors made significant contributions. The result consists of a set of scores ranging from 29 to 72 out of 100. To assess the reliability of the method, two blind tests were conducted on a minor proprietary dataset containing well-known sites from North Africa, the first involving a subset of the sites and the second using all sites. The results yielded a good match with the existing ranking performed by Eni. The developed method can be adjusted for a variety of decision-making scenarios, to accommodate changes in the screening purposes or advancements in research. In this configuration, it consists of a highly effective tool for an objective and transparent screening of sites for UHS purposes.

How to cite: Ridolfi, R. M., Azzaro, S., Beaubien, S. E., Da Pra, A., Pontiggia, M., and Bigi, S.: Development of a site-screening method for hydrogen storage purposes and its application to an industrial dataset of Italian reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1539, https://doi.org/10.5194/egusphere-egu24-1539, 2024.

EGU24-1927 | ECS | Orals | ERE3.1

Geological modelling and reservoir simulation workflows for hydrogen geostorage in depleted gas fields, Aotearoa New Zealand 

Matt Parker, David Dempsey, Jinjiang Liu, and Andy Nicol

Underground storage of green hydrogen in depleted gas fields could provide Aotearoa New Zealand (ANZ) with a storage option critical for meeting peak energy demands and realising green hydrogen ambitions. During early de-risking of specific sites, it is important to develop an accurate geological model to test whether the reservoir has the desired containment, volume and hydrogen deliverability. However, where seismic reflection lines and well data are limited and/or the storage system is structurally complex, the resulting geological models may be non-unique. Therefore, injection and withdrawal simulations using different structural end members is critical to constrain how a hydrogen plume may flow within (and out of) the container and interact with existing reservoir fluids.

Here we present workflows for modelling a multi-year injection and withdrawal cycle of hydrogen into a depleted gas field. We use data from the Tariki Sandstone Member of the Ahuroa field in the Taranaki Basin, currently used to store natural gas in ANZ. This reservoir is located 2 km deep at the crest of an anticline above a major thrust fault, with marine mudstones forming the top seal and low-permeability fault rock the lateral seal. With only mixed quality 2D seismic reflection lines and a tight well cluster, the precise geometry of the thrust fault and its relations to smaller secondary faults is poorly constrained.

To capture this uncertainty in our simulations, we have developed two 3D geological models of the Ahuroa field in Leapfrog Energy software. We use these geological models to conduct dynamic simulation of hydrogen injection and withdrawal using the massively-parallel simulator PFLOTRAN-OGS. We develop simulations that allow us to, over a 10-year cycle, test for closure or spill into adjacent fields, and predict the amount of mixing with remnant natural gas and formation water. During the simulations, we see major differences between the two geological models related to cushion injection and working H2 volumes, rates of water production and impurities due to natural gas. Additionally, one model has high risks of unrecoverable H2 gas loss when over-pressurised. Finally, we reimport the results back into Leapfrog for visualisation of the behaviour of the two hydrogen plumes over time.

How to cite: Parker, M., Dempsey, D., Liu, J., and Nicol, A.: Geological modelling and reservoir simulation workflows for hydrogen geostorage in depleted gas fields, Aotearoa New Zealand, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1927, https://doi.org/10.5194/egusphere-egu24-1927, 2024.

EGU24-2031 | ECS | Orals | ERE3.1

4D visualisation and analysis of fluid-rock interactions in a caprock for the implication of carbon sequestration and storage 

Jingyue Hao, Lin Ma, Takshak Shende, Cathy Hollis, and Kevin Taylor

The assessment of caprock sealing capability is a crucial component for the safety evaluation of geological carbon storage. This study imaged and modelled acid-rock interactions in a mudstone utilising time-lapse X-ray 3D imaging techniques and direct simulation at micro-scale, providing a unique perspective to comprehend the reality and predict the outcome of this topic. Different acid concentrations were used to mimic a range of possible acid concentrations during CO2 injection and storage. Changes observed in samples subjected to acid interaction include initial closure of pre-existing fractures, followed by growth of existing-fractures and slight sample swelling. Due to the heterogeneity of mudstone, acid migration and dissolution followed preferential pathways such as along laminations or fractures. The reactive transport models demonstrate that the majority of dissolution occurs in close proximity to the inlet, while downstream of the fracture, primarily owing to the reduction of H+ concentration along the fluid pathways. The distribution of dissolved areas is primarily controlled by carbonate distribution within the sample. Carbonates located near fractures dissolved first and contribute to the connection of individual fractures. Both the experimental and numerical data indicate that calcite dissolution rate and dissolution front migration rate decrease with time. Numerical results demonstrate a significant decrease in shear stress after acid injection, especially with low-pH acids, resulting in slower fluid flow behaviour. Consequently, the mobile and immobile zones of fluid flow were predicted based on image and modelling results. The acid moved slowly and stayed longer in immobile zones, leading to more extensive calcite dissolution than in mobile zones. The study of fluid-rock interaction provides a valuable analogue for predicting the microstructural changes that may occur in a caprock after CO2 injection. It is worth noting that the risk of leakage is likely exacerbated by the development of fractures induced by acidic interaction.

How to cite: Hao, J., Ma, L., Shende, T., Hollis, C., and Taylor, K.: 4D visualisation and analysis of fluid-rock interactions in a caprock for the implication of carbon sequestration and storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2031, https://doi.org/10.5194/egusphere-egu24-2031, 2024.

Underground hydrogen storage (UHS) is proposed as a carbon-free energy source derived from renewable solar and wind energies. Deep saline aquifers are proposed for UHS since can potentially contribute to large-scale renewable energy storage, providing high storage capacities required to buffer seasonal energy demands. The caprock plays an important role in the sealing capacity for safe and effective UHS. The geochemical reactions involved in H2-saline groundwater-rock interaction are significant for the integrity of the caprock as these processes directly determine the sealing capacity during UHS.

Aqueous H2 could react with minerals and trigger redox and dissolution/precipitation reactions, which may affect the permeability and porosity of the caprock. The resulting changes reactivate or propagate microfractures and, consequently, affect the integrity of the caprock and the long-term storage stability. UHS in formations with sulfate-rich groundwater can induce an increase in pH due to sulfate reduction (i.e., SO42- + 4H2 = HS- + 3H2O + OH-). The main goal of this work is to study the effect of the increase in pH (HS--rich water) on a marly limestone caprock.

The PHREEQC code and the phreeqc.dat database were used to simulate equilibrium of H2 (at any pressure in a range between 1 and 100 bar) with a saline solution in equilibrium with calcite and gypsum at 60 °C. The thermodynamic calculations show that H2 reduces sulfate and that the pH increases from 8.2 to 11.1. This high alkaline water could, therefore, affect the integrity of the caprock. We tried to prove the model results (sulfate reduction and pH increase) in a batch experiment. A saline water rich in sulfate was put in equilibrium with H2 at 3 bars. After a week, however, the pH did not increase, suggesting that the short-term sulfate reduction does not occur in the absence of sulfate-reducing microorganisms.

A column experiment was carried out to observe potential changes in the marly limestone in contact with an alkaline (pH ≈ 12), HS--rich solution at 60 °C. Circulation of the solution led to a release of Si and Al, i.e., dissolution of quartz and aluminosilicates. After 380 h, an increase in the flow rate (from 0.01 to 0.03 mL min-1) resulted in a decrease in the concentrations of Si and Al, suggesting a far-from-equilibrium dissolution of the silicates (SIquartz = -2.8; SIalbite = -5.9 and SIillite = -10.6) although the solution was supersaturated with respect to chlorite (SIchlorite = 5-12). The dissolution of silicates at highly alkaline (pH ≈ 12) may result in a variation of the initial properties of the UHS caprock (e.g. porosity, permeability). Numerical and experimental results of ongoing column experiments will help reveal the extent of the rock alteration.

How to cite: Ceballos, E., Cama, J., and Soler, J. M.: Reactivity of a marly-limestone caprock in contact with an alkaline HS--rich solution: application to hydrogen storage in a saline aquifer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2537, https://doi.org/10.5194/egusphere-egu24-2537, 2024.

EGU24-3599 | Orals | ERE3.1 | Highlight

Managing Large-Scale Geologic Storage of CO2 in the United States: Geomechanical Impacts, Basin-Scale Coordination, and Regulatory Implications 

Jens Birkholzer, Yves Guglielmi, Abdullah Cihan, Jonny Rutqvist, Stanislav Glubokovskikh, Matt Reagan, Preston Jordan, Utkarsh Mital, Meng Cao, and Hafssa Tounsi

After decades of research on geologic carbon storage (GCS), the world seems to be moving from pilot tests and demonstration experiments to industrial-scale implementation. In the United States, the Bipartisan Infrastructure Law passed in 2021 contributes $2.5 billion for carbon storage commercialization in addition to similarly large investments in point-source carbon capture as well as direct air capture. These federal investments, combined with new tax credits provided by the 2022 Inflation Reduction Act, provide a significant push towards GCS deployment over the coming years and decades, likely creating multiple large storage projects or clusters of integrated projects across hydrogeologic basins. These projects will likely involve injection volumes that may result in large-scale pressure increases in the subsurface and may cause unwanted geomechanical effects, such as generating seismic events and seal integrity concerns per reactivation of critically stressed faults.

Here, we will focus on such large-scale deployment hurdles and discuss related regulatory challenges, using the United States permitting framework as an example. We will begin by illustrating basin-scale pressure impacts expected from geologic carbon sequestration at scale, based on regional modeling studies of future GCS scenarios. With regards to geomechanical implications, we will briefly present lessons learned from two recent field tests—one being a controlled fluid (water and CO2) injection fault slip and leakage experiment in a clay (sealing) formation, the other a CO2 storage demonstration site where micro-seismicity has occurred along pre-existing basement faults. We will then introduce ongoing work to transfer the knowledge derived from these experiments to larger injection volumes and scales so that ultimately geomechanical effects can be assessed and coordinated at the scale of large storage complexes. In terms of regulatory implications, we will review the regulatory framework for CO2 storage wells in the United States and discuss how suitable it is (or not) for permitting a GCS future where sedimentary basins with interconnected reservoirs might host multiple large storage projects. Lastly, we will propose a hierarchical permitting approach for such situations, which would add a general permit for regional coordination of subsurface resources to the existing framework for permitting of individual CO2 storage projects.

How to cite: Birkholzer, J., Guglielmi, Y., Cihan, A., Rutqvist, J., Glubokovskikh, S., Reagan, M., Jordan, P., Mital, U., Cao, M., and Tounsi, H.: Managing Large-Scale Geologic Storage of CO2 in the United States: Geomechanical Impacts, Basin-Scale Coordination, and Regulatory Implications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3599, https://doi.org/10.5194/egusphere-egu24-3599, 2024.

EGU24-4135 | ECS | Posters on site | ERE3.1

Novel application of artificial neural networks to derive lithofacies in the Bunter Sandstone Formation of the UK Southern North Sea 

Zhenghong Li, Mads Huuse, Kevin Taylor, and Lin Ma

The Bunter Sandstone Formation (BSF) in the UK sector of the Southern North Sea is thought to have a significant potential for CO2 storage, which would help the UK achieve net-zero carbon emissions by 2050. During the assessment phase, a robust lithofacies classification scheme and accurate identification enable better control for delineating the petrophysical property distribution in 3-D space, which is vital for further estimating the storage capacity and simulating CO2 migration.   

In previous studies, several different lithofacies classification schemes were proposed for calculating the CO2 storage capacity of BSF traps. However, the establishment of these schemes was almost entirely dependent on well-logging data due to limited cores and corresponding thin sections. For example, the ‘cemented sandstone layers’ were identified only by low gamma-ray values with a sharp increase in density values and a decrease in acoustic values, which leaves significant uncertainty because of the lack of detailed lithological description and core calibration. For lithofacies identification based on well-logs, artificial neural networks are of great potential due to their strong non-linear mapping ability. Numerous researchers used the fully connected neural network (FCNN) to recognize lithofacies, but this method can only construct point-to-point mapping, which cannot take into account the previous information (data points in well-logs) of sequence data and results in not being fully competent in lithofacies identification.

This study aims to partition the BSF reservoirs into several relatively homogeneous lithofacies based on cores, thin sections, SEM (Scanning Electron Microscope) and XRD (X-ray Diffraction) analysis. We summarize each lithofacies characterization including grain size, porosity/permeability, 3D network structure of pore and cement determined by X-ray CT. Data pairs composed of logs and corresponding lithofacies types are selected for training neural networks. On this basis, we employ the algorithms designed for sequence data to achieve lithofacies identification, and make a comparison with the widely used FCNN method.

How to cite: Li, Z., Huuse, M., Taylor, K., and Ma, L.: Novel application of artificial neural networks to derive lithofacies in the Bunter Sandstone Formation of the UK Southern North Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4135, https://doi.org/10.5194/egusphere-egu24-4135, 2024.

EGU24-4703 | Posters on site | ERE3.1

Carbon sequestration potential of the Mae Moh mine, Northern Thailand 

Piyaphong Chenrai

The main source of carbon dioxide (CO2) emissions in Thailand is the energy sector, particularly coal-fired power plants. The Mae Moh lignite-fired power plant, owned by the Electricity Generating Authority of Thailand (EGAT), stands out as the primary point source of CO2 emissions in the energy sector. Situated in Northern Thailand, this power plant relies on lignite supplied from the Mae Moh lignite open-pit mine in the same vicinity. Consequently, this study conducts a preliminary assessment of the geological CO2 storage potential of the Mae Moh mine, evaluating its suitability as a CO2 storage site. The concept of CO2 sequestration in unmineable coal seams is considered as a potential approach to mitigate CO2 emissions by injecting CO2 into these seams. While a substantial portion of the remaining coal at the Mae Moh mine may still be extractable through traditional methods, the feasibility of opening new mines is uncertain. This study aims to evaluate the suitability of coal seams for CO2 storage, taking into account geological, technical, economic, and safety criteria. The findings of this study are anticipated to contribute to an enhanced understanding of carbon sequestration in coal seams in Thailand.

How to cite: Chenrai, P.: Carbon sequestration potential of the Mae Moh mine, Northern Thailand, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4703, https://doi.org/10.5194/egusphere-egu24-4703, 2024.

EGU24-4735 | ECS | Posters on site | ERE3.1

Spreading and mixing of hydrogen in heterogeneous porous media 

Alejandro Fernandez Visentini, Luis Cueto-Felgueroso, Juan Jose Hidalgo, and Marco Dentz

The efficiency of hydrogen storage and recovery cycles largely depends on how the fluid spreads as it is injected in the reservoir, and how well it mixes with the in-situ fluids. Spreading leads to the stretching of the fluid front and to the creation of chemical concentration gradients, whereas mixing is driven by the existence of such gradients and it tends to erase them by molecular diffusion. Spreading is caused by spatial heterogeneity in the gas flow velocity, which in turn depends on the spatial distribution of the host rock permeability, the latter exhibiting orders of magnitude variation over a wide range of spatial scales. Quantification of the impact of permeability heterogeneity on the spreading and mixing behaviour of gases can help to better predict the outcome of hydrogen production cycles, but it has not been systematically studied to date in the context of underground hydrogen storage. Further, the dependence on pressure and chemical composition of the hydrodynamic properties of gases, namely, viscosity, density and compressibility, leads to a non-linear relationship between spreading and mixing of hydrogen and permeability that requires detailed numerical modelling. Here, we investigate the dependence of standard spreading and mixing measures on the hydrodynamic parameters of evolving mixtures of hydrogen and other fluids (e.g., cushion gases, water) for different permeability models. We simulate isothermal hydrogen injection and extraction for different permeability models, imposed pressure gradients and regimes of flow stability (e.g., viscous and gravitational). We consider different test cases where invading and residing fluids go from mildly- to highly-contrasting hydrodynamic properties. The considered spectrum of spreading and mixing behaviours for given permeability models helps to develop uncertainty measures and analytical models. We perform the modelling using open-source Matlab Reservoir Simulation Toolbox (MRST).

 

How to cite: Fernandez Visentini, A., Cueto-Felgueroso, L., Hidalgo, J. J., and Dentz, M.: Spreading and mixing of hydrogen in heterogeneous porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4735, https://doi.org/10.5194/egusphere-egu24-4735, 2024.

Carbon capture and storage (CCS) holds the potential to mitigate carbon dioxide (CO2) emissions into the atmosphere. However, there is a likely accumulation of impurities generated from the corrosion reaction taking place within the pipelines during the injection process as well as during the transportation phase. Reactions can change the chemistry of injected fluids for storage, which can then react with the adjacent rock formations reservoir, affecting the reservoir porosity, permeability and caprock integrity. These are important parameters that determine the injectivity and storage capacities of deep geological sites for long term CO2 storage. The study is aimed at evaluating the upstream corrosion of the metallic pipeline materials, correlating their kinetics with changes in the injection fluid chemistry and evaluating the effect of these combined phenomena on the storage capacities of the geological reservoir rocks. The study involves the investigation and characterisation of corrosion and bulk scaling upstream to the deep geological formations of various rock types. Reservoir rock samples are characterised before corrosion and after carbonation reactions using X-ray Computed Tomography and other micro-analytical techniques, to assess the changes in the rock storage capacity properties such as porosity, pore connectivity and permeability. Our preliminary results indicate an increase in porosity, pore size and pore connectivity in pure sandstones compared to impure sandstones, indicating that local rock chemistry in an important factor in controlling dissolution/carbonation kinetics.

How to cite: Macente, A., Piazolo, S., and Pessu, F. O.: Understanding corrosion and carbonation effects on pore scale properties of geological reservoir rocks during CO2 injection and storage: Insights from X-ray Computed Tomography , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5455, https://doi.org/10.5194/egusphere-egu24-5455, 2024.

EGU24-5579 | Posters on site | ERE3.1

SHARP project – an integrated approach for assessing CO2 storage containment risks 

Tine B. Larsen, Elin Skurtveit, Steve Pearson, Tom Kettlety, Jung Chan Choi, Chen Huang, Brian Carlton, J. Michael Kendall, Michael Kupoluyi, Daniela Kühn, Daniel Roberts, Kees K. Hindriks, Anne-Kari Furre, Auke Barnhoorn, and Devendra N. Singh and the SHARP Team

SHARP is an interdisciplinary project with the overall aim to develop improved methods for quantitative assessment of subsurface CO2 storage containment risks. The project combines subsurface stress models, rock mechanical failure experiments, and seismicity observations with probabilistic modelling of fault stability, seismic hazard, and containment risk. This presentation will summarise and give a status update on risk quantification work of the SHARP project. Uncertainties and parameter ranges are included for the failure data, and independent and dependent failures of geological barriers are treated probabilistically. A new catalogue of natural seismicity in the North Sea form the basis for constructing offshore ground motion prediction equations (GMPEs) and an updated regional probabilistic seismic hazard analysis (PSHA). Natural seismicity, pressure, and pressure induced seismicity are identified as potential root causes of leakage (triggers) and a catalogue of generic release diagrams are built for realistic geological settings. The generic release diagrams are mapped onto test cases from the North Sea. The geological containment risk with uncertainties will be evaluated though event tree analysis and Monte Carlo runs, where the inputs are the quantified contributions from release diagrams, probabilistic fault stability analysis and the seismic hazard curve.

How to cite: Larsen, T. B., Skurtveit, E., Pearson, S., Kettlety, T., Choi, J. C., Huang, C., Carlton, B., Kendall, J. M., Kupoluyi, M., Kühn, D., Roberts, D., Hindriks, K. K., Furre, A.-K., Barnhoorn, A., and Singh, D. N. and the SHARP Team: SHARP project – an integrated approach for assessing CO2 storage containment risks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5579, https://doi.org/10.5194/egusphere-egu24-5579, 2024.

EGU24-6123 | ECS | Posters on site | ERE3.1

An Underground Hydrogen Storage Site Selection Ranking Matrix: Insight into the Friulian Plain, Italy 

Lorenzo Borghini, Amerigo Corradetti, Marco Franceschi, Anna Del Ben, and Lorenzo Bonini

Net-zero emission targets for 2050 are pushing governments, energy industries, and the scientific community to explore the use of alternative energetic vectors. Among them, hydrogen has risen as a potentially extremely relevant technology, as testified by the establishment of several “hydrogen valleys” in the EU. One of the key aspects in the use of hydrogen as energy vector is its underground storage. The majority of studies focus on physical experiments and numerical simulations, whereas little attention has been so far directed on potential sites selection. This study presents a site selection and feasibility study considering the Cavanella Formation (lower Miocene, Northeast Italy) as potential reservoir for hydrogen storage. This unit comprises medium to fine glauconitic sandstones. The presence of the Cavanella Formation in the subsurface of the Friuli Plain is widely documented and the unit is easily identified in seismic lines. A preliminary petrophysical characterization of the Cavanella Formation was carried out on sampling collected from outcrops. The site selection study was based on interpretation of publicly accessible seismic lines, well logs, thin sections, and literature data. Each potential site was evaluated, attributing a storage feasibility index through a designed scoring matrix developed by us and based on literature reservoir characteristics needed for hydrogen storage. Results suggest that the Cavanella Formation could have good petrophysical characteristics for hydrogen storage and that potential storage sites could exist. The scoring matrix has already been tested on underground hydrogen storage sites currently in use worldwide and has proven reliable. The identification of possible sites for hydrogen storage and their petrophysical characterization can have significant impact on the deployment of this new technology, therefore helping the energy transition to renewable sources.

How to cite: Borghini, L., Corradetti, A., Franceschi, M., Del Ben, A., and Bonini, L.: An Underground Hydrogen Storage Site Selection Ranking Matrix: Insight into the Friulian Plain, Italy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6123, https://doi.org/10.5194/egusphere-egu24-6123, 2024.

The end of coal mining activities in Germany has resulted in vast underground spaces becoming potentially available for alternative purposes. The reuse of underground space may therefore provide answers to a growing interest in terms of economic and environmental considerations. Underground spaces can play an important role in future renewable energy scenarios (e.g. electricity and heat storage) and they can be considered as sites for waste disposal and other goods.

One example in these scenarios is the use of abandoned coal mines as sites for future subsurface hydropower plants (UPSP). However, risks associated with underground cavity projects and hydropower plants are well known (Colas et al., 2023), and these may be the reason that there are only a few examples of reusing abandoned coal mines as UPSP. In any repurposing process for former coal mines, geological criteria necessary for a quantitative assessment of the usability of abandoned coal mines need to be established. We use in this study the former coal mine Prosper-Haniel, Ruhr Area, Germany, as a lab test case. The Prosper-Haniel mine covers an area of approx. 165 km², has a maximum depth of 1,159 m at 7 different levels of coal production and can be accessed by a total of five sinking shafts and one inclined shaft. Although the mine has been closed since 2018, feasibility studies have been carried out to investigate the potential reuse of the mine as a heat storage reservoir (Geo-MTES, 2018) and as a lower reservoir for a UPSP (Niemann et al., 2018).

We present an outline of geological and hydrogeological considerations essential for the repurposing of the abandoned coal mine Prosper-Haniel. The approach integrates stratigraphy data, fault sets, mine geometry, geological properties, and three-dimensional geological modelling. The envisaged repurposing applications encompass the utilization of Prosper-Haniel as a lower reservoir for UPSPs, a reservoir for heat storage, a geothermal production site, and as an underground space for storage purposes including waste disposal. The multi-disciplinary and integrated approach presented aims to contribute to a nuanced understanding of the potential repurposing opportunities associated with underground coal mines.

References

Colas, E., Klopries, E.-M., Tian, D., Kroll, M., Selzner, M., Bruecker, C., Khaledi, K., Kukla, P., Preuße, A., Sabarny, C., Schüttrumpf, H., and Amann, F., ‘Overview of converting abandoned coal mines to underground pumped storage systems: Focus on the underground reservoir’, JOURNAL OF ENERGY STORAGE, Vol. 73, 2023.

Geo-MTES, Studie zur thermischen Nachnutzung von Steinkohlebergwerken am Beispiel des Bergwerks Prosper-Haniel am Standort der Innovation City Bottrop. Teilvorhaben: Numerische Modellierung (FKZ 03ET1193B), 2018.

Niemann, A., Balmes, J. P., Schreiber, U., Wagner, H.-J., and Friedrich, T., ‘Proposed underground pumped hydro storage power plant at Prosper-Haniel colliery in Bottrop—state of play and prospects’, Mining Report Glückauf, Vol. 154, No. 3, 2018.

How to cite: Colas, E., Back, S., and Kukla, P.: Future underground spatial utilization – The role of geological criteria in the repurposing process of former coal mines, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8284, https://doi.org/10.5194/egusphere-egu24-8284, 2024.

EGU24-8870 | ECS | Posters on site | ERE3.1

Analogue and numerical modelling of rock deformation due to subsurface compressed gas storage  

James Johnson, Daniel Kiss, Reinier van Noort, and Viktoriya Yarushina

Storage of compressed gases in lined rock caverns (LRC) has been proposed in order to buffer the peaks of energy intake/output for industrial/renewable systems. LRCs consist of a thin (1-2 cm) steel liner to ensure gas tightness, surrounded by a concrete layer (0.5-2 m) to transmit stresses to the host rock which acts as a pressure vessel. Advantages of storage in such underground LRCs when compared to storage in tanks on the surface or on the seabed include (1) increased safety, and potentially (2) increased storage capacity.

Pilot studies exploring the feasibility for LRC storage have been carried out showing the potential for the technology (e.g. Grängesberg, Sweden​; Skallen, Sweden; ANGAS, Japan). All three test facilities demonstrated that it is possible to reach a gas pressure that is at least 20 times larger than the lithostatic pressure without compromising the integrity of the LRC. While these pilot tests are valuable for demonstrating the potential of the LRC technology, it is not possible to extrapolate safe operating conditions for future scenarios (e.g. shallower depths, different rock types). As a result, widespread adoption of LRC storage is hindered by uncertainty. Our focus is operating pressure, which scales roughly with storage capacity, and thus has a direct impact on LRC profitability.

In this study we will present results of analogue and numerical models. We focus on brittle deformation in the host rock due to the load exerted by a pressurized cavity. Our specific goal is to determine the extent of safely acceptable brittle deformation, and to identify useful indicators of storage integrity to be monitored during initial pressurization tests and continuous operation. Our analogue modelling of this system identifies key parameters that influence the potential success of these projects including (1) proximity to surface, (2) strength of the host rock, (3) mechanical anisotropy, (4) injection rate and amount, and (5) type of liner(s) applied. For the analogue modelling we use gelatin to represent a shallow competent host rock (e.g. granite, gneiss). A hole placed centrally on one side of the cell allows for the injection of compressed air. Utilizing a balloon placed within the hole, the compressed air acts on the liner until the stress applied by the forced air results in visible strain (i.e. fracturing). For the numerical modelling we use a 2D, visco-elasto-plastic, finite difference, hydro-mechanical code utilizing a pseudo-transient solver running on GPUs. The main goal is to cross-validate the results of the two independent methods, and to provide a straightforward way to extrapolate from laboratory simulation to real world conditions.

How to cite: Johnson, J., Kiss, D., van Noort, R., and Yarushina, V.: Analogue and numerical modelling of rock deformation due to subsurface compressed gas storage , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8870, https://doi.org/10.5194/egusphere-egu24-8870, 2024.

EGU24-9061 | ECS | Posters on site | ERE3.1

Geophysical Site Characterization and monitoring of CO2 mineralization in Basaltic Complexes, Helguvik, Iceland 

Jonas Simon Junker, Anne Obermann, Alba Zappone, Hansruedi Maurer, and Stefan Wiemer

In a pilot project (DemoUpStorage) in Helguvik, Iceland, CO2 is injected into basaltic strata using seawater instead of freshwater for CO2 dissolution. The aim is to obtain permanent storage of the CO2 by mineral carbonation. We aim to observe the precipitation of Mg and Fe carbonates in the porosity of the reservoir at depth. Additional to geochemical observations, we use geophysical methods (ERT, seismics) to monitor the mineralization process.

Here, we present the overall project, the geophysical characterization of the site and the first time-lapse monitoring results. We performed a cross-hole seismic traveltime tomography and single-hole electrical resistivity (ERT) measurements to characterize the study site in the target depth of 150m to 400m and to record a geophysical baseline for the time-lapse measurements. The seismic and geoelectric data are in good agreement, highlighting multiple basaltic layers of tens of meters in thickness with sedimentary interlayers. With the CO2 injection starting in early 2024, we will also show the first results from the (daily) time-lapse ERT surveys.

How to cite: Junker, J. S., Obermann, A., Zappone, A., Maurer, H., and Wiemer, S.: Geophysical Site Characterization and monitoring of CO2 mineralization in Basaltic Complexes, Helguvik, Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9061, https://doi.org/10.5194/egusphere-egu24-9061, 2024.

EGU24-9198 | ECS | Orals | ERE3.1

Integrated approach for hydrogen storage in a salt mine: the case of Realmonte, Sicily (Italy).  

Giuseppa Anzelmo, David Iacopini, Giovanni Mario Cella, Luca Visconti, Katriona Edlmann, Martina Cascone, Giacomo Russo, Rosanna Maniscalco, Mariano Parente, Cristian Sabatino, Claudia Di Benedetto, Abner Colella, Giuseppina Balassone, Piergiulio Cappelletti, Ciro Cucciniello, Lucia Pappalardo, Enrico Di Clemente, Laura Perrotta, Donato Giovannelli, and Michele Simili

The crucial role of hydrogen in future energy systems, particularly in balancing fluctuations in electricity generation, underscores the need for effective storage solutions. For the underground storage of chemical energy carriers such as hydrogen, the underground salt cavern is the sole underground space that has been successfully used as storage facilities. This study explores the potential of underground salt caverns for storing hydrogen. Salt caverns offer advantages such as low investment costs, high sealing potential, and minimal cushion gas requirements. Geological considerations, including a salt top depth of 400-600 m, >95% pure halite, a deposit thickness of 200-300 m, and a diapiric salt bank or internally homogeneous lenses, are necessary for successful cavern exploitation. From a microbial point of view, during the water evaporation process leading to the underground salt cavern formation, small parts of the in-situ brine become trapped in the salt and end up as fluid inclusions, potentially including halophilic microorganisms subsequently freed during the process of solution mining. Autotrophic microbial life is feasible under salt cavern circumstances, especially if a suitable electron donor like H2 is introduced.

The study focuses on a salt mine in Realmonte, Sicily and explores the geology, geochemistry, geomechanics and microbiology properties of the halite section. The mine, extracting 97% pure rock salt, serves as a natural laboratory for geochemical and geo-mechanical studies. It is characterized by four depositional units. Unit A comprises laminated gray halite (50 m); Unit B (100 m) features massive gray halite with kainite laminae up to 18m thick; Unit C (70-80m), consists of white halite layers separated by dark mud laminae and Unit D (60m) which includes anhydritic mudstone transitioning to an anhydrite laminite sequence. Utilizing well log data and a 3D geological subsurface model, the study reveals a salt bank with an average thickness of 500 m (of which only the upper 220 m b.s.l. is exploited) and defines the top and bottom of the halite subunits. Pore-perm analysis on 28 rock salt and kainite cores, including XRF analysis and Mercury Intrusion Porosity, provides insights into geochemical and porosity characteristics. Pore network model was obtained from the processing and interpretation of the micro-tomographic images collected on 10 rock salt and 1 kainite sample. A hydrogen injection test under varying conditions simulates cyclic storage under both static and dynamic conditions and a geochemical model of the internal conditions of a cavern has been produced using PHREEQC model.

Results indicate limited diffusion under relatively high pressure. Microbiology and the linked geochemistry of two salt cores, both from the Realmonte mine but of different composition, is being investigated. The integrated geochemical, geomechanical, microbiological and experimental data support the feasibility of storing hydrogen in a stratified salt geological context, particularly where pure rock salt and kainite interlayers are present. Finally, we explore the potential for a large-scale project, envisioning coexistence of traditional mining activities up to 200 m b.s.l. and hydrogen storage activities at greater depths (Units B and A) between 300 and 600 m.

How to cite: Anzelmo, G., Iacopini, D., Cella, G. M., Visconti, L., Edlmann, K., Cascone, M., Russo, G., Maniscalco, R., Parente, M., Sabatino, C., Di Benedetto, C., Colella, A., Balassone, G., Cappelletti, P., Cucciniello, C., Pappalardo, L., Di Clemente, E., Perrotta, L., Giovannelli, D., and Simili, M.: Integrated approach for hydrogen storage in a salt mine: the case of Realmonte, Sicily (Italy). , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9198, https://doi.org/10.5194/egusphere-egu24-9198, 2024.

EGU24-10197 | ECS | Orals | ERE3.1

A coupled discrete-continuum approach to simulating CO2 migration and dissolution in porous media  

Nicholas Ashmore, Ian Molnar, Stuart Gilfillan, and Magdalena Krol

Carbon capture and storage (CCS) has emerged as a principal emissions reduction technology for the energy transition. Its effectiveness hinges largely on the security of the storage reservoir, which may be susceptible to leakage through permeable pathways such as abandoned wells and faults. Storage failure presents risks of environmental impacts, increases in atmospheric carbon emissions, reduces both the value of carbon credits and public confidence in CCS as a viable technology for the energy transition. Given the importance of storage security, our understanding of CO2 leakage and its fate and transport in overburden must be improved to help in the prediction, detection and assessment of leaks. Shallow groundwater monitoring for dissolved gases can be complicated by multicomponent mass transfer dynamics in the subsurface. As CO2 migrates through the subsurface, much of the mass will partition from the gaseous to the aqueous phase, and conversely background dissolved gases present in groundwater such as N2 and O2 may partition to the gaseous phase, impacting both the evolution of dissolved gas concentrations and the persistence of free-phase gas in the subsurface. This process may also impact the performance of noble gas tracers in groundwater monitoring techniques. There is therefore a need for numerical models capable of accurately predicting the fate and transport of CO2 in the subsurface. However, traditional multiphase flow models struggle to describe the buoyant unstable gas flow regime expected at leak sites, dominated by gravity and capillary forces.

Unstable gas flow is characterized by discontinuous gas clusters and sharp variations in gas saturations in space, in contrast with the smooth variation in gas saturation predicted by continuum multiphase flow models. Discrete approaches such as macroscopic invasion percolation (MIP) are better equipped to model unstable gas flow, however they are limited by assumptions of instantaneous gas movement. ET-MIP (Electro-thermal MIP) is a general purpose model which couples continuum-based electrical, thermal, groundwater and chemical species modules with a discrete MIP gas flow module. This coupled approach allows for accurate simulation of slow gas displacement characteristic of shallow subsurface gas releases while simultaneously predicting the dissolution of CO2. ET-MIP has been validated against bench scale experiments and shown to accurately predict gas generation, multiphase transport and capillary trapping – all mechanisms which govern the fate of CO2 in the subsurface. This talk will present comparison of ET-MIP with a bench-scale CO2 injection and dissolution experiment and a sensitivity study showing the effects of key model parameters on CO2 migration. Findings highlight the benefits of using a discrete-continuum coupled approach for simulating CO2 migration in porous media, and the importance of considering background dissolved gases in the subsurface.

How to cite: Ashmore, N., Molnar, I., Gilfillan, S., and Krol, M.: A coupled discrete-continuum approach to simulating CO2 migration and dissolution in porous media , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10197, https://doi.org/10.5194/egusphere-egu24-10197, 2024.

EGU24-12575 | ECS | Posters on site | ERE3.1

Limestone reservoirs: are they good for CO2 geological storage? 

Dóra Cseresznyés, Nereo Preto, Katalin Báldi, Péter Kónya, Csilla Király, Orsolya Gelencsér, Ágnes Szamosfalvi, Csaba Szabó, György Czuppon, and György Falus

A promising method that could drastically reduce the effects of anthropogenic carbon-dioxide emissions is the capture of CO2 and its storage in geological formations (CCS technology). The processes that can take place in saline aquifers got under the spotlight in the last decades and the most promising options are sandstone reservoirs. However, natural CO2 trapped in carbonate (limestone) reservoirs are not well studied. The general assumption is that CO2 aggressively dissolves the limestone (matrix, grains, and cement), which would cause drastic changes in the reservoir properties (e.g., porosity, permeability).
To better understand the processes that CO2 injection can cause in a carbonate reservoir, a natural CO2 subsurface occurrence in Ölbő (Hungary) was investigated, where CO2 has been trapped safely in the limestone on a geological timescale. Core samples of the reservoir from 1700-1900 m depth were studied with various methods like petrography (carbonate facies analysis, nannoplankton determination), scanning electron microscopy, cathodoluminescence microscopy, X-ray diffraction and infrared spectroscopy. Microdrilling of the carbonates was also carried out to determine the C and O isotope composition of different constituents in order to reveal possible dissolution/recrystallization processes which may occur in the CO2 reservoir.
Two types of cement were found in the samples, a blocky, drusy cement and a syntaxial cement on the echinoderms (early cement). Contrary to the assumption, dissolution features, may be related to the CO2 inflow, were not observed in the rocks.
The average mineral composition of the samples is the following: 79 m/m% calcite; 6 m/m% dolomite; 3 m/m% ankerite, mica and quartz; 1 m/m% kaolinite, minor feldspar and pyrite. Dawsonite, the indicator mineral of CO2 flooding in siliciclastic sandstones, was not identified in the samples.
Carbonate components of the rock are Red algae, Foraminifera, Bryozoa, Bivalves, Echinoderms and Brachiopods. Nearly all were originally calcitic. Based on nannoplankton biostratigraphy and literature, the age of the host rock is Upper Badenian (Serrevallian), Middle Miocene.
The stable C and O isotope data of microfossils shows a narrow range, δ13C is ranging from -1.55‰ to 2.05‰ (average: -0.23‰), δ18O is between -7.98‰ to -0.25‰ (average: -4.54‰), expressed on the V-PDB scale. These data do not indicate the effect of magmatic CO2, which may reside in the Ölbő reservoir (Cseresznyés et al., 2021), in agreement with the petrography. According to our preliminary results, CO2 inflow did not affect the Ölbő limestone reservoir, i.e., did not imply significant dissolution, neither was involved in cement precipitation. Limestone thus could be an excellent physical trap for CO2. However, due to limited mineral reactions, our results indicate that limestone reservoirs may not be the best for mineral trapping which is the safest storage mechanism of CO2 on geological timescale. Further analyses will be carried out with geochemical modeling, to study the water-CO2-limestone reactions based on the Ölbő CO2 field.

Reference:
Cseresznyés et al 2021. ChemGeol.  https://doi.org/10.1016/j.chemgeo.2021.120536

How to cite: Cseresznyés, D., Preto, N., Báldi, K., Kónya, P., Király, C., Gelencsér, O., Szamosfalvi, Á., Szabó, C., Czuppon, G., and Falus, G.: Limestone reservoirs: are they good for CO2 geological storage?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12575, https://doi.org/10.5194/egusphere-egu24-12575, 2024.

EGU24-13643 | ECS | Orals | ERE3.1

Comparing fluid flow mechanisms in reservoir rocks to improve subsurface pollutant remediation 

Sandra Eriksson, James Minto, Katriona Edlmann, Gareth Johnson, Jennifer Roberts, and Zoe Shipton

In order to reach carbon neutrality, a drastic increase in subsurface carbon storage is essential. During the storge site selection process, sites are assessed based on overall security for long-term storage, and any remaining risks require a risk assessment with leakage mitigation plan. With an increase in large scale carbon storage, there is an increased chance of leakage and the potential for contamination of drinking water aquifers above the storage reservoir. In such a scenario, subsurface sweeping via the pumped injection of large volumes of water would be the most suitable method for remediation, yet this comes with issues of tailing and rebound occurring after the treatment has stopped, necessitating the injection of large volumes of water, over long time-scales, which significantly increases both the cost and carbon footprint of the remediation operation. With this study we look at how modified pumping techniques may improve sweeping to minimise rebound, but also how to minimise use of water.

The pumping techniques used in this study were continuous flow and pulsed flow. The pulsed flow was divided into two types, cyclic flow and rapid pulses. Cyclic flow has long breaks and relies on diffusion, whereas rapid pulses rely on vortices created in the pore spaces to increase mixing. The rock types used for the experiments were Clashach sandstone which represented a homogeneous rock, and Wattscliffe Lilac sandstone, representing a heterogeneous rock. The Clashach sandstone is quartz dominated and has a porosity of ca. 24 % with an overall uniform grain size and pore size, as well as well-connected pores. The Wattscliffe Lilac sandstone has a more heterogeneous mineralogy with a porosity of ca. 21 % and varied grain size, pore sizes, and pore connectivity. The different rock types were chosen based on their distinctly different pore structure to aid in understanding how heterogeneity impacts the different flow mechanisms. The cores were prepared at 4 cm long and just under 5 mm wide, covered in heat shrink tubing then cast in resin in order to prevent bypass flow, and optimised for pore-scale XCT imaging at injection pressures of up to 2 MPa. To study the recovery behaviour of the different flow types through the rock cores, fluorescein was used as a tracer and measured in a flow-through fluorometer. The resulting breakthrough curve, tailing, and total recovery was then used to determine which pumped flow method was the most efficient in terms of: 1) remediation of fluorescein, 2) water usage during remediation, and 3) speed of remediation. These different factors of efficiency can be crucial in determining which pumping method is used to remediate a contamination site.

How to cite: Eriksson, S., Minto, J., Edlmann, K., Johnson, G., Roberts, J., and Shipton, Z.: Comparing fluid flow mechanisms in reservoir rocks to improve subsurface pollutant remediation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13643, https://doi.org/10.5194/egusphere-egu24-13643, 2024.

Hydrogen is projected to account for at least 10% of the global energy system in 20 years and is a critical component of the future zero-emissions energy system. Underground storage of green hydrogen in Aotearoa New Zealand (ANZ) will take advantage of intermittent surplus of renewable electricity at low cost, balance seasonal fluctuations in energy supply and demand, and provide a strategic reserve of energy. This poster is part of a larger research programme primarily focused on investigating the potential for underground hydrogen storage (UHS) in Taranaki, ANZ. Here, we explore the potential for UHS in porous rock formations of depleted gas reservoirs with particular focus on the role of seal integrity for storage. 

In this project the overarching goal is to improve understanding of whether mudstone seal strata have the potential to prevent leakage of hydrogen from Taranaki reservoirs. The primary focus is to characterise the geometries of fault and fracture systems in seal strata, their impact on its bulk permeability and to identify the pressure conditions required to promote the loss of seal integrity. In this poster we use Formation Micro Imagery (FMI) together with stratigraphic and fault/fracture mapping of core from petroleum wells to identify fracture densities, orientations and properties in both seal and reservoir rocks. Interpretations of seismic reflection lines in Taranaki and analogous outcrop observations are used to understand the geometries and permeability properties of fault zones. 

Preliminary results indicate that fractures are present in both reservoir and seal rocks. The densities of fractures increase with proximity to regional fold hinges and faults, and with increasing carbonate content. Questions remain about under what conditions fractures are open and capable of transmitting hydrogen. The poster outlines preliminary results, proposed research pathways and invites discussion.

How to cite: Yates, E., Nicol, A., Parker, M., and Dempsey, D.: Impact of faults and fractures in mudstone seal rocks of porous-media underground hydrogen storage reservoirs – Case study in Taranaki, New Zealand, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13687, https://doi.org/10.5194/egusphere-egu24-13687, 2024.

EGU24-13837 | Orals | ERE3.1

Localized episodic deformation events in mudstone suggest limited pathways for gas breakthrough 

Hiroki Goto, Tomochika Tokunaga, and Masaatsu Aichi

Understanding the deformation behavior of mudstones induced by gas invasion is important to discuss the mechanical response of cap rock for geological sequestration of carbon dioxide (CO2), especially for evaluating possible CO2 leakage through cap rock. In this study, gas injection experiments were conducted by using a water-saturated mudstone core sample under relatively low excess gas pressure conditions, and the observed strain behaviors were compared between experiments with and without continuous gas invasion to identify characteristic deformation signals associated with gas invasion. In the experiments, the lateral surface of the sample was sealed with silicone rubber, then, the confining pressure was maintained to be 0.50 MPa and the pore water pressure to be 0.20 MPa as an initial condition. The air pressure was applied at the bottom of the sample, and was increased stepwise from 0.25 to 0.40 MPa with 0.05 MPa increments. Each condition was kept until a steady-state condition was achieved. Axial and circumferential strains at half the height of the sample were monitored using four cross gauges, and water discharge at the sample top was also observed. The measured water discharge indicated a very small amount of air invasion at the bottom air pressures of 0.25, 0.30, and 0.35 MPa, with eventual cessation of invasion. Notably, at 0.35 MPa, gas invasion persisted for a longer duration compared to the other two pressure conditions. At 0.40 MPa, the water discharge increased, and air breakthrough was observed. The measured cumulative water discharge at air breakthrough divided by the sample pore volume was 1%, indicating very limited air pathways in the sample. Under the condition that the bottom air pressure was 0.30 MPa or less, the measured strains showed initial possible poroelastic induced axial contraction and gradual extension, followed by gradual contraction, reaching to a steady-state condition. In the case where the bottom air pressure was 0.35 MPa or higher, early-stage strain behavior was similar, however, from the middle stage of the contraction phase, the strains showed a number of episodic sudden extensions and subsequent gradual contractions. Furthermore, the magnitude of the extensions differed significantly from gauge to gauge, and two of the gauges showed no extension. The observed localized episodic strain behaviors are attributed to air migration through limited pathways. When air invaded into part of the pore network filled with water, pore water pressure increased locally nearby the invaded pore, which should be close to the capillary pressure of the invaded pore. Strain gauges closer to the invaded pore then showed sudden extension and subsequent gradual contraction due to pore water pressure diffusion, while no strain was detected by other gauges located far from the invaded pore. The localized episodic sudden extensions followed by gradual contractions observed in our study strongly suggest very limited pathways for gas breakthrough in mudstones.

How to cite: Goto, H., Tokunaga, T., and Aichi, M.: Localized episodic deformation events in mudstone suggest limited pathways for gas breakthrough, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13837, https://doi.org/10.5194/egusphere-egu24-13837, 2024.

EGU24-14418 | Posters on site | ERE3.1

Hydrogen-driven microbial redox reactions in deep geosystems relevant for H2 storage 

Martin Krueger and Anja Dohrmann

In the subsurface, biotic and abiotic processes can generate and consume hydrogen. Hydrogen has a low reduction potential and is thus a highly energetic electron donor when involved in sulfate, carbon dioxide or ferric iron reduction. Although known as important drivers for the deep biosphere, the contributions of different processes to hydrogen turnover in different geosystems still are not well understood. In context with the ongoing transformation to renewable energy resources, underground H2 storage (UHS) in deep porous or salt cavern systems came into focus. In situ microbial and geochemical reactions that consume H2 are highly relevant topics in deep biosphere research, and also are still a major uncertainty during UHS.

Consequently, we studied the potential microbial hydrogen oxidation rates – combined with the possible production of metabolic products like H2S, acetic acid or CH4 - in formation fluids from natural gas fields and salt caverns, thereby considering the importance of in situ pressure and temperature conditions, fluid chemistry and mineral composition. In addition, more defined experiments were conducted with selected pure cultures representing important metabolic groups of deep biosphere microorganisms.

Several original formation fluids showed immediate H2 consumption. Microorganisms oxidized hydrogen at relevant in situ pressure conditions (up to 100 bar) and tolerated dynamically changing pressure and temperature conditions. The microbial hydrogen oxidation rate was strongly dependent on H2 partial pressures and the availability of e.g. sulfate as a terminal electron acceptor. High-throughput sequencing of 16S rRNA gene amplicons indicated hydrogen oxidation by sulfate reducing bacteria to be the presumed process in the studied porous rock reservoir fluids. In addition, hydrogen turnover by methanogenic and acetogenic as well as iron-reducing microorganisms was investigated. Also, the importance of biotic reactions in relation to abiotic hydrogen turnover processes at mineral surfaces will be discussed.

 

How to cite: Krueger, M. and Dohrmann, A.: Hydrogen-driven microbial redox reactions in deep geosystems relevant for H2 storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14418, https://doi.org/10.5194/egusphere-egu24-14418, 2024.

EGU24-14723 | ECS | Orals | ERE3.1

Reevaluating seismic hazard and ground motions for North Sea CO2 storage projects 

Chen Huang, Brian Carlton, Tom Kettlety, Tine Larsen, J. Michael Kendall, and Elin Skurveit

The North Sea plays a strategic role in the transition towards the green economy, as it hosts many offshore wind farms and carbon capture and storage (CCS) sites. The North Sea is characterized by moderate seismicity. For example, the 2023 Mw 5.1 North Sea earthquake was the largest earthquake in the region in 33 years, and led to a temporary shutdown of production of Equinor’s oil platform Snorre B.

The last comprehensive seismic hazard assessment of the North Sea was performed about twenty years ago (Bungum et al. 2000). Since then, there have been many new ground motions recorded from both onshore and offshore seismic stations in the North Sea region, as well as major advancements in probabilistic seismic hazard assessment (PSHA) methodology. As a result, this study aims to develop the first region-specific ground-motion model for the North Sea, which will be used in an updated PSHA to ensure the safe design of new offshore wind farms and CCS sites.

This research forms a part of the SHARP-Storage project, an interdisciplinary Accelerating CCS Technologies project developing improved methods for quantitative assessment of subsurface CO2 storage containment risks. The SHARP project compiled a dataset of North Sea ground-motion records, which comprises data on natural seismicity from broadband seismometers, both onshore and offshore. Moreover, synthetic ground motions are generated to address the paucity of recordings (especially strong motions) in the North Sea region. The associated flat-file, including the metadata and intensity measures (e.g., spectral acceleration and Fourier amplitude) of manually processed waveforms is constructed for the analysis of the ground motion characteristics in the North Sea. An empirical ground-motion model is developed based on the recorded and synthetic data, which is validated and compared with the available observations and models for the North Sea.

The ground-motion model is defined for a reference rock condition. Amplification factors to estimate shaking at the soil surface are derived based on a database of one-dimensional site response analyses. The sediments encountered in the North Sea have been deposited in dynamically changing environments ranging from arctic to temperate and reworked by the movement of ice sheets. As a result, a wide range of soil types and properties are found. To capture this variability, representative profiles are developed based on site investigations from locations with different soil conditions encountered in the North Sea. One dimensional non-linear site response analyses are then performed using the recorded and synthetic ground motion database to generate a database of response spectra amplification values.

This study presents the preliminary results of the North Sea ground-motion model and highlights the challenges in conducting PSHA for the North Sea region. These results improve the assessment of seismic hazard and risks to CO2 storage security in the North Sea.

How to cite: Huang, C., Carlton, B., Kettlety, T., Larsen, T., Kendall, J. M., and Skurveit, E.: Reevaluating seismic hazard and ground motions for North Sea CO2 storage projects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14723, https://doi.org/10.5194/egusphere-egu24-14723, 2024.

EGU24-14800 | ECS | Posters on site | ERE3.1

Numerical Modeling of Fluid Flow through a Borehole-Porous Medium System: Comparison between Brinkman and Darcy Equations 

Joseph Regur, Jiaqi Liu, and Tomochika Tokunaga

Subsurface petroleum storage in excavated caverns sealed using a hydraulic containment system offers many advantages over traditional surface storage tanks. The challenge of accurately simulating a complex subsurface system includes accounting for the viscous shear forces within free-flow regions such as the boreholes, fractures, voids, and storage tanks. The Brinkman extended Darcy’s equation is one solution which accounts for viscous shear forces along the free-flow boundaries and momentum transfer across the porous media interface.

This study aims to demonstrate the significance of fluid viscosity forces in the subsurface flow regime, and show the suitability of the Brinkman equation by using numerical modeling in COMSOL to create lab-scale simulations of a borehole coupled with porous media. It analyzes and compares the simulated velocity gradients and head gradients, calculated using the Brinkman equation and the classic Darcy equation. This study shows simulation cases at various inlet pressures, inlet velocities, porosities, and permeabilities, such as those used for subsurface storage to evaluate the influence of these parameters.

The preliminary results show that the Brinkman equation predicts a non-uniform velocity profile within the borehole due to friction along the borehole interface. The two equations also predict  different velocity distributions across the borehole interface and in the porous media near the borehole. These differences are more significant at higher inlet velocities/pressures. These models could be validated by laboratory experiments, enhanced to include fractures, and enlarged to field scales. This study will have implications for numerous injection and well production activities, such as subsurface energy storage, hydraulic fracturing, and contaminant transport studies.

How to cite: Regur, J., Liu, J., and Tokunaga, T.: Numerical Modeling of Fluid Flow through a Borehole-Porous Medium System: Comparison between Brinkman and Darcy Equations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14800, https://doi.org/10.5194/egusphere-egu24-14800, 2024.

EGU24-15010 | Orals | ERE3.1

Impact of CO2 with impurities on integrity of wellbore cements during CCS  

Reinier van Noort and Gaute Svenningsen

CO2 injected into geological reservoirs for storage will contain a range of impurities dependent on the specifications of the transport and storage operator(s). Such impurities include inert gases such as N2 and Ar, as well as reactive components including SOx, O2, and H2S. Upon injection into a (wet) reservoir, these components will partition between the CO2-phase and the hydrous pore fluid, and some of the reactive species may introduce acidification (in addition to the acidification caused by the CO2 itself), or other chemical reactions. 

In the near-wellbore area, the partitioning impurities can potentially lead to enrichment of water-soluble impurities in the hydrous fluid and corresponding depletion of these impurities in the CO2 plume. Because of this, even low (ppm-level) concentrations of reactive impurities need to be considered with regards to their potential impact on wellbore sealant integrity. As part of the Cementegrity project, we have performed exposure experiments on five different sealant compositions; three of which are based on Ordinary Portland Cement (OPC), one is based on Calcium-Aluminate Cement (CAC) and one is a granite-based geopolymer (GP). Using a purpose-built batch-exposure system, sample cylinders were exposed to water and supercritical CO2 under simulated downhole conditions of 80°C and 8-10 MPa, for up to 16 weeks. The sealant samples were placed at two different levels in each exposure apparatus, so that samples were either exposed to wet supercritical CO2, or to CO2-saturated water. The effect of H2S in the CO2 stream was studied in a second series of experiments, where 2.2 mol% H2S was added to the CO2-phase to which the samples were exposed.

After exposure, the samples were retrieved and cross-sectioned perpendicular to the axial direction, so that the impact of exposure on sealant microstructure and composition could be studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). In this paper, we will focus on the different impacts of exposure conditions (wet sc. CO2 vs. CO2-saturated water) as well as the additional impact of H2S.

How to cite: van Noort, R. and Svenningsen, G.: Impact of CO2 with impurities on integrity of wellbore cements during CCS , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15010, https://doi.org/10.5194/egusphere-egu24-15010, 2024.

Large-scale carbon capture and storage (CCS) stands a crucial role in achieving net-zero emissions by 2050. To successfully deploy the geological CO2 storage, it is essential to consider heterogeneities of storage reservoirs and surrounding strata. The variation of porosity, permeability, relative permeability, and capillary pressure have a significant influence on storage capacity, potential leakage, CO2 plume migration, and risk assessment. Besides, underground aqueous CO2 can convert to minerals or form insoluble ionic species if reacting with specific ions or solid minerals. These processes, known as geochemical trapping, is considered as the most permanent form of storage.

In this work, we utilize the well-known multiphase flow software TOUGH3 as well as reactive-transport software TOUGHREACT with module ECO2N, to simulate the behavior of CO2 injected into the 2D large-scale models comprising aquifer, seal, and reservoir layers with homogeneous distributions.  A series of sensitivity studies on porosity-permeability relations, different pairs of relative permeabilities and different heterogeneous distributions generated from a geostatistical software SGeMS will be conducted in this work to investigate their impacts on CO2 plume migration and pressure evolutions.  In addition, capillary trapping mechanisms are also simulated based on sensitivity studies on different capillary pressure curves. Finally, brine with different concentration species is considered to simulate the geochemical trapping.

This research aims to achieve the following objectives: 1. Examine the impact of uncertainties of petrophysical properties and heterogeneities. 2. Analyze preliminary results of predicted pressure buildup and saturation distribution in the heterogeneous models. 3. Evaluate the possible storage capacity of both physical and geochemical trapping.

How to cite: Kung, C.-E., Kuo, C.-W., and Yang, Y.-C.: Numerical Simulation of CO2 Storage Behavior: Investigation of Physical and Geochemical Trapping in Heterogeneous Underground Structures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15218, https://doi.org/10.5194/egusphere-egu24-15218, 2024.

EGU24-15536 | ECS | Posters on site | ERE3.1

Mineral reactivity under subsurface hydrogen storage conditions from the Carpathian-Pannonian region: an experimental and geochemical modeling study 

Orsolya Gelencsér, Csaba Árvai, László Mika, Ákos Kővágó, Dóra Cseresznyés, Csaba Szabó, Péter Tóth, Dániel Breitner, Zsuzsanna Szabó-Krausz, and György Falus

The concept of subsurface hydrogen storage was born in the middle of the 1970’s in the shadow of the global oil crisis, however the high prices of commercial hydrogen limited the interest in it as an energy source. Today, hydrogen is considered to be a major energy carrier as well as potential alternative fuel in transportation.

Porous rocks receive a high attention for the future hydrogen storage as geologic structures can achieve greater void volume compared to surface storage options. Understanding the potential reactions of injected hydrogen with pre-existing minerals, gases, ions, and other substances (e.g., microorganisms) is critical as it is required for safety and keeping the quality of the withdrawn hydrogen. Abiotic processes are inorganic reactions between the reservoir rock, in-situ brine, and injected H2 that could alter the petrophysical reservoir performance (porosity, permeability, pore structure, and composition) and the geo-mechanical stability of the rock.

The subject of this research is the Late Miocene sandstone of the Alföld Formation Group located in the Pannonian basin, Carpathian-Pannonian region. This succession can potentially play a significant role in hydrogen storage in the future, due to its favorable reservoir geological and petrophysical characteristics.

We studied the abiotic reactions that can occur in the reservoir by a combined experimental and geochemical modeling work. Among the rock forming minerals, two constituents are highlighted in this study. K-feldspar (KAlSi3O8) is one of the most pH sensitive silicate minerals and pyrite (FeS2) is a redox sensitive accessory mineral of sedimentary rocks.

Static batch reactor experiments were conducted in the pressure and temperature range of subsurface hydrogen storage to track the effect of hydrogen on K-feldspar and pyrite in a similar way as described in Gelencsér et al. (2023). Geochemical modeling was performed in PHREEQC modeling environment.

Results show that K-feldspar behaves similarly both under hydrogen and nitrogen “atmosphere”. Pyrite can react with hydrogen resulting in partial alteration of pyrite surface (thorough the precipitation of pyrrhotite [FeS]) and hydrogen sulfide (H2S) production, whereas the reference experiments (with nitrogen) did not show any H2S release or the appearance of pyrrhotite.

 

Project no. 971238 has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund, financed under the KDP-2020 funding scheme.

 

Reference:

Gelencsér O., Árvai C., Mika L. T., Breitner D., LeClair D., Szabó C., Falus G. and Szabó-Krausz Z. (2023) Effect of hydrogen on calcite reactivity in sandstone reservoirs: Experimental results compared to geochemical modeling predictions. J. Energy Storage 61, 1–6.

How to cite: Gelencsér, O., Árvai, C., Mika, L., Kővágó, Á., Cseresznyés, D., Szabó, C., Tóth, P., Breitner, D., Szabó-Krausz, Z., and Falus, G.: Mineral reactivity under subsurface hydrogen storage conditions from the Carpathian-Pannonian region: an experimental and geochemical modeling study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15536, https://doi.org/10.5194/egusphere-egu24-15536, 2024.

EGU24-17893 | ECS | Orals | ERE3.1

Reservoir and seal characterization of deep marine sediments using seismic facies analysis with machine learning techniques 

Tural Feyzullayev, David Lubo-Robles, Beatriz Benjumea, Heather Bedle, Estefanía Llave, Francisco Javier Hernández-Molina, and Zhi Lin Ng

This work describes key aspects of the methodology for subsurface characterization of Late Miocene deep marine sedimentary systems of the Gulf of Cádiz. In particular, we focus on the products of alongslope bottom currents processes, known as contourite systems, and mixed deposits developed by the interaction between contourite and downslope turbidite systems. Both these systems offer prospects for CO2 storage for their high reservoir potentials. In addition, hemipelagic sediments and fine-grained contourites present in the area could act as seals. The objective of this study consists of using seismic attributes and machine learning techniques for conducting a seismic facies analysis to distinguish between various Late Miocene deep marine deposits in a 3D seismic volume. The first step is to restrict the dataset to the deposits of interest in order to avoid irrelevant sediments or structures such as the allochthonous unit of the Gulf of Cádiz or salt domes or diapirs. This adjusts the dynamic range of the clustering to focus on our targets. The second step is the testing of the seismic attributes to improve their selection criteria, in order to maximize the differences between the distinct seismic facies. Finally, we apply an unsupervised clustering algorithm for the selected seismic attributes to perform an automatic seismic facies analysis that facilitates both reservoir and seal imaging. This study will ultimately help to assess the socio-economic impact of Late Miocene sediments developed by bottom currents on climate change mitigation and energy transition. This research and the Grant PRE2022-102745 were funded by MCIN/ AEI/10.13039/501100011033 and they are linked to the ALGEMAR project (PID2021-123825OB-I00). This work is partly supported by SEASTORAGE project (TED2021-129816B-I00), funded by MCIN/ AEI/10.13039/501100011033/PRTR-C21 and by the European Union NextGenerationEU.

How to cite: Feyzullayev, T., Lubo-Robles, D., Benjumea, B., Bedle, H., Llave, E., Javier Hernández-Molina, F., and Lin Ng, Z.: Reservoir and seal characterization of deep marine sediments using seismic facies analysis with machine learning techniques, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17893, https://doi.org/10.5194/egusphere-egu24-17893, 2024.

EGU24-18106 | ECS | Orals | ERE3.1

Exploiting induced carbonate precipitation to improve reservoir storage integrity and geothermal system efficiency 

Philip Salter, Katherine Dobson, James Minto, and Jay Warnett

Biomineralization, through microbially, thermally, or enzyme induced carbonate precipitation (MICP/TICP/EICP), is a cost-effective cementation process for changing porosity and permeability in the subsurface. This study aims to optimize compositional and injection parameters for biomineralization fluids, and to develop understanding of the interactions between geochemical reactions and fluid transport properties at the pore (micron) scale. Utilizing real-time in situ X-ray computed tomography (XCT), we compare traditional Microbially Induced Calcium Carbonate Precipitation (MICP) with novel thermally delayed (TICP) and Enzyme Induced Calcium Carbonate Precipitation (EICP) in a range of lithologies. This allows us to investigate the impact of mineralogy, grain size distribution, and temperature as well as the injection composition and strategy. We present quantitative analysis of crystal locations, the volume of carbonate and of individual crystals, and the effect of crystals on permeability and flow localisation over time. Coupled to measured changes in microstructural and macroscopic properties over repeated precipitation and dissolution cycles we present refined models of reactive transport for different injection strategies, and identify the optimal treatment strategy for different subsurface applications. This includes validation of the durability of precipitated calcite seals during dissolution phase, simulating the behaviour of CO2-enriched brines.

This work provides the underpinning understanding principles of crystal formation, growth and hydrodynamic feedback mechanisms necessary for accurate modelling of reservoir scale dynamic processes.  However, we also show how TICP and EICP strategies can improve performance of real-world Carbon Capture and Storage systems, driving more homogeneous, widely distributed and larger volumes of precipitated CaCO3 by maintaining permeability during treatment at higher degrees of cementation when compared to MICP. We also show how variable injection strategies allow improvement of other physical properties (e.g. mechanical strength) and enables the addition of highly conductive additives or phase change materials without reducing precipitation and flow. Using CaCO3 precipitation we observed a 470% increase in the thermal conductivity of unsaturated quartz sand after 9 cycles of MICP, and an 800% increase following addition of 5 wt% expanded natural graphite (ENG). Our findings also demonstrate the compatibility of integrating paraffin as a phase-change material within the porous matrix of ENG prior to MICP/EICP treatment significantly increasing specific heat capacity. These new geomaterials have widespread implications for thermal energy storage, specialized geothermal grouts/backfill, shallower wells and reduced geothermal energy costs.

The project's outcomes impact the commercialization of engineered biomineralization and its role in the subsurface energy transition.

How to cite: Salter, P., Dobson, K., Minto, J., and Warnett, J.: Exploiting induced carbonate precipitation to improve reservoir storage integrity and geothermal system efficiency, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18106, https://doi.org/10.5194/egusphere-egu24-18106, 2024.

EGU24-18221 | ECS | Orals | ERE3.1

An analytical tool for estimating fault slip probability for CO2 storage resources under pressure constraints  

Iman R. Kivi, Silvia De Simone, and Samuel Krevor

The majority of pathways toward net-zero CO2 emissions propose carbon capture and storage (CCS) at rates of several gigatonnes per year by mid-century. However, there are limits on the rates at which storage resources can be used. In addition to the total storage resource, constraints are imposed by reservoir injectivity and the possibility of triggering large earthquakes by injection-induced overpressure. Such dynamic constraints are rarely considered in the assessments of available resources and possible CCS deployment rates. In this work, we have extended an open-source tool, named CO2BLOCK, from calculating reservoir pressurization during CO2 injection to additionally estimating the probability of fault slip in the region. This provides a computationally efficient methodology for screening dynamic CO2 storage resources. The code features a deterministic hydrogeology module that employs analytical solutions of radial, multiphase flow for a single site with time-varying injection rates and the superposition principle to calculate the spatiotemporal evolution of pore pressure in multisite, basin-scale injection scenarios. The calculated overpressure is used to analyze the slip tendency of the faults imported or randomly distributed across the basin. A probabilistic geomechanical module runs Monte-Carlo simulations to generate cumulative distribution functions of slip probability as a function of pore pressure changes for each fault from statistical ensembles of uncertain parameters including the state of stress and fault attributes and frictional strength. A combination of the two modules yields the evolution of fault slip probability as a function of time through the project life. The proposed approach allows for optimizing large-scale CCS project designs for the number and spacing of injection sites to return maximum storage rates and capacities while maintaining the risk of induced seismicity at a low level. The application of CO2BLOCK could assist in developing more realistic representations of CCS scale-up potential and the subsurface resource use in different climate change mitigation pathways. 

How to cite: Kivi, I. R., De Simone, S., and Krevor, S.: An analytical tool for estimating fault slip probability for CO2 storage resources under pressure constraints , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18221, https://doi.org/10.5194/egusphere-egu24-18221, 2024.

EGU24-18572 | ECS | Posters on site | ERE3.1

Cushion Gas Type and Optimal Volume for Underground Hydrocarbon Storage in a Depleted Gas Reservoir in the Celtic Sea 

Solmaz Abedi, Niklas Heinemann, Arthur Satterley, Carolina Coll, and Philippa Park

Transitioning to renewable energy is crucial for combating climate change, but solar and wind power face supply-demand gaps due to seasonal dependencies. To bridge this gap, converting excess renewable energy into hydrogen for storage in depleted onshore and offshore gas fields offers a promising solution, enabling stored energy for use during high-demand periods without carbon emissions. These sites offer an attractive option for underground hydrogen storage, facilitating global distribution and using existing infrastructure.

However, selecting the type and required optimum volume of cushion gas is crucial to ensure the effective reproduction of working gas and economic feasibility. To address this, an analogue model was built based on the geology of the Kinsale field, a depleted gas field potential future hydrogen store in the Celtic Sea. This model uses reservoir and flow properties derived from wireline data of existing wells and the geological system in the area.

For fluid flow, a compositional simulator was used to model changes in fluid composition. Actual field operational control parameters such as maximum and minimum pressure ranges were considered. A uniform depletion procedure was initiated reflecting current field production data. The study investigated the impact of various aspects of the hydrogen storage operation, including reservoir heterogenity, number of wells, cushion gas types, and optimal scenarios for working gas production.

The findings reveal that after the first storage cycle, injecting hydrogen as a cushion gas yields the highest purity (93.5%) of produced hydrogen working gas, while methane as a cushion gas exhibits the lowest purity (85.2%). The hydrogen purity increases with increasing cycles, but 100% purity cannot be achieved because of the in-situ natural gas. Moreover, across production phases, the hydrogen purity in the produced gas within each cycle declines over time. This decline is attributed to decreasing pressure during production leading to the migration of methane from the surrounding flanks toward the wellbore area.  Additionally, an increase in the number of wells decreases the required volume of cushion gas because multiple wells require lower production pressures to produce the same volume of stored gas.

Based on the findings derived from the simulations, we conclude that depleted natural gas reservoirs offer a viable option for hydrogen storage in terms of both dynamic storage capacity and hydrogen purity.

How to cite: Abedi, S., Heinemann, N., Satterley, A., Coll, C., and Park, P.: Cushion Gas Type and Optimal Volume for Underground Hydrocarbon Storage in a Depleted Gas Reservoir in the Celtic Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18572, https://doi.org/10.5194/egusphere-egu24-18572, 2024.

To achieve a carbon-free economy in the medium term, hydrogen has been proposed as a viable solution. This requires large-scale subsurface storage options, especially, if green hydrogen produced from fluctuating renewable energy sources like wind and solar energy is considered. While H2 has already been stored successfully in salt caverns for decades, H2 storage in porous media like hydrocarbon-depleted reservoirs and saline aquifers still requires further research. We use an almost depleted gas reservoir in northwestern Germany to test various scenarios regarding withdrawal/injection cycles and different cushion gases. The case study field presents a faulted reservoir in a highly fractured rock of Upper Permian (Zechstein) age, consisting mainly of dolomite as reservoir rock and anhydrite as cap rock. A history-matched dynamic model starting in 1959 of a gas-depleted reservoir calibrated from the comprehensive information available for the reservoir site, such as density, viscosity, relative permeability, and capillary pressure, which serves as a hypothetical base case for seasonal hydrogen storage, intending to store around 300 Mio sm3. An isothermal compositional reservoir simulator with seven components is used including H2S to monitor its concentration. Eight prediction cases were simulated, excluding: diffusion, dispersion, and microbial reaction. Between each case, changes are made to the type and amount of cushion gas injected following the same injection/withdrawal cycle, mixing the cushion gas between N2+CH4, H2+N2, H2+CH4, H2+CO2, pure CH4, pure CO2, pure N2, and pure H2. Following an initial filling from only the cushion gas of 33-months of around 730000 (sm3/d). Immediately after, withdrawal begins for 2 months from the working gas of around 3600000 (sm3/d) and withdrawal/injection cycles for 3(W)/6(I) months were the amount of working gas injected increases to 1800000 (sm3/d), and with a shut-down phase for 1 month after withdrawal and 2 months after injection, for 7 times; resulting in a total H2 production over 8 cycles. The applied amounts were to avoid any spilling due to the highly-fracture nature of the reservoir. In a subsequent simulation from the case of using pure N2, the prediction time was increased to observe its changes over the next 7 years. To assess the overall recovery of hydrogen and the concentration of H2S, a volumetric and molar storage balance was analyzed. Based on the results of all the 8 simulations, at least on the first four cycles, less H2 is recovered, except if pure H2 is injected from the beginning as a filling phase. Despite this, all simulations show a greater H2 recovery for the last cycle, from 96% (pure N2 as cushion gas) to 99% (pure H2 as cushion gas). Regarding H2S, shows a diluted concentration while the storage cycles are increased, resulting lower than 2x10-5 mole fraction for the last cycle. A longer time prediction reveals that H2 recovery for the last cycle can nearly reach 100%. The next steps involve realizing a thermal simulation for the observation of the temperature effect and how can it effect the storage process, and a preliminary economic study of the storage site to determine its feasibility.

How to cite: von Reinicke Laredo, D. A.: Reservoir simulation studies in underground hydrogen storage in a depleted gas reservoir - northwestern Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18645, https://doi.org/10.5194/egusphere-egu24-18645, 2024.

EGU24-18771 | ECS | Orals | ERE3.1

Experimental investigation of hydrogen flow behavior in porous media at reservoir conditions. 

Wisdom David, Juliane Kummerow, Mrityunjay Singh, Conny Schmidt-Hattenberger, and Ingo Sass

Hydrogen (H2) is a clean source of energy and a promising solution in the energy transition due to its vast energy content and potential of zero greenhouse gas emissions. Storing hydrogen to meet present and future energy demands requires a large storage volume which is only available in subsurface reservoirs such as salt caverns, depleted oil and gas fields, and deep saline aquifers. Despite the high demand for Underground Hydrogen Storage (UHS) technology as part of a full H2-value chain, there is especially limited knowledge of the transport behavior of hydrogen in porous media [1]. With its charging and discharging operations, the storage of hydrogen in a porous reservoir formation undergoes a transient flow process, influenced by coupled thermo-hydro-mechanical processes between hydrogen, the formation fluid, the solid components of the rock, and the prevailing temperature and pressure regime, which repetitively changes under geotechnical utilization [2]. In consequence of cyclic storage operations, variations in effective mechanical stresses can affect the pore space geometry and may lead to irreversible deformation and weakening of reservoir and cap rocks.
Here, we present first results of an experimental laboratory study focussing on fluid substitution experiments (gas replacing brine) on various sandstone core samples sourced from Bad Bentheim and the Stuttgart formation. The study was specifically designed to replicate the unique reservoir conditions of the Stuttgart formation at the Ketzin site in Germany (confining pressure = 150 bar, pore pressure = 25 to 75 bar, temperature = 37 °C). In the frame of the national-funded GEOZeit project, long-term flow experiments are carried out to determine  the evolution of relative permeability of H2-brine and CH4-brine systems in dependence of the number of load cycles. Alongside, measurements of electrical resistivity and ultrasonic wave velocities at each brine/gas saturation state are performed. This enable us to derive the saturation level and to understand the spatial distribution of liquid and gaseous phases in the pore space of our sample material. The experiments are complemented by a range of additional tests, including chemical analyses and microstructural investigations using XRD, SEM, and optical microscopy. Our results are expected to improve the understanding of coupled hydromechanical processes and their impact on reservoir properties during geotechnical operations, and to also provide the necessary parameters for large-scale modelling and up-scaling, required to assess the feasibility of storage, production, and monitoring of hydrogen gas in porous geological formations.

[1] Heinemann, N., Alcalde, J., Miocic, J. M., Hangx, S. J. T., Kallmeyer, J., Ostertag-Henning, C., Strobel, G. J., Hassanpouryouzbanda, A., Schmidt-Hattenberger, C., Edlmann, K., Wilkinson, M., Thaysen, E. M., Bentham, M., Haszeldine, R. S., Carbonell, R., Rudloff, A. (2021). Enabling large-scale hydrogen storage in porous media – The scientific challenges. Energy & Environmental Science, 14(2), 853–864. https://doi.org/10.1039/D0EE03536J


[2] Ershadnia, R., Singh, M., Mahmoodpour, S., Meyal, A., Moeini, F., Hosseini, S. A., Sturmer, D. M., Rasoulzadeh, M., Dai, Z., Soltanian, M. R. (2023). Impact of geological and operational conditions on underground hydrogen storage. International Journal of Hydrogen Energy, 48 (4), 1450-1471. https://doi.org/10.1016/j.ijhydene.2022.09.208.

How to cite: David, W., Kummerow, J., Singh, M., Schmidt-Hattenberger, C., and Sass, I.: Experimental investigation of hydrogen flow behavior in porous media at reservoir conditions., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18771, https://doi.org/10.5194/egusphere-egu24-18771, 2024.

Capturing large quantities of CO2 from the atmosphere and sequestering voluminous amounts into deep saline aquifers form one of the key aspects of modern-day climate change mitigation strategies. However, the technical challenge lies in understanding the non-linear dynamics which govern the flow and transport of CO2 in the subsurface. Diffusion of CO2 into brine causes the development and growth of a diffusive layer having a density greater than the ambient brine. This layer yields to small scale perturbations in the flow field thereby producing fingers which propagate with time, facilitating dissolution and trapping. In natural systems, the solubility of CO2 and the mixing behavior is influenced largely by the simultaneous impact of ambient pressure, temperature, brine salinity, heterogeneity and background flow. Although, previous studies have mainly investigated fingering dynamics for homogeneous and heterogeneous cases, employing little or no background flow, a full-scale study collectively considering the different parameters remains to be done.  

For our research we developed a 2D particle tracking reservoir simulator to model the transport dynamics of single-phase CO2-brine mixture for a system with spatially varying density, viscosity and local diffusion coefficient, governed primarily by variations in salinity and mixture concentration. Using this simulator, we perform a large-scale Monte Carlo parametric study to establish a thorough understanding regarding the influence of heterogeneous permeability-porosity fields, variable background flow, multicomponent electrolyte brine systems and dispersion anisotropy on the fingering dynamics and transport behavior of CO2-brine mixtures in the subsurface. We will demonstrate how salinity gradients in typical aquifers influence the viscosity and density variations of the mixture at wide ranges of reservoir heterogeneities and investigate its effect on the convective mechanism and mixing behavior. Additionally, in this regard, we will also examine how transverse shearing disrupts fingering thereby influencing the dissolution rate of CO2 into the aquifer. We will also present results highlighting fingering dynamics in preferential permeability pathways of aquifers having very high heterogeneities at different salinities and background flow. Finally, we will investigate how the interplay of these above physical parameters at different degrees affect the standard transition regime stages that are developed previously for homogeneous and heterogeneous cases. The novelty of study lies in considering a much wider range of attributes deemed important to influence large scale fingering dynamics and mixing behavior, where currently to our knowledge, no studies have been performed.

How to cite: Sen, S. and Hansen, S. K.: Understanding the effects of heterogeneity, salinity and background flow on convective dynamics of CO2-brine mixture in fully saturated porous media at geologic carbon storage conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19156, https://doi.org/10.5194/egusphere-egu24-19156, 2024.

Large scale storage of hydrogen in porous reservoirs can buffer intermittent energy supply and demand in energy systems with large contributions of wind and solar energy. The efficiency of long term injection and withdrawal of hydrogen streams with large concentrations of hydrogen can be particularly affected by the long term interaction between hydrogen and rock or well materials in combination with cyclic pressure, temperature and stress changes during injection and withdrawal. Critical elements of hydrogen storage systems that may be affected are (1) the hydrogen gas stream, (2) the storage reservoir, (3) the caprock, (4) faults, (5) the well system, and (6) the surface environment. In particular, effects on the durability and integrity of well systems and on the mechanical and flow properties of porous sandstone reservoirs may impact the efficiency of storage operations. In this study, we show how results of laboratory experiments on rock and well materials at high pressure and temperature conditions can be used to assess effects of hydrogen exposure and cyclic pressure, temperature and stress changes on well systems and porous sandstone storage reservoirs. Key results of experiments on well cement (Portland type G), sandstone reservoirs, caprock and a scaled-down well system consisting of a casing, well cement and reservoir rock are reported. Samples were placed under relevant high pressure, temperature and stress conditions (100-200 bar, 50-100°C), both in an autoclave for reaction with H­2 and N2 and in a triaxial cell for testing injection/withdrawal scenarios. The results show (1) no major effects of H2 exposure or cyclic loading on mechanical properties of well cement and reservoir sandstone under investigated conditions, (2) different behavior for sandstones exposed to N2 (stiffer) and H2 (less stiff) during cyclic loading, (3) some cumulative plastic deformation during cyclic loading of sandstone that may affect flow and mechanical properties, even in the elastic regime, (4) indications of increasing stiffness in caprock due to cyclic loading, (5) importance of casing-cement-reservoir interfaces as potential leakage pathways for hydrogen along wells, and (6) large effects of sample variations that complicate disentangling effects of N2/H2 exposure and cyclic loading. These results suggest that effects of interaction between hydrogen and rock or well materials in combination with cyclic pressure, temperature and stress changes during injection and withdrawal are limited for the investigated materials and conditions. However, they also emphasize the need for further research to understand the long-term effects of H2 exposure and cyclic loading in different geological settings and under extended exposure durations.

How to cite: ter Heege, J., Corina, A., Soustelle, V., and Groenenberg, R.: Durability and integrity of well and rock materials for large scale underground hydrogen storage projects in porous reservoir: Insights from laboratory experiments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19609, https://doi.org/10.5194/egusphere-egu24-19609, 2024.

EGU24-20803 | ECS | Posters on site | ERE3.1

Ostwald Ripening Leads to Less Hysteresis during Hydrogen Injection and Withdrawal: A Pore-Scale Imaging Study 

Sepideh Goodarzi, Branko Bijeljic, and Martin Blunt

We performed three cycles of hydrogen injection (drainage) followed by brine
injection (imbibition) combined with high-resolution three-dimensional X-ray imaging on a
sample of Bentheimer sandstone. After each injection, the sample was imaged initially and
after waiting 16 hours. Capillary pressure was measured from the differential pressure across
the rock once the injection has stopped and from estimating the meniscus curvatures from the
images. In addition, the gas saturation, pore occupancy, Euler characteristic and interfacial areas
were measured. There was a significant rearrangement of the gas in the pore space after injection stopped,
which we hypothesise is caused by Ostwald ripening, namely the transport of dissolved hy-
drogen in the aqueous phase to equilibriate local capillary pressure. This rearrangement led to
the formation of larger, more connected gas ganglia. The capillary pressure displayed char-
acteristics that cannot be explained by traditional hysteresis models. While the direct and
curvature-based measurements agreed to within experimental uncertainty, and corresponded to
independent measurements in the literature on initial displacement, Ostwald ripening allowed
less trapping and less hysteresis (a smaller difference between drainage and imbibiton capillary
pressure) than measured previously on mercury and oil/water systems where Ostwald ripening
did not occur. The results imply that for gas storage applications it is not appropriate to use hysteresis
measurements based on mercury or hydrocarbon systems. Instead, in local capillary equi-
librium, there is less trapping and less difference between drainage and imbibition capillary
pressure.

How to cite: Goodarzi, S., Bijeljic, B., and Blunt, M.: Ostwald Ripening Leads to Less Hysteresis during Hydrogen Injection and Withdrawal: A Pore-Scale Imaging Study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20803, https://doi.org/10.5194/egusphere-egu24-20803, 2024.

EGU24-1317 | Posters on site | ERE3.2

Geochemical profiles in the hydrogeological system of the Opalinus Clay 

Anja Schleicher, Marie Bonitz, Theresa Hennig, Jessica Stammeier, David Jaeggi, and Michael Kühn

Opalinus Clay is the chosen host rock for the deep geological disposal of nuclear waste in Switzerland and is also being considered for this purpose in Germany. For the long-term integrity of the disposal site, temporally and spatially stable geochemical conditions are essential. Adjacent aquifers can induce changes into the system. It is therefore essential to investigate if and how the geochemistry and mineralogy of the sediments is influenced by the hydrogeology. Changes in the Opalinus Clay and the surrounding formations provide information about geochemical processes in the past and thus enable an assessment for the future.

In this context, a 58 m long borehole was drilled at the Swiss Rock Laboratory in Mont Terri. Drilling was conducted from the Opalinus Clay (Toarcian) through the entire Staffelegg Formation (Toarcian-Sinemurian), which contains two water-bearing sections. The groundwater, the members and their transitions were characterised with a variety of analytical methods.

Groundwater was found locally in the Beggingen (Gryphaea Limestone) and Rietheim (Posidonia Shale) members, depending on the presence of pathways in open fractures and with differences in their chemical composition. The groundwater in the Rietheim member is not directly connected to the surface, but seems to be continuously recharged by an adjacent aquifer. At the transition from the Gross Wolf to the Rietheim Member, pyrite increases and many trace elements are enriched. The Fe/Al paleoredox proxy and the enrichment of trace-metals like uranium reveal prevailing anoxic conditions in the sediment and groundwater. This is more indicative for a depositional than a mobilization feature. The influence of the groundwater can therefore be classified as limited due to its reducing conditions at this transition.

The aim is to establish a method for analytically distinguishing between features of deposition, diagenesis, alteration and mobilization. This will allow assessment of the long-term integrity of the Opalinus Clay as a host rock and the surrounding formations. The gained understanding of the hydrogeological influence on the geochemical conditions within a system is to be transferred to other potential repository sites.

How to cite: Schleicher, A., Bonitz, M., Hennig, T., Stammeier, J., Jaeggi, D., and Kühn, M.: Geochemical profiles in the hydrogeological system of the Opalinus Clay, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1317, https://doi.org/10.5194/egusphere-egu24-1317, 2024.

EGU24-1916 | ECS | Orals | ERE3.2 | Highlight

Radionuclide sorption in the far field: Geostatistical simulation of crystalline rock to assess uncertainties due to heterogeneities 

Alexandra Duckstein, Solveig Pospiech, Raimon Tolosana-Delgado, and Vinzenz Brendler

In the event of radionuclides leaking from a deep geological repository for radioactive waste, they can reach the ecosphere through fluid migration pathways in the rock and aquifers. Retention mechanisms such as the sorption of radionuclides on the minerals along such pathways influence the migration patterns and are thus an essential part of the safety requirements. Consequently, determining the mineral composition and its spatial distribution of a crystalline host rock is an important task in the safety assessment for potential repositories.

In the SANGUR project (Systematic sensitivity analysis for mechanistic geochemical models using field data from crystalline rock) we aim to determine which parameters and their uncertainties are essential for developing models for the simulation of radionuclide retention in crystalline rock. Radionuclide retention is substantially affected by sorption processes on the mineral surfaces, described by distribution coefficients (Kd values). A subsequent sensitivity analysis will help to identify the most influential parameters.

In addition to the groundwater composition and the thermodynamic sorption data, the mineralogy and its heterogeneity of the host rock play an important role in establishing the model. For the sensitivity analysis, in turn, it is vital to be able to describe the uncertainties of the individual parameters in the model.

To quantify the uncertainties, we simulate crystalline rock based on MLA (Mineral Liberation Analyzer image) data using Multinary Random Fields geostatistics. The focus is not only on the mineral composition of the bulk rock as a function of number of mineral phases and variability in grain sizes, but above all on the determination of the mineral composition of the exposed surfaces with which the aqueous phase comes into contact and on which sorption processes will  thus preferentially take place.

Besides the question of how detailed the rock must be modeled in order to adequately capture the heterogeneities, the question of the model scale or the size of the representative volume element is also addressed.

In addition to the discussion of the methodology and the results of the host rock simulations, we show the results of an initial study that enables us to determine what size the representative volume element should have in order to best describe the heterogeneities of the host rock for the subsequent calculation of the Kd values and their uncertainties.

How to cite: Duckstein, A., Pospiech, S., Tolosana-Delgado, R., and Brendler, V.: Radionuclide sorption in the far field: Geostatistical simulation of crystalline rock to assess uncertainties due to heterogeneities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1916, https://doi.org/10.5194/egusphere-egu24-1916, 2024.

The safety of repositories for high-level radioactive waste has to be assessed for very long time periods (e.g., 1 Ma by German regulations), which implies that the impact of potential future cold stages and glaciations on the geological barrier of a repository needs to be considered. The largest impact may occur if a repository site is transgressed by an ice sheet or at least in the immediate proximity of an ice margin. However, also repository sites outside the maximum ice-sheet extent may be affected. Examples of relevant processes with potentially huge impacts include glacigenic erosion and ice-load induced deformation of rocks. Erosion by glaciers and meltwater is capable of mobilising and redistributing substantial amounts of rock and sediment. Overdeepened basins and (tunnel) valleys may attain depths of more than 500 m, which is within the depth range considered for repositories. Subglacial overdeepenings form independently of any regional base level as their formation relates to pressurised meltwater that effectively removes sediment.

Ice-load induced deformation of rocks includes glacial isostatic adjustment (GIA), deformation of salt structures and glacitectonics. The weight of an ice sheet triggers long-wavelength glacial isostatic adjustments, which strongly modify the regional stress field. Such changes of the stress field may cause the activation or shutdown of faults and affects areas beyond the ice margin. More locally, ice-sheet loading may trigger the deformation of salt structures due to the viscous behaviour of salt rocks. Glacitectonic deformation affects near surface rocks and includes the formation of glacitectonic shear zones, folds and faults. Movements of rock masses induced by ice loading, particularly along faults, have the potential of creating fluid pathways. Additionally, glacitectonic thrusting can relocate coherent rock masses from depths of up to 350 m.

Key to assessing the potential impact of future glaciations is the thorough understanding of the processes during past glaciations, which serve as analogues for the future. The effects of past glaciations can be analysed to reconstruct processes and allow the quantification of past extreme scenarios (e.g., depth of erosion). Numerical models are another important tool and allow the quantification and evaluation of controlling factors and the testing of extreme values (e.g., thickness of ice sheets). Ideally, both approaches should be combined to assess the potential impact of a glaciation on the geological barrier of a repository.

Examples will be presented from current projects incorporating reconstructions of Pleistocene processes into long-term safety assessments. The first case study is on the maximum depth of Pleistocene erosion in northern Germany (Breuer et al. 2023). Based on the mapped depth zones, the potential for erosion can be assessed. The second case study is a numerical simulation of the response of salt structures to ice-sheet loading (Lang & Hampel 2023), which provides new insights into the relevant controlling factors of ice-salt interactions.

 

References

Breuer et al. (2023) E&G Quat. Sci. J., 72, 113-125, DOI: https://doi.org/10.5194/egqsj-72-113-2023

Lang & Hampel (2023) Intern. J. Earth Sci. 112, 1133-1155, DOI: https://doi.org/10.1007/s00531-023-02295-5

How to cite: Lang, J., Bebiolka, A., Breuer, S., Hampel, A., and Noack, V.: Assessing the impact of potential future glaciations on the long-term safety of radioactive waste repositories: relevant processes and examples from current studies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3146, https://doi.org/10.5194/egusphere-egu24-3146, 2024.

EGU24-3471 | Posters on site | ERE3.2

Understanding Geological Key Factors for Radionuclide Retention: Insights from Sensitivity Analysis on Varied Crystalline Host Rock Compositions 

Solveig Pospiech, Frank Bok, Mostafa Abdelhafiz, Alexandra Duckstein, Elmar Plischke, and Vinzenz Brendler

The secure disposal of nuclear waste is of high societal concern, necessitating the development of deep geological repositories as a reliable solution. A key aspect of repository safety lies in understanding the far field, particularly the host rock, to predict the long-term behavior and migration of radionuclides within the geological environment from the deposit up to the ecosphere. This study addresses the specific challenges associated with crystalline host rocks.

Crystalline host rocks could be on the one hand of granitic composition and texture, but the term is also used for host rocks of metamorphic origin. While inside a large granitic intrusion there is little petrological variation expected, metamorphic rocks or the intrusion rim can exhibit complex structures in terms of structural geology as well as mineral composition, especially along potential fluid migration pathways. Consequently, this leads to a multitude of possible rock-composition/fluid-composition interactions and thus significantly affects the retention potential of radionuclides as opposed to the simplified model of an isotropic, uniform granite. The results of the study will allow to determine which components of the host rock are important to be included in geostatistical models which in turn serve as basis to estimate uncertainties of reactive transport through crystalline rocks.

Our study involves the development of Python code to feed chemical modelling software like PHREEQC or Geochemist’s Workbench© with varying mineral compositions and chemical conditions of the aqueous phase, following a specific Quasi-Monte-Carlo sampling scheme. The application of compositional data analysis principles is essential to guarantee a meaningful sampling of constraint concentration data, such as mineralogical rock compositions or element concentrations in aqueous phases. Given that compositional data sum to a fixed total, each mineral content becomes a dependent variable in relation to the other contents. Recognizing and accounting for these interdependencies is crucial to ensuring the integrity of the sampling. The chemical modelling software relies on Surface Complexation Models (SCM) for each mineral phase to calculate the distribution coefficient (Kd-value) for the radionuclide (here: uranium) in the respective setting. Furthermore, a global sensitivity analysis is employed to investigate the complex interactions between mineralogical variations and radionuclide behavior. In this study, two techniques are employed namely, High-Dimensional Model Representation (HDMR) and Cumulative Sum of Univariate Nonlinear Regression (CUSUNORO) plots. The application of HDMR allows for a detailed investigation of high-dimensional parameter spaces, while CUSUNORO plots provide a visual representation of cumulative sensitivity effects.

This study presents a complete workflow of modelling how petrological variations in crystalline host rocks, including both granitic and metamorphic compositions, affects radionuclide retention. This approach advances the understanding of nuclear waste disposal and provides valuable tools for assessing the retention potential of radionuclides in diverse geological settings.

How to cite: Pospiech, S., Bok, F., Abdelhafiz, M., Duckstein, A., Plischke, E., and Brendler, V.: Understanding Geological Key Factors for Radionuclide Retention: Insights from Sensitivity Analysis on Varied Crystalline Host Rock Compositions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3471, https://doi.org/10.5194/egusphere-egu24-3471, 2024.

EGU24-3648 | ECS | Posters on site | ERE3.2

Temperature and reaction time dependence of (Na,Ca,Cs)-zeolite formation. 

Amber Zandanel, Alyssa McKanna, Marlena Rock, Kirsten Sauer, and Florie Caporuscio

Long-term stability of engineered barrier system (EBS) materials in repository conditions is a primary concern for radioactive waste repository success. EBS designs generally include bentonite as barrier between the canister and host rock to provide: 1) a physical barrier to prevent natural fluid from interacting with the waste package and 2) a chemical barrier that attenuates radionuclide migration. Bentonite interaction with host rock and groundwater in water-saturated geologic repositories may result in the formation of secondary minerals that affect the sealing properties of the bentonite. Specifically, the formation of zeolites may negatively affect bentonite swelling properties but may also help attenuate radionuclide migration through sorption and incorporation into zeolite structures. Here we discuss the experimental formation of analcime-group zeolite minerals with Na-, Ca-, and Cs-endmembers (analcime, wairakite, and pollucite, respectively) through hydrothermal bentonite alteration in geologic repository conditions.

Experimental work was conducted at elevated pressure and temperatures conditions relevant to underground repositories. High-pressure Cs-bentonite experiments were completed from 150-400 °C and 500-1000 bar for 14 to 62 days. Gold capsules were loaded with a 2:1 water:rock ratio of unprocessed bentonite from Colony, Wyoming and an aqueous fluid containing 2 molal CaCl + CsCl + NaCl with an initial pH of ~5.8. At 200 °C Cs was found to be entrained in different phases including the zeolite clinoptilolite. Clinoptilolite is an accessory mineral in the initial bentonite mineral assemblage and the results suggest incorporation into existing clinoptilolite rather than any Cs-clinoptilolite precipitation. At reaction temperatures ≥ 300 °C and < 450 °C we observed newly precipitated crystals of pollucite in the bentonite matrix. After reaction at 450 °C only trace amounts of Cs were identified in mineral phases: instead, we observed the formation of analcime-wairakite minerals with little or no pollucite formation. Comparing these results to analcime-wairakite-pollucite stability at a range of pressure-temperature conditions sheds light on conditions that promote Cs immobilization through incorporation in pollucite crystal structures. These results expand the range of experimentally observed zeolite formation and define pressure and temperature fields that promote Cs entrapment during hydrothermal bentonite alteration. The potential benefits of radionuclide immobilization through zeolite formation are contextualized by thermodynamic and kinetic geochemical modelling of Na-, Ca-, Cs-zeolite formation and the anticipated effects to bentonite and EBS properties over time.

How to cite: Zandanel, A., McKanna, A., Rock, M., Sauer, K., and Caporuscio, F.: Temperature and reaction time dependence of (Na,Ca,Cs)-zeolite formation., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3648, https://doi.org/10.5194/egusphere-egu24-3648, 2024.

EGU24-3920 | ECS | Posters on site | ERE3.2 | Highlight

Characterizing deep fracture zones within the natural barrier: Insights from borehole data around the KAERI underground research tunnel 

Ji-Min Choi, Soolim Jung, Doohee Jeong, Nak Kyu Kim, Kyung-Woo Park, and Young-Seog Kim

High-level radioactive waste repositories rely on multi-barrier systems, including natural and engineered barriers, crucial for long-term safety through isolation and delay functions. Improving the performance of natural barriers poses challenges, necessitating thorough evaluation via ongoing field surveys and lab tests. Natural barriers are categorized and analyzed based on lithological and structural characteristics. Structural elements such as fractures, joints, and faults play a crucial role in performance assessment as they can serve as pathways for groundwater flow. Existing studies lack a unified criterion for defining structural boundaries, prompting a systematic review to establish standards suitable for site characteristics by applying various structural factors to study area boreholes. Considering the deep location of the disposal site, borehole data plays a pivotal role. The KAERI Underground Research Tunnel (KURT) is a small-scale Underground Research Laboratory (URL) with a maximum depth of 120 m excavated within the Korea Atomic Energy Research Institute (KAERI). The boreholes used in the study were drilled to depths ranging from approximately 500 to 1,000 m within the site, including KURT. The preliminary fracture zone was identified through frequency analysis of gaps between fractures in the borehole images. As reviewed previously, the methods for defining the fracture zone can broadly emphasize the background fracture and presenting exclusion conditions or emphasize the dense area of fractures and presenting boundary conditions. For each method, the match rate with the preliminary fracture zone was validated. To confirm the correlation between the match rate and the natural state, it was compared with the actual fracture density found in the drill core. By integrating a series of processes, we could quantify standards for defining deep fracture zones using boreholes. The results of this study will contribute to a three-dimensional model of the deep brittle structure within the natural barriers. Future research can explore the identified fracture zone, surface fracture zone, and the definition of fault zones with fault rocks.

Keywords: Deep fracture zones, background fracture, brittle structure, Borehole data, KURT

Acknowledgements: This research was supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (MSIT) (2021M2E1A1085200).

How to cite: Choi, J.-M., Jung, S., Jeong, D., Kim, N. K., Park, K.-W., and Kim, Y.-S.: Characterizing deep fracture zones within the natural barrier: Insights from borehole data around the KAERI underground research tunnel, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3920, https://doi.org/10.5194/egusphere-egu24-3920, 2024.

EGU24-3991 | ECS | Posters on site | ERE3.2

Diffusion and sorption of caesium depend on the dry bulk density of bentonite 

Theresa Hennig, Sina Grossmann, and Vinzenz Brendler

Smectite-rich natural clays, usually referred to as bentonite, are used as backfill material in disposal concepts for highly-radioactive wastes. The main component of bentonite is montmorillonite, characterised by a high cation exchange capacity resulting from isomorphous substitution and swelling due to the incorporation of water molecules between the stacked clay platelets, the interlayer. These properties render bentonite an ideally suited barrier material for cationic radionuclides. Caesium is such a radionuclide that is relevant in the context of nuclear waste disposal since it is highly soluble and can be incorporated in organisms.

Migration of caesium in MX-80 bentonite (Na-montmorillonite) was investigated for different dry bulk densities (1.3, 1.6 and 1.9 g/cm³) in long-term through-diffusion experiments running for up to 600 days. Diffusion experiments of tritiated water (HTO, non-sorbing) provided the transport accessible porosities. Batch sorption experiments at varying caesium concentrations should test the transferability between dispersed and compacted systems by means of the distribution coefficient Kd (m³/kg). The synthetic pore water compositions were calculated as a function of the dry bulk density. Caesium and HTO are expected to migrate via molecular diffusion through the compacted bentonite sample. Therefore, a one-dimensional numerical model was applied to determine the transport parameters, effective diffusion coefficient De (m²/s) and rock capacity factor α (-), from the temporal evolution of the diffusive flux and the accumulated activity.

In the dispersed systems, measured Kd values increase with decreasing caesium concentration and dry bulk density. The linear sorption isotherm indicates that sorption mainly occurred via cation exchange, predominantly with ions from the interlayer. Accordingly, the higher the cation concentration in the contacting pore water, less caesium is exchanged due to competing effects. At low concentrations (<10-6 mol/L), however, the measured sorbed caesium concentrations do not match exactly with the isotherm. This can be attributed to impurities in form of illite-smectite mixed layers. With increasing caesium concentration, measured Kd decreases due to saturation of the high affinity sites at the illite surfaces. Kd values differ by a factor of up to ten between batch and compacted systems. With compaction, the amount of water in the interlayer decreases. This, in turn, affects the space and ability to hydrate sodium so that it is exchanged with the less hydrated caesium from the bulk solution. Accordingly, Kd values are not transferable due to thermodynamic changes of the exchange process with compaction. Consequently, caesium sorption depends on the ionic strength, the compaction and on the caesium concentration.

With increasing bulk density, the apparent diffusion coefficients of caesium decrease by a factor of ten. In general, diffusion of caesium was twice as high as that of HTO. This can be attributed to an additional transport pathway in the interlayer, which is not accessible for neutral species. For the transient phase, there was an offset between simulations and experiments, what might be explained by higher temperatures at the beginning of the experiments. Simulated and experimental steady-state phases are in line. With compaction, sorption increases, and thus diffusivity decreases.

How to cite: Hennig, T., Grossmann, S., and Brendler, V.: Diffusion and sorption of caesium depend on the dry bulk density of bentonite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3991, https://doi.org/10.5194/egusphere-egu24-3991, 2024.

EGU24-7277 | Posters on site | ERE3.2 | Highlight

Geophysical Understanding of Coupled Thermal-Hydro-Mechanical Dynamics in Rock Salt During Heating 

Yuxin Wu, Jiannan Wang, Hang Chen, Linqing Luo, Shawn Otto, Kristopher Kuhlman, Liange Zheng, and Jens Birkholzer

The distinctive properties of salt, such as low permeability, high thermal conductivity, and self-sealing features, make it a suitable medium for storing heat-generating radioactive waste. Understanding the thermal, hydrological, and mechanical (THM) processes, including permeability evolution and brine migration around the heat source, is crucial for safety. The Brine Availability Tests in Salt (BATS) at the Waste Isolation Pilot Plant were conducted to investigate these processes, employing an array of sensors and techniques like electrical resistivity tomography (ERT), fiber optic distributed temperature sensing (DTS), and strain sensing (DSS). These techniques monitored temperature changes, brine movement, and stress conditions in the salt.

This presentation highlights the results from ERT, DTS, and DSS in controlled heating experiments, focusing on the response differences across various heating events. The analysis, augmented by Discrete Element Models (DEM) simulations, showed that resistivity changes were sensitive to temperature and brine movement. A significant decrease in resistivity, especially beyond temperature effects, indicated brine migration or permeability changes. The DTS and DSS data captured the evolving thermal and mechanical responses of the salt to heating and cooling cycles, including salt deformation, and creeping towards the drift wall.

Joint analysis of ERT, DTS, and DSS data provided an integrated understanding of THM processes in salt during heating. Consistent heating and brine migration patterns were observed across different events. Ongoing work aims to combine all monitoring data for a deeper insight into the coupled behaviors in salt formations, offering valuable calibration and benchmarking for numerical models.

How to cite: Wu, Y., Wang, J., Chen, H., Luo, L., Otto, S., Kuhlman, K., Zheng, L., and Birkholzer, J.: Geophysical Understanding of Coupled Thermal-Hydro-Mechanical Dynamics in Rock Salt During Heating, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7277, https://doi.org/10.5194/egusphere-egu24-7277, 2024.

EGU24-7840 | ECS | Posters on site | ERE3.2

Groundwater life expectancy simulations in strongly coupled density-dependent flow above a salt dome 

Jonas Suilmann, John Molson, and Thomas Graf

In the overburden of salt domes, salt is dissolved by groundwater, resulting in groundwater flow under highly variable water densities. Density-dependent flow is therefore important in assessing potential migration pathways for radionuclides accidentally released from high-level nuclear waste repositories located in salt domes. Groundwater life expectancy has been established as a safety indicator for radionuclide travel times and is therefore of particular interest.

The objective of this study is to numerically investigate and understand the effects of uncertain transport parameters on density-dependent flow above a salt dome. The effects of density-dependent flow and salt transport, along with the transport parameters on the groundwater life expectancy are investigated numerically using the FEM code Saltflow. Groundwater life expectancy can be directly simulated using an advection-dispersion equation. The life expectancy depends on the transport parameters in two ways, first via the flow velocities calculated in the density-dependent flow simulation which depend on the dispersion terms, and second directly for the calculation of the life expectancy. This suggests a strong and also highly non-linear dependence of life expectancy on the transport parameters.

Preliminary results support this interpretation. Longitudinal macrodispersivity shows a considerable influence on groundwater life expectancy. Strongly non-linear results are also obtained depending on the transverse vertical dispersivity. Increasing the transverse dispersivity up to a certain threshold leads to an increase of the maximum life expectancy in the model domain. Above this threshold, which depends on the longitudinal dispersivity, the maximum life expectancy decreases. Life expectancy also strongly increases with a decreasing diffusion coefficient. These results highlight the importance of considering uncertainty in the transport parameters when numerically evaluating groundwater life expectancy in density-dependent flow in the context of nuclear waste disposal.

How to cite: Suilmann, J., Molson, J., and Graf, T.: Groundwater life expectancy simulations in strongly coupled density-dependent flow above a salt dome, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7840, https://doi.org/10.5194/egusphere-egu24-7840, 2024.

EGU24-8225 | Posters on site | ERE3.2 | Highlight

Towards a comprehensive model to estimate redox capacity of clay rocks studied as natural barriers for radioactive waste disposal 

Miroslav Honty, Alwina Hoving, Lander Frederickx, Jean-Marc Greneche, and Daniel Traber

The Boom Clay (BC) in Belgium and the Opalinus Clay (OPA) in Switzerland are studied as potential host rocks for radioactive waste disposal in the frame of national programmes. In the assessment of the long-term natural barrier evolution, redox capacity is an important physical-chemical parameter to consider as it may affect the speciation and migration behavior of the released radionuclides from the waste. In this respect, iron plays an important role in the electron transfer and thus may influence the speciation and transport of many redox sensitive radionuclides. The clay minerals, commonly present in these rocks, contain iron in the octahedral and tetrahedral sheets of their structure (e.g. illite, smectite, mixed layer illite-smectite (I-S) and chlorite). Despite their relatively high abundance in the sedimentary rocks, the electrochemical activity of iron within clay minerals may vary from as high as 100% in the case of pure smectite, through 41% in the mixed 70/30 layer I-S, 10% in illite and only 2% in chlorite. The electrochemical activities of non-clay iron-bearing minerals, is low in the case of pyrite (from 2 to 12%) and zero in the case of siderite.

In order to estimate the redox capacities of BC and OPA, Fe distribution, redox state and electrochemical activity were determined by a combination of quantitative XRD analysis (QXRD), XRF, phenanthroline, 57Fe Mössbauer spectroscopy and mediated electrochemical oxidation (MEO) and mediated electrochemical reduction (MER) measurements. In the bulk OPA clay samples, the Fe2+ states dominate over Fe3+ states, whereas Fe3+ states dominate over Fe2+ states in the studied bulk BC samples. In both cases, illite, I-S and smectite are the main Fe3+ carriers, while chlorite, pyrite and siderite are the main Fe2+ carriers. Fe distribution and the valence state are therefore controlled by the quantitative mineralogical composition in both rocks. The results of the MER and MEO measurements indicate that total electron transfer capacity (ETC) varies in the range between 45 and 64 µmol e-/g bulk OPA and between 160 and 181 µmol e-/g bulk BC. In most of the studied samples, the electron accepting capacity (EAC) is higher than the electron donating capacity (EDC). The measured EACs positively correlate with increasing Fe3+ contents, smectite content and cation exchange capacities. The correlation between measured EDCs and Fe2+ contents is less satisfactory, most likely due to overall low Fe2+ electrochemical activities reported for pure pyrite, chlorite and siderite. The quantitative mineralogical composition and available electrochemical data of the pure minerals were used to calculate the theoretical ETCs, EDCs and EACs of the studied OPA and BC samples. Despite relatively large uncertainties in the electrochemical activities in the EDC field, the correlation between theoretical and experimental EACs and ETCs is relatively good in both studied cases (R2 = 0.83 and 0.76, respectively for EAC and ETC in the case of OPA and R2=0.74 and 0.84 in the case of BC). The proposed mineral electrochemical model should be tested on larger data sets to verify its general applicability to other clay formations.

How to cite: Honty, M., Hoving, A., Frederickx, L., Greneche, J.-M., and Traber, D.: Towards a comprehensive model to estimate redox capacity of clay rocks studied as natural barriers for radioactive waste disposal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8225, https://doi.org/10.5194/egusphere-egu24-8225, 2024.

EGU24-10758 | ECS | Orals | ERE3.2

Chemo-Hydro-Mechanical variational phase-field fracture model  

Mostafa Mollaali, Renchao Lu, Keita Yoshioka, Wenqing Wang, Vanessa Montoya, and Olaf Kolditz

We present a fully coupled chemo-hydro-mechanical variational phase field model for simulating fracture initiation and propagation, including chemical reactions in cementitious systems. Using a staggered approach, we coupled three subprocesses: (i) fluid flow in porous media, (ii) reactive transport, and (iii) mechanical deformation of fractured porous media using a variational phase field. The geochemical package PHREEQC was coupled in an operator-splitting approach with a finite element transport solver to calculate chemical reactions in thermodynamic equilibrium (dissolution or precipitation), considering changes in porosity. Mechanical deformation and fluid flow were coupled using the fixed-stress splitting approach. For chemical damage, we introduced a variable to a constitutive relation representing a degree of chemical damage ranging from zero (intact) to one (damaged material). This chemical damage variable represents changes in porosity caused by chemical reactions independently from the phase field variable that represents the mechanical damage.

Additionally, as effective diffusion and hydraulic conductivity increase in the presence of fracture and changes in porosity, the phase field variable and chemical damage should impact the hydraulic conductivity and the diffusion coefficient. We conducted different benchmarks to demonstrate the model's capabilities and properties in capturing fracture initiation and propagation due to chemical reactions. The proposed model was implemented in the open-source finite element framework OpenGeoSys. 

How to cite: Mollaali, M., Lu, R., Yoshioka, K., Wang, W., Montoya, V., and Kolditz, O.: Chemo-Hydro-Mechanical variational phase-field fracture model , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10758, https://doi.org/10.5194/egusphere-egu24-10758, 2024.

EGU24-11390 | ECS | Orals | ERE3.2 | Highlight

Kinetic Monte Carlo as a bridge between nano- and macroscales: a case study on dissolution of (Ba,Sr,Ra)SO4 solid solution 

Nikolai Trofimov, Inna Kurganskaya, and Andreas Luttge

Barite (BaSO4) is a common rock-forming mineral, controlling barium behavior in Earth’s crust and marine water. This mineral can incorporate Sr and Ra into the crystal lattice by forming binary and ternary solid solutions. It makes barite a promising material for use in nuclear storages e.g., for nuclear waste containers. The achievement of high levels of safety in modern nuclear waste deposits requires studies on container’s material-water interaction. The data on solid-liquid interface reactions can be obtained by both experimental and computational methods. The most widespread experimental methods for studying surface reaction kinetics are Atomic Force Microscopy (Putnis, 1995; Bosbach, 1998; Risthaus, 2001; Kuwahara, 2011) and Vertical Scanning Interferometry (Luttge, 2010). However, these methods do not provide information on reaction mechanisms at the molecular scale. Approaches such as Density Functional Theory and Molecular Dynamics give detailed information of the reaction mechanisms at the nano-scale but are limited by the computational costs, system size, and reactions time period (Kurganskaya et al., 2022). Kinetic Monte Carlo is a stochastic approach, which can be successfully used as a connecting link between molecular and macroscopic scales, incorporating both experimental (AFM, VSI) and computational (DFT, MD) data. The KMC model of pure barite dissolution in water was developed by Kurganskaya et al., 2022. We present a new Kinetic Monte Carlo model of mineral-water dissolution in (Ba,Sr,Ra)SO4 system and discuss the general approaches for KMC models parameterization, based on a crystal chemistry of studied material.

Putnis, A., Junta-Rosso, J. L., & Hochella Jr, M. F. (1995). Dissolution of barite by a chelating ligand: An atomic force microscopy study. Geochimica et Cosmochimica Acta59(22), 4623-4632.

Bosbach, D., Hall, C., & Putnis, A. (1998). Mineral precipitation and dissolution in aqueous solution: in-situ microscopic observations on barite (001) with atomic force microscopy. Chemical Geology151(1-4), 143-160.

Risthaus, P., Bosbach, D., Becker, U., & Putnis, A. (2001). Barite scale formation and dissolution at high ionic strength studied with atomic force microscopy. Colloids and Surfaces A: Physicochemical and Engineering Aspects191(3), 201-214.

Kuwahara, Y. (2011). In situ Atomic Force Microscopy study of dissolution of the barite (0 0 1) surface in water at 30° C. Geochimica et Cosmochimica Acta75(1), 41-51.

Luttge, A., & Arvidson, R. S. (2010). Reactions at surfaces: a new approach integrating interferometry and kinetic simulations. Journal of the American Ceramic Society93(11), 3519-3530.

Kurganskaya, I., Rohlfs, R. D., & Luttge, A. (2023). Multi-scale modeling of crystal-fluid interactions: state-of-the-art, challenges and prospects.

Kurganskaya, I., Trofimov, N., & Luttge, A. (2022). A Kinetic Monte Carlo Approach to Model Barite Dissolution: The Role of Reactive Site Geometry. Minerals12(5), 639.

How to cite: Trofimov, N., Kurganskaya, I., and Luttge, A.: Kinetic Monte Carlo as a bridge between nano- and macroscales: a case study on dissolution of (Ba,Sr,Ra)SO4 solid solution, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11390, https://doi.org/10.5194/egusphere-egu24-11390, 2024.

The computational burden associated with coupled reactive transport simulations limits their application coarse models and thus to oversimplified geological and geochemical features, with obvious repercussions on uncertainty and safety assessment of nuclear waste disposal facilities. Techniques from approximated computing can however be leveraged to accelerate simulations of large-scale, heterogeneous domains. These include both surrogate models based on machine learning and artificial intelligence (ML/AI) to replace more costly numerical geochemical simulators, and algorithmic improvements such as interpolation from previously computed geochemical simulations stored and indexed in efficient data structures such as  Distributed Hash Tables during coupled simulations. In this contribution we demonstrate recent advancements in physics-based geochemical surrogates achieved within the ML-Benchmark initiative from the DONUT/EURAD project for Uranium diffusion in clay subject to exchange and sorption. Furthermore, the algorithm implemented in the reactive transport simulator POET [1] based on automatic clustering of multivariate data and subsequent interpolation enables the simulation of large-scale, heterogeneous reactive transport scenarios on uniform grids of magnitude of million grid elements at reduced computational costs.


[1] Marco De Lucia, Michael Kühn, Alexander Lindemann, Max Lübke, and Bettina Schnor, 2021: POET (v0.1): speedup of many-core parallel
reactive transport simulations with fast DHT lookups, Geoscientific Model Development, 14, 7391--7409. https://doi.org/10.5194/gmd-14-7391-2021

How to cite: De Lucia, M., Lübke, M., and Schnor, B.: 2D simulations of Uranium diffusion in clay: geochemical surrogate models and accelerated coupled reactive transport simulations with POET, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11632, https://doi.org/10.5194/egusphere-egu24-11632, 2024.

There is a need for improved understanding of flow channelling and solute transport in fractured crystalline rock in the context of safety analysis of geological repositories for spent nuclear fuel. Numerical discrete fracture network (DFN) models of sparsely fracture rock often employ an assumption of effectively homogeneous properties at the scale of individual fractures. However, real-world fractures have rough surfaces which translates to internal variability in aperture and permeability which can impact transport properties. Although it is known that internal variability controls flow channelling at the scale of single fractures, there is a lack of understanding of effects at the bedrock scale of multiple connected fractures forming networks. Therefore, it is relevant to study internal fracture variability in DFN models to better understand potential impacts on flow and transport.

In this contribution, flow channelling and solute transport in three-dimensional fracture networks with internal variability in permeability is investigated using a numerical DFN flow model with a stochastic Lagrangian transport framework. The fracture network properties are obtained from field measurements and data of fractured rock from the Forsmark site in Sweden, which is a planned location for the construction of the spent nuclear fuel repository. Different assumptions for describing the correlation length of the textures used for internal variability of fracture permeability are considered. Multiple realisations are generated and it is shown that cases with strong correlation length can lead to reduced travel times and reduced solute retention when compared to cases assuming homogenous fractures. The changes observed occur only for a small fraction of early arrivals, whereas bulk mass is essentially unaltered, and late mass breakthrough with strong retention is generally enhanced. Cases with weak correlation lengths generally have minor impacts. Thereby key thresholds for cases where flow channelling is controlled by internal fracture variability versus network scale connectivity are discussed, and a need to understand and evaluate correlation structures for real-world fractures is highlighted.

How to cite: Frampton, A.: Effects of internal fracture variability on flow channelling in discrete fracture network models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11766, https://doi.org/10.5194/egusphere-egu24-11766, 2024.

EGU24-12859 | ECS | Posters on site | ERE3.2

The site selection data hub: a data-centric approach for integrated simulation workflow management in radioactive waste disposal site selection 

Qian Chen, Marc S. Boxberg, Nino Menzel, Maria F. Morales Oreamuno, Wolfgang Nowak, Sergey Oladyshkin, Florian M. Wagner, and Julia Kowalski

Given the importance of ensuring the safe disposal of radioactive waste, it is vital to understand the targeted subsurface systems and to build physics-based models to predict their dynamic responses to human interventions. Constructing robust predictive models, however, is very challenging due to the systems’ complexity as well as the scarcity and cost of geophysical data acquisition. Optimal matching of data acquisition and predictive simulations is therefore necessary and can be achieved via integrating predictive process modeling, Bayesian parameter estimation, and optimal experimental design into a modular workflow. This allows to quantify the information content of measurement data and therefore enables optimal planning of data acquisition and monitoring strategies. Conducting such data-integrated simulation studies, however, requires a robust workflow management that ensures reproducibility, error management, and transparency. 

To meet this demand, we established a data-centric approach to workflow control combining error-managed simulations with a functional data hub, providing simulations with direct access to a database of essential material properties. The latter are being made available as site specific scenario compilations along with uncertainty margins and meta information.  

The data hub serves as an interface facilitating seamless data and simulation exchange to support subsequent model-driven decision-making processes and guarantees that simulations are conducted using manageable, comparable, and reproducible test cases. Furthermore, it ensures that the simulation results can be readily transferred to a designated repository allowing for real-time updates of the model. The implementation of the data hub is based on a Python-based framework for two different use cases:

1)  GUI-based use case: The graphical user interface (GUI) facilitates data import, export, and visualization, featuring distinct sections for geographic data representation, structured table organization, and comprehensive visualization of physical properties in varying dimensions.

2) Module-based use case: Built on the YAML-based data-hub framework, it enables direct integration of simulation modules storing measurements and model parameters in the YAML data format.

The data is systematically organized to furnish a versatile data selection framework that allows information to be extracted from a variety of references, including specific on-site measurements, laboratory measurements and other references, thereby enabling a comprehensive exploration of different reference-oriented scenarios.

This study showcases the data hub as a management infrastructure for executing a modular workflow. Multiple models—such as process and impact models as well as their surrogates and geophysical inverse models—are generated within this workflow utilizing scenarios provided by the data hub. Our study shows that adopting a data-centric approach to control the simulation workflow proves the feasibility of conducting different data-integrated simulations and enhances the interchangeability of information across different stages within the workflow. The paradigm of sustainable model development ensures reproducibility and transparency of our results, while also offering the possibility of synergetic exchange with other research areas. 

How to cite: Chen, Q., Boxberg, M. S., Menzel, N., Morales Oreamuno, M. F., Nowak, W., Oladyshkin, S., Wagner, F. M., and Kowalski, J.: The site selection data hub: a data-centric approach for integrated simulation workflow management in radioactive waste disposal site selection, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12859, https://doi.org/10.5194/egusphere-egu24-12859, 2024.

EGU24-13289 | Orals | ERE3.2 | Highlight

Assessing the effects of long-term landscape evolution on the overburden of deep repository sites: application to northern Switzerland 

Angela Landgraf, Michael Schnellmann, Kristin Vogel, Wolfgang Betz, Daniel Straub, Wolfgang Schwanghart, J Ramon Arrowsmith, Simon Mudd, Emma Graf, Andreas Ludwig, Florian Kober, Gaudenz Deplazes, Urs Fischer, Jens Becker, Fabian Maier, and Frank Scherbaum

The safety assessment of radioactive waste repositories requires scenarios and forecasts of the erosional, climatic, and tectonic future evolution. One of the major challenges in the assessment of long-term landscape evolution for safety is that the relevant processes, models and model parameters are subject to a range of significant uncertainties. Assessments should provide the full range of conceivable developments using the best available scientific knowledge. Here, we present an assessment framework for future erosion with a rigorous uncertainty management. The approach anticipates erosion from fluvial, hillslope, and glacial processes over a timescale of 105-106 years. Uncertainties are addressed in a hybrid way, using probabilistic methods in combination with a scenario approach, whereby the chosen scenarios cover a wide range of possibilities. A protocol was followed to derive model parameter uncertainties that respect individual estimates of experts. The entire process is accompanied by a sensitivity analysis. We used the workflow to assess erosion in Northern Switzerland over the next million years. The results serve as input to site a deep geological repository for nuclear waste in Switzerland and to demonstrate its long-term safety.

How to cite: Landgraf, A., Schnellmann, M., Vogel, K., Betz, W., Straub, D., Schwanghart, W., Arrowsmith, J. R., Mudd, S., Graf, E., Ludwig, A., Kober, F., Deplazes, G., Fischer, U., Becker, J., Maier, F., and Scherbaum, F.: Assessing the effects of long-term landscape evolution on the overburden of deep repository sites: application to northern Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13289, https://doi.org/10.5194/egusphere-egu24-13289, 2024.

EGU24-13566 | ECS | Posters on site | ERE3.2

Physical and chemical effects of natural zeolites additives on the cementitious stabilization of cesium and barium isotopes in boric acid liquid waste   

Gabriel Iklaga, Nándor Kaposy, Istvan Tolnai, Viktória Gável, Margit Fábián, Csaba Szabó, Péter Völgyesi, and Zsuzsanna Szabó-Krausz

Boric acid is used in pressurized water reactor (PWR) systems as an efficient neutron absorber for activity control which aids in the maintenance of steady state operating temperature control. The boric acid liquid waste produced from the system might contain low concentrations of nuclear fission produced radioisotopes such as 137Cs and its metastable decay product 137mBa (also named as 137mCs). Adequate repository storage of this high-volume liquid waste has become environmentally important for study as these radioisotopes can become bio-available in the natural systems if not effectively immobilized. Our research main aims are to assess the geochemical effects of natural zeolite (i.e., clinoptilolite and mordenite) additives in sulfoaluminate cement (SAC) and ordinary Portland cement (OPC) blends for optimizing chemical and mechanical stability for immobilizing boric acid liquid waste and contained fission isotopes, mentioned above in solidified cement paste waste forms.

To accomplish our research goal, the natural zeolite additives at ratios ranging from 0%, 5%, 10%, 15% and 20%, respectively, were added to a benchmarked OPC to SAC blend (i.e., 80% OPC to 20% SAC) based on results from our previous experiments. The samples were then mixed with simulated boric acid liquid waste containing Cs and Ba isotopes and allowed to cure for 28 days. Standardized reference leaching test was carried out on the cured solid waste forms for 11 days and then they were analyzed by standardized compressive strength test, scanning electron microscopy (SEM) for morphology and X-ray diffraction (XRD) for mineralogy. While the liquid waste solutions (leachate) from the leaching test were analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and inductively coupled plasma mass spectroscopy (ICP-MS) to assess elemental and isotopic changes.  

How to cite: Iklaga, G., Kaposy, N., Tolnai, I., Gável, V., Fábián, M., Szabó, C., Völgyesi, P., and Szabó-Krausz, Z.: Physical and chemical effects of natural zeolites additives on the cementitious stabilization of cesium and barium isotopes in boric acid liquid waste  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13566, https://doi.org/10.5194/egusphere-egu24-13566, 2024.

EGU24-13990 | ECS | Orals | ERE3.2

The roles of clay minerals and/or organic ligands in the mobility of uranium: an insight for geological disposal of radioactive waste 

Qingyin Xia, Yuqing Niu, Longcheng Liu, Zhean Zhang, and Tingting Xie

Clay and clay rocks are being considered as possible barriers for nuclear waste disposal worldwide, due to their high adsorption capacity and limited hydraulic conductivity. Moreover, clay minerals have been regarded as one of the major Fe-containing phases in the Earth’s crust due to their ubiquitous occurrences in soil and sediments.  Hence, a solid understanding of uranium interactions with Fe(III)-bearing clay minerals is needed for the optimal design and long-term stewardship of uranium waste disposal. Besides clay minerals, metal-chelating ligands were found at appreciable concentrations in certain uranium-contaminated sites due to their prevalent use as decontaminant (e.g., complexing) agents in radioactive waste streams, which ultimately impacted the redox kinetics of U in proximity.

Herein, we report a combined effect of Fe(III)-rich nontronite (NAu-2) and environmentally prevalent organic ligands on re-oxidation of biogenic UO2 at circumneutral pH. After 30 d incubation, structural Fe(III) in NAu-2 oxidized 45.50% UO2 with an initial rate of 2.68*10-3 mol*m-2*d-1. The addition of citrate and EDTA greatly promoted the oxidative dissolution of UO2 by structural Fe(III) in NAu-2, primarily through the formation of aqueous ligand-U(IV) complexes. In contrast, a model siderophore, DFOB, partially inhibited UO2 oxidation due to the formation of a stable DFOB-Fe3+ complex. The resulting U(VI) species intercalated into the NAu-2 interlayer, driving UO2 dissolution by keeping dissolved U(VI) concentrations low. Our results highlight the importance of organic ligands on the oxidative dissolution of U(IV) minerals by Fe(III)-bearing clay minerals and have important implications for the design of nuclear waste storage and remediation strategies, especially in clay- and organic-rich environments.

How to cite: Xia, Q., Niu, Y., Liu, L., Zhang, Z., and Xie, T.: The roles of clay minerals and/or organic ligands in the mobility of uranium: an insight for geological disposal of radioactive waste, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13990, https://doi.org/10.5194/egusphere-egu24-13990, 2024.

Geothermal resources have been emerged as a practical and cost-effective clean energy alternative to fossil fuels in many countries. The study of geothermal water can provide valuable insights for sustainable long-term utilization of geothermal energy and for understanding deep geologic environments for diverse emerging geo-energy technologies. For this study, chemical and isotopic tracers (δ2H, δ18O, δ13C, 14C) of thermal groundwaters over South Korean peninsula were investigated to evaluate their geochemical characteristics and reservoir parameters (i.e., temperature, recharge and circulation depth of groundwater, and circulation dynamics). Based on geochemical characteristics, geologic setting, and geographical location, South Korean thermal groundwaters were categorized into five groups (Kim et al., 2020): saline, CO2-rich, high-pH alkaline, sulfate-rich, and diluted freshwater. These distinct hydrochemical characteristics are determined by complex geochemical processes which include calcite dissolution, plagioclase feldspar hydrolysis, CO2 gas dissolution, cation exchange, precipitation of secondary minerals (clay, calcite, fluorite), gypsum dissolution, and seawater mixing. However, each group tends to show no systematic change among outflowing temperature, hydrochemistry, and stable isotopes over time (i.e., radiocarbon age), which may indicate that thermal waters have reached an equilibrium through deep circulation over very long periods of time (millennial scales). All groups of thermal water originated from deeply circulated meteoric water, and their stable water isotope data (δ2H, δ18O) show a systematic fractionation pattern depending on the recharge altitude (Choi et al., 2023). Temperatures of geothermal reservoirs at depths were estimated by using chemical geothermometers considering the ambient geology and measured outflow temperatures. The results obtained from K-Mg, Li-Mg, Na-K-Ca, Na-K, and Si geothermometers ranged widely from a minimum of 28°C to a maximum of 207°C, with an average of 61 to 148°C. The estimated depths of groundwater circulation to form South Korean thermal waters fall between about 1.0 and 3.3 km, if calculate from the calculated average reservoir temperature and geothermal gradient data in each location. The estimated circulation depths tend to increase with decreasing stable water isotope data (δ2H, δ18O) and increasing radiocarbon (14C) ages. This study, conducted across South Korea, provides important information about the origin and evolution of deep thermal water, which may be helpful to the efficient and sustainable management of geothermal resources and to the selection of suitable sites for geologic CO2 storage or high-level radioactive waste disposal. Acknowledgements: This study was supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and the BK Plus project in Korea.

References

Choi, J., Yu, S., Park, S., Yun, S.T., Lee, J., Park, J. (2023). Hydrochemical and Isotopic Assessment of Deep Groundwater: Residence Time, Circulation and Inter-Aquifer Mixing in South Korea. Goldschmidt 2023 Abstracts. https://doi.org/10.7185/gold2023.20028

Kim, K.H., Yun, S.T., Yu, S., Choi, B.Y., Kim, M.J., Lee, K.J. (2020). Geochemical pattern recognitions of deep thermal groundwater in South Korea using self-organizing map: identified pathways of geochemical reaction and mixing. Journal of Hydrology 589, 125202. https://doi.org/10.1016/j.jhydrol.2020.125202

How to cite: Choi, J., Lee, J.-H., Park, S., Seo, H., and Yun, S.-T.: Investigating Geochemical Characteristics of South Korean Geothermal Waters and Their Reservoir Condition Using Combined Hydrogeochemical, Isotopic and Geothermometric Approaches, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15040, https://doi.org/10.5194/egusphere-egu24-15040, 2024.

The release and migration of radionuclides towards the biosphere from underground waste repositories may pose a threat to the environment and humans. Therefore, the understanding of transport processes of radionuclides in the subsurface is crucial in order to predict the arrival in the near-surface environment for effectively mitigating and managing associated risk. Processes controlling radionuclide transport may be advection, dispersion, diffusion, sorption and decay, among others.

In the context and typical locations of existing waste repositories and test sites, diffusion-dominated transport occurs. Typically, local permeabilities and flow velocities are so small that advection and dispersion would only become significant at very large timescales. The processes of diffusion, sorption (possibly modulated by pressure and temperature) and decay may often be crucial for a) predicting the gradual release and movement of contaminants from the repository into the surrounding geological formations and b) in the geological barrier itself as part of safety analyses. Therefore, understanding of barrier-specific diffusion processes is essential for assessing long-term containment and designing effective concepts to ensure reliable isolation of radionuclides over a time period long enough for their decay to safe levels and to avoid potential environmental risks associated with the disposal of radioactive waste.

In the present desktop study, we calculate diffusion-dominated transport of specific radionuclides (Tritium, Technetium, Neptunium a.o.) for various host rocks (tuff a.o.). We calculate radionuclide breakthrough curves and timescales using the 1D analytical model by Lapidus & Amundson (1952), extended for decay in Bear (1972). In order to validate transport parameters for specific radionuclides in specific rock, we analytically try to reproduce physical radionuclide diffusion experiments. Subsequently, we use the validated transport parameters to predict timescales of diffusion-dominated transport.

References:

Bear, J., 1972. Dynamics of Fluids in Porous Media. American Elsevier, New York.

Lapidus, L., & Amundson, N. R. (1952). Mathematics of adsorption in beds. VI. The effect of longitudinal diffusion in ion exchange and chromatographic columns. The Journal of Physical Chemistry, 56(8), 984-988.

How to cite: Peche, A., Tran, T. V., and Altfelder, S.: Timescales of diffusion-dominated radionuclide migration – an evaluation of selected existing nuclear waste repository sites and test sites , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15090, https://doi.org/10.5194/egusphere-egu24-15090, 2024.

EGU24-16083 | ECS | Posters on site | ERE3.2

The Influence of Burial History on the In-situ Petrophysical and Mechanical Characteristics of Pliensbachian Shale 

Raphael Burchartz, Mohammadreza Jalali, Sebastian Grohmann, Lisa Winhausen, Garri Gaus, Timo Seemann, Jochen Erbacher, Ralf Littke, and Florian Amann

Characterizing the host rocks for high-level radioactive waste disposal requires considering various rock parameters such as petrophysical (e.g., porosity, permeability and storativity) as well as mechanical (e.g., Young’s modulus) properties. The burial history and thermal maturity of rock formations, particularly shale, significantly affect these properties. Understanding the relationship between the thermal maturity and the referred properties is essential for transferring data among various test sites.

Pliensbachian shales (Lower Saxony Basin, Hils area) are characterized by a notably homogenous mineral composition. Previous studies on this formation suggest a highly variable burial history over a lateral distance of about 50 km, reaching maximum burial depths between 1300 m in the southeast to 3600 m in the northwest of this region (Gaus et al., 2022; Littke et al., 1987, 1991). In the context of the MATURITY project, eight boreholes were drilled at five different locations with varying thermal maturity along this axis. Geophysical well logging was carried out in all boreholes to investigate mineralogical (clay mineral content), petrophysical (porosity), and rock mechanical properties (e.g., dynamic Poisson's ratio). First results revealed a homogeneous clay mineralogy in all boreholes. However, significant differences were observed in both the dynamic-elastic behavior and porosity of the investigated shale formation at different locations. The obtained data can be used to establish correlations between burial history and various shale rock properties, contributing to a site-independent characterization of shale formations for long-term disposal of high-level nuclear waste.

 

 References

  • Gaus, G., Hoyer, E.M., Seemann, T., Fink, R., Amann, F., Littke, R. (2022). Laboratory investigation of permeability, pore space and unconfined compressive strength of uplifted Jurassic mudstones: The role of burial depth and thermal maturation. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 173 (3), 469-489
  • Littke, R., Baker, D. R., & Leythaeuser, D. (1988). Microscopic and sedimentologic evidence for the generation and migration of hydrocarbons in Toarcian source rocks of different maturities. Advances in Organic Geochemistry, Vol.13(Nos 1-3), 549–559.
  • Littke, R., Leythaeuser, D., Rullkötter, J., & Baker, D. R. (1991). Keys to the depositional history of the Posidonia Shale (Toarcian) in the Hils Syncline, northern Germany. Geological Society, London, Special Publications, 58(1), 311–333.

How to cite: Burchartz, R., Jalali, M., Grohmann, S., Winhausen, L., Gaus, G., Seemann, T., Erbacher, J., Littke, R., and Amann, F.: The Influence of Burial History on the In-situ Petrophysical and Mechanical Characteristics of Pliensbachian Shale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16083, https://doi.org/10.5194/egusphere-egu24-16083, 2024.

EGU24-16907 | Orals | ERE3.2

Assessing Ice-Sheet Variability for Post-Closure Safety of Deep Geological Repositories 

Johan Liakka, Jens-Ove Näslund, Rémi Vachon, and Dan J Lunt

In many regions considered for deep geological repositories (DGR) to contain nuclear waste, there will be repeated glaciations throughout periods pertinent to their long-term safety (up to 1 million years; Ma). Ice sheets can influence the containment of radionuclides through various mechanisms. For example, when the margin of an ice sheet is situated in close proximity to the DGR, groundwater flow may increase, potentially leading to enhanced erosion and corrosion of the technical barriers within the DGR. Furthermore, the temporal extent of glaciations at the DGR site impacts groundwater chemistry, such as salinity and oxygen content, as well as the magnitude of glacial isostatic adjustment and surface bedrock denudation over the ensuing 1 Ma. Consequently, evaluations of long-term DGR safety must account for uncertainties related to ice-sheet variability at the DGR site throughout the next 1 Ma, specifically addressing the frequency of glaciations (nglac) and the total duration of ice-sheet coverage (tglac). Additionally, assessments should consider the potential for ice-marginal stillstands, denoting temporary halts in the advancement and/or retreat of the ice-sheet margin over the DGR site.

The utilization of coupled ice sheet-climate models for constraining uncertainties in nglac and tglac over the next 1 Ma is not feasible due to the long timescales involved and substantial computational requirements. To assess future ice-sheet variability, we propose a simplified methodology that uses (i) reconstructions of historical ice sheets, (ii) records of past global ice-volume fluctuations, and (iii) simulations of future global ice-volume changes. These simulations are conducted using a simple multi-step climate model, which is driven by changes in insolation and radiative forcing due to atmospheric greenhouse gases.

Utilizing the proposed methodology on the Swedish site chosen for nuclear waste disposal (Forsmark) suggests that the onset of the first glaciation at the site is projected not to take place within the coming 100,000 years (100 ka), irrespective of human-induced greenhouse-gas emissions. Following the initial glacial event at Forsmark, the frequency and duration of subsequent glaciations will likely be similar to those observed in the late Quaternary (last 800 ka). Taking into consideration identified model and scenario uncertainties, the total glaciation duration (tglac) at Forsmark may either decrease by a factor of five or increase by a factor of two in comparison to the average conditions of the late Quaternary. In contrast to tglac, the number of glaciations (nglac) at Forsmark is found to be largely insensitive to the evaluated uncertainties.

The potential for ice-margin stillstands within the next 1 Ma is assessed through theoretical considerations complemented by simulations with ice-sheet model simulations. Initial findings indicate that stillstands will be brief, lasting less than 1000 years under nearly all examined scenarios. This observation aligns with historical records of stillstands during the last deglaciation. The occurrence of stillstands modestly exceeding 1000 years can only occur if a glacial maximum is promptly followed by a millennial-scale cooling event.

How to cite: Liakka, J., Näslund, J.-O., Vachon, R., and Lunt, D. J.: Assessing Ice-Sheet Variability for Post-Closure Safety of Deep Geological Repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16907, https://doi.org/10.5194/egusphere-egu24-16907, 2024.

EGU24-17411 | Posters on site | ERE3.2

Machine learning-based prediction of gaps in groundwater time series in the overburden of the Morsleben radioactive waste repository, Germany 

Tuong Vi Tran, Aaron Peche, Katrin Brömme, Robert Kringel, and Sven Altfelder

Understanding the movement of radionuclides over time is crucial for assessing the integrity of geological formations as barrier for a radionuclide waste repository. Long-term groundwater potential time series enable the modelling of flow and transport scenarios, which help to predict how radionuclides may migrate from the repository through the overburden into the biosphere, if the overburden as geological barrier should fail. The accuracy of numerical flow and transport models depend on the availability of reliable input data, such that long-term groundwater potential time series help to ensure that numerical flow and transport scenarios accurately represent the complex hydrogeological processes occurring over time.

However, in practice it is very common that, due to financial constraints, vandalism of measurement devices, and other logistical problems result in shorter and/or longer gaps in the ideally continuous groundwater monitoring time series. These gaps can significantly hinder the reliability and completeness of the dataset, making it challenging to perform accurate analyses.

In response to these challenges, we use machine-learning methods with monthly precipitation data from the German meteorological service (DWD), monthly groundwater recharge data generated from the hydrological model RUBINFLUX and continuous groundwater time series from state run monitoring wells as inputs to predict the missing gaps in the groundwater potential time series in the overburden of the radioactive waste repository Morsleben (ERAM).

This approach highlights the importance of continuity in the dataset for further studies, modelling, and safety assessments for radioactive waste repositories. Using machine learning techniques can help to reconstruct the missing data and provide a more comprehensive and continuous dataset for validating and calibrating numerical flow and transport models. 

 

References:

Bear, J., 1972. Dynamics of Fluids in Porous Media. American Elsevier, New York.

Langkutsch, U., Käbel, H., Margane, A., & Schwamm, G. (1998). Planfeststellungsverfahren zur Stillegung des Endlagers für radioaktive Abfälle Morsleben. 457. 

Peche, A., Kringel, R., Orilski, J., & Skiba, P. (2021). Hydrogeologische Modellbildung des ERA Morsleben. In Zwischenbericht Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) im Auftrag der Bundesgesellschaft für Endlagerung (BGE).

Hölting, B., & Coldewey, W. G. (2013). Hydrogeologie. In Hydrogeologie. Spektrum Akademischer Verlag. https://doi.org/10.1007/978-3-8274-2354-2

Zepp, H., König, C., Kranl, J., Becker, M., Werth, B., & Rathje, M. (2017). Implizite Berechnung der Grundwasserneubildung (RUBINFLUX) im instationären Grundwasserströmungsmodell SPRING. Eine neue Methodik für regionale, räumlich hochaufgelöste Anwendungen. Grundwasser, 22(2), 113–126. 
https://doi.org/10.1007/S00767-017-0354-3

How to cite: Tran, T. V., Peche, A., Brömme, K., Kringel, R., and Altfelder, S.: Machine learning-based prediction of gaps in groundwater time series in the overburden of the Morsleben radioactive waste repository, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17411, https://doi.org/10.5194/egusphere-egu24-17411, 2024.

EGU24-17828 | ECS | Posters on site | ERE3.2

Assessing microbial activity and survivability in heated and irradiated bentonite samples under deep geological repository relevant conditions 

Deepa Bartak, Šárka Šachlová, Vlastislav Kašpar, Jakub Říha, Petr Večerník, Veronika Hlaváčková, and Kateřina Černá

Bentonite is a crucial part of the engineered barrier system (EBS) of the deep geological repositories (DGR) for nuclear waste. However, as a natural material, it harbors diverse indigenous microorganisms whose metabolic activity might compromise the long-term integrity of EBS. One of the critical questions for microbial activity prediction in DGR is the microbial reaction to the early hot phase of nuclear waste repository evolution. Our study investigates the impact of gamma radiation and heat on microbial survivability in bentonite (Czech bentonite BCV and reference bentonite MX-80), considering variations in compaction, temperature, and saturation levels as these factors are known to influence microbial reaction to extreme conditions. Previous results suggested average radiation tolerance and high heat tolerance of indigenous bentonite microorganisms. We aimed to confirm these findings during the medium-term experiment (18 months) at the repository simulating conditions. Four experimental setups were conducted using compacted BCV and MX-80 bentonites under anoxic conditions differing in initial saturation level (15-20 wt. %), heating temperature ( 90 or 150°C), and irradiation (0.4 Gy/h). An additional set of bentonite powder samples heated at 90°C or 150°C for 1, 3, and 6 months was further included to unravel the time effect of heat exposure on microbial survivability. Microbial community analysis, involving natural incubations in the form of bentonite suspension, enrichment cultures, microscopy, and molecular methods, was conducted for each sample to estimate microorganism survival following exposure to extreme conditions.

Contrary to expectations, no microbial growth and recovery were detected in any treated samples except for the additional set. Fresh samples, suspension incubations, and enrichment cultures were checked negative for microbial presence in almost all the cases in the four main experimental sets except for the positive controls. On the other hand, the samples from the additional set showed microbial recovery after heating at 90°C for 1, 3, and 6 months. However, exposure to 150°C for only 1 month resulted in bentonite sterilization. These medium-term data pointed out the high tolerance of indigenous bentonite microorganisms to heat but also indicated that developing a sterile bentonite layer in the proximity of hot and radiation-emitting metal canister is highly likely at the early stage of the DGR evolution. However, the particular development will depend upon the DGR design and actual levels of temperatures and irradiation. To enhance our understanding and predictability of microbial processes in the bentonite sealing layer of DGRs for nuclear waste, further microbiological experiments simulating conditions in distant bentonite layers subjected to lower temperature and studying potential microorganism penetration from non-sterile to sterilized zones are needed.

How to cite: Bartak, D., Šachlová, Š., Kašpar, V., Říha, J., Večerník, P., Hlaváčková, V., and Černá, K.: Assessing microbial activity and survivability in heated and irradiated bentonite samples under deep geological repository relevant conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17828, https://doi.org/10.5194/egusphere-egu24-17828, 2024.

EGU24-18157 | ECS | Orals | ERE3.2

Visual observation of freezing and thawing processes in 3d printed fracture replicas 

Michael Kröhn and Klaus-Peter Kröhn

In the German site selection process for a nuclear waste repository, crystalline rock is one of three different types of host rock that are currently considered. As contact of groundwater with the waste canisters poses one of the main threats to such a repository, knowledge about groundwater flow in the general area is essential for a safety assessment. By law, the safety of a nuclear waste repository in Germany must be ensured for at least one million years. During this time, several ice ages are very likely to occur. They are expected to cause permafrost conditions in the underground at any conceivable location for a repository and are to be considered in the safety assessment as they are accompanied by considerable changes in groundwater flow due to freezing.

Freezing of water in a classic porous medium does not result in an instantaneous phase change of the whole pore water, though. Within a certain temperature range, an increasing volume of ice builds up in the pore space with falling temperatures. The referring Soil Freezing Characteristic Curve (SFCC) relates the degree of water/ice saturation with temperature thereby providing a key parameter for the temperature-dependent relative permeability. While these constitutive relations have already been investigated for classic porous media, hardly any information is available yet for fracture flow in crystalline rock. A new methodology has thus been developed for measuring the temperature-dependent relative permeability in fractures.

Based on a digital representation, a transparent fracture replica with a size of 7 by 10cm has been 3d printed. As groundwater flow in granite mainly occurs within the fractures, the influence of the rock matrix on such processes is neglected by the new method. To detect the formation of ice inside the fracture replica, a LED light source was placed underneath the fracture replica and freezing as well as melting processes were observed by a camera positioned above the fracture. The whole experimental setup was placed inside a climate chamber to test the influence of different temperatures. Before the tests, all components were tempered for at least 3 days before the system got completely flooded. The distinction between water as well as ice who are both transparent in their natural state was rendered possible by using a 0,05% methylene-blue solution. In a liquid state it is dark blue while being transparent in solid state. Pretesting ensured that the added methylene-blue has only a negligible effect on the freezing behavior. In parallel to observing visually the freezing and thawing in the fracture, the related effective permeability was determined by measuring the outflow rate at a constant inflow pressure.  

The obtained images were segmented using Matlab for evaluating the ratio between ice and liquid water. In combination with the performed flow tests, the relation between relative permeability and ice content has been determined for the printed fracture replica. Further tests with variations of the replica are envisioned.

How to cite: Kröhn, M. and Kröhn, K.-P.: Visual observation of freezing and thawing processes in 3d printed fracture replicas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18157, https://doi.org/10.5194/egusphere-egu24-18157, 2024.

EGU24-18345 | ECS | Posters on site | ERE3.2

Effect of gamma-irradiation on the surface and adsorption properties of bentonite clay 

Carla Soto Ruiz, Úrsula Alonso de los Ríos, Tiziana Missana, and Pedro Pablo Valdivieso Mayoral

Deep geological repository (DGR) is the best solution for confining high-level radioactive waste (HLRW). DGRs are multibarrier systems, where a metallic container of carbon steel or other metals is surrounded by a compacted bentonite barrier confining the waste, and placed in adequate geological formation. The purpose of DGRs is to delay the migration of radionuclides (RN) into the biosphere until the radiation was inoffensive.

Bentonite is a clay with high stability. Its durability depends on the physical, chemical, thermal and mechanical conditions of the repository and may be affected by the radiation emitted by the waste.

The objective of this research is to compare the surface properties of gamma-irradiated and unirradiated bentonite (Ca-Mg FEBEX bentonite) to evaluate if the irradiation from the radioactive waste encapsulated in the metallic container modifies.

To evaluate the effect of the accumulated dose, the bentonite was subjected to two rounds of irradiations during 9 days with a 60Co source in pool like installation achieving cumulative gamma doses of 14 kGy and 140 kGy.

The structural characteristics of irradiated and unirradiated bentonite samples are analysed by infrared spectroscopy [1] to identify changes in functional groups of the clays. Zeta potential measurements as well as potentiometric titrations to obtain information on the density of SOH hydroxyl surface groups on the edges of clay particles. All these properties are essential for the adsorption capacity of the material.

Lastly, the sorption capacity of irradiated bentonite was evaluated by measuring Sr and Se sorption isotherms at fixed pH and ionic strength conditions, representative elements with different sorption mechanism on bentonite, to be compared to the unirradiated bentonite [2], [3].

Results showed that the analysed properties were slightly affected by gamma-irradiation in the doses investigated.

 

 

ACKNOWLEDGEMENTS: The authors would like to thank the finance of this research to the CIEMAT predoctoral fellowship (209-PRECIE-PDE22) through the European Union Project, EURAD-WP ConCorD, Grant Agreement no. 847593.

 

REFERENCES

 

[1] Madejova, J., Komadel, P. 2001. Baseline studies of the clay minerals society source clays: infrared methods. Clays and clay minerals, 49(5), 410-432.

[2] Mayordomo, N., Alonso, U., & Missana, T. (2016). Analysis of the improvement of selenite retention in smectite by adding alumina nanoparticles. Science of The Total Environment, 572, 1025-1032.

[3] Missana, T., Garcia-Gutierrez, M., & Alonso, U. (2008). Sorption of strontium onto illite/smectite mixed clays. Physics and Chemistry of the Earth, Parts A/B/C, 33, S156-S162.

How to cite: Soto Ruiz, C., Alonso de los Ríos, Ú., Missana, T., and Valdivieso Mayoral, P. P.: Effect of gamma-irradiation on the surface and adsorption properties of bentonite clay, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18345, https://doi.org/10.5194/egusphere-egu24-18345, 2024.

In this contribution we have developed a reactive transport model to assess the hydro-chemical evolution of a L-ILW disposal cell in indurated clay rocks, involving the interaction of different components/materials and the expected hydraulic and/or chemical gradients over 100 000 years. The L-ILW disposal cell leverages a multi-barrier concept buried between 200 and 800 m below the surface. The multi-barrier system is comprised of the waste matrix (i.e. backfilling the waste drums), the disposal container, the mortar backfill in the emplacement tunnel (where the disposal containers are located) and the clay host rock. The dimensions and design of the emplacement tunnel (e.g. 11 × 13 m) and disposal cells represent and consider some aspects taken into account in the designs of some European countries. In addition, tunnel walls reinforced with a shotcrete liner and the Excavation Damaged Zone is considered in the concept. The model is implemented in OpenGeoSys-6, an open-source version-controlled scientific software based on Finite Element Method which is capable of handling fully coupled hydro-chemical models by coupling OpenGeoSys to iPHREEQC. First calculation results, demonstrate that the most important processes affecting the near-field chemical evolution are i) the degradation of the concrete and cementitious grouts with porewater migrating inwards from the host rock and ii) the significant quantities of reactive and non-reactive gases (i.e. hydrogen, carbon dioxide and methane) that are generated as a result of: i) the anaerobic corrosion of metals present in the waste and containers and ii) the degradation of organic compounds by microbial and chemical processes. Several simulation cases were carried out under different assumptions, specially related to the saturation of the domain, the final goal was to have a 2D model of the system representing a more realistic geometry which will potentially help in design optimization decisions.

How to cite: Montoya, V. and Garibay-Rodriguez, J.: 2D reactive transport model for assessing the chemical evolution of a low and intermediate-level waste repository in clayrock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18849, https://doi.org/10.5194/egusphere-egu24-18849, 2024.

EGU24-19338 | ECS | Posters on site | ERE3.2 | Highlight

Geochemical composition of sandstone samples from drill cores of the former uranium ore mine Königstein (Saxony) and the determination of hydrochemical equilibrium concentrations of uranium by means of batch tests 

Sebastian Schramm, Ferry Schiperski, Mathias Hübschmann, Frank Horna, and Traugott Scheytt

Geochemical background values are commonly used for the authorization of remediation measures. However, in the case of the former Königstein uranium ore mine, located in Saxony (Germany), natural uranium concentrations in groundwater cannot be directly assessed, due to active mining activities. The Königstein uranium ore depositis located within the 4th aquifer and consists of the Oberhäslich Formation and 'Wurm'-Sandstone.

This study aimed at deriving natural uranium content using batch shake test, assuming chemical equilibrium with regard to the speciation of uranium in solution and the binding to the rock matrix. For that purpose, representative subsamples from core material were taken for batch experiments and geochemical analyses. As uranium solubility strongly dependents on the redox state, the pH value, and the hydrochemistry of the target fluid, experiments were performed under various conditions.

The rock samples were analyzed with respect to geochemical and mineralogical compositions, while uranium concentration in fluid samples was measured using inductively coupled plasma - mass spectrometry. Concentrations of major cations were analyzed using cation chromatography techniques. The PHREEQC software was used to analyses the species distribution of uranium under the hydrochemical conditions of the the unaffected inflowing water from the inflow area.

Results show, that the sandstones in the middle of the 4th aquifer consist mainly of SiO2 with more than 98 wt.-%. Two-layer clay minerals and iron oxides were identified in another sample with fractions more than 50 wt.-% kaolinite. Uranium was found in the anaerobic zone in one rock sample at 1820 ppm and once at only 25.6 ppm.

Equilibrium modeling revealed, that at a pH of 5.5 to 6 and under oxidizing conditions, uranium mainly occurs as UO22+, UO2OH+, and UO2CO3. It can therefore be expected that the uranium species present as cations will likely be adsorbed by the solid matrix. Initial shaking tests showed that combining reduced rock materials with oxidizing water led to excessive uranium fractionation into the fluid phase. Batch tests using deionised water showed uranium concentrations between 2 and 2.5 mg/l, contrasting expectation of natural uranium concentrations in the lower µg/l range.

How to cite: Schramm, S., Schiperski, F., Hübschmann, M., Horna, F., and Scheytt, T.: Geochemical composition of sandstone samples from drill cores of the former uranium ore mine Königstein (Saxony) and the determination of hydrochemical equilibrium concentrations of uranium by means of batch tests, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19338, https://doi.org/10.5194/egusphere-egu24-19338, 2024.

Climate evolution over millennial timescales significantly influences various environmental aspects, including thermal conditions, regional sea levels, geomorphological evolution, weathering processes, and hydrogeological evolution. This intricate relationship has direct implications for nuclear waste management facilities, as climate change alters the frequency and intensity of extreme events, posing risks during construction, operation, and post-closure phases. Understanding these impacts is crucial for ensuring safety and to building civil society's confidence in radioactive waste management programes. This contribution centers on Belgian scenarios.

SCK CEN, with extensive experience in studying climate change impacts on nuclear waste management, shares its insights from projects such as BIOCLIM, BIOMOSA, and EURAD. The Belgian case, with its diverse climate regions, offers valuable data applicable to other countries facing similar climate challenges. For example, SCK CEN's involvement in EURAD - UMAN has already prompted recommendations for managing uncertainties in the geosphere, particularly in climatic evolution. Key areas of focus could include validating permafrost depth models, modeling hydrochemical changes resulting from permafrost development, conducting detailed palaeo-hydrological studies, and considering the influence of decompaction on host rock properties. This study serves as a critical resource for understanding and addressing climate-related challenges in nuclear waste management, fostering international collaboration and knowledge exchange.

How to cite: Montoya, V. and Beerten, K.: Climate Change Impacts on Nuclear Waste Management: Insights from Belgium and Recommendations for Future Research, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19823, https://doi.org/10.5194/egusphere-egu24-19823, 2024.

EGU24-21252 | Posters on site | ERE3.2

New underground research facility for deep disposal of radioactive waste Bukov II, Czech Republic: objectives, geological constraints and current status 

Lucie Mareda, Igor Soejono, Zita Bukovská, Ondřej Švagera, Lenka Rukavičková, Jaroslav Řihošek, Jakub Kry, Tereza Zelinková, Tomáš Chabr, Radek Morávek, Kamil Souček, Martin Vavro, Petr Waclawik, Karel Sosna, Jiří Nedvěd, Lukáš Mareček, and Anna Macáková

​In order to place experiments in real geological conditions, a new section of the already active generic underground research facility Bukov (Bukovská et al. 2019) is recently being constructed. It is located in the central Bohemian Massif, in former uranium mine Rožná, at c. 550 m below the surface. During the excavation of new tunnels and laboratory chambers, a complex of geomechanical, structural, geological, hydrogeological and geophysical measurements and monitoring activities is continuously performed. The main objectives of this in-situ characterization project are to understand and 3D visualize the structural record and its hydrogeological systematics. Other objectives are to determine the excavation damage zones, the effect of blasting, the physical and mechanical properties of the rocks, and testing the excavation and drilling methodology.

The laboratory is situated mostly in the intensively deformed paragneiss, high-grade amphibolites and migmatites, typical for the European Variscan belt. Geological observations have revealed a complex polyphase deformational pattern of metamorphic foliations, strongly influencing the superposed fault and fracture systems, hydrogeological conditions and rock mass properties. Based on multidisciplinary research of borehole and tunnel data, possible problematical geological structures are identified and investigated. Finally, all obtained data and experience will serve to development of work-flows of documentation and rock-mass suitability classification system during building of the future real deep geological repository.

The construction will be completed in 2024 and the underground research facility will become part of the national planning and siting strategy for the deep underground repository for high-level radioactive waste. The data from this research will contribute to the understanding of the geology of the region and will be used for experiments addressing long-term safety and technical feasibility. Such results from the depth can allow correlation and validation of data collected from surface research (Soejono et al. 2021) in the potential sites for deep geological repository construction.

 Bukovská, Z., Soejono, I., Vondrovic, L., et al., 2019. Characterization and 3D visualization of underground research facility for deep geological repository experiments: A case study of underground research facility Bukov. Czech Republic. Eng. Geol. 259, 105186. https://doi.org/10.1016/j.enggeo.2019.105186

Soejono, I., Bukovská, Z., Levá, B., et al., 2021. Interdisciplinary geoscientific approach to radioactive waste repository site selection: the Březový potok site, southwestern Czech Republic. J. Maps 17, 741–749. https://doi.org/10.1080/17445647.2021.2004942

How to cite: Mareda, L., Soejono, I., Bukovská, Z., Švagera, O., Rukavičková, L., Řihošek, J., Kry, J., Zelinková, T., Chabr, T., Morávek, R., Souček, K., Vavro, M., Waclawik, P., Sosna, K., Nedvěd, J., Mareček, L., and Macáková, A.: New underground research facility for deep disposal of radioactive waste Bukov II, Czech Republic: objectives, geological constraints and current status, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21252, https://doi.org/10.5194/egusphere-egu24-21252, 2024.

EGU24-21286 | Posters on site | ERE3.2

EURAD ACED – Modelling the geochemical evolution of disposal cells in deep geological repositories 

Diederik Jacques and Vanessa Montoya and the EURAD - ACED Team:

The European Union’s Horizon 2020 project EURAD (European Joint Progamme on Radioactive Waste Management) aim is to implement a joint Strategic Programme of research and knowledge management activities at the European level, bringing together and complementing EU Member State programmes in order to ensure cutting-edge knowledge creation and preservation in view of delivering safe, sustainable and publicly acceptable solutions for the management of radioactive waste across Europe now and in the future. The broader scope of the work package ACED (Assessment of the chemical evolution in intermediate and high level radioactive waste disposal cells) in EURAD is the assessment of the chemical evolution at the disposal cell scale involving interacting components/materials and thermal, hydraulic and/or chemical gradients. Four generic disposal cells that are representative for the most important aspects of disposal designs in several national disposal programs throughout Europe, formed the basis for the research activities in this work package.

Conceptual, mathematical and numerical models were developed and implemented to describe the geochemical evolution in the combined engineered barrier system and the immediately surrounding host formation (clay or granite) from a more detailed scale up to a spatial scale of a few meters and time scales up to 100 000 y. ACED demonstrated the applicability of advanced coupled reactive transport models to provide an integrated view on coupled geochemical processes in the multi-barrier system of a deep geological repository. Insight in the geochemical evolution was obtained from more detailed numerical models at the scale of the waste package (neglecting influences from the host rock) up to models with the detailed geometry and the different materials in the disposal scale (depending on the system including nuclear glass, organic waste, metallic waste, steel, cementitious materials, bentonite, and host rock). Beside models that integrated as detailed as possible the available information, approaches were tested to decrease the model complexity while preserving the key findings of the more complex models; a process also known as model abstraction. Simplifications were made with respect to dimensionality, chemical complexity and numerical accuracy as well by implementing surrogate models based on machine learning tools to replace the parts of the models requiring the most computational time.

ACED made a significant step forward in process-based modelling of geochemical interactions  in the near field of a geological repository where the engineered barrier system interacts with the host rock. The models and insights obtained for the generic disposal cells can form a basis for more specific research studies in national disposal programs.

Acknowledgement: The research leading to these results was funded by the EURAD work package (European Joint Programme on Radioactive Waste Management of the European Union, EC grant agreement nº 847593)

How to cite: Jacques, D. and Montoya, V. and the EURAD - ACED Team:: EURAD ACED – Modelling the geochemical evolution of disposal cells in deep geological repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21286, https://doi.org/10.5194/egusphere-egu24-21286, 2024.

EGU24-1685 | Posters on site | ERE3.3

Determination of Seismic Velocities in Bentonite Backfill Through Ultrasonic Measurements in the FE-Experiment 

Monika Sobiesiak, Katrin Plenkers, Thomas Fischer, Edgar Manukyan, and Thomas Spillmann

One important aspect of implementation of deep underground radioactive waste repositories is the physical characterization of backfill material which fills the voids between waste containers and ambient host rock. The Mont Terri Rock Laboratory, located in NW Switzerland and operated by swisstopo, is an international subterranean research facility which offers a perfect environment to carry out experimental test phases on such barrier systems. In this study, we report on eight years of ultrasonic monitoring in the bentonite backfill of the FE-Experiment, which aims at monitoring long-term changes in material properties of the backfill around a simulated radioactive waste repository under the conditions of rising temperature and increasing humidity. The FE Experiment is a full-scale heater test in the Opalinus clay. It simulates the construction, waste emplacement, backfilling and early post-closure evolution of spent fuel (SF)/vitrified high level waste (HLW) repository tunnel (Mueller et al., 2017).

 

The monitoring method is based on the generation of seismic signals in the frequency range of 1000 Hz to 100 kHz emitted and received by acoustic sensors. In total, 17 sensors (4 emitters and 13 receivers) manufactured by GmuG, form two different arrays. One is a permanent array installed within the bentonite material itself, responsible for measuring the ultrasonic transmission on a cross section through the tunnel in front of the heater closest to the concrete plug that closes the tunnel. The second array is installed within plexiglass pipes that were mounted in the roof area of FE tunnel and reach beyond the same cylindrical heater. Each night, from 22:00 to 06:00 the next morning, repeated delta signals are generated by the emitters and the respective wavefields are recorded by the receiving sensors.

 

The P and S phase first arrivals of the stacked waveforms are used then to estimate seismic velocities. The ongoing experiment is a unique longterm observation of the process within the bentonite. We show that, besides a general increase in velocities over time, the measurements resolve distinct differences in various areas within the backfill. For a ray path on the cross section, the P-wave velocity increased by approximately 100 m/s, from 550 m/s in 2015 to 642 m/s in 2023. Dividing the monitored area into the different sections, we find that seismic velocities in the floor area of the tunnel show higher values than in the roof area. Considering the entire wavefields at each sensor over time, we observe strong changes in waveform characteristics by disappearing of entire phases or changes in amplitudes. All observations reflect changes in material properties over time. The reasons for different seismic velocities in roof and floor area of the tunnel might lie in the graveled texture and swelling of particles due to increasing humidity and/or in a compaction process which is faster at the bottom of the tunnel. The process of velocity increase in the bentonite backfill is still ongoing at most of the emitter – receiver combinations.

 

How to cite: Sobiesiak, M., Plenkers, K., Fischer, T., Manukyan, E., and Spillmann, T.: Determination of Seismic Velocities in Bentonite Backfill Through Ultrasonic Measurements in the FE-Experiment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1685, https://doi.org/10.5194/egusphere-egu24-1685, 2024.

EGU24-2049 | Orals | ERE3.3 | Highlight

Impact of glacially induced stresses and strains at Canadian candidate sites for nuclear waste disposal 

Holger Steffen and Rebekka Steffen

Continental-scale glaciations lead to deformation, geopotential, rotation, and stress changes of the Earth. Especially glacially induced stress changes in the lithosphere can significantly impact potential nuclear waste repository sites, planned for depths a few hundred meters below ground. Ensuring the long-term stability of these sites warrants analyzing such additional stresses in the crust that might be imposed by future ice sheets during forthcoming glaciations. We focus on North America by investigating the past to quantify such stresses.

Utilizing a refined, high-resolution North American ice history spanning 122,000 years from the University of Toronto Glacial Systems Model, alongside various one- and three-dimensional earth structures, we investigate the dynamic nature of glacially induced stresses at Canada’s candidate sites South Bruce and Ignace. Both sites are situated in Ontario but 1000 km apart. Additionally, we examine the corresponding deformation and strain changes.

We find that both sites undergo strong variations in glacially induced stresses and strains over a glacial cycle. Especially the horizontal components can change from tensional to compressive within a few thousand years due to fluctuations in ice cover. Surprisingly, despite South Bruce's location farther from the ice sheet center and its temporary position in the forebulge of the ice sheet, stress and strain magnitudes resemble those of Ignace. Moreover, there's potential at South Bruce for altering the direction of pre-existing maximum horizontal stress. Interestingly, the choice of earth structure in the modelling affects strain more than stress.

Although the sites are 1000 km apart, our results do not indicate a superior repository site. Instead, they emphasize the need to integrate our findings into the site selection process and barrier integrity assessment. We recommend further studies focusing on a stress analysis with more detailed earth models, considering faults and lineaments near the candidate sites.

This research was funded by the Nuclear Waste Management Organization, Canada.

How to cite: Steffen, H. and Steffen, R.: Impact of glacially induced stresses and strains at Canadian candidate sites for nuclear waste disposal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2049, https://doi.org/10.5194/egusphere-egu24-2049, 2024.

The United States initiated the Spent Fuel and Waste Storage and Transport (SFWST) Campaign over ten years to evaluate various generic geological repositories for the disposal of spent nuclear fuel. Most previous international work describes Engineered Barrier Systems (EBS) for repositories focused on low temperature conditions. Our hydrothermal experiments on EBS materials were conducted to characterize high temperature interactions of bentonite clay and argillite wall rock +/- cement with candidate waste container steels (304SS, 316SS, low-C steel).

Over eight years of hydrothermal experiments were performed using Dickson reaction cells at temperatures ranging from 150 to 300°C and pressures of 15 – 16 MPa, respectively, for five to eight weeks. Wyoming bentonite was saturated with a 1,900 ppm K-Ca-Na-Cl solution in combination with stainless and low-C steel coupons to replicate EBS conditions in deep geological disposition of nuclear spent fuel. The solid-reaction products and steel coupons were characterized post experiment via XRD, XRF, SEM, and EMP.

Preliminary mineralogic phase transformations for the experiments are as follows: Smectite clays did not transition to illite,. Clinoptilolite, appears to have formed from the remnant glass which was present in the original bentonite. The Si/Al ratios for the clinoptilolite are dominantly between 4 and 6. The Na/(Na+Ca) values range from 0.55 to 0.75. Calcite and gypsum were also observed as minor reaction products. Aqueous SiO2 remains saturated with respect to quartz throughout the experiments.

Our experiments focused on bentonite-cement interactions, including 1) Baseline bentonite stability in argillite, 2) reactions with Uncured OPC powder, 3) Cured OPC chip, and 4) Low-pH cement chips. In the Opalinus Clay, Wyoming bentonite + OPC powder experiments (#2), spherical, calcium aluminum silicate hydrate (CASH) phases formed within the fine-grained clay matrix. Based on the composition of this mineral, the C(A)SH phases are likely a hydrated calcium silicate, such as Al-tobermorite (Ca4.3Si5.5Al 0.5O16(OH)2•4(H2O)). Very Ca-rich hydrous minerals, such as Al-tobermorite, have been observed in experiments involving bentonite and cement with highly alkaline bulk chemistries and pH > ~10 (Savage et al., 2007).

 

The formation of CASH minerals contrasts with the products of previous experiments with Wyoming Bentonite ± Opalinus Clay host rock (#1), in which zeolites (analcime–wairakite solid solution) formed that have similar morphologies and textural contexts.

 

The experiments with cured OPC chips (#3) resulted in Portlandite dissolution during the early elevated pH values, but pH values stabilize at near-neutral values by equilibrium. Montmorillonite was stable, and zeolite formation was observed throughout the groundmass of the reaction products but was not abundant at the bentonite-cement interface. Reactions between the groundwater solution, bentonite, and the low-pH cement (#4) resulted in a lower steady-state silica concentration than reactions between groundwater solution, bentonite, low-pH cement, and Opalinus Clay wall rock. This suggests a controlling input on silica concentrations is affected by Opalinus Clay wall rock that is not advanced by the bentonite or low-pH cement alone.

 

How to cite: Caporuscio, F., Rock, M., and Zandanel, A.:  Argillite Host Rock and Cement - Engineered Barrier System Experiments: Mineralogical Evolution at Repository Pressures and Temperatures., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3238, https://doi.org/10.5194/egusphere-egu24-3238, 2024.

With nuclear energy being one of the trending topics in the world regarding energy supply, at the same time the question for safe disposal of the high-level radioactive waste becomes increasingly popular in the public. 

The TU Bergakademie Freiberg wants to provide answers to this challenging task by practical big-scale in-situ underground tests and new backfill material development. The underground mining chair commenced the GESAV (Gefügestabilisierter Salzgrusversatz; engl.: Matrix-stabilized salt grit backfill) project series back in 2013 with the development of a matrix-stabilized salt backfill which solidifies in an early stage by the development of internal polyhalite crystals. The innovative material combines the benefits of a salt backfill material with a stability compared to conventional materials, such as cement like building materials.

The GESAV project series has been finished in 2021 with the successful proof of the big-scale practical applicability of the matrix-stabilized backfill by building several backfill bodies underground with different methods from the conventional underground mining industry.

The goal for the currently going-on SAVER (Entwicklung eines salzgrusbasierten Versatzkonzeptes unter der Option Rückholbarkeit; engl.: Development of a salt grit based backfilling concept with regards to retrievability) project is to build and compare a GESAV material backfill body to a conventional salt backfill body, since in the GESAV II project only the in-situ applicability of the GESAV material in general has been researched. Both of the test drifts in the Sondershausen rock salt underground mine have the same dimensions and are instrumented exactly the same. Moreover, a radioactive waste casket dummy has been developed within the project and placed into the backfill bodies in order to simulate a real-life backfilling process. So far, both backfill bodies have been built with a slinger-vibration-backfill method that already highlighted very high in-situ densities in the GESAV II project (2017-2021). Not only did this validate the applicability of the method on GESAV material but also proved that it is transferable to other salt backfill materials.

During the building process of both bodies, a big sampling campaign was carried out in order to gain an insight into actual possible built-in in-situ densities and other parameters that are relevant for further optimization and understanding of real-life backfilling in a mining scale. Once analyzed, the samples, in combination with the other sensors, can provide a deep insight and further understanding of the geochemical and mechanical properties of both backfill bodies. The sensor data shows that GESAV material highlights better properties regarding settlement than conventional salt grit as well as pressure distribution within the backfill body. The measurement systems will continue to run as long as the project is taking place in order to continuously gain an insight into ongoing processes within both backfill bodies. With the chosen sensor setup as well as the sampling regime it is expected to gain more valuable insights into actual underground in-situ behavior of those materials in the near future. Those insights are very likely to contribute to the ongoing question of developing a feasible concept for high-radioactive waste disposal in rock salt formations.

How to cite: Schaarschmidt, L. and Mischo, H.: Big Scale In-Situ Application of Matrix-stabilized vs. Conventional Salt Grit Backfill with Use of Improved Backfilling Method, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3566, https://doi.org/10.5194/egusphere-egu24-3566, 2024.

EGU24-3647 | Orals | ERE3.3 | Highlight

Overview of the DECOVALEX Initiative - Building Confidence Via Model Comparison 

Jens Birkholzer and Alex Bond

Here we provide an overview of an international research collaboration for advancing the understanding and modeling of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems. The creation of the international DECOVALEX Initiative, now running for more than 30 years, was motivated by the recognition that prediction of these coupled effects is an essential part of demonstrating the performance and safety of radioactive waste disposal and other subsurface engineering applications. DECOVALEX emphasizes joint analysis and comparative modeling of state-of-the-art field and laboratory experiments, across a range of host rock options and repository designs. Participating research teams are from radioactive waste management and other organizations, national research institutes, regulatory agencies, universities, as well as industry and consulting groups, providing a wide range of perspectives and solutions to these complex problems. The most recent phase of the initiative, referred to as DECOVALEX-2023, started in 2020 and ended in December 2023. Modeling teams from 17 international partner organizations participated in the comparative evaluation of seven modeling tasks involving complex experimental and modeling challenges. The presentation provides examples of research contributions made within DECOVALEX-2023 and illustrates how these have helped building confidence in long-term performance predictions. These examples range from the modeling of large-scale in situ heater tests representing mock-ups of nuclear waste disposal tunnels, the analysis of gas transport tests in clay-based materials, the prediction thermal and gas pressure rock fracturing, to the comparison of performance assessment models.

The main characteristic of DECOVALEX is the close collaboration on analyzing and simulating state-of-the-art field and laboratory experiments, which provides a wide range of experiences, perspectives and solutions to these complex problems and allows for detailed comparison of analysis and modeling results. Much insight can be gained through this cooperative comparison of results from different research teams using different model approaches, not only on the effects of complex THMC processes, but also on the strengths, weaknesses, and adequacies of the various approaches and predictive models used by these research teams. We make the case in this presentation that DECOVALEX has contributed, and continues to contribute, to enhancing confidence in the technical adequacy of radioactive waste disposal, by improving our collective understanding of complex subsurface perturbations and coupled processes, by developing and comparing predictive models for these processes, by evaluating their uncertainties, by recognizing areas for additional research, and by emphasizing means of learning from each other and knowledge sharing. The insight and scientific knowledge gained would not have been possible if individual groups had studied these data alone rather than within a truly collaborative setting.

How to cite: Birkholzer, J. and Bond, A.: Overview of the DECOVALEX Initiative - Building Confidence Via Model Comparison, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3647, https://doi.org/10.5194/egusphere-egu24-3647, 2024.

EGU24-4976 | ECS | Orals | ERE3.3

Three-dimensional characterization of an excavation-induced fracture network with gas tomography 

Lisa Maria Ringel, Rémi de la Vaissière, Ralf Brauchler, and Peter Bayer

In the safety assessment of a nuclear waste repository, it is crucial to identify and isolate possible pathways for radionuclides from the waste canister to the biosphere and vice versa. Despite the potential self-sealing properties depending on the host rock and the decrease of the permeability over time, the migration depends on the presence of a fracture network, the connectivity of the fractures, and their connectivity to tunnels or drifts. To describe the initial state of said pathways, we demonstrate the inversion of transient pressure measurements to delineate the structural and pneumatic properties of an excavation-induced fracture network at the Meuse/Haute-Marne Underground Research Laboratory (URL) operated by the French radioactive waste management agency ANDRA.

The tomographic tests were carried out as sequential constant-rate injections of nitrogen and the resulting pressure perturbations were recorded in nearby borehole intervals. In total, nine boreholes with two injection/monitoring intervals each are available on a volume of approximately 3m times 3m times 5m. Therefore, the joint inversion of more than 300 signals allows unique insights into the excavation-induced fracture network.

A discrete fracture network (DFN) model is applied for the forward and inverse modeling. Thereby, the strong heterogeneity of the distribution of hydraulic or pneumatic properties caused by the fracture network can be described. A numerical model is used to simulate the transient pressure diffusion in the DFN. The structural properties and the permeability of the DFN model are characterized by solving the inverse problem. The inversion relies on a stochastic model of the DFN parameters based on the Bayesian equation. The posterior distribution, i.e., the distribution of the DFN parameters given the measured data, is the product of likelihood and prior distribution. The likelihood function compares the error between the measured data and the simulated outcome of the tomography experiments for a given DFN model. The prior distribution includes information about the fracture properties obtained in previous studies. The posterior distribution is characterized by generating samples from the posterior with Markov chain Monte Carlo (MCMC) methods. Due to the unknown number of fractures, the insertion and deletion of fractures are possible according to the reversible jump MCMC algorithm.

The inversion approach results in several DFN realizations that are approximately equally likely which is illustrated in a fracture probability map and a map of the permeability distribution. Thereby, preferential flow paths can be characterized.

How to cite: Ringel, L. M., de la Vaissière, R., Brauchler, R., and Bayer, P.: Three-dimensional characterization of an excavation-induced fracture network with gas tomography, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4976, https://doi.org/10.5194/egusphere-egu24-4976, 2024.

Pore pressure evolution and hydraulic flow are two important physical features to consider in barrier integrity and radionuclide transport applications. Existing literature suggests a potentially non-negligible impact of thermo-osmosis on pore-pressure evolution due to thermal gradients in clay rocks without arriving at a consensus. Numerical experiments based on models are a widely used method in the geosciences to test the relevance of physical features under specified conditions. Mismatch between the observations and the simulation can be partially attributed to the assumptions and simplifications made when developing those models. Their impact on the results and conclusions drawn from the numerical experiments can be significant and thus needs to be explored. Such exploration can proceed by jointly investigating the uncertainty associated with modelling choices, process selection and calibration. This study applies a hypothesis-testing method based on an assisted-history-matching workflow to integrate uncertainty evaluation of model selection, process representation and parameter identification. Three models were compared, representing, respectively, the correct, approximate and wrong hypotheses with respect to a synthetic data set resembling the ATLAS experiment, an in-situ, full-scale heating experiment performed at the HADES underground laboratory in Mol, Belgium. We show that the approach can recover the correct modelling hypothesis in the presence of parameter uncertainty despite competing hypothesis with the same amount of parametric degrees of freedom.

How to cite: Kiszkurno, F., Buchwald, J., Kolditz, O., and Nagel, T.: Hypothesis-testing and assisted-history-matching applied to evaluate uncertainty of model selection and parameter values: a case study of the impact of thermo-osmosis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6012, https://doi.org/10.5194/egusphere-egu24-6012, 2024.

EGU24-6036 | Posters on site | ERE3.3

Validation and benchmarking of simplified reactive transport models of radionuclides for the assessment of nuclear waste repositories 

Haibing Shao, Philipp Selzer, Christoph Behrens, Christoph Lehmann, Phillip Kreye, Wolfram Rühaak, and Olaf Kolditz

Finding the best-suited location for safely storing high-level nuclear waste is more than a scientific challenge for a country. In Germany, the legal requirements demand a safe containment of high-level nuclear waste for at least one million years within a deep geological repository. In this context, the site selection procedure demands a validated model to predict the reactive transport of radionuclides in layered subsurface formations with varying physical and chemical properties. In this work, we compare the modelling capabilities of TransPyREnd, which is a one-dimensional transport code based on finite differences, especially developed for the quick estimation of radionuclide transport, with an established geoscientific simulator OpenGeoSys, which is capable of coupled thermo-hydro-mechanical-chemical modelling based on finite elements in three spatial dimensions. Both codes are going to be used in the site selection procedure for the German nuclear waste repository. The example host rock formation for benchmarking is the Opalinus clay located in southern Germany, which is modelled using a simplified and preliminary parametrization. We enhance the validation analysis by also benchmarking against an analytical solution for a homogeneous material. The modelling results suggest that both TransPyREnd and OpenGeoSys are capable of consistently modelling the distribution of radionuclides within the geological barrier over long timescale. The discussion further goes to the applicability of different approaches for serving as tools in the site selection procedure, with minor differences in their predictive capabilities, limitations, and possible pitfalls to be avoided for the accurate prediction of radionuclide transport over geological times.

How to cite: Shao, H., Selzer, P., Behrens, C., Lehmann, C., Kreye, P., Rühaak, W., and Kolditz, O.: Validation and benchmarking of simplified reactive transport models of radionuclides for the assessment of nuclear waste repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6036, https://doi.org/10.5194/egusphere-egu24-6036, 2024.

EGU24-6051 | Posters on site | ERE3.3

Effects of glacial isostatic adjustment on fault reactivation and its consequences on radionuclide migration in crystalline host rock 

Dominik Kern, Fabien Magri, Holger Steffen, and Thomas Nagel

Deep geological repositories (DGRs) are designed to isolate radioactive waste (RW) from the biosphere over extremely long-time scales (i.e., several hundred thousand years). In order to assess the robustness of a safety case for a DGR, it is therefore necessary to analyse probable, less probable and hypothetical future developments due to, for example, climate change. Climate models predict that several ice sheets will advance and retreat over the next several thousands years. Glacial isostatic adjustment (GIA), resulting from the large moving mass of an ice sheet, can alter the displacement and far-field stress field of a DGR.

Due to their extremely low matrix permeability, crystalline rocks are suitable host rocks for the disposal of RW in DGRs. However, the mechanical properties of crystalline rocks often promote crack growth and faulting, which in turn compromise their barrier function with respect to groundwater flow. In the INFRA project (DFG NA1528/2-1 and MA4450/5-1), we quantify how faults prone to reactivation during glacial events can affect radionuclide migration around a DGR in crystalline rock.

We apply boundary conditions derived from an established GIA model [1,2] to a finite element model [3,4] of coupled fluid flow and radionuclide transport to numerically solve the component transport problem before and after fault reactivation. The Coulomb failure stress criterion is used as an indicator of permeability changes. The simulations show that GIA can increase permeability in the upper 400m of the reactivated faults. There, groundwater flow enhances radionuclide migration along the fault. In contrast, groundwater flow is reduced in the direction perpendicular to the fault plane. Although the proposed numerical workflow has been applied to the case of GIA, it can also be adapted to study hydromechanical processes induced by seismic events or by hydrofracking in enhanced geothermal systems.

 

[1] Argus, D.F., Peltier, W.R., Drummond, R., Moore, A.W.: The Antarctica component of postglacial rebound model ICE-6G C (VM5a) based on GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories. Geophysical Journal International 198(1), 537–563 (2014)
https://doi.org/10.1093/gji/ggu140

[2] Peltier, W.R., Argus, D.F., Drummond, R.: Space geodesy constrains ice age terminal deglaciation: The global model. Journal of Geophysical Research: Solid Earth 120(1), 450–487 (2015)
https://doi.org/10.1002/2014JB011176

[3] Bilke, L., Flemisch, B., Kalbacher, T., Kolditz, O., Helmig, R., Nagel, T.: Development of Open-Source Porous Media Simulators: Principles and Experiences. Transport in Porous Media 130(1), 337–361 (2019)
https://doi.org/10.1007/s11242-019-01310-1

[4] Bilke, L., Fischer, T., Naumov, D., Lehmann, C., Wang, W., Lu, R., Meng, B., Rink, K., Grunwald, N., Buchwald, J., Silbermann, C., Habel, R., Günther, L., Mollaali, M., Meisel, T., Randow, J., Einspänner, S., Shao, H., Kurgyis, K., Kolditz, O., Garibay, J.: OpenGeoSys. Zenodo (2022)
https://doi.org/10.5281/zenodo.7092676

How to cite: Kern, D., Magri, F., Steffen, H., and Nagel, T.: Effects of glacial isostatic adjustment on fault reactivation and its consequences on radionuclide migration in crystalline host rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6051, https://doi.org/10.5194/egusphere-egu24-6051, 2024.

Dealing with a complex sociotechnical system such as radioactive waste disposal needs an integrated perspective. Much of the widespread blockage faced hitherto may be ascribed to the neglect of relevant dimensions involved. Normatively, the principle of sustainability (incorporating passive protection and control) suggests itself as a reference system. It facilitates a stepwise analysis of dimensions: not only the conventional triad of ecological, economical, and social but also temporal, spatial, technical, political, and ethical. It forces upon stakeholders, including decision makers, an examination of these dimensions and is apt to incorporate most parties’ perspectives, needs, goals, and knowledge systems. After all, we need safe as well as acceptable and accepted sites with facilities designed, built, operated and sustainably closed in due time.

Long-term management of highly toxic waste epitomises three central distributional issues: - local cost and risk vs. general benefit (intragenerational equity issue), - lay persons’ vs. experts’ perspectives (evidentiary equity), - today’s vs. future generations (intergenerational equity). The long-term (ecological) waste dimension is of outstanding ethical relevance: The ones who make the profit (e.g., energy incurring waste) most likely do not bear – possible – risks from the waste. Still, the current generations (we!) have to decide (postponement is also a decision), and: Apart of winners (this waste producing society) there will be losers (locals and future generations). A formidable risk-benefit asymmetry.

Against this background, it is not surprising that North’s statement of over two decades ago is still valid: High-level nuclear waste management “has the deserved reputation as one of the most intractable policy issues facing the United States and other nations using nuclear reactors for electric power generation” (North 1999, 751).

In view of a common understanding to reach a “solution”, it is vital to explore contextual issues and tacit/implicit knowledge – they determine the degree of societal understanding of the eventual disposition system. It is useful to specify what may be “common ground”. Trying to decompose ever-used buzzwords like “consensus” or “compromise” one may outline where and how “common ground” is likely to be achieved. We cannot assume to reach consensus “at heart”, in the stakeholders’ core beliefs. Society must, however, agree on three levels: 1. Problem recognition: The waste exists, the problem must be “solved”, at least set on track to be solved; 2. Main goal consensus: The degree of protection and intervention must be defined; according to the scientific consent, passive safety must prevail; 3. Procedural strategy: The “rules of the game” (to find a suitable site and to implement disposal) have to be clear from the outset.

The present proposal (Flüeler 2023) avoids an undue complexity reduction and a decontextualised “technical fix” or, for that matter, “social fix” (with volunteering communities in the forefront). It is based on a thorough comparison of national waste programmes.

____________________

North, D.W. 1999. A perspective on nuclear waste. Risk Analysis. 19/4. 751-758. https://doi.org/10.1111/j.1539-6924.1999.tb00444.x.

Flüeler, T. 2023. Governance of radioactive waste, special waste and carbon storage. Literacy in dealing with long-term controversial sociotechnical issues. Springer Nature Switzerland, Cham. 145 pp. https://doi.org/10.1007/978-3-031-03902-7.

How to cite: Flüeler, T.: Lessons from national approaches. A long uphill struggle in search of sites for nuclear waste repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6514, https://doi.org/10.5194/egusphere-egu24-6514, 2024.

Rock masses characterized by low permeability (e.g. crystalline rocks) have been considered as natural barriers in the deep geological disposal of high-level radioactive waste. Therefore, groundwater flows within the natural barriers are typically governed by the spatial distribution of fractures within the rock mass. This study focuses on introducing an experimental system designed to evaluate hydro-mechanical properties in the natural barriers. This system allows hydro-mechanical experiments on fracture specimens by employing fluid injection under true triaxial compression conditions. The principal stress state of the underground rock mass can be induced through true triaxial compression conditions, providing the means for its application in the analysis of site-specific properties associated with rock fractures. In particular, the main feature of the experimental system is its capability for bidirectional fluid injection, allowing for hydro-mechanical experiments to be conducted on both individual and intersecting fractures. Detailed specifications have been designed considering the principal stress and groundwater conditions surrounding the KURT (KAERI Underground Research Tunnel), an underground research laboratory in Korea. The preliminary experiments utilizing the constructed experimental system confirmed that true triaxial compression conditions could be implemented while sustaining the loading speed and target stress at a reasonable level. Moreover, it was demonstrated that stable bidirectional fluid injection conditions could be achieved. The examination of applicability was also carried out by employing the experimental system to derive fracture apertures, which represent the hydro-mechanical properties of rock mass. In future investigations, we plan to conduct various hydro-mechanical experiments, employing fracture specimens sampled from the KURT site. This effort is expected to contribute to developing a Korean hydro-mechanical coupled model by evaluating the fracture properties in the KURT site.

Keywords: experimental system, bidirectional fluid injection, true triaxial compression, hydro-mechanical properties, natural barriers

Acknowledgements: This work was supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and the National Research Foundation of Korea (NRF) grant funded by the Korea government(Ministry of Science and ICT, MSIT) (No.2021M2E1A1085200)

How to cite: Lee, Y.-K., Choi, C.-S., and Park, K.-W.: An experimental system capable of bidirectional fluid injection under true triaxial compression conditions for the evaluation of hydro-mechanical properties of natural barriers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6908, https://doi.org/10.5194/egusphere-egu24-6908, 2024.

EGU24-7072 | Posters on site | ERE3.3 | Highlight

HLW site characterization parameters extracted from geophysical well logging data acquired in deep boreholes in Korea 

Seong Kon Lee, Jihun Choi, In Hwa Park, Myung Sun Kim, Kichang Yang, and Dae-Sung Cheon

To select a suitable site for high-level radioactive waste (HLW) disposal, it is very critical to establish site assessment factors that fit the geological conditions of each country, and suitability of a site as a natural barrier of the disposal system should be evaluated and candidate sites should be narrowed down step by step based on these criteria. Site assessment factors can be largely classified into geological, rock mechanical, hydrogeological, and geochemical properties of the deep geo-environment. In Rep. of Korea, 17 items with 98 assessment factors for site assessment factors are suggested. During the period from 2020 to 2024, eight boreholes were excavated to depths of 750 meters in order to increase understanding of the deep geological environment of Korea. The locations for deep boreholes were selected in the area of Korea's four representative major bedrock types and tectonic structures. Drilling cores were recovered from all boreholes to analyze bedrock geology, and rock mechanical properties, and hydrogeological and hyrdo-geochemical pumping and injection tests were carried out to verify general features of site assessment factors of representative bed rocks found in Korea. Geophysical logging methods are a powerful tool in that one can obtain deep geo-envrionmental properties in a dense manner along the borehole walls and obtaining various site mechanical properties by correlating geophysical well logs with laboratory test results. Geophysical logs generally need recompilation and conversion to acquire suitable site assessment factors, such as dynamic elastic properties of the bedrocks, hydraulic parameters of bedrocks. In this paper, we present systematic method and relevant procedures using geophysical logging data to obtain deep geological environment assessment factors essential for the site selection and characterization for HLW disposal sites. The geophysical logging data are basically carried out through 3-Arm caliper logging; temperature, EC(electrical conductivity) of borehole water, and natural gamma logging; gamma-gamma density logging with dual spacings together with borehole diameter logs; normal resistivity logging together with SP(spontaneous potential), single point resistance, spectral gamma logging (K, U, Th), acoustic televiewer(ATV), and sonic logging with three spacing between a source and 3 receivers. The fracture information are analyzed from ATV amplitude and traveltime to be used to determine data sampling information for hydraulic tests and hydrogeochemical experiments, and p- and s-wave velocities obtained from sonic logging were used to obtain rock mechanical properties for site assessment. The characteristics of the fracture zone shows general trends which are of horizontal in mud stone boreholes and of high-angle dip in crystalline rocks, and shows a clear contrast in hydraulic experiments and hydrogeochemical experiments. All of the above results are merged into the database, D-GIVES(Deep-GeoInformation VErification System) for providing deep geo-environment information on site assessment evaluation, and this is also expected to be used as parameters which are necessary in predicting deep geological environment for long-term safety evaluation.

How to cite: Lee, S. K., Choi, J., Park, I. H., Kim, M. S., Yang, K., and Cheon, D.-S.: HLW site characterization parameters extracted from geophysical well logging data acquired in deep boreholes in Korea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7072, https://doi.org/10.5194/egusphere-egu24-7072, 2024.

EGU24-7469 | ECS | Orals | ERE3.3

Modeling in-situ desiccation cracks in a ventilated niche using homogeneously and randomly distributed material parameters 

Tuanny Cajuhi, Gesa Ziefle, Jobst Maßmann, Thomas Nagel, and Keita Yoshioka

Assessing barrier integrity under varying environmental conditions is crucial in the context of radioactive waste disposal. This study, originally  conducted at the Mont Terri Rock Laboratory in Switzerland within the Cyclic Deformation (CD-A) experiment, gains new understanding in this context. The laboratory, located within an Opalinus Clay formation, has been also instrumented to observe the triggers of desiccation cracking in open and closed excavations. Seasonal changes play an important role especially during winter where the relative air humidity reduces and drives desiccation cracking. To model this dynamic, we employed a hydro-mechanical model incorporating macroscopic poromechanics, the Richards equation for partial saturation and the phase-field modeling approach for cracking. Key to our study was the evaluation of unsaturated hydro-mechanical responses using field-acquired parameters such as the measured crack apertures, supplemented by existing literature. We established a good correlation between the observed and calculated crack formation by using the measured seasonal changes in relative air humidity as boundary condition as well as using  homogeneously and randomly distributed material parameters [1]. Furthermore, our study delves into the implications of enhanced permeability due to cracking on barrier integrity. Our findings offer insights into the dynamics of crack development and their implications, thereby making an  incremental contribution to the broader goal of ensuring safe and effective management of radioactive waste disposal.

[1] T. Cajuhi, G. Ziefle, J. Maßmann, T. Nagel and K. Yoshioka, Modeling desiccation cracks in Opalinus Clay at field scale with the phase-field approach. InterPore Journal (in press).

How to cite: Cajuhi, T., Ziefle, G., Maßmann, J., Nagel, T., and Yoshioka, K.: Modeling in-situ desiccation cracks in a ventilated niche using homogeneously and randomly distributed material parameters, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7469, https://doi.org/10.5194/egusphere-egu24-7469, 2024.

EGU24-8817 | ECS | Orals | ERE3.3

Ab initio modelling of magnetite surfaces for radionuclide retention 

Anita S. Katheras, Konstantinos Karalis, Matthias Krack, Andreas C. Scheinost, and Sergey V. Churakov

In many European countries (e.g., France, Switzerland), thick steel casks are foreseen for the containment of high-level radioactive waste in deep geological repositories. In contact with pore-water, steel corrodes forming mixed iron oxides, mainly magnetite (Fe3O4). After tens of thousands of years, the casks may breach allowing for leaching of the radionuclides (e.g., Tc and Pu) into pore-water. The radionuclides can be retarded by corrosion products either by adsorption or via structural incorporation [1,2]. The molecular scale mechanisms of these phenomena are investigated by ab initio simulations and X-ray absorption spectroscopy (XAS).

The dominant low-index surfaces of magnetite particles and their termination at the relevant conditions were identified based on Kohn-Sham density functional theory (DFT), using the open-source CP2K code [3]. The DFT+U method was employed for the strongly correlated 3d and 5f electrons of Fe and Pu, respectively. After benchmarking the model setup, the surface energies of the (111) facet with different surface terminations and water coverage were analyzed as a function of redox conditions and pH. The Eh and pH predominance diagram could be predicted for the most stable surfaces under real repository conditions [4]. Further, we confirmed these findings for nanocrystals with approximately 2 nm size. Subsequently, ab initio molecular dynamics (MD) were applied to simulate sorption structures of radionuclides on the expected magnetite (111) surfaces based on experimental findings [2,5].

[1] R. Kirsch et al. Oxidation State and Local Structure of Plutonium Reacted with Magnetite, Mackinawite, and Chukanovite. Environmental Science & Technology, 2011, 45(17), 7267.

[2] E. Yalçintaş et al. Systematic XAS study on the reduction and uptake of Tc by magnetite and mackinawite. Dalton Transactions, 2016, 45(44), 17874.

[3] T. D. Kühne et al. CP2K: An Electronic Structure and Molecular Dynamics Software Package - Quickstep: Efficient and Accurate Electronic Structure Calculations. The Journal of Chemical Physics, 2020, 152(19), 194103.

[4] A.S. Katheras et al. Stability and Speciation of Hydrated Magnetite {111} Surfaces from Ab Initio Simulations with Relevance for Geochemical Redox Processes. Environmental Science & Technology, 2024, 58(1), 935.

[5] T. Dumas et al. Plutonium Retention Mechanisms by Magnetite under Anoxic Conditions: Entrapment versus Sorption. ACS Earth & Space Chemistry, 2019, 3(10), 2197.

How to cite: Katheras, A. S., Karalis, K., Krack, M., Scheinost, A. C., and Churakov, S. V.: Ab initio modelling of magnetite surfaces for radionuclide retention, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8817, https://doi.org/10.5194/egusphere-egu24-8817, 2024.

During the site selection process in Germany, regulated by the Site Selection Act (StandAG), the implementer has to identify adequate siting regions and perform long-term safety analysis for these regions. The Federal Office for the Safety of Nuclear Waste Management (BASE) as responsible federal authority has to review the implementer’s long-term safety analysis. To perform this duty at the required depth, it will be necessary to recalculate important aspects of the analysis by means of numerical computer programs. In addition, this will allow to assess the underlying uncertainties of the implementer’s long-term safety analysis.

Numerical modelling requires a high degree of quality assurance. Therefore, it is important that the same problem is modelled with different computer programs and – if possible – by different teams of modelers. This strategy is known as the diverse modelling approach and forms the basis of regulatory modelling. It can also be implemented within organizations if more than one code is used to tackle the same task.

The diverse modelling approach has been carried out amongst others by the authors over the past two decades by means of the computer programs, TOUGH2-GRS and MARNIE(2). Both (co-)developed programs are thermo-hydraulic codes that compute transport phenomena in porous media and in the case of MARNIE(2) can be coupled to geochemical codes, see [1] and [2] for further details. A recent example for the diverse modelling approach was the use of TOUGH2-GRS and MARNIE for the development of indicators for the safe confinement of radionuclides in a deep geological repository [3].

At the BASE it is planned to further develop and use the open source program PFLOTRAN in the future for the review of long-term safety analysis. PFLOTRAN [4] is an open source, multi-phase flow and reactive transport simulator designed to leverage massively-parallel high-performance computing to simulate subsurface earth system processes. Amongst other fields of applications, PFLOTRAN has been used to simulate uranium transport at the Hanford 300 Area and is also undergoing qualification for use in performance assessments at the Waste Isolation Pilot Plant (WIPP) [4].

This contribution presents specific repository processes that are part of TOUGH2-GRS and MARNIE but have not yet been completely ported to PFLOTRAN. As an example, we show results from the verification process for anisotropic tortuosities for the diffusive transport of tracers. Another example is the implementation of an effective model for the compaction of salt in the TH part of PFLOTRAN.  These works and the application of PFLOTRAN will strengthen the capabilities of BASE in the independent review process of implementer’s long-term safety analysis within the Site Selection process.

Literature

[1] M. Navarro: User Manual, TOUGH2-GRS Version 2, TOUGH2-MP-GRS Version 0, GRS-505: Köln, 2018.

[2] M. Navarro, J. Eckel et al.: Weiterentwicklung und Qualitätssicherung von Modellierungswerkzeugen zur Durchführung und Bewertung von Sicherheitsanalysen im Standortauswahlverfahren, GRS-622: Köln, 2021.

[3] M. Navarro,  J. Eckel et al.: Indikatoren zur Bewertung des Einschlusses und der Isolation mit exemplarischer Anwendung auf ein generisches Endlagersystem mit dem Wirtsgestein Tongestein, GRS-A-3985: Köln, 2019.

[4] M. Nole et al.: GDSA PFLOTRAN Development (FY2021). United States: N. p., 2021. 

How to cite: Eckel, J. and Navarro, M.: Further development and verification of computer programs for the review of long-term safety analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9291, https://doi.org/10.5194/egusphere-egu24-9291, 2024.

EGU24-9854 | Orals | ERE3.3

Advances in the numerical modeling strategy (concept) of a generic nuclear waste repository in crystalline rock 

Carlos Guevara Morel, Jan Thiedau, and Jobst Maßmann

Safe deep geological disposal of heat-generating nuclear waste requires an accurate assessment of barrier integrity. Therefore, the evaluation of the coupled mechanical, hydraulic, thermal and chemical processes, occurring in the host rock due to the nuclear waste storage, excavation among others is needed. For this purpose, numerical modeling is an essential and powerful tool. This contribution focuses on a generic repository system that relies on a Containment Providing Rock Zone (CRZ) in a crystalline rock, which acts as the principal containment barrier according to German law. Using the open-source finite element code OpenGeoSys version 6, a closer look at the CRZ regarding the influence of fractures on the local hydraulics and potentially available rock zone volume for repository emplacement is shown.

Since fractures and other type of discontinuities usually characterize crystalline rock, they are expected to influence the hydraulic behavior of the system. Hence, their representation in numerical models becomes non-trivial. Here a comparison between different numerical fracture representations and their impact on the hydraulic regime surrounding the CRZ, is presented.

Due to the presence of fractures, it cannot be assumed that a sufficiently large area in which to emplace the waste will be found. As a consequence, multiple smaller CRZs [1], each providing undisturbed rock, have to be defined. Typically, it is only possible to characterize fracture networks statistically, which leads to the use of stochastically generated discrete fracture networks. Using a geometrical characterization of the potentially undisturbed CRZs based on a stochastically generated discrete fracture network, a methodology is proposed to evaluate the feasibility of the multiple CRZs concept.

References

[1] Thiedau, J., et al.: CHRISTA-II - Analysen zur Integrität von geologischen Barrieren von Endlagersystemen im Kristallin. Ergebnisbericht, Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, 2021

How to cite: Guevara Morel, C., Thiedau, J., and Maßmann, J.: Advances in the numerical modeling strategy (concept) of a generic nuclear waste repository in crystalline rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9854, https://doi.org/10.5194/egusphere-egu24-9854, 2024.

EGU24-11241 | ECS | Posters on site | ERE3.3

Time-dependent deformation behavior of Opalinus Clay: A triaxial multi-step creep study under fully drained conditions 

Lina Gotzen, Lisa Winhausen, Mohammadreza Jalali, Kavan Khaledi, and Florian Amann

Ensuring the long-term integrity of deep geological repositories for nuclear waste, i.e., safety and sustainability, remains a critical concern for disposal solutions. Reliable predictions on long-term rock mass behavior require a precise characterization and understanding of time-dependent phenomena such as creep and consolidation. While consolidation involves changes in effective stress, creep is characterized by continuous deformation even under minimal to zero effective stress changes. Parameters which describe the drained creep behavior under fully-saturated rock mass conditions and the long-term strength boundaries (i.e., creep failure) of low-permeable clay shales are limited mainly due to the significant amount of time required for laboratory tests. Creep mechanisms may lead to tunnel convergences and delayed failure, but may also favor self-sealing, even under stress conditions below the short-term peak strength. Consequently, a comprehensive understanding of creep mechanisms is necessary for long-term safety analyses and associated precautionary measures.

In this context, we performed hydro-mechanically coupled triaxial creep experiments using samples of the shaly Opalinus Clay obtained from the Mont Terri Underground Research Laboratory in Switzerland. These tests were conducted on fully saturated and consolidated specimens with bedding orientations parallel and perpendicular to the axial loading direction. We applied step-wise, strain-controlled increases in differential stress under drained conditions, succeeded by creep stages at constant effective stresses. Two different multi-stage stress paths were used. The procedure allows observing deformations related to creep mechanisms for different sample geometries and quantifying the influence of the stress path on the creep behavior.

The study findings reveal the occurrence of both primary and secondary creep even at low differential stresses, along with a distinct anisotropic creep behavior related to the bedding orientation. Increased differential stresses generally result in accelerated secondary creep rates, ultimately leading to creep failure below the short-term strength. The strain-rate data allow a subdivision into a stress-insensitive and a stress-sensitive creep behavior depending on the stress conditions, indicating a difference in the dominating creep mechanisms. Our study also shows that the long-term strength and the creep rates depend on the multi-step stress paths. For smaller incremental increases in differential stress, we find a decreased long-term strength and higher creep rates for the same differential stress.

Our results provide insights into the creep behavior of clay shales and yield crucial parameters for incorporating drained creep as a distinct, time-dependent phenomenon into a constitutive model for Opalinus Clay.

How to cite: Gotzen, L., Winhausen, L., Jalali, M., Khaledi, K., and Amann, F.: Time-dependent deformation behavior of Opalinus Clay: A triaxial multi-step creep study under fully drained conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11241, https://doi.org/10.5194/egusphere-egu24-11241, 2024.

The ThermoBase project aims to investigate the thermal field in sedimentary areas in Germany. It was initiated by the Federal Company for Radioactive Waste Disposal (BGE) and motivated by design calculations and safety analyses that are to be carried out as part of the site selection process for a high-level radioactive waste repository. This research project is carried out jointly by the GFZ German Research Centre for Geosciences and the Federal Institute for Geosciences and Natural Resources (BGR). This contribution focuses on stochastic computations from the BGR on the influence of parameters on the transient temperature field in the underground.
Based on research previously completed by the BGR [1, 2], comparative numerical analyses of the temperature distribution for typical geological situations in Germany are conducted. The focus is on the configuration of thermal material parameters, boundary conditions, and the uncertainty in these parameters. Another objective is to investigate the temperature development and penetration depth of permafrost during a possible future glaciation. Statistical methods, such as the Monte Carlo method and stochastic collocation, will be used to make quantitative statements on the impact of changes in these parameters. Methods for the quantification of uncertainties in geological formations related to heat-generating waste repositories [3, 4], which have recently been developed at the BGR and in the joint project MeQur/URS [5], are used here.

Different generic models are intended to be used for this purpose: (1) a 1D-model in which wide parameter variations will be considered, covering a broad range of different rock types, (2) a 2D-model, representing a case study of a repository system in the Lower Cretaceous claystone in northern Germany [1], and (3) a case study of a salt dome in northern Germany, represented by a 2d rotational symmetric model. The salt dome model includes a rock salt sequence within the Zechstein salt layer where the repository is located.

The first results of this work will be presented. Different studies will be shown for the one-dimensional model (1) quantifying the impact of the modeled uncertainties, including global sensitivity analyses. For the two-dimensional model (2), the effect on the temperature distribution of a stochastic state space, defined by uncertain parameters selected based on results from [3], will be demonstrated and first investigations of the 2D salt dome model (3) will be discussed.

References
[1] Maßmann, J. & Ziefle, G. (2017): Integritätsnachweis geologische Barriere. (In: Jobmann, M. et al.: Systemanalyse für die Endlagerstandortmodelle - ANSICHT). Ber.-Nr.: TEC-29-2016-TB; Peine, Hannover, Braunschweig (DBE TECHNOLOGY, BGR, GRS).
[2] Mönig, et al. (2020): RESUS: Synthesebericht. GRS; 567; Köln.
[3] Maßmann, J. et al. (2022): ANSICHT-II – Methode und Berechnungen zur Integritätsanalyse der geologischen Barriere für ein generisches Endlagersystem im Tongestein. BGR, Hannover. DOI:10.25928/n8ac-y452.
[4] Bittens, M., & Gates, R. L. (2023): DistributedSparseGrids. jl: A Julia library implementing an Adaptive Sparse Grid collocation method. Journal of Open Source Software, 8(83), 5003.
[5] Nagel, T, et. al. (2023): MeQur - Uncertainties in THM-coupled integrity calculations, Project web page; URL: https://urs.ifgt.tu-freiberg.de/en/topics/mequr, [Accessed 09-01-2024]

How to cite: Maßmann, J., Bittens, M., and Noack, V.: Statistical analyses on the relevance of thermal data for the safety-related assessment of repository systems - first results from the project ThermoBase, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12494, https://doi.org/10.5194/egusphere-egu24-12494, 2024.

EGU24-13377 | Orals | ERE3.3 | Highlight

International Concepts for the Assessment of Deep Geological Disposal of Radioactive Waste 

Boris Faybishenko, Jens Birkholzer, LianGe Zheng, David Sassani, and Emily Stein

More than 50 countries worldwide are currently exploring options for radioactive waste (RW) disposal, considering the link between geoscience fundamentals and the safety of RW disposal sites. The presentation will focus on the lessons learned from representative RW disposal projects worldwide (such as those conducted in Sweden, Finland, France, Spain, Switzerland, Japan, and the USA), summarizing the existing deep geological repository (DGR) concepts, including potential DGR site selection and characterization, as well as long-time modeling predictions. A comparative assessment of models of coupled thermo-hydro-mechanical-chemical (THMC) processes has been performed within the scope of the international project DECOVALEX, which has helped advance the understanding of THMC processes in geological systems. The experimental and modeling studies of the DGR concepts are ultimately linked to assessing the safety of RW disposal. The presentation will provide critical references and case studies related to the representative national disposal programs, which would interest geoscientists, engineers, and decision-makers working on national RW disposal programs. We will summarize and compare challenging geological problems and experiences in siting nuclear waste repositories in different host rocks, such as hard rock (crystalline and sediments), clayey, and salt formations. The availability of rock in a country limits the choice of rock type for the DGR. The interplay of geological conditions with technical feasibility, an engineering design for different rock types and operational and post-closure safety is critical in technical evaluating potential sites. We will also present summaries of the progress in international cooperation studies and testing of the design of buffer and backfill materials, the development of the concept of RW disposal in deep boreholes, the R&D research in Underground Research Laboratories (URL), and multi-national RW repository initiatives. 

Acknowledgments: LBNL work was supported under Contract Number DE-AC02-05CH11231 with the US DOE. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

 

How to cite: Faybishenko, B., Birkholzer, J., Zheng, L., Sassani, D., and Stein, E.: International Concepts for the Assessment of Deep Geological Disposal of Radioactive Waste, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13377, https://doi.org/10.5194/egusphere-egu24-13377, 2024.

EGU24-14424 * | Orals | ERE3.3 | Highlight

State of the art in science and technology for unique and lengthy administrative procedures - How does it work? 

Susanne Schneider, Harriet Kause-Berg, and Florian Baasch

In Germany disposal of low- and intermediate level radioactive waste is intended and took place in deep geological repositories. Two repositories in very different stages of their life cycle exist in Germany, both are disused mines. For the ERAM repository (Endlager für radioaktive Abfälle Morsleben) decommissioning and closure is expected to start in 2029. Radioactive waste was last stored in 1998. For the KONRAD repository (Schachtanlage Konrad) commissioning and storage of radioactive waste is anticipated in 2030. The respective permits regulate, how the final repository is designed, what protective measures must be taken, which waste may be stored in what form and how the final repository is to be closed. ERAM and KONRAD were approved in 1986 and 2002, respectively; both approval processes took place in previous decades. Since then, both repositories have been continuously adapted to the current state of the art in science and technology. But what is the “current state of the art in science and technology”, who defines it and what does it mean for the approval of deep geological repositories? In this contribution we will show examples of how the state of the art in science and technology finds its way into supervision and licensing activities and which actors are involved. Finally, we discuss how we could optimize these processes and what we might learn for the permission of a repository for high radioactive waste.

How to cite: Schneider, S., Kause-Berg, H., and Baasch, F.: State of the art in science and technology for unique and lengthy administrative procedures - How does it work?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14424, https://doi.org/10.5194/egusphere-egu24-14424, 2024.

The identification of appropriate locations for secure nuclear waste disposal, a crucial aspect of Germany's nuclear phase-out strategy, remains a significant scientific, technical, and political challenge worldwide. The selection and safety assessment of sites demand extensive employment of numerical methods. The OpenWorkFlow project, initiated by Bundesgesellschaft für Endlagerung (BGE), is developing a new, open synthesis platform to virtualise repository systems. The simulation platform will evaluate far-field and near-field processes, aiding the site selection process first and geotechnical design of repository systems later on. Automated simulation and analysis pipelines developed in this project ensure the verifiability and reproducibility of all simulation results and the modularity of workflows brings flexibility, continuity and maintainability.

This project defines high scientific benchmarks and standards for numerical models and software development for the repository search in Germany. OpenWorkFlow as an efficient and holistic platform for numerical modelling will contribute to a science-based, transparent, and precise execution of the necessary safety assessments. This project includes all theoretical, numerical and computational methods and tools, including a virtual reality framework. OpenWorkFlow will be continuously developed by the core project team, but will also actively involve the community through its open concept (e.g. through the interactive benchmarking platform). This will create a win-win situation in the long run.

This talk is based on the paper Christoph Lehmann, Lars Bilke, Jörg Buchwald, Nico Graebling, Norbert Grunwald, Julian Heinze, Tobias Meisel, Renchao Lu, Dmitri Naumov, Karsten Rink, Ozan Özgür Sen, Philipp Selzer, Haibing Shao, Wenqing Wang, Florian Zill, Thomas Nagel, and Olaf Kolditz. Openworkflow - development of an open-source synthesis-platform for safety investigations in the site selection process. Grundwasser, 2024. in print.

How to cite: Lehmann, C., Nagel, T., and Kolditz, O.: OpenWorkFlow - Development of an open-source synthesis-platform for safety investigations in the site selection process, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14633, https://doi.org/10.5194/egusphere-egu24-14633, 2024.

The site selection procedure for the deep geological storage of high-level radioactive waste in Germany started with a “white map”, i.e., with the entire federal territory, and considers all of three potential host rocks: rock salt, clay rock, and crystalline rock. In a first phase of the site selection procedure, Bundesgesellschaft für Endlagerung (BGE, i.e., Federal Company for Radioactive Waste Disposal) is determining regions for surface exploration based on the previously identified sub-areas that meet the minimum requirements defined by law. As the sub-areas cover approximately 54% of Germany's area, the site selection methodology must not only include safety assessments but must also lead to a significant safety-oriented reduction of the considered area towards the best-suited regions for surface exploration.

Several challenges arise for the determination of the regions for surface exploration. As legal regulations provide only a framework for the procedure but largely lack explicit assessment criteria, a methodology must be developed that is in accordance with the law and that also supplies the tools to evaluate and narrow down the remaining areas. In addition, the safety-oriented evaluation and area reduction must be done legally on the basis of available data only, which is sparsely available and mostly not specific to the needs for site evaluation. Only in the next phase of the site selection procedure can BGE collect data during surface exploration for a more detailed site characterization. Finally, the developed methodology, as well as decisions based on its application to the sub-areas, must be transparent and comprehensible to permit discussions with stakeholders and the public. Data availability and associated uncertainties provide a specific challenge in ensuring this transparency during the decision-making.

To address the challenges, BGE is developing a methodology that concretizes the legal requirements and translates them into a plausible evaluation system with well-defined criteria. These host-rock-specific evaluation criteria derived from the legal requirements allow a reproducible, systematic and thus transparent evaluation of safety-relevant attributes. The criteria are applied successively in a series of work steps, such that the level of detail and the strictness of requirements increase throughout the selection process. Thus, less-suitable areas are identified early on in the procedure with limited effort, while areas that are more promising are analyzed in greater detail – providing also the basis for a comparison between areas – and must pass successively higher requirements. The level of knowledge, which increases throughout the selection process, is taken into account when deciding on the evaluation criteria for a specific work step, such that heterogeneous data availability influences the decision-making as little as possible. However, poor data availability and verifiability of geologic realities are fundamental problems for the decision-making process that need to be addressed and discussed openly.

How to cite: Rempe, M., Fink, R., Panitz, F., and Romer, R.: Selection of regions for surface exploration in the search for a repository for high-level radioactive waste in Germany: Decision-making in a safety-oriented site selection procedure with sparsely available data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14693, https://doi.org/10.5194/egusphere-egu24-14693, 2024.

EGU24-14934 | Orals | ERE3.3 | Highlight

Hypothetical measures on high-level radioactive waste from the perspective of extended interim storage and final disposal 

Guido Bracke, Lena Maerten, and Christoph Borkel

The site selection for a repository for high-level radioactive waste (HLW) will take longer than the currently authorised period of 40 years for interim storage sites in Germany. Extension of this period could necessitate additional handling or measures, such as treatments of HLW. This might have an impact on radionuclide mobility in the final repository. Therefore, BASE initiated a research project that studied the behaviour of HLW in interim storage was studied for causes of degradation, effects and consequences and possible treatments, performed by GRS gGmbH. There are currently no indications for mandatory measures during the authorized period and beyond, but some hypothetical treatments were identified. These treatments were evaluated with regard to their impact on interim storage, radiation exposure for personal, manageability and radionuclide mobility in repositories. Measures include, for example, heating and earlier removal from interim storage for conditioning. Even though technical feasibility was not part of the study, it seems clear that with any of the identified measures, higher radiation doses would have to be expected for the personnel. The impact of these measures on radionuclide mobility in the repository is assessed to be low. However, a more quantitative assessment of the impact of hypothetical treatments appears only feasible when a repository concept including waste acceptance criteria is fixed, which is not the case at the time of the study.

How to cite: Bracke, G., Maerten, L., and Borkel, C.: Hypothetical measures on high-level radioactive waste from the perspective of extended interim storage and final disposal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14934, https://doi.org/10.5194/egusphere-egu24-14934, 2024.

EGU24-15328 | Orals | ERE3.3

Finite-Element Analysis of Phase Transitions in Gas Migration within Clay Rock 

Norbert Grunwald, Thomas Nagel, Michael Pitz, and Olaf Kolditz

This study explores the numerical simulation of gas transport in low-permeable rocks, specifically focusing on clay rock. Utilizing the finite-element method, we examine the transition from single-phase to two-phase flow conditions. Our approach diverges from traditional methods by avoiding persistent primary variables or variable switching. We validate our methodology through two benchmark tests: the first simulates gas injection relevant to radioactive waste disposal, while the second models a core drilling experiment that induces mechanical unloading.

Our findings are significant for understanding gas behavior in geological formations, particularly in the context of nuclear waste disposal and CO2 storage. We offer a novel perspective on managing phase transitions in non-isothermal environments, bolstered by an extensive analysis of secondary variables. The outcomes of this research contribute to the improved modeling of large-scale repository systems, highlighting the intricacies and complexities involved in gas transport within clay rock.

This paper not only provides insights into the physical processes underpinning gas movement in these environments but also proposes a scalable and adaptable framework for future research in similar geological contexts.

How to cite: Grunwald, N., Nagel, T., Pitz, M., and Kolditz, O.: Finite-Element Analysis of Phase Transitions in Gas Migration within Clay Rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15328, https://doi.org/10.5194/egusphere-egu24-15328, 2024.

EGU24-15464 | Posters on site | ERE3.3

Enhancements of geomechanical models for potential siting areas in Switzerland 

Karsten Reiter, Moritz Ziegler, Oliver Heidbach, Jean Desroches, Erling Fjær, and Silvio Giger

After the upper earth's crust was mainly explored in the last century for the extraction of water, minerals and energy resources, the focus of exploration is increasingly shifting to the temporary storage of energy, the extraction of thermal energy and the disposal of CO2 or radioactive waste. The geomechanical stability of the host rock is particularly relevant for the barrier integrity of a geological repository. The stresses acting on the lithologies and the waste-induced pore pressure evolution determine whether a potential failure can occur. Various methods are used to estimate individual components of the stress tensor on a meter scale. Since the local stress state may be strongly influenced by tectonic structures and spatially variable rock properties, it is necessary to apply 3-D geomechanical models, to predict the spatial distribution of the stress state beyond the in-situ data.

Geomechanical-numerical models require detailed information about the structural composition such as stratigraphic boundaries or faults, and the material properties of the subsurface lithologies. Technically the task is to estimate the equilibrium of forces between gravity and the elastic response due to lateral displacement boundary conditions that result in a best-fit with respect to pointwise stress magnitude data. With the increase in available data, the calibration process becomes more complex, but also provides a framework for testing the validity of the data and the models.

Motivated by the Sectoral Plan Deep Geological Repositories, a comprehensive exploration program was done in three sites in Northern Switzerland between 2016 and 2021, involving 3-D seismic surveys and drilling of nine boreholes. This enabled to refine 3-D geomechanical-numerical models for the potential repository sites. These models differ significantly not only due to the improved geometrical data, but the large number of stress magnitude data and the increased numerical resolution. The presentation is intended to provide an overview of the modelling process, the calibration procedure, the new features of the models and the key results.

How to cite: Reiter, K., Ziegler, M., Heidbach, O., Desroches, J., Fjær, E., and Giger, S.: Enhancements of geomechanical models for potential siting areas in Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15464, https://doi.org/10.5194/egusphere-egu24-15464, 2024.

EGU24-15607 | Posters on site | ERE3.3

CHENILLE: the fault-heating experiment in the URL Tournemire (France) 

Rüdiger Giese, Audrey Bonnelye, Pierre Dick, Carolin Boese, Stefan Lueth, Ben Norden, Katrin Plenkers, Roman Esefelder, Christian Cunow, Liang Pei, and Sven Fuchs

The understanding of the coupled thermo-hydro-mechanical behavior of fault zones in naturally fractured rocks is essential both for fundamental and applied sciences and in particular for the safety assessment of radioactive waste disposal facilities. An international research program called CHENILLE was built to address key questions related to the impact of high temperatures (up to 120°C) on shear zones as well as fault reactivation processes in shale formations. Here, we report on an ongoing thermally controlled in-situ fluid injection experiment on a strike-slip fault zone outcropping at IRSN’s Tournemire Underground Research Laboratory (URL). This includes a series of laboratory experiments to understand the mechanical, hydraulic, structural and thermal evolution occurring within the fault zones during the thermal and hydraulic loading. Reported preliminary results comprise acoustic emission activity and active seismic monitoring results, the thermal diffusion and the temperature evolution measured in-situ with DTS in and around the fault and the corresponding numerical thermal simulation of the experimental setup.

How to cite: Giese, R., Bonnelye, A., Dick, P., Boese, C., Lueth, S., Norden, B., Plenkers, K., Esefelder, R., Cunow, C., Pei, L., and Fuchs, S.: CHENILLE: the fault-heating experiment in the URL Tournemire (France), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15607, https://doi.org/10.5194/egusphere-egu24-15607, 2024.

EGU24-16099 | Orals | ERE3.3 | Highlight

Modelling of glacial melt water erosion of the overburden of a HLW over 1 million years 

Matthias Brandt, Anton Carl-Dworschak, Andreas Jockel, and Rene Kahnt

The site selection procedure in Germany is searching for a site with the best possible safety for a repository for high-level waste (HLW). The integrity of the overburden is crucial in the assessment of the best possible safety (StandAG §23 (5), para.3). Beyond the safe inclusion in the selected host rock for a HLW repository, a sufficient stability of the overlaying overburden horizons must be ensured. Erosion by glaciation induced processes are but one of the potential threats to the stability of these overburden horizons. The research project presented here is funded by BASE under the grant number FKZ 4721F10401.
Within the research project “Evaluation of methods and models to predict the protective function of the overburden in Germany over the period of 1 Ma” (MeMoDeck) a framework to assess the risks introduced by glacial erosion that are to be expected within 1 million years was developed. As an indication of this, the erosion processes, prevailing during the Pleistocene, have been analysed with respect to the extent of the erosion depth introduced by them. The largest depths are attained to incisions by subglacial meltwater transport in the form of tunnel valleys. 
The authors employed a combined modelling approach, which includes a three-dimensional deterministic numerical modelling of the tunnel valley genesis with FLAC3D and a multivariate probabilistic modelling with GoldSim to account for the remarkable uncertainties over 1 Ma. The uncertainties result from the lack of data with respect to hydraulic conditions during the melting of the ice sheet and the variability of the erosion resistance of the geological horizons of the overburden, which overlies the respective host rock. 
The authors determine the depth of a prospective tunnel valley by a simulation at well-constrained geological and melt water conditions by the deterministic FLAC3D model.
The results from the deterministic modelling with Flac3D are the basis of the simulation within the probabilistic model with GoldSim, which relaxes the modelling constraints towards melt water and geological properties using statistical distribution functions for these quantities.
The results of the modelling will be presented and the most influential parameters towards the final depths of the overburden incisions will be discussed.

How to cite: Brandt, M., Carl-Dworschak, A., Jockel, A., and Kahnt, R.: Modelling of glacial melt water erosion of the overburden of a HLW over 1 million years, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16099, https://doi.org/10.5194/egusphere-egu24-16099, 2024.

EGU24-16144 | ECS | Posters on site | ERE3.3

Dynamics of large-scale THM simulations: numerical considerations for the simulation of nuclear waste repositories in rock salt during glacial cycles 

Florian Zill, Tobias Meisel, Christian B. Silbermann, and Thomas Nagel

This study addresses the coupled thermo-hydro-mechanical (THM) modelling of large-scale nuclear waste repositories situated in rock salt. We consider the competing stability requirements arising from different physical processes, such as advection and diffusion in the rock mass surrounding the saline barrier, as well as viscoplastic creep of the latter. Our focus extends to examining potential conflicts between spatial and temporal discretization demands, balancing performance, stability and accuracy. We systematically investigate the applicability of these considerations to a model implemented in OpenGeoSys, aiming to enhance its robustness. 

An essential aspect of evaluating simulation results is analyzing the convergence behavior in the absence of an analytical solution. Several methods exist to extrapolate model results of different discretization to a reference set, such as the Richardson extrapolation. Here, we use such a technique to scrutinize our results, providing a comprehensive assessment of the model's convergence characteristics and the accuracy of the results.

Finally, detailed comparisons across various coupling schemes are conducted for our model, highlighting the impact of implicit process coupling on the model results.

How to cite: Zill, F., Meisel, T., Silbermann, C. B., and Nagel, T.: Dynamics of large-scale THM simulations: numerical considerations for the simulation of nuclear waste repositories in rock salt during glacial cycles, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16144, https://doi.org/10.5194/egusphere-egu24-16144, 2024.

EGU24-16507 | Orals | ERE3.3

Bentonite erosion by expansion in fractures: effect of exposed surface and clay mass 

Mikel Dieguez, Jesús Morejon, Manuel Mingarro, Miguel García-Gutiérrez, Tiziana Missana, Patrik Sellin, and Úrsula Alonso

Compacted bentonite is the primary engineered barrier in a deep geological repository for high-level radioactive waste. The bentonite must exhibit a sufficiently high swelling capacity and low hydraulic conductivity to seal the waste and to hinder radionuclide migration (Sellin & Leupin, 2013). The erosion of the barrier due to the flow of groundwater, which promotes clay swelling and expansion through fractures in the crystalline host rock, would entail a loss of mass in the bentonite, which could compromise the effectiveness of the barrier.

Bentonite erosion is usually experimentally studied at laboratory scale, by analyzing the role of different parameters such as the type of clay, water chemistry or the physical conditions of the fracture in a controlled manner. The extrapolation of laboratory results to a real repository requires compulsory evaluating the role of those aspects more sensitive to scale effects. This study investigated whether the amount of clay emplaced or the clay surface in contact with fractures play a role in erosion process.

For this, an experimental set-up to simulate an artificial fracture was used (Alonso et al., 2019). In this setup, a compacted bentonite sample is placed between two methacrylate plates with a known aperture. All experiments were performed at a dry density of 1.4 g/cm3 with a previously sodium equilibrated clay (NANOCOR®). Fractures are placed in horizontal position and filled with a low saline solution (10-3 M NaCl), to monitor the expansion distances of the clay in the fracture by periodic photographs. The clay is allowed to expand during 30 days and the amount of clay eroded is quantified post-mortem. Two sets of experiments were carried out, the first set evaluated the impact of clay area exposed to hydration in the fracture, fixing the amount of clay mass, with samples of ring geometry. For the second set, the clay exposed surface contacting the fracture was kept constant, but the amount of clay installed was varied with cylindrical compacted samples of variable height.

Results showed that clay expansion can only occur in water conductive fractures, and no expansion was observed in the inner zone of the ring geometry tests, which were not water filled. Additionally, no large differences in the expansion distance were observed in the tests with a larger exposed surface area. For the second set of experiments with cylindrical geometry and the same exposed area, it was observed that the expansion and mass loss did not vary significantly with different clay mass. The indication is that in a genuine repository featuring substantially greater volumes of clay, the impact of this factor on its expansion should not be considerable.

REFERENCES

Alonso, U., Missana, T., García-Gutiérrez, M., Morejón, J., Mingarro, M., & Fernández, A. M. (2019). CIEMAT studies within POSKBAR project Bentonite expansion, sedimentation and erosion in artificial fractures (Technical Report TR-19-08). SKB.

Sellin, P., & Leupin, O. X. (2013). The Use of Clay as an Engineered Barrier in Radioactive-Waste Management – A Review. Clays and Clay Minerals, 61(6), 477–498. https://doi.org/10.1346/CCMN.2013.0610601

How to cite: Dieguez, M., Morejon, J., Mingarro, M., García-Gutiérrez, M., Missana, T., Sellin, P., and Alonso, Ú.: Bentonite erosion by expansion in fractures: effect of exposed surface and clay mass, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16507, https://doi.org/10.5194/egusphere-egu24-16507, 2024.

EGU24-17172 | ECS | Posters on site | ERE3.3

Spectra of stress: Variability in lithologies represented in geomechanical models 

Moritz Ziegler, Karsten Reiter, Oliver Heidbach, Jean Desroches, Erling Fjaer, and Silvio Giger

Knowledge of the current undisturbed stress state is a key issue of subsurface applications. Amongst others, the stability of caverns and boreholes depend on the stress magnitudes. For the prediction of the stress in a rock volume 3D geomechanical-numerical models are used. Technically the task is to estimate the equilibrium of forces between gravity and the elastic response due to lateral displacement boundary conditions that result in a best-fit with respect to pointwise stress magnitude data. For sensitivity studies of the effect of variable boundary conditions, the rock properties (Young’s modulus, Poisson ratio, density) are assigned to the corresponding lithologies that are implemented in the model volume. However, mainly the Young’s modulus has a high variability within each lithological unit.

We demonstrate an approach where obtained information on the rock property distribution is included in a geomechanical model to provide several possible stress states. From these individual cases the range of stress states that are likely to be expected are estimated. This results in a bandwidth for the components of the stress tensor. For each component, a median stress magnitude is provided as well as a 1σ and 2σ range. This allows a more comprehensive estimate of the stress state which, in turn, allows to include uncertainties on stress magnitudes in the design of underground structures due to being more informed. Even though, a safety margin will always have to be included, well known and quantified uncertainties may lead to a reduction of said margin. In turn, this improves economic feasibility. The required safety margins can be adapted to the prevailing stress state for each individual unit if potentially unstable zones are identified well in advance.

We demonstrate the applicability of the approach on the site of a planned deep geological repository. The Swiss National Cooperative for the Disposal of Radioactive Waste (NAGRA) provides an unprecedented amount and quality of both stress magnitude and rock property data records for this site. For each unit a cumulative density function of the rock properties is available which allows a robust assessment of the variability. Eventually, we are able to provide a bandwidth of the expected stress magnitudes throughout the model volume. A comparison with the measured bandwidths of stress magnitude data records along borehole trajectories shows a very good agreement between the modelled bandwidth and the range of obtained stress magnitudes.

How to cite: Ziegler, M., Reiter, K., Heidbach, O., Desroches, J., Fjaer, E., and Giger, S.: Spectra of stress: Variability in lithologies represented in geomechanical models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17172, https://doi.org/10.5194/egusphere-egu24-17172, 2024.

EGU24-20815 | Orals | ERE3.3

Microbiological Analysis of SURAO Low-pH Concrete (LPC) in repository-like conditions 

Veronika Hlavackova, Trung Duc Le, Jakub Riha, Petr Vecernik, Tomas Cernousek, Lucie Hausmannova, Radek Vasicek, and Alena Sevcu

Low-pH concrete (LPC) is used as one of the main construction components of deep geological repositories (DGR) for radioactive waste. The mechanical and chemical stability of this material is crucial for the long term DGR sustainability. However, the presence of microorganisms in the underground environment and backfill matrices could significantly affect its stability and in turn the safety of DGRs. The buffer and backfill matrix (bentonite) and underground water are potential long-term sources of bacteria in DGR. The WP MAGIC as a part of the European joint program EURAD focuses on studying the chemo-mechanical behavior of concrete under varied conditions. The project compares the effect of three different conditions – air, water and bentonite - on aged SURAO LPC samples. The 2-year experiment is disposed in Czech Underground Research Facility (URF) Bukov. Our aim was to investigate microbial activity in LPC discs and describe the capability of present microorganisms to affect the mechanical properties of LPC in time. The microbiological analysis comprised of both cultivation dependent and independent approach. The microbial activity was also confirmed using epifluorescent microscopy and scanning electron microscopy. Our findings reveal unique microorganisms in each of in-situ condition, highlighting their potential effect on mechanical properties of LPC.

How to cite: Hlavackova, V., Le, T. D., Riha, J., Vecernik, P., Cernousek, T., Hausmannova, L., Vasicek, R., and Sevcu, A.: Microbiological Analysis of SURAO Low-pH Concrete (LPC) in repository-like conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20815, https://doi.org/10.5194/egusphere-egu24-20815, 2024.

EGU24-20864 | Posters on site | ERE3.3

Microbial activity in Cementitious Matrices for the Storage of Radioactive Waste from the Decommissioning of Nuclear Power Plants  

Alena Sevcu, Petr Vecernik, Rojina Shrestha, Jakub Riha, Milan Kouril, and Veronika Hlavackova

The most used materials in civil engineering is concrete and steel. Their unique properties made them candidate materials for components of engineered barrier system for high- and intermediate-level radioactive waste (ILW and HLW) deposition including material from decommissioning of nuclear power plants. Activated materials include mainly stainless steel of nuclear reactor structural elements or carbon steel and shielding concrete of the reactor shaft construction materials. This study is focused on standard and alternative cementitious matrices for deposition of such activated materials mainly in terms of its long-term sustainability in the presence of microorganisms.

Four different matrices including cement paste based on Ordinary Portland Cement (OPC), cement paste enriched with bentonite or nano-iron, and finally geopolymer, are exposed to conditions that simulate real repository (anaerobic groundwater). One of the objectives is to describe the growth of microorganisms on/in these matrices as a potential risk for the long-term sustainability of such disposal. After a defined time, changes in microbial activity of the matrices, water leachate and interface between matrix and metal coupons simulating activated waste are monitored using cultivation-dependent and independent approach. Here we will demonstrate results of first samplings after 6, 12 and 24 months of incubation in anaerobic conditions. The results will shed more light on evolution of microbial activity in such extreme conditions in time and bring more information on processing and detection of microbial activity in alkaline materials.

How to cite: Sevcu, A., Vecernik, P., Shrestha, R., Riha, J., Kouril, M., and Hlavackova, V.: Microbial activity in Cementitious Matrices for the Storage of Radioactive Waste from the Decommissioning of Nuclear Power Plants , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20864, https://doi.org/10.5194/egusphere-egu24-20864, 2024.

EGU24-21341 | Posters on site | ERE3.3

Characterisation of thermally affected corrosion products originating on steel-bentonite interface 

Sarka Sachlova, Vlastislav Kašpar, Petr Večerník, and Michaela Matulová

The Czech national concept of the deep geological repository (DGR) is based on the Swedish KBS-3 concept including an engineered barrier system (EBS) situated in the crystalline host rock. The EBS comprises the double-walled waste disposal package (WDP) embedded in compacted bentonite in vertical drill holes. The double-walled WDP comprises the inner carbon steel package and the outer stainless steel package. Regarding the concept, there was a designed laboratory experiment simulating the thermal and irradiation loading of stainless steel coupons embedded in saturated compacted bentonite.

Four experimental setups were conducted using compacted BCV and MX80 bentonites under anoxic conditions differing in initial saturation level (15-20 wt. %), heating temperature (ambient temperature, 90°C and 150°C), and irradiation (0.4 Gy/h). The analysis of steel samples included: visual inspection, scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), Raman spectroscopy, and profilometry. Corrosion rate was calculated from the mass loss. The analysis of bentonite samples included: analysis of chemical (X-ray fluorescence microscopy, XRF) and mineralogical (XRD) composition, cation exchange capacity (CEC), and SEM-EDS analysis.

The steel samples embedded in the BCV bentonite heated up at 150 °C indicate a lower corrosion rate when irradiated compared to unirradiated samples. A combination of 150 °C and irradiation leads to surface corrosion indicating an almost constant corrosion rate for the whole testing period. Unirradiated samples heated up to 150 °C showed the highest corrosion rate after 6 months with decreasing tendency when the loading period was prolonged up to 18 months. The decreasing corrosion rate was observed in both irradiated and unirradiated steel samples heated up at 90 °C correlating with increasing loading period. A minimum corrosion rate was found in steel samples embedded in water-saturated BCV bentonite stored under laboratory temperature without irradiation. The inhibiting effect of irradiation on steel corrosion was observed when the steel samples were embedded in MX80 bentonite heated up at 150 °C. Almost no effect of irradiation was observed when the MX80 bentonite was heated up at 90 °C. 

Hematite and Fe-rich carbonates (chukanovite, siderite) were confirmed to form corrosion layers on the steel surface. The thickness of the corrosion layer varied, ranging from 10 to 45 µm, and was directly correlated with the loading duration. Steel samples that remained unirradiated and were heated up at 90 °C exhibited corrosion layers up to 45 µm in thickness after 12 months of loading. In contrast, irradiation and heating up at 150 °C led to the formation of thinner corrosion layers, typically ranging from 10 to 20 µm. The corrosion layer composed of Fe-Si-O was identified only on the surface of steel heated up to 150 °C. The layer was identified only by SEM-EDS indicating amorphous or poorly crystalline structure. The origin of Fi-Si-rich corrosion products needs to be confirmed by future research.

How to cite: Sachlova, S., Kašpar, V., Večerník, P., and Matulová, M.: Characterisation of thermally affected corrosion products originating on steel-bentonite interface, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21341, https://doi.org/10.5194/egusphere-egu24-21341, 2024.

EGU24-757 | ECS | Posters on site | ERE3.6

Adjusted models for aquifer thermal energy storage (ATES) systems simulations 

Elzbieta Halaj, Bartosz Papiernik, and Leszek Pajak

ATES systems can be coupled with various types of building facilities providing heating, cooling and thermal energy storage. The thermal performance and dynamical simulations of ATES systems should be provided based on local structural and parametric framework.

A static model, which can correctly represent the geological nature of the reservoir, is necessary in order to achieve a reliable evaluation and assessment through numerical simulations.

Recent 3D static geomodels from petroleum exploration built for R&D purposes of Department of Energy Resources AGH University of Krakow were adjusted for further geothermic and energy storage fields (ATES, CO2 sequestration) purposes.

These parametric geomodels are very complex, handling large quantities of input data. A typical static modelling workflow comprises 6 main phases of modelling, starting from database building, through structural modelling, facies modelling, petrophysical modelling, up to volume and reserves calculations and risk assessment.  

One of the examples is a performance simulation of ATES in the Lower Cretaceous reservoir in Central Poland, where a regional Petrel© static parametric model was prepared prior to dynamic simulations in Feflow© software. A methodology of fitting Petrel’s structural and parametrical model to Feflow requirements were prepared.

The basic surfaces constraining the geometrical framework of the dynamic model — in particular top and base on the Lower Cretaceous — were extracted from the regional model. The square part of this model was extracted and subsequently converted into formats applicable in Feflow©. Further assumptions were made for geological and thermal parameters.

In result, the ATES systems can be simulated as a doublet of multilayer wells, which applies a pre-defined extraction or injection nodes along a well screen. The dynamic model was divided in sub-layers of variable thickness. The porosity in the Lower Cretaceous formations was set according to geological static

model. The thermal model of the area was then validated and compared with the geological static model. The performance of ATES simulation was conducted for 30 years according to its specific demand profile.

 

How to cite: Halaj, E., Papiernik, B., and Pajak, L.: Adjusted models for aquifer thermal energy storage (ATES) systems simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-757, https://doi.org/10.5194/egusphere-egu24-757, 2024.

EGU24-1482 | ECS | Posters on site | ERE3.6

Modeling and simulation of combined basin structures for seasonal thermal energy storage 

Christoph Bott and Peter Bayer

Seasonal thermal energy storage (sTES) plays a crucial role in driving forward the global energy transition by tackling the intermittent nature of renewable energy sources. While communities increasingly rely on sustainable yet variable sources such as solar thermal, photovoltaics, and wind power, the importance of efficient energy storage solutions becomes key. These solutions need to contribute to grid stability, diminish reliance on fossil fuels, and optimize energy utilization while supporting resilient and sustainable energy systems. Among the technological variants for sTES, closed-loop alternatives for in-ground, artificial basin systems involve water-gravel thermal energy storage (WGTES) and tank thermal energy storage (TTES). They consist of a filling medium operated via a direct or indirect charging/discharging system and which is enclosed by a membrane consisting of sealing layers, insulation materials, and, if necessary, static structures [1].

Especially for supplying modern, dynamic district energy systems, high requirements apply to sTES in terms of temperature levels as well as volume flow rates. At the same time, high costs for the construction of new systems are an enormous hurdle that hinders global market availability. For this reason, re-using existing basin structures, for example, at locations of transforming commercial and industrial areas, is a new concept that also offers new opportunities for innovations of sTES concepts. Especially at sites with the option of re-using existing infrastructures, not only single but multiple structures may be available. These may, for example, feature subdivided infrastructure compounds yielding an extra challenge for design, construction, and operation. Connecting several separately tuneable sTES units in one system in parallel or as a cascade offers enhanced flexibility. For this purpose, we present a modification of a recently developed model for WGTES, “STORE” [2], that is capable of simulating the behavior of a variety of sTES combinations with different configurations, designs, and operational principles. Based on a realistic case study, and taking several reference units (e.g., energy, storage capacity, power) into consideration, we investigate technical issues, e.g., optimal interconnection, insulation designs, and interference with ambient ground, in contrast to static integrations of a single sTES facility. In particular, we reveal the effects of the combined placement of multi-sTES systems and their thermal interference through internal walls, and with the ambient ground. We present the findings of a parameter study to investigate ideal combinations and sophisticated modes of operation, e.g., by operating a central basin at the highest temperature level whereas outer basins are kept at lower temperatures. Based on this analysis, we infer favorable application windows for combined basin structures and strategies to increase overall efficiency.

References

1. Bott, C., Dressel, I., & Bayer, P. (2019). State-of-technology review of water-based closed seasonal thermal energy storage systems. Renewable and Sustainable Energy Reviews, 113, 109241.

2. Bott, C., Ehrenwirth, M., Trinkl, C., Bayer, P. (2022). Component-based modeling of ground-coupled seasonal thermal energy storages. Applied Thermal Engineering, 118810, doi: 10.1016/j.applthermaleng.2022.118810.

How to cite: Bott, C. and Bayer, P.: Modeling and simulation of combined basin structures for seasonal thermal energy storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1482, https://doi.org/10.5194/egusphere-egu24-1482, 2024.

EGU24-1849 | ECS | Orals | ERE3.6

Effect of supply and demand conditions on the storage utilization for the ATES Triplet 

Thijs van Esch, Martin Bloemendal, Niels Hartog, and Phil Vardon

Space heating and cooling is responsible for roughly 25% of our final energy use, therefore it is a necessity to decarbonize our heating and cooling systems. Many technologies for space heating and cooling use a heat pump, making space heating and cooling more dependent on electricity. Since other sectors are similarly becoming more dependent on electricity, a main challenge in the energy transition is electricity grid congestion. This is even more a challenging issue given the season variation within heating and cooling demands.

                Hence, there is a need for a technology that disconnects the heating and cooling demand from electricity use. The Aquifer Thermal Energy Storage (ATES) Triplet is a technology that does just that. The ATES Triplet uses local sources for heating and cooling, such as solar collectors and dry coolers, and disconnects the temporal supply and demand asynchrony with subsurface storage. It has a hot well, for when the heat source either has too much or too little supply to match demand, a cold well for the time when a cold source has either too much or too little supply for direct cooling. Furthermore, it has a third well that prevents thermal pollution of the hot and cold well. Because of this integration, the ATES Triplet system can supply heating and cooling without a heat pump.

                Parametric simulations are presented to give insight into operational behaviour. A systematic variation of heating and cooling demands, injection temperatures, minimum operation temperatures and return temperatures gives insight into requirements to design and operate an efficient and reliable system. These parameters mostly influence either the heat recovery from the hot well, or the temperature in the third well. A lower heat recovery in the hot well results in a higher need for heat generation, and is mainly influenced by the heating demand, the injection temperature, and the cutoff temperature. A higher temperature in the third well results in a smaller need for heat generation, but a higher need for cold generation, and is influenced by the heating and cooling demands, and the return temperatures.

How to cite: van Esch, T., Bloemendal, M., Hartog, N., and Vardon, P.: Effect of supply and demand conditions on the storage utilization for the ATES Triplet, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1849, https://doi.org/10.5194/egusphere-egu24-1849, 2024.

EGU24-1876 | ECS | Posters on site | ERE3.6

Hydrogeological Characterisation of Sherwood Sandstone using BNMR and Geophysical Logs 

Sodiq Oguntade, Ulrich Ofterdinger, Jean-Christophe Comte, Ryan Gee, Myles Kynaston, and Robert Raine

The Sherwood Sandstone is an important aquifer for geothermal energy in Northern Ireland. The Northern Ireland Government has identified geothermal energy, including aquifer thermal energy storage (ATES) systems, as a viable green energy source. This study investigates the hydrogeologic characteristics of the Sherwood Sandstone, with a focus on its porosity, using borehole nuclear magnetic resonance (BNMR) and geophysical models (Archie and Waxman-Smits).

BNMR and geophysical logging were done inside three borehole installations drilled into the Sherwood Sandstone aquifer at a depth of about 100 m. The data (BNMR, resistivity log, EC log, temperature log, and natural gamma log) obtained from this exercise were analysed using WELLCAD.

The results of the processed data showed that the porosity calculated from the BNMR and the two petrophysical logs are similar, demonstrating the relationship between nuclear magnetic resonance and petrophysical-derived porosity. The average porosity of the Sherwood Sandstone at this location ranges between 19.9% and 14.5%, the minimum ranges between 2.1% and 9.9% and the maximum ranges between 42.5% and 30.2%.

This study confirmed the viability of Sherwood Sandstone for ATES systems, and further hydrogeologic characteristics such as hydraulic conductivity, transmissivity, and structure delineation are needed before its installation.

How to cite: Oguntade, S., Ofterdinger, U., Comte, J.-C., Gee, R., Kynaston, M., and Raine, R.: Hydrogeological Characterisation of Sherwood Sandstone using BNMR and Geophysical Logs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1876, https://doi.org/10.5194/egusphere-egu24-1876, 2024.

EGU24-1887 | ECS | Posters on site | ERE3.6

Sub-regional hydrothermal modelling of sedimentary reservoirs for high-temperature aquifer thermal storage potential exploration – Approach developed in PotAMMO 

Claire Bossennec, Max Ohagen, Jeoren van der Vaart, Niklas Scholliers, Hung Pham, Benedikt Herbert, Matthias Wolf, Adrian Einig, Denis Milde, and Ingo Sass

For efficient and economically viable heat storage solutions, and to enhance their integration into the energy mix for the heat supply of district heating networks, assessing and optimizing the potential of sedimentary reservoirs for high-temperature Aquifer Thermal Energy Storage (ATES) is a key aspect.

The PotAMMO project (BMBF, PtJ, FKZ: 03G0913B) methodologically integrates comprehensive geological exploration with dynamic hydrothermal modeling at the exploration phase for potential reservoirs and to provide realistic conditions for co-simulated ATES setup models (integrating district heating grids and subsurface thermo-hydraulic behavior). This integration is crucial for characterizing the potential of sedimentary reservoirs for high-temperature ATES, requiring sensitive parametrization of the boundary hydraulic conditions and thermal state of the reservoir. The exploration phase of PotAMMO emphasizes a thorough geological assessment, focusing on understanding the heterogeneity and complexity inherent in sedimentary environments. This phase includes detailed sedimentological and structural organization, which are essential for identifying potential reservoirs suitable for high-temperature ATES, along with their petrophysical and hydraulic properties.

Thus, sub-regional dynamic hydrothermal modelling is a cornerstone of the PotAMMO approach, aiming to simulate the complex interactions between heat and groundwater flow within these sedimentary reservoirs for two locations: the central northern Upper Rhine Graben for integration into the Mannheim district heating network, and the northern termination of the Upper Rhine Graben for the target Offenbach. This modeling is essential for understanding how the dynamic nature of the hydrothermal regime and processes in sedimentary reservoirs can affect ATES potential, and provides insights on where to place ATES wells for system efficiency optimally. The sub-regional model, the core of this contribution, and the ATES local models are run in FEFLOW on the basis of Petrel-built grids and the district heating grid is simulated in Modelica. A simplified case study for the co-simulation is also presented here.

This approach intends to overcome the challenge of integrating geological complexity and heterogeneity with the typically sparse data available for these environments and localities. Stochastic modeling is used to manage geological uncertainty and effectively interpolate data. This allows for a nuanced representation of the subsurface, enhancing the reliability of hydrothermal models and rock property distributions.

By combining detailed geological exploration with advanced dynamic hydrothermal modeling, PotAMMO addresses the challenges of geological complexity, heterogeneity, and data scarcity. This approach is essential in paving the way for more efficient and realistic assessments of ATES potential, thereby contributing significantly to the advancement of sustainable energy storage solutions and their integration into large-scale district heating grids, for significant decarbonization of the heat supply.

How to cite: Bossennec, C., Ohagen, M., van der Vaart, J., Scholliers, N., Pham, H., Herbert, B., Wolf, M., Einig, A., Milde, D., and Sass, I.: Sub-regional hydrothermal modelling of sedimentary reservoirs for high-temperature aquifer thermal storage potential exploration – Approach developed in PotAMMO, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1887, https://doi.org/10.5194/egusphere-egu24-1887, 2024.

EGU24-2196 | Orals | ERE3.6

Exploring the feasibility of uni-directional ATES in high ambient groundwater flow aquifers 

Valerio Silvestri, Martin Bloemendal, Giovanni Crosta, and Alberto Previati

In the context where the member states of the European Union are asked to reach the goal of net zero emission of greenhouse gases before 2050, many cities all over Europe are adopting sustainable energy systems. One of the primary sources of CO2 emission are building heating and cooling systems. As aquifers are commonly present in many urban areas, ground coupled heat pumps are a renewable solution that many countries are adopting to replace fossil based heating and cooling techniques.

Aquifer thermal energy storage (ATES) is attained by storing thermal energy in groundwater aquifers. Hence, a key aquifer characteristic for ATES is the natural groundwater flow velocity. For velocities less than 25 m/y, bi-directional ATES is usually possible. For groundwater flow velocities greater than 25 m/y, ATES is still possible, but requires multiple doublets with a specific well placement to be able to compensate for the groundwater flow via upstream injection and downstream extraction. Alternatively, “pump and dump” systems, which generate thermal plumes that affect the downstream groundwater temperature and are not desirable for other users, are adopted.

A possible way to tackle the issue of aquifers with high ambient groundwater flow velocity is to combine the two solutions described above by applying a uni-directional pumping scheme allowing to compensate for the groundwater flow by constantly injecting in the upstream well and extracting from the downstream well. Spacing of the wells should be adjusted to the storage cycle length and natural groundwater flow velocity to ensure re-capture the energy injected within the aquifer in the previous season from the upstream well and transported to the down-gradient extraction well by the groundwater flow. This concept would also mitigate the downstream effect of a thermal plume. In this research the results of a sensitivity and feasibility analysis of this concept are presented. The results show that optimal inter-well distance not only depends on storage cycle length and groundwater flow velocity, but also on storage volume. Downstream thermal pollution can be avoided and recovery of the heat/cold stored can reach values between 50-60% depending on the conditions.

How to cite: Silvestri, V., Bloemendal, M., Crosta, G., and Previati, A.: Exploring the feasibility of uni-directional ATES in high ambient groundwater flow aquifers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2196, https://doi.org/10.5194/egusphere-egu24-2196, 2024.

EGU24-2421 | ECS | Orals | ERE3.6

Sand as a thermal energy storage material for solar thermal technologies 

Omar Radwan and John Humphrey

Sand, an inexpensive and abundantly available natural geomaterial, holds promise as a thermal energy storage (TES) material in diverse solar thermal systems such as concentrated solar power, solar heating, and solar gasification. Sand possesses the ability to capture solar radiation during daylight hours, preserving it as heat on both a daily and seasonal basis, and then releasing it when demand is high. Although sand exhibits lower thermal conductivity and specific heat capacity when compared to molten salt and engineered TES materials, it compensates for these drawbacks by withstanding high temperatures and being economically advantageous.

For sand to effectively function as a TES medium, it needs to acquire a high energy density. This entails a considerable specific heat capacity and resilience to substantial temperature variations. Optimal for this purpose, pure quartz sand stands out due to its elevated specific heat capacity, high thermal conductivity, and its ability to maintain integrity without agglomerating or degrading even at temperatures exceeding 1000°C. Impurities adversely affect the energy density of sand. The presence of clays, carbonates, and feldspars has been identified as leading to premature agglomeration, early degradation, and/or reduced specific heat capacity in sands. At a temperature of 600°C, clays were observed to enhance the tendency of sand to agglomerate, with agglomeration increasing with rising temperature and pressure. Below 800°C, carbonate minerals undergo decarbonization, resulting in mass loss and alterations in grain-size distribution. For instance, calcite grains transform into lime powder, which exhibits an extremely low specific heat capacity. Below 1200°C, feldspars undergo vitrification, leading to agglomeration that hinders fluidization and the flow of sand through the system. To avoid these complications, it is imperative to limit impurities to less than 2%.

How to cite: Radwan, O. and Humphrey, J.: Sand as a thermal energy storage material for solar thermal technologies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2421, https://doi.org/10.5194/egusphere-egu24-2421, 2024.

EGU24-4305 | ECS | Posters on site | ERE3.6

Multi-scale Investigation of a Triassic Sherwood Sandstone Aquifer and Its Impact on Aquifer Thermal Energy Storage 

Shuangyi Gong, Kevin Taylor, and Lin Ma

The transition of energy supply from mainly fossil sources to low-carbon energy sources is essential for future environmental sustainability. The current worldwide energy demand for heating and cooling in buildings accounts for 40% of the primary energy consumption. The use of aquifer thermal energy storage (ATES) is predicted to play an increasing role as a regenerative energy source. The Triassic Sherwood Sandstone aquifer is the second most important aquifer in England and Wales, providing about 25% of groundwater resources. Hence, understanding its aquifer characteristics is important for assessing the suitability of its use for ATES.

This study utilizes samples of the Permo-Triassic Sherwood Sandstone from the Abbey Arms Wood borehole in Delamere, Cheshire, UK. This borehole was drilled to approximately 150m and penetrates the Helsby and Wilmslow Formation. The samples are selected from 5 major facies (coarse- and fine-grained fluvial channel fill sandstones, sandy sabkha, sand sheet and dune aeolian sandstones, and massive sandstone facies).

 XRD data show that samples are mainly composed of quartz, feldspar, and muscovite, with minor calcite and hematite, with some accessory phases. Quartz contents are between 58.4%- 88.6%, with an average of 76.9%. Feldspar contents are between 6.0%-23.9%, 16.0% in average. Muscovite contents are in the range of 3.3%-12.5%, the mean value is 5.6%. Thin section observation shows that selected Sherwood sandstone samples are characterized by high quartz and feldspar content with few lithic fragments, and hematite coatings are well-developed around mineral grains. The dominant sandstone types are arkose (37.5%) and lithic arkose (18.8%).

The porosity of the samples is between 19.2%-26.2%, with the majority being more than 20%. The permeability is between 3.6*10-14and 1.2*10-11m, mean value is 2.2*10-12m. At room temperature, the testing of 14 samples of the Sherwood sandstone group found that the average intrinsic thermal conductivity is 1.4 w/mK, thermal diffusivity is 1.2 mm2/s and heat capacity is 0.7 J/gK. The physical properties of each lithofacies show subtle systematic differences, with the fluvial sandstone facies and massive sandstone facies having a relatively higher permeability and thermal conductivity. However, significant heterogeneity is not present, suggesting that this aquifer is a good target for ATES.

How to cite: Gong, S., Taylor, K., and Ma, L.: Multi-scale Investigation of a Triassic Sherwood Sandstone Aquifer and Its Impact on Aquifer Thermal Energy Storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4305, https://doi.org/10.5194/egusphere-egu24-4305, 2024.

EGU24-5318 | ECS | Orals | ERE3.6

Local thermal non-equilibrium in heterogeneous porous media identified through 3D heat transport modelling 

Hannah Gebhardt, Alraune Zech, Gabriel Rau, and Peter Bayer

Modelling heat transport in porous aquifers is generally based on the assumption of an instantaneous local thermal equilibrium (LTE) between the solid and the fluid phase. Previous studies have revealed that this assumption can be violated, e.g. in the presence of fast or preferential flow causing delayed heat diffusion into the grain structure matrix, referred to as local thermal non-equilibrium (LTNE). However, conditions and scales at which LTNE effects should be taken into account in natural heterogeneous sediments are almost unexplored. We study the relation between macro-scale heterogeneity, thermal dispersion and LTNE through numerical simulations of heat transport in three-dimensional heterogeneous hydraulic conductivity fields. The advection-diffusion equation is solved using the Multiphysics Object-Oriented Simulation Environment (MOOSE), an open-source, parallel finite element framework. The spatial and temporal evolution of the heat plume generated by a line source under steady-state flow conditions is examined. For understanding the propagation of heat plumes, the role of delayed diffusion caused by LTNE effects needs to be distinguished from hydro-mechanical dispersion. Therefore, we estimate the thermal dispersion and the effective thermal retardation for each time step using a stochastic approach. LTNE effects are present, when the effective thermal retardation deviates from the predicted, apparent thermal retardation. Simulations show good agreement between the effective and the apparent thermal retardation for homogeneous hydraulic conductivity. With increasing heterogeneity, characterized by a higher variance of the log-conductivity, the effective retardation becomes lower than the apparent retardation at early times. Furthermore, we estimate the effective thermal retardation for a homogeneous flow field with added thermal dispersion based on the dispersion coefficients resulting from the heterogeneous simulations. We find that there is a significant difference in the evolution of effective retardation between the homogeneous and the heterogeneous case both of the same thermal dispersion, which we associate to LTNE effects. Our modelling approach thus allows to quantify LTNE induced by field-scale heterogeneity.

How to cite: Gebhardt, H., Zech, A., Rau, G., and Bayer, P.: Local thermal non-equilibrium in heterogeneous porous media identified through 3D heat transport modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5318, https://doi.org/10.5194/egusphere-egu24-5318, 2024.

EGU24-6643 | ECS | Posters on site | ERE3.6

System of devices for accumulation of excess heat in the natural water-permeable layer and for its recovery – modeling results 

Marek L. Solecki, Tadeusz Solecki, Jerzy M. Stopa, Rafał Wiśniowski, Marek Hajto, and Rafał Smulski

A system of devices for accumulating excess heat in a natural water-permeable layer and for its recovery, applicable in underground heat storage, especially in its effective use, is presented. This system ensures high efficiency and low thermal inertia, and at the same time eliminates the disadvantage of the known method of storing heat in natural water-permeable layers - Aquifer Thermal Energy Storage (ATES), which consists in the impossibility of using it in water-permeable layers with low water content or with significant dynamics of water flow in the area designated as heat storage.

The system of devices for accumulating excess heat in the natural water-permeable layer and for its recovery is a heat accumulator filled with water, which is a closed area separated from the water-permeable layer using anti-filtration walls, which are also a thermally insulating partition.

The system includes a surface heat exchanger and extraction and discharge wells located in the battery area, used to accumulate and remove heat, equipped with deep-well pumps. The extraction and discharge wells also contain multi-level temperature and water level measurement probes, signal-connected to the control, measurement, and control equipment that controls the operation of deep-well pumps and controllable valves located on the hydraulic lines connecting the well system with the heat exchanger.

The solution can be used as a seasonal heat and/or cold storage using geotechnical structures such as sheet piling, as well as a dedicated solution for storing excess heat/cold to support existing urban heating systems.

The device concept has obtained the European patent EP4063780B1.

The results of modeling the heat storage operation performed in the Petrel and Eclipse software by Schlumberger are presented.

How to cite: Solecki, M. L., Solecki, T., Stopa, J. M., Wiśniowski, R., Hajto, M., and Smulski, R.: System of devices for accumulation of excess heat in the natural water-permeable layer and for its recovery – modeling results, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6643, https://doi.org/10.5194/egusphere-egu24-6643, 2024.

EGU24-7451 | Orals | ERE3.6 | Highlight

Prospects for Aquifer Thermal Energy Storage in the UK 

Matthew Jackson, Geraldine Regnier, and Iain Staffell

Aquifer Thermal Energy Storage (ATES) is an underground thermal energy storage technology that provides large capacity (of order MWth to 10s MWth), low carbon heating and cooling to large buildings or complexes of buildings, or district heating/cooling networks.  The technology operates through seasonal capture, storage and re-use of thermal energy in shallow aquifers, reducing carbon emissions and electricity demand for heating and cooling compared to direct ground- or air-sourced heat pump systems.

We demonstrate that ATES could make a significant contribution to decarbonising UK heating and cooling, but uptake is currently very low.  We identify eleven low temperature (LT-ATES) systems operating in the UK, with the first having been installed in 2006. These systems currently meet <0.01% of the UK’s heating and <0.5% of cooling demand.  Despite the current low uptake, the UK has large potential for widespread deployment of LT-ATES, due to its seasonal climate and the wide availability of suitable aquifers which are co-located with urban centres of high heating and cooling demand.  We use a probabilistic approach to estimate that ATES could supply approximately 64.5 % of current UK heating demand, and 80 % of cooling demand.  

A key barrier to increasing UK uptake is lack of awareness of the technology.  We analyse the performance of a successful UK installation, and also report installations in which problems with design and operation have caused sub-optimal performance.  The UK can benefit from experience of both successful and unsuccessful deployments but these need to be more widely reported.

How to cite: Jackson, M., Regnier, G., and Staffell, I.: Prospects for Aquifer Thermal Energy Storage in the UK, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7451, https://doi.org/10.5194/egusphere-egu24-7451, 2024.

EGU24-8027 | ECS | Orals | ERE3.6

Evaluation of the mine thermal energy storage potential with a stochastic discrete fracture matrix model 

Chaofan Chen, Martin Binder, Lukas Oppelt, Yingtao Hu, Christian Engelmann, Alireza Arab, Wenjie Xu, Traugott Scheytt, and Thomas Nagel

Decarbonizing the industrial and building heating and cooling sectors is a crucial step toward achieving carbon neutrality, necessitating innovative and sustainable solutions for the over-seasonal storage of excess heat energy. With Germany alone having more than 10,000 old mines, repurposing these sites to implement a controlled thermal energy storage strategy, known as mine-based thermal energy storage (TES), has emerged as a potential solution. To effectively utilize such partially flooded artificial cavities, it is crucial to fully understand the heat transport and storage behavior in these systems.

In this work, a three-dimensional hydro-thermo-component (HTC) model was developed using the open-source simulation code OpenGeoSys (OGS). The model was initially verified against analytical solutions for the single fracture flow of heat and solute transport, respectively. Subsequently, stochastic discrete fracture matrix (DFM) geometries and meshes were generated using the computational suite Frackit, based on data from a pilot heat storage site in a water-filled mining cavity in Freiberg, Germany. This test site is geologically characterized as the Freiberg gneiss, a metamorphic fractured rock formation.

The developed setup allows for investigating the thermal energy storage capacity and the energy recovery efficiency based on process simulations in OGS. The study evaluated the thermally affected zone in the fractured formation and quantified the amount of heat stored and recovered during cyclic operation. In addition, the solute transport distance within the surrounding rock can be evaluated under different hydraulic conditions. The general modeling workflow provides a basis for conducting techno-economic feasibility analysis of mine-based TES systems.

How to cite: Chen, C., Binder, M., Oppelt, L., Hu, Y., Engelmann, C., Arab, A., Xu, W., Scheytt, T., and Nagel, T.: Evaluation of the mine thermal energy storage potential with a stochastic discrete fracture matrix model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8027, https://doi.org/10.5194/egusphere-egu24-8027, 2024.

EGU24-9196 | ECS | Orals | ERE3.6

Policies for Aquifer Thermal Energy Storage (ATES) 

Ruben Stemmle, Richard Hanna, Kathrin Menberg, Poul Alberg Østergaard, Matthew Jackson, Iain Staffell, and Philipp Blum

Aquifer thermal energy storage (ATES) is a promising technology for sustainable and climate-friendly space heating and cooling. Compared to conventional heating and cooling techniques, ATES-based systems offer several benefits such as lower greenhouse gas emissions and reduced primary energy consumption. Despite these benefits and the availability of suitable aquifers in many places around the world, ATES has yet to see a widespread global utilization. Currently the vast majority of installed systems is located in the Netherlands, Belgium, Sweden and Denmark. Besides technical and hydrogeological feasibility, appropriate national policies driving ATES deployment are therefore of high importance. Hence, this study provides an international comparison of ATES policies, highlighting best practice examples and revealing where appropriate policy measures are missing. To this end, multi-disciplinary views from experts in geothermal energy and ATES from academia, companies, government authorities, national geological surveys and industrial associations in 30 countries were obtained through an online survey. Subsequent semi-structured interviews with a smaller selection of experts revealed further insights. The online survey results show significant differences regarding the existence and the strength of supporting policy elements between countries of different ATES market maturity. Going beyond these descriptive findings, the interviews provided more country-specific details on how favorable conditions came into effect and what obstacles have still to be overcome for an increased ATES deployment. Based on the lessons learned from the online survey and the expert interviews, recommendations for sophisticated ATES policies are derived which address the following areas: legislative and regulatory issues, raising awareness and expertise, the role of ATES in local energy transitions, and social engagement. This work aims at steering energy policy towards a wider international ATES deployment and better harnessing the potential of ATES to decarbonize buildings.

How to cite: Stemmle, R., Hanna, R., Menberg, K., Østergaard, P. A., Jackson, M., Staffell, I., and Blum, P.: Policies for Aquifer Thermal Energy Storage (ATES), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9196, https://doi.org/10.5194/egusphere-egu24-9196, 2024.

EGU24-9285 | ECS | Orals | ERE3.6

Impact of Aquifer Heterogeneity on LT-ATES Performance: A Case Study from the Chalk Aquifer, London, UK 

Hayley Firth, Carl Jacquemyn, Gary Hampson, and Matthew Jackson

The Chalk comprises a highly heterogeneous dual porosity aquifer, characterized by intervals of high permeability formed by fracturing and/or karstification of a low-permeability matrix. Many boreholes in London show evidence of a high-permeability flow zone at the top of the Chalk. Despite this, models used to predict ATES system operation in the Chalk aquifer in London have typically assumed a homogeneous aquifer, so that simulated warm and cold plumes have a simple cylindrical geometry around the wells. In this study, we investigate the impact of aquifer heterogeneity on system operation.

We examine an operating LT-ATES installation. The system employs 4 cold wells and 4 warm wells and is sized to deliver peak heating of 1.8 MW and peak cooling of 2.75 MW. Analysis of flowrate and temperature data shows that the system has a well-balanced energy ratio of 0.09 and exhibits a low but increasing thermal recovery which is currently ca. 40% for warm storage and 25% for cold storage.

We use a Surface-Based Modelling (SBM) approach to represent geological heterogeneity, which allows us to accurately and realistically capture geometrically complex subsurface features. We develop a range of parametrised 3D models of different geological scenarios, to capture uncertainty in geological heterogeneity between the wells. Flow and heat transport during ATES operation are simulated using the Imperial College Finite Element Reservoir Simulator (IC-FERST). The models are calibrated using Nelder-Mead methods to match pressure transient data and well inflow logs obtained from the boreholes prior to commissioning. Temperature and flowrate data collected during operation are subsequently employed in thermal simulations using the calibrated models.

Our findings suggest that aquifer heterogeneity has a significant impact on the formation of the warm and cold plumes. Heterogeneity has resulted in a thermal recovery bias toward warm water, despite ambient aquifer temperature being closer to the injected cool water temperature. Two high-permeability intervals play a pivotal role in the development of pancake-shaped plumes, as opposed to simple cylindrical plumes. Greater conductive heat losses to the overlying and underlying rock is observed with pancake-shaped plumes, resulting in lower thermal recovery. Recovery is predicted to increase as the temperature of the surrounding rock gradually changes through time. Heating and cooling demand on the ATES system is generally low, so the system predominantly utilizes just a single well doublet, with the choice of operational doublets varying through time. Thermal interference between the warm and cold wells in a given operating doublet may result from the laterally extensive plume geometry.

Our results indicate the necessity of recognising and modelling subsurface heterogeneity prior to ATES operation in areas with fractured and/or karstified aquifers. Designing effective operational plans entails incorporating considerations of local heterogeneity. Our insights have broad implications for future planning and design of ATES systems in the UK and globally.

How to cite: Firth, H., Jacquemyn, C., Hampson, G., and Jackson, M.: Impact of Aquifer Heterogeneity on LT-ATES Performance: A Case Study from the Chalk Aquifer, London, UK, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9285, https://doi.org/10.5194/egusphere-egu24-9285, 2024.

EGU24-9394 | Orals | ERE3.6

Modelling the feasibility of using disused mines for heat extraction and storage 

Jeroen van Hunen, Julien Mouli-Castillo, Alexandra Sweeney, jiada Tu, Yuxiao Wang, and Charlotte Adams

The subsurface offers significant opportunities for geothermal heat extraction and storage. Disused, flooded coal mines, in particular, are capable of providing a major low-enthalpy, renewable and long-term heat resource if carefully managed. To establish a mine water geothermal system requires significant capital investment and a large amount of time. Therefore, a solid investigation of the feasibility of a mine as heat source or storage medium is essential.

We have developed a modelling tool, GEMSToolbox, to investigate the feasibility of abandoned mines for long-term heat extraction and/or storage. This tool allows for a computationally fast and a low-cost study into the viability of mine water heating for given mine workings. We combine numerical and analytical methods with digitised legacy mine plan data to estimate the variations in the abstraction water temperature over the lifetime of a project. We couple the heat transfer approximation method originally proposed by Rodriguez and Diaz (2009) to that of flow in a pipe network as described by Todini and Pilati (1987), and refine the original heat transfer approximation by accounting for a flow regime specific heat transfer coefficient between the rock mass and the water, as prescribed by Loredo et al. (2017). A novel weighting function is also developed to account for the interference between adjacent mine galleries. This tool has been successfully applied to a range of mine system in the North East of England, and the results of this study are used to draw widely applicable conclusions on the feasibility of mine workings for heat extraction or storage more generally.

References:

  • Loredo C, Banks D, Roqueñí N. Evaluation of analytical models for heat transfer in mine tunnels. Geothermics 2017; 69; 153-164.
  • Rodriguez R and Díaz M. Analysis of the utilization of mine galleries as geothermal heat exchangers by means a semi-empirical prediction method. Renewable Energy 2009; 34(7), 1716-1725.
  • Todini E and Pilati S. A gradient method for the analysis of pipe networks. Computer app. In water supply 1987; 1-20, v1.

How to cite: van Hunen, J., Mouli-Castillo, J., Sweeney, A., Tu, J., Wang, Y., and Adams, C.: Modelling the feasibility of using disused mines for heat extraction and storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9394, https://doi.org/10.5194/egusphere-egu24-9394, 2024.

EGU24-10957 | Posters on site | ERE3.6

Water concerns in UTES: what can be learnt from geothermal experience & what issues need to be specifically addressed? 

Annick Loschetter, Maud Watkinson, Simona Regenspurg, Setareh Rad, Laurent André, Arnault Lassin, Guido Blöcher, Sylvain Stéphant, Niels Hartog, Martin van der Schans, and Philip J. Vardon

The European project PUSH-IT’s ambition is to overcome the seasonal mismatch between heat demand and heat generation from sustainable sources using Underground Thermal Energy Storage (UTES) at high temperatures, i.e. up to 90°C (https://www.push-it-thermalstorage.eu). PUSH-IT showcases three UTES technologies at six pilot sites: Aquifer Thermal Energy Storage (ATES) in the Netherlands and Germany, Mine Thermal Energy Storage (MTES) in Germany and the UK, and Borehole Thermal Energy Storage (BTES) in Germany and the Czech Republic.

Water quality issues represent technical challenges for viable long-term thermal energy storage, whatever the technology. These include:

  • Biogeochemical perturbations in the storage reservoir: the temperature gradient influences the chemical composition of the fluids that may lead to (bio)clogging in near-wells and loss of injectivity/productivity, notably for ATES;
  • Corrosion and scaling in the wells and facilities;
  • Shallower aquifer perturbation by temperature increase and saline brines from deeper aquifers.

The lessons learnt over decades of geothermal exploitation and low temperature thermal energy storage provide a solid basis for anticipating, monitoring, managing and remediating these issues in a variety of geological contexts. However, for increasing the temperatures of thermal energy storage in geothermal reservoirs several specificities have not been thoroughly investigated, such as the thermal storage at high temperature, the need to use reversible wells, reversible fluxes in the reservoir, temperature and pressure cycling. Furthermore, the role of microbiology has often been neglected and is anticipated to be more sensitive in storage applications.

At the current stage of the project, the main concerns for each site have been mapped. The modelling and monitoring works are at different stages of progress depending on the sites. Significant methodological work is being carried out on microbiological phenomena and on the elaboration of monitoring protocols.

The project will go beyond the simple feedback on the experience from pilot sites by providing recommendations to anticipate and deal with water quality issues for future sites. We will provide guidelines to assist decision-makers in identifying the main issues, in implementing the necessary modelling, in sizing and adjusting the monitoring plan, in assessing possible water treatment benefit vs. environmental impact. Anticipating and managing water-related issues as far as possible is the best way of making the right choices, guaranteeing the performance and longevity of operations, limiting environmental impact and encouraging society engagement and support.

 

Acknowledgements: Funded by the European Union under grant agreement 1011096566 (PUSH-IT project). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or CINEA. Neither the European Union nor CINEA can be held responsible for them.

How to cite: Loschetter, A., Watkinson, M., Regenspurg, S., Rad, S., André, L., Lassin, A., Blöcher, G., Stéphant, S., Hartog, N., van der Schans, M., and Vardon, P. J.: Water concerns in UTES: what can be learnt from geothermal experience & what issues need to be specifically addressed?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10957, https://doi.org/10.5194/egusphere-egu24-10957, 2024.

High Temperature Aquifer Thermal Energy Storage (HT-ATES) allows the large scale seasonal storage of sustainable heat available in summer, enabling its utilization in winter, hence reducing GHG emissions. The feasibility and potential of HT-ATES systems is largely determined by its recovery efficiency. The stored groundwater, at 40 to 80 °C higher temperature than the ambient groundwater, has a relatively low density and viscosity. The differences in density and viscosity between the stored and ambient groundwater create the potential for buoyancy-driven flow to the top of the aquifer during storage, which may lead to increased heat losses during recovery as commonly observed in earlier HT-ATES studies. Conventionally, these studies assume an uniform in- and outflow distribution of water through the well screen during injection and extraction. However, as density and viscosity changes also affect the pressure state in the well and influence the flow resistance of the aquifer, the flow distribution through the well screen is potentially impacted by these changes of density an viscosity, especially at higher storage temperatures. Therefore, this study addresses the effect of density and viscosity differences on the flow distribution through HT-ATES screens during injection and extraction for relevant storage conditions, and further assesses its impact on heat recovery compared to simulations including uniform well flow distribution. Results show that, due to both density and viscosity changes at high storage temperature, the flow distribution through the well screen may be significantly changed depending on mainly the hydrogeological and well operating conditions. Compared to HT-ATES simulations with uniform flow distribution, increased thermal recovery efficiencies are observed ranging from 0 – 8% in the 5th year of operation for the varied conditions in this study.

How to cite: Beernink, S., Hartog, N., Vardon, P. J., and Bloemendal, M.: How temperature-induced density and viscosity differences affect the flow distribution through well screens and may influence heat recovery of HT-ATES systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10981, https://doi.org/10.5194/egusphere-egu24-10981, 2024.

EGU24-11654 | Orals | ERE3.6

Heat storage in abandoned coal mine shafts in Scotland 

Jessica Dassow, Ian Molnar, Neil Burnside, Win Eng Ewe, Graeme Flett, Stephanie Flude, Indrani Mukherjee, Paul Tuohy, Huachuan Wang, Daniel Whittington, Shangtong Yang, and Zoe Shipton

Following an increase in demand and extent of renewable energy systems, one of the most urgent challenges in the energy transition is the storage of intermittent renewable energy. Storage would enable continuous energy supply and ease current difficulties in balancing the energy grid. For example, it is estimated that the UK spent over £500 million on wind energy curtailment payments in 2023, wasting thousands of GWh during valuable high output times. This curtailed wind energy could be stored as Underground Thermal Energy (UTES) and utilised when demand increases and outstrips production. Hundreds of abandoned legacy mine shafts across the UK contain a large volume of water and concrete lining surrounded by low permeability rocks, suggesting they can be used as valuable pre-existing structures for low-cost heat storage systems. The locality, availability and volume of flooded mine shafts make them an interesting asset of energy storage for space heating and cooling especially in Scotland.

The STEaM project (Subsurface Thermal Energy storAge: Engineered structures and legacy Mine shafts) is investigating the challenges and safety of heat storage in abandoned coal mine shafts that have refilled with water via a joint experimental/modelling investigation and an upcoming pilot project at a legacy mineshaft in Scotland. While the overall project includes hydrogeochemical analysis, energy systems modelling, as well as mechanical and material investigation, this presentation focuses on simulating the coupled hydro-thermal-mechanical processes impacting the shaft and near-field environment such as e.g., development of natural convection cells. Specifically, this presentation will showcase a modelling sensitivity analysis of some of the common variabilities in mine shafts (such as shaft dimension, geology and groundwater flow) to evaluate heat storage efficiency for cyclic heating and cooling. Basis for the presented model is a 3D finite element analysis with COMSOL to study spatial and temporal developments of heat gain and loss underground.

How to cite: Dassow, J., Molnar, I., Burnside, N., Ewe, W. E., Flett, G., Flude, S., Mukherjee, I., Tuohy, P., Wang, H., Whittington, D., Yang, S., and Shipton, Z.: Heat storage in abandoned coal mine shafts in Scotland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11654, https://doi.org/10.5194/egusphere-egu24-11654, 2024.

EGU24-13438 | Orals | ERE3.6

Techno-economic assessment of high-temperature aquifer thermal energy storage system, insights from a study case in Burgwedel, Germany 

Dejian Zhou, Ke Li, Huhao Gao, Alexandru Tatomir, and Martin Sauter

To mitigate the increasing greenhouse gas emissions, the technology of high-temperature aquifer thermal energy storage system (HT-ATES) is attracting the public’s attention as an alternative to traditional fossil fuels for domestic heating and cooling. Based on a wellbore model and a reservoir model, we did a comprehensive economic assessment of the target HT-ATES planning in Burgwedel near Hannover, Germany. The levelized cost of heat (LCOH), payback time, and CO2 emission reduction are selected to assess the HT-ATES performance. Results show that the total energy loss during the stages of injection, production and reservoir storage is ca. 9%, of which ca. 2.7% during injection, ca. 2.2% during production, and ca. 4% within the reservoir. Provided that the heat exchange efficiency between the subsurface part and end-use system is 70%, the HT-ATES starts to profit from the 3rd operation year with 30-year LCOH of nearly 2.3 cent per kWh, similar to the currently running ATESs. The 30-year net CO2 emission reduction is ca. 58.1 kt with an average of ca. 1937 t/year, which is more considerable than the low-temperature ATES, i.e., ranging from 150 and 1500 t/year. The economic assessment of the HT-ATES indicates that the planning project can provide heating and cooling services for the district of Burgwedel with lower price and CO2 emission.

How to cite: Zhou, D., Li, K., Gao, H., Tatomir, A., and Sauter, M.: Techno-economic assessment of high-temperature aquifer thermal energy storage system, insights from a study case in Burgwedel, Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13438, https://doi.org/10.5194/egusphere-egu24-13438, 2024.

EGU24-14989 | Orals | ERE3.6

High-Temperature Aquifer Thermal Energy Storage (HT-ATES) system for research development and demonstration on the TU Delft campus 

Philip Vardon, Martin van der Schans, Alexis Koulidis, Tessel Grubben, Stijn Beernink, and Martin Bloemendal

At present, over half of all primary energy used in Europe is used for heating and cooling. Therefore, decarbonizing the heating supply is essential to achieve climate targets.  Underground thermal energy storage is a key enabling technology for the energy transition to buffer the large seasonal mismatch between thermal energy demand and sustainable thermal energy production capabilities. In Delft, a High-Temperature Aquifer Thermal Energy Storage (HT-ATES) system will be installed at the campus of Delft University of Technology (TU Delft). It will be integrated in the wider heating system on and around the TU Delft campus, which itself is undergoing a transformation to optimally supply sustainable thermal energy. The district heating network will be extended and utilize the thermal energy from a geothermal doublet producing heat at around 75-80°C with a flow rate of ~350m3/hr. Excess energy produced by the geothermal well in summer will be stored in the HT-ATES system, and will be utilised when demand exceeds production throughout the winter. The HT-ATES system will comprise of 7 wells (3 hot wells of 80°C and 4 warm wells of 50°C) to a depth of approximately 200m, with storage in an unconsolidated sedimentary aquifer between 160-200m depth. It is designed so that the instantaneous excess power from the geothermal project can be stored and demand from the district heating network be extracted from the system.  

The HT-ATES system at TU Delft is partially funded by local stakeholders and the European commission within the PUSH-IT project and has two primary goals: (i) to reduce carbon emissions on TU Delft campus , and (ii) to create a unique demonstration, education and research infrastructure. The complexity of a HT-ATES requires innovative solutions during the entire system life cycle.  The scientific programme that is initially planned within the project is therefore focusing on various research fields and includes:
- Characterisation of the subsurface formations including mechanical, hydraulic, thermal, and chemical properties.

- Evaluation and monitoring of the biological conditions and microbial diversity, and potential impact on water quality.

- Innovations in drilling and completion, monitoring and performance.

- Quantification of the system performance and system impact during multiple storage cycles and the full lifecycle of the HT-ATES. This will include extensively monitoring temperature distribution and water quality in the subsurface to characterise behaviour and improve models.

- Demonstrate and develop the implementation of HT-ATES in an urban setting,  including control of the system in the built-environment and transforming the conventional heat network to a future-proof  heat network.

- To allow access to other universities or institutions with active programmes in the field of Geothermal Science and Engineering to jointly carry out research and perform experiments.

-Societal engagement and legal evaluation for improving the just energy transition.

 

Acknowledgements: Funded by the European Union under grant agreement 1011096566 (PUSH-IT project). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or CINEA. Neither the European Union nor CINEA can be held responsible for them.

How to cite: Vardon, P., van der Schans, M., Koulidis, A., Grubben, T., Beernink, S., and Bloemendal, M.: High-Temperature Aquifer Thermal Energy Storage (HT-ATES) system for research development and demonstration on the TU Delft campus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14989, https://doi.org/10.5194/egusphere-egu24-14989, 2024.

EGU24-15006 | ECS | Orals | ERE3.6

Enhanced closed-loop underground thermal energy storage systems, using experimental materials via numerical modelling and laboratory analysis 

Sara Franzè, Francesca Martelletto, Giorgia Dalla Santa, Fatemeh Isania, Paolo Scotton, Luca Doretti, and Antonio Galgaro

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used at a later time for heating and cooling applications and power generation.  TES systems can be divided into three main categories: sensible heat storage (SHS), thermochemical storage (TCS) and latent heat storage (LHS) associated with phase-change materials (PCMs). PCMs are able to release or absorb thermal energy changing their physical state at a quite constant temperature.
This work aims to analyse the properties of different PCMs and supporting materials to be used coupled in closed-loop underground thermal energy storage (UTES) system. The physical and thermal properties of different PCMs (from lower to medium – high temperature) and their supporting materials, in particular diatoms, are analysed separately through laboratory analysis and numerical modelling, in order to find out the best material providing high thermal conductivity and capacity, efficiency, durability and low cost. However, research is also open to other types of materials such as graphene, zeolites, carbon nanotube and biochar.
Then, the best performances PCM is tested to define the best mix between PCMs (the capacitive part) and diatoms (part that will prevent the leakage during the phase change) under different boundary conditions. With the best mix, combined with cement, cylindrical samples 30 cm in diameter and 1 m in length will be constructed with the patented mixtures with a metallic finned tube inserted within it, to represent a thermal storage mass with a tube inside.
This sample will be tested, for low-temperature experiments (below 100 °C), using water as carrier fluid, in a physical model hosted at the UNIPD laboratory constituted by a box (1 m3 volume) that can be filled with dry or saturated loose materials with a metallic tube inserted in the middle to represent the heat exchange between the water flowing in the tube at a certain temperature, and the surrounding material, under different boundary conditions. The experimental device, allows to assess, under controlled conditions, the evolution in time and space of the energetic processes that occur between an heat exchanger and the surrounding ground. A second sample with similar characteristics, on the other hand, will be tested with high temperatures (between 200 °C and 300 °C) using a diathermic oil as heat transfer fluid and will be tested in a different device with a high-temperature heating system. The experimental data obtained will be also used in the construction and calibration process of numerical models by using commercial software (FEFLOW).
Finally, the simulation results are expected to identify the best conditions to apply the new conceived mix in a real test site.

How to cite: Franzè, S., Martelletto, F., Dalla Santa, G., Isania, F., Scotton, P., Doretti, L., and Galgaro, A.: Enhanced closed-loop underground thermal energy storage systems, using experimental materials via numerical modelling and laboratory analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15006, https://doi.org/10.5194/egusphere-egu24-15006, 2024.

EGU24-16554 | Posters on site | ERE3.6

Current research on Aquifer Thermal Energy Storage in Germany 

Kathrin Menberg, Ruben Stemmle, Sebastian Bauer, Peter Bayer, Guido Blöcher, Stefan Kranz, Clemens Felsmann, Florian Hahn, Haibing Shao, Kai Zosseder, and Philipp Blum

Around 30 % of Germany's final energy consumption can be attributed to heating and cooling in the building sector. Aquifer Thermal Energy Storage (ATES) allows sustainable and climate-friendly space heating and cooling and is therefore a promising technology that can contribute to decarbonizing this sector. However, further research on ATES is needed to promote the so far limited application of this technology in Germany and other countries. This work therefore gives an overview of current ATES research sites and projects in Germany collected in the project ‘SpeicherCity’. Among other aspects, these projects address hydrogeochemical challenges, potential studies and the integration of ATES into existing energy systems. They include both low-temperature (LT) and high-temperature (HT) ATES systems. This review also provides details on reservoir characteristics and well designs of the individual sites as well as information on the research goals and methods. Based on the comprehensive German research activities on ATES compiled in this work, lessons learned from the research findings and experiences with ATES operation and permission are highlighted.

How to cite: Menberg, K., Stemmle, R., Bauer, S., Bayer, P., Blöcher, G., Kranz, S., Felsmann, C., Hahn, F., Shao, H., Zosseder, K., and Blum, P.: Current research on Aquifer Thermal Energy Storage in Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16554, https://doi.org/10.5194/egusphere-egu24-16554, 2024.

High temperature aquifer thermal storage (HT-ATES) in hot deep aquifers is considered to optimize the usage of commonly available energy sources. This study investigates potential near-well mineralogical changes induced by HT-ATES in two different Danish geothermal reservoirs: the mineralogically mature and calcite-free Gassum Formation, and the calcite-containing Bunter Sandstone Formation.

Core flooding experiments at reservoir conditions and temperatures up to 150°C were performed with a core specimen from each of the two geothermal reservoirs and with synthetic formation water as the flooding fluid. Effluent brines for chemical analysis were collected during the experiments and mineralogical changes of the core material identified by mineralogical characterisation of the core material before and after the experiment. A 1D reactive transport model was constructed to simulate the laboratory experiment and the model was calibrated against the experimental data. This calibrated model was then extended to simulate the continuous injection for six months of heated formation water into the two sandstone reservoirs to evaluate potential near-well mineralogical and porosity changes. For the Bunter Sandstone Formation, the formation water was modified to a saturation index for calcite of -0.1 prior to injection to replicate a situation where precautions are made to avoid loss of injectivity due to calcium carbonate scaling at elevated temperatures.

For the Gassum Formation, injecting formation water up to 100°C showed no significant changes in porosity. At temperatures ≥120°C, albite and siderite contents decreased, but the impact on reservoir porosity was minimal. However, calcite precipitation near the injection well at temperatures ≥120°C may reduce injectivity. In the Bunter Sandstone Formation, the use of slightly modified formation water resulted in considerable calcite dissolution in the reservoir at all investigated temperatures and dolomitization at 150°C. Our findings indicate a potential risk of near-well clogging caused by the precipitation of dolomite at this temperature. At lower temperatures, the calcite dissolution led to increased porosity, posing a potential risk to the rock's integrity.

The study suggests that HT-ATES in reservoirs with high calcium carbonate content, like the Bunter Sandstone Formation, is challenging. Precautions to avoid calcium carbonate scaling may lead to dissolution, while neglecting precautions may cause scaling and clogging issues. In contrast, mineralogically mature and calcite-free sandstones, such as the Gassum Formation, may be suitable for excess heat storage, particularly at temperatures <100°C.

 

How to cite: Holmslykke, H. D. and Kjøller, C.: Laboratory investigations and reactive transport modelling of potential near-well mineralogical changes during seasonal heat storage (HT-ATES) in Danish geothermal reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17870, https://doi.org/10.5194/egusphere-egu24-17870, 2024.

EGU24-18502 | ECS | Orals | ERE3.6

The Reiche Zeche Geo-Lab for in-situ simulation of mine thermal energy storage (MTES): Design and insights. 

Martin Binder, Alireza Arab, Christian Engelmann, Lukas Oppelt, Chaofan Chen, Thomas Grab, Thomas Nagel, and Traugott Scheytt

The (over-)seasonal storage of excess heat and cold in the subsurface is considered a promising solution to the manifold challenges of the energy transition. Many underground thermal energy storage (TES) systems are focusing on natural aquifers. In parallel, there has also been increasing attention on using artificial cavities in (partially) flooded underground mines. This special form is known as mine thermal energy storage (MTES).

Like other underground TES systems, MTES faces several challenges. Many former mines are actively dewatered to keep a defined flooding level and, therefore, significant water flows can be present, especially in the main tunnels and shafts. The unintentional transport of stored heat energy out of the original storage area, whether through heat advection or conduction, ultimately leads to reduced recovery rates and suboptimal efficiency. Adoption of localized and hydraulically (more or less) isolated mine sections instead of entire levels may provide a solution to this technical challenge.

An MTES Geo-Lab has been recently designed and established as part of the R&D project "MineATES", funded by the German Federal Ministry of Education and Research (BMBF). The in-situ Geo-Lab is located in the former silver mine "Reiche Zeche (Himmelfahrt Fundgrube)" at the TU Bergakademie Freiberg in Saxony, Germany, and focuses on the controlled simulation of TES cycles on a manageable scale. Specifically, a cuboid-shaped experimental reservoir (water capacity of approx. 21 cubic meters) in the northern field of the Reiche Zeche’s first level, slowly flown through by acidic precipitation water (pH values between 2 and 3), was chosen. The prevalent geological formation in this area is the Freiberg gneiss. Given the pilot-scale of the study site, heat losses across system boundaries are expected to be of an experimentally manageable magnitude – and are intentionally so.

The immediate vicinity of the experimental reservoir has been equipped with an extensive thermal monitoring system. This includes more than 90 temperature sensors embedded at various distances from the reservoir walls, with some up to two meters deep and distributed across 18 boreholes. First measurements showed a background temperature in the rock of approx. 11.5°C on average. This monitoring system enables continuous tracking of transient temperature distributions in the surrounding rock, facilitating the quantification of heat losses and efficiency reductions during periodic heat/cold injection and extraction experiments, emulating real-world TES cycles. Furthermore, the Geo-Lab is equipped with multiple sampling points to monitor hydrochemical parameters over time.

How to cite: Binder, M., Arab, A., Engelmann, C., Oppelt, L., Chen, C., Grab, T., Nagel, T., and Scheytt, T.: The Reiche Zeche Geo-Lab for in-situ simulation of mine thermal energy storage (MTES): Design and insights., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18502, https://doi.org/10.5194/egusphere-egu24-18502, 2024.

EGU24-18540 | ECS | Posters on site | ERE3.6

Investigating clogging and scaling in carbonate aquifer thermal energy storage systems using batch and column experiments 

Leonie Gabler, Alireza Arab, Martin Binder, and Traugott Scheytt

Recently, Aquifer Thermal Energy Storage (ATES) systems gained increasing attention as a suitable storage method for local and temporary surplus thermal energy in aquifers. Among others, the success of ATES depends on the properties of the aquifer like hydraulic permeability, thermal conductivity, and porosity. During ATES operation, different pressure and temperature conditions above and below the surface can cause clogging and scaling processes, eventually leading to operational and maintenance issues or failures.

In the research project „UnClog-ATES“ (funded by the Federal Ministry of Education and Research of Germany - BMBF), clogging and scaling processes are investigated on an interdisciplinary basis (microbiology, geology, hydrogeology, and geochemistry) and influencing factors for carbonate aquifers are determined. Based on the findings, countermeasures (e. g. scaling inhibitors or CO2 addition) are (further) developed.

ATES conditions (pressure, temperature, hydraulics, and chemical composition) are systematically simulated: While 1-D column tests serve to model the transport processes taking place in the real system, 0-D batch reactor tests allow varying the hydrochemical environment and rock compositions. Two different ATES-relevant rocks are used as representatives of limestone in general: i) Jurassic limestone from Upper Malm, Germany ("Treuchtlinger Marmor”; mainly calcite) as a representative rock for the Malm, as well as ii) marble from Hammerunterwiesenthal, Germany (“Erzgebirgsmarmor”; calcite and dolomite). Water samples from the same Erzgebirge marble quarry are used as fluid. Batch and flow tests are conducted in cycles at ATES-typical temperatures between 5 °C and 60 °C. Quasi-continuous monitoring of fluid parameters in measuring cells and performing comprehensive hydrochemical and geochemical analyses before, during, and after the tests allows monitoring of alterations in hydrochemical and geochemical conditions. Hydrochemical analysis results of the first batch experiments (shaking “Treuchtlinger Marmor” with distilled water for approx. 30 days at 5, 40 and 55 °C) showed a decrease in the concentrations of Calcium and Magnesium with increasing temperature. Using a larger grain size showed an even greater decrease.

Accompanying the experiments, hydrochemical modeling is used to quantify the processes and to estimate the experimental parameters a priori. The simulation results with PHREEQC first showed an equilibrium of the aforementioned rock and fluid materials at 15 °C and subsequently precipitating calcite while heating stepwise. Further simulations indicate that this precipitation can be prevented by adding a certain amount of dissolved CO2.

UnClog-ATES intends to contribute to optimizing the prediction accuracy of hydrogeochemical reactions and to the creation of methods both for estimating the clogging potential and for developing and testing possible countermeasures.

How to cite: Gabler, L., Arab, A., Binder, M., and Scheytt, T.: Investigating clogging and scaling in carbonate aquifer thermal energy storage systems using batch and column experiments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18540, https://doi.org/10.5194/egusphere-egu24-18540, 2024.

EGU24-18740 | ECS | Orals | ERE3.6

Modelling the geometry of abandoned coal mines for inter-seasonal heat and cold underground storage 

Yanick N'depo, Nicolas Dupont, Thierry Martin, and Olivier Kaufmann

Wallonia (southern Belgium) experienced intense coal mining in the 19th and 20th centuries. The depths of these abandoned coal mines range from the ground surface to more than 1000 m. These abandoned mines are now being studied as potential reservoirs for inter-seasonal geothermal storage operations as part of the operation of 5th generation heating networks. In the scope of feasibility studies, a major challenge is to reconstruct the geometry of former structures and works, a preliminary but essential step in modelling flows and heat transport underground.

As these mines have long since closed and are no longer accessible, this work is based solely on archive documents such as mining maps from the former collieries and cross-sections held by the mining administration. The information available in these documents is invaluable. However, this information, some of which dates back more than a century, is sometimes difficult to interpret and cannot be considered exhaustive. Moreover, it is not homogeneous and the accuracy of the topographical information varies depending on the source and the time period.

In order to reconstruct a coherent model of the mine workings, galleries and shafts, a geological model constrained by information from archive documents is constructed. Next, the elevation of the boundaries of the mine workings and galleries in layers is adjusted on the layers derived from the geological model in order to preserve the topological links between objects. Finally, a discretised model representing the zones of increased permeability around the workings and galleries is extracted. To carry out all these operations and the associated quality controls, a workflow based on developments in Python and relying on open source libraries has been developed and tested.

How to cite: N'depo, Y., Dupont, N., Martin, T., and Kaufmann, O.: Modelling the geometry of abandoned coal mines for inter-seasonal heat and cold underground storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18740, https://doi.org/10.5194/egusphere-egu24-18740, 2024.

EGU24-19244 | Orals | ERE3.6

The realization of a high-temperature ATES in Berlin: from explorational drilling to implementation in Berlin-Adlershof 

Ben Norden, Stefan Kranz, Guido Blöcher, Simona Regenspurg, Lioba Virchow, and Ali Saadat

Concepts for achieving sustainable energy provision in urban areas require also an appropriate exploration concept for a succesful planning of a possible site-development. Geophysical exploration data and deep reaching boreholes are commonly rare in such areas. In Berlin, Germany, the German Research Centre for Geosciences drilled a research borehole to investigate the usability of Mesozoic aquifers as underground thermal storage reservoirs, the Gt BtrKoe 1/2021 borehole in Berlin-Adlershof. The information gained from this borehole provides new structural data and encounters several Mesozoic potentially ATES aquifers. The general depth of those aquifers are largely determined by the ascent and location of the underlying Permian salt structure. The research well was completely cored from a depth of 210 m (close to the top of pre-Tertiary) to the final depth of the well at 456 m. Based on an in-depth characterization of the cores that included also geophysical measurements on cores (like gamma-ray, bulk density, thermal properties, and p-XRF) and a detailed geological description, the porosity, permeability, and lithological heterogeneity of the drilled succession was evaluated and integrated in a 3D geological model. In the cored borehole section, several promising sandy reservoir sections were drilled, with a main storage reservoir in the Lower Jurassic Hettangian at a depth of 360–400 m. The sandstone is very fine grained and only weakly consolidated, showing porosities of 25–30% and permeabilities of more than 1 Darcy (> 10-12 m²). A first simulation allows for a successful integration of an ATES using this horizon at this site. The simulation is based on the seasonal provision of 35 GWh of storeable heat provided from a wood-fired combined heat and power plant  for a time period of 4 months with a temperature of 90°C, which is stored in the 24°C warm sandstone reservoir. The simulation shows that it will take about two years of operation to reach the full storage potential of the reservoir. Based on the findings, a real ATES will be established at the site, allowing to study in detail possible rock-fluid interactions and the overall performance of the system. The site activities are funded by the BMWK (FKZ 03EE4007 and FKZ 03EWR022C) and the EU project PUSH-IT (https://www.push-it-thermalstorage.eu/).

How to cite: Norden, B., Kranz, S., Blöcher, G., Regenspurg, S., Virchow, L., and Saadat, A.: The realization of a high-temperature ATES in Berlin: from explorational drilling to implementation in Berlin-Adlershof, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19244, https://doi.org/10.5194/egusphere-egu24-19244, 2024.

EGU24-19543 | ECS | Orals | ERE3.6

Revitalizing underground mines: unlocking the potential of thermal energy storage (MineATES) 

Alireza Arab, Martin Binder, Christian Engelmann, and Traugott Scheytt

Thermal Energy Storage (TES) has gained prominence as a viable solution for storing surplus heat and cold underground. While traditional TES systems primarily rely on natural aquifers, an emerging approach known as ”Mine Thermal Energy Storage“ (MTES) has garnered attention for repurposing former underground mines.

Despite the promise of TES in both Aquifer Thermal Energy Storage (ATES) and MTES, several operational challenges persist, including clogging, scaling, corrosion, and energy loss across system boundaries. These challenges impact not only the geological matrix but also the integrity of technical infrastructure components such as pipes and heat exchangers.

The “MineATES” research and development project, funded by the German Federal Ministry of Education and Research (BMBF), investigates the feasibility and limitations of employing water-filled cavities in underground mines for TES. The study primarily focuses on the ”Reiche Zeche“ silver mine, designated as a teaching and research site at the TU Bergakademie Freiberg in Freiberg, Germany. An in-situ “real-laboratory” is established there with the purpose of simulating the periodically varying heat exchange between mine water - here stored in an experimental basin and slowly flowed through with acid precipitation water (pH ~ 2 - 3) - and the surrounding Freiberg Gneiss rock. Comprehensive monitoring of hydrochemical parameters and molecular biological analyses complement multiple heating and cooling cycles within the mine.

Furthermore, laboratory-scale column flow experiments and batch reactor tests mimic TES cycles, heating columns up to 60 ⁰C and cooling them down to 10 ⁰C (Figure 1). Comparative investigations include rock materials and mine waters from two other mines in Saxony, namely a former tin ore mine in Ehrenfriedersdorf and a former hard coal mine in Lugau/Oelsnitz.

The overarching goal of all experiments is to ascertain the nature, extent, and location of potential chemical alterations during TES operations.

Figure 1-  Overview of column experiments

How to cite: Arab, A., Binder, M., Engelmann, C., and Scheytt, T.: Revitalizing underground mines: unlocking the potential of thermal energy storage (MineATES), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19543, https://doi.org/10.5194/egusphere-egu24-19543, 2024.

A series of combined laboratory scale experiments and numerical simulations of a high-temperature borehole heat exchanger (BHE) in a geological porous medium was carried out under dynamic cyclic thermal loading. The main objective of this work was to investigate the influence of the transient charging/discharging cycle time scales on thermal convection and heat transfer characteristics. The experimental unit was constructed with a vertical, grouted coaxial BHE installed in the center of a water saturated coarse sand within a 1.4 m3 cylindrical barrel. Five cyclic experiments at 70°C charging temperature and cycle durations of 6, 12 and 24 hours after a pre-charging phase, and 6 and 12 hours without pre-charging were conducted under well controlled conditions. A dense sensor grid of 129 thermocouples was deployed to record the evolution of the temperature distribution inside the unit and across the boundary. A 2D-axisymmetric numerical model of the experimental unit was developed in OpenGeoSys and validated for the coupled thermo-hydraulic processes in the porous medium by comparison to previously performed short-term static charging/discharging experiments. The model then was applied to simulate the experiments presented here. The model-to-data comparison indicated a very good agreement, and thus was further used to analyse the impact of the cyclic operation on the contribution of thermal convection to overall BHE heat transfer.

The results indicated a cumulative increase of sand temperature levels during the first cycles in the experiments without pre-charging and a decrease when cyclic operation was started after a stationary pre-charging stage, until a quasi stable behavior was reached between consecutive cycles. In general, the difference in obtained results between both operating modes for a given cycle duration was only observed within the first three to four cycles. An increase of the magnitude of convective flow characterised by increases of heat transfer rates, Rayleigh numbers, buoyant flow velocities, and temperature gradients with the cycle duration from 6, 12 to 24 hours was found. The estimated contribution of thermal convection to heat transfer at the last cycle decreased from 23% at 24 hours cycle duration to 20% and 18% at 12 and 6 hours with pre-charging, and 21% and 16 % without pre-charging, respectively. These results demonstrate that for the given experimental setup and scale, convective flow can no longer fully develop within the shorter dynamic charging cycle durations, and thus is less effective for increasing the BHE-to-sand heat transfer during heat charging.

How to cite: Djotsa Nguimeya Ngninjio, V., Beyer, C., and Bauer, S.: Impact of cyclic thermal loading on thermal convection along a high-temperature borehole heat exchanger: Laboratory-scale experimental and numerical study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20748, https://doi.org/10.5194/egusphere-egu24-20748, 2024.

EGU24-22138 | ECS | Posters on site | ERE3.6

New geomaterial for energy storage - mechanical and thermal properties  

Konrad Kołodziej, Marcin Lutyński, and Piotr Pierzyna

The development of renewable energy sources requires the development of technologies and further expansion of energy storage infrastructure on global markets. One type of energy storage is thermal energy storage(TES). Ongoing researches aim at improving the efficiency of storage and heat transfer in such installations. An important element of these installations is the reservoir that accumulates thermal energy. The following work presents research on new geomaterials based on waste materials, mining raw materials and mixed materials based on them, which could potentially be used as materials for the construction of a packed bed or resevoir that stores thermal energy in TES. These materials, due to the possibility of forming almost any shapes, should exceed the efficiency of aggregate minerals. Additionally, their utilization can partially or fully eliminate mining waste, thereby promoting circular economy principles. 

How to cite: Kołodziej, K., Lutyński, M., and Pierzyna, P.: New geomaterial for energy storage - mechanical and thermal properties , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22138, https://doi.org/10.5194/egusphere-egu24-22138, 2024.

EGU24-1143 | ECS | Posters on site | ERE3.7

Exploring Carbon Sequestration through Mineral Carbonation in Serpentinite Mud Volcanoes 

Mafalda Freitas, Sonja Geilert, Alexander Heuser, Klaus Wallmann, and Vitor Hugo Magalhães

Mineral carbonation is a sequence of natural processes that can be summarized as a net reaction of carbon dioxide (CO2) with metal-bearing minerals, producing stable carbonates. The rapid increase in anthropogenic CO2 emissions has created an imbalance in the carbon cycle which natural mineral carbonation is not able to offset by itself. The severity of the problem now requires the use of an array of carbon sequestration techniques, such as Carbon Dioxide Capture and Storage (CCS) and Carbon Dioxide Removal (CDR) in addition to drastically reduced greenhouse gas emissions. Mineral carbonation has been drawing attention as a potentially sustainable technology to reach carbon neutrality, by storing CO2 as carbonate minerals that are stable over a long period of time. Thus, many recent studies have focused on characterizing the chemical reactions that occur during mineral carbonation and developing methods to improve its efficiency, however, mostly under laboratory conditions.

The Mariana forearc presents a unique opportunity to study these processes in a natural system, as mineral carbonation occurs as authigenic carbonate precipitates in the serpentinized muds from large mud volcanoes. We analysed samples collected from three serpentinite mud volcanoes – Yinazao, Asùt Tesoru and Fantangisña – during the IODP 366 expedition to characterize the C, O and Ca isotopic composition of these authigenic carbonates. They consist of rhombohedral calcite and aragonite needles and spherulites found predominantly in the core’s top meters. At Yinazao aragonite occurs in the mud volcano’s summit, showing a δ13C of ~0±0.9‰, δ44/40Ca of ~0±0.5‰, and δ18O ~5±0.3‰, while calcite is found on the mud volcano’s flank, with higher values of δ13C and δ44/40Ca (~2.9±0.08‰ and 1.4±0.06‰, respectively), and lighter δ18O (~1.7±0.43‰). As for Asùt Tesoru and Fantangisña we also found aragonite needles and spherulites on the mud volcanoes’ flank and summit, respectively, with similar δ13C, δ44/40Ca and δ18O isotopic signatures compared to the ones from Yinazao.

These results emphasise the importance of these mud volcanoes as ideal models to study mineral carbonation reactions in a naturally occurring system. Importantly, they show that seawater is the major source of carbon for the authigenic carbonate precipitation. This precipitation is the result of the reaction between seawater with the highly alkaline fluids sourced by serpentinization reactions that ascend through the mud volcanoes.

This knowledge highlights the importance of mineral carbonation as a potentially effective approach for both CDR and CCS, as well as the need for further studies in natural systems. Additionally, it shows that understanding how mineral carbonation occurs naturally may be the key to overcoming many of the challenges we currently face when developing efficient carbon sequestration technologies.

How to cite: Freitas, M., Geilert, S., Heuser, A., Wallmann, K., and Magalhães, V. H.: Exploring Carbon Sequestration through Mineral Carbonation in Serpentinite Mud Volcanoes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1143, https://doi.org/10.5194/egusphere-egu24-1143, 2024.

EGU24-2945 | ECS | Posters on site | ERE3.7

A microfluidic approach to understanding coupled dissolution-precipitation during CO2 storage in fractured systems 

Haylea Nisbet, Michael Chen, Chelsea Neil, and Hari Viswanathan

Until recently, efforts to understand the fluid dynamics processes occurring in flowing fractures have generally excluded chemical reactions or only explored one reaction: dissolution or precipitation. This has hindered our progress in predicting the CO2 storage potential in a given system because it has limited our understanding of in situ carbon mineralization. Identifying the influence of fluid flow in fractures on geochemical reactions is particularly important for CO2 mineralization in low-permeability rocks, such as ultramafic rocks (e.g. peridotite), which will rely on fractures to act as primary conduits for CO2 distribution and mineralization. We are working towards bridging this knowledge gap by conducting experiments using an advanced high-P, high-T microfluidics setup that permits real-time visualization of carbon mineralization in a coupled dissolution-precipitation regime under flowing conditions.

In order to understand fundamental regimes of coupled dissolution and precipitation relevant to mineral carbonation, experiments have been conducted in an analog setup where the dissolution of gypsum (CaSO4) by a carbonate solution is coupled to the precipitation of calcite (CaCO3). The fracture model used in the experiments included a primary channel and dead ends, which define advection and diffusion-dominated zones. We conducted experiments under different flow conditions, and the results revealed key factors that affect optimal carbonation. The amount, morphology, and geochemistry of carbonate mineralized was strongly influenced by the fluid flow rate. These results suggest that the rate of CO2 injection could be an important parameter to consider during in situ carbon mineralization operations.

How to cite: Nisbet, H., Chen, M., Neil, C., and Viswanathan, H.: A microfluidic approach to understanding coupled dissolution-precipitation during CO2 storage in fractured systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2945, https://doi.org/10.5194/egusphere-egu24-2945, 2024.

EGU24-3234 | ECS | Posters on site | ERE3.7

Low-frequency shadow (LFS) as a tool for CO2 sequestration of Sleipner field North Sea 

Emmanuel Anthony and Thomas Bohlen

Seismic low-frequency shadow (LFS) is a zone in the seismic data that is characterized by strong anomalously low-frequency energy compared to its surroundings and it occurs beneath a body that strongly attenuates the energy of the propagating seismic waves. LFS can be used as a tool to monitor the migration of CO2 in a reservoir. To demonstrate this on the Sleipner field, North Sea, where a large amount of CO2 is being sequestered in the deep saline Utsira Formation. A spectral decomposition analysis of time-lapse 3D seismic data of the Sleipner field, North Sea, was carried out using the continuous wavelet transform. We examined the common frequency stacks corresponding to frequencies 10 Hz, 14 Hz, 30 Hz, and 40 Hz for the occurrence of LFS in the pre-and post-CO2 injection cases data. We did not find any signatures corresponding to LFS in the pre-CO2 injection
scenario. In the post-CO2 injection cases, LFSs were detected below the reservoir base at frequencies lower than 30 Hz. It is shown that the seismic low-frequency shadows are not artefacts but occur due to attenuation of the high-frequency components of the propagating seismic waves in the CO2-saturated Utsira Formation. The low-frequency shadows are localized anomalies at the base of the formation; hence it can be applied to study the behaviour of CO2 when stored in a reservoir.

How to cite: Anthony, E. and Bohlen, T.: Low-frequency shadow (LFS) as a tool for CO2 sequestration of Sleipner field North Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3234, https://doi.org/10.5194/egusphere-egu24-3234, 2024.

EGU24-3927 | ECS | Posters on site | ERE3.7

From numerical expectations to experimental observations: Unraveling the complexities in CO2-basalt interactions and mineral growth in porous media 

Mohammad Nooraiepour, Mohammad Masoudi, Beyene Girma Haile, and Helge Hellevang

Subsurface fluid flow and solute transport are pivotal in addressing pressing energy, environmental, and societal challenges, such as the geological storage of carbon dioxide (CO2). Basaltic rocks have emerged as highly suitable geological substrates for injecting large volumes of CO2 with emission reduction and carbon mineralization purposes. This preference is attributed to their widespread occurrence at Earth's surface, high concentrations of cation-rich silicate minerals, reported fast mineralization rate, and often favorable characteristics such as porosity, permeability, and injectivity. The mineralization process within basaltic rocks is intricately linked, involving the dissolution of silicate minerals and the subsequent precipitation of carbonate minerals. During this chemical interplay, silicates play a crucial role by contributing vital calcium (Ca), magnesium (Mg), and iron (Fe) ions essential for the precipitation of carbonate minerals, including Ca-, Mg-, and Fe-carbonates. Understanding the consequences of mineral nucleation and growth in porous media and the fate of subsurface flow and transport necessitates spatial and temporal knowledge of solid precipitation locations and amounts. Only then can the reactive transport models provide precise and realistic predictions on the intricate interplay between transport mechanisms and reaction kinetics and, therefore, advection-diffusion-reaction (ADR). However, accurately representing the dynamics and dimensionality of mineral nucleation and growth in porous media is still challenging. There is a continued need for theoretical development to precisely predict the occurrences where ADR coupling occurs in the space and time domains. We conducted an integrated investigation involving experimental and numerical approaches to gain deeper insights into the spatial distribution of secondary mineral growth. Laboratory experiments under static (batch reactors) and dynamic (columnar flow cells) conditions at elevated pressure and temperature explored variations in aqueous solutes, pH, thermodynamic conditions, and residence time. Despite numerical predictions suggesting the formation of MgFeCa-carbonates in CO2-basalt interactions at higher temperatures, our laboratory findings primarily indicated the growth of calcium carbonates, namely calcite and aragonite. The lack of MgFeCa-carbonates, such as ankerite, siderite, and magnesite, remains elusive but is presumed to be associated with the concurrent occurrence of clay fractions, particularly smectites, consistently observed in batch-type experiments. Columnar flow experiments revealed the spontaneous formation of a limited number of large crystals at various locations, rationalized by the overarching influence of probabilistic mineral nucleation. This underscores the need for a new probabilistic approach to accurately model kinetics and crystal growth distribution in numerical simulations, where dynamic ADR may steer geochemical reactions towards favorable or unfavorable regions in terms of carbon mineralization efficiency.

How to cite: Nooraiepour, M., Masoudi, M., Haile, B. G., and Hellevang, H.: From numerical expectations to experimental observations: Unraveling the complexities in CO2-basalt interactions and mineral growth in porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3927, https://doi.org/10.5194/egusphere-egu24-3927, 2024.

EGU24-4303 | Orals | ERE3.7

Reaction-induced fracturing during serpentinite carbonation promoted by selective dissolution of brucite 

Masaoki Uno, Taiki Igarashi, and Atsushi Okamoto

Although ultramafic rocks have a high potential for mineral carbonation, their low porosity and thereby slow reaction kinetics remain challenges for artificial mineral carbonation of ultramafic rocks. Field observations suggest that carbonation of ultramafic rocks proceeds with reaction-induced fracturing, caused by the solid volume increase during carbonation[e.g., 1,2]. However, such reaction-induced fracturing has not been clearly reproduced in laboratory settings for carbonation. Here we show a clear experimental example of macroscopic reaction-induced fracturing caused by carbonation of brucite-bearing serpentinite.

Cylindrical cores (6 mm in diameter and 5 mm in height) of fine-grained brucite-bearing serpentinite were reacted with 1M NaHCO3 solution or CO2-saturated water at 90–200°C during batch experiments for one week. Clear macroscopic fractures were observed for samples reacted with NaHCO3 solution at 150 and 200°C. These samples were fractured by two types of tensile fractures: (a) diagonal fractures that cut the inside of the cylindrical samples, and (b) regularly spaced, vertical short fractures on the sample surface. Diagonal fractures are partly filled with magnesite and are cut by surficial vertical fractures. Reaction front is characterized by formation of porous serpentine that surround the original serpentine-brucite mixture. Magnesite-serpentine mixture further surrounds the porous serpentine, forming mesh texture-like magnesite-serpentine networks.

Above observations suggest that selective dissolution of brucite at the reaction front increase the Mg concentration and pH in the local solution, leaving porous serpentine. Magnesite preferentially precipitates at pre-existing micro cracks, causing local volume increase. These reaction and volume increase exert tensile stress inside the sample, causing macroscopic diagonal fractures. The diagonal fractures promote fluid transport and reaction within the inner part of the sample. The volume increase inside the sample induces tensional stress on the surface of the sample, causing surficial vertical fractures, which further enhance carbonation reactions.

We propose selective dissolution of brucite and preferential magnesite precipitation at pre-existing micro cracks induce macroscopic fracturing, create fluid flow paths and new reactive surface area, and accelerate carbonation of massive serpentinite. Such heterogeneous distribution of minerals with contrasting reactivity would be important for self-enhanced mineral carbonation.

 

1 Kelemen et al., 2011 Annual Review of Earth and Planetary Sciences, 39, 545–576.

2 Uno et al., 2022 Proceedings of the National Academy of Sciences, 119, e2110776118.

How to cite: Uno, M., Igarashi, T., and Okamoto, A.: Reaction-induced fracturing during serpentinite carbonation promoted by selective dissolution of brucite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4303, https://doi.org/10.5194/egusphere-egu24-4303, 2024.

EGU24-8820 | ECS | Orals | ERE3.7

Numerical fluid flow modelling in the context of CO2 sequestration on mid-ocean ridge flanks 

Isabel Kremin, Lars Rüpke, Isabel Lange, Wolfgang Bach, and Zhikui Guo

The majority of Earth’s basaltic volcanism occurs at mid-ocean ridges, where new ocean floor is created. Especially young oceanic crust, which is highly porous and permeable, is subject to regional off-axis hydrothermal circulation, which extracts large amounts of heat and impacts global water and chemical fluxes between the ocean and the lithosphere. Generally, seawater recharge and hydrothermal fluid discharge happen where the basaltic crust is exposed to the seafloor. This mode of circulation is usually referred to as outcrop-to-outcrop flow. Basaltic aquifers, overlain by impermeable sedimentary layers, can sustain outcrop-to-outcrop flow over distances of several 10s of kilometers. Basaltic rock formations are also explored for their potential to store injected CO2 with the added benefit that carbonation reactions promote the safe long-term storage. In this context, it is uncertain  whether natural hydrothermal flow between outcropping seamounts compromises a long-term storage or whether it will help to continuously expose injected CO2 to fresh reactive basaltic rock.

Numerical fluid flow modelling on different scales is a powerful tool to understand the relations between off-axis hydrothermal circulation and CO2 storage. On the one hand, coupled heat transfer and fluid flow modelling of regional ridge flank flow can be performed at the kilometer scale and compared with heat flow observations. By using such regional models, we find that outcrop-to-outcrop flow arises if the permeability of the basaltic aquifer is larger 10-13 m2. This regional crustal permeability primarily controls the flow velocity and discharge mass fluxes. In the presence of outcrop-to-outcrop flow, the permeability and geometric shape of the outcrops further determine the direction of the flow. Secondly, the flow rates and fluid temperatures in the aquifer are influenced by the thickness of the sediment and the distance between the outcrops, respectively. These results based on regional models help to constrain flow patterns through the basaltic crust from seafloor observations, e. g. heat flow measurements in the sediment. Understanding these regional flow patterns is a compelling necessity in the context of COsequestration on mid-ocean ridge flanks.

On the other hand, in-situ carbon mineralization in porous basaltic crust can modify crustal permeabilities on local and regional scales, and thus influence regional circulation patterns. In this regard, we use pore scale numerical fluid flow simulations based on core samples in combination with laboratory experiments to parameterize the permeability evolution during carbonization reactions. Results of pore-scale modelling can be incorporated into the regional flow models to further enhance understanding of the interplay between off-axis hydrothermal circulation and carbon sequestration in mid-ocean ridge basalts.

How to cite: Kremin, I., Rüpke, L., Lange, I., Bach, W., and Guo, Z.: Numerical fluid flow modelling in the context of CO2 sequestration on mid-ocean ridge flanks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8820, https://doi.org/10.5194/egusphere-egu24-8820, 2024.

EGU24-9786 | Posters on site | ERE3.7

Natural carbon sequestration process into shallow sill intrusions – numerical modelling, land-based and IODP drilling investigations 

Christophe Galerne, Hasenclever Jörg, Alban Cheviet, Woflgang Bach, Nils Lenhardt, Junli Zhang, Christin wiggers, Wolf-Achim Kahl, Achim Kopf, Martine Buatier, and Annette Götz

Permanent carbonate mineralisation in basalt is a promising solution for Carbon Capture and Storage of anthropogenic greenhouse gases without the risk of leakage. While this process is known to occur at relatively low temperatures below 100°C, new research on Large Igneous Provinces (LIPs) and young rift basins suggests that much of the thermogenic gases mobilised during contact metamorphism can remain trapped and mineralised in the sills that mobilised them. This discovery is the result of two distinct drilling investigations on land (KARIN) and at sea (IODP Exp 385). It shows that basalts may not only trigger the sudden release of thermogenic gas, but also represent an important carbon sink. The two examples of carbonate trapping in sills presented here are from the Karoo and Guaymas basins. Results indicate that a large fraction of epimagmatic fluids charged with thermogenic gas systematically penetrated inside the sills during cooling. Our numerical solutions suggest that in both cases the higher permeability of the sill acquired during cooling and crystallisation compared to that of its host, ultimately dictates the fate of the thermogenic gas that accumulated in the igneous bodies.

How to cite: Galerne, C., Jörg, H., Cheviet, A., Bach, W., Lenhardt, N., Zhang, J., wiggers, C., Kahl, W.-A., Kopf, A., Buatier, M., and Götz, A.: Natural carbon sequestration process into shallow sill intrusions – numerical modelling, land-based and IODP drilling investigations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9786, https://doi.org/10.5194/egusphere-egu24-9786, 2024.

EGU24-10093 | ECS | Posters virtual | ERE3.7

Serpentinized ultramafic rocks of Evia Island (Greece) as potential reservoirs for CO2 mineralization based on a petrological research 

Christos Karkalis, Andreas Magganas, Nikolaos Koukouzas, and Petros Koutsovitis

In the island of Evia (Aegean, Greece), big peridotitic masses crop out in the central and north parts displaying different extents of serpentinization. These rocks were frequently subjected to CO2-metasomatism [1,2] forming magnesite deposits that have been exploited for several years for industrial purposes (currently by Grecian Magnesite and TERNA Mag companies). The non-carbonated ultramafic rock types mostly appear in the broader areas of Pagondas, Dafni, Psachna, Makrimalli, Artaki and Vatondas. These are predominantly divided into serpentinized harzburgites/lherzolites and serpentinites, whereas scarce occurrences of garnet-bearing serpentinites are rarely evident close to the Pagondas locality in spatial association with rodingites [3]. The mineralogy [mostly serpentine ± (clino- and ortho-) pyroxenes ± olivine ± garnet] and geochemistry (i.e. high MgO, FeO and occasionally CaO contents) of representative rock samples from the Pagondas and Psachna-Makrimalli regions indicate that they can react with carbonated water in order to crystallize carbonate mineral phases. This is also shown by thermodynamic calculations with PERPLE_X software [4], which simulate the natural carbonation of Central Evia ultramafic rocks, revealing that they have the physicochemical potential to form specific carbonate minerals (siderite, magnesite and calcite) at T ≤ ~390oC. Thus, it is concluded that in Central Evia the petrological properties and relatively high quantities of serpentinized peridotites, offer a potentially viable option for their exploitation as reservoir rocks during in-situ CO2-storage. These non-carbonated ultramafic outcrops are located proximal to: (a) the Western and Eastern coastline of Evia Island (i.e. ~6 km far from the Evoikos Gulf and ~20 km far from the Aegean Sea), (b) the Central Evia groundwaters [5],  (c) the Edipsos hot-springs in Northern Evia [6] and (d) areas with industrial activities close to the city of Chalkida. Hence, their geographical distribution could contribute to the financial viability of such storage scenarios lowering the logistic costs and contributing to sustainable development through actions for the mitigation of climate change.

References: [1] Karkalis, C. 2022: PhD-Thesis National and Kapodistrian University of Athens, Department of Mineralogy and Petrology, 371p; [2] Grieco et al., 2023: Minerals, 13(2), 159; [3] Karkalis et al., 2022: Lithosphere, 2022 (1): 9507697; [4] Connolly, J.A.D., 2009: Geochem Geophys 10, Q10014; [5] Voutsis et al., 2015: J. Geochem. Explor., 159, 79-92; [6] Kanellopoulos et al., 2016:  Proc. 14th Intern. Congress Geol. Soc. Greece, Thessaloniki, May 2016, 50(2), 720-729

How to cite: Karkalis, C., Magganas, A., Koukouzas, N., and Koutsovitis, P.: Serpentinized ultramafic rocks of Evia Island (Greece) as potential reservoirs for CO2 mineralization based on a petrological research, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10093, https://doi.org/10.5194/egusphere-egu24-10093, 2024.

EGU24-11564 | ECS | Orals | ERE3.7

Unraveling Heterogeneous Fluid Pathways in Basaltic Lava Flow Facies: Implications for subsurface CO2 Storage 

Antoine Auzemery, Cédric Bailly, Pallares Carlos, Fadi Nader, and Julien Schmitz

Unlocking the Potential of Subsurface Geological Formations for Sustainable Energy and CO2 Storage necessitates a nuanced understanding of fluid dynamics, notably within diverse volcanic facies. Addressing pivotal challenges entails delving deeper into reactive flow physics and minimizing uncertainties in geological assumptions, particularly pertaining to top seals and vertical reservoir barriers. This study examines the complexities of fluid flow within reactive volcanic porous media, specifically focusing on fractured lava sequences, presenting a promising avenue for future energy storage strategies. Stemming from a comprehensive field study in the Faroe Islands, our research seeks to unravel the reservoir architecture and fluid pathways within fractured lava sequences, with a specific emphasis on two distinct basaltic lava flow facies: the Compound and Tabular lava flows.

Leveraging techniques such as drone-based photogrammetry, geological surveys, geochemical and petrophysical data, we seek to construct 3D synthetic reservoir models of these contrasting volcanic facies. The Compound facies at Vidoy showcases lobe-like structures formed from ancient fluid lava tunnels, favoring subsequent fracturing in an alveolar network. In contrast, the Tabular facies at Suduroy, characterized by massive (10m thick) layers, exhibits contrasting microlithic cores with limited porosity and highly porous tops, featuring corded facies networks. This diverse cooling structure engenders partitioned permeability pathways, with predominantly vertical fracturing across the lava flow and horizontal networks at its porous tops.

These findings yield crucial insights into the heterogeneous nature of fluid pathways within distinct volcanic facies, establishing the groundwork for refining models crucial for sustainable energy storage strategies. Addressing challenges tied to limited subsurface data and geophysical resolution underscores the need for refined methodologies in evaluating volcanic reservoir properties. This research significantly contributes to upscaling properties in basaltic porous formations, deepening our understanding of their potential as reservoirs or seals for sustainable energy storage solutions.

How to cite: Auzemery, A., Bailly, C., Carlos, P., Nader, F., and Schmitz, J.: Unraveling Heterogeneous Fluid Pathways in Basaltic Lava Flow Facies: Implications for subsurface CO2 Storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11564, https://doi.org/10.5194/egusphere-egu24-11564, 2024.

EGU24-11861 | ECS | Posters on site | ERE3.7

Large scale molecular modelling of basalt surfaces and fracturing in basaltic glass 

Marthe Grønlie Guren, Henrik Andersen Sveinsson, Razvan Caracas, Anders Malthe-Sørenssen, and Francois Renard

How fracture initiate and propagate at the nanoscale controls the specific surface area available for fluid-rock interactions. Fracturing creates surface area and flow pathways, which control the flow mixing properties and reactivity. However, how fractures form at the nanoscale in basaltic glasses remains enigmatic. Here, we implement molecular dynamics simulations to reproduce fracture propagation in amorphous basalt. These simulations require large systems and long simulation times and are therefore currently depending on interatomic potentials rather than ab initio calculations. We have developed a machine-learned interatomic potential for basaltic glass that allow using molecular dynamics simulations to simulate fracture propagation at the nanoscale. This interatomic potential reproduces the mechanical properties of bulk solid and molten basalt over a wide range of temperatures and pressures. During a molecular dynamics simulation, bonds are formed and broken as the atoms and ions move. As a result, various species may form and migrate into the glass or towards the surface. In order to study how a basalt surface changes over time we looked at the cation-anion species on the surface and measured how long each species lived on the surface before the coordination changes. Our results show that the process zone around propagating cracks in basaltic glasses at the nanoscale is much larger than for instance when quartz breaks, and that cavities open ahead of the crack tip, and grow with time until they coalesce. A similar propagation process has been observed in fracture experiments on silica glasses at nanometer scale using atomic force microscopy and is reminiscent of the ductile fracturing process observed in metals. By training the interatomic potentials with water and carbon dioxide as fluids, we also aim to study how dynamic fractures may damage a basaltic glass and how the water and carbon dioxide enter these fractures in the wake of rupture. These simulations are relevant for carbon mineralization where a coupling between dissolution of the basalt and precipitation of carbonate minerals may lead to nanoscale fracturing of the rock.

How to cite: Guren, M. G., Sveinsson, H. A., Caracas, R., Malthe-Sørenssen, A., and Renard, F.: Large scale molecular modelling of basalt surfaces and fracturing in basaltic glass, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11861, https://doi.org/10.5194/egusphere-egu24-11861, 2024.

EGU24-12028 | ECS | Posters on site | ERE3.7

The Quantification of Ultramafic Mine Waste Reactivity for Carbon Mineralization 

Xueya Lu and Gregory Dipple

The urgent need for net-negative greenhouse gas emissions in the face of climate change is driving the global energy transition. Essential to this transition is the growing demand for critical metals, which leads to the need for more sustainable mining activities. Carbon mineralization via ultramafic-type minerals and tailings is one of the many strategies that can effectively reduce the carbon footprint associated with mining. The process involves the liberation of cations through dissolution and the subsequent precipitation of carbonate minerals to capture and store CO2 permanently. In this context, the rate and capacity of cation liberation are crucial, dictating the suitability of ultramafic mine wastes for carbon sequestration.

Our earlier research focused on the characterization of 'labile cations,' derived from transient, early-stage dissolutions, which signify a critical aspect of the reactivity and carbon capture potential of ultramafic tailings. Labile cations, predominantly governed by mineral content, are essential for rapid and cost-effective carbon capture using these tailings. Despite recognizing the concept of labile cations, understanding the sources and controls of labile Mg in ultramafic minerals, rocks, and tailings remains limited. Moreover, there is a pressing need for the development of efficient, user-friendly, and cost-effective experimental, numerical, and technical tools. Addressing this, our study employs batch dissolution experiments and data science techniques, including Multiple Linear Regression (MLR) and Principal Component Analysis (PCA), to assess carbon mineralization reactivity. We report on the extraction of labile Mg from various sources such as serpentine, hydrotalcite group minerals, serpentinite, and ultramafic tailings, examining the impact of factors like grain size, ore heterogeneity, and brucite content.

Mineral content is a primary control on labile Mg content. Interestingly, labile Mg content is quite variable within mineral groups. For instance, within the serpentine group, chrysotile and lizardite contribute notably higher Mg than antigorite. Likewise, the reactivity of hydrotalcite minerals is influenced more by the nature of their divalent and trivalent cations rather than by anion species. We also find that the original rock composition and mineral alteration progression are crucial in determining brucite abundance, serpentine type, and labile Mg accessibility. MLR and PCA analysis highlights the critical role of mineralogy and reactive surface area in predicting carbon mineralization reactivity. Overall, the results from this study offer significant advancements in the assessment of carbon mineralization potential in ultramafic mine wastes. These insights are instrumental in refining both ex-situ and in-situ carbonation strategies and extend their applicability to a broader range of alkaline solid wastes for CO2 capture and storage.

How to cite: Lu, X. and Dipple, G.: The Quantification of Ultramafic Mine Waste Reactivity for Carbon Mineralization, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12028, https://doi.org/10.5194/egusphere-egu24-12028, 2024.

EGU24-12383 | Orals | ERE3.7

Characterizing lava flows in offshore North Atlantic boreholes: a review with implications for basalt carbon storage 

John Millett, Sverre Planke, David Jolley, Christian Berndt, Peter Betlem, Marija Rosenqvist, Dmitrii Zastrozhnov, Simona Pierdominici, and Reidun Myklebust

Widespread and large-scale volcanism associated with the North Atlantic Igneous Province (NAIP) erupted during the Paleocene and Early Eocene and covers vast regions of the conjugate North Atlantic rifted margins. The majority of the preserved volume occurs in the offshore sequences of the continental shelves of Greenland, the Faroe Islands, UK, and Norway. These vast mafic igneous rock volumes in the offshore NAIP have been proposed as a potential area for permanent CO2 storage. However, a wide range of factors influence the suitability of mafic rock masses to act as fluid reservoirs including perhaps most importantly the volcanic facies (and associated pore structure, permeability, and distribution), along with alteration state, fracturing, and reactivity. In this contribution we focus on assessing the nature, distribution, and reservoir potential of sub-aerial lava flows from available borehole data across the NAIP. Lava flows are chosen for focus as they represent the most favorable reservoir target identified to date whilst also often constituting the dominant facies within much of the accessible NAIP offshore sequences.

Over 50 offshore boreholes have penetrated the lava sequences of the NAIP including both industry and scientific boreholes drilled from the 1970’s onwards. Boreholes have encountered anything from a single lava flow through to several 10’s of lava flows in volcanic sequences reaching over 2 km in cumulative thickness in the deepest industry wells such as Brugdan (6104/21-1) and Lagavulin (217/15-1z) in the Faroese and UK sectors respectively.

A summary of the lava flow nature (simple, compound, thickness, core-crust ratios) and physical property ranges (P-wave velocity, density, resistivity) of the penetrated lava flow sequences is presented utilizing available core, sidewall core, wireline and drill cuttings data to support the facies appraisal.

Borehole data and the level of possible interpretation vary significantly depending on the age, purpose, and importantly the drilling operations of the individual boreholes. Some of the most robust and complete datasets are represented by modern hydrocarbon industry boreholes, for example those from the Rosebank Field in the UK sector, and cored boreholes from recent IODP Expedition 396 drilling Mid-Norway. Results from Expedition 396 are presented to highlight formation evaluation approaches for NAIP lava flow sequences including assessing the effects of different lava flow facies on Net to Gross calculations and the impact of alteration and secondary alteration on wireline log responses.

This study presents important new constraints on the nature, variability, and distribution of NAIP lava flows from extensive available borehole ground truth data forming a foundational study for the development of reservoir appraisal techniques in the province going forward.

How to cite: Millett, J., Planke, S., Jolley, D., Berndt, C., Betlem, P., Rosenqvist, M., Zastrozhnov, D., Pierdominici, S., and Myklebust, R.: Characterizing lava flows in offshore North Atlantic boreholes: a review with implications for basalt carbon storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12383, https://doi.org/10.5194/egusphere-egu24-12383, 2024.

EGU24-12878 | ECS | Orals | ERE3.7

Feasibility of in-situ carbon mineralization in serpentinite via shallow injection, British Columbia, Canada 

Katrin Steinthorsdottir, Greg Dipple, Sandra Snæbjörnsdóttir, Mana Rahimi, Shandin Pete, Christa Pellett, Brady Clift, and Salka Kolbeinsdóttir

Carbon storage via shallow CO2 injection and mineralization in subsurface geologic formations has been demonstrated at the kilotonne scale in basalt (e.g., Hellisheidi, Iceland) but not in ultramafic rock. This type of storage dissolves CO2 in water that is then injected underground into shallow rock formations from 300-2000 m depth, where it reacts and forms permanent carbonate minerals. This project assesses the potential for CO2 injection into serpentinite, specifically within British Columbia, Canada.

Site selection included multi-criteria index overlay analysis for logistical factors (e.g. water, electricity, access) and evaluation of geological data to prioritize which sites contain 1 km2 mapped voluminous serpentinite. Of the 746 mapped ultramafic formations, 84 formations within 21 areas meet threshold criteria, and of these, three stand out with clearly higher potential. These are 1) the Shulaps complex, 2) the Coquihalla serpentine belt, and 3) the Tulameen intrusion, all in southwest British Columbia. These areas have in common that they are close to infrastructure, are located in regions with higher annual temperatures, and have known geological and geophysical characteristics indicative of serpentinite. The Shulaps and Coquihalla are mantle massifs and mainly composed of serpentinized harzburgite, and Tulameen is an Alaskan-type ultramafic intrusion with a serpentinized dunite core.

Six different carbon storage potential estimates using volume limitations, dissolution, and reactivity rates from experiments, and natural analogues are shown for the three potential sites, for Shulaps 141.2-18,682 MtCO2, for Coquihalla 9.416-1,245 MtCO2, and for Tulameen 2.825-373.6 MtCO2. Fieldwork observations and preliminary results show, as expected, heterogeneity of protoliths, serpentinization extent, and fracture density between the areas. Coquihalla was selected for a proposed pilot injection study because of its high serpentinization extent (>90%, suggesting high reactivity), continuous high fracture density (suggesting adequate injectivity), site accessibility through existing road systems, and proximity to electricity.

An additional aspect of project development is engagement with local communities. All three of the top-ranked sites fall within traditional lands of First Nations peoples, and we conducted early engagement with 22 First Nations or alliances. The priorities for engagement were to inform people about the project and its implications, get consent for fieldwork, have a discussion, and start relationship building.

How to cite: Steinthorsdottir, K., Dipple, G., Snæbjörnsdóttir, S., Rahimi, M., Pete, S., Pellett, C., Clift, B., and Kolbeinsdóttir, S.: Feasibility of in-situ carbon mineralization in serpentinite via shallow injection, British Columbia, Canada, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12878, https://doi.org/10.5194/egusphere-egu24-12878, 2024.

To meet temperature goals that limit warming to well below 2°C requires the removal of hundreds of billions of tonnes of CO2 from the atmosphere over the course of this century. Effective Carbon Dioxide Removal (CDR) methodologies will be required to reduce net emissions in the near term, counterbalance residual CO2emissions to achieve net-zero in the medium term, and contribute to net-negative emissions in the longer term– all of this in a sustainable and safe manner.

The AIMS3 project (www.aims3.cdrmare.de) will deliver new insights, monitoring tools and feasibility assessments for CO2 storage at oceanic Carbon Capture and Storage (CCS) sites, specifically in basalticrocks of the oceanic crust. The study forms a distinct progression of CO2 injection experiments carried out before (Sleipner gas release experiment, EU STEMM-CCS project, etc.) in former coastal subseafloor reservoirs or saline aquifers. Instead, AIMS3 focuses on the flanks of mid-ocean ridges where porous basaltic crust is overlain by thin sediment successions of low permeability as a cap. These basalts react quickly with injected CO2 (dissolved, liquid, or supercritical), which is fixed effectively in carbonate minerals without the risk of a later escape, ideally in deep water environments. Inflow of cold seawater and discharge of warmed hydrothermal fluids are focused and directed at such sites and help dispersing CO2 into wider areas, hence requiring fewer injection sites in case of future storage activities.

The talk will present ongoing work at the Reykjanes Ridge south of Iceland. Together with industrial partners, AIMS3 is currently setting up a ridge flank observatory with a transect of boreholes through the fill of young sediment ponds into the upper oceanic crust. The boreholes are equipped with observatories, which will include a suite of cost-effective sensors, landers and robots to identify and quantify CO2 with high precision and accuracy. Here we outline the rationale of AIMS3, provide an overview of the activities, and highlight some of the expedition results, with the goal to stimulate communication and collaboration.

How to cite: Kopf, A. and the AIMS3 research team: Technology Development, Field Assessments and Modelling Efforts for Sub-Seabed Basalt Storage of Carbon Dioxide on the Reykjanes  Ridge, Mid-Atlantic Ocean, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14732, https://doi.org/10.5194/egusphere-egu24-14732, 2024.

EGU24-16577 | Orals | ERE3.7

Geochemical characterization of the Coda Terminal CO2 storage site, Iceland 

Martin Voigt and Iwona Galeczka

The Carbfix methodology has been demonstrated to be a safe and cost-effective approach to reduce the carbon dioxide (CO2) emission into the atmosphere. The 2012 pilot study proved that 95% of the CO2 that was initially injected mineralized mainly as calcium carbonate in the shallow reservoir at 20-50 °C in less than two years. Followed by its successful outcome, the Carbfix methodology has been a foundation for many scaled-up CO2 mineralization projects, e.g., the Coda Terminal, a cross-border carbon transport and storage hub in Iceland. The value chain of CO2 includes: 1) capturing at industrial sites in Europe, 2) shipping to the Terminal in Iceland, 3) offloading and conditioning, 4) injection through a network of wells into the basaltic bedrock for subsequent 5) subsurface mineral storage. The Coda Terminal injections will be scaled-up stepwise, with a full annual injection capacity of 3 MtCO2.

Several wells of varying depth have been drilled to explore and characterize the subsurface at the Coda Terminal storage site. The water collected from these wells show variable composition depending on their depth and location. Currently, the water from the main feed zone close to shore is saline with a conductivity of about 40000 μS/cm and a pH of about 8.4. In contrast, a well further away from shore shows low conductivity of about 100 μS/cm and is relatively alkaline (pH of 10.9). Shallow water supply wells are tapping the uppermost part of the Coda groundwater body with a conductivity of 100 μS/cm and a pH of about 9.0. The CO2 concentration in these wells is within the range seen in groundwater in Iceland. The water in Coda reservoir shows no contamination of chosen halogen-containing alkanes and alkenes, aromatic carbohydrates, organic pesticides, and PAH. All are below the detection limit of the analytical methods used.

The results of the reaction path models carried out to assess the potential of CO2 mineralization in Coda storage reservoir show that the predicted water chemical compositions and secondary mineralogies are similar to what has previously been observed during basalt weathering and its low temperature alteration. Mixing of the CO2 injection water and the chemically variable reservoir water does not affect the overall chemical and mineralogical trends and mineralization efficiencies. The results of the simulations confirm high CO2 mineralization potential with up to 100% of the injected CO2 mineralized as calcite. However, the spatial and temporal evolution of this process has not been assessed in these models.

How to cite: Voigt, M. and Galeczka, I.: Geochemical characterization of the Coda Terminal CO2 storage site, Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16577, https://doi.org/10.5194/egusphere-egu24-16577, 2024.

EGU24-16924 | Posters on site | ERE3.7

Marine basalt complexes within reach of Europe – quo vadis? 

Achim Kopf, Melanie Dunger, and Mohamed Elfil

Carbon Dioxide Removal (CDR) approaches are essential to achieve the Paris 2015 global warming targets, as emphasized by the Intergovernmental Panel on Climate Change (IPCC) in their reports from 2021 onwards. With European legislation and ethical constraints in mind, a desirable approach to contribute to meeting ambitious climate goals would require to find safe, effective and sustainable storage sites on European territory, e.g. to avoid additional CO2 footprint for transportation or other processing steps needed.

Given that the (admittedly substantial) storage capacity of Mesozoic sandstones forming the continental socket of wider parts of Europe (with a potential to host 270 Gt of carbon dioxide) has been widely accepted, there still remain doubts that these deep, warm reservoirs are the ideal place for storage of supercritical CO2, in particular since the overburden strata are heavily fractured and far less impermeable than what would be ideal and safe – let alone the elevated temperatures in several kilometres where Buntsandstein formations encounter conditions where carbon dioxide remains in its supercritical state for geological times. In contrast, oceanic basalts have been demonstrated to host CO2 both as structural (pore volume) and mineral (precipitation as carbonate minerals) traps in a sustainable manner. In large water depth the CO2 is stable as pure carbon dioxide, and when dissolved in seawater, the carbonated equivalent is heavier than pure seawater and unlikely to escape.

With that in mind various European regional scenarios have been (re-)visited in order to assess feasibility and potential of storage. We have focused on the North Atlantic Volcanic Province (NAVP) with an estimated volume of extrusives close to 1.8 Mill. km3. The NAVP comprises various mafic and ultramafic regions between Iceland, the UK and Norway, including ocean crust, vesicular basalt and other igneous rock originating from the opening of this part of the Atlantic Ocean. We identified various corridors using ArcGIS Pro in combination with the Carbfix Mineral Storage Atlas and quantified the storage potential and associated cost in case CDR was to be carried out in these areas. Despite the large uncertainty in such numbers, the study serves to compare (among others) the Vøring and Møre basins, the Aegir ridge, Shetland and Faroer islands and neighbouring facies, and the Rockall basin and ridge. Farther from industrial centres we also investigated Iceland and the Reykjanes ridge. The work carried out is part of the AIMS3 project as part of the research mission CDRmare (www.cdrmare.de).

How to cite: Kopf, A., Dunger, M., and Elfil, M.: Marine basalt complexes within reach of Europe – quo vadis?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16924, https://doi.org/10.5194/egusphere-egu24-16924, 2024.

EGU24-16943 | ECS | Posters on site | ERE3.7

High-temperature CO2 mineralisation in basaltic rocks: Inconsistencies between laboratory experiments and numerical modelling  

Maximilian Berndsen, Selçuk Erol, Taylan Akın, Serhat Akın, Isabella Nardini, Adrian Immenhauser, and Mathias Nehler

The Nesjavellir high temperature geothermal reservoir, located in southwest Iceland, was one of the test sites for the 'Geothermal Emission Control' (GECO) project. The project involves the reinjection of exhaust gases from geothermal power plants into the subsurface for permanent storage. Numerical modelling and field data from the nearby CarbFix2 storage site at Hellisheiði indicate that even at high temperatures (< 280°C), large quantities of CO2 can be mineralised. To complement these data, we investigated the potential for CO2 sequestration in the Nesjavellir reservoir by conducting a 260 °C batch reaction experiment using a basaltic drill core sample and effluent water from the Nesjavellir injection well. We also simulated the experiment using the PHREEQC geochemical modelling program and observed significant inconsistencies between the modelled and experimental results. The experiment produced a secondary mineral assemblage dominated by zeolites, chlorites and anhydrite, with no carbonates observed. In contrast, the model predicted the formation of calcite, which did not occur during the experiment. This discrepancy is due to the model's inability to handle solid solutions and non-ideal phases adequately. During the experiment, Ca was primarily incorporated into anhydrite and a Na-Ca-zeolite, which resembles a solid solution of wairakite and analcime. However, the model did not consider this phase, which resulted in Ca being incorporated into calcite instead of zeolite.

The experimental results are consistent with previous studies that show limited carbon mineralization at higher temperatures (> 180 °C) due to the competition between carbonates and silicates for the uptake of divalent cations. In addition, a comparison with the numerical model shows that simulations of high-temperature CO2 sequestration can be misleading as they may not be able to reproduce the complexity of non-ideal silicate mineral formation, resulting in an overestimation of carbonate formation.

How to cite: Berndsen, M., Erol, S., Akın, T., Akın, S., Nardini, I., Immenhauser, A., and Nehler, M.: High-temperature CO2 mineralisation in basaltic rocks: Inconsistencies between laboratory experiments and numerical modelling , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16943, https://doi.org/10.5194/egusphere-egu24-16943, 2024.

EGU24-18314 | ECS | Posters on site | ERE3.7

Dissolution experiments on a polyphase basalt surface under conditions relevant to offshore CO2 storage. 

Isabel Lange, Marcos Toro, Christian Ostertag-Henning, Christian Hansen, Andreas Lüttge, Achim Kopf, and Wolfgang Bach

The basaltic crust attracts increasing attention as a promising lithology for CO2 storage, due to its common occurrence, its vast storage capacity in pores, and its chemical composition rich in divalent cations - required to bind the dissolved CO2 in form of carbonate minerals. The availability of divalent cations for carbonate mineralization critically depends on the dissolution kinetics of the basaltic host rock. Numerous laboratory experiments have been conducted on a variety of rock forming minerals to investigate these dissolution kinetics and mechanisms under various experimental conditions. In the case of heterogeneous materials, such as polymineralic rocks, the identification and quantification of rate determining parameters is challenging and requires further investigations.

In our experiments, we analyze the dissolution behavior of an intact, micro-crystalline basalt sample, typical for mid ocean ridge basalts, in contact with CO2-charged water under temperature and pressure conditions relevant to offshore CO2 storage. We combine flow-through dissolution experiments with Raman coupled Vertical Scanning Interferometry (RcVSI) in order to obtain spatially resolved images of both the topography and the chemical composition of the rock surface. The consecutive topography measurements by VSI allow us to quantify spatial differences in surface reactivity and examine their relation to chemical and structural properties provided by Raman spectroscopy. The data show significant differences in dissolution rates both between the different minerals and within single phenocrysts. Furthermore, the spatial heterogeneities in surface reactivity indicate an important influence of the rock texture as well.

This combination of measurements provides the means to investigate the dissolution kinetics of polymineralic rocks and to determine differences in the dissolution kinetics of different minerals simultaneously. The results provide important information about rock internal parameters that contribute to the overall dissolution behavior of the rock. The results improve our understanding of dissolution processes that are critical to the efficiency of carbonate mineralization for long-term CO2 storage in submarine basaltic aquifers.

 

How to cite: Lange, I., Toro, M., Ostertag-Henning, C., Hansen, C., Lüttge, A., Kopf, A., and Bach, W.: Dissolution experiments on a polyphase basalt surface under conditions relevant to offshore CO2 storage., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18314, https://doi.org/10.5194/egusphere-egu24-18314, 2024.

EGU24-20210 | ECS | Posters on site | ERE3.7

Study on water/rock effect of CO2 mineralization sequestration system development 

Wen-Ta Yang, Li Cheng Kao, and Sofia Ya Hsuan Liou

Currently, Taiwan is actively spearheading the development of technologies associated with achieving net-zero emissions. The government has set ambitious targets aimed at reducing greenhouse gas emissions and steering toward a more sustainable, low-carbon economy. But suffers from high urbanization and densely populated, the CO2 sequestration site is still needing careful evaluation. Whether geological sequestration storage or mineralization sequestration, the lab work for feasibility assessment is an indispensable key step before pilot. In this work we build up a tandem reaction system which the autoclave can be used to high-pressure and well-temperature controlled. Continuously flux CO2 gas to maintain system pressure for simulate carbon dioxide perfusion. A long-term water/rock reactions were performed in different minerals or water bodies. The mass flow controller (MFC) was set up to control the flow rate, while a pressure sensor and a pressure gauge were set up inside the autoclave for on-line and real-time pressure measurements during the experiment. The results were carried out by Scanning Electron Microscope-Energy Dispersive X-Ray Spectrometry (SEM-EDS) and Thermogravimetric analysis (TGA) for evaluating CO2 mineralization sequestration possibility. Most importantly, this work is a very limited research case for realistic water/rock reaction parameter experiment in Taiwan. We looking forward this contribution to be representative study for further core-flooding experiment.

How to cite: Yang, W.-T., Kao, L. C., and Liou, S. Y. H.: Study on water/rock effect of CO2 mineralization sequestration system development, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20210, https://doi.org/10.5194/egusphere-egu24-20210, 2024.

EGU24-20514 | ECS | Posters on site | ERE3.7

Trace metal scavenging from CO2-H2S injection into basaltic rocks at the CarbFix pilot and CarbFix2 sites, Iceland 

Deirdre E. Clark, Iwona M. Galeczka, Sandra Ó. Snæbjörnsdóttir, Eric H. Oelkers, Bergur Sigfússon, Ingvi Gunnarsson, and Sigurður R. Gíslason

Basaltic rock dissolution release trace and toxic elements to the aqueous phase; this process has been extensively studied in Icelandic geothermal systems. There is little information regarding their fate as a result of subsurface carbon mineralization. Samples collected from the CarbFix pilot and CarbFix2 monitoring wells at the Hellisheidi geothermal field (Iceland) were measured over time as dissolved CO2 and H2S were injected into the subsurface basalts. Results suggest that the release of any trace elements were likely scavenged into several secondary phases, including carbonate and sulfide minerals.

Although these fluids are not meant for human consumption, the aqueous trace element concentrations were generally below the WHO, EU, and Iceland drinking water standards, with a few exceptions. There were peaks in Fe during both injection experiments at the CarbFix pilot site in 2012 that exceeded proposed drinking water values, which were not sustained once the gas injections finished. In addition, As concentrations were significantly elevated at the start of the CarbFix2 gas injection in 2014, but concentrations have since greatly reduced over time to levels at or below drinking water standards although injection continued.

 

How to cite: Clark, D. E., Galeczka, I. M., Snæbjörnsdóttir, S. Ó., Oelkers, E. H., Sigfússon, B., Gunnarsson, I., and Gíslason, S. R.: Trace metal scavenging from CO2-H2S injection into basaltic rocks at the CarbFix pilot and CarbFix2 sites, Iceland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20514, https://doi.org/10.5194/egusphere-egu24-20514, 2024.

EGU24-20615 | ECS | Orals | ERE3.7

Hydromechanical impact of carbon mineralisation in basalts 

Eleni Stavropoulou, Cesare Griner, and Lyesse Laloui

Permanent CO2 storage in basalts by means of mineralisation is a promising cost-effective way to achieving reduction of carbon emissions in view of climate change mitigation. CO2 is dissolved in water before injection in the subsurface, resulting in increased trapping safety, since solubility has already taken place. Storage of dissolved CO2 in basalts at shallow depth has additional advantages such as rapid mineralisation (1-2 years), reduced drilling and monitoring cost and lower risk of leakage and induced seismicity events. However, large-scale application of this storage technology would require substantial amounts of water making it not ecologially viable. The use of seawater as a solute is an ideal alternative that is explored since recently in Iceland. Recent studies on basalt-seawater-CO2 interaction showed that the efficiency of carbon mineralisation in seawater remains significant. Batch reactor testing revealed a total mineralisation of 20% of the initial injected CO2 within five months, corresponding to carbonation rates similar to those observed in basalt-freshwater-CO2 interaction experiments (lab and field).

Carbon mineralisation can substantially alter the pore space of the basaltic material, resulting in reduction of porosity, flow properties, and consequently overestimation of the injection and storage efficiency. While geophysical monitoring is not yet available, information on the reservoir properties of basalt remains limited. In this work, the impact of CO2 mineralisation on the hydromechanical properties of a basaltic sample is studied. For the first time, injection of CO2 dissolved in saline water is considered in view of a more ecological application of the technology at large scales. Fluid flow evolution before and after exposure to CO2 dissolved in seawater is measured in terms of hydraulic conductivity and permeability under field-like conditions over a duration of 1 to 3.5 months. Permeability reduction of up to one order of magnitude suggests porosity decrease due to mineral precipitation after CO2 exposure. X-ray tomographies of the tested cores reveal a maximum porosity decrease of 1.5% at the given resolution (50 μm/px). To better understand eventual modifications in the connected pore network after mineralisation, fluid flow simulations are performed on the 3D pore network of the material that is reconstructed from the acquired x-ray images. A double porosity is proposed: macro-porosity as visible from the tomographies (pores > 50 μm) and micro-porosity representing the solid matrix porosity (pores < 50 μm). To reproduce the post-CO2 exposure flow, reduction of macro-porosity is not enough. Instead, a decrease of the solid matrix porosity is necessary by up to 30%. The experimental and numerical results suggest that mineralisation can substantially modify the pore space of the intact basaltic material and consequently impact storage efficiency if flow is not preserved.

How to cite: Stavropoulou, E., Griner, C., and Laloui, L.: Hydromechanical impact of carbon mineralisation in basalts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20615, https://doi.org/10.5194/egusphere-egu24-20615, 2024.

EGU24-20955 | Posters on site | ERE3.7

Assessing CO2 Mineralization and Sequestration Potential in Saudi Basaltic Rocks 

Mobeen Murtaza, Scott Whattam, Manzar Fawad, Nabil Ali Saraih, Muhammad Shahzad Kamal, Israa S. Abu-Mahfouz, Syed M. Shakil Hussain, and Michael A. Kaminski

To achieve a low-carbon economy, storing carbon dioxide in the Earth's crust by converting it into minerals within basalt rocks is a promising method. This study explores CO2 interaction with Saudi scoriaceous (SB) and dense (DB) basalts to assess their capacity for CO2 storage. SB contains augite, olivine, clinopyroxene, and enstatite, while DB is composed of anorthite, augite, olivine, orthopyroxene, and diopside.

SB and DB samples were aged in a supercritical CO2/brine system at 50°C and 1450 psi for a month. Interfacial tension (IFT) was studied across various pressures at 50°C, and contact angles were measured at room conditions and under the specific conditions of 1450 psi and 50°C. Surface compositional analysis of SB and DB was conducted using scanning electron microscopy (SEM), x-ray fluorescence (XRF), and x-ray diffraction (XRD) before and after CO2 exposure. Micro-CT scans were performed pre- and post-exposure to assess in situ mineralization. DB, characterized by minimal porosity and permeability, showed potential for CO2 interaction predominantly on fractured surfaces. However, the DB core sample lacked fractures, so the surface area was the primary place of interaction. In contrast, SB displayed considerable porosity and permeability, indicating a broader area for potential CO2 interaction.

The results from the IFT measurements revealed a pressure-sensitive pattern, with significant alterations at lower pressures and smaller ones at higher pressures, essential for assessing CO2 storage potential. Under standard conditions, SB and dense DB exhibited water-wetting properties. However, in a supercritical CO2/Brine environment, their wettability significantly changed: contact angles increased from 32.9° to 85.8° for DB, and  from 42.6° to 104° for SB, indicating a move towards intermediate water wetness in a CO2 environment. These results highlight the potential for CO2 storage in basaltic formations and the complex dynamics of CO2-brine-rock interactions. Micro CT and SEM analyses showed dissolution, precipitation, and surface variations in the rocks during brine-CO2 exposure. Specifically, SB demonstrated considerable changes in pore structure and surface, indicating a substantial interaction with CO2. On the other hand, DB, being non-porous in nature, primarily exhibited surface changes. These post-exposure transformations confirm effective CO2 interaction with the rocks, further supporting the feasibility of CO2 sequestration in basalt rocks.

Our in-depth understanding of changes in interfacial tension, wettability, and rock morphology is crucial for safely and efficiently storing CO2 in basaltic rocks. This knowledge contributes to environmental sustainability and innovative climate change mitigation, marking a significant step towards a greener future in Saudi Arabia.

How to cite: Murtaza, M., Whattam, S., Fawad, M., Saraih, N. A., Kamal, M. S., Abu-Mahfouz, I. S., Hussain, S. M. S., and Kaminski, M. A.: Assessing CO2 Mineralization and Sequestration Potential in Saudi Basaltic Rocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20955, https://doi.org/10.5194/egusphere-egu24-20955, 2024.

EGU24-21858 | ECS | Posters on site | ERE3.7 | Highlight

The geological potential of in-situ CO2 mineral storage within onshore UK formations 

Angus W. Montgomery, Chris Holdsworth, Emma Martin-Roberts, Ian Watt, and Stuart Gilfillan

Carbon capture and storage (CCS) is essential for meeting the UK’s legally binding net-zero targets by 2050. In-situ mineralisaton of CO2 in mafic rock has been established as a rapid, secure, and affordable method of geological CO2 storage by the Carbfix projects in Iceland.

In this study, we use geochemical, stratigraphic, and volumetric analyses to assess the suitability of UK onshore mafic and ultramafic formations for in-situ mineral storage of CO2. We find that the total Mg2+, Ca2+, Fetot. oxide content of some UK formations is comparable to the geological reservoirs utilised by Carbfix in Iceland. We determine the volumes of the studied formations using a combination of boreholes, digitised cross sections and GIS calculated surface areas. We find that there are significant volumes of reactive rock available for CO2 mineral storage in the UK.

Using a method developed by Callow et al. (2018) we determine the reactive surface area within connected pore volumes in the most suitable formations for in-situ CO2 mineral storage. Our results indicate that onshore UK formations have the theoretical potential to store multiple gigatonnes (Gt) of CO2. This is equivalent to the storage of decades’ worth of annual UK industrial CO2 emissions. 

Our findings highlight that in the Antrim Lava Group alone, there is between 1.6 and 21.9 million km2 of reactive surface area available for CO2 mineral storage. This equates to a potential theoretical CO2 storage capacity of between 8 and 110 GtCO2. These results demonstrate that the theoretical CO2 mineral storage capacity of onshore mafic and ultramafic rocks in the UK far exceeds the CO2 storage requirement for the UK to achieve net-zero GHG emissions by 2050. Future research efforts should prioritise the investigation of connected porosity, reactive surface area, impact by alteration and mineralisation rates specific to the formations identified by this study.

How to cite: Montgomery, A. W., Holdsworth, C., Martin-Roberts, E., Watt, I., and Gilfillan, S.: The geological potential of in-situ CO2 mineral storage within onshore UK formations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21858, https://doi.org/10.5194/egusphere-egu24-21858, 2024.

EGU24-21955 | ECS | Posters on site | ERE3.7

Lab-based assessment of engineered CO­2 mineralization in mafic rock reservoirs 

Ian Watt, Ian Butler, Florian Fusseis, Ian Molnar, James Gilgannon, Stuart Haszeldine, and Stuart Gilfillan

Understanding how in-situ mineralization of CO2 affects the porosity and permeability of the host rock is critical to assessing the viability of basalt reservoirs as carbon dioxide repositories. Precipitating carbonate minerals have the potential to fill primary porespace and decrease permeability, reducing injectivity and overall reservoir capacity. Laboratory experiments that induce carbon mineralization in basalt under controlled conditions can inform how fluid transport properties evolve in geological storage reservoirs.

Here, we present time-resolved 3D datasets acquired using a novel x-ray transparent cell that allows carbon mineralization in basalt to be documented on the grain scale through time using x-ray microtomographic imaging (µCT). Our 4DµCT data aim to document the formation of carbonate mineral species, via ion exchange between dissolved inorganic carbon and the divalent cations of primary minerals in the basalt sample. We use the 4DµCT dataset to track sample deformation, changes in porosity, and to model the permeability evolution on the grain scale. Our 4DµCT data (Figure, below), and other post-reaction analyses, document the in-situ formation of carbonate mineral species.

Our experiments utilise cylindrical cores of basalt with a diameter of 10 mm and a central 2 mm bore and react these with water-dissolved CO2. The second phase of the experiments is a switch of injection fluid to an aqueous solution of NaHCO3 equilibrated with CO2 During the ongoing experiment, the sample has been repeatedly sealed to maintain fluid pressure, disconnected from benchtop apparatus, and imaged using a µCT scanner. 

Exceptionally long operando experiments such as ours can be of particular use in assessing reservoir potential of prospective carbon mineral storage sites by recreating subsurface conditions unique to each location. The apparatus can investigate the evolution of physical rock properties over time periods relevant to field operations (months/years).

How to cite: Watt, I., Butler, I., Fusseis, F., Molnar, I., Gilgannon, J., Haszeldine, S., and Gilfillan, S.: Lab-based assessment of engineered CO­2 mineralization in mafic rock reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21955, https://doi.org/10.5194/egusphere-egu24-21955, 2024.

ERE4 – Raw materials and resources

As conventional hydrocarbon resources become depleted and theoretical innovations in hydrocarbon exploration advance, unconventional resources have gained substantial attention from researchers and explorers in recent decades. In the global energy consumption structure, unconventional shale gas progressively assumes a crucial role in the overall energy landscape. This research is motivated by the high probability of deriving gas accumulations encountered in drilling on the northwestern Anatolia (Akcakoca area) offshore from Paleozoic-aged rocks. Studied black shales from the Silurian Findikli Formation in the Sakarya region of northwestern Anatolia are one of the alternative unconventional resources.

Working with outcrop samples, this work evaluates the unconventional gas potential by performing geochemical characterization of these black shale samples. Studied samples were analyzed by Rock-Eval Pyrolysis. The present-day total organic carbon (TOCpd) contents range from 0.54 to 1.57 wt.%. High Tmax (up to 504oC) and low Hydrogen Index (HI) values (4-38 mg HC/g TOC) indicate that these shales are thermally over-mature and seem to be a spent hydrocarbon source rock. The remaining hydrocarbon generative potential (S1+S2) of 0.06–0.49 mg HC/g rock also supports this assessment. The recent organic matter type is Type IV kerogen which can yield limited gas products plotting on the H/C versus O/C atomic ratios on the modified Van Krevelen diagram. According to the interpretive of shale gas potential parameters based on Jarvie’s equation reconstructed these black shales originally may have good to very good source rock potential, with the calculated average original values of TOCo being 1.72 wt.% and HIo is 448 mg HC/g TOC. It can be concluded that the characteristics of studied shales seem to be nearly compatible with those of Utica shales in terms of the hydrocarbon generative potential. The studied black shales have lost 95% of their original hydrocarbon potentials, and seem to be a spent hydrocarbon source rock, indicating good risk for gas. However, the source rock may be very deep and deformed from the past to the present day, considering the paleogeographical location and geological evolution of the study area. Further research is required.

Keywords: Unconventional Gas Potential, Source Rock, Geochemical Characteristics, Silurian Black Shales, Northwestern Anatolia (Türkiye)

How to cite: Doner, Z.: Unconventional Gas Potential of Black Shales from Silurian Findikli Formation in northwestern Anatolia, Türkiye: Characterization of Geochemistry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-738, https://doi.org/10.5194/egusphere-egu24-738, 2024.

EGU24-820 | ECS | Orals | ERE4.1

Machine Learning-based Mineral Prospectivity Mapping: Exploring the Role of Negative Training Labels to Enhance Predictive Models 

Nyah Bay, Kyubo Noh, Mohammad Parsasadr, and Andrei Swidinsky

Mineral Prospectivity Mapping (MPM) is an important tool to identify areas with significant potential to host mineral deposits. Recent advancements in computational sciences, especially the advent of Machine Learning (ML), have enhanced MPM's capabilities. ML techniques enable a higher degree of data integration and extraction compared to traditional statistical methods such as Weights of Evidence, enhancing the accuracy and efficiency of identifying mineral exploration zones. When using ML techniques for MPM, the influence of negative training labels (ie. barren areas with no mineralization) remains a neglected research area, and this study investigates the influence of such label selection to optimize predictive models for Canadian critical mineral exploration.

Previous approaches to ML-based MPM often adopted a random assignment of negative training labels wherever positive training labels were absent. This study aims to refine this method, striving for a more systematic approach in negative label selection. The evolution of MPM, transitioning from traditional statistical methods to modern ML algorithms, signifies a shift towards heightened accuracy and efficiency. Prior research underscores the importance of balanced representation between mineralized and non-mineralized labels in ML models. Techniques such as Synthetic Minority Over-Sampling (SMOTE) and Positive and Unlabelled Learning (PUL) have been highlighted in previous studies, emphasizing the necessity of effectively handling negative training labels to prevent biases and enhance model performance. While SMOTE and PUL synthetically balance datasets by either oversampling minority classes or considering only positive and unlabeled instances, this study focuses on leveraging public exploration data to identify real negative training labels and provide a more authentic representation of non-mineralized areas without synthetic augmentation.

Using datasets compiled by the Geological Survey of Canada containing discoveries & occurrences of magmatic Ni (±Cu ±Co ±PGE), this research incorporates geological, geochemical, and geophysical data from established sources. Public exploration data will be used to identify areas devoid of magmatic Ni (±Cu ±Co ±PGE). These locations will serve as negative training labels for this study. Our particular choice of ML model is a Gradient Boosting Machine (GBM), and validation involves comprehensive evaluation techniques such as confusion matrices and receiver operating characteristic curves to assess model performance.

How to cite: Bay, N., Noh, K., Parsasadr, M., and Swidinsky, A.: Machine Learning-based Mineral Prospectivity Mapping: Exploring the Role of Negative Training Labels to Enhance Predictive Models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-820, https://doi.org/10.5194/egusphere-egu24-820, 2024.

EGU24-1272 | Orals | ERE4.1

Geochemical behavior of gold and critical metals in the Goongarrie Ni-laterites, Western Australia 

Walid Salama, Louise Schoneveld, and Michael Verrall

The Goongarrie South, situated northwest of Kalgoorlie in Western Australia, hosts a global resource (60Mt) of lateritic Ni-Co deposits at 1% Ni and 0.07% Co. The Goongarrie lateritic Ni-Co deposit extends over a strike length of 7.5 km and averages approximately 800m in width and 40m in thickness. These deposits originated from the weathering of serpentinized dunite. The lateritic profile is subdivided into lower saprolite, dominated by carbonate, talc, serpentine, chlorite, and mica, and upper ferruginous saprolite, representing the economic Ni-Co laterite, and dominated by goethite and hematite. The ultramafic index of alteration (100 x [(Al2O3+Fe2O3(T)/(SiO2+MgO+Al2O3+Fe2O3(T)]) for the Ni-Co laterite is >60, contrasting with <60 in the lower saprolite and saprock. The laterite profile thickens up to 120 m over shear zones. In this study, we investigated the geochemical behavior of gold and some critical metals (REE, PGE, Sc, Ni, Cr, Mn, Co) in the Goongarrie South lateritic nickel deposits, using bulk and in-situ mineralogical, and geochemical methods. Our results show that gold and critical metals are concentrated in different horizons of the lateritic profile. Gold underwent leaching by acidic, halogen-rich, hypersaline groundwater, and has been enriched near the contact between the Ni-Co laterite and lower saprolite and saprock over shear zones, where the pH gradient increased. Additionally, gold is concentrated in paleoredox fronts within the Ni-Co laterite. The Au mineralization is Ag-poor, and occurs as cavity-filling, microcrystalline grains, and aggregates, indicating its supergene origin. Laser ablation ICP-MS mapping indicates that Ni was released from olivine in the lower saprolite and reprecipitated in nimite (Ni chlorite), while Sc is concentrated in serpentine and mica in the lower saprolite. In the Ni-Co laterite, Cr, Ti, V, Sc, Sb, and Y remained immobile; these elements are bound to Fe oxides and clays. Mobile elements such as Ni, Co, Li, Mo, W, Zn, Ce, Ru, and Pb are associated with Mn oxides at the base of the lateritic profile. The ΣREEs content in the laterite profile reaches up to 375 ppm. Cerium shows a weak positive correlation with the rest of REE, while positive Ce anomalies are associated with zones of Mn and Ce oxide enrichment. While there is no known magmatic sulfide mineralization associated with the host rock, chromite with Ru <0.15 ppm and inclusions of gold, Ni-Co-Cu-PGE-bearing sulfides, and sulfarsenides emerge as potential indicators for sulfide saturation. 

How to cite: Salama, W., Schoneveld, L., and Verrall, M.: Geochemical behavior of gold and critical metals in the Goongarrie Ni-laterites, Western Australia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1272, https://doi.org/10.5194/egusphere-egu24-1272, 2024.

EGU24-2491 | Orals | ERE4.1

Assessment of geophysical methods in the discovery of karst bauxite deposits in the Dinarides 

Franjo Šumanovac, Josipa Kapuralić, Luka Perković, and Ivica Pavičić

 

Geophysical exploration was carried out on karst bauxite deposits in the Posušje area in Bosnia and Herzegovina, which generally represent the problem of researching bauxite deposits in the Dinarides and similar geological models in the Mediterranean. Karst-type bauxite deposits are found in very complex geological models and were deposited in depressions in carbonate bedrock during numerous emersions on the Adriatic carbonate plate. Carbonate or clastic rocks can be found as the hanging wall of the deposits. Due to the complex lithological and structural relations, very irregular shapes of the deposits and their relatively small dimensions, the discovery of karst-type bauxite deposits is a very demanding geophysical task. That is why the published literature falls short in offering solutions for this very complex problem. So, the fundamental question is whether very irregular bauxite deposits whose dimensions are generally small can be detected by geophysical exploration?

Basic near surface geophysical methods, electrical resistivity tomography and seismic refraction, as well as magnetometry were applied in the exploration, which was carried out in two phases. In the first phase, geophysical methods were applied to already discovered bauxite deposits in order to determine whether geophysical responses correlate with bauxite deposits and to evaluate the efficiency of each method. Geophysical measurements were performed at several microlocations, and in the area of Mratnjača were carried out immediately after the deposit discovery, which was subsequently mapped with a very dense network of exploratory boreholes and was very well defined. In the second phase, measurements were performed in an microlocation selected by geological prospecting in order to discover potentially new bauxite deposit.

The characteristic responses of bauxite deposits are expressed on the resistivity models of tomographic profiles as zones of lower resistivities within carbonate rocks, and on the velocity models of refraction profiles as velocity inversions. The responses are much clearer on resistivity models, so the electrical tomography should be considered as a fundamental method in the exploration of karst bauxite deposits. Seismic refraction can contribute to a better characterization of deposits and reduce the interpretation ambiguity, thereby increasing the efficiency of geophysical exploration. In the last case, the electrical tomography can be applied independently to give satisfactory exploration results. On the other hand, the seismic refraction should be combined with the electrical tomography, because in some cases the depth coverage is greatly reduced due to distinct velocity inversions. Unfortunately, magnetometric measurements showed there are no magnetic anomalies that could be associated with bauxite deposits, that is, there are no magnetic minerals in the deposit.

Acknoledgments

This exploration was carried out in the AGEMERA project (Agile Exploration and Geo-modelling for European Critical Raw Materials) which has received funding under the European Union's Horizon Europe research and innovation programme under grant agreement No 101058178.

How to cite: Šumanovac, F., Kapuralić, J., Perković, L., and Pavičić, I.: Assessment of geophysical methods in the discovery of karst bauxite deposits in the Dinarides, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2491, https://doi.org/10.5194/egusphere-egu24-2491, 2024.

EGU24-3882 | ECS | Orals | ERE4.1

The delineation of graphite deposits in Lower Austria using the Transient Electromagnetic method 

Jorge Luis Monsalve Martinez, Lukas Aigner, Adrian Flores-Orozco, Clemens Moser, Philipp Högenauer, and Alexander Römer

The European Commission classifies graphite as a critical raw material, given its importance in refractory and high-tech applications, including the production of lithium-ion batteries. Many of Austrias graphite deposits are situated in and around the so-called “Drosendorf-Deckensystem” in Lower Austria. As those sites have been extensively mined out in the near-surface and are heavily weathered, the current interest of the potential assessment primarily focuses on the spatial extent of the graphite deposits, with particular interest in the deep continuation of these graphite deposits. Geological cross-sections are a standard approach for understanding subsurface graphite distribution, relying on available structural, geochemical, and/or lithological data. However, such information is primarily derived from surface observations, limited to exposed surfaces or outcrops. Geophysical methods can play a crucial role in extending the interpretation of geological cross-sections both horizontally and vertically. Due to the high electrical conductivity of graphite, electromagnetic and electrical methods like the Transient Electromagnetic (TEM) and the Induced Polarization (IP) are commonly applied for exploration. The IP method complements traditional electrical resistivity methods by measuring not only subsurface conductivity but also variations in the electrical capacitive properties (polarization) at low frequencies. In this study, we explore the feasibility of integrating the interpretation of IP and TEM measurements. The latter is known for its cost-effective coverage of large areas with high resolution and depth of investigation, compared to other geophysical methods. For that purpose, multiple TEM soundings were acquired in a ca. 4 km long profile between Berging and Kochholz in Lower Austria, situated in the geological section called “Drosendorf-Deckensystem”. The inversion of TEM data revealed distinct high-conductivity anomalies (100 – 200 mS/m) at approximately 40 m depth, attributed to the presence of graphite. A parallel comparison with two 160 m – 250 m long Time-Domain IP profiles confirms the graphite presence, attributed by high conductivity and high polarization (σ’ > 200 mS/m, σ” > 20 mS/m). Integrating these results along a geological cross-section improved the delineation and understanding of graphite deposits at depth and their correlation with lithological features in Lower Austria. Furthermore, these findings confirm that acquiring physical property models related to TEM and IP surveys has the potential to enhance mineral exploration.
This research work was co-financed by the Federal Ministry of education, science and research and supervised by the Federal Mining Authority of Austria within the framework of the VLG83 project (Raw Material research initiative).

How to cite: Monsalve Martinez, J. L., Aigner, L., Flores-Orozco, A., Moser, C., Högenauer, P., and Römer, A.: The delineation of graphite deposits in Lower Austria using the Transient Electromagnetic method, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3882, https://doi.org/10.5194/egusphere-egu24-3882, 2024.

EGU24-4856 | Posters on site | ERE4.1

Multiple suppression for marine seismic data with strong shielding layer 

Jiajia Yang, Xiaojie Wang, Huaning Xu, Hong Liu, Zhonghui Yan, and Jianwen Chen

The study of multiple wave suppression methods has always been a difficulty of marine seismic data processing. At present, multiple wave suppression methods can be roughly divided into two categories: the first type is filtering methods, the second type is the wave dynamics and kinematic theory method. When the water depth in the study area is shallow, and strong seabed oscillations are formed between the seabed and the sea surface. The surface multiple suppression method (SRME) is not ideal for suppressing such short period seabed multiples. The deterministic seabed multiple prediction method (DWMP) can more accurately predict shallow water seabed periodic multiples. Long period multiples other than seabed multiples require surface multiple prediction (SRME) to suppress multiples.

When the research area is not only shallow in water depth, but also has a strong wave impedance interface in the formation, the difficulty of suppressing long-period multiples further increases. This is because various types of strong energy multiples, such as surface multiples, seabed multiples, and interlayer multiples, are formed between the sea surface and the strong wave impedance interface. The energy of multiples is one order of magnitude higher than that of weak effective reflections below the strong wave impedance interface. The strong energy of wide-angle multiples in the mid to far triangular region affects the effective utilization of reflected waves at mid to far offset distances. Diffraction multiples are developed in areas with severe fluctuations in the impedance interface of strong waves. Diffraction multiples are difficult to suppress using conventional multiples, and strong energy diffraction multiples can produce migration phenomena, affecting imaging in mid to deep layers. The effective suppression of various multiples is the key and difficult point in seismic data processing under strong shielding layer conditions.

Based on the characteristics of multiples under strong shielding layer conditions in shallow water, targeted suppression strategies were studied: using three methods to predict multiple wave models: deterministic seabed multiple prediction, deterministic seabed multiple prediction and surface multiple prediction, and surface multiple prediction. Firstly, frequency division combined with adaptive subtraction was used to achieve simultaneous suppression of short period seabed multiples and long period surface multiples. Then, application of CMP domain for high precision radon removal of multiples with dynamic calibration time difference. Finally, residual multiple suppression method is applied in the common offset domain to remove strong energy diffraction multiples. Through the suppression strategy proposed in this article, various types of multiples under the conditions of shallow water strong shielding layers can be effectively suppressed, thereby obtaining weak reflection signals in the middle and deep under the strong shielding layer. Through the calculation examples in the study area, it can be seen that the suppression strategy proposed in this article can suppress multiples interference while protecting effective reflection information. It is of great significance for imaging inside buried hill, imaging under volcanic shielding layers, and imaging under gypsum-salt layer.

How to cite: Yang, J., Wang, X., Xu, H., Liu, H., Yan, Z., and Chen, J.: Multiple suppression for marine seismic data with strong shielding layer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4856, https://doi.org/10.5194/egusphere-egu24-4856, 2024.

EGU24-6515 | Posters on site | ERE4.1

Towards AI-driven real-time deposit modeling: a case study in southern Brazil 

Ítalo Gonçalves and Everton Frigo

Mineral exploration and resource estimation play pivotal roles in the mining industry, driving the need for accurate and comprehensive data about mineral deposits. Traditionally, drill core samples have been the primary means of obtaining crucial information regarding the size, shape, and mineral composition of deposits. However, the cost associated with drilling limits the number of samples that can be acquired, posing challenges to achieving a thorough understanding of a mineralized area. In response to these challenges, the mining industry is increasingly turning to cutting-edge technologies to enhance exploration efficiency and reduce costs, such as aerial photogrammetry, hyperspectral imaging, and core scanning. These technologies offer the advantage of acquiring data over larger areas in a relatively short period, providing valuable insights into the geological characteristics of a site. In the context of developing mines, each round of blasting uncovers fresh rock surfaces that harbor new geological information. Leveraging this opportunity to gather real-time data presents an exciting prospect for optimizing mineral exploration. By systematically collecting and processing information from newly exposed surfaces, it becomes possible to enhance the insights obtained from conventional core samples. This research introduces a case study exemplifying the implementation of this paradigm shift in a marble quarry located in southern Brazil. Here, a convolutional neural network is employed to interpret geological features in aerial photographs. Subsequently, the interpreted data is fed into a photogrammetry software, generating a labeled point cloud that complements information derived from traditional core samples. The synergy between aerial data and core sample information allows for the creation of highly detailed lithology models, enabling more accurate short-term forecasting of stripping ratios. A key aspect of this work involves the development and utilization of an in-house Gaussian process implementation for lithological modeling. This technique not only provides insights into the size and shape of the orebody but also offers an invaluable uncertainty estimate. The results from this case study demonstrate the potential of this paradigm shift in mineral exploration and mining practices. Ultimately, this research aims to showcase a pathway towards a more economical, environmentally friendly, and sustainable future for the mining industry.

How to cite: Gonçalves, Í. and Frigo, E.: Towards AI-driven real-time deposit modeling: a case study in southern Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6515, https://doi.org/10.5194/egusphere-egu24-6515, 2024.

EGU24-6901 | ECS | Orals | ERE4.1

Predicting global porphyry copper prospectivity using positive-unlabelled machine learning 

Christopher Alfonso, Dietmar Müller, Ben Mather, and Tristan Salles

The majority of the world’s known copper reserves is contained in porphyry copper deposits. These deposits are understood to form along subduction zones within the magmatic arc, though the exact contributions to this process of different factors within the subducting and overriding plates are not entirely certain, hampering efforts to develop large-scale prospectivity models for this deposit type. Previous efforts to tackle this problem through the use of data-driven machine learning methods have shown promise, but have been hindered by the relative paucity of fully labelled data required for training classification models. Here we present a suite of models trained using a semi-supervised positive-unlabelled (PU) algorithm, allowing the classifier to be created from data of which only a small subset of one class is labelled: in this context, known porphyry copper deposit locations. These models can be used to create time-dependent prospectivity maps representing the probability of a deposit forming at a given place and time, while model inspection can provide deeper insight into the processes behind the genesis of these deposits, at both a global and regional scale. Furthermore, deep-time erosion rate estimates extracted from global landscape evolution models are used to explore the uplift and erosion histories of known porphyry copper deposits in order to better understand the potential for these deposits to survive to the present day. These two factors of deposit formation and preservation are combined into a powerful prospectivity model, with the potential to facilitate the identification of possible new prospective zones along the world's subduction zones through time and help minimise the environmental and financial costs of mineral exploration.

How to cite: Alfonso, C., Müller, D., Mather, B., and Salles, T.: Predicting global porphyry copper prospectivity using positive-unlabelled machine learning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6901, https://doi.org/10.5194/egusphere-egu24-6901, 2024.

EGU24-7758 | Orals | ERE4.1

FIELD VNIR-SWIR SPECTRORADIOMETRY FOR CLASSIFICATION OF MATERIALS IN THE VALDEFOREZ DEPOSIT (SPAIN) ACCORDING TO THE Li CONTENTS. 

Emilia García Romero, Santos Barrios, David Valls, and Mercedes Suárez

The Li mineralization of Valdeflórez (Cáceres province, Spain) is related to an extensive metasomatism of Ordovician metasedimentary rocks due to the circulation of B- and Li-rich magmatic hydrothermal fluids associated probably with a granite dome (Torres-Ruiz, et al., 1996). Li-rich micas mainly, and other Li-rich minerals like amblygonite-montebrasite, appear as consequence of this hydrothermal alteration. The aim of this study is to evaluate the use of the VNIR-SWIR spectroradiometry to the materials classification according to the Li content during the exploitation mining works and to the mining prospection in similar areas. The results of a study conducted by VNIR-SWIR portable spectroradiometry on 335 samples coming from representative cores of the mineralized area are shown. Complementary, a mineralogical study by XRD and chemical analysis by ICP were performed. Visible and infrared wavelength ranges were studied separately, and a classification of the high-resolution spectra was done to compare with the chemical and mineralogical composition of the samples. The spectra were classified into six groups according to their morphology in the near and short-wave IR range, and these groups correspond to a different mineralogy of major components, as logical.  However, there is not a clear relation among these groups and the Li-content because Li is mainly in micas as octahedral substitutions, which influence on the spectral features is neglectable. A higher content in micas does not imply a higher content in Li. Consequently, a spectral signature of Li could not be determined, because Li is not directly related to the content of a certain mineral, micas in this case. As a conventional spectral signature is not useful in this case, because it classified mineralogy but not Li-content, a detailed study of the hight resolution spectra obtaining different parameters (both from the spectra and from the second derivatives of the spectra) was performed. The joint statistical treatment of the hyperspectral, mineralogical, and chemical data allowed us to find a plot of the materials classification according to the Li content from the spectral data which means a very fast procedure for classification that could be automatized though IA.

Acknowledgement: TED2021-130440B-I00 funded by MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR

Torres-Ruiz, J., Pesquera, P., Gil, P., Casas, J. 1996. Tourmalinites and Sn-Li mineralization in the Valdeflores area (Cáceres, Spain). Mineralogy and Petrology 56:209-223.

How to cite: García Romero, E., Barrios, S., Valls, D., and Suárez, M.: FIELD VNIR-SWIR SPECTRORADIOMETRY FOR CLASSIFICATION OF MATERIALS IN THE VALDEFOREZ DEPOSIT (SPAIN) ACCORDING TO THE Li CONTENTS., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7758, https://doi.org/10.5194/egusphere-egu24-7758, 2024.

EGU24-7868 | ECS | Posters virtual | ERE4.1

Advanced Computational Analysis of Roof Stability in Highwall Phosphate Mining Operations 

Mohamed Yassir Sadki, Murat Karakus, Khalid Amrouch, Bouazzaoui Eljabbar, and Abdelhadi Khaldoun

Abstract:
Strip mining is typically preferred for near-surface, tabular deposits such as phosphate. 
Khouribga, home to Morocco’s largest phosphate deposit, contributs significantly to the 
nation’s phosphate output. However, a slight dip in the phosphate deposit suggests that strip 
mining may become less viable in the future. To sustain phosphate production efficiently, 
transitioning from surface to underground mining through highwall mining could be an 
effective solution. This method, involving the recovery of phosphate using continuous miners, 
necessitates stable roof conditions.
To evaluate roof stability in highwall mining, both with and without web pillars, we will employ 
a three-dimensional finite difference method. Firstly, field rock mass properties, including joint 
frequency, persistency, infills and orientations and mechanical parameters, will be determined 
for inclusion in the numerical model. The generalized Hoek-Brown failure model, in 
conjunction with the Geological Strength Index (GSI), will be utilized to analyze rock mass 
behavior. For intact rock behavior, triaxial tests will be conducted to acquire Hoek-Brown 
failure parameters. These parameters will inform the construction of realistic 3D models using 
FLAC3D software, enabling the simulation of various underground working scenarios to 
identify the optimal mine layout that ensures high production rates and minimizes roof stability 
issues.
An economic analysis will also be conducted to assess the feasibility of this method. This 
analysis will help in optimizing the dimensions of highwall mining parameters and selecting 
the best scenario through the Mineable Shape Optimizer (MSO). This planning tool will 
additionally aid in forecasting the recovery and dilution rates associated with the 
highwall mining method.
Keywords:
Highwall mining, Phosphate, Khouribga, Roof stability, GSI, Rock mass classification, HoekBrown failure model, Economic analysis, MSO

How to cite: Sadki, M. Y., Karakus, M., Amrouch, K., Eljabbar, B., and Khaldoun, A.: Advanced Computational Analysis of Roof Stability in Highwall Phosphate Mining Operations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7868, https://doi.org/10.5194/egusphere-egu24-7868, 2024.

EGU24-7969 | ECS | Orals | ERE4.1

Predicting petrophysical properties from hyperspectral borehole data 

Akshay Kamath, Moritz Kirsch, Samuel Thiele, and Richard Gloaguen

Recent research has highlighted significant correlations between hyperspectral data and the petrophysical properties of geological formations. Petrophysics acts as the link between geology and geophysics, and is crucial for constraining geophysical inversions, regional characterisation and mineral exploration. In this study, we employ various machine learning methods to predict P-Wave velocities using hyperspectral borehole data, with a focus on cross-validation between different boreholes in the same region. Our dataset includes 4022 paired observations of P-wave velocities, obtained from downhole sonic logging in one borehole, and corresponding hyperspectral data spanning visible-near (380–970 nm), shortwave (970–2500 nm), midwave (2700–5300 nm), and long-wave (7700–12300 nm) spectra, averaged over a 10 cm x 5 cm area. We utilised principal component analysis (PCA) for dimensionality reduction. The initial PCA stage extracted 10 principal components from each sensor type, which were then integrated. A subsequent PCA stage was conducted to reduce inter-sensor correlation, yielding 10 composite features that represent the variability across the complete VNIR-LWIR spectrum.

To validate our model, we conducted tests using 1160 pairs of analogous measurements from a different borehole within the same geological region. The model demonstrated impressive predictive capabilities, particularly with Support Vector Regression (SVR) and Artificial Neural Networks (ANN). The test set yielded R2 scores of 0.758 for SVR and 0.811 for ANN, indicating strong predictive accuracy. Building upon this success, our future work will expand the scope of prediction to include various other petrophysical properties critical to geophysical characterization and mineral exploration, such as S-Wave velocity, magnetic susceptibility, and rock density, properties which are critical for geophysical characterization and mineral exploration.

How to cite: Kamath, A., Kirsch, M., Thiele, S., and Gloaguen, R.: Predicting petrophysical properties from hyperspectral borehole data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7969, https://doi.org/10.5194/egusphere-egu24-7969, 2024.

On a global level, clean transition, energy transition and electrification of transport, among other things, require a lot of strategic or critical raw materials. In Europe, too, the importance of increasing the self-sufficiency of raw material production has come to light in order to secure the operating conditions of industry supporting the green transition.

For promoting the sustainable use of raw materials in Eastern and Northern Finland, it has been decided to intensify cooperation between regional, national and international actors.

In the regional level, the development of the mineral industry is carried out by the regional Mining Hubs. Nationally, it will be significant in Finland during 2024 to develop a new mineral strategy to promote the growth of the mineral and battery cluster in order to enable a clean and digital transition. The aim of the new strategy is to produce a common view of the current situation of the Finnish mineral cluster, policy objectives, main lines and necessary measures, including the development of a circular economy. At the European level the new Critical Raw Materials Act aims to ensure the EU's access to a secure, diversified, affordable and sustainable supply of critical raw materials and also strengthening Europe's strategic autonomy.

Between the actors of regional, national and EU level, the R&I and training organisations play a key role in developing cooperation. In the Eastern and Northern Finland region, the Geological Survey of Finland, the University of Oulu, Kajaani University of Applied Sciences and The Federation of Education in Central Ostrobothnia have decided to join forces to enable this collaboration. A special tool for this is the JTF project “Development of the mining sector in Lapland, Northern Ostrobothnia, Kainuu and Central Ostrobothnia” (KAKE).  The planned measures include e.g. international networking, competence development, workshops, innovating new R&I projects and linking companies to project activities.

How to cite: Pihlaja, J.: Development of mineral sector cooperation in Eastern and Northern Finland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10182, https://doi.org/10.5194/egusphere-egu24-10182, 2024.

The Mineral Prospectivity Mapping (MPM) methodology can be used to delineate favorable mineral exploration areas and minimize time and costs. The mineral deposits in Finland are an ideal testing ground for these methods due to limited outcrops, thick overburden because of soil cover and dense vegetation and snow cover during long winters. Here, we apply MPM to predict favorable areas for Iron Oxide-Copper-Gold (IOCG) deposits in the Kolari region, northwestern Finland. We use a GIS-based knowledge-driven approach (fuzzy logic overlay), which is integrating evidential layers derived from geological (scale-free geology map), geochemical (till and bedrock samples), and geophysical data (magnetic, radiometric, electromagnetic measurements and gravity worms). The regional-scale analysis aimed to evaluate various mineral system components specified for IOCG deposits, including the anomalies of elements in till and rock geochemistry (i.e., Au, Cu, Co, Fe, and Th), pathways, energy sources/drivers, traps, and the relevant geological factors influencing the ore-forming processes. Utilizing the Centered Log-Ratio transformation (CLR) proves beneficial in enhancing the identification of weak anomaly areas and improving the prospectivity assessments by directing attention to relevant geological features. The produced prospectivity map shows a positive association between known IOCG deposits and high-favorability areas, and it also indicates new promising targets. Receiver Operating Characteristic (ROC) analysis and average Area Under the Curve (AUC) values consistently yielded scores > 0.7 which could be considered favorable outcomes (promising targets).

How to cite: Khammar, F.: Translating mineral systems criteria into a prospectivity model; Kolari region, Finland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12082, https://doi.org/10.5194/egusphere-egu24-12082, 2024.

EGU24-12933 | ECS | Orals | ERE4.1

In situ Rhenium (Re) quantification by pXRF in Molybdenite from porphyry-epithermal deposits (Thrace, NE Greece) 

Marjolène Jatteau, Jean Cauzid, Alexandre Tarantola, and Panagiotis Voudouris

Even if natural occurrence of Re can be found as rheniite (ReS2), most Re substitutes to Mo in molybdenite (MoS2), which explains why Re is usually a by-product of Cu-Mo deposits. In Thrace region (NE Greece), molybdenite can be enriched up to 4.7 wt% in Re in porphyry-epithermal deposits (Voudouris et al., 2013). Now, spectroscopic portable tools (e.g. pXRF) allows to directly detect Re in the field. First qualitative results obtained by pXRF show that is possible to know in which deposits from Greece the molybdenite is the most enriched without the necessity of long and costly laboratory measurements (EDS-SEM or EPMA). The X-250 pXRF (SciAps) used in this study do not include Re in its quantification program. Moreover, the spot diameter (4 mm) is generally larger than the molybdenite size in this area. Hence, Re cannot be quantified and even if it were, the value would be that of Re in the analytical spot and not in molybdenite only. The aims of this study is to (1) directly quantify Re with the pXRF and (2) determine the concentration in Re within the molybdenite.

In Energy-dispersive XRF, there is an interference between the Zn-Kα emission line (8.6389 keV) and the Re-Lα emission line (8.6524 keV). If Zn is quantified and Re not included into the analytical program, the Re signal will be interpreted as Zn quantities. That is the case with our X-250 pXRF. In Thrace region, molybdenite occurs in quartz veins sometimes associated with few feldspar or pyrite but no Zn-bearing minerals. When measuring molybdenite-bearing veins, all the Zn quantitatively measured by the pXRF corresponds to a Re signal. That effect can be corrected by applying a correction factor on the Zn value to convert it into a Re quantity in situ by using calibration curves. A specific user method can also be easily implemented into the tool. In case Zn-bearing minerals are also found in the molybdenite-bearing veins, the in situ method requires a multilinear correction of signal obtained from the ROIs of Zn and Re. That is more difficult to implement and in the meanwhile, one can obtain signals from Zn and Re separately by proceeding to spectral decomposition using the PyMCA software (Solé et al., 2007). Once separated, these signals can be converted into concentrations of each elements with calibration curves. These curves have been built from the measurement of reference samples consisting in chosen proportions of SiO2 (considered as the matrix), MoS2, Re and Zn powders. That enabled to evaluate the impact of each parameter on detection limit, precision and accuracy of the Mo, Re and Zn concentrations. The calibration curves were tested by the use of a set of validation samples.

In our case study, Re and Mo are only within molybdenite. The quantity of Re in the analysed area is mainly induced by the quantity of molybdenite, thus Mo, in the same area. The effect of Re-enrichment in molybdenite appears as a second order phenomenon. With these developments, Re-enrichment in molybdenite becomes a mapable parameter.

How to cite: Jatteau, M., Cauzid, J., Tarantola, A., and Voudouris, P.: In situ Rhenium (Re) quantification by pXRF in Molybdenite from porphyry-epithermal deposits (Thrace, NE Greece), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12933, https://doi.org/10.5194/egusphere-egu24-12933, 2024.

    The Wenchang Formation and Enping Formation in the Pearl River Mouth Basin have huge oil and gas potential, but the migration and accumulation characteristics are not clear, which seriously restricts the large-scale exploration and development of oil and gas.In combination with thin section,scanning electron microscope and high-pressure mercury injection, physical modeling experiments of oil charging were conducted to find out laws and affecting factors of oil migration and seepage in reservoirs using core samples from reservoir beds of the Wenchang formation and Enping formation in Zhu-I Depression, Pearl River Mouth Basin. The growth curve of oil saturation presents three stages: rapid growth, slow growth and stabilization, and the final oil saturation ranges from 30% to 80%. Reservoir pore types are mainly intergranular pore, dissolution pore and fracture, and reservoir can be divided into three types: high porosity-high permeability, high porosity-low permeability and low porosity-low permeability. At the same time,The growth modes of oil saturation can also be divided into three types: Type Ⅰ is rapid speed growth-high saturation type, corresponding to high porosity-high permeability reservoir; The Type Ⅱ is medium speed growth- medium saturation type, corresponding to high porosity-low permeability reservoirs. The Type Ⅲ is slow speed growth-low saturation type, corresponding to low porosity-low permeability reservoir. The microscopic model diagram of oil charging shows that with the change of reservoir type from high porosity-high permeability to low porosity-low permeability, the main pore types of charging change from intergranular pore and dissolution pore to dissolution pore and fracture, and the growth mode of oil saturation also changes from type I to type III. The accumulation process and flow characteristics of crude oil are dominantly influenced by the injection pressure and pore structure of reservoirs.The injection pressure is a prerequisite for the increase of oil saturation,and pore structure is the main factor to control the growth pattern of oil saturation. Based on the experimental results,the relationship diagram of porosity-permeability- charging pressure-oil saturation is established. According to the distribution of residual pressure and the relationship diagram,the lower porosity-permeability limit of the reservoir to reach the specific oil saturation under different residual pressure can be determined. This is conducive to the dynamic analysis of oil and gas charging process and the prediction of oil saturation under different physical properties and dynamic conditions.

How to cite: zhao, X., liu, H., and liu, J.: Physical simulation on oil charging process and controlling factor in reservoirs of Wenchang formation and Enping formation in Zhu-I Depression, Pearl River Mouth Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13801, https://doi.org/10.5194/egusphere-egu24-13801, 2024.

EGU24-14928 | Orals | ERE4.1

Towards hyperspectral exploration vectors in the Central European Kupferschiefer district 

Moritz Kirsch, Samuel Thiele, Yuleika Madriz, Filipa Simões, Atilla Basoglu, Yonghwi Kim, and Richard Gloaguen

Europe holds significant potential for crucial metals essential for renewable energy and digital advancements. However, there is a need for a deeper understanding of the European subsurface, coupled with a requirement to reduce the environmental impact of exploration activities. We employ hyperspectral scanning of legacy drill cores to develop innovative indicators of mineralization in the Central European Kupferschiefer district, home to Europe's largest copper and silver resources. Hyperspectral imaging, capturing spectral reflectance and emission across numerous spectral bands, allows for non-invasive, high-resolution mineral mapping of drill cores. Initial findings showcased the technique's ability to identify critical redox boundaries and alteration minerals, aiding ore deposit characterization. In the framework of two research projects, we scanned 2400 meters of drill core from 87 boreholes across the Spremberg–Graustein Kupferschiefer deposit in Germany. For data acquisition, we deployed a drill-core scanner with a full suite of hyperspectral sensors covering the visible and near-infrared (400 to 970 nm), shortwave (970 to 2500 nm), mid-wave (2700 to 5300 nm), and longwave infrared (7700 to 12300 nm) ranges. The collected data were processed through a novel, open-source software pipeline, which enables i) real-time correction, processing, and analysis, ii) efficient data management and storage, and iii) comprehensive visualization and integrative interpretation of the hyperspectral drill core data. We upscaled mineral abundances across all of the scanned drill cores using a supervised learning model trained on quantitative mineralogical data from select samples. Initial analyses, particularly the visual alignment of hyperspectral derivatives at the base of the Kupferschiefer marker horizon, indicate geographical patterns in dolomite content and correlations between carbonate, clay, and mica compositions and copper grade. The hyperspectral data will eventually be integrated with geological, geophysical, and geochemical constraints to create accurate 3D subsurface and 4D mineral system models, aimed at enhancing our understanding of geological processes and resource management strategies in similar geological settings worldwide.

 

Acknowledgements: This research has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement nº 101058483 (VECTOR), and from the Geological Survey of Saxony (Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie, LfULG) under agreement nº 4-0912014LFULG01-88.

How to cite: Kirsch, M., Thiele, S., Madriz, Y., Simões, F., Basoglu, A., Kim, Y., and Gloaguen, R.: Towards hyperspectral exploration vectors in the Central European Kupferschiefer district, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14928, https://doi.org/10.5194/egusphere-egu24-14928, 2024.

EGU24-15110 | ECS | Posters on site | ERE4.1

Big data techniques for real-time hyperspectral core logging 

Samuel Thiele, Moritz Kirsch, Sandra Lorenz, and Richard Gloaguen

Hyperspectral imaging is gaining widespread use in the resource sector, with applications in mineral exploration, geometallurgy, and mine mapping. However, the sheer size of many hyperspectral datasets (>1 Tb), and associated data correction and analysis challenges, limit the integration of this technique into time-critical exploration and mining workflows. We present an overview of several newly developed  real-time processing capabilities to mitigate these challenges, and so provide hyperspectral data and derived products (e.g., mineral abundance estimates) in near real-time. This allows for efficient, timely, and automated delivery of hyperspectral data to enhance geological activities.

Hyperspectral data generally needs to be corrected, coregistered, cropped and masked, before derivative results can be generated, visualized and stored. To achieve real-time processing, each of these steps, which can involve the computationally intense manipulation of several Gb worth of spectral data, need to be completed within the 1-3 minutes a typical instrument or scanner takes to capture a data cube. To help with this, we have developed a python-based asynchronous processing pipeline, crunchy, that uses a file-discovery-based triggering mechanism to spawn parallel processing workflows that automatically perform these tasks. Coregistered and radiometrically corrected results are then stored using a directory-based data structure managed by a second python utility, hycore, that facilitates (1) consistent data storage, (2) file-based out-of-core processing, and (3) management of the various metadata required to localize and give meaning to hyperspectral drill core data. We have also developed a third python tool, hywiz, to enable an easy browser-based interaction with hycore databases. This includes the visualisation of sensor results and analysis products for individual trays and drillhole mosaics. Additional data such as assays, logging notes or downhole geophysical data can be overlain on these to enable integrated interpretation of otherwise disparate datasets. 

We hope that these tools will enable greater use of hyperspectral data in research and industry, and facilitate e.g., hyperspectrally enhanced core-logging, sample selection, vectoring and, potentially, realize self-updating 3-D geological models.

How to cite: Thiele, S., Kirsch, M., Lorenz, S., and Gloaguen, R.: Big data techniques for real-time hyperspectral core logging, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15110, https://doi.org/10.5194/egusphere-egu24-15110, 2024.

EGU24-15719 | Orals | ERE4.1

Challenges of in-line, sensor-based characterisation of recycling streams 

Margret Christine Fuchs, Sandra Lorenz, Yuleika Carolina Madriz Diaz, Andrea de Lima Ribeiro, Elias Arbash, Jan Beyer, Christian Röder, Nadine Schüler, Kay Dornich, Johannes Heitmann, and Richard Gloaguen

Optical sensors are a key enabler for an in-line, real-time characterisation, quality control and monitoring in industrial, conveyor-based raw material processing. Innovators are actively exploring non-invasive optical sensing to solve current problems in economic, socially acceptable and ecologic resource handling with high efficiency. Despite the evident advantages, integrating available optical technologies into sensor systems poses various challenges. A detailed understanding of physical parameters as well as smart solutions are required to mitigate or circumvent some of the limitations. Realistic solutions for the industry rely on understanding what is possible, where are the key limiting factors and which of the challenges can be overcome in the future.

In this contribution, we present four examples from our HELIOS lab research projects in the field of recycling of society-relevant material streams to discuss the major challenges. Our focus lies on the suitability of optical sensor systems for industrial applications. We emphasize the pathways from scientific setups to industrial demonstrators and highlight the relevant parameters, when operating sensors such as RGB, hyperspectral reflectance imaging (HSI), laser-induced fluorescence (LiF) together with Raman scattering, x-ray fluorescence (XRF) and laser-induced breakdown spectroscopy (LIBS).  

Extremely relevant to the industry is speed (or material throughput). Common conveyor belt speeds of several meters per second imply low signal integration times for the optical sensors (or high frame rates in the case of cameras). While industrial high-speed RGB cameras are well suitable, HSI cameras rely on longer integration times to collect signals with adequate intensities across hundreds of detection bands. Current HSI technology is successful in a variety of conveyor belt applications (2D dynamic setup) at a few meters per second, however, a transfer to applications for material detection in air flows (3D dynamic setup) outlines the trade-off between signal quality and acquisition speed. Similarly, signals of very low intensities as seen in laser-induced fluorescence hyperspectral scanning highlight the multi-parameter trade-off between integration times, acquisition speed and excitation power, where the latter is largely dependent on available optical components.

Most of our consumer products are not made of pristine, pure material but come with coating, as compounds and/or with additives to improve appearance and performance of the materials. For recycling, this poses significant challenges for material separation and processing. Using optical sensors in recycling operations then often implies extrapolating the surface properties as representative of the actual material. We demonstrate with examples from several projects, how coating and additives affect the spectral signatures in polymers (esp. black polymers) and metals (steel and aluminum), and how a combination with additional validation sensors (e.g. Raman, LIBS) can provide important information in materials. This information is essential for an adequate and high-quality recycling process.

The given examples and related research are based on collaborations with the industry and aim at developing and testing new concepts and evaluating corresponding tools for data acquisition and real-time processing in recycling facilities. We gratefully acknowledge project funding for RAMSES-4-CE (KIC RM 19262), Digisort (03XP0337B), Car2Car (19S22007B) and FINEST (KA2-HSC-10).

How to cite: Fuchs, M. C., Lorenz, S., Madriz Diaz, Y. C., de Lima Ribeiro, A., Arbash, E., Beyer, J., Röder, C., Schüler, N., Dornich, K., Heitmann, J., and Gloaguen, R.: Challenges of in-line, sensor-based characterisation of recycling streams, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15719, https://doi.org/10.5194/egusphere-egu24-15719, 2024.

EGU24-15856 | ECS | Orals | ERE4.1

Unveiling the temporal dynamics: A spatiotemporal prospectivity model for porphyry systems in Papua New Guinea and the Solomon Islands 

Ehsan Farahbakhsh, Sabin Zahirovic, Brent I. A. McInnes, Sara Polanco, Fabian Kohlmann, Maria Seton, and R. Dietmar Muller

The tectonic setting of porphyry systems is influenced by the subduction style and history that impact the distribution and concentration of copper (Cu), gold (Au), and molybdenum mineralisation. Typically linked to the intrusion of arc-related magma into the upper crust along subduction zones, the formation of porphyry ore deposits is currently understood primarily through geological and geophysical observations of the overriding plate, creating a knowledge gap regarding arc metallogenic processes in convergence zones over time. In this study, we address this gap by investigating the connection between the formation of porphyry Cu-Au deposits and the evolution of subduction zones, utilising a range of features derived from a plate motion model and oceanic crust age grids. Incorporating 47 Cenozoic intrusion-related Cu-Au deposits located in Papua New Guinea and the Solomon Islands, we employ a spatiotemporal mineral prospectivity framework that leverages advanced machine learning methods to map prospective arc terranes. The model successfully predicts all known mineral occurrences in the testing set and identifies the most important features for predicting potential areas of porphyry mineralisation.
We observe that the obliquity angle of the relative motion vector in subduction zones plays a crucial role in distinguishing between mineralised (highly prospective) and barren areas (low prospective). This feature is recognised for its significant influence on a spectrum of geological processes, encompassing fluid flow dynamics, magmatic processes, and stress regimes. This influence extends to the transport of mineralising elements and the creation of favourable conditions for ore deposition, with the range of 25 to 90 degrees correlating with mineralised zones, suggesting that oblique subduction zones are more likely to be rich in mineralisation in the study area. Additionally, the length and curvature of arcs emerge as important features for identifying mineralised areas, with tightly curved arcs associated with higher compressional stress and fractures facilitating magma ascent and porphyry formation. The orthogonal component of the downgoing absolute plate velocity is also identified as a significant feature, with higher magnitudes associated with mineralisation, indicating that rapid convergence rates are optimal for porphyry system formation due to accelerated metasomatism and partial melting processes in the overriding plate.
The seafloor spreading rate of the subducting crust, computed at the time when the crust originally formed, is an additional important feature linked to mineralised areas. This preferentially occurs when crust formed in the range of 25 to 55 mm/yr (half spreading rate) is subducted. At lower spreading rates, there is a higher proportion of serpentinised mantle peridotite, adding water and carbon to the plate, which will be expelled during subduction, contributing to increasing hydrous melting in the mantle wedge and acting as a catalyst for porphyry deposits. In conclusion, the performance of our model underscores the potential of integrating plate motion models and machine learning to advance mineral exploration along subduction zones. This approach holds promise for more efficient, accurate, and sustainable exploration strategies in these geologically active areas.

How to cite: Farahbakhsh, E., Zahirovic, S., McInnes, B. I. A., Polanco, S., Kohlmann, F., Seton, M., and Muller, R. D.: Unveiling the temporal dynamics: A spatiotemporal prospectivity model for porphyry systems in Papua New Guinea and the Solomon Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15856, https://doi.org/10.5194/egusphere-egu24-15856, 2024.

EGU24-16838 | Posters on site | ERE4.1

VNIR-SWIR spectral signatures of the Cu-Co-Ni mineralization and the host rocks of El Aramo (Asturias, España). 

Mercedes Suarez, José Daniel Ramírez, Ángel Santamaría, and Juan Morales

The mineralization of the Aramo Plateau is a carbonate-hosted deposit with major Cu-Co-Ni sulphides and arsenides and minor precious metals. There are a few studies on the deposit, but according to Paniagua et al., (1988), it is an epithermal mineralization with an evolutive sequence involving temperatures from 85ºC to 170ºC whose hydrothermal systems were related to the distensive Late-Variscan tectonic activity in the region. Weathering and oxidation of primary sulfides in ore and waste rock materials has resulted in the formation of secondary minerals such as goethite, hematite, malachite, azurite, and others, causing the release of elements, such as Cu or As, to soils, waters or stream sediments (Loredo et al., 2008).

This study is a part of the S34I project (Secure and Sustainable Supply of raw materials for EU Industry) which research and innovate new data-driven methods to analyze Earth Observation data, supporting systematic mineral exploration and continuous monitoring of extraction activities with the aim to increase European autonomy regarding raw materials. This work shows the preliminary results of a study conducted by X-ray diffraction and field VNIR-SWIR spectroscopy related to 1) the identification the mineralogical composition of a very wide group of representative samples from old mines in the area and from the surface of the Aramo Plateau, both outcropping rocks and soils; 2) the spectral response in the VNIR-SWIR wavelength range (the same range that hyperspectral remote sensors use); and 3) the determination of the spectral signatures of the different paragenesis of the mineralization, the host rocks and the soils in which supergenic processes could occur.

Financial support by S34I project (DOI: 10.3030/101091616) is acknowledged.

How to cite: Suarez, M., Ramírez, J. D., Santamaría, Á., and Morales, J.: VNIR-SWIR spectral signatures of the Cu-Co-Ni mineralization and the host rocks of El Aramo (Asturias, España)., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16838, https://doi.org/10.5194/egusphere-egu24-16838, 2024.

EGU24-17303 | Orals | ERE4.1 | Highlight

First results from the SEEMS DEEP seismic survey conducted over the Koillismaa Igneous Complex, Northern Finland 

Brij Singh, Yousef Amirzadeh, Uula Autio, Andrzej Gόrszczyk, Suvi Heinonen, Michał Malinowski, and Marek Wojdyła and the SEEMS DEEP Working Group

The Koillismaa layered igneous complex (KLIC) in northern Finland spans a large distance from the Finnish-Swedish border to the Finnish-Russian border. It has been an area of interest for several decades among geologists due to its potential to host several critical raw materials including cobalt & nickel which are key materials required for lithium-ion batteries. The KLIC intrusion comprises outcropping Koillismaa and Näränkävaara layered complex mafic-ultramafic intrusions that are interestingly connected by a zone of high gravity and magnetic anomalies. Extensive petrophysical and lab studies were conducted by the Geological Survey of Finland on a 1.7 km long deep drillhole located within the area of our interest. A pre-existing low-fold seismic study indicated the reflectivity of the ultramafic rocks. Drillhole study further established the fact that the contacts with mafic intrusion rocks having the potential to host mineralization are causing observable seismic reflections at 1.4 km depth. The ongoing SEEMS DEEP project (2022-2025), an ERA-MIN 3 sponsored project comprises an integrated approach of using seismics and electromagnetics studies to substantially improve the geomodel of the Koillismaa area which will help in better decisions in exploration drilling. In this study, we are focussing on the seismic part of the project. In August 2023, an irregular-sparse 3D seismic and two regional 2D seismic lines, roughly in the direction of E-W and NNE-SSW were acquired under the SEEMS DEEP project. The overall aim of the 2D seismic lines was to constrain large-scale information about the geological architecture of the study area, whereas the 3D survey was conducted to highlight the detailed information from the rock volumes near the deep drill hole. The acquired data, both 2D (~10 Km and ~12 Km) and 3D (~5 Km x 6 Km), are of good quality with reflections visible in the raw data. An 8-tonne Mark IV Vibroseis truck was used as a seismic source for both surveys, with sweep frequency ending at 160 Hz. Almost 3000 single-component receivers (Strydes) were deployed in varying subarctic terrains defined by swamps and forests for the 3D survey. For 2D profiles, over 700 three-component receivers (GSBs) were used next to the existing gravel roads utilized by the Vibroseis truck. For the 3D survey, receiver spacing was kept at 30 m with inline spacing of 200 m. Shot points were located mainly following the existing roads within the forest. For the 2D survey, a uniform receiver spacing of 15 m and a shot spacing of 30 m was used. Seismic data processing was applied with the overall aim of suppressing noise, boosting signal-to-noise ratio, and improving reflectivity in the data. Special emphasis was put on handling the highly heterogeneous near-surface weathering layer. Final results revealed several reflectors at various depths, which have preliminarily been interpreted to originate from mafic intrusions, diabase veins, and faults cross-cutting the intrusion.

How to cite: Singh, B., Amirzadeh, Y., Autio, U., Gόrszczyk, A., Heinonen, S., Malinowski, M., and Wojdyła, M. and the SEEMS DEEP Working Group: First results from the SEEMS DEEP seismic survey conducted over the Koillismaa Igneous Complex, Northern Finland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17303, https://doi.org/10.5194/egusphere-egu24-17303, 2024.

EGU24-19207 | ECS | Orals | ERE4.1 | Highlight

The Horizon Europe AGEMERA Project: Innovative Non-Invasive Geophysical Methodologies for Mineral Exploration 

Jari Joutsenvaara, Marko Holma, Pasi Kuusiniemi, Markku Pirttijärvi, Barbara Stimac Tumara, Martin Schimmel, and David Martin

The AGEMERA project [1], which is an acronym for Agile Exploration and Geo-Modelling for European Critical Raw Materials, employs three non-invasive survey methods for mineral exploration: a passive seismic method to assess bedrock hardness and rock type boundaries; an integrated, multi-sensing fixed-wing drone system for measuring conductivity, magnetism, and radioactivity; and a multidetector system based on muon detection for detailed 2D, 3D, and 4D density profiles of large-volume rock bodies (with the 4th dimension being time). The technologies are designed to map geological structures in scenarios where traditional methods are either environmentally unsound or socially challenging. By the project's conclusion, these methods are anticipated to achieve a Technological Readiness Level (TRL) of 5 within a three-year timeline.

The technologies vary in their operational capacities, including acquisition time, depth penetration, area coverage, and volume assessment. The multi-sensing drone effectively probes to 300-500 meter depth and can survey vast areas, up to hundreds of square kilometres, in a single campaign. Muography, on the other hand, can reach depths of up to 1000 metres and cover large volumes, up to a cubic kilometre. Passive seismic analysis, meanwhile, can survey any area and depth while a larger depth usually implies a lower resolution. While these techniques, especially when combined with deep 3D muography, may require extended periods for data collection, the valuable insights they offer make them a worthwhile investment.

After conducting these innovative, non-invasive geophysical surveys, the findings will be consolidated in a web-based data repository. This repository will be accessible for in-depth analysis to enhance our understanding of critical raw material distribution.

The project receives funding from the Horizon Europe program (Grant agreement ID: 101058178).

 

[1] AGEMERA project homepage, www.agemera.eu (accessed 9.1.2024)

How to cite: Joutsenvaara, J., Holma, M., Kuusiniemi, P., Pirttijärvi, M., Stimac Tumara, B., Schimmel, M., and Martin, D.: The Horizon Europe AGEMERA Project: Innovative Non-Invasive Geophysical Methodologies for Mineral Exploration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19207, https://doi.org/10.5194/egusphere-egu24-19207, 2024.

EGU24-20261 | ECS | Orals | ERE4.1

REE (re)cycle: a multi-sensor investigation from rocks to tailings 

Andréa de Lima Ribeiro, Titus Abend, Margret Fuchs, Christian Röder, Jan Beyer, Kimmo Kärenlampi, Yang Xiao Sheng, Johannes Heitmann, and Richard Gloaguen

Rare earth elements (REE) are key constituents in electronic devices (e.g. smartphones, batteries), being present in both end-user and industrial applications. The rapid innovation cycles of electronic devices, combined with the increasing demand for new technological applications (e.g. mobility and e-cars) pose a challenge for the supply of REE, which are considered as Critical Raw Materials (CRM). This scenario calls for rapid, non-invasive methods that enable the identification of new REE-rich mining resources. Furthermore, the high supply risks associated with CRM such as REE drive technological developments to compensate and overcome market fluctuations by turning previously not mined co-resources into valuable and economic modalities, such as re-mining materials.

We present an investigation focused on the identification of REE in waste rocks and tailing materials from the mine of Siilinjärvi (Finland). The deposit in the area consists of alkaline-carbonatite rocks, with the most important REE-bearing minerals being apatite (average REE concentration: 0.4% (wt%)) and monazite (REE concentration: up to 67% (wt%)). Mining activities focus on extraction of phosphate from fluorapatite, and the chemical reactions involved in this extraction generate phosphogypsum (PG) as a by-product. Literature reports indicate that REE can be incorporated to the PG matrix in the crystallisation process, with the most relevant examples including Nd, Ce, La, Sm, Gd, Tb, Dy, and Eu. 

Our goal is to highlight how the sequential acquisition by multiple optical methods (multi-sensor approach) can trace REE contents for individually identified REE from pristine rocks to processing waste dumped in tailings. Each material type was scanned by two fast hyperspectral imaging (HSI) sensors integrated in a conveyor-belt system:  a reflectance-based HSI sensor operating in the visible to near-infrared and short-wave infrared (Specim AisaFenix); and an innovative laser-induced fluorescence line scan sensor (HSI-LiF, Freiberg Instruments). The optical sensing results were validated by mineralogical methods (mineral liberation analysis (MLA)). MLA results for PG indicate the presence of REE-bearing minerals including gypsum, apatite, and monazite (respective abundances (wt%): 97.4, 0.6, and 0.08).

Optical features characteristic of Nd were identified on rocks and tailings samples by both HSI-reflectance and HSI-LiF sensors. Spectral signatures were detected in HSI-LiF spectra for an additional REE group including Sm, Er, and Pm.

We highlight that efficient, non-invasive optical sensing can detect and re-evaluate tailing materials as a baseline for economic considerations according to market needs. The results confirm that REE detected on the pristine rocks of the mine can be traced through the mineral processing route to be found again in the tailings material. The multi-sensor optical detection based on HSI-reflectance and HSI-LiF, accordingly, provides an efficient non-invasive tool for exploring both mining and re-mining potential by providing immediate results on REE types and their spatial abundance, when employed as scanning techniques.

This investigation was performed within the scope of EIT-funded projects (inSPECTOR and RAMSES-4-CE).

How to cite: de Lima Ribeiro, A., Abend, T., Fuchs, M., Röder, C., Beyer, J., Kärenlampi, K., Xiao Sheng, Y., Heitmann, J., and Gloaguen, R.: REE (re)cycle: a multi-sensor investigation from rocks to tailings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20261, https://doi.org/10.5194/egusphere-egu24-20261, 2024.

EGU24-21098 | ECS | Posters on site | ERE4.1

Impact of using a 3.5 μm film to analyze the chemical composition of crystal samples with a handheld X-Ray Fluorescence equipment 

Filipa Dias, Ricardo Ribeiro, Alexandre Lima, Filipe Gonçalves, Encarnación Roda-Robles, and Tânia Martins

Some potassium-feldspar crystals from lithium-rich aplite-pegmatites from Northern Portugal have been analyzed with a handheld X-Ray-Fluorescence (XRF) equipment. This study compares the impact of analyzing the samples with an XRF film versus analyzing them without it. The film used was a Hitachi Poly-S High Performance XRF Sample Film of 3.5 μm, commonly used for analyzing samples in cups and powders. Although Hitachi alerts for the unsuitability of the film for analyzing light elements, this study helps understand the extent of error that this film can cause when analyzing this type of sample. 15 cleaned potassium feldspar crystals with a size between 1-3 cm have been analyzed with a Bruker S1 TITAN 600 containing an X-ray tube with a 2 W and 5-100 μA Rh anode. The Geomining factory calibration was used for the sample analysis.

The results show that the potassium-feldspars analyzed with the film had their major elements drop by 20-40% for silica (SiO2), 30-50% for aluminum (Al2O3) and 10-20% for potassium (K2O). As for the trace elements, calcium (Ca) dropped by 20-30%, phosphorous (P) by 20-40% and rubidium (Rb) and iron (Fe) have small errors that can vary from plus 0-10% to minus 0-10%. Knowing the film impact will hopefully be of assistance for the correct interpretation of portable XRF results during field campaigns for mineral exploration.

This study was financially supported by FCT, I.P., in the framework of the ICT (UIDB/04683/2020 and UIDP/04683/2020), by the PhD project (2020.05534.BD) and by national funds from MCTES, through FCT, co-financed by ESF through POCH and NORTE 2020. This work is also supported by the Greenpeg project, reference 869274, funded by the Horizon 2020 framework program of the European Union.

How to cite: Dias, F., Ribeiro, R., Lima, A., Gonçalves, F., Roda-Robles, E., and Martins, T.: Impact of using a 3.5 μm film to analyze the chemical composition of crystal samples with a handheld X-Ray Fluorescence equipment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21098, https://doi.org/10.5194/egusphere-egu24-21098, 2024.

EGU24-21276 | Orals | ERE4.1

Application of innovative technologies for increasing gold production in Kyzylkum province of Uzbekistan 

Alexander Antonov, Vladimir Tsoy, and Bakhtiyar Nurtaev

The Kyzylkum province in Southern Tien Shan, Uzbekistan, which includes the world's largest gold deposit Muruntau, is among the world's major gold provinces. Analysis of all available geological and geophysical data has revealed ten linear trends controlled by regional strike-slip shear zones in the ore-bearing sand-shale sediments O₂-S₁. Analogies were made with gold trends in North-Eastern Nevada (Carlin trend and others). Gold is present predominantly as microinclusions in pyrite and arsenopyrite in both provinces. A significant part of inclusions is represented by invisible nano-sized gold particles.

Opportunities of increasing gold output in the Kyzylkum province are connected with the reduction of losses of "invisible" gold in the process of ore concentration and processing. Innovative technologies and modern laboratory equipment were used to determine nano-sized gold concentration. Another source of increasing gold production is exploration and development of ore-controlling structures overlapped by younger sediments. Remote sensing methods are widely used to identify promising parts of the structures.

 

How to cite: Antonov, A., Tsoy, V., and Nurtaev, B.: Application of innovative technologies for increasing gold production in Kyzylkum province of Uzbekistan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21276, https://doi.org/10.5194/egusphere-egu24-21276, 2024.

EGU24-2426 | ECS | Posters virtual | ERE4.3

Early Diagenesis In Carbonate Sediments 

KaiQi Sheng

Extensive lacustrine carbonate-rich shale intervals including upper fourth member (Es4s shale) and lower third member (Es3x shale) of the Paleogene Shahejie Formation have been deposited in the Boxing Sag, Dongying depression, Bohai Bay Basin, East China. These two representative shale members are considered to be good exploration prospects in the study area. In order to clarify the diagenetic process and exploration significance of sparry calcite in lacustrine calcareous shales, we take calcareous shale in Es4s to Es3x members in Boxing Sag as the research object, By means of thin section identification method, EDS line scan, Scanning Electron Microscopy, Fluid Inclusion Analysis, carbon and oxygen isotope and other methods, sparry calcite is classified, and then the genesis and diagenetic fluid of various types of sparry calcite are studied, so as to clarify the formation mechanism of sparry calcite, and finally discuss the influence of sparry calcite on reservoir. Finally, the influence of sparry calcite on the development of reservoir pores was discussed. The results show that the types of sparry calcite in the study area include granular calcite, porphyritic calcite and fibrous calcite, which are mainly caused by biological oxidation and thermal evolution of organic matter. Biogenic calcite has the characteristics of rich Mg and δ13C, and the organic matter makes the crystal more enriched with Fe and deficient δ13C. The formation of three kinds of sparry calcite has different effects on pore development, which is probably beneficial to improve reservoir physical properties.

How to cite: Sheng, K.: Early Diagenesis In Carbonate Sediments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2426, https://doi.org/10.5194/egusphere-egu24-2426, 2024.

There are two sets of petroliferous strata developed in the Huoshiling Formation volcano in the Longfengshan area of the Changling fault Depression. The oil and gas have the characteristics of "near source gas, far source oil rich", the abundance of oil and gas decreases from the depression zone to the western tectonic belt, and is enriched in the top and middle of volcanic rocks in longitudinal direction, and widely distributed along faults in plane. In this paper, the controlling factors of hydrocarbon distribution in volcanic rocks are discussed from the perspectives of source rock development condition, reservoir physical property and transport condition by means of seismic, well logging and geochemical data, cores and microsections observation, CT scanning and inclusion analysis. The results show that the oil and gas distribution in the volcanic rock mass in Longfengshan area is mainly affected by the following factors: the thermal evolution degree of the source rock controls the oil and gas phase distribution, and the source and reservoir configuration determines the oil and gas capture probability; The distribution characteristics of high-quality volcanic rock reservoir can control the distribution range of oil and gas, and the vertical development difference of primary, secondary dissolution and fracture high-quality reservoirs determines the vertical accumulation of oil and gas. The fault and unconformity control the migration of oil and gas from the depression zone to the slope zone and the western tectonic zone, and its transport performance and the micro-transport structure of internal fractures ultimately determine the location of oil and gas accumulation. The distribution of overlying layers in and above volcanic rocks, the type of reservoir-cap combination and the configuration of broken cap prevent the oil and gas loss and control the oil and gas enrichment horizon. Based on the differences of main controlling factors of hydrocarbon accumulation in volcanic rocks, the effective source rock thickness, volcanic reservoir physical properties, reservoir-cap combination characteristics and transport conditions are taken as indicators to evaluate the hydrocarbon charging capacity of volcanic rocks, and the measured values of the above factors are divided into several intervals. According to the distribution range of the evaluation index, each interval is evaluated. Finally, according to the calculation results of the established oil and gas charging capacity evaluation formula, the evaluation results have a good correspondence with the current oil and gas distribution, and the results have certain guiding significance for determining the direction of oil and gas exploration in the later period.

How to cite: Hou, S. and Jiang, Y.: Main controlling factors of volcanic oil and gas distribution and charging capacity evaluation of Huoshiling Formation in Longfengshan area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4824, https://doi.org/10.5194/egusphere-egu24-4824, 2024.

EGU24-4835 | ECS | Orals | ERE4.3 | Highlight

Subducting seafloor anomalies promote porphyry copper emplacement 

Ben Mather, Dietmar Müller, Christopher Alfonso, Nicky Wright, and Maria Seton

The oceanic seafloor is scarred by fracture zones, seamounts, and large igneous provinces (LIPs) which record tectonic deformation and plume impingement through deep time. The subduction of these seafloor anomalies has been speculated to localise slab tearing, enrich the mantle wedge in volatile elements, or trigger flat slab subduction. However, the association between these subducting seafloor anomalies and the emplacement of mineral deposits in the overriding plate is poorly understood. Using a tectonic plate reconstruction of the last 170 million years paired with a machine learning model trained on the location and age of known porphyry copper deposits, we find that the subduction of seafloor anomalies is highly predictive of mineral emplacement, particularly along the American Cordillera. The subduction of fracture zones and seamounts are consistently within the top 10 highest ranked features after the crustal thickness of the overriding plate and the plate convergence velocity. We propose that fracture zones, seamounts, and LIPs have higher degrees of hydrothermal alternation and serpentinization compared to regular seafloor which oxygenates the sub-arc mantle upon their subduction, leading to more fertile conditions for porphyry copper emplacement in the overriding plate. These findings have significant implications for the discovery of new porphyry copper deposits to power the renewable energy transition.

How to cite: Mather, B., Müller, D., Alfonso, C., Wright, N., and Seton, M.: Subducting seafloor anomalies promote porphyry copper emplacement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4835, https://doi.org/10.5194/egusphere-egu24-4835, 2024.

EGU24-5899 | ECS | Orals | ERE4.3

Geothermal Heat Flow Mapping of Germany: Multi-Geophysical and Geological Data Inversion and Associated Uncertainties 

Mohamed Sobh, Rodolfo Christiansen, Magued Al-Aghbary, and Gerald Gabriel

In geothermal resource assessment, terrestrial heat flow is a crucial metric, providing key insights into lithospheric thermal states and energy balance, with significant implications for geology, geophysics, and geodynamics. This study focuses on modeling geothermal heat flow (GHF) in Germany, where direct borehole temperature gradient data is limited, i.e. only 595 unevenly distributed published heat flow points exist.

To address this data scarcity, our approach utilizes indirect methodologies for GHF estimation. We integrate various geophysical and geological datasets, including gravity, magnetics, upper mantle velocity structure, topography, crustal and lithospheric thickness, fault distribution, proximity to volcanoes, and compositional data. This multi-faceted approach allows us to overcome the spatial constraints inherent in single-data reliance and more accurately reconstruct measured heat flow, e.g. in comparison to classical curie depth estimations.

Given the complexities in direct geophysical and geological data representation, our project utilizes a probabilistic, multi-geophysical inversion method. This not only enhances our understanding of Germany's geothermal potential but also allows for a detailed quantification of uncertainties.

We have developed a new heat flow map with a high resolution. This map more accurately and effectively illustrates the terrestrial heat flow distribution in the study area, providing a more detailed depiction than previous interpolation results. Our preliminary results have successfully identified high heat flow zones in regions such as the Rhenish Massif, Molasse Basin, and Upper Rhine Graben.

How to cite: Sobh, M., Christiansen, R., Al-Aghbary, M., and Gabriel, G.: Geothermal Heat Flow Mapping of Germany: Multi-Geophysical and Geological Data Inversion and Associated Uncertainties, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5899, https://doi.org/10.5194/egusphere-egu24-5899, 2024.

As many critical metals are initially locked up in the volatile-bearing mantle, the first critical stage to any mineralizing process requires their liberation by partial melting of the mantle source, followed by the onset of an effective upward transport mechanism into the overlying crust. The initial melts of volatile-bearing mantle lithologies are incipient melts rich in volatile and incompatible components, which are effective transport agents at low mantle temperatures. This means that understanding the formation, composition, and migration of these melts is crucial to constraining metal transport in the mantle.

The incipient melts of peridotite usually solidify in the mantle to form dykes rich in hydrous minerals such as amphibole and mica. These assemblages commonly also contan abundant clinopyroxene and are known as “hydrous pyroxenites”, and may also contain several other accessory phases including apatite, ilmenite, and rutile.  We have recently gained abundant experimental information on the melting conditions and compositions of these hydrous pyroxenites, which can be viewed as second-stage melts. Although volumetrically minor in the lithosphere as a whole, these hydrous pyroxenites all produce melts at lower temperatures than peridotite, rapidly exhausting hydrous minerals such as amphibole, which have been discovered to host large concentrations of critical metals  [1].

Our results for trace element analyses of melts and residual minerals indicate that hydrous minerals such as phlogopite, amphiboles and apatite all have high partition coefficients for Ni (3-20) and other transition elements, meaning that the formation of hydrous pyroxenites during first-stage melting processes may lead to the formation of important repositories for Ni in the mantle sources of igneous rocks. The contribution of hydrous pyroxenites to the metal endowment of mantle melts may have been underestimated or overlooked in the past [1] due to the traditional association of magmatic Ni-sulfide ore deposits with basaltic to komatiitic rocks that originate by partial melting of uniform four-phase peridotite. The lower melting temperatures of hydrous pyroxenites (≈300˚C less than dry peridotite) also means that the generation of magmatic ore deposits may not require a major thermal perturbation such as a plume. Hydrous pyroxenites are commonly associated with continental regions, where their melting may be accentuated by erosion by edge-driven convection [2] or lateral advection of solids [3] at craton edges, thus explaining the association of both volatile-rich magmatism [4] and metal deposits [5] with craton edges. Thus, predictive exploration models should consider domains of the lithospheric mantle where hydrous pyroxenites may be localised and concentrated, as they may have been episodically melted throughout the long-lived geological evolution of cratonic blocks.

[1] Ezad IS et al. (2024) Mineralium Deposita. doi: 10.1007/s00126-023-01238.

[2] Davies DR and Rawlinson N (2014) Geology 42, 1031-1034.

[3] Muirhead JD et al. (2020) Nature 582, 67-72.

[4] Foley SF and Fischer TP (2017) Nature Geoscience 10, 897-902.

[5] Hoggard MJ et al. (2020) Nature Geoscience 13, 504-510.

How to cite: Foley, S., Ezad, I., and Fiorentini, M.: Metal endowment at craton edges controlled by amphibole-rich pyroxenites dykes and incipient melts in the mantle, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6806, https://doi.org/10.5194/egusphere-egu24-6806, 2024.

Natural hydrogen, emerging as a clean and abundant energy source, holds significant promise for advancing sustainable energy solutions. Its production offers a carbon-neutral alternative to fossil fuels, aligning with global efforts to mitigate climate change. This research focuses on developing a methodology to estimate the rates of natural hydrogen generation in serpentinization areas; in this case a local area in Eastern Morocco. It employs a multilevel approach that encompasses the modeling and analysis of the surface, near-surface, and deep components of the natural hydrogen system. At the surface level, potential hydrogen seeps are identified as semi-circular structures and surface faults are examined using high-resolution geophysical data. For the near-surface component or seal of the potential reservoir, which can extend thousands of meters deep, a full 3D geological model is constructed. The deep component, representing the source rock, is analyzed through the inversion of potential field data. These inversion results allow estimating the degree of serpentinization of the rocks, their volumes, and the affected surfaces. Subsequently, these volumes of rock are compared with temperature estimates to determine which part of the rock is capable of generating hydrogen. Laboratory-based hydrogen generation values from rock samples are then scaled up to the model, facilitating the calculation of hydrogen generation rates from the detected ultramafic rocks.

How to cite: Christiansen, R., Sobh, M., and Gabriel, G.: Assessing Natural Hydrogen Generation in Serpentinization Environments: A Workflow Based on a Comprehensive Case Study Analysis from the HyAfrica Project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7674, https://doi.org/10.5194/egusphere-egu24-7674, 2024.

EGU24-7867 | ECS | Orals | ERE4.3

Rift-inversion orogens are the place to be for natural hydrogen gas (H2) exploration 

Frank Zwaan, Sascha Brune, Anne Glerum, Dylan A. Vasey, John Naliboff, Gianreto Manatschal, and Eric C. Gaucher

Naturally occurring hydrogen gas (H2) represents a potentially major source of clean energy. It has been relatively overlooked so far but has gained more attention recently. The most promising mechanism for large-scale generation of such natural H2 is the serpentinization of mantle material as it reacts with water while it is brought into the “serpentinization window” (i.e., T = 200-350˚C) during mantle exhumation. We study such serpentinization-related natural H2 generation during rifting and subsequent rift inversion by means of numerical geodynamic models. In these numerical models we trace how, when, and where mantle material enters the serpentinization window, as well as when active, large-scale faults penetrate exhumed mantle bodies allowing for water circulation and serpentinization to occur.

Although serpentinization-related natural H2 generation is a phenomenon best known from magma-poor rifted margins and slow spreading ridges, we find that volumes of natural H2 generated during inversion may be up to 20 times higher than during rifting, due to the colder thermal regime in rift-inversion orogenic environments. Moreover, suitable reservoirs and seals required for natural H2 accumulation are readily available in rift-inversion orogens, whereas they may not be present when serpentinization occurs in rift or drift settings. Our model results thus provide a first-order motivation to turn to rift-inversion orogens, rather than rifts and rifted margins, for natural H2 exploration. These model-derived insights are supported by indications of natural H2 generation in rift-inversion orogens such as the Western Alps, Pyrenees, and Caucasus.

How to cite: Zwaan, F., Brune, S., Glerum, A., Vasey, D. A., Naliboff, J., Manatschal, G., and Gaucher, E. C.: Rift-inversion orogens are the place to be for natural hydrogen gas (H2) exploration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7867, https://doi.org/10.5194/egusphere-egu24-7867, 2024.

EGU24-7869 | Posters on site | ERE4.3

Imagining the Deep Structure of a Mineralized Extensional Dome in the Variscan Central Iberian Zone (Spain) using Ambient Noise Seismic Data. 

Imma Palomeras, Puy Ayarza, Juan Gomez-Barreiro, David Martí, José Ramón Martínez-Catalán, Yolanda Sánchez-Sánchez, Kelvin Dos Santos, Mariano Yenes, Irene Pérez-Cáceres, Santos Barrios, Javier Élez, and Irene DeFelipe

During the late stages of the Variscan orogeny, generalized gravitational collapse with coeval magmatism took place in the Central Iberian Zone, in Iberia. This event is getting the attention of the scientific community due to its likely role in the generation of strategic mineral resources (i.e. Sn, W, Nb, Ta, Sc, Au, Sb). In this regard, to study how the Variscan orogenic architecture controls the generation of mineral deposits the GOLDFINGER project was born. As part of the project, the Martinamor gneissic dome (Salamanca), which presents several mineral deposits, was covered by 31 short-period (2 Hz) 3-component seismic stations. Through applying techniques of ambient noise seismic interferometry, we have constructed a 3D S-wave velocity model of the extensional dome, allowing us to extend in depth the geometry of igneous rocks, their host rocks, and some of the structures. Among the most relevant results, we have identified the depth configuration of a granitic body outcropping discontinuously east of the study area, and whose upper boundary has been interpreted as the extensional dome detachment level. This structure may have provided a pathway for mineralizing fluids. This work demonstrates that the seismic noise interferometry technique has sufficient resolution to interpret medium-scale structures and to discern different lithologies with moderately contrasted physical properties.

Funding: grant PID2020-117332GB-C21 funded by MCIN/ AEI /10.13039/501100011033; EIT-Raw Materials project 17024 (SIT4ME: Seismic Imaging Techniques for Mineral Exploration); SA084P20 from the JCyL government, and TED2021-130440B-I00 funded by MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR.

How to cite: Palomeras, I., Ayarza, P., Gomez-Barreiro, J., Martí, D., Martínez-Catalán, J. R., Sánchez-Sánchez, Y., Dos Santos, K., Yenes, M., Pérez-Cáceres, I., Barrios, S., Élez, J., and DeFelipe, I.: Imagining the Deep Structure of a Mineralized Extensional Dome in the Variscan Central Iberian Zone (Spain) using Ambient Noise Seismic Data., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7869, https://doi.org/10.5194/egusphere-egu24-7869, 2024.

EGU24-10134 | ECS | Posters on site | ERE4.3

Sedimentological control on permeability heterogeneity, and its effects in fluid-flow modelling: a case study of the Middle Buntsandstein sandstones, Upper Rhine Graben, Eastern France 

Lucas Medeiros Bofill, Gerhard Schäfer, Guilherme Bozetti, Mathieu Schuster, Jean-François Ghienne, Philippe Ackerer, Claiton Scherer, Ezequiel Souza, and Garibaldi Armelenti

Sedimentary processes govern fluid-flow heterogeneities in porous media in several scales, therefore, their understanding is a common practice in the petroleum industry. However, hydrogeologists have lagged behind when it comes to discretising porous sedimentary aquifers in flow, heat and transport models. At the Upper Rhine Graben, in Eastern France, the Lower Triassic Buntsandstein Group serves as an important reservoir for groundwater and lithium-rich geothermal brines. The main objective of this study is to assess the architecture of the Lower Grès Vosgien Formation (LGV), Middle Buntsandstein, and how sedimentological processes, at different scales, generate significant permeability heterogeneities. It is implemented a high-resolution sedimentological characterisation, through vertical profile descriptions, digital outcrop model, and petrographic analysis. Subsequently, permeability measurements are coupled with sedimentological data, to identify different scales of sedimentary controls on permeability distribution. Finally, a realistic 2D hydrostratigraphic conceptual model is generated as a reference, allowing the evaluation of how different scenarios of heterogeneity simplification impact fluid-flow modelling, concerning particle residence time, macro-dispersivity, and upscaled anisotropy.

Results indicate that 93% of the LGV is composed of sandstones deposited by a braided fluvial system, with evidence suggesting that discharge variability was a main depositional controlling factor of sedimentary facies and heterogeneity distribution. The LGV stacking pattern reveals periods when fluvial processes were absent, and aeolian processes dominated sediment transport and deposition, comprising 7% of the total LGV thickness. The aeolian deposits record signs of persistent water in the system, either due to water table rise, or ephemeral floods, primarily contributing to the sedimentary facies association with the lowest permeabilities of the LGV, exceeding 3 orders of magnitude lower than the fluvial deposits. Despite representing only 7% of the LGV total thickness, the aeolian deposits exhibit lateral extensions that extrapolate outcrop scales (hundreds of metres), representing significant vertical flow baffle zones.

Fluid-flow simulations demonstrate that model simplifications, whether through assigning deterministic permeability values (mean), or stochastically distributing permeabilities, unconstrained by realistic sedimentary architectures, have a direct impact on macro-dispersivity (both vertical and horizontal), vertical mean residence time, and upscaled anisotropy results. Nevertheless, the results for horizontal mean residence time show no significant effect when simplifying the observed sandstone heterogeneities.

How to cite: Medeiros Bofill, L., Schäfer, G., Bozetti, G., Schuster, M., Ghienne, J.-F., Ackerer, P., Scherer, C., Souza, E., and Armelenti, G.: Sedimentological control on permeability heterogeneity, and its effects in fluid-flow modelling: a case study of the Middle Buntsandstein sandstones, Upper Rhine Graben, Eastern France, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10134, https://doi.org/10.5194/egusphere-egu24-10134, 2024.

EGU24-11471 | Posters on site | ERE4.3

Multivariate statistical analysis of mafic- and ultramafic-hosted seafloor massive sulfides 

Paolo Nimis, Nasser Aminizadkovij, Christine Meyzen, Luca Toffolo, Irina Melekestseva, Omar Paccagnella, and Clifford Patten

Seafloor massive sulfide (MS) deposits on oceanic spreading centers have variable concentrations of base metals (mostly Cu, Zn), precious metals (Au, Ag), critical metals (Co, Ni), and other trace elements. The geological factors that control this geochemical variability are still a matter of debate. In particular, the role of the composition of substrate rocks (specifically mafic vs. ultramafic) has been variably considered to be decisive or subordinate. In a previous study (Toffolo et al., 2020, Earth Sci. Rev.), we have investigated these factors by means of robust principal component and factor analysis of chemical data for MS samples from mid-ocean ridges worldwide. We found that a large part of the observed variability is produced by a combination of three independent factors, interpreted to reflect (in order of importance): (1) the temperature of deposition, which controls the relative enrichments in (Cu, Se, Co) vs. (Pb, Sb, Zn, Ag), (2) the ridge spreading rate, which influences the oceanic basement structure and the rock-to-water ratios, leading to opposite behaviors of (Au, Ag) vs. Ni, and (3) zone refining. Unexpectedly, the composition of the substrate did not emerge as a statistically significant independent factor. An important limit of our previous investigation was that literature data were often incomplete, thus limiting the number of samples and of chemical elements for the multivariate statistical analysis. We have now addressed this problem by using statistical imputation techniques and by integrating the database with additional literature and in-house data for present-day deposits on mid-ocean ridges and ancient deposits in ophiolites from different settings (supra-subduction-zone, mid-ocean ridge, ocean-continent transition). As a result, undersampling of ultramafic-hosted deposits was significantly reduced and the number of elements was raised to 11, including Cu, Zn, Pb, Au, Ag, Co, Ni, Se, Sb, Mo and the previously excluded As. The integrated database essentially confirms our previous findings. In addition, deposits in supra-subduction-zone ophiolites show factor scores typical of high deposition temperatures and high rock-to-water ratios, consistent with their formation on infant-arc, slow-spreading centers. The potential influence of other local geological factors will be discussed.

How to cite: Nimis, P., Aminizadkovij, N., Meyzen, C., Toffolo, L., Melekestseva, I., Paccagnella, O., and Patten, C.: Multivariate statistical analysis of mafic- and ultramafic-hosted seafloor massive sulfides, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11471, https://doi.org/10.5194/egusphere-egu24-11471, 2024.

Evaluating the geothermal potential of Africa requires a detailed understanding of its crustal and lithospheric structure. A coherent characterization of the geothermal gradient near the surface implies a bottom to top heat flow approach where knowledge of the thermal thickness of the lithosphere, the depth of the crust-mantle boundary, and crustal lithology (thermal conductivity and radiogenic heat production among other things) are essential. Unfortunately, direct measurements of subsurface temperature and local geophysical studies are scarce in most parts of Africa. In this work we present new predicted surface heat flow and crustal subsurface temperature maps, and new crustal structure models in Africa. The new models are obtained from a lithospheric integrated inversion approach using state-of-the-art surface waveform tomography data together with surface heat flow and elevation, crustal p-wave velocity and sedimentary thickness from controlled source seismic data. The inversion is framed within an integrated geophysical-petrological setting where mantle seismic velocities and densities are computed thermodynamically as a function of the in-situ temperature, pressure and compositional conditions. Within the three-layered crystalline crust, we invert for various geophysical parameters linked through lithology using global petrophysical measurements. The results of this work will be integrated into Project InnerSpace’s open-source GeoMap platform (https://projectinnerspace.org/), which aims to accelerate the uptake of geothermal energy by improving our knowledge of the subsurface.

How to cite: Clemente-Gómez, C., Fullea, J., Lebedev, S., Holdt, M., and Doran, H.: Mapping Africa’s geothermal potential: new surface heat flow and crustal temperature models from integrated geophysical-petrological inversion of surface wave and other data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12843, https://doi.org/10.5194/egusphere-egu24-12843, 2024.

EGU24-15177 | Orals | ERE4.3

Quality makes a difference: a preliminary update of the global continental heat flow dataset 

Sven Fuchs, Ben Norden, Florian Neumann, Elif Balkan-Pazvantoğlu, Samah Elbarbary, Alexej Petrunin, and Global Heat Flow Data Assessment Group

Recently, the International Heat Flow Commission (IHFC), the Task Force VIII of the International Lithosphere Program (ILP) and a global network of geoscientists have jointly developed new standards for the structure and the quality evaluation of heat flow-density data. Heat-flow data are important for understanding the temperature field at shallow depths to the lithospheric scale and thus are fundamental for geodynamic and tectonic processes as well as for geoenergy applications, like geothermal utilizations. It often builds an essential parameter for analytical or numerical models of subsurface thermal models. Since 2021, the Global Heat Flow Database is undergoing an intensive collaborative assessment considering the new defined standards. The new quality scheme, for the first time, will allow a joint classification of data in terms of (i) numerical uncertainty, (ii) methodological evaluation, and (iii) overriding or perturbing effects. On the example of the Global Heat Flow Database Release 2024, we present for a regional example how the assessment changes the data density and detail of information stored and how the new quality standards effect regional heat flow statistics.

How to cite: Fuchs, S., Norden, B., Neumann, F., Balkan-Pazvantoğlu, E., Elbarbary, S., Petrunin, A., and Heat Flow Data Assessment Group, G.: Quality makes a difference: a preliminary update of the global continental heat flow dataset, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15177, https://doi.org/10.5194/egusphere-egu24-15177, 2024.

EGU24-16175 | ECS | Posters on site | ERE4.3

Assessment of the Türkiye Heat Flow Database 2023 

Elif Balkan-Pazvantoglu, Florian Neumann, Ben Norden, and Sven Fuchs

Terrestrial heat-flow determinations are crucial for understanding the thermal structure of the lithosphere. This study presents the results of a revision of the heat flow database in Türkiye contributing to the Global Heat Flow Data Assessment Project conducted by the International Heat Flow Commission (IHFC). The database includes 750 heat flow determinations reported in Türkiye between 1991 and 2023, and are reassessed according to the new IHFC specific structure documented by Fuchs et al. (2023). The data are gathered from the original literature and examined to ensure complete documentation of relevant metadata. The quality score is assigned based on the uncertainty, methodology and environmental disturbances. The new national wide database shows that heat-flow determinations are predominantly distributed in the western part of the country. However, the eastern part of the country has been poorly investigated to date. Despite numerous exploration-based studies conducted in the region concerning its substantial geothermal potential, a noteworthy portion of thermal data remains archived and is not accessible. The study reveals a significant demand for additional heat flow determinations to allow the drawing of a substantially revised and robust heat-flow map. However, the ongoing update of the Türkiye Heat Flow Database already allows a more transparent identification of areas with thermal anomalies.

How to cite: Balkan-Pazvantoglu, E., Neumann, F., Norden, B., and Fuchs, S.: Assessment of the Türkiye Heat Flow Database 2023, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16175, https://doi.org/10.5194/egusphere-egu24-16175, 2024.

EGU24-16952 | Posters on site | ERE4.3 | Highlight

The heat flow data assessment project: Transformation of the global heat flow database 

Florian Neumann, Sven Fuchs, Ben Norden, Elif Balkan-Pazvantoğlu, Alexej Petrunin, Samah Elbarbary, Samuel Jennings, Kirsten Elger, Simone Frenzel, Nikolas Ott, Stephan Maes, and Global Heat Flow Data Assessment Group

Since its establishment in 1963, the International Heat Flow Commission (IHFC) has fostering and curating the Global Heat Flow Database (GHFDB). The dynamic nature of techniques and methodologies used in heat-flow density determination has necessitated regular updates to the database. Despite its widespread utility, the GHFDB faces challenges arising from variations in measurement techniques and data quality. Ongoing efforts are dedicated to overcoming these challenges, aiming to elevate the database's accuracy and reliability, thus solidifying its value within the scientific community. Multiple iterations of the GHFDB exist, primarily focused on characterizing the quality of individual heat-flow data points. However, the establishment of a new, authenticated GHFDB demanded the development of a fresh reporting standards for heat-flow data submitted to the IHFC. This new framework, derived from a collaborative global initiative, incorporates 62 metadata fields. This comprehensive approach became imperative due to the escalating volume of data and the diverse methodologies employed, necessitating a standardized scheme to evaluate the quality of heat-flow density determinations consistently. This update provides insights into the community-driven initiative initiated in 2021, targeting the reassessment of approximately 1,414 publications containing 73,033 global heat-flow data points. A noteworthy aspect of this initiative is the introduction of a novel quality scheme, unifying three independent criteria into a combined score. This score encompasses quantified uncertainty, methodological quality, and the status of overruling effects. The integration of these criteria facilitates a swift comparison of heat-flow data, instantly revealing any missing data or inadequately documented information. The introduction of this quality scheme empowers users to efficiently select reliable heat-flow values tailored to their specific research purposes.

How to cite: Neumann, F., Fuchs, S., Norden, B., Balkan-Pazvantoğlu, E., Petrunin, A., Elbarbary, S., Jennings, S., Elger, K., Frenzel, S., Ott, N., Maes, S., and Data Assessment Group, G. H. F.: The heat flow data assessment project: Transformation of the global heat flow database, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16952, https://doi.org/10.5194/egusphere-egu24-16952, 2024.

EGU24-22511 | Orals | ERE4.3

Exploring for the Future – precompetitive geoscience insight for resource discovery and development 

Karol Czarnota and Exploring for the Future Team

The world is turning to the mining sector to resource the Net Zero transition and meet sustainable development goals. It is generally agreed that global inventories of critical minerals, strategic materials, natural hydrogen, and carbon sequestration sites are insufficient to meet forecast demand thereby necessitating new discovery and development. At the same time exploration success rates are declining across the world as resources become harder to discover and develop. These factors are compounded by the long average lead time from discovery to resource extraction, making the imperative to act now to ensure a sustainable resource pipeline. To reverse this worrying trend Australia has invested heavily into precompetitive geoscience aimed at characterising the geological, geochemical, and geophysical architecture of Australia from the surface to the mantle and across scales from which new insights into the spatiotemporal controls on resource distribution are emerging. Uptake of this information by Australia’s entrepreneurial exploration sector has led to the highest exploration success rate in the world. Here, we will review the value of precompetitive geoscience in Australia within a global context and showcase results arising from the Exploring for the Future program, Australia’s flagship investment in precompetitive geoscience of $225 m over the last eight years.  Specifically, we will highlight new insights into processes controlling the spatiotemporal distribution of sediment and crystalline basement-hosted mineral systems arising from assessments of the predictive power of new national datasets (e.g., passive seismic, magnetotelluric, airborne electromagnetic and isotopic maps). We will conclude with how these insights can be integrated across scale within a systems framework to test the resource potential of frontier region for metals as well as hydrogen and carbon capture and storage.

How to cite: Czarnota, K. and Team, E. F. T. F.: Exploring for the Future – precompetitive geoscience insight for resource discovery and development, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22511, https://doi.org/10.5194/egusphere-egu24-22511, 2024.

EGU24-1413 | Orals | ERE4.4

Abandoned quarry reclamation by selecting the appropriate plant species. 

George Xiroudakis, George Saratsis, Kalliopi Gogali, and Maria Giannakaki

Mining activity has been an essential human activity since ancient times, contributing to human society's economic and cultural development. Today, surface mining activity in Greece is significant both economically and socially. A large number of quarries for aggregates and ornamental stones throughout the country contributes to the economic development of local communities and is the main occupations of mineral resources engineers.

However, it is an activity that significantly affects the natural environment, causing a range of impacts, reversible or irreversible, leading to the degradation of the area and visual alteration of the landscape. The environmental impact is considerable, and the concerns about protecting the landscape and ecosystems are growing. All thesecan be anticipated and dealt with by organizing and planning a landscape restoration study.

This research focuses on the landscaping and restoration of an aggregate quarry at the 'Latzimas' site in the prefecture of Rethymnon, Crete. In this context, two restoration proposals are made, including:

- the phytotechnical restoration of the quarry benches and pit floor using appropriate plant species,

- and the reuse of the quarry through the creation of a:

  • A) model vineyard,
  • B) botanical garden.

Usually, as the most suitable vegetation species are chosen the ones that thrive in the area instead of the ones that thrive in poor nutrient conditions, such as the environment of the abandoned quarries. Because of the above, the quarry engineer, who usually does not have the necessary knowledge of botany, will need to consult with experts (e.g. botanists and foresters) to ensure that the restoration plan is effective and not only aimed at meeting the obligations imposed by the legislation.

How to cite: Xiroudakis, G., Saratsis, G., Gogali, K., and Giannakaki, M.: Abandoned quarry reclamation by selecting the appropriate plant species., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1413, https://doi.org/10.5194/egusphere-egu24-1413, 2024.

EGU24-2791 | Orals | ERE4.4

Perspectives for the lignite post-mining landscapes of the lignite mining landscapes under changing environmental conditions – what can we learn from a comparison between the Rhenish and the Lusatian regions in Germany? 

Frank Lehmkuhl, Werner Gerwin, Thomas Raab, Klaus Birkhofer, Christoph Hinz, Peter Letmathe, Michael Leuchner, Martina Roß-Nickoll, Thomas R. Rüde, Katja Trachte, and Frank Wätzold

The German government's decision to phase out lignite mining by 2038 or earlier, as recently 2030 has been agreed for the Rhineland, will trigger a number of transition processes in Germany's remaining lignite mining areas. The two largest lignite mining areas are located in geographically different regions: Rhineland in the west and Lusatia in the east. As the socio-economic and environmental conditions in these two mining areas are set to change dramatically, the German government has adopted extensive economic support measures. However, the environmental changes will also lead to changes in the ecosystem functions and services provided by the future post-mining landscapes.

Gerwin et al. (2023) compare the two main lignite producing regions of Germany in terms of their natural and cultural environments. The economic situation and its history are reflected and differences are outlined. Part of the differences in cultural development can be explained by the natural conditions, especially the edaphic factors and the climatic situation. Because of the specific geological settings, tailored mining technologies were developed and used in the two regions, with different effects on the resulting post-mining landscapes.

We conclude that the landscapes of Lusatia and the Rhineland have been radically restructured by the long and varied history of lignite mining. Both regions will change significantly as the mining industry continues to decline and is expected to cease altogether within the next decade. These changes in the post-mining landscapes and the ecosystem services will provide both challenges and opportunities. The preconditions for positive socio-economic development and for sustainable land use concepts that also consider ecological aspects are different for the two regions. The exchange of knowledge and experience between the two mining regions is crucial to the success of this major transformation process, despite, or perhaps because of, these differences.

Gerwin, W., Raab, T., Birkhofer, K., Hinz, C., Letmathe, P., Leuchner, M., Roß-Nickoll, M., Rüde, T., Trachte, K., Wätzold, F., Lehmkuhl, F. (2023): Perspectives of lignite post-mining landscapes under changing environmental conditions: what can we learn from a comparison between the Rhenish and Lusatian region in Germany? Environmental Sciences Europe 35:36. https://doi.org/10.1186/s12302-023-00738-z

How to cite: Lehmkuhl, F., Gerwin, W., Raab, T., Birkhofer, K., Hinz, C., Letmathe, P., Leuchner, M., Roß-Nickoll, M., Rüde, T. R., Trachte, K., and Wätzold, F.: Perspectives for the lignite post-mining landscapes of the lignite mining landscapes under changing environmental conditions – what can we learn from a comparison between the Rhenish and the Lusatian regions in Germany?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2791, https://doi.org/10.5194/egusphere-egu24-2791, 2024.

EGU24-3385 | Posters virtual | ERE4.4

Leaching potential of coal waste organic compounds; a simulation study with fresh and saline water (Upper Silesia Coal Basin, Poland) 

Monika Fabiańska, Arkadiusz Goleniak, Magdalena Misz-Kennan, and Justyna Ciesielczuk

The vast amount of waste rocks excavated during coal mining and stored in dumps presents a significant environmental problem as they readily undergo spontaneous heating. The process produces large amounts of organic compounds, relatively well-soluble in water. The problem is severe because self-heating has been registered in many coal mining regions. The brine application as an anti-pyrogenic agent to prevent self-heating is a method that is still being developed. Its advantages are the ignition temperature increase, rock pores sealing by crystallizing salt, and permeability decrease, preventing contact with oxygen. Since there is no knowledge about the brine potential to leach organic compounds from coal wastes, this project aims to characterize components leached by rainwater and brine applied as an anti-pyrogen.

The Starzykowiec dump has stored coal wastes since the beginning of the 20th century. They consist of mudstones, siltstones, claystones, and arcosic sandstones. Most self-heating occurred from the 1940-60s. For the procedure, samples representing six rock types were selected, all thermally affected to different degree. Maceral composition and mineral content were determined at 500 points, and random reflectance was measured on vitrinite particles at 5-100 points. Two rock portions (ca 60g) powdered to <0.2 mm grain size were leached with 200 ml of distilled water and brine (25%, wt. NaCl), respectively (24h). Then, mixtures were stirred (30 min.) and set aside to settle. Leached organic compounds were isolated using solid phase extraction (SPE) on C18 PolarPlus columns. The composition of coal waste and SPE extracts were analyzed with a gas chromatograph-mass spectrometer (full scan mode, DB-5 column).

The content of organic matter was 35.0-88.2%. It was mostly unaltered or weakly weathered; only one sample was strongly altered. The unaltered and oxidized samples were composed mostly of vitrinite while strongly altered sample was dominated by masive coke. Since the Starzykowiec coal wastes were deposited for a few ten years in the dump, exposed to the air and rainwater, they have been weathered prior to the experiments. Despite that they still show leaching potential, particularly fine-grained coal muds; leaching yield 0.0003-0.0017% (wt.) for brine extracts and 0.0005 to 0.0029% (wt.) for water. There is a distinctive difference in composition between water and brine leachates. Water leachate n-alkanes show distributions similar to that in source coal waste, corresponding to mature kerogen type III. Biomarkers and PAHs are still present. The organic compounds in the brine show features of organic evaporates - a Gaussian n-alkanes outline in a short distribution, no heavier biomarkers, and only lighter PAHs occurring. These compounds were expelled from a kerogen macromolecule elsewhere within the dump and precipitated on colder fragments. They are not chemically bonded to organic matter and occur on the grains' surface; thus, the brine leached them, whereas the compounds present within the rock fragments were not removed.

Since leaching yields in the case of brine are significantly lower and less hazardous compounds such as n-alkanes are the main compounds removed, sodium chloride can also act as an anti-leaching agent as well as an anti-pyrogen.

How to cite: Fabiańska, M., Goleniak, A., Misz-Kennan, M., and Ciesielczuk, J.: Leaching potential of coal waste organic compounds; a simulation study with fresh and saline water (Upper Silesia Coal Basin, Poland), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3385, https://doi.org/10.5194/egusphere-egu24-3385, 2024.

EGU24-4123 | Posters on site | ERE4.4

Experimental evidence of extremally acidic environment due to self-heating of coal-mining wastes 

Justyna Ciesielczuk, Monika J. Fabiańska, Ádám Nádudvari, Magdalena Misz-Kennan, Krzysztof Gaidzik, and Anna Abramowicz

Coal exploitation has resulted in vast amounts of waste rocks gathered in dumps of different sizes, shapes and volumes. Changes due to their storage can lead to self-heating and self-ignition, which generate the acidification of coal wastes. Long-term burning leads to the sulphates and chlorides crust formation and sometimes hematite of spherulitic shape. A series of simple laboratory experiments were conducted to replicate the conditions leading to the formation of hematite spherules from goethite.

The first experiment involved heating at a low temperature. The starting materials were goethite α-FeOOH alone or goethite mixed with five reactants known from the coal-waste dumps (salammoniac NH4Cl, sulphur S8, phtalimide C8H5NO2, FeSO4·7H2O, naphthalene C10H8)  mixed in fifteen combinations and held at 150oC for 90 hours in a heating chamber. Hematite formed but particle shapes remained unchanged.

The second experiment was conducted at a higher temperature to verify if temperature alone is crucial to spherule formation. Temperatures measured at the burning dumps reach 1000oC. Goethite samples were held in a tubular furnace at 450-900oC in an open system for 90 minutes. Hematite formed but with irregular shapes, suggesting that other factors could be more critical.

Ubiquitous in dumps, water was added to the third experiment involving six combinations of reactants and a temperature of 150oC held for 78 h, pH = 5-7. Partially rounded hematite resulted from that bore little comparison with that seen in the dump.

The fourth experiment involved ten different mixtures of reactants (goethite, salammoniac, FeSO4·7H2O, naphthalene, NaCl, and powdered coal waste from the Radlin dump) heated in a tubular furnace at 700oC for 5 hours in an open system. The high temperature combined with unrestricted oxygen access resulted in the rapid crystallization of octahedral magnetite and platy hematite.

In the fifth experiment goethite in distilled water was mixed with NaCl and AlCl3, the temperature was relatively low (200oC), the duration was extended to 7 days, oxygen access was limited, and pH = 5-7. Cubic magnetite crystals and small hematite spherules with Ni or Cr impurities formed.

The sixth experiment conducted two mixtures: goethite + NaCl + AlCl3 + distilled water + MnSO4 and goethite + NaCl + AlCl3 + distilled water + FeSO4 in a semi-closed system at 200oC and lasted 16 days. The pH was lowered to 3. In addition to octahedral crystals of magnetite and shapeless hematite, spherules of Al- and (Al, Si) glass formed.

The seventh experiment was conducted in a semi-closed system with pH = 0, a low temperature of 200oC and a relatively long duration of 7 days. Under these conditions, and with goethite, AlCl3, MnSO4 and HCl as reactants, hematite spherules finally formed.

The laboratory experiments took into account the following factors noticed at burning coal waste dumps: temperature, fire duration, oxygen access, water presence, pH, reactants, their amount, combinations, state of matter, grinding, and mixing. Of these, pH stands out as crucial. It proves that hematitic spherules can be an indicator of an extremely acidic environment during the recent and earlier dump fires.

How to cite: Ciesielczuk, J., Fabiańska, M. J., Nádudvari, Á., Misz-Kennan, M., Gaidzik, K., and Abramowicz, A.: Experimental evidence of extremally acidic environment due to self-heating of coal-mining wastes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4123, https://doi.org/10.5194/egusphere-egu24-4123, 2024.

Preventing coal spontaneous combustion fire by using inhibitor is an effective control measure. The oxidized spontaneous combustion characteristics of coal can reflect the performance of coal, and a suitable structural model can reflect the performance of coal more intuitively, and can also lay the foundation for the study of the action mechanism of the inhibitor. In this study, samples from Baishihu coal mine were selected, and diethylenetriaminepenta-methylenephosphonic acid (DTPMP) was used as a blocking agent to investigate the macromolecular structure, microcrystalline structure changes and oxidation process of coal by X-ray photoelectron spectroscopy (XPS), carbon nuclear magnetic resonance (13C-NMR), and Fourier infrared spectroscopy (FTIR). The molecular formula C198H164O40N2 and the molecular structure model were obtained. ChemDraw and Materials Studio were used for the experimental data, and high-resolution transmission electron microscopy (HRTEM) was used to verify the aromatic ring structure built to make the constructed structural model more accurate. In the water evaporation stage, the high ring aromatic layer is converted into the low ring number. Furthermore, in the high-temperature stage, the low ring aromatic layer is transformed due to the coking and condensation reaction of the coal sample. With the increase in the treatment temperature, water loss is heavier, oxygen absorption and weight gain are perplexing, and the value of the burnout temperature is higher. The elemental composition of the coal samples was changed after the addition of the hindering agent, and the temperature at which small free radical molecules were produced and the time at which gaseous products appeared during the coal-oxygen reaction were delayed. The characteristic temperature increases with the increase of the resist concentration and the activation energy decreases in the water evaporation stage and increases in the other two stages. The apparent activation energy of the coal-oxygen reaction increases and the reaction becomes more hard and complex to realize. DTPMP mainly reacts with free radicals and reactive oxides and forms an adsorption layer on the coal surface. And the molecular structure of the inhibitor contains several phosphate functional groups, which can react with the oxides in the coal to form phosphate substances and fill the pores in the coal. It can reduce the evaporation of water and the contact of coal samples with oxygen. These mechanisms interact with each other and together reduce the reactivity of the coal and the risk of spontaneous combustion. This study furthers the understanding of coal spontaneous combustion in this mining area, provides a reference for the prevention and control of coal spontaneous combustion.

How to cite: Zhang, W. and Zeng, Q.: Study on the Effect of DTPMP Inhibitor on Oxidation and Structural Characteristics of Coal Spontaneous Combustion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4496, https://doi.org/10.5194/egusphere-egu24-4496, 2024.

EGU24-11549 | Orals | ERE4.4

Tools for managing metal contaminated areas: multidisciplinary approach to develop inputs for a more sustainable region 

Rui Jorge Oliveira, Bento Caldeira, Patrícia Palma, Maria João Costa, and Ana Fialho

This work aims to develop an environmental management model specifically designed for mining areas that have been contaminated by toxic metals. A sustainable management model is suggested to be established, utilizing a combination of developed tools. This model will provide tools and strategies to effectively manage and mitigate the environmental impact of such contamination, with the goal of promoting an increment of sustainability in these regions. The environmental management model combines the outcomes of employing a range of analytical techniques and tools to monitor polluted regions, including biophysical analyses, analysis of soil and water chemistry (measuring quality physic-chemical parameters and quantifying potentially harmful metals in soil and water samples), geophysics (using magnetic, electromagnetic, electrical, and seismic methods), and satellite hyperspectral remote sensing. The artificial intelligence model will utilize the data gathered from many domains as its inputs. On the other hand, a plan for the economic and financial viability of the management model will be formulated.

With the model we aim to optimize and conserve resources during the sampling and analysis phases. It will provide crucial real-time information for decision-making, specifically for monitoring and managing pollution. The device has wide-ranging utility in identifying metal pollution, facilitating the transfer of technology to various geographical regions and other metal contamination situations, such as landfills and agricultural fields.

Through our multidisciplinary approach, we anticipate diverse contributions to the region affected by metals contamination. The region benefits from the adoption of new strategies that improve current routines, streamline procedures, and ensure timely execution. This leads to positive environmental, social, and economic outcomes, including resource conservation, remediation of contaminated sites, restoration of ecosystem balance, improved company performance, reduced environmental impact, and promotion of regional sustainability.

Acknowledgment: The work was supported by the Promove Program of the “la Caixa” Foundation, in partnership with BPI and the Foundation for Science and Technology (FCT), in the scope of the project INCOME – Inputs para uma região mais sustentável: Instrumentos para a gestão de zonas contaminadas por metais (Inputs for a more sustainable region: Instruments for managing metal-contaminated areas), PD23-00013. The work was carried on in the scope of the funding by the Portuguese Foundation for Science and Technology (FCT) project UIDB/04683/2020 - ICT (Institute of Earth Sciences).

How to cite: Oliveira, R. J., Caldeira, B., Palma, P., Costa, M. J., and Fialho, A.: Tools for managing metal contaminated areas: multidisciplinary approach to develop inputs for a more sustainable region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11549, https://doi.org/10.5194/egusphere-egu24-11549, 2024.

EGU24-11829 | Orals | ERE4.4

Lead isotopic composition of the oxidized Cu ores, slags and soils from the Old Copper Basin, Poland and its implications for metal-provenance and environmental research 

Anna Pietranik, Katarzyna Derkowska, Jakub Kierczak, Vojtech Ettler, and Martin Mihaljevič

In this study, we report lead isotopic compositions from oxidized Cu ores, host rocks, metal smelting residues, and soils from the Zechstein Ca1 formation which is associated with the Kupferschiefer copper deposits. The lithology is dominated by marls and slates, where Cu mineralization appears in carbonates, mostly malachite. Historical smelting left numerous slag remnants around the site (Derkowska et al. 2023). The Pb isotope ratios in ores and slags are highly diverse in comparison to previous studies of Cu ores and smelting products in Poland (Tyszka et al. 2012), i.e. 206Pb/207Pb ratio ranges from 1.094 to 2.092 for ores and from 1.151 to 1.240 for slags. This diversity is likely related to the oxidized character of the ore, which contains less Pb compared to sulfide-dominated ores and, in consequence, its Pb isotopic composition is dominated by radiogenic Pb produced by U-rich host rocks. This translates to significant differences in Pb isotope records between oxidized and reduced (sulfide) deposits that can be utilized in environmental and provenance studies. Similar diversity in soil samples is consistent with contamination by such ores and/or slags. Analyzed soils show highly variable 206Pb/207Pb ratios in lower soil horizons, whereas Pb isotope ratios in topsoils are similar to those typical for a whole region of Lower Silesia in Poland (1.17-1.19). This suggests the dominance of modern atmospheric Pb in the surface environment which we link to Polish and Czech coal combustion and name as the Lower Silesian Contemporary Pollution Signal.

Our study shows that using oxidized Cu-ores may introduce high diversity in Pb isotopic composition to smelting products, wastes, and consequently the environment. This affects both environmental and provenance studies as only a restricted isotope ratio can be attributed to a single source. On the other hand, high diversity in 206Pb/207Pb ratios in slag samples may also indicate the addition of oxidized Cu ores during smelting thus may be also an asset to identify when oxidized ores were used or acted as a pollution source.

Acknowledgments: The study is funded by the National Science Centre grant to KD (2019/35/N/ST10/04524)

Derkowska K., Kierczak J., Potysz A., Pietranik A., Pędziwiatr A., Ettler V., Mihaljevič M., 2023, Combined approach for assessing metal(loid)s mobility and accumulation in a near-neutral (pH) environment of a former Cu-smelting area in the Old Copper Basin, Poland: when nature is the ‘bad guy’. Applied Geochemistry, 105670. https://doi.org/10.1016/j.apgeochem.2023.105670

Tyszka R., Pietranik A., Kierczak J., Ettler V., Mihaljevič M., Weber J., 2012, Anthropogenic and lithogenic sources of lead in Lower Silesia (Southwest Poland): an isotopic study of soils, basement rocks and anthropogenic materials. Applied Geochemistry, 27, 1089-1100, http://dx.doi.org/10.1016/j.apgeochem.2012.02.034

How to cite: Pietranik, A., Derkowska, K., Kierczak, J., Ettler, V., and Mihaljevič, M.: Lead isotopic composition of the oxidized Cu ores, slags and soils from the Old Copper Basin, Poland and its implications for metal-provenance and environmental research, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11829, https://doi.org/10.5194/egusphere-egu24-11829, 2024.

EGU24-12399 | Orals | ERE4.4

Satellite and UAV monitoring of legacy mine sites via secondary iron mineral proxies. Case studies from the Republic of Cyprus and Australia 

Justus Constantin Hildebrand, Friederike M. Koerting, Ekaterina Savinova, Steven Micklethwaite, Peter D. Erskine, David Lindblom, Matthew Greenwood, Dominic Brown, and Nicole Koellner

Challenge 

While recycling and alternative technologies show promise in reducing reliance on primary raw materials, the direct acquisition of essential metals and minerals depends on extracting new resources. The increasing demand for these resources has significant implications for mining, mineral processing, and environmental impact. Failing to effectively manage this demand for raw materials and mitigate the environmental impact of mining could impede global progress towards a cleaner energy future. The M4Mining project aims to promote sustainable mining practices using integrated remote sensing data to help monitor these operations. Its primary objective is to develop comprehensive remote sensing solutions for mining and tailings sites. This abstract introduces the identification of secondary iron minerals as proxies for estimating possible acid mine drainage (AMD) occurrence in legacy mine sites in both Cyprus and Australia.

Methodology 

Hyperspectral data of the secondary iron minerals hematite, goethite, limonite (goethite + lepidocrocite), jarosite and copiapite were collected in a laboratory setting to develop a method to separate secondary iron minerals from other minerals. Filtering by threshold of various indices, NDVI, ferric iron index, and iron feature band ratio, were best suited for this purpose. After filtering, the remaining pixels of the secondary iron minerals were predicted using a random forest (RF) classifier-model. It was possible to distinguish between the mineral classes hematite, goethite/ lepidocrocite and jarosite with over 93% area adjusted overall accuracy using 30 random control pixels for both sensors.

Results 

The first case study is applied is the Cu-Au-Pyrite mine Skouriotissa in the Republic of Cyprus. A spectral resampling from the hyperspectral laboratory data to Sentinel-2 (S2) and WorldView-3 (WV3) spectral resolution made it possible to adjust the hyperspectral method and provide results for both satellite sensors. Comparing the resulting maps show differences of minerals mapped on the surface likely due to the sensor’s different spatial resolution (S2 20m vs WV3 3.7m pixel). 

The M4Mining partners completed their first field survey in North-Western Queensland at the Mary Kathleen legacy mine site in September 2023. The former Uranium (U) open pit mine was active until 1982 and rehabilitated in 1985. The area was surveyed via UAV-borne hyperspectral data collection and satellite-borne hyperspectral (EnMap) instruments to assess the site's rehabilitation status. The method tested in the Republic of Cyprus is being applied to the Mary Kathleen site to evaluate surface oxidation processes that could indicate acid pH environments. A special focus is set on the gradient between the capped evaporation pond and the surrounding environment including the discharge area from the former pond. Different standard hyperspectral and multispectral algorithms are used to map the spatial distribution of iron oxides and evaporates. Although a final evaluation of the rehabilitation of the area is outside the scope of this study, the data collected intend to add valuable information to the continued monitoring of the site. 

Preliminary results from Australia will be provided for relative surface changes as indicators for processes occuring under the capped evaporation pond.

How to cite: Hildebrand, J. C., Koerting, F. M., Savinova, E., Micklethwaite, S., Erskine, P. D., Lindblom, D., Greenwood, M., Brown, D., and Koellner, N.: Satellite and UAV monitoring of legacy mine sites via secondary iron mineral proxies. Case studies from the Republic of Cyprus and Australia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12399, https://doi.org/10.5194/egusphere-egu24-12399, 2024.

EGU24-14890 | Orals | ERE4.4

Fire progression within coal waste heap in Heřmanice, Upper Silesia, Czech Republic 

Dariusz Więcław, Krzysztof J. Jurek, Eva Geršlová, Tomasz Kowalski, and Elżbieta Bilkiewicz

In the Czech part of the Upper Silesian Coal Basin (USCB), there are several places of coal wastes storage. Within improperly protected heaps, the self-heating and spontaneous burning processes may develop, resulting in the emission of gaseous, water-soluble and solid (tars, dust) pollutants.

The thermal processes have developed within the heap in Hermanice (Ostrava) since the 1990s. Recently, the most thermally active is the eastern part of the deposit. The purpose of the study was to evaluate the progression of the fire based on temperature measurements, molecular and stable isotope composition of gases emitted from thermally active parts of the deposit. The sampling was conducted in the same places in January, April and September 2023. One of the sampled points was a steel pipe that penetrated the dump to a depth of ca. 12 m, where, according to Diamo Ltd., it was ca. 350 °C. The other 3 sampling points were located in areas of visible thermal activity (steam or smoke emissions). Surface temperature measurements in these spots ranged from 3 to 345 °C, and at the probe depths (50-100 cm), from 66 to 363 °C. Gases were taken at each point twice: directly from the chimney where the outflow of gas/vapour was visible (sample SURF) and after sticking the probe into the ground (sample DEEP).

During the study period, in the zone of intense thermal processes (southeastern part of the heap), large changes in temperature and gas concentrations (N2, O2, hydrocarbons (HC), CO, CO2, H2 and S-compounds) were noted. In general, SURF gases were found to be richer in pollutants than DEEP gases. This suggests that the gases coming to the surface flow from much deeper parts of the heap than those reached with the sampling probe. The highest concentrations of CO2 (19.17%), CO (0.67%), HC (2.43%), H2 (6.26%) and S-compounds (844 ppm) were found in April in gas coming out of the pipe (from the highest temperature, ca. 350oC). In September, the zone with the highest temperatures shifted to the north, and the concentrations of monitored gases generally decreased, indicating material burnout in the hot spot. The δ13C(CH4), δ2H(CH4), and δ13C(CO2) values indicate the thermogenic origin of all gases.

At a point ca. 100m away from the hot spot, temperatures of ca. 65-75oC were found during all measurements, and the gas composition was independent of the sampling depth. The highest concentrations of CO2 (20.21%), HC (3.30%) and H2 (0.5%) were found during the April campaign. The isotopic composition of selected gases suggests their relation to low-temperature thermogenic processes; the presence of a component of microbial origin is not excluded.

The data presented here show that the molecular and isotopic composition analysis of gases is a good tool for tracking processes in thermally active coal waste dumps.

This study was financed by the AGH University of Krakow as a part of the programme Excellence Initiative – Research University, Action 4, Grant No. 4113.

How to cite: Więcław, D., Jurek, K. J., Geršlová, E., Kowalski, T., and Bilkiewicz, E.: Fire progression within coal waste heap in Heřmanice, Upper Silesia, Czech Republic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14890, https://doi.org/10.5194/egusphere-egu24-14890, 2024.

EGU24-15014 | Posters virtual | ERE4.4

Polycyclic aromatic hydrocarbons (PAHs) and their derivatives in soils developing on coal waste dumps from the Upper Silesia, Poland 

Wioleta Śmiszek-Lindert, Monika Fabiańska, Leszek Marynowski, and Marzena Barczyk

In southern Poland, the mining industry led to the creation of diverse post-mining waste deposited in dumps. Therefore, it is essential to study and monitor the condition of soils developing there. The soil samples have been collected from the coal waste dump at the Ziemowit Coal Mine in Upper Silesia, Poland. The aim of the research was to determine the extent of soil contamination by polycyclic aromatic hydrocarbons (PAHs) and their derivatives within the soil profile on the dump that was not subjected to thermal phenomena (self-heating).

Soil samples were taken at depths of 0, 20, and 40 cm. Powdered samples (ca. 10 g) were extracted using a dichloromethane (DCM)/methanol mixture (1:1 v:v) with an accelerated Dionex ASE 350 solvent extractor. The samples were analysed using GC–MS carried out with an Agilent Technologies 7890A gas chromatograph and Agilent 5975C Network mass spectrometer.

The PAHs detected included phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b+k]fluoranthene, benzo[j]fluoranthene, benzo[a]fluoranthene, benzo[a]pyrene, benzo[e]pyrene, perylene, indeno[1,2,3-cd]pyrene, benzo[ghi]perylene, dibenzoanthracenes, and coronene together with their alkyl derivatives in the range of C1-C4. Concentrations of highly carcinogenic PAHs such as benzo[a]pyrene (ca. 0.95 µg/g), benzofluoranthenes (ca. 0.17-3.34 µg/g), and benzo[a]anthracene (ca. 1.70 µg/g) have been determined in all samples. Due to the combined effects of weathering and leaching by waters penetrating the highly permeable dump lighter PAHs were partially or totally removed, among them naphthalene and alkyl naphthalenes up to C3, fluorene, acenaphthene, and acenaphthylene. There are significant differences in compounds absence with sampling depth, i.e. the least leached soils were sampled deepest and closest to the coal waste level, where even C2 naphthalenes were preserved. In PAHs distribution predominate 4- to 5-rings compounds, however also heavier 6-rings PAHs were found.

The results show that coal waste dump soil, even there where self-heating is absent, can contain significant amounts of PAHs making it a potential source of contamination spreading, particularly during dry seasons when soil dusting occurs or due to leaching by rain water to nearby water reservoirs.

How to cite: Śmiszek-Lindert, W., Fabiańska, M., Marynowski, L., and Barczyk, M.: Polycyclic aromatic hydrocarbons (PAHs) and their derivatives in soils developing on coal waste dumps from the Upper Silesia, Poland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15014, https://doi.org/10.5194/egusphere-egu24-15014, 2024.

EGU24-16327 | ECS | Posters on site | ERE4.4

Modeling variably saturated water flow within planned covers of a hypothetical potash tailings pile 

Felipe Edgardo Silva Monsalves and Thomas Graf

Potash mining to obtain potassium generates large quantities of solid waste composed mainly of sodium chloride, accompanied in lesser quantities by magnesium sulfate and magnesium chloride, as well as insoluble clay minerals. The solid waste is disposed off on the ground surface to form tailings piles. In central Germany, there are dozens of potash tailings piles, some of which are more than two hundred meters high and form a unique landscape due to their appearance and lack of vegetation. Potash tailings are therefore exposed to climatic conditions such as rainfall, which may potentially dissolve salt, thus affecting the surrounding ecosystem including surface water bodies and groundwater. The environmental impact can likely be mitigated by applying soil covers over the potash tailings to limit and, in the best case, prevent the contact of the percolating water with the saline core of a pile. The efficiency of the soil covers is increased by applying a perennial vegetation layer to reduce the amount of water infiltration by interception, evaporation and plant transpiration. Therefore, the design of a cover system is based on the hydrological processes of the site, which include precipitation, surface runoff, evapotranspiration, in- and exfiltration and the water storage capacity of the soil. In addition, the type of soil cover and thus its hydraulic characteristics, the number of layers, the thickness of each layer, as well as the angle of slope of the layers can significantly influence the long-term efficiency of the cover. In conclusion, understanding the synergy between the soil cover and the potash tailing is essential to determine the effects caused on the surrounding environment, in particular on groundwater. The objective of this research work focuses on the numerical simulation of variably saturated water fluxes, in particular the creation of a water balance between surface runoff, in- and exfiltration and evaporation loss to the atmosphere in the soil cover. For this purpose, different configurations of vegetation covers are investigated and the capillary barrier effects are analyzed for each of them. The water flow through the potash tailing produced by the remaining infiltration through the vegetation cover is modeled for a hypothetical geometrical setting of a representative tailings pile.

How to cite: Silva Monsalves, F. E. and Graf, T.: Modeling variably saturated water flow within planned covers of a hypothetical potash tailings pile, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16327, https://doi.org/10.5194/egusphere-egu24-16327, 2024.

EGU24-16597 | ECS | Posters on site | ERE4.4

The carbon stable isotope composition of PAHs released during thermal processes in self-heating coal waste Heřmanice dump, Czech Republic  

Krzysztof J. Jurek, Mariola Jabłońska, Eva Geršlová, Ewa Szram, Monika Fabiańska, Tomasz Kowalski, and Dariusz Więcław

Coal wastes are a by-product of coal mining. Regardless of the extraction technique (opencast or deep mining), coal wastes are disposed of in dumps. The heaps are an integral element of the industrial landscape of the Czech part of the Upper Silesian Coal Basin, where bituminous coal has been mined since the 18th century. The Heřmanice dump is the largest, partially burning dump in the Czech part of the Upper Silesian Coal Basin. The dump was used to store waste from several mines in northern Ostrava (Ida Mine, Viktoria - Generalissimus Stalin II - Rudý Říjen – Heřmanice Mine) up to 1970. The self-heating process began in the dump's southeast in the early 1990s and has extended northward to the eastern part of the heap. Polycyclic aromatic hydrocarbons (PAHs), naturally occurring in coaly material during waste self-burning are emitted into the atmosphere with particulate matter (PM).

The concentrations and stable carbon isotope compositions of PAHs associated with PM collected on glass fibre filters using a Senya high-flow aspirator were analysed using gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) and compound-specific isotope analysis (CSIA). The PM samples were collected from the same three exhalations on the dump in the winter, spring, and autumn. Following sample collection, the internal temperature of the dump was measured at a depth up to 100 cm below the surface. In dichloromethane extracts of glass fibre filters obtained by ultrasonic extraction, phenanthrene and fluorene predominate regardless of subsurface temperature or season. PAHs emissions differ depending on the stage of combustion. The highest levels of PAHs emission are related to subsurface temperatures ranging from 200 to 250 °C (the main stage of the self-heating process). At low (initial stage) and high (final stage) temperatures PAHs are released in low concentrations. However, the composition of stable carbon isotopes of phenanthrene and fluorene might be helpful to distinguish the stage of the process. Phenanthrene and fluorene related to low temperatures are isotopically heavier than those exhaled at high temperatures. As a result, CSIA might help evaluate the progress of the self-heating process at coal waste heaps.

This study was financed by the AGH University of Krakow as a part of the programme Excellence Initiative – Research University, Action 4, Grant No. 4113.

How to cite: Jurek, K. J., Jabłońska, M., Geršlová, E., Szram, E., Fabiańska, M., Kowalski, T., and Więcław, D.: The carbon stable isotope composition of PAHs released during thermal processes in self-heating coal waste Heřmanice dump, Czech Republic , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16597, https://doi.org/10.5194/egusphere-egu24-16597, 2024.

EGU24-17671 | Posters virtual | ERE4.4

Oxidative simulation of self-heating mechanisms in coal wastes with low-rank organic matter 

Marek Szczerba, Magdalena Misz-Kennan, Dariusz Więcław, Monika Fabiańska, and Justyna Ciesielczuk

Self-heating in coal waste dumps is a process depending on variable factors; thus, laboratory simulations are required to find their extent and importance in coal waste alterations. Controlled and known conditions allow us to assess the impact of oxidation on coal waste properties.

Low-rank coal wastes from the Janina Mine (sub-bituminous coal, Upper Silesian coal basin, Poland) were the object of oxidation simulation, performed using the Hastelloy C-276 1-liter reactors (Parr Instrument Co.). For this purpose, ca. 40 and 150g (JAN-1) and ca. 15 and 27g (JAN-2) of the gravel-size (0.5-2.0 cm) coal wastes were heated to 250 and 400°C for 72h in the air atmosphere (synthetic, Air Liquide S.A.). Each experiment was conducted twice using different sample weights. The air-to-rock proportions were established based on stoichiometric calculations taking into account the amount of oxygen in the reactor equivalent to half of the requirement to burnout of organic carbon (from ca. 7 to 38 bar). Gaseous and solid products were collected after the experiments were completed. When the JAN-2 sample was heated to 250°C, the organic matter ignited (at 250°C), resulting in dust emissions and plugging of the manometer connector, which made it impossible to take a gas sample.

Samples of coal wastes oxidized in the experiment were embedded in epoxy resin and prepared for microscope observations in reflected white light and fluorescence using a Carl Zeiss AxioImager.A2m microscope equipped with a 50× oil objective.

Organic matter in coal wastes was dominated by vitrinite, with inertinite and liptinite occurring in lower amounts. The impact of oxidation was mostly seen in vitrinite particles that had paler in colour oxidation rims. Smaller particles and thin lamina of vitrinite were entirely paler in colour and had higher reflectance. That was more seen in mudstone samples containing lower amounts of organic matter compared to claystone. On the other hand oxidation rims were common in claystone as vitrinite particles were thicker.

Iron released from pyrite leads to the formation of oxides and the red color of some of the samples. Contents of illite-smectite and amorphous phases increased during the experiments, while kaolinite was a mineral that was the most affected by the ignition, and its content decreased significantly. 

Larger heterogenous particles of mudstone containing thicker bands of organic matter showed different impacts of temperature. Some liptinite particles were devolatilised but their colour and fluorescence were little changed; others were paler in colour. Vitrinite was plasticised and often had a paler colour. In other parts of the sample organic matter was absent or present as small cracked vitrinite particles and very thin lamina of collotelinite.

The lower grain size of coal wastes causes more extensive alteration due to a higher surface/volume ratio that leads to better exposure to high temperatures. Mudstone samples were more affected, showing paler particles, whereas claystone samples did not show such an effect. The phenomenon at 250°C is much less pronounced. The research shows the significance of laboratory simulation in the investigation of such chaotic and multi-factored processes as self-heating.

How to cite: Szczerba, M., Misz-Kennan, M., Więcław, D., Fabiańska, M., and Ciesielczuk, J.: Oxidative simulation of self-heating mechanisms in coal wastes with low-rank organic matter, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17671, https://doi.org/10.5194/egusphere-egu24-17671, 2024.

EGU24-18871 | ECS | Orals | ERE4.4

Reactive transport modelling as a toolbox to compare remediation strategies of aquifers impacted by uranium in situ recovery 

Nicolas Seigneur, Niya Grozeva, Bayarmaa Purevsan, and Michaël Descostes

Worldwide uranium production is based on the In Situ Recovery mining technique. This exploitation mode directly falls within the scope of the applications of reactive transport modelling to optimize uranium production and limit its associated environmental impact. We hereby propose a modelling approach which is able to represent the natural evolution of the aquifer impacted by the exploitation of an ISR test. Model is calibrated on 12 year-long data obtained from 12 monitoring wells surrounding the ISR pilot cell. Through this process based approach, we simulate the impact of several remediation strategies which could be considered in these contexts. In particular, we model the impact of pump and treat combined with reverse osmosis as well as the circulation of non-impacted fluids through the reservoir with different operating strategies. We show that our approach allows to compare the effectiveness of these strategies. We show that, for this small-scale ISR pilot, monitored natural attenuation constitutes an interesting approach due to its faster pH recovery time with respect to Pump & Treat and circulation of unimpacted fluids. Combined with an economical evaluation of their deployment, this approach can help the mining operator select and design the optimal remediation strategies, from an environmental and economical standpoint.

How to cite: Seigneur, N., Grozeva, N., Purevsan, B., and Descostes, M.: Reactive transport modelling as a toolbox to compare remediation strategies of aquifers impacted by uranium in situ recovery, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18871, https://doi.org/10.5194/egusphere-egu24-18871, 2024.

EGU24-19363 | ECS | Orals | ERE4.4

Multi-criteria optimization of uranium exploitation by In Situ Recovery  

Razane Doucmak, Nicolas Seigneur, Sofia Escario, Vincent Lagneau, and Michael Descostes

Worldwide, In situ recovery (ISR) is the most widely used uranium mining technique. As of 2022, it accounted for 55% of global uranium production. Uranium ISR consists in dissolving the ore minerals using an acidic leaching solution directly within the deposit through a series of injection and extraction wells. The U-enriched solution is then pumped to the surface in order to separate the dissolved uranium from the acid solution. Reagents are then recycled before being reinjected into the deposit. The key advantage of ISR over conventional underground and open-pit mining lies in its significantly

reduced costs and environmental footprint since it generates no tailings or solid waste and does not require excavation of the rock. It is by far the most cost effective extraction technique. However, an ISR exploitation impacts the groundwater quality by increasing the concentration of dissolved elements (SO4, ...) and decreasing the pH. Subsequently, groundwater impacted by acid ISR mining is typically remediated using various rehabilitation strategies.

 

This study aims to forecast uranium production and predict the long-term environmental footprint of such exploitation using a reactive transport modeling approach. To do so, we will use HYTEC,  an  investigative tool to assess both production and the environmental footprint of an ISR mining site. HYTEC includes the three-dimensional hydrogeochemical simulation of the relevant chemical reactions which govern uranium production and the long-term evolution of the aquifer. The model is applied to an uranium deposit of the KATCO mine in Kazakhstan that has not been exploited yet. This model can simulate the 3D evolution of the aquifer geochemistry during and after the production phase.

 

We will study how operating parameters (well design, injection-production rates, acidity and oxidation levels, …) impact both the uranium production and the environmental footprint of the ISR exploitation. The environmental footprint can be described in terms of distance and time. The distance is generally controlled by the migration of sulfate ions resulting from the injection of sulfuric acid, which have low reactivity and hence an important mobility. Acidity or pH is the parameter which influences the duration of the impact, as H+ has a very important reactivity and can also be stored locally by adsorption on clay mineral surfaces. The geochemical model, previously developed in a separate study, suggests that cationic sorption on clay surfaces and the precipitation of secondary minerals like gypsum regulate the behavior of contaminants (SO4, pH) over extended durations and distances.

How to cite: Doucmak, R., Seigneur, N., Escario, S., Lagneau, V., and Descostes, M.: Multi-criteria optimization of uranium exploitation by In Situ Recovery , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19363, https://doi.org/10.5194/egusphere-egu24-19363, 2024.

EGU24-20556 | ECS | Orals | ERE4.4

Towards Sustainable Mining: Geopolymer Formulations for Eco-Friendly Mine Waste Management and Recycling 

Jihene Nouairi, Slavka Andrejkovičová, Omaima Karoui, Tiago Pinho, Rafael Rebelo, Fernando Rocha, and Mounir Ghribi

The demand for environmentally friendly materials in our habitat is a major challenge. Alkali activation, such as in geopolymers, offers a potential solution for waste valorization, providing an alternative to cement-based materials and contributing to the circular economy.

This study explores the use of mine waste from an abandoned Pb-Zn site in Northern Tunisia as an inexpensive and high adsorption capacity additive in the synthesis of geopolymers. The mine waste was used to replace metakaolin in the geopolymer formulations to minimize the environmental impact. Two types of metakaolin (commercial 1200S MK, AGS Mineraux, France and Portuguese Vicente Pereira, VPMK) were used in the formulations. Microstucture, mechanical properties, and Methylene Blue dye adsorption were studied.

Results revealed alarming concentration of potentially toxic elements in the mine waste (28.040 mg kg−1 Pb and 94.420 mg kg−1 Zn), presenting an environmental hazard and pointing up the need to stabilize these materials in order to prevent leaching.  Mechanical behaviour at 28 days of curing was promising (up to 32MPa) in the case of the VP based metakaolin formulations. The microstructure, studied by SEM, is consisted of voids, macro and meso pores, giving the geopolymers a high adsorption capacity. The synthetized geopolymers were utilized for the adsorption of methylene blue (MB) by investigating the effect of the amount of the adsorbent and the shaking period. The batch kinetics study fitted best into the pseudo second order reaction kinetic model. In isotherm modelling studies, the Langmuir isotherm model was best fitted and was used to describe the mechanism of the adsorption. Samples with 40 wt.% VPMK and 100 wt.% MK showed the best adsorption capacity revealing the effect of the waste in the amelioration of the alkali-activated metakaolin based geopolymers and its potential in the restitution of metakolin.

How to cite: Nouairi, J., Andrejkovičová, S., Karoui, O., Pinho, T., Rebelo, R., Rocha, F., and Ghribi, M.: Towards Sustainable Mining: Geopolymer Formulations for Eco-Friendly Mine Waste Management and Recycling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20556, https://doi.org/10.5194/egusphere-egu24-20556, 2024.

EGU24-2202 | Orals | ERE4.5 | Highlight

Repurposing former underground coal mines by deploying emerging renewable energy and circular economy technologies 

Pedro Riesgo Fernández, Alicja Krzemień, Gregorio Fidalgo Valverde, Antonio Luis Marqués Sierra, and Francisco Javier Iglesias Rodríguez

This presentation introduces the Research Fund for Coal and Steel (RFCS) GreenJOBS project, which approach is premised on leveraging five competitive advantages of underground coal mines to deploy emerging renewable energy and circular economy technologies:

(1) mine water for geothermal and green hydrogen. Geothermal energy is a renewable source that harnesses the heat from inside the earth, in our case, through the water that floods the mines. From a certain depth, the temperature of the subsoil is constant regardless of the season. Thus, a continuous and accessible energy source is available all year round. On the other hand, mine water represents an essential raw material for producing green hydrogen by electrolysis;

(2) connections to the grid that can be adapted to inject the electricity produced;

(3) large waste heap areas for installing photovoltaic/wind;

(4) deep shafts suitable for unconventional pumped hydro storage using dense fluids that has a smaller footprint and higher energy density than conventional pumped hydro energy systems; and

(5) fine coal waste for recycling into dense fluids employed by the unconventional pumped hydro storage; artificial substitutes for soils from coal waste and wastes from closely located agricultural industries, coal-fired power plants, and water plants; and rare earths from fine coal wastes.

The objective is to provide mining companies with two innovative business plans: a Virtual Power Plant where the energy produced will be sold to the grid or used to power electro-intensive industries or companies with constant energy consumption located close to mines, such as aluminium factories or green data centres; and a Green Hydrogen Plant where renewable hydrogen will be produced by electrolysis of mine water and electricity from renewable sources.

How to cite: Riesgo Fernández, P., Krzemień, A., Fidalgo Valverde, G., Marqués Sierra, A. L., and Iglesias Rodríguez, F. J.: Repurposing former underground coal mines by deploying emerging renewable energy and circular economy technologies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2202, https://doi.org/10.5194/egusphere-egu24-2202, 2024.

EGU24-3065 | Orals | ERE4.5 | Highlight

A GIS-Based Decision Support System for Multi-Hazard Assessment in Post-Mining Regions 

Moncef Bouaziz, Bejamin Haske, Marwan Al Heib, and Joerg Benndorf

Abandoned mines are generally exposed to multi-hazard: natural and man-mad hazards. The risk assessment is one of the challenges of the site management. This paper presents first the categories of hazards and potential interactions, then it shows a Geographical Information System (GIS)-based Decision Support System (DSS), as part of the European research project titled "POst-mining Multi-Hazards Multi-Assessment for Land-Planning (POMHAZ)." Utilizing predominantly open-source tools (PostGIS, Geoserver, and Leaflet) and Python Scripts, the DSS aims to tackle the intricate challenges posed by post-mining hazards in European mining regions. The objective is to furnish a functional web-based tool tailored for EU administrative units, ensuring a comprehensive evaluation of various hazards that impact their territories.

In the context of post-mining landscapes, conventional environmental policies often encounter challenges due to the lack of operational and accessible tools. The proposed DSS seeks to bridge this gap by catering to a diverse user base, including citizens, scholars, associations, and public bodies.

The DSS streamlines the acquisition, management, and processing of both static and dynamic data, providing web-accessible data visualization. Customized for post-mining multi-hazards, this tool contributes to enhanced decision-making by generating data, statistics, reports, and maps for various EU areas of interest. Validation is obtained through a case study of abandoned coal mine (France), this validation demonstrates its capabilities. This paper showcases the practical application of the DSS in North Rhine Westphalia offering valuable insights to address the intricate challenges posed by post-mining hazards.

How to cite: Bouaziz, M., Haske, B., Al Heib, M., and Benndorf, J.: A GIS-Based Decision Support System for Multi-Hazard Assessment in Post-Mining Regions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3065, https://doi.org/10.5194/egusphere-egu24-3065, 2024.

EGU24-3957 | ECS | Posters on site | ERE4.5

Comprehensive analysis and risk assessment of tailings storage facilities in China  

Chenxu Su, Nahyan M. Rana, Stephen G. Evans, Bijiao Wang, and Shuai Zhang

The historical failures of Tailings Storage Facilities (TSFs) in China have led to severe downstream consequences, encompassing loss of life, economic damage, and environmental contamination. Despite these consequences, the comprehensive documentation and quantitative evaluation of TSFs in China have been notably lacking. The existing records of TSFs are incomplete, and there is a deficiency in accurately assessing the frequency of their failures. This gap in knowledge has been a significant obstacle in effectively assessing and mitigating risks associated with TSFs. Our research involved compiling and analyzing new databases, shedding light on the historical failures and current status of TSFs in China. We uncovered 143 TSF failure incidents between 1957 and 2022. This figure largely exceeds the approximately 20 failures reported in earlier studies, highlighting a critical underestimation in past assessments. The human and economic damage of these incidents has been considerable, with 840 lives lost, 1,416 houses damaged, and 28,923 individuals adversely affected. Furthermore, the total volume of tailings released in these failures surpassed 12.7 million m3. A notable observation from our study is that about 75% of these failures involved tailings flowing into water bodies, exacerbating environmental pollution significantly. Our study also presents an in-depth statistical analysis of the magnitude and frequency of these failures. We found that the average return period for TSF failures in China, resulting in at least 10 fatalities, is approximately every five years. For failures with released volumes exceeding 1 million m3, the average return period extends to about 16 years. In addition to historical data, we include a comprehensive review of current TSFs. Our review confirms that there are 14,217 existing TSFs in China alone, leading to an estimated cumulative failure rate of approximately 1%. Our work further includes the development of a supplementary database encompassing 1,853 TSFs, providing essential statistics such as storage volume and dam height. This database is a crucial tool for ongoing and future risk assessments. Applying our database-driven, regionally-simplified risk assessment approach, we conducted a case study in Jilin Province. The results are concerning, indicating 11 TSFs bearing intolerable risks, among which the most hazardous TSF presents a potential loss of life estimated at 175 individuals. Our study offers the most comprehensive overview of TSF failures and their implications in China to date. The extensive scope of this research bears substantial implications for prospective nationwide utilization, particularly in the enhancement of risk assessment methodologies and the enforcement of efficacious mitigation measures for TSFs in China.

How to cite: Su, C., Rana, N. M., Evans, S. G., Wang, B., and Zhang, S.: Comprehensive analysis and risk assessment of tailings storage facilities in China , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3957, https://doi.org/10.5194/egusphere-egu24-3957, 2024.

EGU24-5645 | Posters on site | ERE4.5

Sensor-based Multi-Level Analysis of Ferronickel Furnace Slag: Exploring Economic Opportunities    

Feven Desta, Oscar Kamps, and Mike Buxton

The ever-growing demand for mining products has led to the extraction and processing of large volumes of materials, resulting in the production of significant amounts of mine waste. While the composition of mine waste materials can vary and may cause environmental impacts, they can also be a valuable source of raw materials to meet the current and future mineral demand. The efficient re-mining of minerals of economic interest from mine waste materials (such as slag) requires accurate and reliable estimation. This can be achieved using state-of-the-art sensor technologies coupled with advanced data analytics. Such technologies include laser-induced breakdown spectroscopy (LIBS), x-ray fluorescence (XRF), short-wave infrared (SWIR) and Fourier transform infrared spectroscopy (FTIR). This study evaluates the usability of LIBS, FTIR, SWIR, and XRF technologies for the characterization of Ferronickel slag materials at a multi-level. Methodological approaches were developed to assess the usability of each technique for the identification, classification, or semi-quantification of the target elements (such as Ni, Ti, Pb, and Cr) in the analyzed samples. The results demonstrate that the use of the techniques enabled a comprehensive compositional analysis of slag materials. Moreover, the findings suggest that such an approach could promote sustainable mining practices by providing valuable insights into the potential economic benefits of reusing slag materials for secondary recovery. Such an approach could contribute to reducing the possible environmental impact of waste and could enable achieving a circular economy.

How to cite: Desta, F., Kamps, O., and Buxton, M.: Sensor-based Multi-Level Analysis of Ferronickel Furnace Slag: Exploring Economic Opportunities   , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5645, https://doi.org/10.5194/egusphere-egu24-5645, 2024.

EGU24-5800 | Orals | ERE4.5

Macro- to nanoscale mineral relationships in mining wastes of the As–Sb–Tl–Au Allchar mine, North Macedonia 

Tamara Đorđević, Michael Stöger-Pollach, Sabine Schwarz, Goran Tasev, Todor Serafimovski, Ivan Boev, and Blažo Boev

In the mining waste dumps and tailings of the former As–Sb–Tl–Au Allchar deposit, North Macedonia, secondary oxides and oxy-salt minerals partially control the mobilization of arsenic (As), antimony (Sb) and thallium (Tl). Depending on the pH condition and the proportion of primary sulfide and sulfosalt minerals, we have observed two major scenarios for the retention of As, Sb and Tl through secondary minerals.

We have investigated three dozens of solid samples from the profiles and excavation holes at the three sites of former Alchar mine, analyzed them for their major and minor chemical elements, and characterized them for their mineralogical composition, with a special focus on Tl-secondary minerals at the nano- to centimeter scale.

At the Tl- and As-rich Crven Dol locality, As and Tl dissolved during weathering under circumneutral to slightly alkaline conditions are precipitated as micaceous crystals of poorly crystalline to amorphous thallium arsenates, forming porous aggregates up to 100 µm. These Tl arsenates are intergrown with dolomite and Ca-Fe-arsenates and appear as two different phases. In the first, more common phase Tl:As ratio range from ca. 2.1 to 4.1. In the second, Tl-richer phase, the Tl:As ratio varies from 5.1 to 8.4. In the waste dumps showing acidic pH-values common Tl precipitate is dorallcharite [TlFe3+3(SO4)2(OH)6]. Tl is also accumulated in Mn-oxides (up to 3.6 at.%), pharmacosiderite (up to 0.9 at.%), and jarosite-group minerals (up to 0.9 at.%).

The orpiment-rich tailings are mostly composed of orpiment, quartz, realgar and scorodite, followed by gypsum and kaolinite-group minerals. Realgar and orpiment are the major As-sources and Tl-sulfosalts lorándite, fangite, and raguinite are the primary Tl-sources. The most common Tl-bearing precipitate is dorallcharite mostly embedded in scorodite. Tl is also accumulated in Mn-oxides (up to 5 at.%) and thalliumpharmacosiderite, TlFe4[(AsO4)3(OH)4]·4H2O.

In the deposit is Sb-rich central region, the primary Tl sources are sulfosalts such as fangite, lorándite, and pierrotite, while stibnite is the primary Sb source. Tl dissolved during weathering under circumneutral conditions is reprecipitated as avicennite, Tl2O3, and tiny, fibrous Tl-bearing Mn-oxides (up to 8.5% Tl). Furthermore, tiny spherulitic aggregates (up to 3 µm) of a Tl-Sb-oxide (a new mineral species) have been found intergrown with quartz, muscovite, and minor dolomite. TEM-based EBSD on Tl-Sb-oxide particles confirmed that the Tl-Sb-oxide is crystalline, and EDS-line and area scans confirmed a Tl:Sb ratio of 2.5, indicating that Tl enters the crystal structure of the new Tl-Sb oxides rather than being hosted in the nanophase.The oxidative weathering of Tl-bearing metal-sulfides generates both nano- and microcrystalline Tl-minerals.

Our future investigation focuses on the formation and dissolution of these phases and will offer a much deeper understanding of the mechanisms of mineral association formation.

Financial support of the Austrian Science Fund (FWF) [P 36828-N] is gratefully acknowledged.

How to cite: Đorđević, T., Stöger-Pollach, M., Schwarz, S., Tasev, G., Serafimovski, T., Boev, I., and Boev, B.: Macro- to nanoscale mineral relationships in mining wastes of the As–Sb–Tl–Au Allchar mine, North Macedonia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5800, https://doi.org/10.5194/egusphere-egu24-5800, 2024.

EGU24-7632 | ECS | Orals | ERE4.5 | Highlight

Environmental monitoring of pollution at legacy mines in Greenland using portable X-ray Fluorescence Spectrometry (pXRF) 

Christian Frigaard Rasmussen, Christian Juncher Jørgensen, Jens Søndergaard, and Anders Mosbech

As the world’s need for raw materials increases, more mines are planned to be established in the Arctic. The Arctic provides a unique and challenging environment for mining operations and introduces concerns for the potential spread of pollution. Arctic environmental conditions linked to wind- and waterborne pollution transport such as hydrology, precipitation, temperature, windspeed and wind direction vary markedly throughout the year and the environment is sensitive to anthropogenic influence.

In Greenland, several legacy mines provide testimony to how pollution still affects the sensitive Arctic environment. These legacy mines serve as valuable study sites that can improve future predictions on environmental consequences of mining operations in Greenland and other areas in the Arctic. Environmental studies at legacy mine sites in Greenland have previously focused on the leaching of pollutants into the marine environment and little is known about the spatial distribution of pollution in the terrestrial environment at these sites.

In the current study, we present preliminary data from an environmental survey at the Blyklippen legacy mine. Blyklippen was a lead and zinc mine in East Greenland that operated between 1956-1963. Mining operations caused substantial pollution of lead (Pb), zinc (Zn), and other heavy minerals such as cadmium (Cd), barium (Ba) and copper (Cu), still measurable today. The primary sources of pollution today are the tailings storage facility and remains of ore concentrate spills along the haul road and at the quay areas at the harbor. Pollution is dispersed from these sites into the surrounding environment by wind and water.

The aim of the current study is to investigate and map the spatial distribution of heavy metals in the environment surrounding the Blyklippen legacy mine using both field measurements by portable X-Ray Fluorescence spectrometry (pXRF) on depth specific sediment samples at in situ conditions and laboratory measurements on freeze-dried samples to investigate the effect of soil moisture on the accuracy of the field screening. Field measurements were conducted using short measurement times of 5-10 seconds, whereas laboratory measurement times were 180 seconds.

A total number of 995 discrete sediment samples were collected over 10 days at the Blyklippen mine site and surrounding area of Mestersvig from 178 sampling locations at depth intervals of 5 cm. Our results demonstrate the effectiveness of pXRF as a field measurement tool for identifying the spatial delineation of soil pollution by comparing in situ measurements against pre-defined natural background values for heavy metals such as Pb and Zn. Comparison between Pb and Zn concentrations measured in the field versus in the laboratory on freeze-dried samples showed a good agreement for mineral soils. On organic and/or wet samples, field concentrations were underestimated for some elements.

Overall, the approach shows that a fast and cost-effective large-scale field survey at legacy mines is obtainable using pXRF, enabling an effective identification of pollution ‘hotspots’ directly in the field. In combination with geostatistical mapping, the approach can improve the overall accuracy of environmental monitoring and mapping of pollution with enhanced environmental protection at both legacy, recent and future mines.

How to cite: Rasmussen, C. F., Juncher Jørgensen, C., Søndergaard, J., and Mosbech, A.: Environmental monitoring of pollution at legacy mines in Greenland using portable X-ray Fluorescence Spectrometry (pXRF), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7632, https://doi.org/10.5194/egusphere-egu24-7632, 2024.

EGU24-8042 | ECS | Posters on site | ERE4.5

Origin of Rare Earth Elements in Acid Mine Drainage: Mineralogical Insights from the Iberian Pyrite Belt (SW Spain) 

Rafael León Cortegano, Francisco Macías, Carlos R. Cánovas, Rafael Pérez-López, Ricardo Millán-Becerro, Jonatan Romero-Matos, Laura Sánchez-López, and José Miguel Nieto

The Iberian Pyrite Belt (IPB), located in the SW of the Iberian Peninsula, is one of the largest polymetallic massive sulfide provinces in the world. Historical mining activity in the area has left a significant legacy of mine residues, including 90 abandoned mines and more than 1.000 ha of waste rock dumps and tailings. Therefore, large volumes of Acid Mine Drainage (AMD) are produced due to oxidation of pyrite-rich residues exposed to atmospheric conditions, which end up in the Tinto and Odiel rivers and subsequently into the ‘‘Ría de Huelva’’ estuary (SW Spain), polluting these water environments. During the passive treatment of AMD with Dispersed Alkaline Substrate (DAS) technology, sequential precipitation of Fe3+ as schwertmannite and Al as basaluminite occurs, and Rare Earth Elements (REE) are preferentially concentrated within the Al-rich precipitate layer. This could be an interesting alternative source of REE, given that AMDs of the IPB are enriched in middle REE (MREE) and heavy REE (HREE). A rough estimation of the REE potential of these AMD sources, based on 40 DAS plants operating in the Odiel basin with variable content of REE, will be the production of 11 kton/year of basaluminite containing 21 ton/year of REE2O3 with grade of 0.19%. However, the origin of REE in AMD is not well understood. This work examines the concentration and pattern of REE in AMD, ore bodies, and country rocks in two representative mining areas of the IPB: Perrunal and Poderosa mines. Leaching experiments were conducted on sulfide ores and host rocks under simulated AMD formation conditions, and the results were compared with the AMD formed in these two mining areas. The preliminary results indicate that the host rocks (felsic and mafic volcanics and shales) are the primary source of REE in the AMD. A mineralogical and chemical study of the country rocks in Perrunal and Poderosa mines reveals that secondary phosphates and carbonates contain the highest REE content, which are also soluble under acidic conditions. REE-rich monazite-type is systematically present in felsic volcanics and shales in both mining areas. HREE-rich xenotime-type is also present in most felsic volcanics, while REE-rich carbonates (mainly parasite-type) are present in carbonate-rich shales from the Perrunal mine. Other minor REE-bearing minerals, such as apatite and zircon, have been identified in the host rocks. However, due to their lower abundance and solubility under acidic conditions, they are not considered an important source of REE in the AMDs of the studied mining areas. Finally, the petrographic evidence shows a selective leaching of these REE-bearing phosphates and carbonates which highly supports their involvement as the main source of REE in AMD.

Acknowledgements: This work is part of the I+D+i TRAMPA project (PID2020-119196RB-C21), funded by MCIN/AEI/10.13039/501100011033/.

How to cite: León Cortegano, R., Macías, F., R. Cánovas, C., Pérez-López, R., Millán-Becerro, R., Romero-Matos, J., Sánchez-López, L., and Nieto, J. M.: Origin of Rare Earth Elements in Acid Mine Drainage: Mineralogical Insights from the Iberian Pyrite Belt (SW Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8042, https://doi.org/10.5194/egusphere-egu24-8042, 2024.

EGU24-8964 | Orals | ERE4.5

Delineation of mine tailings by ambient noise horizontal-to-vertical spectral ratio method 

Ayse Kaslilar, Zbigniew Wilczynski, Christopher Juhlin, and Mehrdad Bastani

The increasing need for mineral resources and critical rare earth elements (REE) due to the transition to clean energy has attracted interest in mine wastes as they may contain significant amounts of REE that were not of interest in the past but are today. Detailed knowledge about the 3D geometry and size of the waste deposits and their mineral content is important to understanding whether waste tailings can serve as a secondary resource, contributing to the energy transition, sustainability, and the circular economy, and promoting recycling.  Geophysical methods can provide information on the geometry, and help to characterize and estimate the size of the mine waste. In the last two decades developments in sensor and computational technology have enabled cost-effective and environmentally friendly seismic ambient noise methods to be widely applied for imaging the subsurface. Among others, one of the ambient noise methods is the horizontal-to-vertical spectral ratio (HVSR) method, which is an efficient technique widely used for site characterization, estimating the thickness of overburden above bedrock, monitoring landslide, and examining the stability of tailing dams.

In this study, ambient noise data and the HVSR method are used to estimate the thickness and delineate the 3D geometry of mine tailings. We use three-component (3C) ambient noise data that we collected with 50m spacing between the sensors and profiles in one of the non-active mine tailings of Nordic Iron Ore in Blötberget, Sweden, which might be a potential resource for REE.  We process the 3C data and obtain the fundamental frequency at each receiver location. Moreover, one-component ambient noise data that we collected along two perpendicular profiles with a receiver spacing of 5m are used to estimate the surface wave velocity. Combining the fundamental frequency and velocity information, we calculate the depth of the contrasting interface. We show our preliminary results obtained from ambient noise data and compare them with the previous results from the radio magnetotelluric measurements conducted by Geological Survey of Sweden.

This work is part of a project supported by the Geological Survey of Sweden. We gratefully acknowledge this support.

How to cite: Kaslilar, A., Wilczynski, Z., Juhlin, C., and Bastani, M.: Delineation of mine tailings by ambient noise horizontal-to-vertical spectral ratio method, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8964, https://doi.org/10.5194/egusphere-egu24-8964, 2024.

EGU24-9303 | Posters on site | ERE4.5

Recycle of quarry byproducts for producing a new Zn fertilizer 

Giulio Galamini, Daniele Malferrari, Fabiana Altimari, Silvia Orlandi, and Luisa Barbieri

Zinc (Zn) is a crucial micronutrient for plants, related with tolerance against diseases. When crop demand exceeds Zn availability in the soil, using Zn­-fertilizers becomes necessary (biofortication), however, even in foliar application, soluble Zn salts are mostly used, which are prone to leaching and consequently exhibit limited uptake by plants.

In response to this challenge, a novel controlled-release formulation, utilizing mine wastes as carrier, was developed, involving an energy-efficient process with ambient temperature and pressure, and a reaction time of approximately 8 hours.

Formulations were prepared by mixing a zeolite-rich (clinoptilolite) tuff with 2 quarry by-products, namely lapillus and pumice, using different dosages. We conducted studies on the kinetics of Zn adsorption and release, ultimately identifying the most effective mixture which comprised 70% zeolite-rich tuff and 30% pumice.

To assess the effectiveness, a fertilization test was performed via foliar application in Vitis vinifera, aiming to evaluate the Zn coverage, and the persistence of the product against simulated rainfall, in comparison with conventional ZnSO4 fertilizer.

The test confirmed greater Zn resistance to rain leaching, also suggesting potential for reducing treatment dosages, thereby mitigating environmental-related impacts. Moreover, the presence of 30% pumice would allow significative reuse of mining byproduct.

Project funded under the PNRR–M4C2INV1.5, NextGenerationEU-Avviso 3277/2021 -ECS_00000033-ECOSISTER-spk1

 

How to cite: Galamini, G., Malferrari, D., Altimari, F., Orlandi, S., and Barbieri, L.: Recycle of quarry byproducts for producing a new Zn fertilizer, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9303, https://doi.org/10.5194/egusphere-egu24-9303, 2024.

EGU24-10941 | Posters on site | ERE4.5

Cost – Benefit Analysis through Stochastic Risk Assessment on Mining Waste Management 

Evangelos Machairas, Emmanouil Varouchakis, and Michail Galetakis

Cost Benefit & Bayesian Analysis for Mining Waste Management contributes positively to developing an alternative methodology that could be implemented on an industrial scale. Two case scenarios are examined. The first scenario refers to the presentation of mining activities without 3R’s policy (reduce, recover, reuse wastes) and non-implementation of environmental protection measures. The second scenario refers to the presentation of mining activities with full implementation of environmental protection requirements by a closed system of industrial units for metal recovery and avoiding free disposal of tailings in soil areas. Considering a) each project’s aim and scope, b) legislative requirements for environmental protection, and c) escalation of penalty cost for non-compliance with the corresponding legislation, the total cost for each case scenario is extracted. Cost-benefit analysis (CBA) evaluates the sustainability of each case scenario by its Financial Risk.

The scope of this paper is to ensure the adaptability of the CBA appraisal tool to each similar subject of study, in which the lowest Financial Risk indices characterize optimal business decisions. CBA’s evaluation involves each case scenario’s parameters converted into monetary terms. CBA’s extracted results are calibrated through Bayesian Analysis to provide more accurate Financial Risk (FR) estimation. The physical meaning of Bayesian Analysis’s provided calibration to the CBA is to obtain the ability to implement stochastic risk in realistic conditions.

How to cite: Machairas, E., Varouchakis, E., and Galetakis, M.: Cost – Benefit Analysis through Stochastic Risk Assessment on Mining Waste Management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10941, https://doi.org/10.5194/egusphere-egu24-10941, 2024.

EGU24-11299 | ECS | Posters on site | ERE4.5

Developing PRIME Technology for Enhanced Coal Tip Assessment: Innovations in Continuous Geoelectrical Monitoring and Landslide Decision Support 

Yin Jeh Ngui, Adrian White, Harry Harrison, Judith Porter, James Boyd, Phil Meldrum, Paul Wilkinson, Oliver Kuras, Jonathan Chambers, and Sam Deeley

Disused coal tips formed by waste materials from coal mining activities can become unstable over time. Landslides or avalanches of coal waste can occur, especially during heavy rainfall or by other environmental factors, leading to significant safety hazards for nearby residents and infrastructure. The Welsh Government Coal Tip Safety Taskforce has recently identified over 2,500 disused coal tips in Wales potentially posing a risk, following a significant landslip in Tylorstown after the 2020 storms. Ongoing climate change further destabilises these legacies of past mining activities, posing great challenges to land management and hazard remediation, as instability within the coal tip can be invisible to surface surveys and inspections.

Wattstown in the Rhondda Cynon Taf County Borough was identified as a preferred location for deploying long-term 4D geoelectrical monitoring, with the aim of observing the moisture dynamics between a heavily vegetated basin area upslope of the coal tip (where a previous landslip has occurred) and the downslope tip materials. A BGS-designed Proactive Infrastructure Monitoring & Evaluation (PRIME) system has been deployed here to characterise this site using eight 32-electrode arrays. PRIME is a low-cost, low-power, non-invasive 4D geo-electrical imaging technology designed for near-real-time infrastructure monitoring.  The eight ERT sensor arrays are arranged so that four arrays form two long 2D survey lines to monitor the main slope in directions perpendicular to each other, while a further five arrays cover the landslip region in a 3D configuration, in which one of the arrays is common between the linear and the grid configuration. A full daily measurement schedule allowing for ground motion tracking has been implemented since Mid-2023. Measured data is transferred daily to the BGS servers, and system diagnostics reports are automatically generated to confirm the recent monitoring status and performance of the PRIME system.

The baseline resistivity model shows a lower resistivity layer with a variable thickness of 0 - 5 m covering the whole monitored area. This layer is interpreted as spoils that have been deposited and subsequently reprofiled. Our observation also matches with the presence of high clay contents found in the hand-augered soil. Below the reprofiled spoils resistivity values increase significantly, likely to be underlying bedrock that is composed of sandstone with interbedded layers of coal and silt.

Time-lapse inversion revealed the influence of effective precipitation on the moisture dynamics of the coal tip. Several anomalies were observed within the gradually decreasing resistivity distribution in the near-surface. Along the line perpendicular to the slope, larger low-resistivity features are observed in both the ditches that run parallel to the slope. This could be the result of preferential infiltration in these areas and the ponding of surface water. In the rotational landslip area, PRIME monitoring data has identified what is potentially a preferential flow path from 5 m to 10 m below ground level.

Through continuous monitoring of the disused coal tip, the PRIME system demonstrated its capability for enhanced coal tip assessment, detecting critical hydrogeological processes through minimally-invasive subsurface imaging. Ongoing work aims to establish in-situ petrophysical relationships.

How to cite: Ngui, Y. J., White, A., Harrison, H., Porter, J., Boyd, J., Meldrum, P., Wilkinson, P., Kuras, O., Chambers, J., and Deeley, S.: Developing PRIME Technology for Enhanced Coal Tip Assessment: Innovations in Continuous Geoelectrical Monitoring and Landslide Decision Support, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11299, https://doi.org/10.5194/egusphere-egu24-11299, 2024.

Sulfide minerals present in mine waste, upon oxidation by oxygen and water, can lower the pH, leading to increased metal solubility. This study focuses on mine waste containing sulfide mineral, utilizing fuel cell technology to recover valuable resources. The aim is to explore the potential conversion of mining by-products into valuable energy and resources, addressing environmental impact and transforming mining waste into a valuable asset. The electrochemical oxidation of pyrite (FeS2) (ΔG0 = -27.15 kJ/mol) is induced through electrode installation, with the reaction facilitated by employing electrodes. In this process, pyrite acts as an electron donor, and oxygen, mediated by the electrode, acts as an electron acceptor. The cathode is designed to induce the oxidation of pyrite (Pyrite→Fe3+), while the anode, exposed to oxygen in the air, promotes the reduction of oxygen (O2→H2O). Pyrite (150-250 μm in diameter) was placed in the anode cell containing 125 mL of anolyte (distilled water adjusted to pH 2.0 with hydrochloric acid), and the cathode cell was exposed to air. After 4 weeks of reaction 23 mg of pyrite was dissolved leaching 0.73 mM of Fe, and generating 4.1616×10−7 W of power. In the further study the fuel cell technology will be applied to utilize sulfidic mining residues (XRD analysis result: FeS1.6Se0.4 42%, FeS2 14%, Mg2CaWO6 12%, etc.), generated during the ore beneficiation process at a tungsten mine in Yeongwol, Gangwon Province, South Korea, for the recovery of energy and valuable metals.

How to cite: Ju, W. J. and Nam, K.: Electrochemical conversion of sulfide mineral-containing mine waste for energy and resource recovery using fuel cell technology, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12537, https://doi.org/10.5194/egusphere-egu24-12537, 2024.

EGU24-14563 | Orals | ERE4.5

Reimagining Australia's mine waste: New resources, new challenges 

Anita Parbhakar-Fox, Laura Jackson, Kamini Bhowany, Rosie Blannin, Allan Gomes, and LeXi K'ng

Meeting the needs of the energy transition is a once-in-a-generation challenge like no other before. To meet the projected metal demand to support things, the global community will produce increased volumes of mine waste requiring best practice management. Mine waste is suspected to be a host of critical metals and minerals (i.e., cobalt, indium, REEs, Ga and Ge have typically been by-products since concentrating in waste streams). If identified as significant resources of critical metals, remining waste can support Australia’s effort to adopt circular economy principles, a notable socio-economic driver.

Whilst this sounds relatively straightforward, practical investigations show this is anything but. From sampling to metal recovery, mine waste materials are complex and heterogenous originating, in some cases, from multiple ore sources, processed by different methods, and eventually subjected to weathering under changing climatic conditions. Therefore, multi-scale multidisciplinary characterisation is required to truly develop a valorisation process which not only recovers critical metals and minerals, but also substantially reduces any associated environmental legacy issues and mining footprints.    

In collaboration with the QLD, NT, NSW and SA State Governments and Geoscience Australia mine waste (i.e., tailings, slag, waste rock and metallurgical residues) at historical and operational mines across the country have been sampled (n= 50 of 77: 2019-2024). Highlights so far include potential for Co resources in QLDs NW Minerals Province with metallurgical studies now being conducted to recover Co from pyrite.  Indium, hosted in a range of sulfides, sulfosalts and cassiterite has been recognised in greisen and VHMS mine waste, whilst Sb (and REE) enrichment has been identified in the sampled NT. New investigations are underway to better understand SAs waste with desktop studies suggesting Ni, REEs and Mn fertility. 

 

Whilst these data will ultimately feed into the national Mine Waste Atlas being developed by Geoscience Australia, opportunities to manage the new waste streams are being explored. With new markets coming online seeking feedstocks which are more enviro-ethically sourced. However, the challenge remains, how to ensure policies are in place to support these activities, whilst ensuring that the right technologies to support valorisation are accessible. As global communities align to tackle these hurdles, mine waste transformation looks certain to be the business model of the future. 

  

How to cite: Parbhakar-Fox, A., Jackson, L., Bhowany, K., Blannin, R., Gomes, A., and K'ng, L.: Reimagining Australia's mine waste: New resources, new challenges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14563, https://doi.org/10.5194/egusphere-egu24-14563, 2024.

EGU24-14982 | Posters on site | ERE4.5 | Highlight

Analysis of ground movements in the post-mining area of the lignite mine “Babina” (W Poland) 

Natalia Walerysiak, Jan Blachowski, Jarosław Wajs, and Paulina Kujawa

Post-mining areas require constant monitoring due to the risk of secondary ground movements of a continuous or discontinuous nature. This study focuses on the analysis of ground movements in the post-mining area of the “Babina” mine in Western Poland. The complex nature of the “Muskau Arch” glaciotectonic area, subjected to both underground and open pit mining, further complicates the understanding and monitoring of these movements.

The study site was subjected to precise levelling monitoring between 2020 and 2023, and the results of five measurement campaigns form the basis of the analysis, with the first measurement being the reference for the subsequent ones. For this purpose, a geodetic monitoring network was established to cover key locations in the “Babina” mine area. The network was made up of 99 control points set-up as concrete pillars with metal control bolts and was connected to 4 reference benchmarks of the national levelling network situated beyond the post-mining area. In addition, 7 local research networks have been established in specific study sites. The levelling measurements were carried out using geodetic precision levelling. The total length of the levelling lines was approximately 36 km. The ground movements recorded between the first (initial), carried out in May 2020, and the last measurement campaign, in September 2023, range from -5.58 mm to +4.97 mm. Ground movements in the specific dense networks range from -39.46 mm to +115.39 mm.

Three interpolation methods were used to obtain continuous maps of the ground movements from discrete levelling observations: Inverse Distance Weighted, Radial Basis Function and Ordinary Kriging. The latter technique produced the smallest root-mean-square errors assessed with the cross-validation technique. In the result, we obtained 24 maps representing elevation changes between the first and the last measurement, as well as maps representing movements between consecutive measurements.

The maps of ground movements were used to identify areas of statistically significant displacements and to analyse the evolution of these displacements over time and in relation to the extent of past underground and open-pit mining activities and current land use. The results indicate present-day activity of the ground in the post-mining area that varies in the magnitude and direction of movements in different parts of this complex area. The observed seasonal fluctuations may indicate relationship of benchmark movements with periodic change of ground water level and the effect of climate change.

Our findings confirm the presence of ground movements in post-mining area five decades after the end of mining activity and of varied nature, as well as substantiate the need for further investigation of this activity in the study area. These should include detailed analysis of the relation between groundwater level and benchmark heights and correlation of movements with the extent of shallow underground mining.

The research has been financed from the OPUS National Science Centre projects grant no. 2019/33/B/ST10/02975 and grant no 2021/43/B/ST10/02157.

How to cite: Walerysiak, N., Blachowski, J., Wajs, J., and Kujawa, P.: Analysis of ground movements in the post-mining area of the lignite mine “Babina” (W Poland), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14982, https://doi.org/10.5194/egusphere-egu24-14982, 2024.

EGU24-15004 | ECS | Posters on site | ERE4.5

Flash Water Detection in Mining Areas Using Satellite Imagery and Meteorological Data  

Aleksandra Kaczmarek

Detection of temporary surface water is a critical aspect of monitoring the impact of mining on the environment and the impacts of underground gas storage (UGS) sites in particular. Recent years have been very dynamic for the energy sector, as increasing energy demand and the progression of global warming require constant improvements and changes. The general trend is to move away from conventional energy sources. However, green fuels require large storage volumes, which can be provided by geological storage. It can also be used to trap CO2 and thus contribute to the reduction of CO2 emission into the atmosphere.

Injection and withdrawal of gases in underground magazines affect the environment in a number of ways. Pressure changes and corresponding stress induce seismic activity, surface subsidence, and uplift. Gas leakage poses a risk to soil, water and air contamination. Therefore, it is necessary to treat UGS sites together with their surroundings in a holistic manner considering all potential impacts. The study UGS site is located in northern Poland. Natural gas is stored in salt caverns. The terrain to the north of the facility is of particular interest, as it is agricultural land with an old drainage system. It has not been maintained for years and the water reoccurs periodically. Low elevation and short distance to the sea favour flash flooding, which might be reinforced by UGS induced surface movements. The purpose of the test study is to detect surface water with a remote sensing based approach and establish the correlation between rainfall and surface water dynamics.

Satellite remote sensing provides a valuable means of continuous and large-scale monitoring of surface water dynamics. Spectral bands and indicators enable the discrimination of various types of land cover and their changes, including the appearance of flash water. The proposed methodology involves time-series analysis of open satellite data (Sentinel-2), spatial statistics, and comparative analysis of selected indicators and spectral bands used for water detection. Additionally, daily precipitation data from a local meteorological station were integrated into the analysis to evaluate the accuracy of surface water detection. Regression analysis has been done to analyse the relationship between the accumulation of water and rainfall, and therefore assess whether the indicators tested are suitable. 

The test analysis covers the period August 2015 - December 2023. The area of interest is cultivated. Crop fields, after harvest and before the vegetation season, are mostly bare soil, which can be mistakenly interpreted using basic plant moisture indices. Therefore, more combinations were tested and verified with rainfall data. By incorporating meteorological data, we aim to establish a more comprehensive understanding of the temporal variability in the presence of surface water near the gas storage site. The findings of this study contribute to the development of a complex monitoring system at a UGS site.

The research has been carried out under the project acronym CLEAR (grant no WPN/4/67/CLEAR/2022) financed from the Polish National Centre for Research and Development.

How to cite: Kaczmarek, A.: Flash Water Detection in Mining Areas Using Satellite Imagery and Meteorological Data , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15004, https://doi.org/10.5194/egusphere-egu24-15004, 2024.

EGU24-17054 | Orals | ERE4.5

Exploration and reevaluation of a tailing storage facility from a high-sulfidation epithermal gold deposit 

Petya Gutzmer, Kai Bachmann, Raimon Tolosana-Delgado, Laura Tusa, Cecilia Contreras, Philipp Büttner, and Jens Gutzmer

Reevaluating tailings material originating from a high-sulfidation epithermal gold deposit has unveiled the potential for a holistic remining endeavour. The primary objective of this operation would be the mitigation of minerals containing penalty elements, specifically sulphur in pyrrhotite, a major contributor to acid mine water drainage, alongside the concentration of precious elements like gold. Furthermore, exploring the applicability of the silicate fraction for industries such as ceramics, glass, and geopolymer production has been considered.

To accomplish these objectives, an initial drill core campaign featuring six drill holes was executed, accompanied by a thorough material characterization using automated mineralogy, geochemical assays, and hyperspectral analysis. The subsequent step involved a geometallurgical domaining process based on 64 geochemical assays, particle size measurements, and mineralogy assessments. A Mahalanobis distance hierarchical cluster analysis was employed to differentiate domains, and predictions for these domains were extended to all hyperspectral imaging samples.

The outcome of this comprehensive approach revealed the delineation of four distinct domains, each characterized by variations in modal mineralogy and trace elemental contents. This strategic analysis provides valuable insights into the heterogeneity of the tailings material, laying the groundwork for targeted interventions to address environmental concerns and maximize the extraction of valuable resources.

How to cite: Gutzmer, P., Bachmann, K., Tolosana-Delgado, R., Tusa, L., Contreras, C., Büttner, P., and Gutzmer, J.: Exploration and reevaluation of a tailing storage facility from a high-sulfidation epithermal gold deposit, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17054, https://doi.org/10.5194/egusphere-egu24-17054, 2024.

EGU24-17315 | Posters on site | ERE4.5

A Web-Based Tool for Assessing Sustainability in Secondary Raw Material Recovery Projects Using the UNFC Framework 

Soraya Heuss-Aßbichler, Laddu Bhagya Jayasinghe, Alireza Sobouti, Iman Dorri, and Juan Antonio Munizaga-Plaza

The increasing demand for raw materials in our society and the requirements for supply security in particular regarding the critical raw materials require the implementation of sustainable resource management in the sense of the best possible conservation of natural resources as well as the promotion of recycling and recovery of valuable materials from waste. In the mining sector, classification systems like CRIRSCO were introduced to communicate the viability of projects. In the realm of resource classification, the United Nations Framework Classification of Resources (UNFC) stands as a crucial tool, offering a principles-based approach to classifying the viability of any kind of resource development projects including renewable energy or groundwater. By systematically classifying projects based on their environmental, socio-economic, and technical aspects, the UNFC provides decision-makers with valuable insights for making choices regarding their viability and offers the opportunity to take sustainability aspects into account. A consistent evaluation and classification of projects according to the same premises as for primary raw materials can significantly contribute to the efficiency of initiatives for the recovery and recycling of secondary raw materials including mining waste. There is a Guidance[1] for the Application of the United Nations Framework Classification for Resources (UNFC) for Mineral and Anthropogenic Resources in Europe. However, it doesn’t include end-of-life products as anthropogenic resources. There are also no instructions on how to evaluate and classify SRM projects.

To bridge the gap, our focus has centered on the development of a web-based tool explicitly designed for the assessment of SRM recovery projects in line with the principles of the UNFC. A seven-stage approach was developed to streamline the evaluation process and by that, improve the accessibility and applicability of the classification system. Its design, features, and functionalities are tailored to ensure a user-friendly interface. Users are guided from the outset by defining the project and its systems boundaries, formulating the project’s objective and the context of evaluation, including the choice of the controlling factors, to carry out a thorough analysis of SRMs and thus align their initiatives with the principles of the UNFC. At the end, a template is available for reporting.

This poster presentation aims to emphasize the versatility and effectiveness of our web-based tool through a practical example, using a publication developed to classify a tailings storage facility in Germany. Through an interactive demonstration, the user-friendly interface, the power of customizable inputs, and the seven coordinated steps that guide users in assessing the feasibility and viability of secondary raw material projects will be discussed. Attendees will gain a deeper understanding of how the tool facilitates informed decision-making by providing a systematic approach to evaluating projects involving secondary raw materials, aligning with the principles of the UNFC.


[1] https://unece.org/sites/default/files/2022-11/UNFC%20GUIDANCE%20EUROPE-FINAL.pdf

How to cite: Heuss-Aßbichler, S., Jayasinghe, L. B., Sobouti, A., Dorri, I., and Munizaga-Plaza, J. A.: A Web-Based Tool for Assessing Sustainability in Secondary Raw Material Recovery Projects Using the UNFC Framework, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17315, https://doi.org/10.5194/egusphere-egu24-17315, 2024.

EGU24-17319 | Posters on site | ERE4.5

Converting mine shaft into compressed air energy storage – shafts screening and assessment 

Marcin Lutyński and Konrad Kołodziej

Increase in the share of renewables in the energy mix of European Union gained interest in the large scale energy storage technologies. One of the promising technologies is the Compressed Air Energy Storage (CAES) where in conventional approach compressed air is stored in the cavern. An alternative solution that was developed at the Silesian University of Technology is to use a post-mining shaft for adiabatic compressed air energy storage (A-CAES). Availability of post-mining infrastructure and large number of shafts in European coal basins (over 178 shafts only in the Upper Silesia Coal Basin) shows a significant potential of this solution. In order to select a proper shaft with a considerable volume a screening tool was developed that uses multicriteria analysis for an initial selection of shafts that could be used for this technology. This tool takes into account shaft depth, diameter, type of shaft collar lining, water inflow rates and other criteria that are important for safety and energy capacity of the system. The presentation shows results of analysis of the shafts screening tool and case study for one of the shaft located in Poland.

How to cite: Lutyński, M. and Kołodziej, K.: Converting mine shaft into compressed air energy storage – shafts screening and assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17319, https://doi.org/10.5194/egusphere-egu24-17319, 2024.

EGU24-17569 | Orals | ERE4.5

Certification systems for the ecological rehabilitation of mined areas 

Michail Galetakis, Emmanouil Varouchakis, Christos Roumpos, and Georgios Louloudis

Ecological reclamation of mined areas is a critical step in restoring environmental balance. Mining companies and operators are usually required to restore their sites to a condition that supports an agreed post-mining land use and to mitigate environmental and social impacts. To achieve rehabilitation approval, specific closure objectives and completion criteria must be defined to determine whether the necessary outcomes have been attained.  Certifications in this area typically focus on ensuring that reclamation processes meet certain standards and effectively restore the ecosystem. Some well-known certifications include the Society for Ecological Restoration (SER) certification and the International Standards Organisation (ISO) environmental management system certification. SER certification often assesses projects based on ecological integrity, historical and cultural considerations, and sustainable management. It ensures that reclamation efforts promote biodiversity, soil health and overall ecosystem resilience. On the other hand, older ISO certifications, particularly ISO 14001, focus on environmental management systems and ISO 26000 on social responsibility. While not specific to ecological reclamation, it provides a framework for organisations to develop and implement environmentally responsible practices. Recent ISO standards like 21795:2021 specify the framework and the processes involved in mine closure and reclamation planning for new and operating mines, and they also provide requirements and recommendations.  These certifications play a critical role in establishing credibility and ensuring that ecological reclamation efforts meet recognised standards. They also contribute to the broader goal of sustainable mining practices. This study examines the evolution of standards for the certification of rehabilitation of mined sites, reflecting the growing awareness of environmental impact and the shift toward sustainable practices.

How to cite: Galetakis, M., Varouchakis, E., Roumpos, C., and Louloudis, G.: Certification systems for the ecological rehabilitation of mined areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17569, https://doi.org/10.5194/egusphere-egu24-17569, 2024.

EGU24-19060 | ECS | Posters on site | ERE4.5

The bioleaching of metals from organic-rich black shale by Pseudomonas fluorescens 

Mateusz Wolszczak, Anna Potysz, and Grzegorz Lis

Biohydrometallurgy is known as one of techniques of beneficiation of metal ores, utilizing microorganism activity to enhance the extraction of metal ions from ore minerals. The method is widely known from its economic and environmental advantages in comparison to other beneficiation methods, i.e. pyrometallurgy. The development of biohydrometallurgy applications for the mining industry has continued since the eighties when several bioleach operations for low-grade copper ores and refractory gold concentrates have been commissioned. Although significant extraction rate, biological-induced leaching does not constitute main processing technique due to economic reasons, what drive researchers to searching novel ways to enhance the efficiency of metal recovery.

 

This research came with the idea of improving the efficiency of metal bioleaching by presence of dispersed organic matter naturally occurring in some rocks. Main hypothesis of the research assumes using dispersed organic matter as a source of organic carbon by heterotrophic bacteria that could further enhance dissolution of ore minerals. The idea came from both facts: consumption and metabolic utilization of dispersed organic matter by heterotrophic microorganisms and influence of consumed organic compounds on microbial activity e.g. secretion of siderophores (metal chelating compounds, crucial for solubilization metal ions and thus acceleration the metal leaching).

 

The examined rock is metalliferous-bearing shale enriched in dispersed organic matter (with average TOC parameter from few to even 30 wt.%). Two shale samples different in their metal and organic matter quantity were chosen for testing the hypothesis. The potential of black shale for bioleaching was examined through series of incubation experiments. Different experiment conditions were applied, involving both autotrophic (Acidithiobacillus thiooxidans) and heterotrophic (Pseudomonas fluorescens) bacteria and different medium compositions (with presence and absence of organic nutrient in particular).

 

The incubation experiment took place in a shaker incubator at a controlled temperatures for a period of five weeks. After the incubation experiment the leachates were collected and analyzed for the concentrations of eight metals: copper, lead, zinc, molybdenum, arsenic, nickel, cobalt and vanadium. The metal recovery percent features variation depending on shale sample, specific metal, and incubation condition. The highest metal recovery was achieved for heterotrophic bacterium in case of copper and molybdenum and for autotrophic one in case of arsenic, while rest of metals showed insignificant recovery. Lack of organic nutrients weakened the activity of P. fluorescens compared to bacterium supplied with organic nutrient, however metal leaching was still maintained.

How to cite: Wolszczak, M., Potysz, A., and Lis, G.: The bioleaching of metals from organic-rich black shale by Pseudomonas fluorescens, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19060, https://doi.org/10.5194/egusphere-egu24-19060, 2024.

EGU24-19879 | Posters on site | ERE4.5

Erosion rates estimates on a post-mining site 

Thomas Grangeon, Tur Raphaël, Louis De Lary de Latour, Florian Masson, and Cerdan Olivier

Mining waste serves as a significant example illustrating the transport of contaminants in association with rainfall, runoff, and erosion. Due to past or ongoing metal extraction activities, mining waste deposits are widespread across numerous countries. Rainfall events affecting these areas can lead to environmental concerns due to both liquid and particulate transfers. Acid mine drainage has been extensively researched in this context, illustrating the transfers linked to the liquid phase. Furthermore, rock crushing and high metal concentrations in the waste create materials with minimal cohesion and little vegetation cover, making them highly susceptible to surface erosion. As a result, mine wastes may also be particularly prone to contaminant transport in the particulate phase, although such transfers have received comparatively less attention than liquid transfers. Assessments of surface erosion caused by rainfall and runoff are still lacking in literature, which limits our comprehension and ability to model these processes in these unique environments.

We propose estimating erosion rates on a 3.8-hectare post-mining site located in central France. Given the high erosion rates, we opted to combine two distinct methodologies based on elevation differences: i) erosion pins for simple and reliable but localized estimates of erosion rates, and ii) differences in Digital Elevation Models (DEMs). In this study, the DEM was obtained using a novel handheld laser scanner. Both methods yielded results within the same range, indicating substantial erosion rates and thereby highlighting the significance of particulate transport. Depending on the local circumstances (e.g., tailings characteristics, tailing-to-stream connectivity), future studies should consider both liquid and particulate transport from post-mining sites to develop relevant mitigation strategies.

How to cite: Grangeon, T., Raphaël, T., De Lary de Latour, L., Masson, F., and Olivier, C.: Erosion rates estimates on a post-mining site, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19879, https://doi.org/10.5194/egusphere-egu24-19879, 2024.

EGU24-20090 | ECS | Posters on site | ERE4.5

Towards migration of fines within a soil matrix 

Shane Aulestia, Jasmina Toromanovic, and Jan Laue

Suffusion is an internal erosion mechanism observed in embankment dams, caused by washing out fine-grained particles within the dam core as a consequence of seepage with various hydraulic gradients. The initiation of internal erosion is conditional upon three primary factors: grain size distribution, stress conditions, and hydraulic gradient. Graded moraines, such as glacial tills, exhibit an increased susceptibility to suffusion when compared to other soil types used in dam construction. Many Swedish embankment dams in mining and hydropower industry were constructed with glacial till cores over 50 years ago, lacking specific guidelines related to grain size boundaries for core and filter materials. This deficiency has given rise to instances of internal erosion, therefore elevating safety concerns.

Previous research aimed to enhance dam safety by exploring the susceptibility of glacial till soils to suffusion. Silva (2022) reviewed existing methods for assessing soil susceptibility, comparing testing conditions, and presents an experimental study on critical hydraulic gradients for suffusion initiation in glacial till soils. Results indicate the critical hydraulic gradient depends upon testing conditions, including axial loading, the rate of gradient increase, and time intervals. Furthermore, it underscores the efficacy of Kenney and Lau (1985, 1986) method for assessing suffusion susceptibility. These insights offer valuable contributions to the assessment and mitigation of internal erosion in embankment dams, thereby addressing a significant safety concern within the Swedish dams infrastructure.

Silva (2022) has offered valuable insights into suffusion phenomena while the intricacies of erosion processes remain unclear, hindering the implementation of rehabilitation measures to ensure the longevity of embankment dams. A follow-up project utilizing the advantages of transparent soil seeks to further comprehend the migration of fines within a soil matrix. Transparent soils, emerging as a viable alternative with likely properties to sand and clays, consist of a two-phase medium by refractive index allow solids to represent the soil skeleton and a fluid solution to mimic pore fluids. Various solids, such as amorphous silica, silica gel, hydrogel, fused quartz, and laponite, have been employed in conjunction with fluid solutions, depending on the solid, as mineral oil and paraffinic solvent, calcium bromide brine, sucrose solution, or water.

Transparent soils offer the potential to replicate the behavior of glacial till cores employed in embankments, particularly those designed for the storage of tailings material in the mining industry, and water retention for hydropower. The applicability of these findings may address and enhance rehabilitation measures in such structures, which are imperative to mitigate potential socio-economic and environmental ramifications in the event of failure. Given the escalating global demand for mining resources and renewable energy, proactive measures are essential to predict long-term issues looking for a more sustainable and efficient construction methodologies to extend infrastructure lifespans.

How to cite: Aulestia, S., Toromanovic, J., and Laue, J.: Towards migration of fines within a soil matrix, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20090, https://doi.org/10.5194/egusphere-egu24-20090, 2024.

EGU24-20831 | Orals | ERE4.5

Post-mining earthquakes and changes in observed vertical ground displacements during the period of mine flooding  

Violetta Sokoła-Szewioła, Zbigniew Siejka, and Patrycja Jarczyk

The period of coal mine closures can be accompanied by many hazards, including the post-mining seismic hazard. Seismic phenomena, particularly during mine flooding, are felt by people, can cause minor or severe damage to buildings and affect shallow mine workings, and can cause reactivation of shallow mine workings in the form of sinkholes or other discontinuous deformations. It is therefore important to deepen the knowledge concerning these phenomena, particularly their relationship to surface deformations. This issue was the subject of a European research project with the acronym PostMinQuake financed by the Research Fund for Coal and Steel in 2020- 2023 (Grant Agreement No: 899192). The project involved the study of surface deformation in relation to registered post-mining earthquakes during the flooding of the Kazimierz- Juliusz coal mine. The research area was located in Poland in the area of the Upper Silesian Coal Basin. In this area, continuous monitoring of surface deformation was carried out for more than 2 years on single observation points using GNSS technology. The monitoring was carried out using an automatic GNSS monitoring system developed in the project. 

The paper presents the results of an analysis of the course of changes in vertical displacements at the above-mentioned points, in relation to the post-mining earthquakes registered during the study period. The analysis showed that in the case of more than 58% of the analyzed phenomena in the course of vertical displacements in the period associated with the occurrence of the post-mining earthquake, there were some regularities in the course of these displacements. It was found that, an increased uplift was observed prior to the occurrence of the event, in the next period of time, after the occurrence of the event, an increased increment in subsidence was generally observed, after that period, stabilization of the changes in vertical displacements was observed, as well as a slow increment of subsidence and/or the increment of uplifts. On this basis, it was concluded that there was a relationship between the observed course of displacements and the occurrence of post-mining earthquake. It was assumed that the significant increase in observed uplift can be a predictor of the occurrence of a post-mining earthquake.

 

How to cite: Sokoła-Szewioła, V., Siejka, Z., and Jarczyk, P.: Post-mining earthquakes and changes in observed vertical ground displacements during the period of mine flooding , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20831, https://doi.org/10.5194/egusphere-egu24-20831, 2024.

Through this study, a novel method for producing magnetic biochar from waste wood sourced from Acacia auriculiformis is achieved. Slow pyrolysis method of biochar was used for the conversion of waste wood which in turn proved to be more efficient than other procedures. Nanoparticles which were successfully deposited onto the surface of biochar were derived from iron powder transformed into iron-oxide. High specific surface area of 266.564 m2g-1 was achieved through Brunauer–Emmett–Teller (BET) analysis. Scanning Electron Microscopy (SEM) images demonstrate the formation of triangular pyramid-shaped nanoparticles in the adsorbent's inner and outer wall pores. Fe3O4 was coated on the surface of the adsorbent in a crystalline, carbonaceous form, as indicated by XRD peaks. A number of hydroxyl and aliphatic stretching bonds of carbon serve as functional groups in the impregnation and anionic targeted pollutants adsorption process, according to FTIR research. The establishment of the best-fit model for several anionic pollutants followed the method of multi-layer heterogeneous adsorption. Removal efficiencies of 95%, 85%, and 80% of arsenic, chromium, and fluoride are attained, respectively. Kinetic models were used to determine the adsorption process. Surface mechanism involved electrostatic attraction followed by pseudo first, second order, Bangham equation and Weber Morris intra-particle diffusion and complexation helping in adsorption of the anionic ions. Whereas, chromium and fluoride followed Temkin and Dubinin-Radushkevich adsorption isotherms. The maximum capacity of the manufactured biochar for arsenic, chromium and fluoride is estimated to be 294.1176, 204.22 and 102.36 mgg-1 respectively. Regeneration studies showed that upto 80-90% of ions can be recovered from the magnetic biochar.

How to cite: Das, S. and Mondal, S.: Separation and recovery of anions from aqueous solution through iron oxide nanoparticle impregnated biochar derived from waste wood, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-515, https://doi.org/10.5194/egusphere-egu24-515, 2024.

EGU24-631 | ECS | Orals | ERE4.6 | Highlight

Industrial Alkaline Waste Carbonation: Challenges and Opportunities. The case of Municipal Solid Waste Incineration Ashes (MSWIA) 

Quentin Wehrung, Linda Pastero, Enrico Destefanis, Caterina Caviglia, Simona Cavagna, Andrea Cotellucci, and Alessandro Pavese

The urgent need to mitigate carbon dioxide (CO2) emissions and address climate change has propelled the exploration of innovative approaches for carbon capture and storage (CCS). Among these, the carbonation of Industrial Alkaline Wastes (IAW) emerges as a promising avenue. In the design of a carbonation process, the primary challenges revolve around enhancing the CO2 absorption rate while minimizing energy consumption and water demand. This holds true irrespective of the nature of the gas stream—whether it be flue gas, pure CO2, or even air. Beyond the storage of CO2, the main co-benefit of IAW carbonation lies in the value added through waste stabilization, facilitating its reutilization.

The study seeks to contribute to the optimization of carbonation reactors by providing a comprehensive understanding of the relevant factors influencing both the CO2 absorption rate and the waste stabilization during MSWIA aqueous carbonation in open systems. The investigation considers Ca(OH)2, Mg(OH)2, and MSWIA carbonation individually, with a focus on free Ca and Mg oxides/hydroxides as the main phases providing cations for carbonation to occur. The detailed exploration of operational parameters aims to guide the design of efficient strategies, addressing the critical question of "How can an IAW carbonation reactor be optimized to achieve maximum CO2 absorption, high yields, and stable byproducts?". The investigated operational parameters include:

  • Ca(OH)2, Mg(OH)2, MSWIA initial concentrations;
  • CO2 flow rate;
  • CO2 concentration in the gas stream;
  • Temperature;
  • NaCl concentration (salinity);
  • NaSO4 concentration as accumulating impurities;
  • MSWIFA concentration as accumulating impurities;
  • Mixing system, with a comparison of bubbling (pipe), sparger and porous stone diffusor;
  • Ball-milling of MSWIFA for particle size reduction;
  • One-step vs two-step process (mineral extraction through pH-swing).

An experimental dataset, based on batch experiments, was collected using high-precision gas flow sensors to measure the percentage of flowing CO2 absorbed by the reactor under a wide range of operational conditions. Leaching tests were carried out according to the EN 12457-2 standard on solid waste. Solid-liquid phases characterisation was conducted using XRPD with Rietveld refinement, SEM-EDS and ICP-MS. A computational set comprising equilibrium and dissolution kinetic models was developed using Phreeqc to interpret CO2 absorption vs. time patterns as well as the pH dependence of the MSWIA leaching.

We acquired numerous relevant findings:

  • Ca/Mg (hydr-)oxides dissolution is widely considered as the main rate-controlling step for IAW carbonation over CO2. Using a CO2 diffusion systems, we have shown that increasing the CO2-water interfacial surface area by reducing the size of the bubbles causes a cascade of kinetic acceleration of dissolution.
  • The average NaCl seawater concentration, 3.5 wt.%, optimizes the CO2 absorption rate.
  • By employing CO2 sparger/porous stone diffusion alongside a 3.5 wt.% NaCl concentration, it becomes feasible to achieve an absorption rate exceeding 90 % for 2 L/min of CO2 when using a solution with 7.5 wt.% Ca(OH)2 in just 1 kilogram of water.

These insights pave the way for more energy-efficient and environmentally sustainable IAW reactor designs with the potential for widespread application in carbon capture and storage efforts. 

How to cite: Wehrung, Q., Pastero, L., Destefanis, E., Caviglia, C., Cavagna, S., Cotellucci, A., and Pavese, A.: Industrial Alkaline Waste Carbonation: Challenges and Opportunities. The case of Municipal Solid Waste Incineration Ashes (MSWIA), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-631, https://doi.org/10.5194/egusphere-egu24-631, 2024.

EGU24-1777 | ECS | Orals | ERE4.6 | Highlight

Utilization of steelmaking waste as a sustainable low-cost adsorbent for cationic and anionic dyes removal  

Abdullah Basaleh, Muhammad Al-Malack, Tawfik Saleh, and Bassam Tawabini

An effective magnetic polymeric composite was produced from steelmaking waste in this work. For the elimination of methyl orange MO and methylene blue MB from synthetic solutions, steel slag was treated with an acrylamide acrylic acid (SSAA) copolymer. TGA thermogravimetric analysis, SEM scanning electron microscope, XRD X-ray diffraction, BET Brunauer-Emmett-Teller surface area, and FTIR Fourier transform infrared were used to analyze the SSAA composite. The SSAA adsorption behavior for MO and MB was studied, and the impact of various factors was analyzed using one factor at a time (OFAT) and the RSM-BBD response surface method-Box Behnken Design. The second-order kinetic model accurately described the kinetic data of MO and MB, and the primary rate-limiting phase is film diffusion. The Dubinin-Raudshkevish (D-R) and Freundlich isotherms accurately characterized the MB and MO experimental outcomes, respectively. MO and MB had maximal absorption efficiencies of 97% and 94%, respectively, and capacities of 47 and 463 mg/g. The thermodynamic studies revealed that MO and MB adsorption on the SSAA was favorable and spontaneous. Physical adsorption was discovered to be the dominant mechanism for MB, whereas chemisorption was identified for MO. The regeneration investigation verified these mechanisms, in which SSAA was regenerated for MB and a negligible decline in adsorption capacity was seen after five cycles. However, for MO ions, a minor renewal of the SSAA was achieved, confirming the chemisorption mechanism. According to the thermodynamic study, the SSAA composite might be employed for the removal of cationic and anionic dyes from wastewater spontaneously and feasibly.

How to cite: Basaleh, A., Al-Malack, M., Saleh, T., and Tawabini, B.: Utilization of steelmaking waste as a sustainable low-cost adsorbent for cationic and anionic dyes removal , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1777, https://doi.org/10.5194/egusphere-egu24-1777, 2024.

Ordinary Portland Cement (OPC) is the most widely used cementitious material in cemented paste backfill at present. However, OPC production consumes massive energy and is one of the main contributors to greenhouse gas emissions. Hybrid alkali-activated cement (HAAC) is a promising alternative to Ordinary Portland Cement (OPC), mainly consisting of supplementary cementitious materials (SCMs), OPC, and alkali activators. This innovative solution not only reduces energy consumption but also mitigates carbon footprint compared to OPC production. Moreover, it is worth noting that the production process of widely used commercial alkali activators, including sodium hydroxide and sodium silicate, is associated with notable energy consumption and environmental pollution. Therefore, addressing these concerns is essential for enhancing the sustainability of HAAC and making it an environmentally friendly choice in cemented paste backfill.

Red mud (RM) is a by-product generated by the Bayer process during the production of alumina from bauxite, which is a potential alternative to commercial alkali activators due to its high alkalinity. The experimental results show that the cemented paste backfill with RM-NaOH activated slag cement exhibits higher compressive strength than that with OPC or NaOH activated slag cement as binders in different curing ages. By comparing the Life Cycle Assessment (LCA) results, the RM-NaOH activated slag cement shows reductions mainly in the environmental impact categories of terrestrial acidification potential (TAP), fossil depletion potential (FDP), ozone depletion potential (ODP), and global warming potential (GWP). The total environmental impact of RM-NaOH activated slag cement is reduced by 13.67% compared to OPC, indicating that the production of HAAC with RM as the primary activator would significantly decrease the environmental effect of OPC manufacturing.

How to cite: Feng, Y., Zhao, C., Zhang, Q., and Wang, D.: Using Bayer red mud as an alternative activator in hybrid alkali-activated cement for cemented paste backfill: Experimental investigation and life cycle assessments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3326, https://doi.org/10.5194/egusphere-egu24-3326, 2024.

EGU24-5156 | Orals | ERE4.6 | Highlight

Improving early-age performance of alkali-activated slag paste backfill with calcium salts at low temperature 

Zhuoran Wang, Xiaozhong Gu, and Haiqiang Jiang

The hydration of alkali-activated slag (AAS) is highly sensitive to the curing temperature, especially at early ages. In low temperature environment, cemented paste backfill made of AAS (AAS-CPB) exhibits notably reduced early-age uniaxial compressive strength (UCS), attributable to the inhibitory effect of low temperature on slag hydration. This study aims to improve the performance of AAS-CPB at low temperatures by incorporating chemical additives. The results shows that calcium salts, specifically CaCl2, CaSO4, and Ca(COOCH3)2, can increase the early-age UCS of AAS-CPB by up to 1050%, depending on the specific anion involved. Overall, CaCl2 provides the greatest enhancement in the UCS. However, the presence of these salts result in strength degradation at later ages. A pronounced exponential relationship is evident between UCS and ultrasonic pulse velocity. The change of conductivity and moisture content are valuable indicators of hydration process at low temperatures. C(N)-A-S-H, hydrotalcite and portlandite are the primary hydration products. Anions play a decisive role in the morphology, precipitation and quantity of C(N)-A-S-H. The slag hydration degree and UCS basically exhibit a consistent trend. 

How to cite: Wang, Z., Gu, X., and Jiang, H.: Improving early-age performance of alkali-activated slag paste backfill with calcium salts at low temperature, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5156, https://doi.org/10.5194/egusphere-egu24-5156, 2024.

EGU24-6002 | Posters on site | ERE4.6

Sustainable Solutions for Incineration Byproducts: The CLEAN Project's Innovative Approach to Municipal Solid Waste Incineration Residue Management 

Caterina Caviglia, Enrico Destefanis, Valentina Brombin, Maura Mancinelli, Annalisa Martucci, Costanza Bonadiman, and Alessandro Pavese

The fly ashes resulting from municipal solid waste incineration (MSWI FA) are classified as hazardous waste due to their high metal and soluble salt content, posing environmental risks upon reuse.
The CLEAN project, funded by the Ministry of the Environment and Protection of Land and Sea, introduced steam washing (SW) to reduce chloride and metal concentrations in FAs. This process transforms them into non-hazardous waste, suitable for stabilization, with ongoing investigations exploring the recovery of metals (Cr, Ni, Cu) aligning with the raw-secondary materials market.
Detailed elemental characterizations of solid matrices (pre- and post-SW) and liquid matrices (residual washing water, wastewater) employed X-ray fluorescence (XRF), X-ray diffraction (XRD), and inductively coupled plasma mass spectrometry (ICP-MS).
Results from a waste-to-energy plant in northern Italy indicate metals like Cr (300 mg/kg), Ni (65 mg/kg), Cu (1500 mg/kg), and Sb (1800 mg/kg) concentrating in the solid residue. After a 40% weight loss of FAs post-washing, there's an 80-90% increase in these elements per kg of ash. Residual washing water has high metal concentrations: 6000 mg/L Zn, 400 mg/L Pb, and 250 mg/L Cd, corresponding to approximately 15%, 10%, and 70% extraction from FAs (considering SW uses a 1.5-2.0 liquid-solid ratio).
Sequential extraction methods, variable pH release tests, and geochemical simulations trace metal species behavior to different speciation in FA. Many elements associate with mineralogical phases unstable at the treatment's pH (around 6), favoring mobilization (e.g., chlorides, hydroxides, carbonates, and surface adsorption).
While these chemical species pose challenges in FA, they can be valuable resources if extracted and recovered. SW yields two matrices suitable for metal recovery: a treated solid and a liquid one. For the solid matrix, increased heavy metal concentration per kg of FA favors effective extraction via targeted washing with diluted acid (e.g., HCl 2-3M), limiting reagent consumption. Analyses for the elemental characterization of wastewater are underway after absorption and recovery of metals by minerals like zeolites.

How to cite: Caviglia, C., Destefanis, E., Brombin, V., Mancinelli, M., Martucci, A., Bonadiman, C., and Pavese, A.: Sustainable Solutions for Incineration Byproducts: The CLEAN Project's Innovative Approach to Municipal Solid Waste Incineration Residue Management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6002, https://doi.org/10.5194/egusphere-egu24-6002, 2024.

As a bulk by-product of the chemical phosphoric acid industry, phosphogypsum (PG) has not been effectively utilised because of the large number of impurities, and the large amount of stockpiled on the surface of the ground poses a potential risk of environmental pollution due to the leaching of its harmful elements. Therefore, the current consideration is to combine the bulk consumption of PG with the management of the underground mining area by cementing paste backfilling technology (CPB), so as to realise the harmless disposal of PG in the management of the mining area at the same time. However, there are several scientific problems as follows:

  • PG has a large amount of phosphoric acid residue in the output process, which makes the pH of phosphogypsum around 2~3, and it is difficult to meet the alkaline environment requirements for cement hydration.
  • The poor cementing properties of PG and silicate cement lead to limited development of the strength of the PG backfilling body, and increasing the proportion of cementitious materials is bound to increase the cost of backfilling.
  • Although PG cemented backfiller can fix/stabilise most of the harmful elements leaching pollution, according to the preliminary experimental research, the fluorine leaching amount in the backfiller is still far more than the original groundwater quality grade standard (>2.0mg/L).

Therefore, on the basis of CaO neutralisation and modification of PG, we choose diversified active solid wastes such as steel slag and slag as backfilling cementitious materials, and use PAC or biochar as targeted fluorine fixation materials. Afterwards, we can obtain the parameters of PG backfilling ratios in line with the requirements of strength and environmental protection through a large number of experiments. The hydration and fluorine leaching mechanisms were explained by XRD, EPMA-WDS, heat of hydration test, compressive strength test and fluorine leaching test.

How to cite: Wang, D., Zhang, Q., and Tao, Y.: Research on the transformation and immobilization mechanism of fluorine-containing phase in phosphogypsum low-carbon gel backfilling system, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6954, https://doi.org/10.5194/egusphere-egu24-6954, 2024.

EGU24-7365 | ECS | Posters on site | ERE4.6

Spectroscopic study on heavy metals stabilization by repetitive in situ iron oxide synthesis 

Hosub Lee, Seulki Jung, Jinsung An, and Kyoungphile Nam

In a spatially limited contaminated site, in situ synthesis of iron oxide would be an option for metal stabilization. We proposed the repetition of in situ iron oxide synthesis through additional simultaneous injection of iron oxide synthesizing solution, Fe(NO3)3, and NaOH to enhance the stability of heavy metals. In this study, iron oxide was repeatedly synthesized, and the behavior of immobilization of Cd, Zn, and As was investigated. Cd, Zn, and As were surface-adsorbed on the first synthesized iron oxide 69±0.97%, 38±1.6%, and 23±0.96%, respectively. The remaining metals were adsorbed into the ferrihydrite structure (i.e., incorporation). Repeating the synthesis resulted in reduced surface adsorption rates of Cd and Zn at 54±2.6% and 23±1.5%, respectively, while As adsorption remained constant at 23±0.54%. Meanwhile, the crystallinity of the second and third-synthesized iron oxides measured using X-ray diffraction (XRD) was similar to that of pure ferrihydrite. Encapsulation of the surface adsorbed metals occurred due to particle growth on pre-synthesized iron oxide by agglomeration on the surface. However, encapsulation of surface-adsorbed As was not observed, probably due to its inhibitory effect on ferrihydrite agglomeration. The incorporation and encapsulation of heavy metals were determined by scanning transmission electron microscopy (STEM). The zone axis [11¯0] fast Fourier transform (FFT) reveals that the interplaner lattice space (d-spacing) of the c-axis elongates by 0.001 – 0.012 nm compared to pure ferrihydrite. In addition, a common zone of axis of brighter spots was also found at multiple bulk sites of iron oxide of high-angle annular dark-field (HAADF) image, indicating metal incorporation within the iron oxide. The abundance of metals as an atomic ratio measured by TEM energy-dispersive X-ray spectroscopy (EDS) line-scanning from the edge to the bulk site of iron oxide showed encapsulation of metals by repetition. The metal abundance at the edge site decreases with additional synthesis due to an increase in the number of Fe in the surrounding area, while a constant abundance of stabilized metal from a single synthesis was consistently detected across the edge to the bulk site. However, As shows a constant abundance in both single and repetitive synthesis. The Fourier transform of Fe K-edge extended X-ray absorption fine structure spectroscopy (EXAFS) was also able to determine the incorporation of heavy metals within the iron oxide by the single synthesis. As expected, the number of neighboring second and third shell-ions increased and those radial distances were shortened by 0.01 – 0.03 Å are distinctively observed for Zn and As. Electron probe micro-analyzer (EMPA) analysis results indicate a lower relative metal concentration within the third-synthesized iron oxide structure than the first synthesis. This result exhibits repetitive synthesis induces agglomeration and aggregation of previously synthesized iron oxide further encapsulates surface-adsorbed metals which explains the reduction of surface-bound metals extractability with an increasing number of the iron oxide synthesis. The findings suggest that repeated synthesis of iron oxide can enhance the stabilization of heavy metals by encapsulating Cd and Zn, which were previously adsorbed on the iron oxide surface synthesized by a single application.

How to cite: Lee, H., Jung, S., An, J., and Nam, K.: Spectroscopic study on heavy metals stabilization by repetitive in situ iron oxide synthesis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7365, https://doi.org/10.5194/egusphere-egu24-7365, 2024.

EGU24-13218 | ECS | Orals | ERE4.6

Ramses-4-CE: Towards Enhanced Generalization of RGB/Hyperspectral Imaging Data Processing 

Elias Arbash, Margret Fuchs, Behnood Rasti, Sandra Lorenz, Pedram Ghamisi, and Richard Gloaguen

In the quest for achieving the principles of a circular economy, our Helios Lab seeks to optimize the e-waste recycling industry with its innovative Ramses-4-CE project (KIC RM 19262). Ramses focuses on the development of a smart network comprising multimodal optical non-invasive sensors mimicking industrial scenarios with a conveyor belt that can attain speeds of several meters per second. The primary objective is to facilitate the comprehensive identification and characterization of e-waste materials, particularly printed circuit boards (PCBs), plastics, and rare earth elements (REE).

The sensor ensemble encompasses a laser profiler generating height maps, an RGB camera capturing surface spatial features, hyperspectral cameras capturing the spectral features, and chemical characteristics obtained with a Raman spectroscopy sensor affixed to a robotic arm. Each sensor type offers unique advantages and inherent challenges. RGB cameras with their data facilitate fast, highly accurate, and smart data processing e.g., using machine learning (ML) and deep learning (DL) object detection and segmentation techniques in shredded plastics, while hyperspectral imaging (HSI) aids in polymer identification based on spectral fingerprint libraries. Nonetheless, HSI poses challenges such as large data size due to its abundant information, noise interference, and overlong processing times.

To optimize the data processing pipeline, meticulous preprocessing and processing methods have been devised. Upon data acquisition of different objects and materials, data co-registration is executed on the resulting RGB images and hyperspectral cubes, followed by object detection and segmentation of valuable objects on both data types. For objects eluding identification via RGB and hyperspectral imagery, a Raman spectroscopy-based validation is involved for detailed chemical analysis.

Yet, exerting high accuracy in HSI pixel-wise classification on multi-unseen data cubes necessitates HSI classification models with robust generalization capabilities. Towards this aim, smart automated masking of undesired objects in the hyperspectral scene is developed. HS cube contains abundant data causing their large volume size. This abundance highlights the useful information, while concurrently amplifying noises and artifacts, detrimentally affecting both data processing speed and model generalization. Masking undesired objects in the HSI reduces the number of pixel vectors skewing calculations in preprocessing steps and DL models training routines, leading to enhanced segmentation models, i.e., masking unwanted data vectors from HSI allows exclusive processing for desired targets elevating processing speed without compromising accuracy. 

How to cite: Arbash, E., Fuchs, M., Rasti, B., Lorenz, S., Ghamisi, P., and Gloaguen, R.: Ramses-4-CE: Towards Enhanced Generalization of RGB/Hyperspectral Imaging Data Processing, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13218, https://doi.org/10.5194/egusphere-egu24-13218, 2024.

EGU24-15399 | ECS | Orals | ERE4.6

Implementing a new model of urban solid waste management at a local scale: application to the municipality of l'alcora (castellón, spain) 

Estela Pérez, Javier Rodrigo-Ilarri, and Maria-Elena Rodrigo-Clavero

The implementation of efficient municipal waste management systems is crucial to address current environmental challenges. These systems allow for the minimization of waste generation, promotion of reuse and recycling, and proper management of remaining waste. By reducing the amount of waste sent to landfills, soil, water, and air pollution decreases, and the emission of greenhouse gases is limited. Moreover, efficient municipal waste management fosters the circular economy by recovering valuable resources from waste, thereby contributing to the conservation of raw materials and long-term sustainability.

This work presents a methodology for urban waste management tailored to medium-sized municipalities (approximately 10,000 inhabitants). It highlights the resources and tools available at the municipal level to achieve the objectives set by European Directives on waste management. These resources encompass environmental communication and information, economic, fiscal, and regulatory instruments, as well as a proposal for a model of urban solid waste collection.

The proposed methodology is applied to the municipality of l'Alcora (Castellón, Spain), whose current management model relies on anonymous municipal waste collection, where citizens voluntarily decide where to dispose of their waste based on their environmental awareness, without any form of reward or penalty for their actions. This voluntariness and limited promotion of environmental awareness have led to a general lack of interest among the population in waste management. This situation has, in general, caused Spain to lag behind other EU member states in achieving the goals of waste prevention, valorization, and recycling set by the European Union.

How to cite: Pérez, E., Rodrigo-Ilarri, J., and Rodrigo-Clavero, M.-E.: Implementing a new model of urban solid waste management at a local scale: application to the municipality of l'alcora (castellón, spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15399, https://doi.org/10.5194/egusphere-egu24-15399, 2024.

EGU24-15407 | Orals | ERE4.6

When environmentally friendly solutions are worse than the contaminated product: the KEU case study 

Orlando Vaselli, Federica Meloni, Barbara Nisi, Marcello Panarese, Jacopo Cabassi, Giordano Montegrossi, and Ivan Fagiolino

KEU (Kraftanlagen Energie und Umwelttechnick) is a by-product of a pyrolyzed waste of sewage sludge produced by wastewater treatment from tannery industries. KEU is regarded as an industrial non-hazardous waste after inertization to obtain a sintering granulate and usually mixed with demolition-construction or industrial mud products to produce EoW (End of Waste) material. However, the resulting materials are apparently responsible of the anomalous concentrations of Cr and CrVI and other PTEs (Potentially Toxic Elements), recovered in several domestic wells distributed along the Siena-Empoli motorway (Tuscany, central Italy) since KEU was used as roadbed. Similar concerns were also evidenced in other areas, as in the local groundwater system, where the KEU industrial by-product is stored, anomalous contents of heavy metals were determined.

In this work, an extensive analytical work was conducted to characterize the mineralogical and chemical bulk composition of eight KEU-bearing samples collected from different cumulus stored in an aggregate crushing plant and one pyrolysis char (the KEU) sample. It is remarkable the presence of high Rare Earth Elements (REEs) concentrations. While pure KEU has total REEs of 14 mg/kg, the KEU-bearing materials are up 4300 mg/kg.

To verify whether the KEU-bearing samples were able to release PTEs, three leaching tests (after 1-hour, 1-day and 7-days) were performed by shaking 20 g in 200 mL of MilliQ and 20 g in 200 mL of CO2-saturated MilliQ water, the latter simulating the interaction between meteoric waters and KEU-bearing materials. The resulting suspensions of all the aliquots were centrifuged and the surnatant was analyzed for pH, electrical conductivity, main composition, CrVI and trace elements. The 1-day post-centrifugation residue was leached and shaken for 7 days to evidence whether the PTEs were still released after a relatively long-term leaching. The analytical results showed that the MilliQ water leachates have high pH values (up to 11.75) whereas those obtained by CO2-saturated MilliQ partly buffer the pH although moderately alkaline pH values were measured. Our study indicates that, as expected, in most cases the CO2-saturated MilliQ water is able to more efficiently scavenge PTEs than those solubilized by MilliQ water. Moreover, the 1-day leachates resulted to be enriched in many PTEs with concentrations, in most cases, from hundreds to thousands microg/L. Despite a general decrease, in the 7-days leachates, high contents of some heavy metals were still measured, suggesting that prolonged interaction between meteoric waters and the KEU-bearing materials is able to transfer PTEs to the groundwater systems. The 1-hour and 1-day leachates showed relatively high concentrations of CrVI (from 20 to 1370 microg/L) while REEs were always approaching the detection limit or below it. Another important aspect is that the investigated samples are chemically heterogeneous, indicating that the inertization process was not performed by using the same amount of demolition and construction materials although the main composition was mostly Ca-SO4. Notwithstanding such an inertization, aimed at stabilizing unwanted toxic elements, its efficiency is rather scarce and, consequently, its use as by-product is strongly discouraged unless a more adequate inertization process is applied.

How to cite: Vaselli, O., Meloni, F., Nisi, B., Panarese, M., Cabassi, J., Montegrossi, G., and Fagiolino, I.: When environmentally friendly solutions are worse than the contaminated product: the KEU case study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15407, https://doi.org/10.5194/egusphere-egu24-15407, 2024.

EGU24-16746 | Posters on site | ERE4.6 | Highlight

Comprehensive Analysis and Machine Learning Modeling of Hydrochar Characteristics: Optimizing Production Variables and Predictive Insights 

Rubén Forján, Álvaro Amado-Fierro, Teresa A. Centeno, Carlos A. López-Sánchez, Jose Luis R. Gallego, and Lorena Salgado

Hydrothermal carbonization (HTC) at temperatures of 150-250°C and self-generated pressures of 1−5 MPa is an efficient technology to convert wet biomass wastes into stable carbon-rich solids (hydrochars) with great potential for energy production/storage, soil amendment, sustainable construction, adsorption, catalysis, etc., within a circular economy framework.

The different composition of the biomass residues, the impact of the operating conditions and the diversity of the reactions that take place during the HTC process make the design of hydrochar production very challenging.

In this study, machine learning (ML) techniques enabled addressing the inherent complexity of interactions among diverse variables and accurately modeling their relationships in order to guide the hidrochar production and properties. Three algorithms, namely Multiple Linear Regression (MLR), Support Vector Machine (SVM), and Random Forest (RF), have been chosen and systematically compared in their ability to predict the variables that exert the most influence on the development of a stable hydrochar.

Analyses were accomplished on 93 representative samples of hydrochars derived from 12 radically different bio-wastes (out-of-use woods, apple bagasse, organic fraction from municipal solid waste, sewage sludge, digestate, etc.) subjected to HTC at 180, 200 and 230 °C for 2 and 4 h.

The modeling of four key performance indicators associated with production and quality of hydrochar, such as H/C and O/C atomic ratios, the calorific value (expressed as higher heating value, HHV) and yield have been developed. The approach relies on the comprehensive analysis of a number of dependent variables categorized into six main groups: set-up parameters, operational parameters, hydrochar characterization (proximate and ultimate analysis) and thermal properties under inert (N2), oxidative (air) and reactive (CO2) atmospheres. Each category addresses specific aspects of the HTC process and/or hydrochar formation and its properties.

The results show that SVM achieves a better goodness of fit for H/C (R2=0.88), while RF for O/C (R2=0.92), HHV (R2=0.96), and yield (R2 = 0.88) variables, both of them no-parametric algorithms. Regarding the dependent variables, the most influential categories in predicting H/C are those associated with hydrochar characterization and combustion thermogram parameters, being the variable with the greatest importance, the fixed carbon, associated to the solid carbon that remains in char after devolatilization. For O/C, those related to hydrochar characteristics and pyrolysis thermogram parameters have a relevant role. The HHV is determined by parameters of hydrochar characterization and gasification thermograms, being the most important variables the fixed carbon, associated to the solid carbon that remains in char after devolatilization, and the reactivity when 1000 °C reached and 30 and 60 minutes passed. The results obtained for yield indicate that the most important category is operational parameters, being the variables with the greatest significance, the energy, indicative of energetical harvesting potential, and densification ratio, indicative of energetical improvement.

This investigation belongs to the European Union's Horizon 2020 research and innovation program, under grant agreement No. 101006656 (GICO Project), and also to the Agroalimentación Cero Emisiones project funded by Misiones Científicas del Principado de Asturias 2022 AYUD/2022/24227 (Spain).

How to cite: Forján, R., Amado-Fierro, Á., Centeno, T. A., López-Sánchez, C. A., R. Gallego, J. L., and Salgado, L.: Comprehensive Analysis and Machine Learning Modeling of Hydrochar Characteristics: Optimizing Production Variables and Predictive Insights, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16746, https://doi.org/10.5194/egusphere-egu24-16746, 2024.

EGU24-18228 | ECS | Posters on site | ERE4.6 | Highlight

Impacts of climate-driven wetting and drying on mobilization of trace metals in legacy coastal wastes in the United Kingdom 

Alessia Nannoni, Patrick Byrne, Patrizia Onnis, Alex L Riley, Catherine Gandy, Ian Burke, Karen Hudson-Edwards, Will Mayes, and Adam Jarvis

Climate change is expected to significantly affect the release of toxic elements from legacy waste landfills across coastal areas because it will enhance severe flooding, erosion, and extreme wetting-drying cycles. The UK’s industrial past resulted in a wide range of legacy wastes deposited in estuarine and coastal settings, for a total of 2550 sites. In this perspective, a NERC project is ongoing to provide a national-scale assessment of geochemistry and mobility of these wastes, which is necessary to establish environmental and ecological risks and to prioritize sites for management interventions. In the project framework, a mesocosm experiment was carried out to investigate the leaching processes that can occur in different types of legacy wastes (LW) disposed across the UK coasts. The experiment was designed to study how wetting and drying cycles affects the release of pollutants in the coastal areas. Four sites were selected, each one for a different type of LW: colliery (L), landfill municipal wastes (CB), metal smelter (CP), and mining-impacted sediments (HE). These four sites represent the range of LW geochemistry encountered across the UK. Each wetting/drying cycle (WDC) lasted 2 weeks. Artificial rainwater was used to inundate the columns. Water samples were collected weekly for Dissolved Organic Carbon (DOC), major ions and metals. EC, Eh, DO, and DOC showed a great variability both at inter- and intra-sites: the L samples were the most acid ones (pH = 3.3 – 5.1), whereas the other sites showed pH values ranging from 6.0 to 8.7. HE samples showed the largest variation ranges for EC and DOC (409 – 109000 µS/cm and 8.3 – 405.8 mg/l, respectively), whereas the CP ones showed the narrowest ranges for both parameters (176 – 592 µS/cm and 0.2 – 248.1 mg/l, respectively). The maximum variation for EC and pH occurred after the first WDC for all the sites but CP, which showed a progressive decrease in both parameters throughout the experiment. DO, Eh, and DOC varied more irregularly for all sites. For each site, Control samples showed wider ranges of variation than those that experienced the WDC but the trends were similar for both control and non-control ones. These preliminary data, together with trace metal data, suggest that leaching processes are more likely to be efficient at the end of prolonged dry periods when heavy storms occur. Extreme climate conditions are expected to become more frequent in the near future, therefore a proper management is mandatory to reduce the risk posed by the coastal legacy wastes.

How to cite: Nannoni, A., Byrne, P., Onnis, P., Riley, A. L., Gandy, C., Burke, I., Hudson-Edwards, K., Mayes, W., and Jarvis, A.: Impacts of climate-driven wetting and drying on mobilization of trace metals in legacy coastal wastes in the United Kingdom, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18228, https://doi.org/10.5194/egusphere-egu24-18228, 2024.

EGU24-19079 | Orals | ERE4.6

Modeling Anaerobic Digestion Processes to Treat the Organic Fraction of Municipal SolidWaste in a Megacity: A Comprehensive Approach to Sustainable Waste Management 

Ana Paola Becerra Quiroz, Johanna Karina Solano Meza, María Elena Rodrigo-Clavero, and Javier Rodrigo-Ilarri

The organic fraction of municipal solid waste (OFMSW) represents between 40% and 50% of the solid waste of a megacity and despite its great potential for use, continues to generate environmental problems, which highlights the need to continue the search for sustainable and efficient solutions [1].  Current research processes have been geared towards anaerobic digestion (AD) as a promising technology to treat this waste. To this end, this study focuses on examining variables and mathematical models to precisely implement AD processes in a megacity, while exploring its technical and economic feasibility to address the increased amounts of these wastes, in order to optimize current technological developments.  

In megacities such as Bogotá, the case study area for this research paper, addressing the environmental, social and public health impacts generated by OFMSW is of the utmost importance. Anaerobic digestion is projected as an innovative and sustainable alternative, which not only contributes to treating waste, but also as a source of renewable energy, in addition to generating valuable by-products for agriculture. However, successfully applying AD in a megacity requires an in-depth analysis of the processes involved and the examination of multiple variables for its integration into models that become essential decision-making tools.

The following are among the technical variables of analysis for these processes and their subsequent modeling: OFMSW composition, temperature, carbon-to-nitrogen ratio, pH, volatile fatty acids and the presence of inhibitors as critical factors that impact AD performance. Given this scenario, having an adaptive approach that ensures predictive and consistent results over time is indispensable. In addition to these variables, aspects associated with economic, environmental, and social viability should be included, such as population size and projections, climate variability and seasonality, costs associated with the comprehensive service, correct separation at the source, policies and governance models, and land use plans established within the development plans of the cities[2]. Thus, the results obtained from this research study will provide a comprehensive understanding of the factors, processes and variables that influence the efficiency of AD of OFMSW in a megacity. These findings will not only contribute to the design of more efficient systems, but also support decision-making processes, as well as the formulation of waste management strategies, policies and practices at the city level.

[1]      L. M. Ulloa-Murillo, L. M. Villegas, A. R. Rodríguez-Ortiz, M. Duque-Acevedo, and F. J. Cortés-García, "Management of the Organic Fraction of Municipal Solid Waste in the Context of a Sustainable and Circular Model: Analysis of Trends in Latin America and the Caribbean," Int J Environ Res Public Health, vol. 19, no. 10, 2022, doi: 10.3390/ijerph19106041.

[2]       L. Mu, L. Zhang, K. Zhu, J. Ma, and A. Li, "Semi-continuous anaerobic digestion of extruded OFMSW: Process performance and energetics evaluation," Bioresour Technol, vol. 247, pp. 103-115, 2018, doi: 10.1016/j.biortech.2017.09.085.

How to cite: Becerra Quiroz, A. P., Solano Meza, J. K., Rodrigo-Clavero, M. E., and Rodrigo-Ilarri, J.: Modeling Anaerobic Digestion Processes to Treat the Organic Fraction of Municipal SolidWaste in a Megacity: A Comprehensive Approach to Sustainable Waste Management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19079, https://doi.org/10.5194/egusphere-egu24-19079, 2024.

EGU24-21199 | Posters on site | ERE4.6

Use of sustainable extractants for the Zn recovery from spentbatteries for agricultural purposes 

Silvia Patricia Barragan Mantilla, Raquel Ortiz, Gabriel Gascó, Laura Sánchez, Patricia Almendros, and Ana Méndez

The demand for metals is increasing, so the need of looking for greener alternatives to obtain them [1]. Techniques such as hydrometallurgy have been thoroughly studied to obtain better metal recoveries from different feedstocks, including low-grade ores, mine tailings, and spent batteries, which are normally difficult and expensive to treat [2]. This study focused on the implementation of an amino acid to promote metal recovery, particularly Zn from spent batteries, and its possible application in agriculture. For the leaching, we used a ratio of glycine (8/1), hydrogen peroxide, and sodium hydroxide (to adjust pH) at room temperature, 200 rpm, and different pH values (7.0, 8.0, 9.0, 10.0, 11.0, and 12.0). At 0.5, 1, 2, 4, 6, 22, and 24 h, we measured pH and potential and took aliquots of each sample. Subsequently, samples were characterized by atomic absorption spectrometry and processed. According to the results, the best recoveries were achieved at lower pH values. Although the results obtained are not on par with those of acid leaching systems, they provide important insights into factors that may affect recovery rates (i.e., type of material, pH, glycine/oxidant agent) [3,4], which leads to the development of strategies to optimize them.

Acknowledgments: This research has been funded by the Ministerio de Ciencia e Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI), and European Union “NextGenerationEU” with grant number TED2021-131198B-I00 “GREEN-AGRO-REC”.

[1] Henckens, M. L. C. M., Driessen, P. P. J., & Worrell, E. (2014). Metal scarcity and sustainability, analyzing the necessity to reduce the extraction of scarce metals. Resources, Conservation and Recycling, 93, 1–8. https://doi.org/10.1016/j.resconrec.2014.09.012

[2] Mohanraj, G. T., Rahman, M. R., Arya, S. B., Barman, R., Krishnendu, P., & Singh Meena, S. (2022). Characterization study and recovery of copper from low-grade copper ore through hydrometallurgical route. Advanced Powder Technology, 33(1). https://doi.org/10.1016/j.apt.2021.12.001

[3] Shin, D., Ahn, J., & Lee, J. (2019). Kinetic study of copper leaching from chalcopyrite concentrate in alkaline glycine solution. Hydrometallurgy, 183, 71–78. https://doi.org/10.1016/j.hydromet.2018.10.021

[4] Tanda, B. C., Eksteen, J. J., & Oraby, E. A. (2017). An investigation into the leaching behavior of copper oxide minerals in aqueous alkaline glycine solutions. Hydrometallurgy, 167, 153–162. https://doi.org/10.1016/j.hydromet.2016.11.011

How to cite: Barragan Mantilla, S. P., Ortiz, R., Gascó, G., Sánchez, L., Almendros, P., and Méndez, A.: Use of sustainable extractants for the Zn recovery from spentbatteries for agricultural purposes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21199, https://doi.org/10.5194/egusphere-egu24-21199, 2024.

EGU24-21201 | Posters on site | ERE4.6 | Highlight

Zinc leaching potential of environmentally friendly zinc sources obtained from spent batteries 

Raquel Ortiz Castillo, Silvia Patricia Barragán Mantill, Gabriel Gascó, Ana Méndez, Laura Sánchez, and Patricia Almendros

The use of highly effective sources of zinc in agriculture is necessary to achieve adequate crop quality and to avoid potential environmental hazards [1]. The use of synthetic chelating agents can lead to environmental risks such as contamination by leaching into aquifers [2]. There is currently a growing interest in the use of environmentally friendly zinc sources as an alternative to traditional ones [3]. This study focused on the evaluation of the leaching capacity of different Zn sources extracted from spent batteries with H2SO4 2M, H2SO4 0.25M or environmentally friendly complexes (glycine or citrate) in comparison with the traditional ZnSO4 source. Columns of 15 cm height and 1.5 cm diameter with 25 grams of washed sand were used for this. The treatment to carry 5 mg of Zn was added to each column and covered with another 5 g of sand. A flow of 10 ml/h of 0.01 M CaCl2 solution was added from the top of the columns. The leachates were collected in 20 ml portions until a total of 400 ml. The result showed distinct trends for the added treatments. The evolution of accumulated leached Zn for each of the treatments was fitted to the logistic model. The Zn-H2SO4 0.25M treatment achieved the highest percentages of total leached Zn at 400mL, accounting for more than 98% of the leached Zn with respect to the total Zn added to the columns. This percentage was statistically higher (P˂0.05) than the rest of the treatments, among which there were no significant differences in the total leached Zn, which reached percentages of between 72.68 and 77.12% (Zn-citrate and ZnSO4, respectively).

Acknowledgments: This research has been funded by the Ministerio de Ciencia e Innovación y Universidades (MCIU), Agencia  Estatal de Investigación (AEI), and European  Union  “NextGenerationEU”  with grant number  TED2021-131198B-I00 “GREEN-AGRO-REC”.

1.  Alloway, B.J. Zinc in Soils and Crop Nutrition; Second edi.; International Zinc Association Brussels, Belgium: Brussels, Belgium and Paris, France, 2008;
2. Chandrika, K.S.V.P.; Patra, D.; Yadav, P.; Qureshi, A.A.; Gopalan, B. Metal Citrate Nanoparticles: A Robust Water-Soluble Plant Micronutrient Source. RSC Adv. 2021, 11, 20370–20379, doi:10.1039/d1ra02907j.
3. Ortiz, R.; Gascó, G.; Méndez, A.; Sanchez-Martín, L.; Obrador, A.; Almendros, P. Comparative Study of Traditional and
Environmentally Friendly Zinc Sources Applied in Alkaline Fluvisol Soil: Lettuce Biofortification and Soil Zinc Status. Agronomy 2023, 13, 4–15, doi:10.3390/agronomy13123014.

How to cite: Ortiz Castillo, R., Barragán Mantill, S. P., Gascó, G., Méndez, A., Sánchez, L., and Almendros, P.: Zinc leaching potential of environmentally friendly zinc sources obtained from spent batteries, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21201, https://doi.org/10.5194/egusphere-egu24-21201, 2024.

Reducing the substantial carbon dioxide emissions from mining activities is essential for establishing environmentally friendly mines and achieving carbon neutrality in the mining industry. This study introduces a practical approach for reducing carbon dioxide emissions in underground mining by leveraging shotcrete, a widely used material in mining, as a carrier for carbon mineral sequestration. Additionally, to further mitigate the overall carbon footprint related to the shotcrete preparation, we enhanced the carbonation process by utilizing bacteria and incorporating solid waste materials as ordinary Portland cement substitutes (mainly yellow phosphorus slag and coal gasification slag). Our research reveals that shotcrete containing bacteria microorganisms exhibits significantly enhanced carbonation rates compared to conventional shotcrete. Specifically, it absorbs approximately 0.76 kgCO2 per square meter within a span of 14 days. Moreover, the substitution of solid waste materials fixed with bacteria not only enhances the mechanical performance of the shotcrete but also further augments the bacterial carbonation ability. Characterization techniques, such as XRD and SEM/EDS, reveal the presence of captured carbon dioxide in the form of calcite, pyrrhotite, and magnesite, resulting in a denser cementitious matrix and improved mechanical properties.

How to cite: Yuan, X., Zhang, C., and Song, Z.: Mechanical properties and carbon sequestration potential of MICP-based shotcrete partially substituted with industrial solid waste, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22556, https://doi.org/10.5194/egusphere-egu24-22556, 2024.

EGU24-369 | ECS | Posters on site | ERE4.8 | Highlight

Potential lithium enrichment in pyrites from organic-rich shales 

Shailee Bhattacharya, Michael C. Dix, Shikha Sharma, Albert S. Wylie, and Tom Wagner

In order to meet the technological needs of the energy transition, batteries of all scales, particularly those that power electrical vehicles, have become increasingly important. Lithium-ion batteries are in wide use at present, and continued research to improve them has been a focus of energy engineering. This, in turn, has greatly increased the demand for lithium (Li) as a natural resource. While the primary ores of Li (pegmatite, salar brine, and volcanic-associated clay) are generally well-understood, it would be desirable to identify additional Li sources that could be safely and economically exploited. Using material from previous industrial operations (e.g., mine tailings or drill cuttings) as a source of additional Li would be attractive as it would generate little or no new waste material.

Our study was carried out on 15 Devonian shale samples of varying organic richness from wells drilled in the Appalachian basin (USA). Sequential extraction of the samples was performed to measure Li recovery from targeted rock-forming phases, namely the carbonates, Fe-Mn oxyhydroxides, pyrites, and organic matter. The mineralogy of the post-leaching residue was found to be dominated by silicates and anatase, suggesting the target phases were successfully leached out of the whole rock.

Unsurprisingly, the data shows higher whole-rock Li values are observed in samples with a higher total clay content. The lowest whole-rock Li contents correspond to samples having higher contents of total organic carbon (TOC) and pyrite. Unexpectedly, however, samples with relatively lower Li contents (22 ppm) can liberate up to 54% of the total lithium from pyrite alone. Furthermore, we observe a positive correlation between pyrite content and %Li recovery in the pyrite leachate (r2= 0.732). These initial findings suggest that pyrite in conjunction with organic matter may play a previously unrecognized role in the Li distribution in organic-rich shales. The geochemical processes that might cause Li enrichments associated with pyrite are not well-understood. However, since Li mobility is highly sensitive to small increases in temperature, the very high thermal maturation of the studied shale sequence may have significantly impacted Li remobilization during the smectite-to-illite clay-mineral transformation. The common Li-mineral that can coexist with different phases of FeS is Li2S at temperatures ⩽ 75°C – 135°C. Several reaction mechanisms have been proposed, but there is little known about the rate kinetics and reaction steps involved in Li association with pyrite in shales.

This study suggests the possibility that some Li may be sequestered in pyrite in organic-rich shales. As pyrite is a common mineral in the Appalachian Basin, this has implications for exploiting shale pyrite in the Devonian sequence if the Li proves economically extractable. Drill cuttings from past and current oil and gas operations are a ready material upon which to test the feasibility of this concept.

How to cite: Bhattacharya, S., Dix, M. C., Sharma, S., Wylie, A. S., and Wagner, T.: Potential lithium enrichment in pyrites from organic-rich shales, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-369, https://doi.org/10.5194/egusphere-egu24-369, 2024.

EGU24-3754 | Posters on site | ERE4.8

Evaluating the potential source of contamination from sulfide minerals in major rocks in South Korea 

Gil-Jae Yim, Seung-Jun Youm, Hyeop-Jo Han, Seon-Yong Lee, and Jin-Young Lee

The utilization of surrounding rocks is required in human living areas, and these development activities create large cut slopes and generate large amounts of cut rocks as construction materials. If these development areas are strata containing sulfide minerals (pyrite, etc.), contamination may occur, causing environmental pollution problems in the development site and surrounding areas. Several methods have been studied for the preliminary identification of potentially contaminated rocks, including Acid Base Accounting (ABA), Modified ABA procedures, Carbonate Neutralization Potential determinations, Humidity cell tests, Column tests, Batch reactor (Shake flask) tests, and Field tests (Orava, 1997; USEPA and Hardrock Mining, 2003). Studies on rock samples have resulted in most of the samples being classified as Non-Acid Forming (NAF), with some samples containing sulfide minerals (such as pyrite) being classified as Potentially Acid Forming (PAF). It can be expected that future development of these rocky areas may affect the surrounding environment or rock utilization. Therefore, these rock areas are considered to be in need of management. It would be desirable to investigate the occurrence of pollution sources caused by mineral sulfides in advance and take appropriate countermeasures. It is expected to reduce the economic losses that may occur in the future, and it is judged that the pollution problem of the surrounding environment can be further reduced.

How to cite: Yim, G.-J., Youm, S.-J., Han, H.-J., Lee, S.-Y., and Lee, J.-Y.: Evaluating the potential source of contamination from sulfide minerals in major rocks in South Korea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3754, https://doi.org/10.5194/egusphere-egu24-3754, 2024.

The assessment in accordance with the Water Framework Directive and the EU Water Framework Directive continues to show poor chemical status for around one third of groundwater bodies in Germany due to excessive nitrate concentrations. In many regions, this is due to high nitrogen fertiliser intensities that have been applied to agricultural land for decades.

Nitrate input and degradation processes in aquifers are modelled using step-by-step hydrogeochemical continuous stirred tank reactors (CSTR) sequences with PHREEQC. This makes it possible to show how the overall water quality is characterised by the interaction of hydrogeochemical sub-processes such as nitrogen and lime fertilisation, substance releases from grassland ploughing, denitrification via organic carbon (heterotrophic degradation) and most importantly pyrite (lithotrophic degradation) and sulphate reduction, but also nitrate breakthroughs and well clogging.

CSTR models are not discretised spatially or temporally; their focus is on identifying and quantifying the relevant hydrogeochemical reactions. The advantage of this method is much shorter and more manageable calculation times than with fully coupled reactive transport models. They provide the user with a comprehensive hydrogeochemical understanding of nitrate degradation by pyrite oxidation processes in groundwater. In addition to reaction kinetic aspects, this also includes the effects of a loss of nitrate degradation capacity [1]. In the focus is the dissolution of pyrite and its re-precipitation and a reaction front developing into the system [2]. Moreover, concentrations of pyrite dissolution products (iron, sulphate, trace metals) can be understood.

Hydrogeochemical modelling in this sense is initially retrospectively oriented based on measurements and the longest possible time series. However, a hydrogeochemical CSTR sequence has been checked for plausibility and validated with sensitivity and parameter studies can then also be used to forecast water quality [3]. This provides a "tool" with which the effects of anthropogenic interventions in a geosystem can be calculated with regard to the effects on groundwater and raw water quality.

 

[1] Wilde, S., Hansen, C. & Bergmann, A. Nachlassender Nitratabbau im Grundwasser und deren Folgen – abgestufte modellgestützte Bewertungsansätze. Grundwasser 22, 293–308 (2017). https://doi.org/10.1007/s00767-017-0373-0

[2] Kübeck, C., Hansen, C., König, C. et al. Ableitung der Reaktivität von organisch gebundenem Kohlenstoff in redoxzonierten Grundwasserleitern – Hydrogeochemische Modellierung kinetisch angetriebener Reaktionssysteme. Grundwasser 15, 103–112 (2010). https://doi.org/10.1007/s00767-009-0136-7

[3] Jesußek, A., Hansen, C. & Wilde, S. Identifikation und Regionalisierung von Nitratabbauprozessen in einem Grundwasserleiter – Möglichkeiten und Nutzen für die Wassergewinnung. Grundwasser 21, 333–344 (2016). https://doi.org/10.1007/s00767-016-0337-9

How to cite: Hansen, C. and Kühn, M.: Pyrite and its role in the development of nitrate pollution and raw water quality in water catchment areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5822, https://doi.org/10.5194/egusphere-egu24-5822, 2024.

EGU24-6083 | ECS | Posters on site | ERE4.8

Pyrite-based trace element fingerprints for methane and oil seepage 

Daniel Smrzka, Zhiyong Lin, Patrick Monien, Wolfgang Bach, Jörn Peckmann, and Gerhard Bohrmann

Pyrite forms at marine hydrocarbon seeps as the result of the microbial oxidation of methane, organic matter, and crude oil coupled to sulphate reduction. Redox sensitive and nutrient trace elements in pyrite may hold valuable information on present and past seepage events, the evolution of fluid composition, as well as the presence of heavy hydrocarbon compounds from crude oil. This study uses the trace element compositions of pyrite that formed at methane seeps and crude oil-dominated seeps to constrain element mobilities during the sulphate reduction processes, and to which degree specific trace elements are captured by pyrite. Pyrite forming at oil seeps shows high Mn/Fe ratios and high Mo content compared to pyrite from methane seeps. These patterns suggest either more intense or persistent sulphidic conditions, or an intensified manganese (oxy)hydroxide shuttle process at oil seeps. Copper and Zn are enriched in oil seepage-derived pyrite while Ni and V enrichment is less pronounced, suggesting either a selective uptake of specific elements by pyrite, or varying trace element compositions of organic compounds oxidized via microbial reduction.   

How to cite: Smrzka, D., Lin, Z., Monien, P., Bach, W., Peckmann, J., and Bohrmann, G.: Pyrite-based trace element fingerprints for methane and oil seepage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6083, https://doi.org/10.5194/egusphere-egu24-6083, 2024.

EGU24-8617 | ECS | Orals | ERE4.8

What can we learn from pyrite about the hydrogeology of argillaceous formations? 

Marie Bonitz, Theresa Hennig, Anja Schleicher, Christof Kusebauch, David Jaeggi, and Michael Kühn

Argillaceous rock formations provide favourable properties to act as geological barriers for the disposal of high-level radioactive waste. Opalinus Clay is the chosen host rock in Switzerland and is also being considered in Germany. Pyrite is an ubiquitous mineral found in most argillaceous rock formations, and is also present in the Opalinus Clay and its adjacent units. For the long-term integrity of the disposal site, temporally and spatially stable geochemical conditions are essential. Pyrite might be one essential indicator how the sediment formation is influenced by surrounding aquifers. The appearance and composition of pyrite has been used to investigate different geological processes, such as depositional and diagenetic settings, paleoredox conditions and enrichment processes. The geochemical and mineralogical changes in rock formations provide information about processes in the past, and thus enable an assessment for the future. In this context the detailed analysis of pyrite might be a useful tool.

In May 2023, two boreholes were drilled (15 and 25 m deep) in the Mont Terri underground laboratory to investigate the water-bearing members of the Staffelegg Formation (Toarcian-Sinemurian) underlying the Opalinus Clay (Toarcian). The focus was hereby on the transition zones between the permeable and non-permeable rocks to detect alteration reactions and mobilisation processes. In addition to the analysis of the bulk mineralogy and geochemistry, pathways of groundwater and fracture zones have been investigated by analysing thick sections with X-ray and microscopic methods.

Two groundwater paths have been identified in the Staffelegg Formation with fracture zones and their fillings. Calcite and barite are distinguishable and represent two generations, revealing a change of the groundwater composition with supersaturation at different points in time. Therefore, the hydrogeological system experienced at least two events of advective transport. The analysis of pyrite addresses the question to which extent these events have altered and infiltrated the formations.

Pyrite has been formed diagenetically and potentially syngenetically and is present in varying morphologies: μm- to cm-sized euhedral crystals, framboids and nodules. The size and morphology of diagenetic pyrites provide information about the transport processes in the sediment. Euhedral crystals are found in diffusion dominated systems. Accumulations of microcrystals reflect conditions providing an initial nucleation burst, but further crystal growth is limited by restricted supply of Fe and S as it occurs in diffusion-limited regimes with minor advection. Nodules can form in gently advective or stagnant systems with good nutrient supply. The types of pyrite close to fractures and transition zones is used to characterize the predominant transport process at this position.

Diagenetic carbonates and sulphide or sulphate minerals control the concentration of major cations, and redox reactions. Therefore, they provide information about the succession of processes from deposition, to diagenesis, mobilisation and alteration. Their analysis has the potential to assess the long-term integrity of the Opalinus Clay as a host rock and the surrounding formations. The gained understanding of the hydrogeological influence on the geochemical conditions is to be transferred to other potential disposal sites in argillaceous formations.

How to cite: Bonitz, M., Hennig, T., Schleicher, A., Kusebauch, C., Jaeggi, D., and Kühn, M.: What can we learn from pyrite about the hydrogeology of argillaceous formations?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8617, https://doi.org/10.5194/egusphere-egu24-8617, 2024.

EGU24-9060 | Orals | ERE4.8

Quantifying key drivers of marine pyrite content and isotopic composition 

Jordon Hemingway, Cornelia Mertens, and Sarah Paradis

Microbial sulfate reduction (MSR) and subsequent pyrite burial in marine sediments plays a crucial role in Earth’s long-term carbon and oxygen budgets; by reducing sulfate and producing alkalinity, this process effectively increases atmospheric O2 and lowers CO2 levels. Given that MSR exhibits a large and reduction-rate-dependent sulfur-isotope fractionation, changes in pyrite sulfur-isotope compositions (δ34S values) through geologic time have long been interpreted to reflect global signals such as marine sulfate reduction rates, microbial community behavior, and the amount of sulfur buried as pyrite vs. evaporite minerals. However, recent research has demonstrated that marine MSR fractionation likely operates near an equilibrium limit regardless of reduction rate. These studies instead implicate local environmental and sedimentological factors as drivers of pyrite δ34S values. Despite this advancement, the sensitivity of pyrite formation rate and δ34S value to changes in environmental and sedimentological variables—both today and through geologic time—remains unconstrained due to the complex interactions between controlling variables.

To provide mechanistic and quantitative constraints, we developed and applied a non-dimensional diagenetic model that extracts the natural variables governing pyrite formation. Assuming equilibrium MSR isotope fractionation and using only locally measured or globally interpolated boundary values as inputs (i.e., no free parameters), our model accurately predicts all available modern observations (n = 216 cores) with an average root-mean square error of 0.3 wt % for pyrite content and 16.5 ‰ for δ34S. Extrapolating this result, we estimate global pyrite burial flux to be ~1.3 × 1012 mol FeS2 yr−1 with a weighted-average δ34S value of ~-21 ‰ VCDT.This flux is statistically identical to independent estimates of total riverine sulfate input (i.e., pyrite-oxidation and evaporite-dissolution derived), indicating the sulfur cycle currently operates in steady state. However, calculated pyrite burial exceeds pyrite-oxidation derived inputs, suggesting net atmospheric O2 release and CO2 consumption by the sulfur cycle.

Mechanistically, we conclude that pyrite formation rate is highly sensitive to local reactive iron input, whereas δ34S value is primarily controlled by organic carbon reactivity-to-sedimentation rate ratio (termed Da*, a modified Damköhler number) and organic carbon-to-sulfate ratio (termed Γ0). In contrast to previous models, we show that pyrite δ34S is largely insensitive to bioturbation due to counter-balancing impacts on Da* and Γ0. Rather, when combined with a geologic pyrite δ34S record, our interpretation requires an increase in Da* and decrease in Γ0 since the Paleozoic, possibly driven by changing organic matter reactivity and sulfate concentration through geologic time.

How to cite: Hemingway, J., Mertens, C., and Paradis, S.: Quantifying key drivers of marine pyrite content and isotopic composition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9060, https://doi.org/10.5194/egusphere-egu24-9060, 2024.

EGU24-14930 | ECS | Posters on site | ERE4.8 | Highlight

Microbial Pyrite Oxidation and Chemical Weathering to a Typhoon Precipitation and Discharge Event in Taiwan 

Jui-Ming Chang, I-Feng Wu, Li-Hung Lin, Aaron Bufe, Pei-Ling Wang, Hsi-Ling Chou, Niels Hovius, and Tung-Chou Hsieh

Microbially mediated pyrite oxidation is considered a crucial element of the global weathering engine. However, observations of bacterial pyrite oxidation in nature remain scarce due to limited field sampling, particularly during typhoon precipitation and discharge events. In this study, we present a time series of water chemistry at three-hour intervals from the Sinwulyu River, southeast Taiwan, across the typhoons Nesat (0-27th hours) and Haitung (30th-60th hours) in 2017. The cumulative precipitation for the two typhoons ranged from 18 to 78 mm and 59 to 227 mm in the catchment, resulting in discharge increases from 6 to 122 c.m.s. and 53 to 1,207 c.m.s. at the catchment's outlet. The Sinwulyu River drains a catchment underlain by metamorphosed passive-margin sediments that are rapidly exhuming. Integrating measurements of major ions, δDH2O, δ18OH2O, δ34SSO4, δ18OSO4, and simulations of discharge, we find dynamic changes in the source of solutes to the stream water across the typhoons. Our findings indicate that all chemical solutes experienced dilution by 30-80% during typhoon discharge. δDH2O and δ18OH2O values were more negative with increasing discharge, suggesting that the discharge is driven by a combination of precipitation and groundwater injection into the river. δ34SSO4 and  δ18OSO4 ranged from -3.9 ‰ to -7.1 ‰ and from -1.9 ‰ to -6.5 ‰, respectively, suggesting that the majority of riverine sulfate is sourced from oxidative weathering of pyrite. In addition to variations of the water chemistry, we also found substantial changes in the concentrations of sulphur-oxidizing bacteria, Thiobacillus and, Sulfuricurvum (anaerobic microorganisms) emerged as the dominant genera during typhoons. The peak concentration of Thiobacillus occurred at the first typhoon at the 27th hour (1.17×107 copies/L), while Sulfuricurvum peaked at the 48th hour during the second typhoon (2 hours before peak discharge) with a concentration of 2.32×108 copies/L, coinciding high ranges of sediment concentrations and representing 241 and 1,570 times the background level before typhoons, respectively. Both peak concentrations were sudden appearances, indicating that some pools of concentrated microorganisms were quickly depleted by typhoon precipitation/discharge. Notably, the highest abundance of Sulfuricurvum coincided with an increase in chemical solutes. As the discharge rose from 714 to 1,092 c.m.s. (45-48th hour), the concentration of sulfuricurvum increased around tenfold, coupled with an 8%, 7%, and 7% increase in the concentrations of SO4-2, Ca+2, and Mg+2, respectively. However, other chemical solutes maintained a similar concentration. These observations suggest the typhoon mobilized a specific reservoir of elevated pyrite oxidation for carbonate weathering under anaerobic conditions. Through discharge simulation, the high concentration of solute and Sulfuricurvum mobilized substantially at hourly precipitation rates of over 20 mm/hr. We propose that an ample amount of precipitation is essential to flush out the previously inaccessible pool with anaerobic bacterial pyrite oxidation and subsequent carbonate weathering in the stream.

How to cite: Chang, J.-M., Wu, I.-F., Lin, L.-H., Bufe, A., Wang, P.-L., Chou, H.-L., Hovius, N., and Hsieh, T.-C.: Microbial Pyrite Oxidation and Chemical Weathering to a Typhoon Precipitation and Discharge Event in Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14930, https://doi.org/10.5194/egusphere-egu24-14930, 2024.

EGU24-15524 | ECS | Orals | ERE4.8

Pyrite trace element proxies for magmatic volatile influx in submarine subduction-related hydrothermal systems 

Jan J. Falkenberg, Manuel Keith, Karsten M. Haase, Reiner Klemd, Martin Kutzschbach, Anna Grosche, Maria Rosa Scicchitano, Harald Strauss, and Jonguk Kim

Seafloor massive sulfides represent modern analogues to ancient volcanogenic massive sulfide deposits, which can be particularly enriched in volatile and precious metals (e.g., Te, Au, Ag, Cu, Bi, Se) in subduction-related systems. However, it remains unclear whether the influx of magmatic volatiles has a systematic control on the metal endowment of submarine hydrothermal mineralization on the plate-tectonic scale. Using a novel microanalytical approach based on the coupling of SIMS δ34S with trace element LA-ICP-MS on a scale of ~25 µm in pyrite from 11 submarine hydrothermal systems, we could demonstrate for the first time that the Te, As, and Sb contents and the ratios of these elements vary systematically with the δ34S composition of hydrothermal pyrite and native S. In contrast to trace element concentrations, Te/As and Te/Sb show a more significant correlation with δ34S in pyrite, indicating that element ratios provide a more robust record of metal sourcing. On this basis, we define a quantitative trace element threshold of high Te/As (>0.004) and Te/Sb (>0.6) ratios in pyrite that can be used to identify the influx of magmatic volatiles to submarine subduction-related hydrothermal systems independent of δ34S isotope measurements. Two-component fluid mixing simulations further suggest that even small amounts (<0.5 to ~5%) of magmatic volatile influx drastically change the Te/As (and Te/Sb) ratio of the modelled fluid, but only slightly modify its δ34S composition. Hence, Te/As and Te/Sb ratios are more sensitive in recording the influx of magmatic volatiles into submarine hydrothermal systems than S isotope systematics, which are typically influenced by seawater-derived S leading to ambiguous δ34S signatures. We conclude that Te/As and Te/Sb systematics in pyrite provide a robust proxy to evaluate the metal sources in submarine hydrothermal systems from the grain to plate-tectonic scale.

How to cite: Falkenberg, J. J., Keith, M., Haase, K. M., Klemd, R., Kutzschbach, M., Grosche, A., Scicchitano, M. R., Strauss, H., and Kim, J.: Pyrite trace element proxies for magmatic volatile influx in submarine subduction-related hydrothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15524, https://doi.org/10.5194/egusphere-egu24-15524, 2024.

EGU24-15652 | ECS | Orals | ERE4.8

The role of pyrite surface area and thermochemical sulfate reduction in clastic-dominant Zn Deposits.  

Peter Berger, Joseph Magnall, Michael Kühn, and Sarah Gleeson

It is vital to keep up with the demand for critical minerals during the transition to sustainable energy systems. Doing so requires expanding our knowledge of ore depositional processes. Pyrite is a common gangue mineral in clastic dominated (CD) deposits, which are the highest value Zn deposits. In CD-type deposits, pyrite is often part of the pre-, syn-, and post-ore paragenesis and can therefore provide an important redox buffer and potentially a source of sulfur during ore deposition. The distribution of syn-ore pyrite beyond economic mineralization can also form an important mineralogical halo around CD-type deposits.

In this study we investigate the role of fluid interaction with different types of pyrite on ore formation in the Teena deposit (Australia). The host unit for the Teena deposit is an organic rich, variably pyritic, dolomitic siltstone. We created a series of 2D, reactive transport models using the software X2t (Geochemists Workbench) to investigate the role of pyrite surface area as a major control on ore deposition.

Similar to many CD-type deposits, the main type of pre-ore diagenetic pyrite in the host unit is framboidal, which has a high surface area, whereas syn-ore generations of pyrite tend to be coarser grained. In the models, pyrite surface area was varied from 100 (syn-ore) to 10,000 cm2/g (diagenetic). Organic matter provided a drive for thermochemical sulfate reduction (TSR) in the models, and TSR rates were varied over several orders of magnitude in accordance with laboratory measured values.

As the incoming hydrothermal fluid reacted with the host unit, pyrite and dolomite are dissolved and sphalerite is precipitated. The surface area of pyrite evolved as it dissolved and reprecipitated in the form of a more massive, lower surface area, hydrothermal pyrite.

Models using the higher surface area values for diagenetic pyrite resulted in more compact and higher grade ore deposition. The pyrite at the inlet in this scenario dissolved completely. As the pyrite reprecipitated, it formed more extensive halo ahead of the sphalerite reaction front than in models using the lower hydrothermal surface area. Slower rates of TSR also broadened the pyrite halo and decreased the sphalerite ore grade. Low pyrite surface area coupled with low TSR rates resulted in a disseminated deposit. Based on these results, the paragenetic evolution of pyrite over the course of hydrothermal alteration and the resulting changes in surface area are an important control on ore grade and the extent of halo formation.

How to cite: Berger, P., Magnall, J., Kühn, M., and Gleeson, S.: The role of pyrite surface area and thermochemical sulfate reduction in clastic-dominant Zn Deposits. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15652, https://doi.org/10.5194/egusphere-egu24-15652, 2024.

EGU24-21083 | Orals | ERE4.8 | Highlight

The shelf life of pyrite - effects of pyrite weathering in exposed continental shelves on global CO2 and O2 

Martin Kölling, Ilham Bouimetarhan, and Matthias Zabel

During times of low sea-levels in glacials there is evidence of large-scale pyrite oxidation on exposed continental shelves. While this process directly reduces atmospheric oxygen levels, acid drainage generated by this reaction increases the release of CO2 through carbonate buffering within the previously marine shelf sediments. Although this scenario is expected to result in negative feedback, sea-level and atmospheric CO2 levels have co-varied throughout most of the last 800 thousand years (ka) for which direct records of CO2 exist. Only during peak glacial conditions with sea-levels as low as 125 m lower than today, CO2 levels have reached an apparent lower limit around 190 ppm independent of decreasing sea-levels. Here we show that pyrite driven release of CO2 and decline of O2 during six of the last nine glacial-interglacial cycles are focussed in 10 ka to 40 ka-long periods preceding glacial terminations.

Using a sea-level driven model of pyrite weathering in drained continental shelves, we demonstrate that repeated sea-level low-stands force pyrite oxidation to ever greater depths. This occurs whenever the duration of an interglacial is insufficient to restock the shelf pyrite inventory through sulphate reduction in the shelf sediments. During the Quaternary, the decreasing amount of pyrite in the exposed shelf sediments represents a discharging 'acid capacitor' (Kölling et al., 2019). This model was inspired by experience from modelling pyrite weathering in open-pit lignite mine overburden material which may be interpreted as a scaled-down model of glacial continental shelf exposure during sea-level low-stands.

If pyrite oxidation forced CO2 release specifically at low sea-levels was sufficient to amplify the orbitally driven climate forcing and trigger glacial terminations, the absence of CO2 release caused by exposed pyrite rather than an astronomically controlled '100 ka pacing' might have extended the length of glacial-interglacial cycles from one to two or three obliquity cycles. Future ocean drilling specifically aiming to recover long cores on shelves could reveal the existence of a 'pyrite gap' that should exist between surficial young pyritic layers and deeper old pyritic sequences with indications of acid leaching.

 

Kölling, M., Bouimetarhan, I., Bowles, M.W. et al. Consistent CO2 release by pyrite oxidation on continental shelves prior to glacial terminations. Nat. Geosci. 12, 929–934 (2019). https://doi.org/10.1038/s41561-019-0465-9

How to cite: Kölling, M., Bouimetarhan, I., and Zabel, M.: The shelf life of pyrite - effects of pyrite weathering in exposed continental shelves on global CO2 and O2, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21083, https://doi.org/10.5194/egusphere-egu24-21083, 2024.

The formation of pyrite has been extensively studied because of its abundance in many anoxic environments such as marine and river sediments, groundwater aquifers, and peat lands, and hence its importance in both iron and sulfur cycling. It forms over a wide pH interval, ranging from acidic to alkaline. It is generally regarded that sulfide reacting with iron-containing minerals forms metastable iron sulfide minerals before eventually transforming into pyrite in the presence of different sulfur.

In this contribution, I will discuss the importance of sulfidation of ferric (oxy)hydroxides (FeOOH), i.e. the reaction between aqueous sulfide and the surface of FeOOH, to stimulate pyrite formation and compare this process with other pathways and kinetics of pyrite formation described in the literature. Sulfidation of FeOOH initially leads to formation of surface bound FeS-species and its transformation to pyrite is controlled by either the availability of FeOOH or the supply rate of sulfide. These kinetic constraints define the environments were rapid pyrite formation occurs to be suboxic, rich in FeOOH and shaped by cryptic sulfur cycling. Under these conditions, highly reactive pyrite precursor species are forming that also affect trace metal cycling.

How to cite: Peiffer, S.: Controls on recent pyrite formation in aquatic systems and its relevance for environmental processes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21260, https://doi.org/10.5194/egusphere-egu24-21260, 2024.

EGU24-21310 | Posters on site | ERE4.8

Partitioning of trace elements between hydrothermal fluids and pyrite 

Christof Kusebauch, Joseph Michael Magnall, and Sarah Gleeson

Pyrite is the most abundant sulfide on Earth and can host a large variety of trace elements including Au, Co, Mo, Cu, Pb, As, Se, Te, Bi and Sb. Trace element variations in pyrite have been used to study various processes during ore formation, to reconstruct paleo-seawater composition and to understand hydrothermal systems. Furthermore, element enrichment in pyrite can reach high enough concentrations that pyrite itself becomes an ore mineral and can be mined. For example, the enrichment of Au in As-bearing pyrite can reach up to several thousand ppm in the giant Au deposits of the Carlin trend (Nevada, USA). In this case the coupled partitioning of Au and As is considered to be an ore forming process1. The high variability of trace elements in pyrite makes it potentially a powerful tool for the reconstruction of fluid compositions in hydrothermal settings. Nevertheless, the lack of partition coefficients of trace elements between hydrothermal fluids and coexisting/newly forming pyrite hinders a wider use of pyrite as a fluid proxy. Also, the underlying processes controlling the incorporation into the crystal structure and the interplay of different trace elements during partitioning are not well understood.

Here, we present results of hydrothermal batch experiments at 200°C studying the partitioning of Co, Cu, Pb, Se, Bi, As and Sb between aqueous solutions and newly formed pyrite. We use the replacement of siderite to crystalize euhedral pyrites large enough to be measured by LA-ICPMS for their trace element content2. The initial trace element concentration in the experimental fluid varied from 0.1 to 10 ppm. To study the influence of As in pyrite on the D values, As concentration in the experiments was varied independently, whereas all other tracers had a constant ratio. 

Concentrations of trace elements in hydrothermal pyrite range between 10 ppm and 1200 ppm, and depend strongly on the initial fluid composition. Partition coefficients for Sb and Se are in the range of 20-300. Co, Cu, Pb, Bi have lower but more variable D values ranging from 0.1 up to 50. Almost all studied elements show a high compatibility in the pyrite structure, replacing most likely either S (i.e, Se, Sb) or Fe (i.e., Co, Cu, Bi, Pb) in the crystal lattice. Unlike Au, partitioning of studied trace metals is not coupled to the As concentration of newly formed pyrite. Nevertheless, D values of Co, Cu, Se and Sb from experiments with a high concentration of trace elements (i.e., 10 ppm) decrease compared to D values from experiments done at lower concentrations (i.e. 0.1 and 1 ppm). This behavior indicates either a solubility limit of the particular element in the pyrite structure or results from an over-occupation of the potential crystal sites by other trace elements. The partition data from our experiments will help to unlock the potential to use the pyrite composition as a proxy for hydrothermal fluids.      

 

References:

1 Kusebauch et al., (2019) SciAdvances; 10.1126/sciadv.aav5891

2 Kusebauch et al., (2018) Chemical Geology; 10.1016/j.chemgeo.2018.09.027

How to cite: Kusebauch, C., Magnall, J. M., and Gleeson, S.: Partitioning of trace elements between hydrothermal fluids and pyrite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21310, https://doi.org/10.5194/egusphere-egu24-21310, 2024.

EGU24-21650 | ECS | Orals | ERE4.8

Geochemical interactions of Np and Pu with pyrite heterogeneities in Opalinus Clay in the context of deep geological repositories 

Markus Breckheimer, Samer Amayri, Dario Ferreira Sanchez, Daniel Grolimund, and Tobias Reich

The safety case for the final disposal of high-level radioactive waste in a deep geological repository involves a thorough understanding of the geochemical interactions of the potentially mobilized waste inventory with components of a proposed multi-barrier concept.

Argillaceous rock is considered as a potential host rock and final barrier to the biosphere. Opalinus Clay (OPA) from the Mont Terri rock laboratory (St-Ursanne, Switzerland) serves as a reference material for a natural clay rock. As a sedimentary rock and porous medium, OPA exhibits characteristic properties such as a low hydraulic conductivity, limiting the transport of solutes to diffusion, as well as structural and compositional heterogeneities in a range of length scales [1].

To address the influence of the potentially reactive microstructure on solute transport, spatially resolved sorption and diffusion studies of Np(V) and Pu(V,VI) with bulk OPA samples were performed, utilizing synchrotron-based microscopic chemical imaging at the microXAS beamline (Swiss Light Source, Paul Scherrer Institute, Villigen, Switzerland), simultaneously obtaining chemical information about the OPA microstructure as well as the distribution and transport patterns of Np and Pu [2-5].

In these studies, domains of pyrite, contained in OPA to about 1 wt. % as microstructural, Fe(II)-bearing heterogeneities, were identified exhibiting an enhanced reactivity regarding redox transformation and immobilization of the solute species as reduced, predominantly tetravalent and therefore less mobile species.

Further sorption studies with isolated pyrite heterogeneities, extracted from the OPA matrix as sub-100 µm sized particles, indicate a reactivity depending on the morphology of the heterogeneities, including the crystallite size distribution (framboidal) and cementing phase of these pyrite aggregates.

The results of these studies should add to an enhanced understanding of reactive transport in a natural clay rock in the context of a deep geological repository.

 

References

[1] Nagra (2002). Tech. Ber. 02-03. Projekt Opalinuston. Wettingen, Switzerland.

[2] Fröhlich, D.R., Amayri, S., Drebert, J., Grolimund, D., Huth, J., Kaplan, U., Krause, J. and Reich, T. (2012). Speciation of Np(V) uptake by Opalinus Clay using synchrotron microbeam techniques. Anal. Bioanal. Chem. 404: 2151-2162.

[3] Kaplan, U., Amayri, S., Drebert, J., Rossberg, A., Grolimund, D. and Reich, T. (2017). Geochemical interactions of Plutonium with Opalinus Clay studied by spatially resolved synchrotron radiation techniques. Environ. Sci. Technol. 51: 7892-7902.

[4] Börner, P.J.B. (2017). Sorption and diffusion of Neptunium in Opalinus Clay. PhD thesis. Johannes Gutenberg-Universität Mainz, Mainz, Germany.

[5] Kaplan, U., Amayri, S., Drebert, J., Grolimund, D. and Reich, T. (2024). Plutonium mobility and reactivity in a heterogeneous clay rock barrier accented by synchrotron-based microscopic chemical imaging. Sci. Rep., accepted.

 

Acknowledgements

Funding from the German Federal Ministry of Education and Research (BMBF) under contract number 02NUK044B, from the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV) under contract numbers 02E11415A and 02E11860A, and from the European Union’s Horizon 2020 project EURAD (WP FUTuRE), EC Grant agreement no. 847593, is acknowledged.

How to cite: Breckheimer, M., Amayri, S., Ferreira Sanchez, D., Grolimund, D., and Reich, T.: Geochemical interactions of Np and Pu with pyrite heterogeneities in Opalinus Clay in the context of deep geological repositories, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21650, https://doi.org/10.5194/egusphere-egu24-21650, 2024.

EGU24-21668 | ECS | Orals | ERE4.8

Pyrite oxidation rates and timing of weathering in supergene deposits: new insights from XPS approach 

Julien Poot, Alexandre Felten, Julien L. Colaux, Rachel Gouttebaron, Guillaume Lepêcheur, Gaëtan Rochez, and Johan Yans

Pyrite is one of the most common sulfides on Earth and occurs in many Cu, Pb and Zn sulfides (hypogene) ore deposits. By using XPS (X-ray Photoelectron Spectroscopy) surface and depth analyses, we propose a new experimental approach to determine the oxidation rate of pyrite in three exposure/conditions: i) air, ii) water and iii) water drip (Figure 1). Pyrite samples are almost pure and were collected from the Danube–Bouchon quarry (Hautrage, Belgium), in Barremian black clays of the Wealden facies sediments in the Mons Basin. These pyrites are nodules with cubic aggregates on the surface which were used for the different experiments.

The results reveal a maximum oxidation rate of 11.7 ± 1.8 nm day−1 for drip exposure associated with the precipitation of Fe-sulfates or/and oxides depending on the experimental conditions. These data can be extrapolated to the different zones of weathering profiles (gossan, saprolite and cementation zone). The extrapolation shows a maximum rate of 4.3 ± 0.6 m Ma−1, values consistent with those obtained by other methods such as isotope dating of weathering profiles (e.g. [1,2]). The oxidation in natural systems can vary following different factors, such as the nature of the host rock (protore) and the primary mineralogy, the porosity/permeability and fractures, the presence of an oxidizing environment, climate change over time, the action of bacteria as catalysts, …

Figure 1 - Macroscopic evolution of pyrite oxidation over time in the different experiments [3]

 

References

[1] De Putter T, Ruffet G, Yans J, Mees F (2015) Ore Geol Rev 71:350–362. https://doi.org/10.1016/J.OREGEOREV.2015.06.015

[2] Vasconcelos PM, Conroy M (2003) Geochim Cosmochim Acta 67:2913–2930. https://doi.org/10.1016/S0016-7037(02)01372-8.

[3] Poot J, Felten A, Colaux JL, Gouttebaron R, Lepêcheur G, Rochez G, Yans J (2024) Environ Earth Sci 83:9. https://doi.org/10.1007/s12665-023-11325-z

How to cite: Poot, J., Felten, A., Colaux, J. L., Gouttebaron, R., Lepêcheur, G., Rochez, G., and Yans, J.: Pyrite oxidation rates and timing of weathering in supergene deposits: new insights from XPS approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21668, https://doi.org/10.5194/egusphere-egu24-21668, 2024.

EGU24-21967 | Posters on site | ERE4.8

Pyrite in Dutch peat - influence of  paleoenvironment and current land use  

Alwina Hoving, Josh Guyat, Thilo Behrends, and Jasper Griffioen

Peatlands in the Netherlands contain high amounts of sulfur (S). Drainage of these peatlands has led to oxidation of the peat, more recently enhanced through extended drought periods from the result of climate change. Oxidation of peat leads to the mobilization of S and elevated sulfate levels in surface waters. High sulfate concentrations are considered a water quality problem and can enhance eutrophication. In this study, the S content and S speciation in Dutch peats were investigated and their relation to paleoenvironment and current land-use.

Peat samples from eight locations in an east-west section, varying over paleoenvironment, peat type, proximity to the River Rhine and the North Sea, and current land‑use were analyzed. Sequential sulfur extraction was performed to fractionate iron-monosulfide, pyrite and organic-bound sulfur. Porewater was analyzed for sulfate, iron and nitrate concentrations to investigate their influence on the S speciation.

The analytical results could be split into 3 groups. The first group consisted of peats of marine paleoenvironment which had the highest total S content. Due to limited availability of iron (Fe), sulfur was predominantly present as organic-S and <10% of S was present as pyrite. Group 2 consisted of peat from fluvial paleoenvironment origin. In these groundwater fed, nutrient rich, minerotrophic fens, pyrite made up a larger portion of total S. In group 3, the peat was influenced by the river ‘Oude Rijn’. This river was polluted with higher sulfate concentrations, relative to rain water, and also carried clay particles rich in ferrous iron. Flooding events brought Fe to the peat-forming system resulting in pyrite formation. The influence of land-use was only visible in the top layers; high concentrations of nitrate in combination with a low pyrite content and elevated sulfate concentrations were likely caused by the input of fertilizer and subsequent denitrification and oxidation of pyrite.

Overall, paleoenvironment was found to be the predominant factor controlling S content and S speciation in Dutch peats in the Western Netherlands. Particularly the presence of pyrite was related to the presence of fen reed peats and dependent on a nearby Fe source during peat formation.

How to cite: Hoving, A., Guyat, J., Behrends, T., and Griffioen, J.: Pyrite in Dutch peat - influence of  paleoenvironment and current land use , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21967, https://doi.org/10.5194/egusphere-egu24-21967, 2024.

Due to the action of intrinsic and extrinsic factors, such as mineralogical compositions, textures, weathering, climatic conditions and pollution in urban centers, constructions using stone that are part of a country's cultural heritage require permanent care for their preservation, which must involve collaboration between professionals from different areas of knowledge. The case presented here serves as an example of a conservation action developed after unprecedented work involving the participation of geologists and a biologist and confirms that an interdisciplinary approach is indeed essential to guarantee a holistic understanding of stone in buildings. The cultural asset treated consists of a sculptural set made up of twelve life-size statues, representing prophets. Produced between 1800 and 1805, the set was built using inhomogeneous steatite blocks, ranging from isotropic to anisotropic types and is part of a monument located in the city of Congonhas, Minas Gerais, Brazil. Recognized by UNESCO as a Cultural Heritage of Humanity, the complex suffers degradation of different types, with emphasis on the natural and recurring action of biological colonization, which motivated this interdisciplinary work. At the beginning of 2023, after twelve years without any intervention, the elements of the complex appeared almost completely taken over by biological colonization, which caused visible aesthetic degradation, compromising the religious function for which they were produced. Initially, a detailed macroscopic petrography of all the statues was carried out, seeking to identify the different textures present in the steatite blocks used, but also all types of stone degradation. In addition to biological colonization represented by the presence of cyanobacteria, algae and lichens, losses of pieces, black crusts, dissolutions, patinas and cracks were observed. Of the mentioned microorganisms, mainly whitish gray or greenish lichens were found, described as foliaceous and other whitish lichens forming crusts on the substrate and described as crustose. Algae without stems or leaves and showing colors varying between yellow, green and reddish brown were also observed, occurring in a subordinate manner in relation to lichens. Other forms, such as mosses, were observed filling cavities and developing along fissures and fractures in the stone, as well as in spaces between blocks and between the bases of statues. Following our assessments on the extent of degradation of the stone material and the respective degree of deterioration of the set of statues, procedures were adopted by the conservators of the company Grupo Oficina de Restauro aiming to combat microorganisms with applications of a biocide and 70% alcohol. Geological monitoring during the microorganism removal process, evaluating possible losses to the stone substrate, and a new macroscopic petrography carried out sixty days later confirmed the absence of new damage to the stone. In summary, the presence, especially of geologists, who know the properties of the stone materials present in buildings, particularly historic ones, was fundamental to the success of the conservation action, which must always have a multidisciplinary character.

How to cite: Costa, A. G.: Stone science and its importance for the adoption of conservation actions: an example of interdisciplinary work in Brazil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4362, https://doi.org/10.5194/egusphere-egu24-4362, 2024.

EGU24-13460 | ECS | Posters virtual | ERE4.11

Identification of deterioration factors and diagnosis of the “Dar lqadi” or “Bîmâristân de Sala” facade, Sala, Morocco. 

Siham Belhaj, Omaima Esssaad Belhaj, Aziz Rhffari, and Boutaina Erraoui

The mâristân of Sala, better known under the names of Funduq Askour or Dar el Qadi is an ancient medical school located in Sala, Morocco, which was built during the Marinid era in the mid-14th century. In turn mâristân (hospital or hospice), foundouq (caravanserai) then sharia court, it ended up being transformed into a traditional music museum.
The mâristân of Sala was built according to Andalusian architecture, in this work we will dissect the architectural layout of the building firstly then we will identify the traditional construction materials that exist on the site such as calcarenite stone, zellige, wood, to then identify the damage that has affected these materials as well as their production processes.

How to cite: Belhaj, S., Belhaj, O. E., Rhffari, A., and Erraoui, B.: Identification of deterioration factors and diagnosis of the “Dar lqadi” or “Bîmâristân de Sala” facade, Sala, Morocco., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13460, https://doi.org/10.5194/egusphere-egu24-13460, 2024.

EGU24-13508 | Posters on site | ERE4.11

Almadén de la Plata marble: a Heritage Stone Proposal 

Luis Lopes, Jose Beltran, Esther Ontiveros, Noel Moreira, Maria Luisa Loza, and André Carneiro

Almadén de La Plata marble is located in Ossa-Morena Zone (Iberian Massif) and generated through Variscan metamorphism of Cambrian limestones, being exploited during the Roman period. They were used in a wide variety of ways, such as architectural elements and decoration, statuary, and epigraphic monuments. The quarries for these marbles did not reach the dimensions found in other places (i.e., Vila Verde de Ficalho, Rosal de la Frontera, Alconera, Fuenteheridos-Navahermosa and Aroche), where they were exploited until the 20th century and where they continue to be exploited (Estremoz, Trigaches, Viana do Alentejo) until our days. Perhaps for this reason, the Roman quarries have survived to this day with an exceptional state of conservation, allowing the perception of what a marble quarry would have been like in the Roman period, as well as the methods and techniques used in the extraction of blocks which can also be observed.

The geological area of Almadén de la Plata marble, which comprises two main ancient exploitation places (Cerro de Los Covachos Quarry, which was completely excavated and musealized for public exhibition, and the Cerro Loma de Los Castillejos quarry), is spatially limited, being located near the E-W direction suture zone between the Ossa-Morena Zone and South Portuguese Terrane.

The marbles appear in the foot-wall of a calco-silicate series, being predominantly calcitic, although there are also dolomite-rich marbles with sigificant input of silicate minerals. Silicate phases are commonly micas, quartz, diopside, plagioclase and olivine, among others, which indicates that they have been subjected to amphibolite facies metamorphism.

Studies by several authors reports that the marble of Almadén de la Plata reached western areas of the Baetica Roman province (for instance, have been included in a line of research on the monumentalization processes of the Roman towns of: Hispalis, Italica, Astigi, Celti, Carmo, Malaca, among others), but also in other mainland places, such as Segobriga (Saelices, Cuenca) and even cities located in the north African province of Mauretania Tingitana, like Thamusida and Banasa, in present-day Morocco.

On a separate note, we can consider that all occurrences of Palaeozoic marbles from the Ossa-Morena Zone in Portugal and Spain could perfectly be framed within the concept of Heritage Stone Province.

As far as we know, in the short term, no start of modern exploration of the Almadén de la Plata marbles is expected. Still, there are cases of recent application of them, for example there is a typical Almadén de la Plata street, famous for its cobblestone pavement, built by José Antonio Benítez, a local resident, that is tied to different historical events and Almaden’s way of life. In any case, the intensive use of this marble in hundreds of monuments, mainly during the Roman period, with the heritage burden associated with this use, makes Almaden de la Plata Marble, Seville Province – Spain,  an outstanding candidate for Heritage Stone.

Acknowledgments: This work is supported by national funding awarded by FCT - Foundation for Science and Technology, I.P., projects UIDB/04683/2020 and UIDP/04683/2020.

How to cite: Lopes, L., Beltran, J., Ontiveros, E., Moreira, N., Loza, M. L., and Carneiro, A.: Almadén de la Plata marble: a Heritage Stone Proposal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13508, https://doi.org/10.5194/egusphere-egu24-13508, 2024.

EGU24-14896 | Posters on site | ERE4.11

Heritage Stones: IUGS Designation and its relevance 

Gurmeet Kaur

The importance of natural stones in architecture and cultural decoding is being acknowledged by the International Union of Geological Sciences (IUGS). Through its global designation ‘IUGS-Heritage Stone', a natural stone that has been extensively used by humanity for the proliferation of cultures and traditions in the past is based on certain criteria, giving visibility to these significant natural stones. The UNESCO-IGCP Project has been instrumental in funding our projects on Heritage stones for the past ten years. The outcome is amazing, with 32 IUGS designated Heritage Stones and 18 more in pipeline awaiting designation. The Heritage stones widely utilized in monuments with significant cultural inference are being designated through a proper procedure designed by the International Commission on Geoheritage of the International Union of Geological Sciences. The need of the hour is to take along geologists, archaeologists, architects, historians, policymakers, and the masses to preserve the stones and monuments that are custodians of our cultural evolution. This multidisciplinary approach guarantees a comprehensive comprehension of their importance.

In summary, the rich and multidisciplinary field of studying stones in stone-built monuments, their geological characteristics, and their effects on culture and architecture aids in our appreciation of the legacy of many civilizations and offers insights into innovative architecture and sustainable resource management (one of the sustainable development goals of UNESCO). Promoting stone science research is essential to safeguarding these priceless historical and cultural artefacts for future generations.

How to cite: Kaur, G.: Heritage Stones: IUGS Designation and its relevance, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14896, https://doi.org/10.5194/egusphere-egu24-14896, 2024.

EGU24-15151 | Posters on site | ERE4.11

Hunting a phantom quarry “four miles from Metz”: Transboundary trade of Lorraine alabaster in the 16th century  

Wolfram Kloppmann, Arthur Acker, Lise Leroux, and Aleksandra Lipińska

Towards the end of the 16th century, the first known hints emerge that the Lorraine region, and in particular the archbishopric of Metz, was a source of alabaster for sculpture in the principalities and bishoprics of the western part of the Holy Roman Empire. In 1587, a list of available alabaster deposits to be used for the epitaph of Magdalena zur Lippe commissioned  by the Landgrave Georg I of Hessen-Darmstadt, mentions an alabaster quarry “in the land of Lorraine, four miles from Metz” exported as far as to Würzburg in present-day Northern Bavaria. Ten years later, Metz alabaster was ordered for the decoration of the Schnellenberg castle in Westphalia.  

Using geochemical fingerprinting, we found evidence that a common source of alabaster was used in the Metz region and further downstream, in the Mosel and Rhine valleys. Indeed, Alabaster was used broadly from the late 16th century onwards in the major episcopal towns Trier, Bonn and Cologne. We postulate that this “phantom quarry”, so far not identified in our isotopic database of historical European alabaster deposits, is identical with the one mentioned near Metz. Indeed, several alabaster-grade gypsum quarries, still mentioned in 19th century literature, could be found within a range of around 30 km around the town. We will present results of combined archival, geological and geochemical research, conducted in the framework of the Franco-German Materi-A-Net project (https://materi-a-net.uni-koeln.de/en/news/) co-funded by ANR and DFG within the FRAL program.

How to cite: Kloppmann, W., Acker, A., Leroux, L., and Lipińska, A.: Hunting a phantom quarry “four miles from Metz”: Transboundary trade of Lorraine alabaster in the 16th century , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15151, https://doi.org/10.5194/egusphere-egu24-15151, 2024.

EGU24-15902 | Posters on site | ERE4.11

San Lorenzo Church in Turin– A stone exhibition of more than 3 centuries ago 

Paola Marini, Rossana Bellopede, Adriano Fiorucci, and Ilaria Orlandella

The church of San Lorenzo is a ducal chapel located in one the main squares of Torino, whose costruction was due to a promises of the Duke of  Savoia Emanuele Filiberto for its safe after the San Quintino battle won in the day of San Lorenzo in 1557. The expansion works on the church actually began in 1634, but were soon interrupted by the death of Vittorio Amedeo (1637) and the resulting civil war, and only thirty years later, with the call of the mathematician Guarino Guarini, the church construction moved on to the resolution phase. For the dome he renewed schemes with a distant ancestry in Gothic and especially oriental architecture. The works for S. Lorenzo lasted a long time: the church was completed by 1679 and consecrated later only after the architect also designed the main altar.

The innovation of the Church of San Lorenzo is certainly the rich variety of decorative stones that we can admire inside and above all the different methods of use that Guarini managed to implement, changing the intended use, and introducing other particular stones which were, at the time, still unknown in Italy.

The main stones used inside the church, are the different types of Frabosa marble, San Martino marble, Foresto marble, Gassino limestone (Piedmont) and Arzo marble (Switzerland) while in the seven chapels, a very large use of Verde Alpi marble, , together with the bright Giallo Reale in contrast with the two blacks, from Frabosa and Portovenere are present.. The use of a different stone for each imposing pair of columns of the various chapels was also sought after, in this regard the green Alpi, the black Portoro, the Rosso Verona but also the breccia of Seravezza, the Gialletto of Verona and the particular Sicilian Libeccio of Custonaci were used.

Furthermore, from the analysis of the different altar frontals the triumph of the charm of different polychrome marbles, assembled excellently together, in a space of limited dimensions is evident.

Verde Alpi and Giallo Reale together with Arabescato Orobico and Spanish Broccatello, are all in great contrast by the black Frabosa marble.

Petrographic knowledge is fundamental in providing the tools for the preservation of cultural heritage as it allows us to carry out recovery interventions on architectural complexes and ancient art objects, having full knowledge of the material on which we are working, being able to proceed with the restoration or a possible replacement of part of the material, preserving its history, origin and characteristics.

In San Lorenzo the enormous wealth of stones will certainly remain a treasure to be protected over time and the possibility of being able to study their history and lithological provenance remains the most interesting aspect of the work I have carried out.

How to cite: Marini, P., Bellopede, R., Fiorucci, A., and Orlandella, I.: San Lorenzo Church in Turin– A stone exhibition of more than 3 centuries ago, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15902, https://doi.org/10.5194/egusphere-egu24-15902, 2024.

EGU24-17550 | Posters on site | ERE4.11

The Gassino stone in the architecture of Torino (Italy): different features for different uses 

Rossana Bellopede, Alessandro Borghi, Anna D'Atri, Francesca Gambino, Paola Marini, Luca Martire, Giovanna Dino, and Elena Storta

The Gassino Stone, the most widely used carbonate sedimentary rock in Torino until the XIX century, is also known as Calcare di Gassino or Gassino Marble (Borghi et al., 2014). It was quarried from the Torino Hill domain near Torino and its formation can be referred to the Eocene. It is a biocalcirudite containing mainly red algae, macroforaminifera, bivalves, echinoids, and locally abundant intraclasts of biocalcarenites.

Although it has not been exploited for a long time, its occurrence in the city is still considerable. Its uses began in the end of the 1600 till mid 1800 and was installed not only in the churches but also in the historical buildings in plinth, columns, fireplaces and furnishings (Campanino et al., 1991).

It is possible to find applications of this rock in many famous historical buildings of Torino and surroundings such as in the colonnade of the courtyard of the Rectorate of the Torino University, in the portal of Palazzo Carignano, on the façades of the Santa Cristina Church and of the Torino Town Hall of, and in the Basilica of Superga external columns.

In the interior it has been usually installed with polished finishes (for example in the San Lorenzo church in the center of Torino). This kind of surface finishes gives a brownish aspect to the stone, in addition to a sense of compactness. When instead the Gassino stone is installed outdoor, with increasing time of exposure, its colour turns white and the compactness decreases emphasizing the presence of nodules consisting of calcareous red algae and intraclasts surrounded by thin clay seams. The portal of  Palazzo Carignano  represents the best example of the differential decay of this kind of stone outdoors, while the holy eater font in San Lorenzo church is the perfect example of optimal maintenance indoors.

How to cite: Bellopede, R., Borghi, A., D'Atri, A., Gambino, F., Marini, P., Martire, L., Dino, G., and Storta, E.: The Gassino stone in the architecture of Torino (Italy): different features for different uses, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17550, https://doi.org/10.5194/egusphere-egu24-17550, 2024.

EGU24-18704 | Posters on site | ERE4.11

Cobalt enamels through time: arsenic's influence and removal in historical production techniques 

Lisa Bruzzone, Laura Gaggero, Alessandro Zucchiatti, and Judit Molera

The presence of elements associated with cobalt in historical enamels provides relevant information on the minerals used to produce them and their origin.
Starting from around 1520 we witnessed the systematic appearance of arsenic in blue enamels produced in the Mediterranean. Until this date and starting from the 15th century, an arsenic-free cobalt pigment was used instead.
The chemical composition of the two glazes is however compatible, showing in both cases the presence of Ni, Fe, Zn associated with Co.
Both pigments may have been produced using the same cobalt and arsenic minerals: erythrite, smaltite and skutterudite coming from the Erzgebirge region (Gratuze et al., 1996; Soulier et al., 1996). Then, the absence of arsenic in one of the two glazes could be attributable to different production processes like the roasting of the ores, which was used to produce saffron, or to the utilize of different fluxes employed to make the glaze, two cobalt by-products that began to be produced in the Erzgebirge mining district starting from the 16th century (Meltzer, 1716).

Recent studies on skutterudite thermal behaviour (Molera et al., 2021) revealed the difficulty of completely removing arsenic from the mineral, however it cannot be excluded that this element can be more easily removed from other minerals with Co/As ratio greater than 1:3.

This study aimed to replicate historical saffron and enamel recipes on erythrite and clinosafflorite to evaluate the loss of arsenic in the final products.
Several roasting experiments, reaching temperatures up to 1020°C, were performed on mineralogical samples from Bou Azzer (Morocco), even using different fluxes and studying the products obtained through different techniques (XRD, XRF, SEM-EDS). Some diffractions were performed during heating using synchrotron radiation.

With these treatments arsenic was not completely eliminated, but cobalt phases with reduced arsenic content were often obtained. The presence of calcium, sodium, and lead promotes the formation of different arsenates inside the glaze.
Heating clinosafflorite powders up to 1020°C resulted in the formation of cobalt-rich phases and As-Co-Fe-Ca phases. A mixture of CaO and borax with erythrite heated up to 900°C allowed to obtain Co-Fe-Ni oxides and Ca-Co-Na-Ni arsenates. Clinosafflorite roasted with quartz and ash promoted the formation of arsenic-free cobalt phases. The reaction and blue colouring of a quartz grain and the formation of different phases of Co-Na-Ca silicates, Co-Fe-Ni phases and different types of arsenates were obtained by heating clinisafflorite with borax at 1020°C.


REFERENCES
Gratuze, B., Soulier, I., Blet, M., Vallauri, L. (1996): De l’origine du cobalt: du verre à la céramique. Revue d’archèometrìe, 20.
Meltzer, C. (1716): Historia Schneebergensis Renovata. Das ist: Erneuerte Stadt- u. Berg-Chronica Der im Ober-Ertz-Gebürge des belobten Meißens gelegenen Wohl-löbl. Freyen Berg-Stadt Schneeberg.
Molera, J., Climent-Font, A., Garcia, G., Pradell, T., Vallcorba, O., Zucchiatti, A. (2021): Experimental study of historical processing of cobalt arsenide ore for colouring glazes (15 16th century Europe). Journal of Archeological science: reports 36.
Soulier, I., Gratuze, B., Barrandon, J.N. (1996): The origin of cobalt blue pigments in French glass from the bronze age to the eighteen century. Revue d’Archéométrie, 20. 

 

How to cite: Bruzzone, L., Gaggero, L., Zucchiatti, A., and Molera, J.: Cobalt enamels through time: arsenic's influence and removal in historical production techniques, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18704, https://doi.org/10.5194/egusphere-egu24-18704, 2024.

EGU24-19481 | Posters virtual | ERE4.11

Black Markina: an ornamental basque limestone (Spain) 

Laura Damas Mollá, Arantza Aranburu, Arantxa Bodego, Iñaki Yusta, Martin Ladron de Guevara, Andrey Ilin, Iñaki Antiguedad, and Jesus Angel Uriarte

Black Markina is a limestone that has been exploited for more than 100 years as an ornamental and construction stone in the Basque Country (Spain). This stone is of great international interest and is well known for the intense black colour it acquires when it is polished. Nevertheless, in natural outcrops and in construction elements with other finishes the colour that characterises it is more or less dark greyish. 

The Markina Limestone Formation is located in the Basque Arc, to the north of the Basque-Cantabrian Basin. It was formed on a shallow subtropical carbonate marine platform during the Aptian/Albian. The main facies are biomicrites with a dark micritic matrix containing abundant fossils that contrast with the white colour: tabular corals in life position, as well as branching and hemispherical corals and Chondrodonta sp. colonies, rudists and gastropods. These facies are well stratified and sometimes a certain degree of transport is observed. Among these facies, those with few carbonate bioclasts and abundant orbitolines (binders) stand out. These facies correspond to the most commercially valued stone variety due to its more homogeneous black tone. 

The origin of the intense black colour of this lithology has not been resolved: on the one hand, the existence of organic matter disseminated in the matrix (on a microscopic scale) and in the interior of the fossils in the form of masses of pseudovitreous appearance (opaque under the optical microscope) has been confirmed. This organic matter already gives the matrix a dark basic tone. On the other hand, the presence of certain minerals such as nanometric magnetite or cubic and framboidal pyrite disseminated in the matrix, smaller than a micron in size, could be what intensifies the black colour when polished. 

The variety of ornamental stone known as Black Markina florid corresponds to facies with diagenetic features, mainly white, contrasting with the intense black of the matrix. In this sense, a generalised recrystallisation/neomorphism of the fossil remains is recognised and different late fracture systems filled with white calcite crystals also stand out. 

Markina village is an example of the use of local stone as a distinctive feature that defines its landscape. Numerous palaces (Ansotegi, 16th century; Gaitan de Ayala or Patrokua, 17th and 20th centuries), religious buildings (Church of La Merced, 18th century) and other architectural elements such as the sculpture in homage to Juan Antonio Moguel (20th century) or the cobblestones of several streets in the municipality have been preserved. Black Markina can also be recognised in elements from other countries as emblematic as the hall of the Empire State Building or the lectern of the United Nations headquarters, both located in New York, or the Kaaba of Mecca (Saudi Arabia). 

How to cite: Damas Mollá, L., Aranburu, A., Bodego, A., Yusta, I., Ladron de Guevara, M., Ilin, A., Antiguedad, I., and Uriarte, J. A.: Black Markina: an ornamental basque limestone (Spain), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19481, https://doi.org/10.5194/egusphere-egu24-19481, 2024.

EGU24-20567 | ECS | Posters virtual | ERE4.11

The heritage unknown Brazilian marbles 

Nuria Castro, Maria Heloisa Frasca, Antonio Gilberto Costa, and Rosana Elisa C. Silva

Brazilian marble production and exports have grown in the last few years, following the trend of the international stone market to commercially exploit the uniqueness of natural stone as a competitive factor. Natural stone companies are spreading over the territory, in the country of exotic silicate rocks, searching for carbonate ones. It would seem that industrial marble production in Brazil is relatively new. Still, it started in the 19th century, achieving its heyday during the 20th century, followed by progressive decay as technology allowed the exploitation of abundant and more resistant granites. National marbles were used both in new constructions and in old buildings' reforms. Therefore, many heritage buildings in the country are dressed in ‘unknown’ or misidentified marbles. This work intends to give publicity to those materials, outlining the chronology of marble production in Brazil based on extensive bibliographic research and fieldwork. This story begins in the last quarter of the 19th century, when Brazil attracted many skilled European immigrants, primarily Italian, with knowledge of marble and technology, and several carbonate rocks had already been discovered in the country. The first mechanized marble quarries opened around 1870 in the state of Rio Grande do Sul to exploit Neoproterozoic whitish blueish marbles used in several monuments, such as the Conde Porto Alegre statue and, probably, the Municipal Palace, both in Porto Alegre city. Those quarries did not prosper due to the scarce infrastructure and skilled labour. The railway was the real booster for the Brazilian marble industry at the end of the century. As the railways expanded from the capital, new deposits were discovered, and already known others became profitable. That is the case of precambrian black, white and pink marbles of the Itupararanga quarries in São Paulo (ca 1895-1914)  used in the Municipal Theater. Also, the proximity to the railway allowed the success of the quarry, regarded as the first in the country, which opened in 1915 in Mar de Espanha, Minas Gerais. This compact white marble of the Juiz de Fora Complex (2,1 Ga) was called “National White Marble”, a name afterwards given to the one quarried in Italva (produced since 1933) and today to the white of Espírito Santo (produced since 1957). All those white marbles and the one from Paraná were used to build Brasília, the country’s capital. In Minas Gerais, too, in Lagoa Santa, important quarries of various coloured limestones and marbles supplied tiles and ornaments between 1925 and 1980 and cobblestone (still produced) for traditional Portuguese pavement to the whole country. Other representative marbles of that time are the 2,4 Ga Gandarella Formation beautiful red, white, bardiglio and mottled (oncolites) dolomitic marbles that ornament the Caraça Sanctuary and many buildings in Rio de Janeiro and other cities, as does the 2,1 Ga stromatolic meta-dolomite of Ouro Preto. Many other marble quarries opened from then on, being just a few active today (e.g. Santa Catarina, Paraná, Espírito Santo), but the industry movement towards marble quarrying could give adequate materials for heritage restoration.

How to cite: Castro, N., Frasca, M. H., Costa, A. G., and Silva, R. E. C.: The heritage unknown Brazilian marbles, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20567, https://doi.org/10.5194/egusphere-egu24-20567, 2024.

EGU24-21803 | Posters on site | ERE4.11

Denizli Travertine: A Heritage Stone Resource from Western Türkiye  

Mehmet Özkul, Arzu Gul, Tamer Koralay, Hülya Özen, Barış Semiz, and Bahadır Duman

Global heritage stones are natural stones that have been widely used in historical buildings and monuments in the past (hundreds of years, even thousands of years) and are still used and today traded at the national and international level. The aim of this study was to evaluate the characteristics of being a global heritage stone of Quaternary travertines, which are common in the Denizli Basin in Western Türkiye.

The Denizli Travertine, is a widely used as a building stone in the Denizli Basin, from the 2nd century BC in the ancient cities of Hierapolis, Laodicea, Tripolis and Colassae that were the leading settlements of the region. Hierapolis/Pamukkale takes place in the of UNESCO World Heritage list and the First 100 IUGS Geological Heritage Sites. The travertine-dominated buildings have given a privileged feature to the aforementioned ancient cities. In these ancient cities, public buildings such as theatre, agora, bath basilica, monumental fountain, bridge and fortification walls were predominantly built using travertine. Use of the travertine also continued in the buildings of Seljuk period (eg, caravanserai, castle walls) from the 13th century.

Some exposures of the Denizli Travertine of Quaternary age observed in different parts of the Denizli Basin take place either very close to or under the ancient cities. In light and dark colors, their textural properties are extended to a wide range. The main texture types are peloid, bacterial/crystalline dendrite, coated grain, mostly wackestone to packstone, a small amount of grainstone containing plant-derived components. Another type is banded travertine, which occurs as a fissure fill or vein, has a completely crystalline texture and is mostly used for decorative purposes.

Travertines of the region, which were operated for thousands of years, received a geographical indication in 2008 with the name of ‘Denizli Travertine’. Today, it is widely used in many areas such as flooring, wall covering, stair step, countertop, table, coffee table and sculpture. The Denizli Travertine is exported to many countries (e.g. USA, UK, European Union and Middle East countries) both blocks and processed products like slab, tiles, mosaic, etc.). The travertine, which has been widely used in the region in the past, is traded worldwide for the last few decades.

How to cite: Özkul, M., Gul, A., Koralay, T., Özen, H., Semiz, B., and Duman, B.: Denizli Travertine: A Heritage Stone Resource from Western Türkiye , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21803, https://doi.org/10.5194/egusphere-egu24-21803, 2024.

EGU24-652 | ECS | Orals | GMPV6.1

Circular economy in extractive industry: challenge and chance to recover fine particles produced in marble quarries exploitation 

Antonio Tazzini, Francesca Gambino, Marco Casale, and Giovanna Antonella Dino

Stone industry plays a significant role in the global economy. The 2015 production was placed in the order of 82.6 million tons with a percentage of the waste extraction and processing amount to over 70% of the gross quantity. Carbonate stones (such as marble, limestone and travertine) account for 58 % of the whole production of dimension stone, serving as primary materials for construction and ornamental uses since ancient times. Approximately 50% of waste is generated during mining operation and around 15% during processing. The disposal of marble powder, a very fine material produced by the marble industry, is one of today's global environmental problems affecting stone industry. Even if the ultra-fine calcareous particles contained in marble sludge have applications in most major industries, thanks to their chemical and physical characteristics, in most cases these materials are landfilled because of the difficulties in recovering, mainly related to local legislation and lack of appropriate protocols.
The need to reduce the use of non-renewable natural resources and, at the same time, to minimize the negative impacts on the environment, has led to an increasing interest in recovery and recycling, in line with the expressed EU policy in the Europe 2020 strategy to reduce Europe's efficiency and in the EU strategy for sustainable development. The Carrara marble basin is one of the most emblematic cases in the Italian stone industry, and it includes about one hundred quarries of colored and white marble, exploited from Roman times. Even if the new technologies have improved efficiency in quarrying and reduced the production of waste, around 50% of the extracted marbles in the Carrara basin still result in waste. Modern cutting technologies generate greater amount of finer materials and sawing residue, varying in size from sand to silt. Due to this very fine particle, it’s easy to see how this characteristic can cause problems with the stability of landfills, with consequent difficulties for their management. The aim of this research is to provide a comparison between different characteristics of marble fine waste in Carrara, both sludges deriving from quarry-cutting and stone processing, to demonstrate the feasibility of their recovery and utilization in different industrial application (i.e., mineral fillers, high value-CaCO3 products, building sector). The results obtained from analysis are promising and could lead to a possible reuse of the materials, in line with the circular economy approach. The reuse of marble waste can bring the double benefit of giving a new value to this by-product and, at the same time, partially eliminate the environmental problem caused by it. The combination of all these insights could lead to sustainable mining of the ornamental stones industry.

How to cite: Tazzini, A., Gambino, F., Casale, M., and Dino, G. A.: Circular economy in extractive industry: challenge and chance to recover fine particles produced in marble quarries exploitation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-652, https://doi.org/10.5194/egusphere-egu24-652, 2024.

EGU24-948 | ECS | Orals | GMPV6.1 | Highlight

Alternative ways to supply Rare Earth Elements: extractive waste recovery. 

Marco Casale, Xinyuan Zhao, Faten Khelifi, Alessandro Cavallo, Elio Padoan, Ke Yang, and Giovanna Antonella Dino

Rare Earth Elements (REE) are considered to be highly "critical" by the European Commission because the concentration of global supply and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines) and this at a time of increasing geopolitical tensions. According to the European Commission’s assessment, the demand for rare earth elements is expected to increase more than fivefold by 2030. Today, Europe is dependent on imports of these minerals, where China completely dominates the market, a factor which increases the vulnerability of European industry. Alternative sources of REE in Europe, such as recovery of quarrying and processing waste, are being considered.

This research, part of an italian project NODES, wich has received funding (PNRR) from the EU, about circular economy and recovery of mineral waste, focuses on the possibility to recover REE from extractive waste. The investigated area cover Piedmont Region in northern Italy. Waste materials from gneisses and granites (ranging from blocks up to residual sludge) used as dimension stones were characterized for volume, chemistry, mineralogy, and texture.

Based on the first analyses carried out, the most interesting contexts are those related to gneisses in Luserna Stone and Verbano Cusio Ossola quarrying area and to quartzites of Monte Bracco quarrying area.

Thanks to a proper treatment activity (grinding, screening and magnetic separation), these materials, present in past extractive waste facilities and in extractive waste coming from exploitation and working activities, could be used to recovery of REE. After the first phase, connected to “waste” characterisation, the following activities will be linked to processing of the richest samples to exploit (at Laboratory level) REE, and to economic issues.

An additional step will include leaching extraction tests (always at laboratory scale) to identify the best and most sustainable technique to extract and separate REE from the sampled extractive waste.

 

Key words: Rare Earth Elements, Critical Raw Materials, Supply-chain, extractive waste, mining waste, leaching, magnetic separation.

How to cite: Casale, M., Zhao, X., Khelifi, F., Cavallo, A., Padoan, E., Yang, K., and Dino, G. A.: Alternative ways to supply Rare Earth Elements: extractive waste recovery., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-948, https://doi.org/10.5194/egusphere-egu24-948, 2024.

EGU24-1809 | ECS | Posters on site | GMPV6.1

The occurrence and distribution of Scandium resources in the world-class Bayan Obo REE-Nb-Fe deposit, China 

Shuangliang Liu, Mingshi Wang, Zhaoyang Gao, Xuan Liu, Hong-Rui Fan, Alan Butcher, Yann Lahaye, Radoslaw Michallik, Ester Jolis, and Sari Lukkari

Scandium (Sc) is famous as a rare-scattered element in nature but can be anomalously enriched by the carbonatite system, especially in the Bayan Obo deposit (~0.14 Mt). However, the Sc distribution of Bayan Obo deposit is rarely revealed, which hinders resource utilization and the understanding of Sc mineralization. Thus, we comprehensively analyze the occurrence and distribution characteristics of Sc resources of Bayan Obo deposit, from deposit scale to mineral scale, based on 236 samples and 13 representatives. In the deposit scale, the Sc contents are 301-2 ppm (banded/massive type ores), 273-91 ppm (vein-type ores), 77-17 ppm (ore-hosting dolomite), and 281-1 ppm (slate/schist) for different rock types, respectively. Among them, the high-Sc rocks usually occur in the vicinity of the contact zone between the H9 slate/schist and the ore-hosting dolomite, which represents the most intently fenitization area in Bayan Obo. In the rock scale, Sc is heterogeneously scattered in rock with a small volume ratio (less than 0.1‰) of extremely high-Sc domains (Sc contents >0.3 wt. %). In contrast, Sc resources are more commonly found in aegirine and Na-amphibole, ranging from hundreds to thousands of ppm, sometimes reaching several weight percent, of banded/massive type ores and vein-type ores, and in biotite and titanite of altered slate/schist, typically in dozens of ppm. Notably, in the mineral scale, three types of individual Sc minerals are first distinguished in the Bayan Obo carbonatite deposit, that is thortveitite, aegirine-jervisite solid solution, and bazzite. Their metasomatism texture and mineral associations record two Sc migration and precipitation events in this deposit. These new reports reveal that the hydrothermal process is the main controlling factor of Sc resources in the Bayan Obo carbonatite system, and provide a scientific basis for the rational and effective utilization of Sc resources in this deposit.

How to cite: Liu, S., Wang, M., Gao, Z., Liu, X., Fan, H.-R., Butcher, A., Lahaye, Y., Michallik, R., Jolis, E., and Lukkari, S.: The occurrence and distribution of Scandium resources in the world-class Bayan Obo REE-Nb-Fe deposit, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1809, https://doi.org/10.5194/egusphere-egu24-1809, 2024.

EGU24-6141 | Posters on site | GMPV6.1

Sustainable restoration mortars in a circular economy perspective 

Susanna Mancini, Francesca Gambino, Antonio Tazzini, and Giovanna Antonella Dino

The present research focuses on one of the most complex and challenging applications of 'sustainable' mortar use in restoration. The study stems from the context of the PNRR NODES project – Spoke 2, coordinated by the University of Turin and promotes sustainable development and technologies for a “greener” future.

In modern construction, the use of mortars demands a finished product that is suitable for its use, with good aesthetic properties and durability over time. These characteristics are even more crucial in a restoration project, where compatibility with the old material comes into play. The sustainability of 'raw' materials, in this case secondary raw materials, is an issue that characterises the current historical moment. In this context, the characterisation of ancient mortars plays a fundamental role in establishing correlations with their sources and for the creation of new formulations.

The sustainability of 'alternative' mortars refers to the valorisation of local products, the use of waste materials and fully recyclable compounds, and reduced impact on human health and the environment. One of the potential compounds to use for mortar production can be collected from extractive waste associated to marble and limestone exploitation. Indeed, lime is alkaline and non-toxic, well-known as antiseptic and disinfectant. In addition, due to the low burning temperature and partial reabsorption of carbon dioxide during setting, lime, especially quicklime, is characterised by lower permanent CO2 emissions.

In this study different protocols are carried out, compared, and analysed in detail, with the aim of systematising 'alternative' restoration mortar formulations. These are based on the use of 'geomaterials', like waste from mining industry and construction and demolition. In particular, the lime-based binder is obtained from the calcination of white marble waste (quarry sludge, sawdust, etc.) from two different quarries located in Tuscany and Val d'Aosta. The aggregate used for the skeleton of the mortars can be obtained from quarry waste in Piedmont and Val d'Aosta (e.g. gneisses, granites, marbles, limestone, etc.) and/or concrete selected from treatment plants that recycle construction and demolition waste.

Finally, each formulation is evaluated regarding performance, compatibility with historic mortars and potential contribution to the circular economy.

The results of this research activity are an example of a multidisciplinary approach to the conservation and sustainable management of cultural heritage sites, where issues of scientific research, art, green building and circular economy are intertwined.

How to cite: Mancini, S., Gambino, F., Tazzini, A., and Dino, G. A.: Sustainable restoration mortars in a circular economy perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6141, https://doi.org/10.5194/egusphere-egu24-6141, 2024.

EGU24-6851 | Posters virtual | GMPV6.1

Critical metals distribution in Bauxite Residues: a Compositional Data Analysis approach 

Ouafi Ameur-Zaimeche, Rabah Kechiched, Paola Mameli, Ernesto Mesto, Giovanni Mongelli, Abdelhamid Oulad mansour, and Emanuela Schingaro

This research explores the major element control on the distribution of critical metals (CM) in red muds (RM), the residues of the Bayer process developed on bauxite ore, sampled at the Porto Vesme disposal site, Sardinia, Italy. RM represent an environmental challenge due to their high alkalinity and storage issues. The relationships between major elements and CM were assessed by Compositional Data Analysis (CoDa).

X-ray powder diffraction (XRPD) revealed predominant minerals including hematite, gibbsite, boehmite, anatase, cancrinite, sodalite, and quartz, consistent with previous studies on RM from the same site (Castaldi et al., 2008; Mombelli et al., 2019). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) assessment reported the major oxides composition (wt %): SiO2 (11.9 – 22.6), Al2O3 (17.4 – 24.9), Fe2O3 (22.2 – 30.3), MgO (0.7 – 4.7), CaO (2.6 – 5.9), Na2O (3.5 – 11.5), K2O (0.2 – 0.7). Iron content averaged at 25.8 wt%, underscoring i considerable presence of iron in bauxite residues, while alumina averaged at 20.75 wt% is consistent with the large amount of Al-hydroxides detected by XRPD. Among CM, specifically the LREE, the Ce abundance (93 – 258 ppm) is a notable feature.

CoDa involved Principal Component Analysis after a transformation of raw data into centred log ratio. The PC1 and PC2 association revealed significant influence from TiO2 and Na2O on critical metals such as HREE, LREE, Sc, and Co. Noteworthy is the Bayer process involving high-temperature pressure leaching of bauxite ores with sodium hydroxide solution for the Al recovery, leaving TiO2 in the resulting residue. Other CM, such as V and Ga, are predominantly controlled by MgO.

This preliminary study suggests that RM could be a promising geo-material for a strategic CM recovery and efficiently reusing the secondary byproduct, providing a sustainable and environmentally friendly alternative to its mere disposal (Liu and Naidu, 2014).

How to cite: Ameur-Zaimeche, O., Kechiched, R., Mameli, P., Mesto, E., Mongelli, G., Oulad mansour, A., and Schingaro, E.: Critical metals distribution in Bauxite Residues: a Compositional Data Analysis approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6851, https://doi.org/10.5194/egusphere-egu24-6851, 2024.

EGU24-7191 | ECS | Orals | GMPV6.1

Rare earth elements and yttrium in Oligocene coals of Makum coalfield, Assam (North-east India) 

Shivam Sharma, Debabrata Das, Prakash Tiwari, and Ramkrishna Mondal

Rare earth elements and yttrium have attracted considerable attention in recent decade due to their crucial roles in modern technology, particularly in the production of electronics, magnets, and batteries. These elements are of particular importance for developed and developing countries, as they play a significant role in clean energy as well as their growth and development. The concentration, distribution, and modes of occurrence of rare earth elements and yttrium in coal from the Oligocene formation in the Makum coalfield were investigated in this study. The study found that the coal samples from the Makum coalfield have a low ash and high sulfur content. Furthermore, the study revealed that the total concentration of rare earth elements and yttrium in the coal samples ranged from 1.48 to 77.61 ppm, with an average of 27.49 ppm. Based on the analysis of the coal samples. Average concentration of rare earth elements and yttrium in the Makum coalfield, as observed in this study, is lower than the concentration found in world average coals. it was observed that the 60ft coal seam had a higher average LREE/HREE ratio compared to the 20ft and 8ft coal seams. This indicates variations in the distribution patterns of rare earth elements and yttrium within the different coal seams. Coals from this region show a positive europium anomaly and have a weak negative cerium anomaly, indicating a significant marine influence during their formation. The sequential leaching used in this study provided valuable insights into the modes of occurrence of rare earth elements and yttrium in the coal samples from the Makum coalfield. Having a comprehensive understanding of the proportions of rare earth elements and yttrium in different forms, such as organic, silicate-aluminate, acid soluble, ion-exchangeable, and water soluble, is crucial for the development of effective methods and technologies for the extraction of these critical elements from coal.

How to cite: Sharma, S., Das, D., Tiwari, P., and Mondal, R.: Rare earth elements and yttrium in Oligocene coals of Makum coalfield, Assam (North-east India), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7191, https://doi.org/10.5194/egusphere-egu24-7191, 2024.

EGU24-7319 | ECS | Orals | GMPV6.1

LA-ICP-MS imaging technique application on Estonian sedimentary phosphorites: Revealing REE enrichment stages and advanced ore characterisation 

Sophie Graul, Vincent Monchal, Rémi Rateau, Lauri Joosu, Marko Moilanen, Mawo Ndiaye, and Rutt Hints

The importance of rare earth elements (REEs) in high-tech industries and the growing demand for raw materials have spurred interest in exploring unconventional deposits. Sedimentary phosphorite deposits are among the most prospective, with REE extraction as a P by-product. However, these ores are highly diverse regarding ΣREE content, distribution, and nature of phosphatic materials. This study focuses on the Estonian phosphorites of the Baltic paleobasin, which constitute one of Europe's largest phosphate rock reserves and are characterised by phosphatic shell fragments deposited in nearshore settings.

Geochemical investigations were conducted on carbonate-cemented phosphorites from Toolse and Aseri deposits. The determination of REE distribution and uptake mechanisms within apatites and carbonates was addressed by LA-ICP-MS in situ imaging technique developed by Drost et al. (2018), which allows identification and discrimination of mineral phases by integrating semiquantitative compositional data through the stepwise elemental distribution. Diagenetic enrichment stages were assessed using the following pathfinder elements as pooling channels: Sr and U.

Shelly apatites have homogenous REE-distribution patterns, MREE-enriched up to 15-fold compared to the PAAS, with positive Y and Ce anomalies indicative of an early digenetic overprint traceable by the Sr distribution. The average REE content in studied apatite is 2149ppm. However, the extent of diagenetic overprint and enrichment varies locally. In Toolse, shells show lesser recrystallised textures, and the Sr- and U-depleted stages allow the tracing of pristine signals prior to deposition. In Aseri, U-sorting reveals a second, alteration-driven enrichment in which fragment edges present a ΣREE up to 7020ppm. This alteration stage is less pronounced in Toolse, where REE content reaches only 4150ppm. The distinction between Sr and U-driven enrichment is less evident due to the lower input of hydrogenic or lithogenic REE carriers. The carbonates from both localities were found to be REE depleted compared to PAAS.

Based on these observations, the compositions of the apatite species could be distinguished and modelled to characterise the deposit. The diagenetic enrichment of REE was mainly driven by the upwelling of nutrient-rich waters, Fe and Mn-(oxyhydr)oxide reductive desorption, and secondary phosphatisation and homogenisation of shells. Fluctuations of redox gradients and Fe-Mn cycles led to slight local REE variability. Developing euxinic conditions and lithogenic input endorsed a later alteration-driven uptake, resulting in highly REE-rich edges. Despite differences in enrichment level, the two deposits' REE distribution patterns are similar. Main REEs are Ce (33%), Y (21%), La (12%), Nd (16%) and Dy (3%), and are considered among the most critical elements. On average, U concentrations are 92ppm in Aseri and 31ppm in Toolse, and toxic elements (Cd, Zn, Th) are found in trace amounts.

The study introduces a combined technique based on LA-ICP-MS and empirical distribution function data analyses as a powerful, accurate, cost-effective tool for determining REE distributions. It allows visualisation at different scales, representative measurements and a first approach to semi-quantifying elements. The method could provide insights into factors that control genesis in low-grade sedimentary ores and determine their potential valorisation routes.

How to cite: Graul, S., Monchal, V., Rateau, R., Joosu, L., Moilanen, M., Ndiaye, M., and Hints, R.: LA-ICP-MS imaging technique application on Estonian sedimentary phosphorites: Revealing REE enrichment stages and advanced ore characterisation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7319, https://doi.org/10.5194/egusphere-egu24-7319, 2024.

The Sardinia region has a longstanding tradition in ornamental granite extraction, reaching its production peak in the 1990s when it became Italy's leading granite producer, accounting for 90% of the national production [1]. However, the industry faced a decline starting from the mid-2000s due to the entry of other competitors into the global market and due to significant infrastructure issues on the island [1]. The 2008 financial crisis further reduced global granite demand and in the subsequent years, compounded by the events of the COVID-19 pandemic, prolonged the crisis in the sector. In Italy, granite production plummeted from over 2 million metric tons in 2011 to just under 200,000 metric tons in 2022 [2].
Granite extraction has a striking impact on the Sardinian landscape, with landfills of granite blocks, visible from kilometers away, contributing to significant landscape degradation. These, in addition, affect plans to develop the unique archaeological sites of the Domus de Janas and contribute to soil depletion. 
The European Critical Raw Materials Act to future supply chains is crucial for Europe's green and digital transition, in line with the European Green Deal that identified recycling as part of the supply solution. In this context, recognizing potential opportunities for recycling these waste materials could aid in advancing the objectives of the European Union, enhance the aesthetic quality of the Sardinian landscape, and contribute to revitalize the granite extraction industry in Sardinia.
This study focuses on the circular economy in a granite quarry located in the municipality of Buddusò (province of Sassari, Sardinia). Active for about 40 years, this quarry has accumulated significant amounts of granite waste from which feldspar, quartz and rare earth elements can be extracted. This research presents the results of geochemical, petrographic, and mineralogical analyses conducted on granite waste samples from the quarry under study. In addition, potential recycling solutions for this material in the context of Critical Raw Material supply are discussed.

References:

[1] Careddu, N.; Siotto, G.; Marras, G. The Crisis of Granite and the Success of Marble: Errors and Market Strategies. The Sardinian Case. Resources Policy 2017, 52, 273–276. https://doi.org/10.1016/j.resourpol.2017.03.010.
[2] Istituto Nazionale di Statistica - Istat. Production in Value and Quantity per Single Product - Granite and Similar Rocks, Rough, without Shape. Accessed 18/12/2023. https://esploradati.istat.it/databrowser/#/it/dw/categories/IT1,Z0600IND,1.0/IND_PRODUCTION/DCSP_PRODCOM/IT1,115_168_DF_DCSP_PRODCOM_2,1.0

How to cite: Aquilano, A., Marrocchino, E., and Vaccaro, C.: Granite waste produced in quarries exploitation in northern Sardinia (Italy): recycling chances within the context of Critical Raw Material supply, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8434, https://doi.org/10.5194/egusphere-egu24-8434, 2024.

SEM-EDS and polarized optical microscopy analysis of granite blocks taken from decorative rocks quarry waste landfills in Sardinia were used in mining prospecting to evaluate potential unconventional sources of critical raw materials (CRMs). Achieving the goals outlined in the European Green Deal regarding the green and digital transition may face significant challenges due to the substantial increase in demand for CRMs in the near future so access to CRMs is a strategic security issue for the European Union.

Because of the similar chemical properties that characterize Rare Earth group elements among themselves, there are few effectively exploitable deposits in the world. Predominantly in carbonatite complexes and pegmatitic granitoid bodies, the subtle variations in the properties of RE (Rare Earth) group elements allow significant fractionation and economically exploitable enrichment of small intrusive bodies and/or intrusive veins consisting of one or more REE minerals, such as allanite, REE oxides, apatites, and carbonates.

Sardinia's ornamental granite quarries have in the past generated high concentrations of unmarketable waste (mostly pegmatite bodies and veins with REE-enriched late-magmatic and deuteric mineralogical phases). The huge amount of these waste accumulations has resulted in high land consumption and landscape distortions, but with the increased REE demand they now represent an important resource, as they can contribute to the implementation of the EU Critical Raw Materials Act.

This study reports the results of SEM-EDS investigations combined with polarized optical microscope observations conducted on thin sections of granite obtained from waste samples from the numerous leucogranite quarries of Buddusò (Northern Sardinia, Italy). These granites are composed primarily of quartz, plagioclase, K-feldspar, and biotite, with accessory minerals including zircon, epidote, titanite, ilmenite, apatite, and xenotime. Feldspars have recently been included in the list of Critical Raw Materials[2]; therefore, the identification of solutions for their exploitation (which represent a significant portion of the rocks investigated) could provide a strong contribution to the needs of the European Union. Epidotes often appear in these rocks as allanite enriched in light rare earth elements.

In this context, it could be very interesting to evaluate the possibility of applying physical mineral separation methodologies to obtain, on the one hand, mineral concentrates containing Rare Earth Elements for the extractive metallurgy industry. On the other hand, feldspars have recently been included in the list of Critical Raw Materials [1]; therefore, identifying solutions for their exploitation (which represent a significant portion of the investigated rocks) could provide a strong contribution to the needs of the European Union.

This study of the quartz and feldspar phases and REE concentrations in accessory minerals will be useful in optimizing the physical separation methodologies of minerals useful to obtain CRMs for industry and the ceramic and glass manufacturing sectors.

Reference:

[1] Grohol, M., C. Veeh, DG GROW, e European Commission. «Study on the Critical Raw Materials for the Europe - Final Report». Luxembourg: European Union, 2023.

How to cite: Vaccaro, C., Aquilano, A., and Marrocchino, E.: SEM-EDS and Polarized Optical Microscope Analysis of Granite Quarry Waste to Reveal Potential Unconventional Sources of Critical Raw Materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8511, https://doi.org/10.5194/egusphere-egu24-8511, 2024.

EGU24-16645 | Posters on site | GMPV6.1

Geochemical tracing of Nd magnets – a possible future tool to improve sustainable sourcing of critical raw materials? 

Jakob K. Keiding, Nolwenn Coint, Benjamin Heredia, Nynke Keulen, Yann Lahaye, and Xuan Liu

Raw material supply chains are intricate and complex systems that often suffer from a lack of transparency. To enhance sustainability in mineral supply, there is an urgent need to rectify this transparency deficit. Traceability, which involves tracking a product through different stages of production, transformation, and commercialization, from its origin to its end-of-life, including potential recycling, could be a crucial facilitator for increased transparency.

Nd magnets (also known as NdFeB magnet) are the strongest permanent magnet type known and serve as critical components in green technologies like windmill turbines and electric motors for vehicles. While Nd magnets offer numerous advantages, their production involves the use of rare earth elements (REE), critical raw materials that lack supply chain transparency, standards, and certification schemes regarding environmental and social impacts, and governance. The objective of this study is to investigate whether there are distinct chemical characteristics associated with Nd magnets and to determine the feasibility of establishing a correlation between a magnet and unidentified information, potentially linking it to a plausible source.

Nd magnets have been systematically collected for the purpose of tracing their material origins. Two distinct categories of Nd magnets were assessed for this investigation. The first category comprises novel magnets with documented production years (ranging from 1999 to 2023) and varying grades marked by different Nd contents. The second category consists of magnet scraps lacking specific information. Our study employed a comprehensive approach, incorporating automated quantitative mineralogy (AQM), Scanning Electron Microscope spectroscopy element mapping (SEM-EDS) to examine microtextures and major element content, and LA-ICP-MS analyses for trace elements and Nd isotopes.

Analyzing these magnets revealed noticeable compositional distinctions among samples, both in terms of manufacturing sources and production years. Four distinct groups of trace elements were identified in the novel magnets, aiding in the differentiation of various production year groups. These groups include Ti, Cr, Se, La, Cr, Nd, Gd, Yb (Group 1), B, Eu, Tb (Group 2), Al, As, Ge, Pr, Sm, Dy, Tm (Group 3), and Mn, Ho (Group 4). Nd isotope analyses indicated a broad present-day epsilon Nd values, ranging from -30 to -7, with some degree of inter-sample overlaps. This extensive range appears to surpass the typical coverage of REE deposits. Higher values suggest the potential incorporation of REEs from South China ion-absorption deposits, while lower values hint at the involvement of REEs from Olympic Dam (Australia) and/or Mountain Pass (US).

These preliminary findings contribute with valuable insights into the diverse origins and compositions of Nd magnets, suggesting that geochemical fingerprinting could emerge as a pivotal traceability tool for assessing the origin of Nd magnets in the future.

How to cite: Keiding, J. K., Coint, N., Heredia, B., Keulen, N., Lahaye, Y., and Liu, X.: Geochemical tracing of Nd magnets – a possible future tool to improve sustainable sourcing of critical raw materials?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16645, https://doi.org/10.5194/egusphere-egu24-16645, 2024.

EGU24-16673 | ECS | Orals | GMPV6.1

Use of Interferometric Synthetic Aperture Radar Techniques as a remote tool for Mineral Extraction Sites Monitoring  

Francesco Falabella, Antonio Pepe, Krištof Oštir, and Fabiana Calò

This work addresses the preliminary achievements of the Horizon Europe European project S34I1 (Secure and Sustainable Supply of Raw Materials for EU Industry) (https://s34i.eu) that aims to increase the autonomy of Europe over raw materials resources through research and development of new data-driven methods devoted to the analysis of Earth observation data.

Among the different activities of the project, one of the major contributions is related to the systematic monitoring of mining site instabilities by developing and applying advanced multi- temporal interferometric SAR (InSAR) techniques for the generation of long-term deformation time series. To this purpose, an InSAR multi-grid technique for efficient processing of sequences of differential SAR interferograms (particularly, phase unwrapping operations) has been carried out directly at the native high-resolution spatial grid without any model or assumption on deformation.

Experiments were carried out at the Gummern, Austria, extraction site by processing two sets of ascending and descending SAR datasets collected by the EU Copernicus Sentinel-1A/B sensors from October 2014 to March 2023. The line-of-sight (LOS)-projected ground displacement time series were generated by inverting the unwrapped single-look interferograms using the Small BAseline Subset (SBAS) algorithm. Consequently, non-linear and seasonal patterns that could indicate a sudden failure of the surface can be identified with millimetre precision. A post-operation step was also performed over the group of georeferenced common targets as seen from complementary geometries (i.e., ascending and descending orbits) to compute from LOS-projected ground deformations the long-term 2-D (up-down, east-west) ground displacement time series. To this aim, conventional and new combination methods are applied by assuming the north-south displacements do not significantly contribute to the observed LOS measurements.

1This study is funded by the European Union under grant agreement no. 101091616, project S34I – SECURE AND SUSTAINABLE SUPPLY OF RAW MATERIALS FOR EU INDUSTRY, coordinated by Ana C. Teodoro.

How to cite: Falabella, F., Pepe, A., Oštir, K., and Calò, F.: Use of Interferometric Synthetic Aperture Radar Techniques as a remote tool for Mineral Extraction Sites Monitoring , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16673, https://doi.org/10.5194/egusphere-egu24-16673, 2024.

EGU24-17463 | ECS | Orals | GMPV6.1

Stirred-tank reactor bioleaching of nickel and cobalt from Brazilian laterite ores 

Stefanie Hetz and Axel Schippers

Laterite ore deposits in Brazil and other tropical countries harbor large amounts of nickel and cobalt resources, along with other critical raw materials. The conventional methods of recovering nickel and cobalt, such as pyrometallurgy or high-pressure acid leaching, entail high energy, reagent costs, and expensive equipment. To address this, the German-Brazilian project BioProLat aims to develop an integrated, low-energy, and environmentally friendly biohydrometallurgical process for metal recovery from Brazilian laterite ores.

The process involves leveraging acidophilic bacteria that use sulfur as an electron donor, coupling sulfur oxidation to the reduction of ferric iron, ultimately converting insoluble metal compounds into water-soluble forms. This generates sulfuric acid, creating the necessary acidic conditions to keep iron and other metals soluble. Laboratory-scale bioreactor experiments optimized parameters like pH, temperature, and a suitable bacterial consortium for bioleaching nickel and cobalt. Results from aerobic bioleaching of laterite with a consortium of Acidithiobacillus thiooxidans strains showed an extraction of 85% for both cobalt and nickel. Mineralogical and geochemical analyses were conducted to identify mineral phases, which are attacked by bioleaching, and estimate the portions of cobalt and nickel released by bioleaching of different mineral phases. The goal is to scale up the optimized process, converting untapped ores and limonite stockpiles into valuable resources and unlocking new raw material reserves by enhancing metal recovery from existing mines.

How to cite: Hetz, S. and Schippers, A.: Stirred-tank reactor bioleaching of nickel and cobalt from Brazilian laterite ores, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17463, https://doi.org/10.5194/egusphere-egu24-17463, 2024.

EGU24-19639 | Orals | GMPV6.1 | Highlight

Quarry dust an essential component in the pyrometallurgical recovery of valuable materials from mixed fine-grained waste 

Axel D. Renno, MD Naziat Hossain, Anna Magdalena Baecke, Abrar Kabir, and Stefan Dirlich

Within the FINEST project (https://finest-project.de/) we tackle the use and management of finest particulate anthropogenic material flows in a sustainable circular economy. Subproject 3 "FINEST Disperse Metals" has set itself the goal of safely mixing various fine and ultra-fine-grained material flows that accumulate as waste during various industrial processes and extracting metallic raw materials from them in a subsequent multi-stage pyrometallurgical process, as well as generating a safe slag that can be disposed of without monitoring.

The idea of mixing different fine-grained waste streams arose from the experience that the search for economically and ecologically sustainable forms of recycling for the individual types of waste often failed despite promising approaches. This is usually due to individual parameters of the chemical or phase composition. The mixing we are aiming for allows us to select the technological parameters much more freely and to react to the rapid changes that are typical of waste streams.

We will implement this concept using three different material streams:

  • So-called shredder fines from plastics, car and WEEE recycling
  • Metallurgical fly ash from non-ferrous metallurgy
  • Quarry dust and dust from concrete recycling.

 

The experimental work is preceded by a comprehensive characterization of the material flows in terms of chemical and phase composition, general physical parameters such as particle size distribution, particle shapes and flowability as well as any potential hazards. Based on this, both the mixing behavior and the pyrometallurgical parameters are modeled.

We use quarry dust for two main purposes. Their main contribution is to act as slag formers in the pyrometallurgical processing of the mixtures in the plasma furnace. This should be combined with the lowest possible liquidus temperatures and viscosities of the slag system. We are currently using four different quarry dusts from active quarries in the Free State of Saxony for our investigations (1 granite, 2 granodiorites and 1 amphibolite) as well as material from the concrete recycling of an extensive demolition project in Dresden.

Optimized mixing ratios between the individual quarry dusts and various metallurgical flue dusts were determined as part of the modeling using FactSageTM.  The behavior during mixing of the material flows was initially investigated theoretically using model materials. The mixing steps were visualized using X-ray computed tomography.

How to cite: Renno, A. D., Hossain, M. N., Baecke, A. M., Kabir, A., and Dirlich, S.: Quarry dust an essential component in the pyrometallurgical recovery of valuable materials from mixed fine-grained waste, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19639, https://doi.org/10.5194/egusphere-egu24-19639, 2024.

EGU24-21695 | ECS | Orals | GMPV6.1 | Highlight

Recovery of Metals from Municipal Solid Waste Incineration Plants Wastes: A Comparative Case Study of Pre- and Post-Pandemic Periods 

Junaid Ghani, Katerina Rodiouchkina, Ilia Rodushkin, Enrico Dinelli, Valerio Funari, Thomas Aiglsperger, Lena Alakangas, and Emma Engström

Municipal Solid Waste Incineration (MSWI) plants are of great concern, generating solid by-products, namely Fly Ash (FA) and Bottom Ash (BA). These MSWI residues have received significant attention for environmental concerns and the recovery of valuable elements, minerals, and secondary raw materials. The potential recovery of elements in MSW are crucial for circular economy and environmental sustainability (Han et al, 2021; Funari et al, 2016). Therefore, available types of fly ashes samples, i.e., lime- and soda-doped fly ash from bag filters following electrostatic precipitation, and quenched BA samples were sampled during pre- (2013, 2020) and post-pandemic period (2021, 2022) from two grate-furnace MSWI plants, located in Ferrara (FE) and Forlì (FC) cities in Italy. The sample preparation and elemental analysis were performed at ALS Scandinavia laboratory as a part of an international research collaboration between University of Bologna, Luleå University of Technology, and ALS Scandinavia. In this study, we aimed to determine and compare the elemental composition in MSWI samples by Inductively Coupled Plasma-Sector Field Mass Spectrometry (ICP-SFMS) to assess metal abundance by enrichment factor and elemental flows using substance flow analysis and MSWI systems’ mass balance (Brunner and Rechemberg, 2004). Our results showed that recovery of valuable elements (Al, Fe, Si, Zn, and Cu) was high after strong digestion method for all the FA and BA samples. Overall, little variation in elemental composition of FA and BA in both selected periods (pre-pandemic vs post-pandemic) suggests a similar input flow of urban waste. Enrichment factors (EF) show enrichment of Zn, Cu, Al, Fe, Mg, Ca, Na, K, and potentially toxic elements like Pb, Cd in both FA and BA. The chondrite normalized REE patterns of FA and BA are relatively similar suggesting that the BA and FA feeding material are mostly geogenic materials, with possible anthropogenic fluctuation for Ce, Tb, and Yb. The upper continental crust (UCC) normalization patterns were consistent for most elements. In contrast, Ba, K, P, and La patterns vary, likely showing an anthropogenic signal. Mass balance assessment showed that the waste streams can host from low to high concentration of strategic elements as an alternative source of value in the circular economy.

 

References

  • Funari, V., Bokhari, S.N.H., Vigliotti, L., Meisel, T. and Braga, R., 2016. The rare earth elements in municipal solid waste incinerators ash and promising tools for their prospecting. Journal of Hazardous materials, 301, pp.471-479.
  • Han, S., Ju, T., Meng, Y., Du, Y., Xiang, H., Aihemaiti, A. and Jiang, J., 2021. Evaluation of various microwave-assisted acid digestion procedures for the determination of major and heavy metal elements in municipal solid waste incineration fly ash. Journal of Cleaner Production, 321, p.128922.
  • Brunner, P.H., Rechberger, H., 2004. Methodology of MFA. In: Practical Handbook of Material Flow Analysis. Lewis Publishers, Boca Raton London New York Washington, D.C., pp. 34–166, ISBN: 1-5667-0604-1.

How to cite: Ghani, J., Rodiouchkina, K., Rodushkin, I., Dinelli, E., Funari, V., Aiglsperger, T., Alakangas, L., and Engström, E.: Recovery of Metals from Municipal Solid Waste Incineration Plants Wastes: A Comparative Case Study of Pre- and Post-Pandemic Periods, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21695, https://doi.org/10.5194/egusphere-egu24-21695, 2024.

ERE5 – Process coupling and monitoring

EGU24-468 | ECS | Posters on site | ERE5.1

Injection Rate effects on failure of a saturated gouge-filled fault failure: Dilation vs. Diffusion 

Pritom Sarma, Einat Aharonov, Renaud Toussaint, and Stanislav Parez

Understanding the underlying mechanisms controlling earthquake triggering by fluids has become increasingly important in recent decades, driven largely by observations that link subsurface fluid injections to subsequent nearby earthquakes. It is clear that understanding and predicting fluid-induced triggering is required in many energy-related activities (e.g. geothermal energy, CO2 injection), as well as for naturally triggered events. One of the main open questions is the effect of fluid-injection rate. Usually the ‘effective stress law’ is invoked to predict the failure of fluid-saturated granular or porous media. This law assumes that in fluid-pressurized faults the instantaneous value of pore pressure controls fault strength and failure. But recent laboratory results (Passelègue et. al., 2018) suggest that the level of pressure by itself cannot describe the full mechanics. These experiments show that the rate of fluid injection is also important: slower injections lead to failure at lower pressures than fast injection rates. 

 

We shall present results from a coupled hydromechanical-discrete element model that simulates the response of a pre-stressed, fully saturated fault, filled with a granular fault gouge, subject to fluid injection at different rates. Our simulation results find similar rate-dependence as seen in the laboratory experiment, i.e. that slow injection causes failure at lower fluid pressure than faster injection. Several mechanisms can be theorized to explain these observations, and we explore the two main end-member cases, dilation-driven and diffusion-driven rate-dependence, by comparing theoretical predictions for the poro-elastic response of the layer vs. pore-pressure diffusion. Our theoretical analysis provides upper and lower bounds to the numerically observed  rate dependence, suggesting the reason why the effective stress law is an insufficient approximation for failure of material exposed to pore fluid injection, when the pore-pressure injection rate is varied.

How to cite: Sarma, P., Aharonov, E., Toussaint, R., and Parez, S.: Injection Rate effects on failure of a saturated gouge-filled fault failure: Dilation vs. Diffusion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-468, https://doi.org/10.5194/egusphere-egu24-468, 2024.

EGU24-3259 | Orals | ERE5.1

Predicting observed induced seismicity due to production in the Hverahlid, SW Iceland, geothermal field 

Vala Hjörleifsdóttir, Kristín Jónsdóttir, Halldór Geirsson, Ásdís Benediktsdóttir, and Sigríður Kristjánsdóttir

The Hverahlíð geothermal field, located in the fissure swarm of Hengill volcano, SW Iceland, has been producing steam and geothermal fluids for the Hellisheiði geothermal power plant (303 MWe, 210 MWth), since late 2016.  A total of 7 geothermal wells in the field (HE-21, -26, -53, -54, -60, -61 and -66) have been producing up to 150 kg/s of steam and 60-70 kg/s of separated liquid.  The combined extraction from the wells is limited by the size of the steam pipeline connecting the field to the power plant.  

Within months of the initiation of production an increase in seismicity was noted within the field.  This is in contrast to the nearby Hellisheiði geothermal field, ~2 km away, which has experienced very little induced seismicity since commission in 2006, despite more than twice as high mass extraction rates and higher deformation rates.  Since early 2018 a total of 8 events with M> 2.5 have occurred in the field.  The latest of these events occurred in November 2022 with M 3.2. The seismicity largely does not line up on faults and is relatively evenly distributed throughout what is considered the top of the geothermal reservoir (Kristjánsdóttir et al 2019).

Currently a second pipeline connecting the geothermal field with the power plant is in construction and with the commission, planned for fall 2024, an increase in mass extraction rates from the Hverahlíð geothermal field  of ~30% is expected.

In this presentation we compare the observed location, seismicity rates and Mmax values to those expected from different models of earthquake triggering.  We furthermore predict the expected increase in seismicity rates due to the increase in production rates and the increase in seismicity that will be felt by the neighboring community of Hveragerði.

How to cite: Hjörleifsdóttir, V., Jónsdóttir, K., Geirsson, H., Benediktsdóttir, Á., and Kristjánsdóttir, S.: Predicting observed induced seismicity due to production in the Hverahlid, SW Iceland, geothermal field, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3259, https://doi.org/10.5194/egusphere-egu24-3259, 2024.

EGU24-3789 | Posters on site | ERE5.1

Characteristics for b-value of induced seismicity in Southeast of Sichuan Basin, China 

Mengyu Xie, Yunxiao Zhao, and Lingyuan Meng

Due to abundant shale gas buried beneath Southeast of Sichuan Basin, China (SBC), hydraulic fracturing operations are implemented since 2008. And large-scale shale gas mining began in December 2014. A rapid increase in the rate of seismicity in SBC since 2015, including the 16 December 2018 MS5.7, the 3 January 2019 MS5.3, the 17 June 2019 MS6.0, the 8 September 2019 MS5.4, the 18 December 2019 MS5.2, the 16 September 2021 MS6.0 and the 6 April 2022 MS5.1 earthquakes. Those earthquakes have caused much damages and many injures, which attracts a lot of attention from society and researchers. The related studies show that seismicity in SBC are induced by or related to hydraulic fracturing operation (Meng et al, 2019; Lei et al, 2019). In this work, we try to study the characteristics of local seismicity and explore the spatiotemporal characteristics of b-value in G-R relation to gain insight into the possible dynamic processes beneath the induced seismicity and assess the seismic hazards. The preliminary results indicate that the average b-value decrease from 1.17 to 0.75 when the 16 September 2021 MS6.0 earthquake occurred. And there is a substantial reduction of b-value before the 8 September 2019 MS5.4 earthquake. Moreover, the temporal variations for b-values don’t show a common pattern.

 

This study was supported by the Science for Earthquake Resilience (XH22011YA), “Real-time analyze characteristics of earthquake sequence by b-value and waveform” and National Natural Science Foundation of China (41974068), “Seismicity for Shale Gas Hydraulic Fracturing Stimulation”.

 

Lei X L, Wang Z W, Su J R. 2019. The December 2018 ML 5.7 and January 2019 ML 5.3 Earthquakes in South Sichuan Basin Induced by Shale Gas Hydraulic Fracturing. Seismological Research Letters, 90(3), 1099-1110, doi: 10.1785/0220190029.

Meng L, McGarr A, Zhou L, Zang Y. 2019. An Investigation of Seismicity Induced by Hydraulic Fracturing in the Sichuan Basin of China Based on Data from a Temporary Seismic Network. Bulletin of the Seismological Society of America, 109(1), 348–357, doi: 10.1785/0120180310.

How to cite: Xie, M., Zhao, Y., and Meng, L.: Characteristics for b-value of induced seismicity in Southeast of Sichuan Basin, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3789, https://doi.org/10.5194/egusphere-egu24-3789, 2024.

EGU24-5646 | ECS | Posters on site | ERE5.1

On the triggering mechanism of fault-slip bursts during deep underground excavation 

Wenbo Pan, Zixin Zhang, Shuaifeng Wang, Chenxi Zhao, and Qinghua Lei

To meet the target of net-zero emissions by 2050, six times more mineral inputs are required in 2040 than today. However, with the depletion of mineral resources in the shallow subsurface, mining at great depth is inevitable. Furthermore, the rapid development of urban systems, transport networks, and hydropower plants also impose an increased demand of deep underground excavation. These deep mining or tunneling activities are, however, confronted with the risk of induced earthquakes and rockbursts. For example, during the Gotthard Base Tunnel construction at great depths of up to 2.5 km in the Swiss Alps, extensive regional earthquakes with magnitudes reaching up to Mw 2.4 were recorded. Accompanying some of these earthquake events, intense rockbursts occurred at the Faido Multifunction Station. So far, it remains poorly understood the triggering mechanisms of these rockburst events and their relationship with the induced earthquakes. Here, we develop a novel three-dimensional coupled seimo-mechanical model which can capture the rupture of a seismogenic fault zone, the redistribution of stress field, the propagation of seismic waves, and the occurrence of coseismic rockbursts in a tunnel located a few hundred meters away from the hypocenter (i.e., in the near-field of the earthquake fault). We investigate the competing roles of static and dynamic triggering in generating these fault-slip burst events and find that static stress changes play a much more dominant role than dynamic waves. The results and insights derived from our research have important implications for understanding and predicting catastrophic rockbursts during deep underground excavation for various geoenergy or geoengineering applications, ranging from critical mineral extraction and nuclear waste disposal to underground energy storage and civil infrastructure development.

How to cite: Pan, W., Zhang, Z., Wang, S., Zhao, C., and Lei, Q.: On the triggering mechanism of fault-slip bursts during deep underground excavation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5646, https://doi.org/10.5194/egusphere-egu24-5646, 2024.

EGU24-5696 | ECS | Orals | ERE5.1

Picoseismic response of hectometer-scale fracture systems to stimulation under the Swiss Alps, in the Bedretto Underground Laboratory 

Anne Obermann, Martina Rosskopf, Virginie Durand, Katrin Plenkers, Kai Bröker, and Nima Gholizadeh Doonechaly

We performed a series of hydraulic stimulations at 1.1 km depth in the Bedretto underground laboratory in the Swiss Alps. The goal was to achieve an unprecedented detailed and profound understanding of hydromechanical and seismic processes during hydraulic reservoir development with a dense multi-sensor monitoring network. With our seismic network that includes various sensor types with different sensitivities, we succeeded in characterizing induced seismicity down to the pico-seismicity level (Mw<-4), thus illuminating details of a complex fracture network more than 100 m from the injection locations. Here, we present the experiments and seismic catalogs as well as a comparative analysis of event number per injection, magnitudes, b-values, seismogenic index and reactivation pressures.

During a first-order data analysis, we could make the following observations: 

-        We find that the ultra-high frequency seismic network with custom-made AE sensors, allows us to observe seismicity over 3 orders of magnitude scale. Thanks to collocated accelerometers and acoustic emission sensors, AE sensors could be calibrated in-situ and adjusted moment magnitudes could be implemented into the seismic catalog. 

-        The volume impacted by the stimulations in different intervals differs significantly with a lateral extent from a few meters to more than 150 m. Most intervals activated multiple fractures. Only during the stimulation of an interval located next to a dominant shear zone, an extended single fracture was activated, which is likely attributed to the dominant shear zone in this area. The seismic clouds typically propagate upwards towards more permeable, shallow depth on parallel dipping planes that are consistent with the stress field and seem to a large extent associated with preexisting open fractures.

-        It is worth noting the strong correlation between the propagation patterns observed in the seismic events and the hydromechanical observations, specifically in terms of the strain and pressure data obtained from Distributed Strain Sensing (DSS), the Fiber Bragg Grating (FBG) and the pore pressure sensors that form part of the multi-component borehole monitoring system. 

-        This experiment confirms the diversity in seismic behavior independent of the injection protocol. Some intervals showed rapidly increasing seismicity that is spatially restricted to the volume in direct vicinity of the injection point, while others have seismicity extending as far as 150 m away from the injection point.

-        The reactivation pressures hint at hydraulic shearing as the dominant process, since the elastic fracture opening appears to be mostly aseismic.

-        The seismicity shows no distinct deviation from “normal” behavior with regard to Gutenberg Richter or McGarr. 

We have the opportunity to analyze the seismic data jointly with a multitude of other geophysical observables, such as strain and pressure, to allow more insights into the correlation of slow fracture opening and aseismic deformation processes. In future studies, the existence of these multi-disciplinary observations will allow us to put more constraints on the processes responsible for the diversity observed in seismicity.

How to cite: Obermann, A., Rosskopf, M., Durand, V., Plenkers, K., Bröker, K., and Gholizadeh Doonechaly, N.: Picoseismic response of hectometer-scale fracture systems to stimulation under the Swiss Alps, in the Bedretto Underground Laboratory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5696, https://doi.org/10.5194/egusphere-egu24-5696, 2024.

EGU24-6443 | ECS | Orals | ERE5.1

What are the alternative pumping strategies to stimulate areservoir without triggering distant faults? 

Bérénice Vallier, Renaud Toussaint, Marwan Fahs, Clément Baujard, Albert Genter, Eirik Grude Flekkøy, and Knut Jørgen Måløy

In the context of deep reservoir exploitation, it is necessary to enhance reservoir permeability before exploitation. One method to achieve this is by conducting stimulations through fluid injection, which increases pore pressure, reduces the effective normal stress and allows dilatant shear and porosity increase along small fractures in the reservoir, in the vicinity of the injection well. The pore pressure diffuses throughout the reservoir and can also sometimes reach distant faults that are critically stressed, with a risk to trigger seismicity along these. The model we propose aims to decrease the effective normal stress reduction caused by pressure disturbance along such distant faults, which can cause the rupture of critically stressed distant faults and induce seismic activity. This work investigates an alternative pumping method to stimulate a reservoir without triggering distant faults. To achieve this, a numerical model based on the finite difference method has been developed to solve the diffusion equation of pressure disturbances. The simplifying assumption is that the domain is isotropic and homogeneous. The 2D domain represents the fault plane and permeable damaged zone embedded in less permeable rock. To validate the numerical model, the numerical distant pressure disturbances are compared to analytical solutions developed from the Green's function of the diffusion equation. The numerical model investigates the impact of a time-dependent oscillating injection strategy on near-well and distant pressure disturbances, in comparison to other tested methods, to minimize induced seismicity. The results suggest that the oscillating pumping strategy has the potential to significantly reduce induced seismicity on distant faults. Future research will involve developing mitigation strategies using more complex models that incorporate realistic fault geometries and operational conditions.

How to cite: Vallier, B., Toussaint, R., Fahs, M., Baujard, C., Genter, A., Flekkøy, E. G., and Måløy, K. J.: What are the alternative pumping strategies to stimulate areservoir without triggering distant faults?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6443, https://doi.org/10.5194/egusphere-egu24-6443, 2024.

EGU24-8026 | ECS | Orals | ERE5.1

Pseudo-prospective forecasting of induced and natural seismicity in the Hengill geothermal field 

Vanille Ritz, Leila Mizrahi, Victor Clasen Repollés, Vala Hjörleifsdóttir, Antonio Pio Rinaldi, and Stefan Wiemer

The Hengill geothermal field, located in southwest Iceland, is host to the Hellisheiði power plant, with its 40+ production wells and 17 reinjection wells. Located on a tectonically active area, the field experiences both natural and induced seismicity associated to the power plant operations. To better manage the risk posed by this seismicity, the development of robust and informative forecasting models is paramount.

In this study, we compare the forecasting performance of a model developed for fluid-induced seismicity (the Seismogenic Index model) and a class of well-established statistical models (Epidemic-Type Aftershock Sequence). The pseudo-prospective experiment is set up with 14 months of initial calibration and daily forecasts for a year. In the timeframe of this experiment, a dense broadband network was in place in Hengill, allowing us to rely on a high quality relocated seismic catalogue. The seismicity in the geothermal field is characterised by four main clusters, associated with the two reinjection areas, one production area an area with surface geothermal manifestations but where no operations are taking place. We show that the models are generally well suited to forecast induced seismicity, despite some limitations, and that a hybrid ETAS  model accounting for fluid forcing has some potential in complex regions with natural and fluid-induced seismicity.

How to cite: Ritz, V., Mizrahi, L., Clasen Repollés, V., Hjörleifsdóttir, V., Rinaldi, A. P., and Wiemer, S.: Pseudo-prospective forecasting of induced and natural seismicity in the Hengill geothermal field, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8026, https://doi.org/10.5194/egusphere-egu24-8026, 2024.

EGU24-8044 | Orals | ERE5.1

Presenting a new holistic robust approach for predicting geo-failures in complex underground engineering projects 

Majid Khan, Xueqiu He, Dazhao Song, Zhenlei Li, Xianghui Tian, and Umair Khan

The exploration of geo-resources in complex geological provinces poses significant challenges, often resulting in severe geological disasters with economic losses and fatalities. Fractured rocks, pre-existing fractures, and excavation-induced fractures contribute to the complexity of these disasters. Despite numerous studies, understanding the coupling mechanism of induced seismicity and geological deformations in such complex mining environments remains unclear. This study introduces the "Acousto-Frac Model," a novel, cost-effective, and robust geophysical approach designed to comprehensively understand experimental microseismicity and reveal such a mechanism. Traditionally, physical models and numerical simulations have been employed for dynamic disaster prediction in underground coalmines. However, these methods are often neither cost-effective nor robust. The Acousto-Frac Model offers an innovative methodology for mapping induced fracture networks through Acoustic Emission (AE) experiments conducted on coal and rock samples. This approach tracks each AE event, constructs networks of induced fractures, identifies geological lineaments, and predicts zones prone to failure/disasters.

To implement the model, AE and rock mechanics testing systems were utilized to conduct experiments on coal and rock samples under uniaxial loading. The proposed model successfully identified weak zones, predicting general deformation propagation directions. Moreover, the 3D crack growth theory and the criterion for microcrack density were employed to analyze the fracture transformation process, ranging from small-scale microfractures to large-scale microfractures and from local deformation to complete damage for the coal and rock samples subjected to uniaxial loading.

The study further leverages Single Link Cluster (SLC) simulations and b-value theory to characterize the spatiotemporal response of microearthquakes, including b-value, spatial correlation length (ξ), and information entropy (H). Notably, the results indicated that at the onset of initial loading (15%), the spatial correlation length (ξ) exhibited an upward trend, while the b-value remained comparatively stable. These parameters showed a significant change trend before the buckling failure of coal and rock samples, suggesting that, in combination with the proposed model, spatial correlation length (ξ), b-value, and information entropy (H) provide a new and robust method for complete deformation evaluation and the prediction of geo-material failure. This innovative method, while a panacea for imaging the entire fracturing phenomenon, provides insights with widespread implications for academic researchers and industry practitioners. It serves as a valuable tool for predicting geological failures in global underground engineering excavations, offering a comprehensive and cost-effective solution for the mapping of induced seismicity and geological deformations in underground mines.

How to cite: Khan, M., He, X., Song, D., Li, Z., Tian, X., and Khan, U.: Presenting a new holistic robust approach for predicting geo-failures in complex underground engineering projects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8044, https://doi.org/10.5194/egusphere-egu24-8044, 2024.

A thorough understanding of geological and hydraulic fracturing aspects can offer significant insights into the physical mechanisms governing earthquakes. In this study, we conducted seismic monitoring near a hydraulic fracturing well-pad in the southern Sichuan Basin. The monitoring adopts a dense seismic array that consists of 60 three-component stations, and last for a duration of 53 days. Accordingly, we resolved and located over 1,000 events (-1.43<M<2, Mc=-0.72). Most events (~ 70%) distributed near the southwest direction of the injection wells, delineating a series of NE-SW trending structures. Our high-resolution hypocenter locations and statistical analysis reveal two distinctive clusters: (i) one linearly-distributed cluster characterized by larger magnitudes, deeper focal depths and a b value (1.09) comparable to tectonic earthquakes; (ii) one relatively scattered cluster with smaller magnitudes, shallower depths and a higher b value (1.29). We speculate that deeper events are more consistent with seismicity occurring on pre-existing fault(s), whereas shallower events occur within a fracture network.

The detailed structures are further evaluated with resolved focal mechanisms and 3D seismic reflection imaging. The deeper events unanimously support a right-lateral, steep strike-slip fault, consistent with the fault geometry depicted by high-resolution hypocenter locations. In comparison, focal mechanisms of the shallower earthquakes are more complex and diverse, showing a mixture of normal fault and strike-slip events. In the vicinity of the two clusters, seismic reflection data indicates a ~3 km-length fault that strikes in approximately north-south (NS) orientation. Therefore, we suggest that the damage zone along the NS fault enhanced the connectivity and provided additional hydraulic channel for fluid migration during shale gas extraction. Overall, the distinct characteristics of the two earthquake clusters could be well-explained by their spatial proximity to the fault zone: shallower earthquakes occur on dense fractures near the main fault, whereas the deeper cluster occur on a distant small-scale fault. This study sheds light on the complex relationship between hydraulic fracturing, geological factors, and earthquake occurrence, and may assist strategy development toward risk mitigation of HF-induced seismicity.

How to cite: Zhang, F., Wang, R., Chen, Y., and Yu, H.: Pre-existing Fault Regulates the Distribution and Behavior of Hydraulic Fracturing-Induced Seismicity in southern Sichuan, China , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8812, https://doi.org/10.5194/egusphere-egu24-8812, 2024.

EGU24-8850 | Orals | ERE5.1

Microseismic event analysis using multi-technology sensors at the Quest CCS site 

Bettina Petra Goertz-Allmann, Nadège Langet, Alan Baird, Kamran Iranpour, Daniela Kühn, Jerome Vernier, Estelle Rebel, and Steve Oates

Microseismic monitoring plays a crucial role in assessing the effectiveness and integrity of Carbon Capture and Storage (CCS) projects. By the detection of microearthquakes we can gain real-time insights into the pressure and stress perturbation due to injection operations, aiding in the detection of potential leakage and ensuring the long-term viability of carbon sequestration efforts.

At the Quest CCS site in Alberta, Canada, CO2 injection into a 2 km depth saline reservoir is ongoing since 2015 at a rate of one million tonnes per year.  Several hundreds of small-magnitude seismic events have been located in the Precambrian basement below the reservoir.  A spatio-temporal analysis of seismicity reveals clustered as well as more diffuse distributions of events.  At the Quest site various microseismic monitoring technologies are in place including a downhole 8-level 3-component geophone string, temporary surface nodes arranged in mini-arrays, and downhole optical distributed acoustic sensing (DAS) fiber. The site offers an ideal opportunity to compare and combine the different setups with respect to event detection thresholds and location uncertainties. We demonstrate the importance of advanced signal and array processing techniques and highlight the advantages and disadvantages of different sensor technologies.

How to cite: Goertz-Allmann, B. P., Langet, N., Baird, A., Iranpour, K., Kühn, D., Vernier, J., Rebel, E., and Oates, S.: Microseismic event analysis using multi-technology sensors at the Quest CCS site, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8850, https://doi.org/10.5194/egusphere-egu24-8850, 2024.

EGU24-9417 | ECS | Posters on site | ERE5.1

Preliminary analysis of seismic attenuation and heterogeneities in Weiyuan Shale Gas Field: Coda Q and Peak delay time analysis 

Aqeel Abbas, Luca De Siena, Hongfeng Yang, Simona Gabrielli, and Wei-Mou Zhu

During hydraulic fracturing (HF) stimulation in unconventional reservoir development, seismic attenuation significantly affects high frequency microseismic data. Analyzing attenuation parameters, including scattering and absorption, provides valuable insights into reservoir properties and changes that result from HF injections. These attenuation parameters were mapped in 3D using the MuRAT (multi-resolution seismic attenuation tomography) software with a dataset of approximately 32,000 events over two years in the Weiyuan shale gas field (WSGF). Firstly, the coda quality factor Qc (intrinsic absorption), which quantifies coda wave energy loss, is calculated at large lapse time in three frequency bands (3, 6 and 9 Hz). Subsequently, we measure the peak delay time, the time lag between the direct S-wave onset and the highest amplitude arrival. Our preliminary results show that Qc has strong absorption at lower frequencies in specific volumes compared to higher frequencies. Meanwhile, peak delay times indicate consistently stronger scattering along the Weiyuan anticline and Molin fault structures across all frequency bands. We propose that the observed strong absorption is associated with the reservoir and injected fluid, while scattering is linked to pre-existing structural heterogeneities and unmapped faults.

How to cite: Abbas, A., De Siena, L., Yang, H., Gabrielli, S., and Zhu, W.-M.: Preliminary analysis of seismic attenuation and heterogeneities in Weiyuan Shale Gas Field: Coda Q and Peak delay time analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9417, https://doi.org/10.5194/egusphere-egu24-9417, 2024.

The occurrence of induced moderate to strong earthquakes is generally believed to be the reactivation of pre-existing faults of a certain size due to stress disturbances caused by the industrial activities. Therefore, pre-existing faults in the crust are already subjected to the background tectonic stress field, and different orientations of faults experience different stress state. Therefore, evaluating the risk of faults slipping with different orientations under the tectonic stress field is the basis for guiding industrial construction design to reduce induced seismic risk.

The Luxian County shale gas field is one of the four shale gas development areas in southern Sichuan, China. In this study, we conduct a fault slip risk analysis based on the distribution of the three-dimensional (3D) faults in Luxian County shale gas field . Luxian County is situated in the southwestern part of the Huayingshan fold belt, nestled between the steep Gufoshan anticline and the Luoguanshan anticline, with a broad and gentle Fuji syncline in between. The region exhibits extensive development of faults and fractures. Since the extensive implementation of hydraulic fracturing related to shale gas extraction in this region in 2019, there has been a noticeable increase in seismic activity.

In this study, we interpret the 3D fault planes in Luxian County based on seismic reflection profiles. Based on the collection of in-situ stress and formation pressure data, we establish the background tectonic stress field in the Luxian shale gas field and calculate the critical pore pressure increment required for the slipping of 3D fault planes under the background tectonic stress field, as well as the fault slip tendency. Furthermore, we construct a 3D fully coupled poroelastic finite element model to calculate the static Coulomb stress perturbation that injection operations might cause on faults. Considering the uncertainty of stress field and fault orientations, based on the Monte Carlo method, the potential of fault reactivation is calculated. Our research  provides a mechanical basis for the seismic hazard analysis of the Luxian shale gas development area, serving as an excellent example for conducting seismic hazard analysis in shale gas development fields.

How to cite: Yang, X., Tao, W., Lu, R., and Zhang, W.: Three-Dimensional Fault Slip Risk Analysis in a Shale Gas Development Area: A Case Study of the Luxian Shale Gas Field, Sichuan Basin, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10264, https://doi.org/10.5194/egusphere-egu24-10264, 2024.

EGU24-10650 | ECS | Orals | ERE5.1

Modelling of Strasbourg 2019-2020 seismicity crisis induced by geothermal operations 

Arezou Dodangeh, Renaud Toussaint, Marwan Fahs, Eirik Flekkøy, and Knut Jørgen Måløy

The risk of induced and triggered seismicity is often present in deep geothermal resources exploitation. These facilities allow exploiting practical and green energy resources.
There are many regions with high geothermal capacity, such as Alsace, France. In Vendenheim, north of Strasbourg, the Geoven plant project was expected to extract geothermal energy from the Robertsau fault by circulating fluid at depth.
Two clusters of humanly perceivable seismicity occurred in 2019-2020, one of them close to wells and other one at the Robertsau area at 5km to the south. A question was raised about a possible link between these seismic events and wells activities of Geoven site. A large distance with no earthquakes between the injection wells and the southern cluster was reason for disagreement between scientific experts and the company in charge about the link between the injection and the seismicity on this cluster.
Our objective is studying such a possible connection with numerical modeling through a simple methodology based on fluid/solid deformation and mechanical coupling. In addition, we aim at modelling the pressure perturbation during the time resulting from the history of the injection flux and comparing it with measured data.
The methodology has 3 steps: 1. Structural plan: extracting the geometry of the fault and tectonic stresses  2. Mechanical stability: the stresses on the fault are evaluated and the risk of earthquake triggering is analyzed based on Mohr-Coulomb  criterion. 3. Pore Pressure: a quasi 2D pressure diffusion equation with the proper injection parameters is solved for modeling pressure perturbation in the area due to water injection/extraction.
According to the results, the fault is strong enough in the northern cluster area and slip can happen only by high activation pressure. However, slip and micro-earthquakes resulted from large pressure increase near the wells, which is necessary for permeability increase to improve the transmissivity of  the reservoir. On the other hand, the fault is in the weakest state around the southern cluster, because the pressure required for sliding drops sharply. Indeed, with low amount of pressure increase, slip occurs. Our simulation shows that, the triggered earthquake is expected at this point, due to large enough pressure increase. But between these two clusters, not only is the fault resistant based on its orientation, but also the pore pressure increase is notlarge enough for slip. This explains, the distance of 5km between the two clusters, and absence of earthquakes in between.
Also, we simulated the pressure perturbation in the wells resulting from real injection regime data, during 85 days of operation in Geoven site in 2020, and compare it with real pressure change.
In conclusion, the lowest activation pressure in comparison to other parts can be observed around the southern cluster, which is coherent with the fault and stress tensor geometry implying a weak state in this location. Also, we identify a physical mechanism showing that earthquakes in that zone were possibly triggered by pore pressure perturbation resulting from the Geoven operation.

How to cite: Dodangeh, A., Toussaint, R., Fahs, M., Flekkøy, E., and Måløy, K. J.: Modelling of Strasbourg 2019-2020 seismicity crisis induced by geothermal operations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10650, https://doi.org/10.5194/egusphere-egu24-10650, 2024.

EGU24-11053 | ECS | Posters on site | ERE5.1

Monitoring induced seismicity in urban environment: assessing the performance of low-cost stations within Dense Semi-permanent Seismic Networks 

Riccardo Minetto, Olivier Lengliné, Marc Grunberg, Mathieu Turlure, Antoine Schlupp, Jérôme Vergne, Hélène Jund, and Jean Schmittbuhl

Obtaining high-resolution seismic catalogs from seismic data requires long-term monitoring and a sufficient number of sensors. Permanent seismic networks are usually limited to a small number of sensors, while very dense seismic networks (thousands of sensors) are typically installed for a limited period of time (days to a few weeks) and represent a large investment.

In the framework of the PrESENCE project, we test the performance of a Dense Semi-permanent Seismic Network (DSSN) deployed in an urban environment (Strasbourg Eurométropole). This network, made up of Raspberry Shake seismographs, allows to record data over long periods (years) and from dozens of sites, thanks to the use of low-cost seismic stations operated by non-seismologists.

The study aims to determine the advantages and limitations of these stations in urban environment, especially for the monitoring of induced seismicity. This is done by quantifying their impact on magnitude of completeness and location accuracy, as well as their contribution in detecting events with techniques such as template matching. The analysis was carried out on data recorded from January 2018 to September 2023 in the Strasbourg (France) area, which includes a seismic crisis that culminated in a M3.6 earthquake that led to the closure of the Geoven deep geothermal energy site operated by Fonroche-Geothermie. We conclude that these low-cost stations have provided a significant and valuable impact on the induced seismicity monitoring.

How to cite: Minetto, R., Lengliné, O., Grunberg, M., Turlure, M., Schlupp, A., Vergne, J., Jund, H., and Schmittbuhl, J.: Monitoring induced seismicity in urban environment: assessing the performance of low-cost stations within Dense Semi-permanent Seismic Networks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11053, https://doi.org/10.5194/egusphere-egu24-11053, 2024.

EGU24-11193 | ECS | Posters on site | ERE5.1

Process-based understanding of induced seismicity: a key step for public acceptance of geothermal power plants in urbanized areas  

Sofia Bressan, Giorgio Cassiani, Antonio Fuggi, and Alessandro Brovelli

Over the last century, the Earth's climate has been significantly impacted by the increasing levels of greenhouse gases in the atmosphere. To contrast this dangerous trend, the European Commission has committed approximately 17.5 billion euros to shift away from fossil fuels and embrace clean, sustainable energy sources. The ambitious goal is to achieve a substantial reduction of at least 55% in greenhouse gas emissions by 2030, while simultaneously boosting the use of renewable energy sources by approximately 40%. In this socio-cultural context, geothermal energy emerges as an promising, sustainable, and renewable resource that could potentially satisfy the world's escalating energy demand. Nevertheless, despite its considerable advantages, geothermal energy faces a challenge due to insufficient public backing. Among the main causes of this reluctance are the concerns about possible triggering of seismic events during geothermal operations. Recent studies reveal that more than half of anthropogenic activities leading to induced earthquakes are associated with the extraction or injection of underground fluids.

This phenomenon necessitates a detailed examination of the complex interplay between various physical and chemical factors influencing the subsurface dynamics. The complexities of induced seismicity go beyond singular mechanistic explanations. Temperature, volume, and multi-phase nature of the fluid have important physical-chemical implications for stimulated rock volume. These behaviors are well known to the scientific community, which has conducted multidisciplinary research to emphasize that the development of anthropogenic seismic events does not result from a single mechanism but from the interaction of multiple factors, such as perturbations of the stress state, changes in pore pressure, the interactions between pre-existing structures in the area or the dynamic weakening of seismogenetic faults. Despite extensive multidisciplinary research, the coexistence and influence of these processes on earthquake development remain unclear. Addressing this knowledge gap is crucial for developing effective prediction and mitigation strategies.

What are the most recent theories on the generation of anthropogenic earthquakes? Can physics-based models help us better understand the mechanics behind these events and mitigate their development?

This abstract aim is to collect and summarise the most recent information on anthropogenic earthquakes associated with geothermal activities. This review will be the basis for a three-year PhD programme that will evaluate existing theories, compare proposed approaches, and determine the most viable avenues for developing prediction or mitigation techniques. The methodology will involve a comprehensive analysis, starting with structural and geophysical assessments, followed by numerical modelling to improve understanding of the underlying fluid and rock mechanics. The objective will be to develop effective and understandable strategies to address the problems associated with geothermal-induced seismicity.

How to cite: Bressan, S., Cassiani, G., Fuggi, A., and Brovelli, A.: Process-based understanding of induced seismicity: a key step for public acceptance of geothermal power plants in urbanized areas , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11193, https://doi.org/10.5194/egusphere-egu24-11193, 2024.

EGU24-11558 | ECS | Orals | ERE5.1

Fluid-induced earthquake nucleation controlled by shear-induced compaction and dilation 

Luca Dal Zilio, Paul Selvadurai, Taras Gerya, Jean-Paul Ampuero, Elisa Tinti, Massimo Cocco, Frédéric Cappa, Stefan Wiemer, Domenico Giardini, and the FEAR team

The conventional understanding of tectonic faults primarily categorizes them based on frictional behavior: stable due to velocity-strengthening (VS) behavior, or unstable owing to velocity-weakening (VW) that lead to seismic ruptures. This classification has traditionally led to the assumption that VS faults are unlikely candidates for earthquake nucleation. However, emerging evidence from recent laboratory experiments and field studies is challenging this simplistic view, pointing towards a more complex mechanism. In this study, we utilize a hydro-mechanically coupled fault model, which integrates VS friction governed by rate-and-state friction laws with dynamic weakening influenced by poroelastic effects. A key aspect of our findings is the impact of fluid injection on the mechanical state of the fault. This process decreases the effective normal stress and frictional resistance, initially paving the way for the propagation of an aseismic, slow-slip event. The transition from aseismic to seismic slip on VS faults hinges on the balance between shear-induced dilation and compaction. These opposing mechanisms respectively lead to a decrease and an increase in pore-fluid pressure, dictating the balance between fault stability or instability. Our results show that when the effect of compaction-induced pressurization surpasses the initial dilatancy phase, it enables the propagation of dynamic rupture as a solitary pore-pressure wave. Conversely, when dilation predominates over compaction, an aseismic slow-slip event propagates through the fault, maintaining stability and preventing rapid seismic activity. These findings advance our understanding of seismic risk associated with VS faults. They are especially relevant in the context of fluid injection practices in geothermal energy production and CO2 storage, demonstrating how such activities might activate faults that are considered nominally stable. Additionally, our results underscore the critical need for more experimental and theoretical investigations into shear-induced compaction as an efficient mechanism for fault self-pressurization, which plays a key role in leading to seismic instabilities.

How to cite: Dal Zilio, L., Selvadurai, P., Gerya, T., Ampuero, J.-P., Tinti, E., Cocco, M., Cappa, F., Wiemer, S., Giardini, D., and FEAR team, T.: Fluid-induced earthquake nucleation controlled by shear-induced compaction and dilation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11558, https://doi.org/10.5194/egusphere-egu24-11558, 2024.

EGU24-12822 | ECS | Orals | ERE5.1

Frictional Properties of Simulated Fault Gouges subject to Normal Stress Oscillation and Implications for Induced Seismicity 

Bowen Yu, Jianye Chen, Christopher J. Spiers, and Shengli Ma

Under critical conditions where fault slip exhibits self-sustained oscillation in experiments, effects of normal stress oscillation (NSO) on fault strength and stability remain uncertain, as do potential effects of NSO on natural and induced seismicity. In this study, we employed double direct shear testing to investigate the frictional behavior of a synthetic, near velocity-neutral (VN) fault gouge (characterized by self-sustained oscillation under quasi-static shear loading), when subjected to NSO at different amplitudes and frequencies. During the experiment, fault displacement and gouge layer thickness were measured. Transmitted ultrasonic waves were also employed to probe grain contact states within the gouge layer. Our results show that fault weakening and unstable slip can be readily triggered by oscillations, depending on oscillation frequency and amplitude. Interestingly, an amplified shear stress drop and weakening effect were observed when the oscillation frequency fell in a specific range (0.01–0.1Hz). No such effects were seen in a velocity-strengthening gouge. Analysis of transmitted ultrasonic waves in the test on the VN gouge reveals the presence of fault dilatation, accompanied by unstable slip and weakening. By extending an existing microphysical model (the "CNS” model), to account for elastic effects of NSO on gouge microstructure and grain contact state, the mechanical and wave data obtained in our experiment on the VN gouge was reproduced. Assisted by the microphysically-based friction model, resolving the instability criterion of a velocity-neutral fault under perturbation is crucial for understanding and thus predicting the fault behaviors of certain scenarios, like periodic gas storage in deep reservoirs.

How to cite: Yu, B., Chen, J., Spiers, C. J., and Ma, S.: Frictional Properties of Simulated Fault Gouges subject to Normal Stress Oscillation and Implications for Induced Seismicity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12822, https://doi.org/10.5194/egusphere-egu24-12822, 2024.

EGU24-12860 | Orals | ERE5.1

Forecasting and characterizing induced seismicity at the Utah FORGE EGS site 

Federica Lanza and Stefan Wiemer and the DEEP Team

Managing induced seismicity risk is an absolute must to enable the widespread use of deep geothermal technologies, and thus contribute to the transformation towards a sustainable and low-carbon energy sector. A full-scale application of real-time monitoring and forecasting of induced seismicity was tested in April 2022, during a three-stage hydraulic stimulation in a deep granite heat reservoir of low permeability at the Utah FORGE EGS site. During the stimulation, a total of ~1600 m3 pressurized fluids were injected into the target reservoir of ~2.4 km depth to generate fracture networks and improve reservoir permeability for heat extraction. Stage 3 had the most complete monitoring network and thus was used to test the components of an Adaptive Traffic Light System (ATLS). The test produced very positive results, although the data stream was lost early into the stimulation.

Here, we further characterize and perform a retrospective forecasting of post-processed data related to the induced seismicity recorded during stage 3 of the 2022 stimulation at FORGE site. We first investigate the geometrical distribution of the seismicity and discuss it in the context of the stress field at FORGE injection site. The statistical inference indicates that the distribution of the seismicity lies on a plane sub-parallel to the Sv - SHmax and orthogonal to SHmin, and with strike orientation rotated 10o counterclockwise with respect to the N25oE average orientation of SHmax. The analysis seems to indicate that seismicity is induced by a tensile fracture, although we cannot completely rule-out seismic activity on a pre-existing fault. Gutenberg-Richter b-value variations in space are compatible with large magnitude events occurring at the edges of the earthquake propagating front. We further investigate the possible fracturing mechanisms triggered by the injection operation by fitting three plausible physical models: (1) a high-pore pressure diffusion model, (2) an aseismic crack model, and (3) a penny-shaped tensile crack model as the causative process of the recorded seismicity. The analysis of the seismicity evolution alone allows us to fit the three considered scenarios to the data independently, however we cannot exclude a combination of the three processes acting together. Through pseudo-retrospective forecasting, we then replay the induced seismicity as it was happening in real-time. We demonstrate that even if the physical processes are complex and likely difficult to disentangle using the seismicity alone, a simple empirical statistical seismicity rate forecasting model has stable predictability of hydraulic fracturing.

How to cite: Lanza, F. and Wiemer, S. and the DEEP Team: Forecasting and characterizing induced seismicity at the Utah FORGE EGS site, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12860, https://doi.org/10.5194/egusphere-egu24-12860, 2024.

EGU24-13824 | ECS | Posters on site | ERE5.1

The QuakeMatch Toolbox: Using waveform similarity to enhance the analysis of microearthquake sequences at Swiss geothermal projects  

Tania Toledo, Verena Simon, Toni Kraft, Veronica Antunes, Marcus Herrmann, Tobias Diehl, and Linus Villiger

 

Many Swiss microearthquake sequences have been analyzed using relative location techniques. While these methods have often been effective in identifying active fault planes and the tectonic processes driving the seismic activity, several sequences present a limited number of located events. This limitation often hampers the detailed analysis of their space-time evolution, seismicity patterns, and driving mechanisms. 

 

To address this challenge, we introduce a nearly automatic workflow that combines established seismological analysis techniques to enhance the completeness of detected and located earthquakes within a sequence. Starting with a manual catalog (magnitude of completeness, Mc ≈ 1.0−1.5 ML), we compile a template set and conduct a matched filter analysis on a single station with the highest signal-to-noise ratio (SNR). This approach enables the detection of events with local magnitudes ML < 0.0, with waveform similarity further leveraged to determine consistent magnitudes for these detections. The enhanced catalog is statistically analyzed to obtain high-resolution temporal evolutions of the Gutenberg−Richter a- and b-values, and consequently, the occurrence short-term probability of larger events. Finally, strong events are relocated by the double-difference technique, typically improving the final number of relocated events by a factor of 2-5. 

 

The proposed workflow significantly improves the analysis of the spatiotemporal behavior of natural and induced microearthquake sequences. Notably, we employ it for semi real-time monitoring of commercial and scientific fluid-injection projects. The QuakeMatch workflow is implemented in Python and PostgreSQL. We discuss the capabilities of QuakeMatch through examples involving induced microearthquake sequences associated with various geothermal projects monitored by the Swiss Seismological Service within the GEOBEST2020+ project. 

How to cite: Toledo, T., Simon, V., Kraft, T., Antunes, V., Herrmann, M., Diehl, T., and Villiger, L.: The QuakeMatch Toolbox: Using waveform similarity to enhance the analysis of microearthquake sequences at Swiss geothermal projects , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13824, https://doi.org/10.5194/egusphere-egu24-13824, 2024.

EGU24-13991 | ECS | Posters on site | ERE5.1

Earthquake behaviors for moderate to strong induced events are controlled by high-velocity bodies near shale reservoirs in southern Sichuan basin, China 

Jian Xu, Junlun Li, Haijiang Zhang, Wen Yang, Yuyang Tan, Chang Guo, Siyu Miao, and Zhengyue Li

Moderate to strong earthquakes have been induced worldwide by shale gas development. However, it is still unclear what factors control the occurrence and magnitude of moderate to strong earthquakes induced by hydraulic fracturing. By using a permanent local seismic network and a temporary dense seismic network, we reliably determined the source attributes of dozens of earthquakes with magnitudes M>3, and importantly, a high-resolution shear-wave velocity model is obtained for studying the detailed seismogenic structure of an unconventional oil/gas field using ambient noise tomography. These earthquakes are found to occur close to the target shale formations in depth, and along high seismic velocity boundaries. Especially, the 2018 Xingwen 5.7 and 2019 Gongxian 5.3 induced earthquakes nucleated around the edges of high velocity zones. These two M>5 earthquake magnitudes as well as co-seismic slip distributions are further determined jointly by seismic waveforms and InSAR data and are found correlated with the high velocity zones along the fault planes. Thus, the distribution of high velocity zones near the target shale formations, together with the stress state modulated by hydraulic fracturing controls induced earthquake behaviors and is critical for understanding the seismic potentials associated with hydraulic fracturing.

How to cite: Xu, J., Li, J., Zhang, H., Yang, W., Tan, Y., Guo, C., Miao, S., and Li, Z.: Earthquake behaviors for moderate to strong induced events are controlled by high-velocity bodies near shale reservoirs in southern Sichuan basin, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13991, https://doi.org/10.5194/egusphere-egu24-13991, 2024.

EGU24-14139 | ECS | Orals | ERE5.1

Deciphering Seismogenic Patterns in Hydraulic Fracturing: A Machine Learning Approach in the Southern Montney Play 

Bei Wang, Honn Kao, Hongyu Yu, Ge Li, Ramin M.H. Dokht, and Ryan Visser

The burgeoning development of hydraulic fracturing (HF) for unconventional resource extraction has been paralleled by a rise in injection-induced earthquakes (IIEs), posing significant seismic hazards. A critical challenge in mitigating these hazards is the accurate assessment of the seismogenic potential and earthquake productivity of individual HF pads. We addresses this challenge by analyzing over 35,000 earthquakes in the Southern Montney Play (SMP), Western Canada, from 2014 to 2022, and associating them with 357 HF pads.

 

We employed the eXtreme Gradient Boosting (XGBoost) machine-learning algorithm, integrating fifteen geological and operational factors to evaluate their influence on IIE occurrence and intensity. We also utilized Shapley Additive Explanations (SHAP) values for a nuanced interpretation of the model outputs, providing insights into the relative importance and interaction of these factors.

 

Our analysis reveals that the cumulative injected volume and the location of HF pads within the Fort St. John Graben (FSJG) are the primary determinants of seimogenic potential (occurrence of IIE). In contrast, the number of HF stages targeting the Lower Middle Montney formation, cumulative volume from preceding injections, and the HF pad's location within the FSJG predominantly influence the seismogenic productivity (number of IIE). These findings suggest that both operational and geological factors are critical in determining the seismogenic productivity of HF pads. The XGBoost model demonstrated high predictive accuracy (R2 ~0.90), although its performance is constrained by the dataset's size and potential overfitting issues.

 

The study challenges the conventional understanding that proximity to known faults is a major factor in IIE occurrence, instead highlighting the significance of cumulative injection volumes and specific geological settings. The analysis also underscores the complex interplay between various factors, such as the correlation between the location fo the HF pads and the targed formation during HF stimulations, which may influence seismogenic patterns.

 

Overall, our result provides a comprehensive assessment of the factors influencing seismogenic behavior in HF-related IIEs, paving the way for more accurate forecasting of IIE activity levels for individual HF pads in the SMP. The findings have significant implications for seismic hazard assessment and risk mitigation strategies in regions undergoing HF operations. The application of machine learning in this context not only enhances our understanding of induced seismicity but also demonstrates the potential of such techniques in addressing complex geoscientific challenges.

How to cite: Wang, B., Kao, H., Yu, H., Li, G., M.H. Dokht, R., and Visser, R.: Deciphering Seismogenic Patterns in Hydraulic Fracturing: A Machine Learning Approach in the Southern Montney Play, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14139, https://doi.org/10.5194/egusphere-egu24-14139, 2024.

EGU24-14828 | ECS | Orals | ERE5.1

Spatio-temporal evolution of hypocenters and moment tensors derived from time-reverse imaging 

Claudia Finger, Katinka Tuinstra, Peter Niemz, Peidong Shi, Laura Ermert, and Federica Lanza

The location and focal mechanism of microseismicity induced during fluid injection experiments in geothermal wells can be used to infer the extent of fracturing and the orientation of the local stress field. Passive seismic instrumentation is typically deployed at the surface and in boreholes around the injection site to monitor microseismic activity. Recent methodological advancements enable locating the often thousands of seismic events in a timely fashion. However, the determination of focal mechanisms is often limited to a selected number of larger-magnitude events.

 

Time-Reverse Imaging (TRI) exploits the time-invariancy of the elastic seismic wavefield to propagate the seismic wavefield backwards in time from seismic stations through an adequate velocity model. Under ideal conditions, the wavefield will converge on the initial source location at the origin time. The excellent location accuracy for events with signal-to-noise ratios smaller than one and the capability of determining the moment tensor for each locatable event has been demonstrated in controlled synthetic and real studies. Numerous improvements and adaptations have been proposed to augment the resulting image volume used to identify individual seismic events. TRI is a promising one-stop solution for analyzing microseismicity but has two major disadvantages: (1) the computation time needed to simulate the high-frequency elastic wavefield prohibits the analysis of continuous hours or days of microseismic recordings, and (2) the identification of individual seismic events from TRI image volumes is susceptible to overestimating the number of seismic events due to noisy images.

 

Alterations of the TRI concept based on pre-computed Green’s functions exist and provide a near-real time solution but require compromises in terms of location accuracy and minimal signal-to-noise ratio. The focal mechanism cannot be identified yet with these types of methods. Thus, the main challenge of applying TRI is reducing the needed computational time, while retaining most beneficial capabilities. This balancing act requires a careful analysis of possible compromises through careful scaling of simulation parameters.

 

Here, we apply TRI to synthetic seismic recordings created with the sensor setup deployed during the injection experiment in April 2022 at the UtahFORGE test site. A combined elastic velocity model of the complex site geology is used with a network including real locations of fiber optic cables, deep and shallow borehole sensors, and nodal seismic sensors. This synthetic data is used to demonstrate the accuracy gain of using multiple types of sensors and the speed gain of using characteristic functions applied to the seismic recordings prior to back propagation. Accuracy and speed are compared for synthetic and real test cases to optimize their trade-off. Finally, instead of individually picking seismic events, we demonstrate the usefulness of interpreting the spatio-temporal evolution of hypocenters and moment tensors directly from the TRI results.

How to cite: Finger, C., Tuinstra, K., Niemz, P., Shi, P., Ermert, L., and Lanza, F.: Spatio-temporal evolution of hypocenters and moment tensors derived from time-reverse imaging, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14828, https://doi.org/10.5194/egusphere-egu24-14828, 2024.

EGU24-14916 | Posters on site | ERE5.1

The Impact of Injection Protocol and Stress Preconditioning on the Hydro-Mechanical Response of the Crystalline Rock 

Mohammadreza Jalali, Paul Selvadurai, Elena Spagnuolo, Men-Andrin Meier, Luca Dal Zilio, Nima Gholizadeh Doonechaly, Kai Bröker, Julian Osten, Martina Rosskopf, Anne Obermann, and Florian Amann and the FEAR Team

Hydraulic stimulation has been extensively utilized in the geothermal industry as the primary technique to create and develop an efficient heat exchanger in a low-permeable reservoir rock. This technique entails high-pressure fluid injection under various injection schemes to perturb the local stress field at both borehole and reservoir scales, leading to permanent permeability enhancement of the stimulated volume through shear dislocation and dilation. These stress disturbances can also potentially trigger and/or induce seismicity in the reservoir and beyond. Understanding how different injection protocols serve as a preconditioning tool and their impact on the hydro-mechanical response of the stimulated volume would enhance our understanding of geothermal reservoir enhancement and induced seismicity mitigation.

In the preparatory phase of the FEAR (Fault Activation and Earthquake Rupture) project in Bedretto Underground Laboratory (Switzerland), various injection protocols were utilized to understand the hydro-mechanical responses of the stimulated volume as well as earthquake rupture processes such as nucleation and premonitory slip. The adopted injection protocols include a) constant pressure injection for a specific time followed by step-rate injection and b) constant pressure withdrawal for a specific time followed by step-rate injection. In both protocols, an approximately equal amount of water (~3000 liters) was injected over the stimulation phase. Each injection protocol was associated with the pre- and post-characterization tests such as HTPF (hydraulic tests on pre-existing fractures) tests. Hydro-mechanical response of the host rock during these tests was monitored using various pressure, strain, and acoustic emission sensors in the injection and monitoring boreholes.

At first glance, there appears to be no significant difference in the hydro-mechanical responses as well as the seismicity pattern of these two injection protocols, yet deeper investigation mostly based on the strain data reveals that strategy a) produced more heterogeneity in strain rate on the fiber-optic array whereas b) produced a more homogenized response. Numerical modelling and an experimental campaign in the laboratory are now underway to better understand the underlying mechanisms producing this response with the aim to best select a proper injection protocol for the goal of the FEAR project.

How to cite: Jalali, M., Selvadurai, P., Spagnuolo, E., Meier, M.-A., Dal Zilio, L., Gholizadeh Doonechaly, N., Bröker, K., Osten, J., Rosskopf, M., Obermann, A., and Amann, F. and the FEAR Team: The Impact of Injection Protocol and Stress Preconditioning on the Hydro-Mechanical Response of the Crystalline Rock, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14916, https://doi.org/10.5194/egusphere-egu24-14916, 2024.

EGU24-15394 | Orals | ERE5.1

Microseismic monitoring and insights of rupture mechanism from China's pilot EGS project in Gonghe, Northwestern China 

Hao Zhang and the Hao Zhang, Institute of Geomechanics, Chinese Academy of Geological Sciences

Enhanced Geothermal Systems (EGS) are effective means of developing hot dry rock (HDR) type geothermal resources, transforming low porosity and permeability rock masses deep underground into artificial geothermal reservoirs with high permeability through reservoir stimulation. EGS systems can economically extract a considerable amount of thermal energy over the medium to long term to be utilized for power generation. The development and research of EGS has been ongoing internationally for over 40 years. However, at present, the development of EGS is still in the stage of on-site experimental research and development, and its commercial development still faces many challenges. China, like many other countries, is in need of developing deep geothermal resources to meet its energy demands. In 2017, a well named GR1 with a temperature of 236°C was drilled to a depth of 3705m in the Gonghe Basin of Qinghai Province. Recognizing the potential of HDR resources, the China Geological Survey launched an exploration and production project in Gonghe Basin in 2019. Following several critical technological breakthroughs, the first power generation test of HDR was successfully conducted in the Gonghe Basin in 2022. This study offers a detailed introduction to the localization of microseismic events that occurred during thermal reservoir stimulation at different stages of development. By analyzing these microseismic events, we can evaluate the effectiveness and volume scale of artificial thermal reservoir transformation. In addition, we assess the development of natural fractures utilizing data from 3D seismic attributes of the granite, imaging logging, etc. We conclude by discussing implications for successful geothermal development of the specific geological conditions present at the Gonghe HDR field, based on the localization results of microseismic data and the distribution of natural fractures in the field.

How to cite: Zhang, H. and the Hao Zhang, Institute of Geomechanics, Chinese Academy of Geological Sciences: Microseismic monitoring and insights of rupture mechanism from China's pilot EGS project in Gonghe, Northwestern China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15394, https://doi.org/10.5194/egusphere-egu24-15394, 2024.

EGU24-15485 | ECS | Posters on site | ERE5.1

Microseismic monitoring and characteristic analysis for underground coal mining: A case study from Xiaobaodang coal mine, China 

Zhichao Yu, Yuyang Tan, Kaige Gao, Yiran Lv, and Cindy He

Coal mining disrupts the stress equilibrium of the surrounding rock mass, and the rock mass cracks as a result of the changes in the stress field, releasing strain energy and causing microseismic events. Monitoring seismicitiy during coal mining is critical for ensuring safe production and preventing geological disasters. In this study, we deployed 29 surface seismic nodes above an underground coal mine in the Yulin region of Shaanxi Province, China, to monitor the mining operation for 665 hours. A large number of microseismic events have been detected from continuous monitoring data, and analyzed using event clustering, source location, and mechanism estimate. The results show that (1) the frequency and intensity of microseismic events are related to underground mining working conditions; (2) the temporal and spatial locations of the microseismic sources may be utilized for real-time tracking the location of the underground coal mining face; and (3) three rupture mechanisms of tension rupture, implosion rupture, and shear rupture reflect the triggering mechanisms of the coal pillar failure, roof breakage and movement and fault slip. 

How to cite: Yu, Z., Tan, Y., Gao, K., Lv, Y., and He, C.: Microseismic monitoring and characteristic analysis for underground coal mining: A case study from Xiaobaodang coal mine, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15485, https://doi.org/10.5194/egusphere-egu24-15485, 2024.

EGU24-15621 | ECS | Orals | ERE5.1

Machine learning based real-time microseismic monitoring and stimulated fracture characterization at the Utah FORGE Geothermal site 

Peidong Shi, Ryan Schultz, Federica Lanza, Luca Scarabello, Laura Ermert, and Stefan Wiemer

In April 2022, a three-stage hydraulic stimulation was performed in a deep granite heat reservoir of low permeability at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE). During the stimulation, around 1600 m3 pressurized fluids were injected into the target reservoir of ~2.4 km depth aiming at creating fracture networks and improving reservoir permeability for heat extraction. Microseismic monitoring is required to assess the stimulation efficiency and manage the induced earthquake risk during the stimulation. We perform near-real-time microseismic monitoring in a playback mode at the third stage of the stimulation where three deep monitoring boreholes equipped with three-component geophone chains were in operation. We apply machine learning (ML) techniques in combination with waveform back projection approaches to automate the microseismic event detection, increase microseismic event location accuracy, and promote the real-time capability of the monitoring workflow. Due to a lack of labeled datasets for model training or transfer learning, we devise a rescaling technique to tune the continuous microseismic recordings of high sampling rates that enables the application of existing ML models pre-trained on tectonic earthquakes. Our benchmark tests show that the proposed rescaling approach achieves high precision and accuracy in detecting microseismic events and picking their phase arrivals.

With the proposed workflow, we compiled a high-resolution microseismic catalog containing around 36, 000 microseismic events with magnitudes of –3.0 to 0.5. Detected events are relocated using a double-difference relocation method and waveform cross-correlation-based arrivaltime refinement. We cluster the detected microseismic events according to their spatial distributions and identify the dominant stimulated fracture planes with principle component analysis of the different event clusters. The spatial distribution of the detected events nicely depicts the stimulated fracture networks which can be used to design the trajectory of the future production well. We analyze the spatio-temporal evolution of the induced microseismic events during and after the stimulation to illuminate the rupturing mechanisms responsible for the induced fracture networks. Induced microseismic events are analyzed together with the injection data to quantify the induced earthquake hazard and the hydraulic stimulation efficiency. The proposed microseismic monitoring workflow and the corresponding analysis provide more insights into the fracturing dynamics and the potential induced earthquake hazard in the Utah FORGE geothermal site, and would benefit the operation of other enhanced geothermal systems.

How to cite: Shi, P., Schultz, R., Lanza, F., Scarabello, L., Ermert, L., and Wiemer, S.: Machine learning based real-time microseismic monitoring and stimulated fracture characterization at the Utah FORGE Geothermal site, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15621, https://doi.org/10.5194/egusphere-egu24-15621, 2024.

EGU24-16552 | ECS | Posters on site | ERE5.1

Passive monitoring of a deep geothermal reservoir in the Strasbourg area by interferometric approaches using ambient seismic noise. 

Flavien Mattern, Jérôme Vergne, Jean Schmittbuhl, and Dimitri Zigone

We present preliminary results of ambient seismic noise monitoring near the deep geothermal reservoir at the Vendenheim site north of Strasbourg in France. From November 2019 to mid 2021, various operations led to an intense induced seismic swarm with several events of magnitudes above 3.0Mlv. This crisis is also characterized by the presence of an isolated swarm ~5km south of the geothermal site as well as the occurrence of the maximum magnitude event (3.9Mlv) 6 months after the cease of injection tests. Understanding these remote and delayed triggering mechanisms is essential for the successful development of future deep geothermal projects. We use ambient seismic noise correlations betweens pairs of sensors from a composite network of 137 permanent and temporary stations in the area. In particular, we intend to monitor the evolution of the upper crust around the reservoir by studying velocity variations and coda waveforms decorrelation in different frequency bands.

At high frequencies (1-3Hz), velocity variations appear to be correlated with fluctuations of the water table elevation. Strong decorrelations in waveform coda are also observed during holidays, suggesting changes in anthropogenic noise sources illumination. At low frequencies (3-6s), apparent variations of velocity and decorrelation with mainly an annual periodicity are observed, but could be associated with seasonal variations in the position of the sources of the second microseismic peak. This study shows that in order to observe temporal variation in the properties of deep geothermal reservoirs with ambient noise coda wave interferometry, it is necessary to understand and model variations in the subsurface layers and in the sources of ambient seismic noise.  

How to cite: Mattern, F., Vergne, J., Schmittbuhl, J., and Zigone, D.: Passive monitoring of a deep geothermal reservoir in the Strasbourg area by interferometric approaches using ambient seismic noise., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16552, https://doi.org/10.5194/egusphere-egu24-16552, 2024.

EGU24-16938 | ECS | Orals | ERE5.1

Stress and Strain Changes in Response to Reservoir Water Level Variations – A Case Study of the Enguri High-Head Arch Dam in the Caucasus 

Thomas Niederhuber, Birgit Müller, Malte Westerhaus, Andreas Rietbrock, Jakob Weisgerber, Thomas Röckel, Nasim Karamzadeh, Nino Tsereteli, Nazi Tugushi, Mirian Kalabegishvili, David Svanadze, and Frank Schilling

Hydropower facilities utilize the potential energy of water to generate electricity, with maximum efficiency achieved when there is a significant topographic gradient between reservoir and turbines. Therefore, high dams are typically built in regions with rugged topography, often associated with (frequently combined) erosion, folding or displacement along fault zones, leading to juxtaposed different material properties.

At the Enguri Arch Dam in Georgia, extensive limestone formations from the Cretaceous and Jurassic were thrust southward, resulting in a topography difference exceeding 1000 m between the southward-extending Rioni Basin and the contiguous mountain ranges. The reservoir extends about 25 km to the north. There, nearby mountains reach heights of 3000 m and more. As part of the ongoing crustal shortening process, multiple fault systems have emerged, including prominent SW-NE trending thrust faults, steep strike-slip faults, and to a minor extend normal faults.

The Enguri valley carves into the surrounding mountains, reaching an elevation of 280 m above sea level at the dam site. These substantial topographic variations between hilltops and valleys establish a variable initial stress field characterized by lateral heterogeneity in both magnitude and orientation. The initial stress conditions were determined using borehole imaging data and hydraulic fracturing tests, while the mechanical properties of the subsurface materials were evaluated using mechanical tests on core samples.

The Enguri high-head Dam has a construction height of 271 m and the Jvari-reservoir reaches at full level more than 510 m above sea level. Geodetic GNSS and seismic stations were installed to evaluate the impact of the annual water level changes of about 100 m on the surrounding area.

The subsurface information on stress conditions and material properties was used to create an elastic 3D model of the area. The modelling results were compared with field observations to gain a better understanding of the dynamic processes in the area. In a first step the initial stress field was simulated. Loads were applied to simulate the water level changes. Modelled and observed displacements indicate that rising water level causes the west bank to move north-west, while the east bank moves south-east. Furthermore, both banks of the valley show a downward movement. Conversely, when the water level decreases, the effect is reversed. Variations in water level induce changes in the shear stress and changes in Coulomb Failure Stress (ΔCFS) calculated for different fault orientations. They reveal an increased seismic potential during low water levels, aligning with first seismic observations.

How to cite: Niederhuber, T., Müller, B., Westerhaus, M., Rietbrock, A., Weisgerber, J., Röckel, T., Karamzadeh, N., Tsereteli, N., Tugushi, N., Kalabegishvili, M., Svanadze, D., and Schilling, F.: Stress and Strain Changes in Response to Reservoir Water Level Variations – A Case Study of the Enguri High-Head Arch Dam in the Caucasus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16938, https://doi.org/10.5194/egusphere-egu24-16938, 2024.

EGU24-18907 | ECS | Orals | ERE5.1

The duration of injection protocol likely controls the maximum magnitude of induced earthquakes 

Mohammad JA Moein, Cornelius Langenbruch, and Serge Shapiro

High-pressure fluid injection into subsurface is often carried out to enhance the permeability of deep geothermal reservoirs. The operation sometimes triggers induced earthquakes that may be as large as natural earthquakes. Novel injection protocols such as cyclic injection schemes have been proposed to mitigate the risk of inducing larger events. Currently, the of impact cyclic injection schemes on the maximum magnitude Mmax is not fully understood. Here, the working hypothesis  is that the pore-pressure diffusion is the dominant triggering mechanism of induced events and the maximum induced earthquake scales with the pressure-perturbed fault size. We developed a first-order hydrogeological model and simulated the fluid injection into a porous rock with an embedded large-scale fault zone. Different injection scenarios were implemented, and the pressure-perturbed fault size was computed and translated to the maximum induced earthquake magnitude. The numerical models showed that the duration of the injection protocol plays an important role and likely controls the occurrence of larger-magnitude events. Our numerical models can provide significant insight into the effectiveness of mitigation strategies during the engineering of Enhanced Geothermal Systems and underground storage reservoirs.

How to cite: Moein, M. J., Langenbruch, C., and Shapiro, S.: The duration of injection protocol likely controls the maximum magnitude of induced earthquakes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18907, https://doi.org/10.5194/egusphere-egu24-18907, 2024.

EGU24-18935 | Posters on site | ERE5.1

The contribution of pore fluid pressure to earthquakes induced in St. Gallen geothermal field, Switzerland 

Raffaella De Matteis, Bruno Massa, Guido Maria Adinolfi, Ortensia Amoroso, Toshiko Terakawa, and Vincenzo Convertito

In July 2013, a sequence of more than 340 earthquakes was induced during the deep geothermal drilling project close to the city of St. Gallen in Switzerland. Induced seismicity represents a disadvantage during sub-surface geoenergy operations, so understanding the underlying triggering mechanisms is crucial for mitigating the seismic hazard.  To this end, we investigate the role of fluids and elastic stress transfer as driving mechanisms of the St. Gallen seismic sequence. Following the underlying idea of the Focal Mechanism Tomography technique, we estimate the excess pore fluid pressure at the hypocenters of earthquakes from the analysis of their focal mechanisms. The uncertainties on the focal mechanism parameters, friction coefficient and rock density are taken into account using a Monte Carlo approach to calculate the effect on the estimated excess pore pressure. The results indicate that, in addition to Coulomb static stress change, high-pressure fluids had a primary role in the earthquake triggering. Unlike what is observed in other geothermal fields, the value of the calculated excess pore fluid pressure is higher than the injection pressure for approximately half of the earthquakes. This can likely be attributed to the accidental release of overpressured gas (gas kick) that occurred during field operations when the seal to a gas reservoir was broken.

 

This work has been supported by PRIN-2017 MATISSE project (No. 20177EPPN2), funded by Italian Ministry of Education and Research.

 

How to cite: De Matteis, R., Massa, B., Adinolfi, G. M., Amoroso, O., Terakawa, T., and Convertito, V.: The contribution of pore fluid pressure to earthquakes induced in St. Gallen geothermal field, Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18935, https://doi.org/10.5194/egusphere-egu24-18935, 2024.

EGU24-20416 | Orals | ERE5.1

Comparing water-disposal and CO2-storage induced earthquakes 

Cornelius Langenbruch and Serge Shapiro

To date, only several small-scale CO2 storage projects, injecting about 1 Mt of CO2 per year, exist worldwide. Induced seismicity has been recorded during operation. Overall, magnitudes of the seismic events are small (below M=3). Nevertheless, there is the concern that future large-scale projects will induce significantly larger magnitudes, like it is observed for basin-scale waste-water disposal. For instance, large-scale water disposal in Oklahoma and Kansas (USA) induced thousands of widely felt M3+ earthquakes with a maximum magnitude of M=5.8. We analyze seismicity and injection data from CO2-storage projects including Quest (CA), Decataur (USA), In-Sahla (Algeria), Otway (AUS) and Gorgon (AUS). We compute the normalized seismic response of the subsurface to injection of a unit volume of CO2 using the Seismogenic Index (SI) and compare it to water-disposal case studies. We find that the SI at CO2-storage sites is smaller compared to water-disposal cases. It indicates a lower seismic hazard per injected volume of CO2. We discuss physical processes that could explain our observations and show how earthquake magnitude probabilities can potentially be upscaled, considering CO2 storage volumes needed in the future.

How to cite: Langenbruch, C. and Shapiro, S.: Comparing water-disposal and CO2-storage induced earthquakes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20416, https://doi.org/10.5194/egusphere-egu24-20416, 2024.

EGU24-4423 | Orals | ERE5.2 | Highlight

A comprehensive petrophysical databank of crystalline reservoirs for assessing deep geothermal exploration targets in Finland and abroad 

Michael Heap, Alan Bischoff, Toni Luoto, Thierry Reuschlé, Satu Vuoriainen, Marion Spitz, and Marianne Leon-Stackow

Context

As part of the Deep-HEAT-Flows project (https://deep-heat-flows.voog.com), we have collected a comprehensive geological and petrophysical dataset of crystalline reservoirs formed within fault zones and at the contact of igneous intrusions across Finland, evaluating their potential as deep geothermal reservoirs. Our investigations involve a range of laboratory-based experiments encompassing measurements of rock density, elastic wave velocity, electric resistivity, porosity, and permeability under various confining pressures, and the thermal properties of 120+ samples collected from diverse crystalline rocks. Additionally, we apply mineral and pore space caracterization techniques including petrography, micro-XRF spectrometry, SEM-EDS, hyperspectral imaging, and CT scans to understand the processes that control crystalline reservoir formation.

Findings

Our findings highlight a common trend among various petrophysiscal parameters: rock density, resistivity, elastic wave velocity, thermal conductivity, and heat capacity typically reduce as the porosity increases, a characteristic observed across many sedimentary and volcanic rocks. Reservoir quality is primarily determined by the morphology of the pore network, encompassing fractures and interconnected moldic, sieve, and interparticle pores. The most promising reservoir properties were observed in rocks intersected by regional shear zones and therefore affected by intense brecciation, cataclasis, and hydrothermal alteration, leading to a notable porosity of ~20% and permeability in the order of 10−12 m2 (1 darcy). Moreover, the contact margin of rapakivi intrusions also include fractured and hydrothermally altered rocks that have significantly high porosity and permeability. In detail, rocks dominated by fractures typically have little porosity (<4%) and exhibit extremely high permeability (~10−12 m2) only at low confining pressures, which sharply decreases to ~10−19 m2 as the confining pressure surpasses 20–30 MPa (corresponding to depths around 700–1000 m). From our dataset, only fractures linked to mineral dissolution have the potential to sustain permeability above 10−16 m2 at 50 MPa confining pressure (simulating depths of ~2 km). Conversely, rocks that underwent cataclasis and hydrothermal alteration exhibit comparatively milder permeability reductions, maintaining high values even when subjected to high confining pressures of 50 MPa. Throughout the entire dataset, a consistent observation emerges: mafic minerals are commonly substituted by chlorite and epidote, suggesting hydrothermal alteration processes occurring at relatively high temperatures (200–300 °C).

Implications for geothermal exploration

Exploring deep geothermal resources in crystalline settings offers a promising solution for direct space heating, industrial applications, and electricity generation. However, the typically low porosity and low permeability of crystalline rocks remain a key obstacle in deep geothermal exploration. The identification of hydrothermally altered rocks as potential deep geothermal reservoirs could mark a substantial shift in geothermal exploration within crystalline regions, broadening target prospects beyond the conventional focus on volcanic and rifting areas. Brecciation, cataclasis, fracturing, and mineral dissolution collectively contribute to the creation of exceptional reservoir properties, which have been widely overlooked in deep and ancient (over a billion years) crystalline settings. Our results hold paramount importance for identifying highly productive permeable zones within crystalline settings and also to the advancement of Enhanced Geothermal Systems that could prioritize the creation of more intricate fracture networks through thermal and chemical stimulation.

How to cite: Heap, M., Bischoff, A., Luoto, T., Reuschlé, T., Vuoriainen, S., Spitz, M., and Leon-Stackow, M.: A comprehensive petrophysical databank of crystalline reservoirs for assessing deep geothermal exploration targets in Finland and abroad, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4423, https://doi.org/10.5194/egusphere-egu24-4423, 2024.

EGU24-6192 | ECS | Posters on site | ERE5.2

Structural, petrophysical, and geophysical characterization of a fault zone in southern Finland – application for subsurface fluid flow in granitic settings 

Jon Engström, Alan Bischoff, Evgenii Kortunov, Mira Markovaara-Koivisto, Nikolas Ovaskainen, Nicklas Nordbäck, and Markku Paananen

Southern Finland crystalline basement was formed and modified during the 1.9–1.8 Ga Svecofennian orogeny, which constitutes a portion of the Fennoscandian Shield. The bedrock comprises supracrustal and early to late-orogenic igneous rocks of mafic to felsic compositions and is characterized by an overall high metamorphic grade associated with high-T and low-P conditions. The bedrock was subjected to multiple tectonic events of distributed deformation, first during a compressional stage, then followed by an extensional stage and finally  a transpressional stage.

Hence, the Kopparnäs study site in southern Finland has been subjected to several stages of ductile and brittle deformation. The site has been studied by the Geological Survey of Finland for several years, with special research emphasize on a subvertical E–W orientated multi-core fault zone that intersects granites, amphibolites, and migmatites. A drillhole cuts through this fault zone at 100 m depth. This drillhole has beed studied using downhole instrumentation, such as optical and acoustic imaging and diverse geophysical surveys (fullwave sonic, magnetic susceptibility, gamma density, natural gamma radiation, drillhole caliper and various electrical loggings). In addition, a comprehensive study of the drill core enables detailed geological and petrophysical characterization of the fault architecture, including recognition of fractures, alteration zones, and mineralization across the fault and its host rocks. These studies together with fluid flow measurements with a packer system, enable us to define subsurface properties for this fault zone.

The initial results suggest that faulting strongly impacts the petrophysical characteristics of the rock, typically increasing porosity and reducing bulk density. This change is most likely related to the fracturing at the site being often associated with mineral alteration and dissolution. These events altered and deformed the multiple fault cores in distinctively manner, affecting the subsurface fluid flow which can be observed in fluid chemical composition differences.

These studies are part of the FLOP project (FLOw Pathways within faults and associated fracture systems in crystalline bedrock) and the Deep-HEAT geothermal energy project. 

How to cite: Engström, J., Bischoff, A., Kortunov, E., Markovaara-Koivisto, M., Ovaskainen, N., Nordbäck, N., and Paananen, M.: Structural, petrophysical, and geophysical characterization of a fault zone in southern Finland – application for subsurface fluid flow in granitic settings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6192, https://doi.org/10.5194/egusphere-egu24-6192, 2024.

EGU24-7157 | ECS | Orals | ERE5.2

Reconstructing the geothermal reservoir model and estimating the structural permeability variation in the metamorphic terrane in Ruisui, Taiwan 

Yung-Ching Huang, Jian-Cheng Lee, Gong-Ruei Ho, Chih-Wen Chiang, Yi-Chia Lu, Sheng-Rong Song, Chih-Hao Yang, Chi-Hsuan Chen, and Yue-Gau Chen Chen

    This study identifies the key geothermal features in the metamorphic terrane within the Yuli belt (a metamorphic mélange) in Ruisui, eastern Taiwan, including fault-related pathways for hot fluids, cap rocks, and naturally fractured reservoirs, and builds a structural permeability distribution model. A preliminary geothermal reservoir model is created for a depth of 3 km, by integrating geological field analysis, magnetotelluric (MT) surveys, hot spring geochemistry, and data from 3 exploration wells. The low resistivity zones shown in MT results are beneath a unit of amphibole-albite schist, containing numerous ultra-mafic blocks at different sizes. We tentatively interpret the four MT low-resistivity zones as four possible reservoirs, which are associated with high-density jointed and faulted quartz-mica schists, underneath cap rocks of amphibole-albite schists, which reveal poor development of joints. The geochemical analysis of hot spring water indicates a high concentration of sodium ions, potentially originating from the amphibole-albite schist. We also observe surface exposures where water up to 50-60oC flows up through NW-SE trending sub-vertical faults with the downhole temperature up to 200oC at a depth of 0.9km.

    To determine whether the NW-SE vertical fault zones are suitable for open structures, which appear to be the major geothermal up-flows, we measure the orientation of faults and 3 sets of joints, most of which are sub-vertical in the field. The principal stress orientations are adopted as σ1 vertical, σ2 N120oE, and σ3 N30oE, by combining GPS observation, focal mechanisms of shallow earthquakes, and fault slickenlines measured in exposures. We conduct fault-slip inversion and obtain the stress ratio phi=0.51. Utilizing the Mohr-Coulomb failure criterion coupled with selected parameters, such as in-situ principal stresses, fluid pressures, and rock mechanical properties, our model indicates that steeply-dipping NW-SE trending (N120o-130Eo) joints and faults are mechanically prone to open as fluid infiltrating or injecting during thermal events.

    We furthermore measured the fracture length and density at the aforementioned hot spring exposure where 50-60oC hot fluid flows out from an NW-SE trending sub-vertical fault. The measuring result shows that the density of the fractures (or joints) decreases away from the fault core, thus we anticipate the joints tend to form on the microfractures created by the fault, which explains an increase of the permeability toward the fault. As for estimating the structural permeability along the NW-SE fault and open joints, the fracture aperture is calculated using linear elastic fracture mechanics, and then the permeability is estimated by using the cubic law for fluid flow in rock fractures. By doing so we obtain the structural permeability in the NW-SE fault zone, which exponentially decreases away from the fault core, and the permeability value ranges from 10-10 to 10-13 m2 at a distance of 10 m.

How to cite: Huang, Y.-C., Lee, J.-C., Ho, G.-R., Chiang, C.-W., Lu, Y.-C., Song, S.-R., Yang, C.-H., Chen, C.-H., and Chen, Y.-G. C.: Reconstructing the geothermal reservoir model and estimating the structural permeability variation in the metamorphic terrane in Ruisui, Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7157, https://doi.org/10.5194/egusphere-egu24-7157, 2024.

EGU24-8226 | ECS | Orals | ERE5.2

Fault core structure affects fault slip during fluid injection: insights from laboratory friction experiments 

Stefano Aretusini, Chiara Cornelio, Giuseppe Volpe, Giacomo Pozzi, Elena Spagnuolo, and Massimo Cocco

Natural faults when subjected to stimulation by fluid injection may result in slip acceleration because pore pressure (Pf) increases in the rock volumes inside and surrounding the fault zone leading to reduction of effective normal stress (σn’). Slip mode ranges from aseismic creep to seismic ruptures defining a spectrum of fault-slip behavior. Fault stimulation experiments will be conducted in the Bedretto Underground Laboratory for Geosciences and Geoenergies (BULGG, Switzerland) to understand fault reactivation processes on a target well-identified fault zone, fully instrumented to monitor deformation and seismicity during both fluid injection and fault reactivation. This is envisioned in the ERC-Synergy FEAR (Fault Activation and Earthquake Rupture) project. In BULGG, the target fault zone has both a sub-centimetric fault core containing fault gouge and granite asperities in contact and other fractures in the surrounding rock volume.  Therefore, it becomes important to define the frictional properties and slip mode of both gouges and bare rock surfaces taking advantage of a laboratory controlled experimental environment.

Fault stimulation by increasing Pf was simulated in laboratory following an injection protocol suitable for the BULGG fluid stimulation. Experiments were performed on the target fault gouge and on bare rock surfaces made of nearby Rotondo Granite. We employed a rotary shear apparatus (SHIVA) allowing the fluid injection under a controlled shear stress. First, we imposed the stresses measured at depth in the underground laboratory, halved due to apparatus limitations: 7.5 MPa σn’, 7.5 MPa confining pressure and 2.5 MPa Pf. Second, we imposed a slip rate of 10-5 m/s for 0.01 m to have a reference texture. Third, we applied a shear stress so that an equivalent slip tendency of 0.35 (equal to the one measured in the target fault) is achieved (ca. 2.7 MPa) keeping it constant. We then increased stepwise the pore fluid pressure by 0.1 MPa every 150 s. After fault slip initiation, the maximum allowed slip velocity was 0.1 m/s. Between each of the experimental stages, permeability and transmissivity were measured with the gradient or Pf oscillations methods.

We show that reactivation occurs at lower Pf in bare rock surfaces (4.7 MPa) with respect to MC fault gouge (6.5 MPa), suggesting that the effective coefficient of friction, the ratio of shear stress and σn’, is larger in gouge (0.58) than in bare rock surfaces (0.49). Moreover, upon the application of last Pf step, reactivation is slower in fault gouge (150 s delay) with respect to bare rock surfaces (10 s delay), consistently with the lower hydraulic transmissivity measured for target fault gouge with respect to bare rock surfaces (i.e., 10-19 vs 10-17 m3). Our experiments also show that creep and dilatancy precede reactivation in fault gouge, whereas reactivation is sudden and not preceded by dilatancy in bare rock surfaces.

We suggest that well-oriented and smooth bare rock surfaces might be easily reactivated similarly to what observed for fault gouge during fluid stimulation. Our data and observations will contribute to shed light on the mechanics of faults and induced earthquakes by fluid stimulation experiments.

How to cite: Aretusini, S., Cornelio, C., Volpe, G., Pozzi, G., Spagnuolo, E., and Cocco, M.: Fault core structure affects fault slip during fluid injection: insights from laboratory friction experiments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8226, https://doi.org/10.5194/egusphere-egu24-8226, 2024.

EGU24-8619 | ECS | Orals | ERE5.2

Hydraulic Stimulation Experiments in a Decimeter-scale True Triaxial Compressive Apparatus 

Julian Osten, Mohammadreza Jalali, Alexander Cadmus, Leonie Welsing, Tom Schaber, Paul Cook, Yves Guglielmi, Raul Fuentes, and Florian Amann

Geothermal energy is considered a sustainable energy source for the transition to a carbon-neutral economy. In Central Europe, sufficiently hot source rocks are buried deep underground and comprise tight crystalline basement formations. To extract their thermal energy, hydraulic stimulation is used to create efficient heat exchangers in the context of Enhanced Geothermal Systems (EGS). Successful geothermal reservoir initiation requires a broad understanding of the hydro-mechanical coupling in fractured rock masses. For this reason, a decimeter-scale true-triaxial setup has been developed to conduct injection-driven shear tests under various stress conditions.

To gain a deeper insight into the hydro-mechanical processes involved in hydraulic stimulation, a true triaxial compressive apparatus at the decimeter scale is employed. The experimental setup consists of 30 x 30 x 45 cm cuboidal granite specimens, each containing an oblique saw-cut laboratory fracture with different surface properties. The fracture is crossed by two boreholes equipped with packers to isolate a fracture interval. Fluid injection into the isolated intervals follows the typical HTPF (hydraulic testing of pre-existing fractures) scheme, including stepwise pressure increases and decreases. Stress boundary conditions are introduced by three sets of oil-filled flatjacks, contained within a steel frame which allows a more realistic and accurate replication of the stress conditions experienced by geological formations during hydraulic stimulation experiments. Stresses for individual tests are manipulated from hydrostatic to strike-slip conditions to test for different end member states of slip tendency. Fracture and rock deformations are recorded by 16 linear variable differential transformer (LVDT) sensors mounted externally along the edges of the specimen, volume changes in the flatjacks and a newly developed borehole deformation probe (mini-SIMFIP).

How to cite: Osten, J., Jalali, M., Cadmus, A., Welsing, L., Schaber, T., Cook, P., Guglielmi, Y., Fuentes, R., and Amann, F.: Hydraulic Stimulation Experiments in a Decimeter-scale True Triaxial Compressive Apparatus, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8619, https://doi.org/10.5194/egusphere-egu24-8619, 2024.

EGU24-9336 | ECS | Orals | ERE5.2

Fractal diffusion analyses of periodic pumping tests 

Victoria Alegria Jimenez Martinez, Yan Cheng, and Jörg Renner

We investigated the usefulness of the fractal diffusion equation, also known as generalized radial flow (GRF) equation, to characterize hydraulic properties and flow dimensions of the subsurface. Unlike other methods for deriving hydraulic properties that require selecting the flow dimension, analyses based on the GRF equation in principle constrain both, flow dimension and hydraulic properties. We utilized the GFR equation to analyze periodic pumping tests carried out in boreholes penetrating gneiss rocks in the research mine Reiche Zeche, Freiberg, Germany. These tests involved one injection borehole, where flow rate and injection pressure were recorded, and four monitoring boreholes, where pressure responses were monitored. Phase-shifts and amplitude ratios were derived through interference analysis, involving a comparison of the periodic signals of injection and monitoring pressure, as well as injectivity analysis, consisting of a comparison of the periodic flow rate and injection pressure. The pumping tests were conducted at three distinct intervals within the injection borehole, isolated by a double-packer probe and selected based on the characteristics of the fractures intersecting the borehole.  One interval contained a natural fracture zone characterized by a high fracture density with a high mean aperture. The others were previously hydraulically stimulated. While one of them had a single pre-existing fracture, the other was entirely intact before the stimulation that led to an induced fracture with feather geometry, as typical for a borehole that does not follow a principal stress axis. Several observations suggest that the gneiss volume is hydraulically heterogeneous: a) the hydraulic properties and flow dimensions vary with pumping period; b) estimated diffusivity values and flow dimensions differ for interference and injectivity analyses; c) discernible differences in diffusivity values and flow dimensions along diverse hydraulic paths, as determined by interference analysis. Furthermore, pressure dependence in hydraulic properties and flow dimensions are observed for all intervals. The hydraulic response of the fault-zone interval exhibits a greater sensitivity to variations in mean pumping pressure than the two stimulated intervals.

How to cite: Jimenez Martinez, V. A., Cheng, Y., and Renner, J.: Fractal diffusion analyses of periodic pumping tests, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9336, https://doi.org/10.5194/egusphere-egu24-9336, 2024.

EGU24-9736 | ECS | Posters on site | ERE5.2

Characterization and 3D geometrical modelling of a complex fault zone for earthquake rupture experiments 

Alberto Ceccato, Peter Achtziger-Zupančič, Giacomo Pozzi, Alexis Shakas, Alba Simona Zappone, Daniel Escallon, Marian Hetrich, Mohammadreza Jalali, Xiaodong Ma, Men-Andrin Meier, Julian Osten, Florian Amann, Massimo Cocco, Domenico Giardini, and Stefan Wiemer

Fault zone geological and geometrical complexities are prime parameters playing a fundamental role in controlling the characteristics of both natural and induced seismicity. In the Bedretto tunnel (Switzerland), the Fault Activation and Earthquake Rupture (FEAR) project aims at triggering a Mw = 1 seismic event through fluid injection and stimulation of a natural fault zone situated in a large-scale (> 106 m3) fractured granite reservoir. The limited exposure of the fault zone in the tunnel, however, restricts the possibility to constrain in detail the geometrical and geological characteristics of the experimental target. Therefore, in order to constrain the geological and geometrical characteristics of the target fault zone, we have integrated structural analyses, borehole and core logging, and borehole ground penetrating radar (GPR).

Preliminary field investigations in the tunnel allowed to identify the complex fault structure characteristics, fault rock properties, and slip tendency in the current stress field of the selected fault zone. These results were compared to the structural observations obtained from field surveys and remote sensing, constraining the slip history, and lateral extent of the set of natural fault zones occurring on the surface above the Bedretto tunnel. Indeed, the lateral extent of the selected fault has been confirmed through the logging (optical/acoustic televiewer, fracture intensity, fracture typology) of exploration boreholes and the analyses of the related cores. The comparison between the geological characteristics of fault zones in the cores and the characteristics of the selected fault zone exposed in the tunnel allowed to confirm the occurrence of the same typology of fault zone further away from the exposure in the tunnel. In addition, GPR logging of the exploratory boreholes provided fundamental insights on the lateral continuity of the identified fault zones on the tunnel wall, as well as those identified in the borehole/core logging.

All geological and geometrical information have been integrated into a preliminary 3D geometrical model (in Leapfrog Geo), representing the overall geometry of the selected fault zone. This preliminary geometrical model has been validated against synthetic GPR profiles, computed through GPR forward modelling along the exploration boreholes.

The integrated results define the selected fault zone as a 3-7 m wide zone of higher density (up to 5/m), of variably oriented secondary fractures, and bounded by two main slip surfaces. The slip surfaces are irregularly decorated by phyllosilicate-rich gouge patches, filling the roughness of the fault surface. The lateral extension of each discrete fracture does not exceed 30 m in length, but the overall lateral continuity of the fault zone exceeds several hundreds of meters.

The presented integrated characterization approach allowed us to constrain a geologically-sound, first-order 3D geometrical model of a complex natural fault zone, validated against geophysical forward modelling. These preliminary results have fundamental implications for the expected experimental planning and outcomes, modelling and injection strategies, project logistics, as well as the design and deployment of the monitoring network around the stimulated fault zone.

How to cite: Ceccato, A., Achtziger-Zupančič, P., Pozzi, G., Shakas, A., Zappone, A. S., Escallon, D., Hetrich, M., Jalali, M., Ma, X., Meier, M.-A., Osten, J., Amann, F., Cocco, M., Giardini, D., and Wiemer, S.: Characterization and 3D geometrical modelling of a complex fault zone for earthquake rupture experiments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9736, https://doi.org/10.5194/egusphere-egu24-9736, 2024.

EGU24-10618 | ECS | Posters on site | ERE5.2

Systematic multi-stage hydraulic stimulation experiments in a hectometer-scale fractured rock volume at the Bedretto Underground Laboratory, Switzerland 

Kai Bröker, Xiaodong Ma, Nima Gholizadeh Doonechaly, Antonio Pio Rinaldi, Anne Obermann, Martina Rosskopf, Marian Hertrich, and Domenico Giardini and the BedrettoLab Team

Interest in engineered geothermal systems (EGS) has grown in the last decade due to their recognition as a low-emission, renewable energy source. EGS reservoirs with sufficiently high temperatures are located at depths of several kilometers, where the permeability of the crystalline basement rocks is insufficient for geothermal energy extraction. Permeability enhancement is accomplished through hydraulic stimulation, either by hydraulic shearing of natural fractures or shear zones, or through hydraulic fracturing of intact rock. The Bedretto Underground Laboratory for Geosciences and Geoenergies (BedrettoLab) in Switzerland serves as an in situ test-bed where hectometer-scale hydraulic stimulation experiments are conducted to better understand the seismo-hydromechanical response of fractured crystalline rock masses (Ma et al. 2022).

The geothermal testbed of the BedrettoLab is located in a 100 m long enlarged section of the Bedretto tunnel in the Swiss Central Alps, with an overburden of more than 1000 m of granite. Several characterization, monitoring, and two stimulation boreholes were drilled. One of the stimulation boreholes (referred to as ST1) is 400 m long, 45°-dipping, and was equipped with a multi-packer system that partitions the borehole into 15 intervals.

In this work, we present the structural and seismo-hydromechanical characterization of eight stimulation intervals closely observed using a dense monitoring network (see Plenkers et al. 2023 for the detailed network layout). We injected relatively small fluid volumes (0.35–14 m3) following a standardized injection protocol to compare the response of the targeted geological structures in each interval. Depending on the transmissivity of the interval, the stimulation was conducted pressure- or flow rate-controlled with several steps at constant pressure/flow rate. Despite the similarly oriented structures in each interval, the observed seismo-hydromechanical behavior is complex and heterogeneous. The detected seismicity follows multiple steeply-dipping and NE-SW striking planes (Obermann et al. 2024), which coincides with the direction of known pre-existing fault structures obtained from the geological characterization. In most intervals, a clear bilinear behavior on the pressure vs. flow rate plot marks a strong increase in injectivity above a certain reactivation pressure. Analysis of these reactivation pressures in comparison with the stress field, fracture and seismic cloud orientations implies that the stimulation mechanism is hydraulic shearing of the fractures rather than elastic opening (also known as hydraulic jacking).

References:

Ma, X., Hertrich, M., Amann, F., Bröker, K., Gholizadeh Doonechaly, N., et al. (2022). Multi-disciplinary characterizations of the BedrettoLab -- a new underground geoscience research facility. Solid Earth, 13(2), 301–322. https://doi.org/10.5194/se-13-301-2022

Obermann, A., et al. (2024). Picoseismic response of hectometer-scale fracture systems to stimulation with cm-scale resolution under the Swiss Alps, in the Bedretto Underground laboratory. In preparation for JGR: Solid Earth.

Plenkers, K., Reinicke, A., Obermann, A., Gholizadeh Doonechaly, N., Krietsch, H., et al. (2023). Multi-Disciplinary Monitoring Networks for Mesoscale Underground Experiments: Advances in the Bedretto Reservoir Project. Sensors, 23(6), 3315. https://doi.org/10.3390/s23063315

How to cite: Bröker, K., Ma, X., Gholizadeh Doonechaly, N., Rinaldi, A. P., Obermann, A., Rosskopf, M., Hertrich, M., and Giardini, D. and the BedrettoLab Team: Systematic multi-stage hydraulic stimulation experiments in a hectometer-scale fractured rock volume at the Bedretto Underground Laboratory, Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10618, https://doi.org/10.5194/egusphere-egu24-10618, 2024.

EGU24-11634 | ECS | Posters on site | ERE5.2

Fault Nucleation and Reactivation in Displaced Fault Systems: An Experimental Study 

Milad Naderloo, Jan Dirk Jansen, and Auke Barnhoorn

Understanding fault slip nucleation within the reservoir interval and its propagation beyond the reservoir is essential. Analytical and numerical studies have shown that, depending on the type of operation (injection/depletion), fault slip can nucleate at external or inner corners along the displaced fault system, driven by positive peak shear stresses. In the case of depletion, slip patches gradually start at the inner corners and grow towards the inner part of the reservoir, merging with further depletion. Conversely, injection or increased pore pressure leads to slip patches at external corners, potentially propagating beyond the reservoir into the overburden and underburden. We conducted triaxial experiments on small-scale (mm scale) cylindrical samples containing an entirely displaced vertical fault to investigate fault reactivation and slip nucleation in such settings. Two types of stress paths, monotonic and cyclic, were applied to examine the effects of stress patterns on slip nucleation. For this purpose, we utilized strain gauges to measure differential compaction along the displaced fault directly on the small-scale samples. Direct measurements with a strain gauge network adjacent to the displaced fault system during the monotonic test revealed that differential compaction intensifies from the top of the sample towards the internal corner at the center of the fault where different layers are juxtaposed vertically, indicating a variation in the stress field surrounding the fault plane. Furthermore, results from the cyclic test showed that the differential compaction increases with an increasing number of cycles. Our direct measurements near the displaced fault plane confirm/match the anomalies and peaks in stress observed in previous numerical and analytical studies.

How to cite: Naderloo, M., Jansen, J. D., and Barnhoorn, A.: Fault Nucleation and Reactivation in Displaced Fault Systems: An Experimental Study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11634, https://doi.org/10.5194/egusphere-egu24-11634, 2024.

EGU24-11723 | Orals | ERE5.2

Spatio-temporal evolution of permeability during quasi-static fault growth in granite 

Nicolas Brantut, Frans Aben, and Ado Farsi

In tight crystalline basement rocks such as granite, faults are known to be substantially more hydraulically conductive than the rock matrix. However, most of our knowledge of rock permeability in the laboratory and in the field relies on indirect inference, static measurements, or before/after datasets, and the spatio-temporal evolution of the permeability field during faulting remains unknown. Specifically, we would like to determine at which stage of the faulting process does permeability change most, and the degree of permeability heterogeneity along shear faults.

We conducted a series of triaxial deformation experiments in initially intact Westerly granite, where faulting was stabilised by monitoring the acoustic emission rate. At many stages from pre- to post-failure states, we paused deformation and imposed macroscopic fluid flow to characterise the overall permeability of the material. In addition, we measured the pore pressure distribution in the sample, and estimated apparent permeability at different locations along the fault, from the intact ligaments to damaged regions. We monitored the propagation of the macroscopic shear fault by locating acoustic emissions.

We find that average permeability increases dramatically (by around 3 orders of magnitude) near the peak stress, where the fault (as seen by acoustic emission locations) is not yet through-going. Post-peak evolution shows a more gradual increase in overall permeability, with local heterogeneities remaining along the fault, primarily controlled by small-scale fault geometry and the existence of undamaged regions as imaged by acoustic emission locations.

We conclude that permeability change and fluid flow focussing occurs at very early stages of faulting, and do not require substantial slip. Our results highlight the key role of fault geometry in the fine-scale permeability structure of basement rocks.

 

How to cite: Brantut, N., Aben, F., and Farsi, A.: Spatio-temporal evolution of permeability during quasi-static fault growth in granite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11723, https://doi.org/10.5194/egusphere-egu24-11723, 2024.

EGU24-11990 | Posters on site | ERE5.2

Microstructural Characterization of Fault Rocks from the Groningen Gas Field 

Ernst Willingshofer, Job Arts, Dallyn Rodrigues, Fadi Nader, Martyn Drury, Liviu Matenco, and Andre Niemeijer

Human activities in the subsurface such as geothermal energy production, CO2- and hydrogen storage, and gas extraction can affect the regional stress field and lead to induced seismicity. Gas production from the Groningen gas field in the northeast of the Netherlands has led to more than 300 shallow earthquakes with local magnitudes ML > 1.5 and up to a maximum magnitude of ML 3.6, resulting in substantial damage to buildings. Recent earthquake localization studies show that seismicity dominantly occurs on complex normal fault systems, at the depth of the Permian (Rotliegend) reservoir. These faults were formed during multiple tectonic phases from the Late Paleozoic to Early Cenozoic and may comprise breccias, cataclasites, fault gouges and clay smears. The fault strength and slip behaviour are controlled by its composition and microstructural state (porosity, grain size and shape, and presence of foliation within the fault core). Fluid-rock interactions and diagenetic processes during and after fault activity may have altered these characteristics and, hence, the strength and slip behaviour of the fault. Knowledge on the state and composition is thus required to reliably predict the maximum stress drop and seismic energy release upon fault reactivation. However, such knowledge is still lacking at present day.

With this study, we aim at characterizing the microstructures of fault gouges in the Groningen faults. We assess the mineralogy, porosity, and grain size distribution of natural samples from faulted core samples derived from the Groningen gas field. Well-log data is presented to show the representativeness of these samples in the larger context of the gas field. The observations on natural microstructures are then used to define simplified geometrical representations or scenarios that can be used as input for microphysical models. Microstructural characterization involves optical microscopy for quantitative petrography of both bulk rock and selected regions of interest (ROI) within the fault zone. Scanning Electron Microscopy (SEM) with Backscattered Electron (BSE), Cathodoluminescence (CL), and Energy-Dispersive X-ray Spectroscopy (EDX) is employed to analyse porosity, grain size, shape, and mineralogy of faulted regions.

Preliminary results show that the compositions of fault rocks differ from the host rock and that along-fault variability in mineralogy, cementation, and grain size are important to consider. We distinguish between four main types of fault gouges in the Groningen Rotliegend, based on their microstructural characteristics: (1) gouges consisting of quartz and feldspar grains embedded in a very fine clay matrix, (2) very fine-grained quartz-rich gouges, (3) quartz-cemented gouges, and (4) anhydrite-cemented gouges. We expect that induced fault movement in the first two gouges occurs by reactivation of the earlier produced fault gouges. Since quartz and anhydrite cementation is concentrated in the faults, reactivation of the latter two presumably occurs by cataclastic processes and gouge formation from the adjacent bulk rock rather than the cemented gouge. This suggests that a well constrained fault diagenetic history is required to infer which components of the fault material governs its frictional behaviour and hence the related seismic hazards. 

How to cite: Willingshofer, E., Arts, J., Rodrigues, D., Nader, F., Drury, M., Matenco, L., and Niemeijer, A.: Microstructural Characterization of Fault Rocks from the Groningen Gas Field, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11990, https://doi.org/10.5194/egusphere-egu24-11990, 2024.

EGU24-13098 | Orals | ERE5.2

Heat Sensitive Epoxy Foam for Permeability Alteration in Fractured Geothermal Fields  

Dani Or, Rishi Parashar, Ying Yang, Manish Bishwokarma, and Satish Karra

Geothermal energy plays a growing role in the transition to renewable and carbon free energy sources. A challenge for many geothermal fields is how to enhance water-rock heat exchange either by creation of new fractures, or by blocking short-circuiting large conduits. Here we report a novel approach for blocking large conduits (faults and large fractures) using heat sensitive epoxy resin foam designed to be transported as discrete resin droplets to specific regions that are then activated (foamed and cure) in-situ at targeted temperatures. In contrast with alternative methods for reducing geothermal rock permeability such as silicate gels or heat responsive polymer microbeads targeting small aperture fractures < 0.1 mm, the epoxy foam can reduce the permeability of fractures with apertures up to several millimeters. Results from laboratory 2-D glass fracture model provide insights by visualizing the transport phase and subsequent temperature-sensitive foaming and curing transformations with associated flow pathway blocking. Modeling results for transport and foaming in simple fracture networks considering rheological properties and foaming (volume expansion) behavior will be presented. On going activities of rheological resin characterization; tuning of the foaming-curing to different temperature ranges; and consideration of resin dispersion using small droplets for enhanced transport will be discussed.  

How to cite: Or, D., Parashar, R., Yang, Y., Bishwokarma, M., and Karra, S.: Heat Sensitive Epoxy Foam for Permeability Alteration in Fractured Geothermal Fields , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13098, https://doi.org/10.5194/egusphere-egu24-13098, 2024.

EGU24-15749 | ECS | Posters on site | ERE5.2

Exploring the Hydro-Mechanical Behavior of Fractures Utilizing the mini-SIMFIP Probe 

Tom Schaber, Julian Osten, Mohammadreza Jalali, Alexander Cadmus, Leonie Welsing, Paul Cook, Yves Guglielmi, Raul Fuentes, and Florian Amann

The SIMFIP (Step-rate Injection Method for Fracture In-situ Properties) probe is a downhole displacement tool designed to measure injection-driven fracture displacement in an isolated borehole interval in three dimensions. The resulting displacement and interval pressure data can be used to estimate fracture characteristics such as fracture stiffnesses, strength and hydraulic properties from borehole measurements. SIMFIP results have also been successfully implemented in a stress inversion routine that allows the calculation of the full stress tensor from a single measurement.

As part of the SPINE (Stress Profiling IN Enhanced geothermal systems) project, a laboratory-scale deformation tool, the mini-SIMFIP probe has been developed. The probe, with a diameter of 20 mm and a length of 65 mm, can be installed in laboratory to study the 3D deformation of intact rock and fractures in different type of rocks. Preliminary tests were conducted in a decimeter-scale true triaxial test apparatus containing a cuboid granite sample with an oblique saw-cut laboratory fracture. Two boreholes crossing the fracture can be isolated and equipped with the mini-SIMFIP probe. Fluid injection into the isolated interval opens the fracture or induces hydraulic shearing under anisotropic stress conditions. The resulting dataset can be used to quantify measurement uncertainties associated with the field SIMFIP protocol, to benchmark stress inversion protocols against known stress boundary conditions, and gain better insight into hydro-mechanically coupled processes.

How to cite: Schaber, T., Osten, J., Jalali, M., Cadmus, A., Welsing, L., Cook, P., Guglielmi, Y., Fuentes, R., and Amann, F.: Exploring the Hydro-Mechanical Behavior of Fractures Utilizing the mini-SIMFIP Probe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15749, https://doi.org/10.5194/egusphere-egu24-15749, 2024.

Bentheim sandstone is regarded as a conventional georeservoir rock even at great depth, due to its mineral composition, homogeneity, micro- and macrostructure. Therefore it has been extensively tested for a variety of applications to understand its physical and mechanical properties under changing environmental conditions.

A recent study has shown how the simultaneous change of pressure, temperature and pore pressure, therefore recreating environmental conditions at selected depths, affects the evolution of permeability at depths, both when the rock is buried and when the rock is exhumed. The interaction between those variables has a complex effect on the permeability of Bentheim Sandstone, which could not have been identified by assessing individually the role of a variable. These results show that the permeability of such rock could be overestimated with classical studies and highlight the importance of investigating rock mechanical and hydraulic properties at georeservoir conditions. These experiments have been performed on intact samples.

However, rocks at depth contain fractures and faults, which may alter the interconnectivity of the pore space, hence the permeability of the rock itself. The deformation and failure of Bentheim Sandstone at high strain resulted in permeability loss due to the formation of comminuted material and grain crushing which lowered the pore space interconnectivity. No fractured sample has been tested under simultaneously changing environmental conditions.

To fill this gap, we replicate the experimental procedure used to test intact samples of Bentheim sandstone, both under simultaneously changing conditions and under a sequential variation of different variables, after the sample has been brought to failure. Our goal is to understand the importance of fractures on the permeability evolution at different simulated depths.

How to cite: Fazio, M. and Sauter, M.:  Permeability evolution of a fractured, porous and permeable sandstone at simulated georeservoir conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18390, https://doi.org/10.5194/egusphere-egu24-18390, 2024.

EGU24-18458 | ECS | Posters on site | ERE5.2

Variations in fracture distribution across Northern Bavaria – Towards large-scale geothermal fracture models 

Ruaridh Smith, Rahul Prabhakaran, Fabian Jakob, and Daniel Koehn

Natural faults and fractures form a critical component of fluid flow in low permeable reservoirs such as tight carbonates for a wide variety of applications including geothermal energy extraction. Fractured systems often control permeability in these reservoirs at the first order where properties of these networks are defined by fracture orientation, intensity, aperture, and connectivity. Accurately quantifying these network properties is vital in generating representations of the fracture networks at reservoir depth.

In regions with limited subsurface data (borehole and seismic), field data and outcrop analogues become an important source for characterising the fracture networks for modelling reservoirs at depth. Outcrops can be used to define several properties of the networks and information on the variation in the fracture distribution across defined areas.

The Franconian Basin is a major tectonic structure in Northern Bavaria containing Mesozoic sediments up to 3500m thick. It is a relatively under-researched region where limited subsurface data is available in comparison to the south in the Molasse Basin where geothermal exploration and production is well established with extensive subsurface datasets widely distributed. Increased geothermal gradients have been identified in Northern Bavaria, including surrounding the major urban areas presenting an opportunity to improve the understanding of the geothermal potential of the region. Several of the identified reservoir units in this region are primarily composed of low permeable carbonates where faults and fractures control primary reservoir flow. These units are also present as outcrop analogues in the Franconian Alb which can be utilised for surface fracture characterisation.

We present results analysing the variations in the fault and fracture systems from across the region captured from 1D measurements and 2D and 3D imaging of quarry and cave outcrops. Using these results, stochastic fracture models of the parts of the region can be generated, providing realisations of the fracture networks which can contribute to assessing the permeability and geothermal potential of the reservoirs in Northern Bavaria.

How to cite: Smith, R., Prabhakaran, R., Jakob, F., and Koehn, D.: Variations in fracture distribution across Northern Bavaria – Towards large-scale geothermal fracture models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18458, https://doi.org/10.5194/egusphere-egu24-18458, 2024.

EGU24-19263 | ECS | Orals | ERE5.2

The evolution of crack transmissivity under normal and shear stress before and after slip 

Lining Yang, Julian Mecklenburgh, and Ernest Rutter

Understanding the flow of fluids in the subsurface is of vital importance to geo-energy exploitation and disposal of waste fluids. In most situations, individual cracks can be more effective for fluid transport than fluids flowing through the porous matrix of the rock. The enhancement of a single crack in a low permeable rock can be over 1000 times. However, for both porous matrix flow and crack flow, the bulk permeability and crack transmissivity are all affected by the stress state in the lithosphere.

This study aims to investigate the influence of the Terzaghi effective normal and shear stress on the transmissivity of cleavage cracks under upper crustal conditions. Penrhyn slate was selected as samples for the experimental study because of its low porosity (<1%), permeability and slaty cleavage. The matrix permeability of Penrhyn slate is very low, ranging from 10-20 to 10-22 m2 when the effective pressure is in the range of 10 to 53 MPa measured by the oscillating pore pressure method (OPPM). The crack transmissivity ranged from 10-18 to 10-23 m3 when the effective pressure changed from 10 to 280 MPa. The experimental results show that the evolution of crack transmissivity of a single fracture under several cycles of pressurization and depressurization is similar to the trend found in permeability. The first application of the normal stress on fracture surfaces always produces a nonrecoverable loss in crack transmissivity. In the subsequent pressurization and depressurization, partially recoverable variations in transmissivity were observed, suggesting a linear elastic behaviour of crack closure. The highest peak effective pressure attained in the stress history affects the extent of subsequent recoverable crack transmissivity. When the fracture surface is subjected to a new higher peak stress, the crack transmissivity will no longer recover to its former low level but to a lower level, indicating a permanent transmissivity loss. Thus, the transmissivity has a memory of the previous maximum stress the fractured rock was subjected to.

The influence of shear stress on crack transmissivity was studied in Solnhofen limestone and Carrara marble samples with saw-cut ground smooth fractures and compared with the rough cleaved fractures of Penrhyn slate. The influence of shear stress was studied in two situations: (a) the stable (no-slip) condition at shear stress less than needed to promote slip on fracture (b) at shear stresses high enough to yield slip on the fractures. In situation (a), the cyclic increase and decrease of shear stress led to a continuous decrease in crack transmissivity. The magnitudes of this decrease in crack transmissivity decrease with more cycling. The transmissivity tended to decrease to a lowest value eventually but this lowest value can be regenerated by slip on the fracture. In situation (b), a single slip can decrease crack transmissivity. The decrease in crack transmissivity can be attributed to the formation and smearing of frictional wear products or gouges. Under the progressive compaction, there exists a lowest level of crack transmissivity which is independent of the normal stress.

How to cite: Yang, L., Mecklenburgh, J., and Rutter, E.: The evolution of crack transmissivity under normal and shear stress before and after slip, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19263, https://doi.org/10.5194/egusphere-egu24-19263, 2024.

EGU24-19710 | Orals | ERE5.2

Evolution of Microcracks in Damaged Natural Salt: Insights from 4D imaging 

Yuntao Ji, Christopher Spiers, Suzanne Hangx, Hans de Bresser, and Martyn Drury

Rocksalt formations are critical candidates for storing natural gas, hydrogen, compressed air energy, and radioactive waste. While pure, undisturbed rock salt deposits exhibit low porosity and impermeability when buried deeply, excavation leads to near-field microcracking and dilatancy in the salt, increasing porosity and permeability. Over time, the connectivity of brine- or water-vapor-filled microcrack networks in deformation-damaged salt is expected to decrease, partly due to dissolution-precipitation healing. In this study, we employ 4D (time-resolved 3D) microtomography to investigate the long-term evolution of dilated grain boundary and microcrack networks developed in deformation-damaged natural salt through brine-assisted processes. Our findings reveal substantial microstructural modification and healing occurring over periods ranging from days to a few months. Cracks and dilated grain boundaries undergo crystallographic faceting, necking, and migration, effectively "recrystallizing" the material and resulting in increased tortuosity and decreased connectivity of the crack network. Understanding the complex interplay between microcracking, healing, and permeability changes in deformation-damaged rock salt is of utmost importance for optimizing storage and disposal applications in geomechanics and physical chemistry. Our research contributes valuable insights to this field and informs the sustainable development and management of rock salt formations for diverse energy storage and waste management needs.

How to cite: Ji, Y., Spiers, C., Hangx, S., de Bresser, H., and Drury, M.: Evolution of Microcracks in Damaged Natural Salt: Insights from 4D imaging, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19710, https://doi.org/10.5194/egusphere-egu24-19710, 2024.

EGU24-20381 | ECS | Posters on site | ERE5.2

Physical and mechanical characterization of veined rocks: Implications to a porphyry model 

Franco Robbiano, Luis Felipe Orellana, and Marie Violay

The brittle-ductile transition is an important mechanical shift within the Earth's lithosphere and, as a crucial interface between ascending hot magma and colder host rock, plays a fundamental role in fluid migration within hydrothermal systems. Traditionally assumed to occur at temperatures between 350 °C and 400 °C, recent studies challenge this assumption, revealing a temperature transition range dependent on minerals. Experimental and numerical investigations highlight significant variability, ranging from 260 °C in wet quartz to 700 °C for dry orthopyroxene within homogeneous mineral compositions.

This study delves into the complexities of this rheological barrier in the El Teniente Mafic Complex in Chile (currently a copper mine and formerly a hydrothermal system at the BDT), unraveling its impact on the migration of magmatic fluids. Building on previous research suggesting a self-sustaining mechanism that facilitates fluid movement over the brittle-ductile transition through overpressure-permeability waves and the formation of a dense, multi-episode vein network, our focus is on understanding deformation mechanisms and the localization of deformation and permeability at the BDT. Heat transfer models propose a dual paradigm of conduction and convection, adding to the complexity.

To address these challenges, we conducted a comprehensive series of physical and mechanical measurements on 34 cylindrical samples from the El Teniente Mafic Complex. This included analyses of density, porosity, elastic wave characteristics, and electrical conductivity under variable water conductivities. Elastic wave measurements were performed using 2.25 MHz transducers on both dry and saturated samples. Permeabilities were determined by the pulse decay technique for compact rocks, complemented by triaxial tests and local strain measurement using strain gauges, along with acoustic emission measurements on dry samples subjected to confinements similar to those near the mine.

Our results highlight consistently low porosity (below 1%) in the samples, with electrical conductivity, permeability, and strength controlled by veins. Particularly, at lower salinities, the metallic particle content and the orientation of the vein with respect to the loading axis significantly influence electrical conductivity and phase. At higher water conductivities, behavior is governed by connected porosity. Furthermore, favorably oriented veins emerge as crucial controllers of both permeability and mechanical resistance.

These observations align with a convection heat flow model in a porphyry system, providing significant insights into the complex interaction between rock and vein properties. The study uniquely focuses on fossil high enthalpy systems, shedding light on their complex behavior. Additionally, the article discusses constraints on model variables, fostering a comprehensive understanding of the brittle-ductile transition in magmatic-hydrothermal systems.

How to cite: Robbiano, F., Orellana, L. F., and Violay, M.: Physical and mechanical characterization of veined rocks: Implications to a porphyry model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20381, https://doi.org/10.5194/egusphere-egu24-20381, 2024.

EGU24-20658 | ECS | Posters on site | ERE5.2

Impact of Capillary Number, Fluid Viscosity Ratio, and Fracture Closure on Two-Phase Flow Regimes in Geological Fractures: An Experimental Study 

Amin Rezaei, Francesco Gomez, Oshri Borgman, Insa Neuweiler, and Yves Meheust

Accurately predicting fluid-fluid interface displacement in fractured reservoirs is paramount for optimizing subsurface operations, particularly in the context of enhanced oil recovery and geological carbon sequestration (GCS). However, a comprehensive understanding of two-phase flow behavior in fractures, including the impact of fracture closure, fluid viscosity ratio, and capillary number, is yet to be achieved. To address this challenge, we have developed an analog experimental setup to investigate the intricate relationship between fracture surface roughness and fluid-fluid interface displacement. Our experimental setup features a transparent fracture flow cell with self-affine rough-walled surfaces that are matched to each other above a chosen length scale (denoted below as the correlation length) and a precisely controlled mean aperture. Realistic synthetic fracture geometries were generated numerically. They are characterized by their Hurst exponent, fracture closure, and correlation length. High-speed imaging captures the dynamic spatial distribution of fluid phases within the fracture plane during drainage processes in a given fracture geometry. The mean aperture can be varied between experiments for a given geometry of the fracture walls. We investigate a comprehensive range of capillary numbers, spanning both viscous and capillary-dominated regimes, vary viscosity ratios, and characterize the resulting displacement regimes. Our results reveal a profound impact of fracture closure and correlation length on trapping efficacy, particularly in the capillary-dominated regime. These findings can be interpreted in terms of residual trapping of CO2 during GCS in fractured reservoirs.

How to cite: Rezaei, A., Gomez, F., Borgman, O., Neuweiler, I., and Meheust, Y.: Impact of Capillary Number, Fluid Viscosity Ratio, and Fracture Closure on Two-Phase Flow Regimes in Geological Fractures: An Experimental Study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20658, https://doi.org/10.5194/egusphere-egu24-20658, 2024.

EGU24-22156 | ECS | Posters on site | ERE5.2

FracAbility: A python toolbox for survival analysis in fractured rock systems 

Gabriele Benedetti, Stefano Casiraghi, Andrea Bistacchi, and Daniela Bertacchi

When analysing fractured rock outcrops, the fracture network's topology and length statistics are of fundamental importance. Past literature focused on adopting a non-parametric approach for the unbiased estimation of fracture length data mean, and with some additional steps, the variance of a population. However, technology improved, and necessities shifted. Now it is possible to quickly obtain dense length datasets with thousands of measurements and the emergence of stochastic DFNs increased the demand for parametric solutions to correctly fit several types of distributions. These conditions highlighted an absence of works on these topics. Of particular interest is the right censoring bias effect of the interpretational boundary on the fracture length statistics. We tackle this problem by applying survival analysis techniques, a branch of statistics that includes methods for modelling time to event data and correctly estimating the model’s parameters with data affected by censoring. Synthetic testing has been carried out, showing a reliable estimate of the distribution parameters with up to 80% of the total measurements being censored. Moreover, it is shown that the correction is independent from the orientation of the fracture set or boundary geometry. We propose FracAbility, a new open-source Python package capable to both analyse the topology of fracture networks and, by using the latest SciPy version, correctly fit different parametrical distributions on length data with right censored measurements. The library and the proposed approach have been applied to real world data, successfully correcting length distributions affected by censoring.

How to cite: Benedetti, G., Casiraghi, S., Bistacchi, A., and Bertacchi, D.: FracAbility: A python toolbox for survival analysis in fractured rock systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22156, https://doi.org/10.5194/egusphere-egu24-22156, 2024.

When the oilfield is in the middle and late stage of intensive waterflood development, waterflood development is likely to cause fault activation and bring about the development risk of injection-production contradiction in well groups and low injection-production correspondence rate. Therefore, it is necessary to identify and evaluate the fault sealing of low-grade faults. At present, the fault sealing is mostly high-grade faults in the exploration stage and mostly stays in the semi-quantitative evaluation method. Therefore, this paper provides a set of integrated thinking of fault interpretation and fault sealing quantitative evaluation in production and development stage. Firstly, the fault is delineated by well-seismic integrated method, and the possible fault breakpoint is identified from changes of strata thickness in the well. Secondly, high-frequency seismic data are obtained by frequency division, and faults are identified on the basis of fault breakpoint data by two-dimensional seismic section. Then, various three-dimensional seismic attributes such as ant tracking and variance (edge method) are extracted, and the combination of plane and section interpretation is used to strengthen fault characterization and recognition in three-dimensional space. The basic characteristics of faults are described well by the above methods. Then, the fault sealing property is qualitatively evaluated from the aspects of fault nature, fault inclination, fault distance and burial depth, and the conventional fault sealing property is quantitatively analyzed from shale gouge ratio method, lithologic juxtaposition method and the normal pressure on the fault plane from lateral and vertical aspects. Finally, the fuzzy comprehensive discrimination method is used to comprehensively evaluate the fault sealing property based on the above three parameters of the analysis results. The method is applied to ZB area with complex structure and developed fault, and the threshold of fault opening or sealing is determined by the comprehensive evaluation index of fault sealing in ZB area of Bohai Bay Basin. The results of low-grade fault sealing identified in the early stage are judged and applied to the development and production practice. The dynamic and static data such as tracer response relationship, injection-production response relationship and oil properties on both sides of the fault are used to verify the method. The results show that the method is in good agreement with the dynamic and static data .It is suitable for the fault sealing evaluation of  ZB area,and can better guide the later waterflood development, which is of great significance for the recovery of remaining oil .

How to cite: Cheng, C. and Zhang, X.: Application of a fault identification and fault sealing evaluation method in production and development stage in ZB area of Bohai Bay Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1, https://doi.org/10.5194/egusphere-egu24-1, 2024.

In a fracture-cavity carbonate reservoir, a myriad of irregular cavities is distributed, serving as primary reservoirs for oil storage. Simultaneously, fractures play a pivotal role by establishing efficient pathways for the movement of oil and water between these cavities, thereby facilitating fluid migration. Consequently, gaining a comprehensive understanding of the connectivity between the cavities and fractures within the reservoir is crucial for optimizing and implementing efficient development strategies. However, the fluid flow behavior within the cavities and fractures, under the influence of multiple coupled fields, remains highly complex, and previous studies have yet to fully elucidate this intricate phenomenon. This study addresses the knowledge gap by employing numerical simulations to investigate the interactions between cavities and fractures, as well as the fluid flow patterns within them. The study utilizes porous media permeability based on Darcy's law to characterize fluid flow within the matrix, fracture flow described by the Brinkman equation for fluid movement within fractures, and free flow based on Navier-Stokes equations to depict fluid motion within solution cavities. Building upon this foundation, and applying the theory of multi-field coupling, different flow models were tailored for the cavities, fractures, and rock matrix, taking into account key factors such as fracture angle, stress state, and fracture connectivity. The simulation results provide valuable insights, from which we draw the following conclusions: (1) When the maximum principal stress direction is perpendicular to the fracture direction, the fractures experience compression perpendicular to their normal direction, leading to a tendency of closure and consequently reducing the efficiency of oil migration within the fractures. Conversely, when the maximum principal stress is parallel to the fracture direction, the fractures undergo tension along their normal direction, causing them to open up and thereby enhancing the efficiency of oil migration within the fractures. (2) With an increasing fracture angle, the angle between the fractures and the principal stress increases. As a result, the fractures experience an increased compressive stress component, leading to a decrease in their conductivity and reducing the efficiency of fluid migration between different cavities. (3) Increasing the tortuosity of the fractures reduces the flowability of the fluid within the fractures. The larger the tortuosity of the fractures, the poorer the conduit capacity of the fractures for the oil phase, resulting in a decrease in the efficiency of oil migration between different cavities.

How to cite: Wang, H. and Wu, Z.: Research on the Multi-Modal Flow Mechanism of Oil and Water in Fractured Carbonate Reservoirs under Multiple Coupling Effects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-101, https://doi.org/10.5194/egusphere-egu24-101, 2024.

EGU24-272 | ECS | Posters on site | ERE5.3

Numerical Modeling of Fluid and Heat Flow in the Southern North Sea 

Deniz Orta and Doğa Düşünür Doğan

Understanding fluid flow and temperature distribution in geothermal potential fields is of utmost importance as it provides valuable insights into the mechanisms governing these fields. Extensive research has been conducted worldwide, employing geological, geophysical, and hydrothermal modeling techniques, to investigate geothermal fluid and heat flow patterns. This paper focuses on studying a geothermal potential area located in the southern North Sea to analyze fluid and heat flow characteristics and their temporal variations in the region. A comprehensive approach was adopted, combining geophysical data with modeling results. The marine seismic data obtained from the southern North Sea were utilized to identify faults, fluid flow features, and geological units, forming the basis of a hydrogeophysical model. To investigate this phenomenon further, numerical modeling was performed using ANSYS FLUENT, a finite volume-based Computational Fluid Dynamics (CFD) software. The model incorporated the geometry of the studied field derived from the seismic section, along with the physical and hydraulic properties of the medium. Thermal and physical rock properties were obtained from previous research. As the numerical simulation progresses over time, the expected results include the temperature distribution/fluid flow patterns and the factors controlling them. The models will provide novel perspectives on the geothermal potential in the southern North Sea, offering insights into the fluid and heat flow characteristics of the region.

How to cite: Orta, D. and Düşünür Doğan, D.: Numerical Modeling of Fluid and Heat Flow in the Southern North Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-272, https://doi.org/10.5194/egusphere-egu24-272, 2024.

EGU24-273 | ECS | Posters on site | ERE5.3

Numerical Modeling of Fluid Flow in Gas Hydrate Bearing Sediments in Black Sea 

Bahar Güvem and Doğa Düşünür Doğan

It is important to understand the stability, behavior and environmental effects of hydrates because gas hydrate reserves are being evaluated as potential energy sources of the future. Many studies have been conducted support that the Black Sea has suitable pressure and temperature conditions for gas hydrate formation, and it has been proven that there are signs of gas hydrate in marine sediments.  In this article, it is aimed to evaluate the effects gas hydrate-derived free gas (methane) found in Black Sea marine sediments and the chemical reaction of hydrate with groundwater over time by using a numerical modeling program. ANSYS Fluent, which is a computational fluid dynamics (CFD) program and works on the principle of finite volumes and whose suitability has been confirmed in past studies in fields with gas hydrate, was used as a numerical modeling program. For the purpose of numerical modeling, a previously collected and published depth-converted seismic reflection profile was selected as a reference model. This reference model includes the Bottom Simulating Reflector (BSR) seismic signature, which serves as a possible indicator of the presence of gas hydrates. Additionally, it incorporates a fault-like irregularity to examine its impact on the model. Through the simulations, the study will be investigated the fluid flow dynamics and the interaction between hydrate-derived free gas and groundwater within the model. The research will be focused on examining the temporal changes in the mass ratios of methane (CH4) as well as the byproducts of this chemical reaction, namely carbon dioxide (CO2) and hydrogen (H2). In addition to the time-depend changes mentioned, the study also involves modeling the impact of the fault, which created discontinuities within the system, on the reactants and byproducts. The movement of these substances within the model, their accumulation within the sediment, and their dispersion or migration away from the model is presented. Simulation results show that dissolution time of methane and production time of carbon dioxide and hydrogen is strongly affected by the presence of faults, sea bottom morphology and initial rate of methane within marine sediments.

How to cite: Güvem, B. and Düşünür Doğan, D.: Numerical Modeling of Fluid Flow in Gas Hydrate Bearing Sediments in Black Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-273, https://doi.org/10.5194/egusphere-egu24-273, 2024.

EGU24-2193 | ECS | Orals | ERE5.3

A Matter of Geometry: Predicting Single Fracture Permeability by Evaluating Imaging Methods and Persistent Homology Analysis   

Marco Fuchs, Anna Suzuki, Togo Hasumi, Sina Hale, Larissa Blesch, Kathrin Menberg, Gabriel C. Rau, and Philipp Blum

Fractures play a significant role in various geoscientific applications, such as nuclear waste disposal, geothermal energy, and hydrocarbon extraction. Understanding the governing hydraulic characteristics of fractures and their impact on flow processes is crucial for the success of these applications. Among the many parameters that affect fracture behavior, permeability stands out as one of the most critical. Several methods have been developed to investigate fracture permeability, including flow-through experiments and numerical hydraulic simulations. However, it is important to note that the geometry of a fracture greatly influences its permeability. This study focuses on examining different workflows to directly estimate the permeability of a single fracture based on its geometry. In the first step to achieve this, we apply and evaluate three fracture surface imaging methods: (1) handheld laser scanner (HLS), (2) mounted laser scanner (MLS), and (3) Structure from Motion (SfM). We conducted our study using a bedding joint in Flechtinger sandstone as the fracture sample. After capturing the fracture geometries using these imaging methods, we perform numerical flow simulations to estimate hydraulic apertures. Our findings reveal that due to limited resolution and accuracy, the HLS is not suitable for use in numerical flow simulations. However, MLS and SfM result in hydraulic apertures that exceed experimental air permeameter measurements (81 ± 1 µm). The hydraulic apertures obtained using MLS and SfM are 163 µm and 207 µm, respectively. To bridge the discrepancy between simulations and measurements, we stepwise increase the contact area, resulting in hydraulic apertures of 85 µm at 5 % contact area and 83 µm at 7 % contact area for MLS and SfM, respectively. In the second step, we utilize the topological persistent homology (PH) method to calculate permeability directly from the fracture geometry derived from MLS, eliminating the need for laboratory experiments or numerical simulations. We create three different datasets of the same fracture, varying in spatial resolution (200 µm, 100 µm, and 50 µm). The results from the PH analysis demonstrate hydraulic apertures ranging from 73 µm to 92 µm, which align closely with the air permeameter measurements. Notably, the accuracy of fracture permeability prediction improves with higher resolution. In summary, this study presents an effective workflow that enables the direct estimation of fracture permeability based on the geometry of a sandstone fracture. By utilizing different imaging methods and topological analysis, we provide valuable insights into understanding and predicting fracture permeability.

How to cite: Fuchs, M., Suzuki, A., Hasumi, T., Hale, S., Blesch, L., Menberg, K., Rau, G. C., and Blum, P.: A Matter of Geometry: Predicting Single Fracture Permeability by Evaluating Imaging Methods and Persistent Homology Analysis  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2193, https://doi.org/10.5194/egusphere-egu24-2193, 2024.

EGU24-2439 | Orals | ERE5.3

Remote hydraulic fracturing at weak interfaces 

Keita Yoshioka and Tao You

Hydraulic fracturing is a reservoir stimulation technique that has been applied since the 1950s and is one of the most effective ways to enhance well productivity. At the same time, hydraulic fracturing can induce seismicity or result in the loss of containment of subsurface fluids due to the high injection pressure applied during its operation, leading some projects to eventual shut-down. To mitigate such adverse impacts, an alternative approach known as hydro shearing has been promoted for some enhanced geothermal system projects, wherein the injection pressure is kept at a low level, aiming to stimulate pre-existing networks of fractures by shearing. However, the practical effectiveness of hydro shearing is yet to be proven. In this talk, we propose another alternative stimulation approach using a low-viscosity fluid. We demonstrate that with low-viscosity fluid injection, we can fracture discontinuous interfaces such as grain boundaries or natural fractures without initiating fractures at the injection point. Our results indicate the possibility of engineering reservoir stimulation operations without applying high injection pressure.

How to cite: Yoshioka, K. and You, T.: Remote hydraulic fracturing at weak interfaces, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2439, https://doi.org/10.5194/egusphere-egu24-2439, 2024.

EGU24-7550 | ECS | Orals | ERE5.3

Structural and flow modelling of bedrock fractures - a software perspective 

Nikolas Ovaskainen, Nicklas Nordbäck, Jon Engström, and Kaisa Nikkilä

Discontinuities of the bedrock, i.e. fractures, form the main pathways for fluid flow in crystalline rocks. For modelling purposes, fracture data can be gathered from e.g. bedrock outcrops and drillcores. Remote digitization of bedrock outcrops results in mostly two-dimensional fracture data while structural measurements in-situ and from drillcores results in three-dimensional data. The nowadays common digitized two-dimensional fracture trace data can be analysed for geometric (e.g. orientation and length) and topological properties (e.g. connectivity). For these purposes, specialized tools exist such as FracPaq (Healy et al., 2017), NetworkGT (Nyberg et al., 2018) and fractopo (Ovaskainen, 2023).

For three-dimensional fracture data analysis, the options become more sparse because as the data gains complexity through the addition of a dimension, so does the software required for analysis. This is especially the case for software that, rather than analysing fracture data, (also) generates it such as with discrete fracture network (DFN) modelling. DFN-modelling is required when fluid flow, reactive flow, geothermal flow, or contaminant transport properties of the fracture network need to be assessed at a scale larger than it is feasible to collect fracture data. Due to the added complexity, the available software for these purposes is varied and require specialized knowledge to use them effectively. In hydrocarbon exploration, geothermal exploitation and nuclear waste disposal, software such as FracMan (WSP trademark) is used for DFN-modelling and subsequent flow modelling. Although free and open-source options for DFN-modelling exist, they often lack user-friendly interfaces and lack the necessary manpower for further development outside of research purposes. 

In FLOP (FLOw Pathways within faults and associated fracture systems in crystalline bedrock) -project we gather knowledge of the available free and open-source software for three-dimensional fracture data analysis and modelling. We integrate the found solutions with macro- and microscale fracture data from outcrops and X-ray CT-imaging, respectively, to investigate flow channeling. We also apply the more mature tools available for two-dimensional fracture trace analysis, such as fractopo (Ovaskainen, 2023), to characterize varied sampling locations where flow properties of field analogues will be studied. 

The FLOP-project is funded by SAFER2028, a Finnish research programme on nuclear energy research, and the Geological Survey of Finland. The project is conducted in collaboration with the Deep-HEAT-Flows geothermal energy project. 

References

Healy, D., Rizzo, R.E., Cornwell, D.G., Farrell, N.J.C., Watkins, H., Timms, N.E., Gomez-Rivas, E., Smith, M., 2017. FracPaQ: A MATLAB™ toolbox for the quantification of fracture patterns. Journal of Structural Geology 95, 1–16. https://doi.org/10.1016/j.jsg.2016.12.003

Nyberg, B., Nixon, C.W., Sanderson, D.J., 2018. NetworkGT: A GIS tool for geometric and topological analysis of two-dimensional fracture networks. Geosphere 14, 1618–1634. https://doi.org/10.1130/GES01595.1

Ovaskainen, N., 2023. fractopo: A Python package for fracture network analysis. JOSS 8, 5300. https://doi.org/10.21105/joss.05300

How to cite: Ovaskainen, N., Nordbäck, N., Engström, J., and Nikkilä, K.: Structural and flow modelling of bedrock fractures - a software perspective, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7550, https://doi.org/10.5194/egusphere-egu24-7550, 2024.

The heat transfer capability of any geothermal system is an essential characteristic deciding about its productivity, lifetime, and sustainability. Common attempts assuming thermal equilibrium between hot rock and injected fluid have shown to be a poor proxy for the thermal field in the subsurface. More detailed models at the laboratory scale based on explicit heat transfer between phases provide much better estimates but require a priori information concerning fracture geometry and network connectivity that is commonly not available at field scale applications.

Based on these single and discrete fracture models, this work presents an effective heat transfer model upscaled for fracture networks. Using a realistic parameter set including fracture orientation, fracture density, and the permeability distribution, the developed approach determines the heat transfer coefficient and heat transfer area to be subsequently used in a coupled thermo-hydraulic model to simulate the evolution of the temperature field. The heat transfer coefficient is derived from a semi-empirical approach using the dimensionless Nusselt, Prandtl, and Reynolds numbers, and based on over 240 experiments. The heat transfer area is analytically derived from geometrical constraints. This approach achieves good agreement with single fracture experiments as well as with an analytical solution for an equally spaced fracture network. Its full capabilities are demonstrated with a complex three-dimensional simulation of a doublet system in a heterogeneous fracture network including anisotropy.

How to cite: Heinze, T.: Estimating the heat transfer capability of fractured geothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8373, https://doi.org/10.5194/egusphere-egu24-8373, 2024.

EGU24-11408 | Orals | ERE5.3

The impact of fractures on the Biot and Skempton coefficients of fractured rocks   

Silvia De Simone, Caroline Darcel, Hossein Kasani, Diego Mas Ivars, and Philippe Davy

The Hydro-Mechanical (HM) behavior of fluid-saturated porous materials is crucial in determining the response of the subsurface to natural processes, such as glaciation, and to engineering applications, such as construction/excavation, reservoir impoundments, geo-energy extraction, and deep geological disposal of used nuclear fuel. Two fundamental coefficients, i.e., the Biot coefficient and the Skempton coefficient, define the contribution of the fluid in subsurface media to maintain the mechanical equilibrium against perturbations in stress and pore fluid pressure. Despite the central importance of these two coefficients, which may broadly range between 0 and 1, their estimation is often oversimplified in most scientific and engineering studies that treat large-scale saturated problems by assuming a uniform geological material, with the coefficients estimated experimentally at the laboratory sample-scale or analytically through expressions valid for isotropic homogeneous materials.

In this work, we analyze the impact of fractures on the HM behavior of fractured rocks by looking at the equivalent Biot coefficient and Skempton coefficient. We adopt a recently defined framework in which the equivalent coefficients are estimated from the properties of both the porous intact rock and the discrete fracture network (DFN), including fracture size, orientation and mechanical properties. We extend this theory to incorporate more realistic assumptions on fractures, such as size-dependent and stress-dependent fracture properties. This setting allows us to explore the range of variability of the two equivalent coefficients with respect to the stochastic distribution of fracture size and orientation in the rock, and with respect to depth and stress faulting regime. We show that the coefficients are larger if 1) the network is placed in shallow rocks (i.e., low stress regime), 2) the network is populated by a few large fractures rather than by many small fractures, and 3) the fractures are oriented parallel to the in-situ maximum principal stress and normal to the applied stress.

How to cite: De Simone, S., Darcel, C., Kasani, H., Mas Ivars, D., and Davy, P.: The impact of fractures on the Biot and Skempton coefficients of fractured rocks  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11408, https://doi.org/10.5194/egusphere-egu24-11408, 2024.

Offshore crystalline basement volumes forming fractured reservoirs contain hydrocarbons within hydraulically conductive fracture networks. These networks, in places occurring at sub-seismic scales, may develop from geologically long and complex polyphase deformation histories. If, on the one hand, characterising fracture-related permeability and connectivity is vital in assessing hydrocarbon play prospectivity, on the other it is challenging due to the inaccessibility of the off-shore volumes and the small average size and intricacy of transmissive fractures. Indeed, approaches relying on deep wells and regional seismic data usually lack the spatial, temporal, and genetic resolution to properly resolve the sub-seismic fracture networks that guarantee the secondary permeability of those rock volumes. Correlative studies on onshore analogues, may therefore be of great assistance. Leveraging the improved resolution advantages of a series of geologically well-constrained onshore analogues, this study incorporates multi-scalar lineament trace maps, outcrop, and drill hole orientation data from Smøla Island in Central Norway to identify a number of systematic fracture sets, associated fracture size distributions, and fracture frequency and trace intensities. Crucially, this study also incorporates both deterministic cross-cutting/termination information, and absolute K-Ar age constraints from fault gouges on Smøla on the age of formation of the main faults and fracture sets. These fracture and temporal input variables were used to generate several ‘grown’ discrete fracture network (DFN) models. By generating fractures in a series of timesteps, these models produce a more realistic simulation of natural fracture patterns, including important fracture intersections and terminations. The models represent stochastic fracture network realisations which 'back-strip’ from the present to the Mid-Cretaceous, Late Triassic-Early Jurassic, and the Late Carboniferous/Early Permian. Based on each of these time-stage models, probabilistic outputs of 3D fracture network connectivity, and permeability tensor orientations using assumed reservoir values were produced. Our findings suggest a temporal shift in the principal permeability (K) tensor orientations during the extension of the Mid-Norwegian margin, opening of the North Atlantic, and Norwegian Sea basin development. A comparative analysis with known Norwegian Sea reservoir charging and fluid migration events suggests possible key basement-hosted tectonic structural geometries that have had permeability values through time that are of interest for hydrocarbon accumulation and potential geofluid storage.

How to cite: Hodge, M., Cottrell, M., Knies, J., and Viola, G.: Temporal evolution of fracture connectivity and permeability in crystalline basement volumes: an applied stochastic modelling approach for the Mid-Norwegian margin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13003, https://doi.org/10.5194/egusphere-egu24-13003, 2024.

Fractures such as joints and faults are prevalent discontinuity features in the Earth’s crust, forming hierarchical networks in the subsurface and controlling the bulk behaviour of geological media. They play an important role in various multiphysical processes such as stress transfer, pressure diffusion, heat transport, earthquake generation, wave scattering, and chemical dissolution, which are crucial for many geoenergy applications ranging from geothermal energy exploitation and critical mineral extraction to nuclear waste disposal and underground hydrogen storage. Thus, it is of central importance to advance our capability of realistically representing these ubiquitous discontinuity features and further accurately modelling the associated seismo-thermo-hydro-mechanical processes. Over the past years, I have established a powerful fractured media simulation platform based on the discrete fracture network concept to simulate coupled multiphysical processes in fractured rocks. The model can explicitly represent the distribution of a large number of fractures in both 2D and 3D space as well as accurately compute their multiphysical responses/interactions over both space and time domains. No a priori assumption about the representative elementary volume is needed, rendering this approach as an appropriate tool to study hierarchical fractured rocks that may have no characteristic length scale. Using this modelling paradigm, diverse macroscopic phenomena in fractured media can be captured as emergent properties physically arising from the collective behaviour of numerous existing/growing fractures and interacting rock blocks. This multiphysics modelling framework can serve as a useful tool to bridge experimentally-established constitutive relationships of fracture/rock samples at the laboratory scale to phenomenologically-observed macroscopic properties of fractured geological formations at the site scale. A series of case studies are presented, where high-fidelity multiphysics simulations are combined with high-quality laboratory measurements and/or high-resolution field observations to address different geoenergy-related problems. The research findings and insights obtained have important implications for understanding and predicting the behaviour of fractured rocks for safe and sustainable geoenergy development.

How to cite: Lei, Q.: Discrete fracture network modelling of multiphysics processes in fractured media for geoenergy applications, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13320, https://doi.org/10.5194/egusphere-egu24-13320, 2024.

Fractured and karstified carbonates often serve as major aquifers and hydrocarbon reservoirs. Water-rock interactions within variable aperture fractures can lead to dissolution of fracture surfaces and local alteration of fracture apertures, potentially transforming the transport properties of fractures over time. Numerical modeling offers a valuable tool for comprehending the spatial and temporal evolution of karst reservoirs. This work aims to present a comprehensive model to reveal percolation characteristic and dissolution process of stochastic primary fracture systems in carbonate formation. Based on the embedded discrete fracture model, a multi-scale modeling approach is proposed to describe fracture networks with different topologies and various apertures. This model is verified against preexisting numerical models. Simulation results shows that the mechanisms of flow focusing and reactive infiltration instabilities determines fracture dissolutional propagation. Patterns of local dissolution-induced alterations related to fracture permeability, hydraulic conductivity and extensive dissolution appear in fracture tips and intersections.

How to cite: Liu, H., Dong, C., and Lin, C.: Flow Channeling, Dissolutional Growth, and Preferential Flow of Fractures in Karst formation: Insights from Reactive Transport Modeling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13719, https://doi.org/10.5194/egusphere-egu24-13719, 2024.

This study presents a comprehensive numerical framework for simulating the evolution of fractures in mining sites characterized by fluid-saturated media during excavation. The proposed model integrates phase field fracture mechanics with a coupled solution approach, employing the finite volume method to solve fluid flow equations and the finite element method for geomechanical analysis. The complex interaction between fluid flow and geomechanics is crucial in understanding and predicting fracture propagation in mining environments. The phase field approach allows for a continuous representation of fractures, capturing their initiation, propagation, and coalescence throughout the excavation process. The model incorporates the influence of fluid saturation on fracture behaviour, providing a more realistic representation of the dynamic interplay between the geological medium and the excavated space. The fluid flow equations are discretized using the finite volume method, considering the poroelastic nature of the rock mass. This approach enables the accurate simulation of fluid movement within the saturated medium, considering the changes induced by excavation activities. Simultaneously, the geomechanics equation is solved using the finite element method, accounting for the stress distribution and strain evolution in response to excavation-induced changes. To validate the efficacy of our FEM code, the model is initially subjected to a single fracture scenario, treated as a notch, and benchmarked against published experimental and numerical results for an elastic medium subjected to compressive loads. The successful validation underscores the robustness of our approach in capturing mixed-mode fracturing phenomena in mining environments. The coupling of fluid flow and geomechanics allows for a thorough investigation of the impact of excavation on fracture initiation and propagation in mining environments. The proposed model provides valuable insights into the complex mechanics of fracture evolution in fluid-saturated mining sites, aiding in the development of strategies for optimizing excavation processes and ensuring the safety and stability of mining operations. The integration of finite volume and finite element methods enhances the accuracy and efficiency of the simulation, making the model a powerful tool for researchers and practitioners in the field of mining engineering.

How to cite: Kar, S. and Chaudhuri, A.: Multi-Physics Modeling of Phase Field Fracture in Fluid-Saturated Mining Environments during Excavation., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14515, https://doi.org/10.5194/egusphere-egu24-14515, 2024.

This study is focused on the performance evaluation of composite laminated shells when the crack initiates and propagates longitudinally or circumferentially. For this purpose, two numerical composite shell models are considered. One is the equivalent single layer model, and the other is discrete-layer model. Both models are based on the p-convergent higher-order theory or called as the functionally refined model. The second model is mainly adopted and compared with the first model to predict the stress intensity factor in the vicinity of a crack tip not only before patch repair, but also after patch repair. The patch reinforcement effect has been analyzed with respect to various experimental parameters in terms of material type of patch, patch size, patch thickness, adhesive shear modulus, adhesive thickness, etc. The present model has a subprarmetric concept that considers linear mapping of geometry fields on a cylindrical coordinate, and hierarchical approximating functions are based on one- and two-dimensional integrals of Legendre polynomials, allowing accurate simulation of three-dimensional behavior. In assumed displacement field, stain-displacement relations and 3-D constitutive equations of one random layer are obtained by product of 1-D and 2-D higher-order shape functions. Thus it allows independent implementation of increasing p-level, order of shape function, for in-plane and out-of-plane displacement. In the proposed elements, the integrals of Legendre polynomials and Gauss-Lobatto technique are applied to interpolate displacement fields and to implement numerical integration. The sensitivity test has been carried out to show the robustness of present p-convergent higher-order element associated with severe element distortions, very high aspect ratios of elements, and very large radius-to-thickness ratios of shells. For verification of the proposed model, some benchmark laminated shell problems have been solved as compared to the numerical results obtained by the conventional h-convergent finite element method and other p-convergent analyses that used the Lagrange type polynomials as a shape function. Numerical results show that the proposed model is capable of prediction in-plane stresses around the crack tip as well as interlaminar stresses at the interface between shell layers.

How to cite: Yang, S.: Functionally refined model for cracked cylindrical shells repaired with laminated composite materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15300, https://doi.org/10.5194/egusphere-egu24-15300, 2024.

EGU24-15525 | ECS | Orals | ERE5.3 | Highlight | ERE Division Outstanding Early Career Scientist Award Lecture

Fault Lines to Frontlines: Geomechanical Challenges of Sustainable Energy Transition 

Roberto Emanuele Rizzo, Derek Boswell Keir, Andreas Busch, Nathaniel Forbes Inskip, David Healy, Snorri Gudbrandsson, Luca De Siena, and Paola Vannucchi

The transition to sustainable energy systems introduces a complex landscape, wherein geothermal energy and carbon dioxide storage (CCS) play critical roles. These activities target geological formations that are always faulted and fractured. As the focus intensifies on alternative energy systems for decarbonisation, understanding these faulted rocks in the subsurface gains great importance. Fault and fracture systems can act not only as conduits for fluid flow but they can also be zones of mechanical weakness that may respond dynamically to fluid pressure changes due to natural geological processes or anthropogenic activities, such as CCS or geothermal extraction. This dual role of fault and fracture systems as pathways for fluid flow and as potential triggers for mechanical failure makes their study a cornerstone of sustainable subsurface resource management. The challenge lies in accurately characterising the permeability of these systems and estimating their mechanical behaviour under changing stress conditions. This is vital for ensuring the integrity and efficacy of operations like CCS and geothermal energy extraction, where even slight variations in fluid pressure can have significant implications. For instance, experiences from the fluid injection experiment for an enhanced geothermal system in Basel, Switzerland, and the In Salah CCS pilot site in Algeria highlight how minor changes in pore fluid pressures (as little as 10 MPa) can induce leakage and/or seismic activities. We highlight selected case studies from both active and prospective CCS and geothermal sites (in Svalbard and Mid-Ethiopian Ridge, respectively). These examples illustrate methodologies in fault stability analysis and geomechanical characterization, shedding light on the relationship between fluid flow, stress alterations, and rock mechanics in faulted and fractured formations. By coupling empirical data with modelling techniques, we present strategies to mitigate risks and enhance the efficiency of subsurface decarbonisation efforts.

How to cite: Rizzo, R. E., Keir, D. B., Busch, A., Forbes Inskip, N., Healy, D., Gudbrandsson, S., De Siena, L., and Vannucchi, P.: Fault Lines to Frontlines: Geomechanical Challenges of Sustainable Energy Transition, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15525, https://doi.org/10.5194/egusphere-egu24-15525, 2024.

EGU24-16775 | Posters on site | ERE5.3

Coupling of thermo-hydro-mechanical modeling with seismicity modeling in a faulted geothermal reservoir 

Rahim Habibi, Thomas Ulrich, Alice-Agnes Gabriel, Joachim Wasserman, and Emmanuel Gaucher

Geothermal energy is seen as an effective factor in the global energy transition for the supply of heat and electricity. To produce large amount of geothermal energy, reservoirs with high temperature, usually deep, should be targeted. At depth, aquifers are not common and most of the geothermal fluid circulates within a fault network. Hence, such geothermal reservoirs can be exploited using production and injection wells drilled in faulted geological formations. The operation of such faulted geothermal system generates seismic events, which sometimes can be felt by humans. The events result from the complicated thermo-hydro-mechanical and chemical response of the system against operational and geo-reservoir parameters, e.g. production flow rate, fault permeability, stress field, etc. Consequently, numerical simulation of the operation of faulted geothermal systems can provide operators and the public with information on the likely occurrence of seismic events during and after the lifetime of the powerplant. Considering seismic event as an additional response of the system to the THMC response in the numerical model makes the simulation more complicated and involves more parameters.

In this study, to solve the simulation complexity, we propose to couple two finite element numerical codes, one based on the MOOSE framework and SeisSol. The former is used to simulate the THM response of the reservoir (chemical effects are not taken into account) to site operations. The latter is applied to simulate the dynamic seismic response of the fault(s). For the coupling, a bash script is written to call and execute each code, manage the feedback of the corresponding results and loop over time. Thus, the coupled modeling starts with the MOOSE-based code to simulate the THM behavior in relation to the operation until fault failure. For the time being, the Mohr-Coulomb failure criterion is used. Once failure has occurred, the bash calls SeisSol to simulate the seismic event based on the MOOSE outputs, e.g. stress, and propagates the rupture through the fault system. The outputs of the SeisSol, e.g. stress, will be imported into the MOOSE simulator to continue the simulation after the seismic event. Therefore, the outputs of each code are considered as initial counterpart conditions for the next step in the loop. Looping will continue for the predefined duration of the field operation.

How to cite: Habibi, R., Ulrich, T., Gabriel, A.-A., Wasserman, J., and Gaucher, E.: Coupling of thermo-hydro-mechanical modeling with seismicity modeling in a faulted geothermal reservoir, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16775, https://doi.org/10.5194/egusphere-egu24-16775, 2024.

EGU24-16867 | ECS | Posters on site | ERE5.3

Connectivity Anisotropy of fracture network: A connected branch approach 

Pradeep Gairola, Vaasudev Rawat, and Sandeep Bhatt

Fracture networks play a crucial role in various natural processes, including fluid flow in subsurface reservoirs, seismicity, and the overall mechanical behavior of rocks. Understanding the anisotropic nature of connectivity within these networks is essential for accurately modeling and predicting subsurface processes. By adopting a connected branch approach, the study explores the directional variation of branches within these networks which shed light on the preferential pathways and their impact on overall connectivity. This approach enables a comprehensive analysis of the network's structural complexities, providing valuable insights into the anisotropic behavior of fractures.

Our study employs fractal geometry to quantify the connectivity anisotropy of fracture networks. Fractal dimensions are a powerful tool to characterize the intricate and self-repeating patterns inherent in fracture distributions. By applying these dimensions in different orientations, we reveal the directional variations in connectivity, providing a comprehensive analysis of the network's anisotropic behavior. The results contribute to the fundamental understanding of geological processes and have practical implications for various industries, such as oil and gas exploration, geothermal energy extraction, and underground waste storage. This research presents a step forward in unraveling the complexities of fracture networks, offering valuable insights for improved reservoir characterization, enhanced resource recovery, and more accurate subsurface fluid flow predictions in geoscience and engineering applications.

How to cite: Gairola, P., Rawat, V., and Bhatt, S.: Connectivity Anisotropy of fracture network: A connected branch approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16867, https://doi.org/10.5194/egusphere-egu24-16867, 2024.

Tectonic formation, fault activity, and earthquakes are influenced by the concentration of fluid within the Earth's crust. In this work, we aim to unravel the spatial and temporal evolution of fluid transport properties during fault growth to gain insights into the dynamics of fluid flow and its impact on fault development. This is done by taking advantage of a rich data set of measurements of stress, deformation, fluid flux, local pore pressure and acoustic emission locations, coupled with three-dimensional numerical simulations.

We induced quasi-static failure in an initially intact sample of Westerly granite under triaxial conditions. Fault growth was monitored using acoustic emission locations. Deformation was periodically halted to conduct flow-through tests, during which pore pressure heterogeneity and flow rate were measured. The exact geometry of the tested sample was then numerically reconstructed, and three-dimensional finite element simulations of Darcy flow were employed to estimate the heterogenous fluid flow properties for all the stages of the experiment by least-square minimisation within an adjoint framework. For each stage of the test the following two models of permeability heterogeneity were considered: i) different local permeability values are inverted for a regular grid in the fault zone and for the remaining volume of the sample; ii) empirical coefficients are inverted to link the change in permeability within the sample to the acoustic emission event density.

We were able to identify the stages during the faulting process where the permeability undergoes the most significant changes: in the initial stages following peak stress, the permeability of the fault zone increases, reaching up to approximately 150 times the permeability of the bulk. The subsequent significant increase (up to approximately 400 times the permeability of the bulk) occurs when the equivalent fault slip ranges between 0.6 and 0.7 millimetres. No substantial increase is observed for the remaining stages of the faulting process. We were also able to determine the extent of permeability heterogeneity along the shear fault zone, revealing variations of up to 8 times between different zones within the fault volumes. These variations are dependent on the specific stage of the faulting process.

How to cite: Farsi, A., Aben, F., and Brantut, N.: Fluid Transport Properties Heterogeneity Evolution During Fault Growth: Coupling Realistic Fluid Flow Simulations with Triaxial Experimental Data and Pore Pressure Heterogeneity Measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20932, https://doi.org/10.5194/egusphere-egu24-20932, 2024.

EGU24-2591 | Orals | ERE5.4

SRIMA: A fast tool to assess seismicity and seal integrity related to fluid injection. 

Peter Fokker, Loes Buijze, Maarten Pluymaekers, Chris Maaijwee, Harmen Mijnlieff, Job Mos, Bouko Vogelaar, Sjoukje de Vries, and Mark Vrijlandt

The safe and effective deployment of geothermal energy and storage of carbon dioxide requires an assessment of potential induced seismicity and fracturing through the seal above the reservoir. To aid such assessment we have built the SRIMA tool (Seal and Reservoir Integrity through Mechanical Analysis) and we have made it available online. The tool can be used in the Standard extended Seismic Hazard Analysis, which is part of the seismic hazard and risk assessment for geothermal projects in the Netherlands. SRIMA is a fast semi-analytical tool that provides a scenario-based analysis of pressure and temperature changes around an injection well, the resulting stress changes on nearby faults, reactivated fault area, the maximum credible earthquake magnitude, the resulting PGV distribution and an estimate of damage. SRIMA also computes the potential for development of tensile fracture in the seal and base. SRIMA has been designed to give first-order estimates of these results. The speed of the calculations facilitate them to be performed in a stochastic framework, which allows the assessment of failure probabilities.

 

SRIMA is based on semi-analytical expressions for the fast calculation of temperatures, pressures, and induced poro-elastic and thermo-elastic stresses due to the injection of cold fluid. The expressions for flow and induced stresses have been developed for a homogeneous, isotropic layer cake model under radial symmetry. In the injection layer the flow is assumed to be fully developed and temperature transfer is in an advective way. In the bounding seal and base layers, the pressure and temperature dynamics are assumed diffusive. The derived expressions capture the first-order characteristics of the pressure, temperature and stress changes. Validation of the expressions has been achieved through comparison with finite-difference and finite-element codes for temperature, pressure, and stress changes around an injection well. A fault without offset cutting through the seal, reservoir, and base can be specified within the model space. Poro-elastic and thermo-elastic stress changes are transformed to fault stresses and fault criticality. The fault area over which stresses are critical (i.e. fault reactivation occurs) is used to estimate the magnitude of the largest credible earthquake for each model scenario, assuming that the entire reactivated fault area participates in a single event, slip cannot propagate beyond the reactivated area, and all assumed slip over the fault area is seismic slip. An ensemble of magnitudes is converted to exceedance curves of peak ground velocities (PGV), using nationwide developed Ground Motion Prediction Equations. The resulting PGV distribution as a function of epicentral distance serves as input for calculating the probability of exceeding Damage State 1 using empirical fragility functions for unreinforced masonry buildings. This contribution will summarize details and assumptions behind each step.

How to cite: Fokker, P., Buijze, L., Pluymaekers, M., Maaijwee, C., Mijnlieff, H., Mos, J., Vogelaar, B., de Vries, S., and Vrijlandt, M.: SRIMA: A fast tool to assess seismicity and seal integrity related to fluid injection., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2591, https://doi.org/10.5194/egusphere-egu24-2591, 2024.

EGU24-2963 | ECS | Posters on site | ERE5.4

Intense fluid overpressure in the eastern slope of the Yinggehai Basin, South China Sea 

Baibing Yang, Qingfeng Meng, and Fang Hao

The gas-bearing Yinggehai Basin in the northern South China Sea is characterized by high pressure and temperature conditions. The Miocene strata in the eastern slope exhibit intense overpressure with a pressure coefficient exceeding 2.2. Understanding the characteristics of overpressure and clarifying its causes are very important for natural gas exploration and development in reservoirs with intense overpressure. This study identifies and characterizes the pressure structure in the eastern slope of Yinggehai Basin by utilizing formation pressure data from formation tests (MDT) and drill pipe tests (DST) in combination with conventional logging data (acoustic wave, density, and resistivity). The pressure distribution exhibits a distinct three-stage ladder structure. Overpressure initiates in the Lower Pliocene Yinggehai Formation, with a pressure coefficient of 1.2. The formation pressure increases sharply in the underlying Upper Miocene strata (1st member of the Huangliu Formation), with a pressure coefficient ranging from 1.4 to 1.8. The pressure coefficient increases to between 2.1 and 2.3 in the 2nd member of the Huangliu Formation.

We utilized the logging curve combination method, Bowers effective stress method, and Bowers acoustic-density crossplot method to differentiate between two types of overpressure origins: loading and unloading type, and further evaluated their contribution rate to overpressure. Loading overpressure primarily accounts for the overpressure observed in the Yinggehai Formation, contributing to pore pressure with a range from 51% to 93%. In contrast, the overpressure in the Huangliu Formation is predominantly of the unloading type, contributing to pore pressure from 35% to 46%. Additionally, we analyzed the genetic mechanism of overpressure, utilizing lithology, subsidence rate, organic matter maturity, and seismic attribute data. We find that the loading overpressure in the Yinggehai Formation is attributed to unbalanced compaction of mudstone due to rapid sedimentation (sedimentation rate > 500m/ Ma). The unloading intense overpressure in the Miocene strata is most likely caused by the vertical transmission of overpressured fluid along faults and fractures. Our findings provide implications for complex pressure structure, overpressure evaluation, and genetic mechanisms in sedimentary basins.

How to cite: Yang, B., Meng, Q., and Hao, F.: Intense fluid overpressure in the eastern slope of the Yinggehai Basin, South China Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2963, https://doi.org/10.5194/egusphere-egu24-2963, 2024.

In the aggregate quarries in Çiftalan and Ağaçlı (Eyüpsultan, Turkey) regions, grovak-shale type rocks belonging to the Thracian Formation are used as concrete and asphalt aggregates. After crushing, these rocks are classified into 0-5 mm, 5-12 mm and 12-24 mm sizes and marketed as concrete and asphalt aggregates. Aggregates with sizes larger than 5 mm can be used directly in concrete and asphalt applications without any washing process, while aggregates with sizes smaller than 5 mm are called fine aggregates and are marketed after the washing process since the methylene blue value is too high for concrete and aggregate. After the washing process, grains smaller than approximately 100 microns in size (especially clay minerals) are stockpiled in waste sites. Within the scope of this study, it is aimed to produce sinter aggregates with strength that can be used in concrete from these waste materials. It was determined that the waste materials with a grain diameter of less than 100 micron consisted of 28.6% quartz, 21.9% albite, 17% muscovite, 24.9% chlorite and 3.6% calcite minerals. In addition to minerals, 3.4% organic matter was detected. In addition, the main oxide compositions of these wastes were determined, and it was found that 54.51% SiO2, 18.1% Al2O3, 19.66% sum of fluxes (CaO, Na2O, Fe2O3, K2O, MgO) and 5.8% loss on ignition. Within the scope of determining the thermal properties of the wastes, DTA analyzes were carried out and it was determined that two different endothermic reactions took place in the range of 500-600 °C and 700-800 °C, thus dehydroxylation reactions took place in these temperature ranges. In the range of 1000-1100 °C, it was determined that an exothermic reaction, that is, a new phase or several phases were realized. Considering these thermal properties of the wastes, 1100 °C was determined as the sintering temperature. For the sintering process, the samples were first dried at 105 °C and then milled and powdered again. The powdered samples were placed in a metal cell with a diameter of 5 cm and a height of 10 cm and then compressed with a load of 200 kg per cm2. The compressed samples were heated to 1100 °C in a high temperature furnace with a temperature increase of 10 °C per minute and kept at 1100 °C for 30 minutes and then allowed to cool in the furnace. Since the height of these sintered cylindrical specimens was less than 10 cm, the Brazilian test method was used to determine their strength. As a result of the experiment, it was determined that the Brazilian test strengths of 3 different specimens reached 8.8 MPa, 9.6 MPa and 15.7 MPa. Considering the strength values obtained, it was determined that ideal products for concrete and asphalt aggregate can be produced from the dust wastes released in these aggregate quarries. 

How to cite: Avci, E. and Tugrul, A.: Utilization of clay-containing aggregate sludge waste as structural concrete and asphalt aggregate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4757, https://doi.org/10.5194/egusphere-egu24-4757, 2024.

EGU24-5213 | Posters on site | ERE5.4

A  constraint-enhanced machine learning model for predicting hydraulic conductivity of unsaturated bentonite 

Reza Taherdangkoo, Thomas Nagel, and Christoph Butscher

The accurate determination of hydraulic conductivity in unsaturated bentonite is important for the modeling of subsurface thermo-hydro-mechanical and chemical processes. This study introduces a new hybrid approach, employing a constrained CatBoost algorithm coupled with a genetic algorithm for hyperparameter tuning. We benchmarked the effectiveness of the constrained CatBoost model against various data-driven regression models, including lasso, elastic net, polynomial regression, k-nearest neighbors, decision tree, bagging tree, random forest, and standard CatBoost. Our findings demonstrate that the constrained CatBoost model excels in providing accurate estimations of the hydraulic conductivity of compacted bentonite during the wetting phase. The model adequately captures the U-shaped correlation between hydraulic conductivity and suction and reflects the influence of temperature changes on hydraulic conductivity. Furthermore, the bootstrapping analysis, conducted across 800 iterations, confirms the stability and robustness of the constrained CatBoost model. This work provides a reliable tool for predicting hydraulic conductivity in diverse environmental and engineering contexts.

How to cite: Taherdangkoo, R., Nagel, T., and Butscher, C.: A  constraint-enhanced machine learning model for predicting hydraulic conductivity of unsaturated bentonite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5213, https://doi.org/10.5194/egusphere-egu24-5213, 2024.

EGU24-6340 | Posters on site | ERE5.4

Stress transfer and poroelastic mechanisms to elucidate seismicity triggered by reservoirs 

Sandro Andrés, David Santillán, Miguel Ángel Santoyo, and Luis Cueto-Felgueroso

Induced seismicity has attracted increasing research interest in recent times. This phenomenon is generally associated with fluid injection or extraction wells, in energy industry activities such as hydrocarbon extraction/injection, CO2 sequestration, geothermal energy or underground storage of green hydrogen. However, there are other human activities that can induce or trigger seismic events, such as oscillations in the surface water level due to the construction of hydraulic infrastructures.

Surface water level oscillations, whether natural or anthropogenic, can alter the pore pressure regime in the subsurface. Although these alterations usually have a moderate magnitude, they can destabilize faults that were already close to overcoming their slip resistance and eventually trigger an earthquake. On the other hand, the fault slip itself alters the pressure regime due to the undrained response of the porous medium, caused by the sudden deformation of the fault surrounding area. This undrained pressure, which can take up to weeks to dissipate, can alter the stress state of other nearby fractures and trigger new earthquakes or aftershocks.

In this work we present numerical simulations of the underground area around the Itoiz dam (Spain). We simulate the subsurface as a saturated poroelastic medium, with a fully coupled scheme between fluid flow and solid deformation in the porous medium. Through a seismological analysis we start from series of recent earthquakes to locate geological faults. With our numerical model we study how the undrained effect produced by this series of events can destabilize other nearby faults. We also add the effects of the oscillations in the reservoir level following the historical series of the last years.

Our numerical simulations indicate that in the case of the Itoiz dam, the most recent seismic swarm could have been triggered by the stress transfer from the previous events, which, together with the filling of the reservoir, may have destabilized faults that were critically stressed for failure. Our simulations can contribute to explore how the combined effect of the undrained pressure by the fault slip and the oscillations of the reservoir can trigger faults that, due to the natural state of stress, are already close to slip. Also to clarify if the most relevant mechanism is the oscillation of the reservoir level or the undrained pressure trigger, which according to bibliographic analysis can be of the same magnitude. This could apply to other cases of seismicity induced by hydraulic infrastructures or in general by oscillations in the surface water level.

Acknowledgements

This research Project has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid under grant APOYO-JOVENES-21-6YB2DD-127-N6ZTY3, RSIEIH project, research program V PRICIT.

How to cite: Andrés, S., Santillán, D., Santoyo, M. Á., and Cueto-Felgueroso, L.: Stress transfer and poroelastic mechanisms to elucidate seismicity triggered by reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6340, https://doi.org/10.5194/egusphere-egu24-6340, 2024.

Cobalt is often released into the natural environment through industrial waste from alloying industries and acid mine drainage. Additionally, it exists as a radionuclide (60Co) contributing to high-level radioactive waste. Smectite is a mineral that can be useful for adsorption and isolation of this element. In this investigation, Cheto-type montmorillonite (Cheto-MM), a source clay mineral of The Clay Mineral Society's (CMS) with well-established characteristics, was used as the primary material. The study aimed to assess how cobalt adsorption is affected by the adsorption site in the presence of interlayer water and after subsequent dehydration through heating. Adsorption kinetics and adsorption isotherm models were employed to explore the cobalt adsorption mechanism on Cheto-MM.

Results demonstrated notable variations in adsorption characteristics post-dehydration and subsequent shrinkage. Approximately 38% of cobalt was found to adsorb at the edge of Cheto-MM, while about 62% was adsorbed at the interlayer site, indicating the significant influence of the interlayer on cobalt adsorption in Cheto-MM. Adsorption kinetic models showed that the cobalt adsorption kinetics on Cheto-MM can be explained by a pseudo-second-order model. Moreover, isotherm experimental result was best represented by the Langmuir isotherm adsorption model. This study provides fundamental insights into cobalt adsorption characteristics on montmorillonite, emphasizing distinct adsorption sites. Such findings are instrumental in predicting smectite's adsorption behavior in high-level radioactive waste disposal sites in the future.

How to cite: Kim, Y. and Jang, Y.: Cobalt adsorption on montmorillonite: investigating the influence of dehydration on adsorption properties, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8326, https://doi.org/10.5194/egusphere-egu24-8326, 2024.

Large scale subsurface gas storage in porous reservoirs can play an important role in the energy transition. Geological storage of carbon dioxide will mitigate CO2 emissions while underground energy storage, for example in the form of hydrogen gas, can be used to balance out the renewable energy production and demand. To investigate the feasibility of large scale subsurface gas storage in porous reservoirs, simulation models are needed that accurately capture the multi-phase flow behaviour in porous rock. Important input parameters for reservoir simulators are relative permeability and capillary pressure which highly depend on the wettability of the system. In this presentation, we will show results of different experimental techniques to characterize and visualize gas transport in porous rock including a novel experimental device to characterize wettability under the impact of different driving forces.

How to cite: Boon, M.: Experimental characterization of multi-phase flow in porous rock relevant for subsurface gas storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8330, https://doi.org/10.5194/egusphere-egu24-8330, 2024.

Scaling refers to the accumulation of solid precipitates on the surfaces of pipes, heat exchangers, and other equipment across various industrial processes, notably within geothermal systems. This process can lead to decreased efficiency and increased maintenance needs, highlighting the importance of accurate prediction and control methods.

Hydrogeochemical models tend to overestimate the extent of scalings, especially if the scalings are caused by a disruption of the lime-carbonic acid equilibrium due to degassing in the geothermal fluid. This is because the models are not capable to describe diffusion-limited crystal growth, partial volume effects, and local saturation states adequately. In this study we introduce a novel approach by coupling a multiphase CFD-model (OpenFOAM) for the description of the gas phases in the produced geothermal fluids with PhreeqC to simulate the hydrochemical effects of the stripping of CO2 by the gas phase. This results in a model with high spatial and temporal resolution which allows to quantitatively differentiate between processes in the fluid and the processes taking place at the solid interfaces (pipe walls or matrix).

The code is validated with published experiments in bubble columns. The coupling results in a highly flexible model which can account for different hydrochemical conditions, different matrix, and varying gas composition using a well established thermodynamic database. Transfer to other hydrochemical conditions is therefore facilitated.

How to cite: Omidi, M. and Baumann, T.: Coupling OpenFOAM and PhreeqC to quantify local disruptions of hydrochemical equilibria due to bubble formation and stripping of CO2, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8331, https://doi.org/10.5194/egusphere-egu24-8331, 2024.

EGU24-10763 | ECS | Posters on site | ERE5.4

Pore pressure evolution in media with isotropic and anisotropic permeability - analytical and numerical solutions 

Tatia Sharia, Andreas Rietbrock, Birgit Müller, and Thomas Niederhuber

Understanding perturbations caused by underground fluid injection and extraction is essential for steady long-lasting operations of subsurface energy systems (e.g. geothermal systems). The systems are often too complex to obtain precise analytical solutions and computationally expensive to have fine numerical results. Simplified settings give the benefit of understanding the role of driving geological parameters as well as examining the limits of each approach. In this study, we focus on the influence of permeability on pore pressure and present analytical and numerical solutions of spatial and temporal evolutions of pore pressure in an elastic homogeneous porous media with isotropic and anisotropic permeabilities. We use COMSOL Multiphysics to build a 3D finite element model with injection/production wells and investigate where the numerical solutions of the spatially limited volume coincide and diverge from corresponding analytical solutions of pore pressure in infinite media.

How to cite: Sharia, T., Rietbrock, A., Müller, B., and Niederhuber, T.: Pore pressure evolution in media with isotropic and anisotropic permeability - analytical and numerical solutions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10763, https://doi.org/10.5194/egusphere-egu24-10763, 2024.

EGU24-11143 | ECS | Orals | ERE5.4

Estimation of seismic velocity changes in a HT-ATES system using THM modelling 

Clara Fraile, Thomas Kohl, and Emmanuel Gaucher

In Central Europe, a substantial emitter of CO2 in the energy sector corresponds to the thermal energy required for heating and cooling. Seasonal underground heat storage presents a viable option for storing excess heat generated during the summer months for usage in winter, reducing the need for conventional sources of energy. Today, high-temperature aquifer thermal energy storage (HT-ATES) systems are attracting large interest as they represent a sustainable means of meeting heat demand.

In HT-ATES systems, hot water is injected into a reservoir during summer, while exchanged cold water is injected over the winter season. These fluctuations in temperature and pressure have an impact on the geomechanical and thermo-hydraulic properties of both the reservoir and the surrounding layers. Monitoring the changes in the reservoir properties is a critical aspect of running a heat storage system safely and efficiently. We try to determine whether active seismic imaging could be a suitable method to characterize the temporal and spatial evolution of the reservoir.

With view on designing future geophysical assessment and monitoring systems, we first perform thermo-hydro-mechanical (THM) modelling to estimate the variations in the poroelastic properties due to the geothermal processes. Our modeling is based on the characteristics of the DeepStor demonstrator, currently under development in the north of Karlsruhe (Germany), at the Karlsruhe Institute of Technology (KIT). The three layers model includes different mechanical properties with one borehole. The simulation of cyclic hot water injection and production over time allows to quantify its effect on the underground material properties. In addition to assessing the expected operational parameters of the DeepStor demonstrator, we test additional injection schemes with varying underground properties to simulate the different ranges of porosity changes and look at their effects on the elastic properties.

Linking the THM model parameters to seismic sensitive variables such as velocities and impedances, through empirical equations, allow us to determine the conditions under which active seismic surveys could effectively detect these changes. This approach provides a valuable tool for evaluating the potential of active seismic imaging for monitoring HT-ATES systems.

How to cite: Fraile, C., Kohl, T., and Gaucher, E.: Estimation of seismic velocity changes in a HT-ATES system using THM modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11143, https://doi.org/10.5194/egusphere-egu24-11143, 2024.

EGU24-12464 | ECS | Posters on site | ERE5.4

From pore to well - identifying clay mineral distribution in sandstones using SWIR spectroscopy 

Dmitry Bublik, Sebastian Mulder, and Johannes Miocic

Fluid extraction from geological formations for purposes of subsurface utilization leads to a pore pressure drop in reservoirs and potentially to compaction and seismicity. The geomechanical behaviour, and thus production-related compaction, of siliciclastic reservoirs is governed by the composition of reservoir sandstones, which includes porosity, grain size distribution, and detrital and authigenic mineralogy.

One siliciclastic reservoir which is undergoing compaction related to fluid extraction is the Rotliegend of the Groningen gas field. In this research, we investigate potential approaches to upscale the sandstone composition from the micro-scale (thin sections, plugs) to the well and reservoir scale eventually.

Previous research has highlighted that among the petrographic properties, the presence of authigenic clays tends to affect the geomechanical behaviour the most. Intragranular clays can affect the overall stiffness of the individual grains while the presence of the pore-filling clays  and clay rims may result in grain slip or pressure solution in loaded rock samples. In particular, we are defining the fractions of the clay-coating minerals (illite, kaolinite, etc.) and their effect on the inelastic deformation of reservoir sandstone as well as paying close attention to the presence of chlorite as its distribution corresponds to the areas associated with increased subsidence and seismicity.

We employed Short-Wave Infrared (SWIR) spectroscopy, a non-destructive and time-efficient technique, to obtain the mineralogical composition of core slabs from the Groningen Gas field. The SWIR data, based on a resolution of 200 µm pixels, allows for a detailed analysis of compositional variation within the Upper Rotliegend Group. Verification of the SWIR results against a comprehensive petrographic dataset, including X-ray diffraction, thin section descriptions, and modal point count analysis highlights that SWIR data primarily captures qualitative variations in mineralogy rather than providing precise numerical values. Combination of sedimentary facies, SWIR spectroscopy data and conventional petrographic studies allows to generate descriptive mineralogical trends for each of the studied wells.

Ultimately, the results of our research will serve as a foundation for selecting the samples, designing geomechanical experiments to test the proposed hypotheses, and as the means to select the upscaling and modelling approaches to develop a detailed model of the Dutch subsurface that matches well the existing heterogeneous structures. The derived 3D reservoir composition model of the Groningen gas field will be combined with the results of the deformation experiments to link reservoir composition to geomechanical behaviour. This will enable an updated, more realistic, 3D geomechanical model of the Groningen gas field that can be utilised by other researchers to better predict future compaction and subsidence.

How to cite: Bublik, D., Mulder, S., and Miocic, J.: From pore to well - identifying clay mineral distribution in sandstones using SWIR spectroscopy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12464, https://doi.org/10.5194/egusphere-egu24-12464, 2024.

EGU24-14166 | Posters on site | ERE5.4

Anion Transport Through Bentonite Under Various Geochemical Conditions 

Magdalena Krol, Farhana Chowdhury, Sifat Papry, Md Abdullah Asad, Pulin Mondal, Tarek Rashwan, and Ian Molnar

The use of bentonite clay in industrial applications is widespread: it is used as an engineered barrier for long-term management of radioactive wastes, CO2 storage, landfill liners, and contaminant containment. These applications have diverse environmental conditions ranging from various temperatures, pHs, saline contents, and ionic concentrations. Since bentonite is a low permeability clay, anion transport is diffusion dominated but geochemical reactions can also play a significant role and transport will be affected by environmental conditions. In this study, anion transport (bisulfide) under various conditions was examined using experimental and numerical techniques to understand the various geochemical and surface mediated reactions that are occurring in the bentonite. The case study presented is for the use of bentonite in long term storage of nuclear waste but can be extended to other applications.

First, diffusion experiments were performed to examine the transport and reactive nature of bisulfide (HS-) through bentonite compacted at dry density of 1090-1330 kg m-3. Experimental data of bisulfide transport were fitted using the inverse solution technique of Hydrus-1D model and different fitting parameters (e.g., diffusion, sorption, and reaction sink). Simulation results suggest that the HS- sorption/reaction affecting itsdiffusive transport through bentonite can be modeled using a simple nonlinear adsorption process.

Second, batch experiments were performed to understand the maximum allowable sorption that could take place under key geochemical conditions, including temperature, pH, and ionic strength. The results of batch sorption experiments performed suggest that HS- sorption increases with increasing temperature but decreases with increasing pH and ionic strength.

Lastly, since transport and reactive processes are interconnected, the results of these experiments were incorporated into a 1D transport COMSOL model to understand which geochemical process governs bisulfide transport through bentonite. Various processes were examined including linear and non-linear sorption, reactive transport, and anion exclusion. The model was validated using the experiments and showed that HS- was retained in the bentonite due to reactive processes and anion exclusion effects.

How to cite: Krol, M., Chowdhury, F., Papry, S., Asad, M. A., Mondal, P., Rashwan, T., and Molnar, I.: Anion Transport Through Bentonite Under Various Geochemical Conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14166, https://doi.org/10.5194/egusphere-egu24-14166, 2024.

EGU24-15531 | ECS | Orals | ERE5.4

Effects of pore fluid chemistry  on the localized to ductile transition of sandstone. 

Francesco Lazari, Gabriel Meyer, and Marie Violay

In geothermal reservoirs, pore fluid chemistry can affect mechanical and hydraulic properties of rocks inducing mineral dissolution, precipitation, weakening and alteration. Moreover, with increasing pressure and temperature deformation mode can change from localized to ductile (diffused), leading to a major decrease in permeability, thus affecting the exploitability of the reservoir. The effect of fluid chemistry on the transition between localized and ductile deformation of rocks is still marginally understood.

To investigate the effect of water presence and fluid chemistry on localized and ductile deformation, two sets of triaxial experiments (at 20 and 100 MPa effective confinement pressure, in the localized and ductile field respectively) were performed on a porous silicate sandstone (Adamswiller sandstone), dry, with deionized water and with a 6 M NaCl solution (Na+ rich solution), with a 0.1 M HCl solution (pH 1 solution) and a 0.1 M NaOH solution (pH 13 solution). To complement the mechanical properties, complex spectral electrical conductivity was measured during deformation to monitor pore fluid ion content; pore fluid was collected at the beginning and at the end of the experiments and analyzed with ICP-MS; post-mortem microstructural analyses were performed.

In the localized domain, both water presence and pore fluid chemistry had a marginal effect on the strength of the rock, leading to a 5/10% strength reduction over dry rock strength indipendently of the pore fluid composition. In the ductile domain, de-ionized water weakens the rock by 25%, a Na+-rich or pH 1 fluid leads to a 35% weakening and a pH 13 fluid weakens the rock by 40% over dry rock strength. Spectral electrical conductivity does not change during localized deformation, while it increases by 2 to 5 times during ductile deformation when the rock is saturated with deionized water; conductivity does not change with the Na+-rich fluid regardless of the deformation mode and conductivity decreases by half an order of magnitude with both pH 1 and pH 13 fluids both with localized and ductile deformation.

 
 

How to cite: Lazari, F., Meyer, G., and Violay, M.: Effects of pore fluid chemistry  on the localized to ductile transition of sandstone., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15531, https://doi.org/10.5194/egusphere-egu24-15531, 2024.

EGU24-16640 | ECS | Orals | ERE5.4

Decentralized CO2 storage in unfavorable conditions: An example from Switzerland 

Thanushika Gunatilake, Antonio Pio Rinaldi, Alba Zappone, Yingqi Zhang, Dominik Zbinden, Marco Mazzotti, and Stefan Wiemer

The escalating global temperature necessitates immediate action to mitigate greenhouse gas emissions. Geological Carbon Storage (GCS) technology has emerged as a promising solution, specifically by injecting carbon dioxide (CO2) into geological formations, particularly deep saline aquifers. However, finding ideal geological reservoir conditions, including caprock stability and storage capacity, is a rare occurrence.

This study comprehensively assesses the potential for CO2 storage in the Triemli saline aquifer in Zurich, Switzerland. The goal is not only to demonstrate the feasibility of CO2 storage in Switzerland but also to emphasize the viability of decentralized storage with multiple small injection point, for emitters like medium -sized citiesin regions with geologically challenging subsurface conditions. Through numerical simulations, we explore CO$_2$ injection, migration, and long-term reservoir stability to bridge the gap between theoretical estimates and practical feasibility.  Our findings underscore the potential of deep saline aquifers for CO2 storage in Switzerland, particularly in the Swiss Molasse Basin and the adjacent Folded Jura, identified as crucial regions for effective CO2 storage. Employing advanced methods and strategic injection techniques, such as multiple vertical or horizontal injection points along a single well, could optimize this storage capacity to approximately 3 million tons of CO2 over the same period.

How to cite: Gunatilake, T., Pio Rinaldi, A., Zappone, A., Zhang, Y., Zbinden, D., Mazzotti, M., and Wiemer, S.: Decentralized CO2 storage in unfavorable conditions: An example from Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16640, https://doi.org/10.5194/egusphere-egu24-16640, 2024.

Deep underground geological disposal is widely accepted as one of the most appropriate ways for the long-term safety and management of radioactive waste. The heat generated by the nuclear waste decay brings elevated temperature increase, which may affect the thermo-hydro-mechanical (THM) behaviour of the host rock. A correct evaluation of the thermal impacts on the host rock behaviour is important for the design of the underground geological disposal.

With the temperature increases, thermal pressurization is observed both in the small (laboratory) and large (in-situ) scale tests. Physically, the overpressure induced by the discrepancy of the thermal expansion coefficient between the solid and fluid phases may potentially induce fracture re-opening and propagation. The host rock located in the middle of two adjacent cells may suffer shear or tensile failure, which is dependent on the intensity of the thermal power and the distance between the neighbouring cells. Some research work also shows that soil characteristics like cohesion, elastic modulus and water viscosity are influenced by the rise in temperature [1]. To investigate the thermally induced change on the mechanical property of host rock, triaxial compression tests were conducted at the University of Lorraine at different temperatures (20, 40, 60, 80, 100 and 150 °C), confining pressures (0, 4 and 12 MPa) and samples orientations (parallel and perpendicular to the bedding plane). The results showed the transitory overpressure induced by the thermal dilation during the initial heating, and the degradation of the mechanical strength of the host rock with the increase in temperature [2].

Based on the experimental observations, the triaxial compression tests are represented in a two-dimensional axisymmetric coupled THM model. The modelling is composed of the two steps: isotropic loading (increase confining stress and temperature), and shear process (increase axial loading). The numerical FEM code is LAGAMINE from the University of Liège. The Callovo-Oxfordian (COx) claystone, relying on its low permeability and good plasticity, has been selected as the host rock for the underground geological disposal in Meuse/Haute-Marne in France. The objective of this study is to introduce thermal-mechanical modelling involved with thermal plasticity. The cohesion of the host rock is defined as a function of the temperature to describe the thermally induced change of mechanical behaviour of the host rock. This model will then be validated against experimental observations in the laboratory and further applied to the large-scale heating test.

ACKNOWLEDGEMENT

This study was performed in the framework of the European Joint Programme on Radioactive Waste Management (EURAD). EURAD has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 847593.

REFERENCES

[1] Laloui, L. and Cekerevac, C., 2003. Thermo-plasticity of clays: an isotropic yield mechanism. Computers and Geotechnics, 30(8), pp.649-660. Doi : https://doi.org/10.1016/j.compgeo.2003.09.001.

[2] Gbewade, C.A.F., Grgic, D., Giraud, A. and Schoumacker, L., 2023. Experimental study of the effect of temperature on the mechanical properties of the Callovo-Oxfordian claystone. Rock Mechanics and Rock Engineering, pp.1-22. Doi : https://doi.org/10.1007/s00603-023-03630-7.

How to cite: Song, H. and Collin, F.: A thermal-mechanical constitutive modelling for Callovo-Oxfordian Claystone in the context of nuclear waste disposal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16781, https://doi.org/10.5194/egusphere-egu24-16781, 2024.

EGU24-16823 | ECS | Orals | ERE5.4

A multi-scale model to study gas transport processes in clay materials 

Gilles Corman and Frédéric Collin

In the field of radioactive waste confinement, the question of gas transfers in clay formations is a crucial issue. A certain amount of gas, such as Hydrogen may be generated during the exploitation phase in the nearfield by the deterioration of the metal components of the system. As the host medium is characterised by a very low permeability, various gas transport processes could occur as a function of gas accumulation and pressurization [1], including the development of preferential gas pathways through the sound rock mass, which could lead to undesirable changes in the favourable containment properties of the host rock.

There is a growing body of experimental evidences [2, 3] that natural heterogeneities and pre-sxisting fractures in clay-rich materials represent preferred weaknesses for the process of opening discrete gas-filled pathways. Capturing the related transport mechanisms therefore requires to go from macroscopic to microscopic scale. Hence, a multi-scale modelling approach that models the micro-scale effects explicitely on their specific length scale and couples their homogenized effects to the macro-scale is proposed in the present work. Based on a periodicity assumption of the microstructure, a relevant Representative Element Volume (REV) is defined based on experimental data, which makes it possible to idealise the flow behaviour of the material microstructure with different families of discontinuities, and an assembly of tubes substituting the porous matrix blocks. This complete hydraulic constitutive model is solved at the scale of the microstructural constituents, and is directly affected by the mechanical effects tackled at the macroscopic scale, which makes the whole model hydro-mechanically coupled.

This model has been subsequently applied to simulate a gas injection test parallel and perpendicular to the bedding of initially saturated samples of Boom Clay [3]. This analysis provides a rather good agreement with the experimental results in terms of pressure response, outflow volume and average axial strain. In addition, it allows to simulated the creation of a preferential flow pathway along the sample axis (Figure 1b, top), which serves as basis to numerically reproduce the development of random pathways through the sample in plane strain state (Figure 1b, bottom), and aims to improve the mechanistic understanding of the gas transport processes at play in clayey barriers.

[1] P. Marschall, S. Horseman, and T. Gimmi. Characterisation of Gas Transport Properties of the Opalinus Clay, a Potential Host Rock Formation for Radioactive Waste Disposal. Oil & Gas Science and Technology Rev. IFP, 60(1):121-139, 2005. 

[2] Harrington, J.F., Milodowski, A.E., Graham, C.C., Rushton, J.C., & Cuss, R.J. (2012). Evidence for gas-induced pathways in clay using a nanoparticle injection technique. Mineralogical Magazine, 76(8):3327–3336.

[3] Gonzalez-Blanco, L., Romero, E., Jommi, C., Li, X. & Sillen, X. (2016). Gas migration in a Cenozoic clay: Experimental results and numerical modelling. Geomechanics for Energy and the Environment, 6:81–100.

How to cite: Corman, G. and Collin, F.: A multi-scale model to study gas transport processes in clay materials, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16823, https://doi.org/10.5194/egusphere-egu24-16823, 2024.

EGU24-17117 | ECS | Posters on site | ERE5.4

Insight into the micromechanisms of gas breakthrough in water-saturated clay-rich geomaterials – Implications for CO2 sequestration 

Craig Allsop, Matteo Pedrotti, and Alessandro Tarantino

The successful deployment of carbon dioxide (CO2) geological sequestration in porous media is reliant on the sealing efficiency of the overlying, clay-rich caprock to act as a physical barrier. Clay-rich caprock formations are considered favorable materials to act as a seal due to them characteristically consisting of small pores providing high capillary entry pressures, hence preventing the intrusion of a non-wetting fluid.

The juxtaposition and availability of deep seated (buried) caprock-reservoir systems to carbon capture and storage clusters may not be available. Therefore, the assessment of shallow seated, weakly consolidated caprock-reservoir systems (e.g., Sleipner) will be required. Our experimental campaign tests analogous caprock geomaterials which have relatively high compressibility, representative of shallow seated (buried or less indurated) clay-rich caprocks.

Past experimental campaigns demonstrate that CO2 breakthrough is dominated by the creation of very localized channels across the sealing barrier which occur at pressures far lower than the one predicted by the Laplace’s equation [1]. However, limited data characterizing these pathways exists. Furthermore, the physical indicators of susceptibility which underly the micro-mechanisms of failure (e.g., fracturing), are still only postulated for clay-rich geomaterials.

where Pc* is the capillary breakthrough pressure [kPa], ψ, reflects pore shape [-], Ts, interfacial tension between water and gas (e.g., CO2), and θ, represents wettability [°].

An innovative experimental set-up which allowed for the onset of surface crack formation to be captured during gas injection (representing the non-wetting fluid in CO2 geological sequestration) into intact clay-rich geomaterials is presented. This allowed for the investigation of physical indicators of susceptibility to gas breakthrough via localized pathways.

Results on different fracture patterns when non-wetting gas (i.e., air) is injected into consolidated clay show the formation of large fractures that nucleate from within the sample. Upon air pressurization, before fracture formation, the sample undergoes volumetric deformation (i.e., consolidation), as the resulting action of the vertical stress applied at the air-water interface (menisci). Once a fracture forms deformation stops and breakthrough occurred at lower pressures than traditionally recorded. The mechanisms of air intrusion are expected to be of a similar nature as CO2 intrusion. Post-mortem assessment of the internal nature of these localized pathways was then visualized using xCT imaging.

As a continuum mechanics framework will not predict fracture formation under our test conditions, it appears that the experimental evidence support the underlying hypothesis that disjoining pressure governs the mechanisms that ultimately control fracture formation and thus, eventually CO2 breakthrough. The disjoining pressure is governed by the electrostatic double-layer interactions, van der Waal’s dispersion forces, structural forces, and solvation forces.

If the pore size distribution is such that high gas pressures are required to overcome capillarity, the gas pressure will force single clay particles apart, displacing water form adjacent interparticle spaces. This represents a localized failure mechanism at the clay interface, resulting in fracture nucleation. It is expected that clay displaying large swelling pressures will subsequently display high gas entry pressure, termed “pathway dilation”. Therefore, pressurized gas will enter a dilated pathway at lower pressures than anticipated.

How to cite: Allsop, C., Pedrotti, M., and Tarantino, A.: Insight into the micromechanisms of gas breakthrough in water-saturated clay-rich geomaterials – Implications for CO2 sequestration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17117, https://doi.org/10.5194/egusphere-egu24-17117, 2024.

The utilisation of geothermal heat as a form of clean energy is experiencing global growth. Many sites designated for geothermal energy extraction are in regions with elevated heat gradients, such as Iceland and Japan. However, the repercussions of the migration of cold fluids in rock formations at high temperatures, and the subsequent fracturing of the host rock, which is relevant in the context of deep geothermal energy systems, remains insufficiently understood.  In this study, we explore the three-dimensional evolution of fractures in 50×9.8×1 mm3  homogeneous slabs of various brittle rocks, subjected to a thermal shock of ΔT=580°C, through numerical simulations over 10 seconds. Initially, we validate our numerical approach using a benchmark of Al2O3  slab, and subsequently, we examine fracture development in granite, basalt, and shales. Our numerical methodology employs a three-dimensional finite-element-based simulator to model thermo-mechanical deformation. The in-house code is a fully coupled THM code which considers damage to predict fracture initiation. Fracture growth is predicted per fracture tip using stress intensity factors. The code uses adaptive meshing and NURBS for fracture surfaces to facilitate mesh-independent fracture growth. In our simulations, we apply triangles and tetrahedra elements to discretise surface and volume elements, respectively. Our results show the development of dozens of fractures in bi- or tri-modality, which penetrate up to 85% of the depth of the slab, for the various simulations. These results demonstrate both qualitative and quantitative agreement between the simulated slab and the benchmark by reproducing the same intertwined short-long fracture patterns and modal distribution of fracture lengths. Furthermore, they illustrate how the fracturing rates (ranging between 1-100 mm/sec), fracture length distribution (unimodal, bimodal or trimodal), and penetration depth of fractures in front of the shock front vary among the different brittle rock types.

How to cite: Suchoy, L., Paluszny, A., and Zimmerman, R. W.: Fracture growth using fully coupled thermo-mechanical model in brittle rocks during thermal shock and resulting network patterns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17626, https://doi.org/10.5194/egusphere-egu24-17626, 2024.

EGU24-18636 | ECS | Posters on site | ERE5.4

Physics-based numerical evaluation of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) in the Upper Jurassic reservoir of the German Molasse Basin 

Kalliopi Tzoufka, Guido Blöcher, Mauro Cacace, Daniela Pfrang, and Kai Zosseder

Concepts of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) (> 50 °C) are investigated for system application in the Upper Jurassic reservoir (Malm aquifer) of the German Molasse Basin (North Alpine Foreland Basin). The karstified and fractured carbonate rocks exhibit favorable conditions for conventional geothermal exploitation of the hydrothermal resource. Here, to further assess the sustainability of HT-ATES development in the Upper Jurassic reservoir, a physics-based numerical analysis is performed. With an estimated heating capacity of ca. 21 MW over half a year, our approach aims at determining numerically the efficiency of heat storage under the in-situ Upper Jurassic reservoir conditions and locally feasible operation parameters.

The numerical models build upon datasets from three operating geothermal sites at depths of ca. 2000-3000 m TVD located in a subset of the reservoir which is dominated by karst-controlled fluid fluxes. Commonly considered as a single homogeneous unit, the 500 m thick reservoir is subdivided into three discrete layers based on field tests and borehole logs from the three considered sites. This introduced vertical heterogeneity with associated layer-specific enhanced permeabilities allows to examine potentially arising favorable heat transfer, and in combination with the facilitated high operation flow rates to evaluate thermal recoveries in the multilayered reservoir.

Computation results reveal that the reservoir layering induces preferential fluid and heat migration primarily into the high-permeability zone, while thermal front propagation into the lower permeable rock matrix is restricted. The simulations further display the gradual temperature increase in the warm wellbore and its surrounding host rock, and the consequent progressive improvement in the heat recovery efficiencies. Despite the elevated permeability that may trigger advective heat losses, heat recovery factor values range from ca. 0.7 over the first year of operation to over 0.85 after 10 years of operation. An additional scenario is examined with fluid injection solely in the high permeable zone, in order to quantify potential improvement in the recovery efficiency by omitting fluid injection in the lower-permeability layers where heat propagation is diminished. This is due to the geometrical shape of the thermally perturbed rock volume as heat losses occur at the interface between thermal front and adjacent reservoir rock. Consequently, conclusions on the performance of the two different system designs under this layered reservoir setting are derived. All simulations account for density and viscosity variation through the IAPWS (International Association for the Properties of Water and Steam) thermodynamic property formulations. Results show that density-induced buoyant fluxes which would considerably decrease thermal efficiencies are inhibited, and thus the prevailing heat transport mechanism is forced convection.

How to cite: Tzoufka, K., Blöcher, G., Cacace, M., Pfrang, D., and Zosseder, K.: Physics-based numerical evaluation of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) in the Upper Jurassic reservoir of the German Molasse Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18636, https://doi.org/10.5194/egusphere-egu24-18636, 2024.

EGU24-19122 | ECS | Posters on site | ERE5.4

Operational Monitoring of Thermal Dynamics in Deep Geothermal Production and Injection Wells with Fiber Optics from the Surface to the Reservoir 

Aurelio Andy, Felix Schölderle, Daniela Pfrang, and Kai Zosseder

In order to gain insights into the hydraulic and thermal long-term behavior of deep geothermal boreholes during operation, a fiber-optic monitoring (FOM) system was implemented at the Stadtwerke Munich's (SWM) geothermal plant 'Schäftlarnstrasse' in the national project Geothermal-Alliance Bavaria (GAB). The permanently installed fiber optic cables enable continuous measuring of the temperature in boreholes with high spatial and temporal resolution via Distributed Temperature Sensing (DTS) and of acoustics/vibration via Distributed Acoustic Sensing (DAS). In 2019, one production and one injection well were equipped with FOM in different setups and have been collecting data since then. In the injector, the cable was cemented behind the anchor pipe in the upper section of the borehole, whereas the producer was equipped with a fiber-optic cable until the total depth of the reservoir. Additionally, a fiber-optic gauge provides pressure and temperature at the top of the reservoir in this well.

Among other things, precise inflow profiling in the reservoir section of the producer could be carried out using the temperature data, which helps deepen the understanding of the hydraulic behavior of the reservoir. Changes over time in the temperature of the produced thermal water can be traced back to changes in the hydraulically active zones or inflow temperatures in the reservoir. Other factors that influence the wellhead temperature, such as borehole heat losses to the surrounding rock, can be quantified using the DTS data.

At the beginning of 2024, a third fiber-optic cable will be installed in an injection well at the Schäftlarnstrasse geothermal site. A similar setup as in the production well will allow for continuous measuring in the entire borehole until total depth (TD) and pressure and temperature from p/T gauges at the top of the reservoir and at TD. Therefore, both production and injection conditions in the reservoir and wellbore will be continuously monitored at all depths using DTS and DAS for the first time.

We present the first interpretations of the data collected from the newly installed FOM in the injection well as well as insights into the long-term monitoring of the hydraulic and thermal dynamics in the production well to underline the importance of permanent downhole monitoring to ensure efficient and sustainable use of the geothermal reservoir.

How to cite: Andy, A., Schölderle, F., Pfrang, D., and Zosseder, K.: Operational Monitoring of Thermal Dynamics in Deep Geothermal Production and Injection Wells with Fiber Optics from the Surface to the Reservoir, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19122, https://doi.org/10.5194/egusphere-egu24-19122, 2024.

EGU24-19876 | ECS | Orals | ERE5.4

Weathering and creep in rocks modelled at the microscale 

Hadrien Rattez, Alexandre Sac-Morane, and Manolis Veveakis

Many natural processes and energy-related project in the subsurface involve the interactions between the porous rock and the fluids inside the pores. In particular, the fluid can interact with the solid matter by various dissolution-precipitation reactions that can modify the microstructure geometry and thus change the mechanical behavior of the rock and its failure potential or directly induce a creep of the rock. These chemo-mechanical couplings can have important implications for storage applications and induced seismicity. In this contribution, we will show discrete element simulations performed at the microstructural scale of porous matter. First, we will show that the dissolution of the cement in sedimentary rocks strongly influence the lateral earth pressure coefficient. The value of this coefficient tends to an attractor by increasing the degree of dissolution, which can lead to stress redistribution at the reservoir scale and promote faulting or induced seismicity. Secondly, we will show a numerical framework coupling discrete element with a phase field model allowing to capture grains shape changes due to local precipitation or dissolution. This model is applied to study the phenomenon of intergranular pressure-solution and allows to reproduce the creep behavior of the material in compaction. It enables also to study the competition between grain rearrangement and pressure solution in fault gouges to induce a rate dependency of the fault mechanical behavior.

How to cite: Rattez, H., Sac-Morane, A., and Veveakis, M.: Weathering and creep in rocks modelled at the microscale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19876, https://doi.org/10.5194/egusphere-egu24-19876, 2024.

EGU24-20645 | ECS | Posters on site | ERE5.4

Joule-Thomson cooling and phase transitions during CO2 injection in depleted reservoirs 

Lucy Tweed, Jerome Neufeld, and Mike Bickle

Depleted oil and gas reservoirs are attractive sites for CO2 sequestration. However, the injection of CO2 into depleted reservoirs carries the potential for significant Joule-Thomson cooling, when dense, supercritical COis injected into a low-pressure reservoir. The resulting low temperatures around the well-bore risk causing thermal fracturing and/or freezing of pore waters or precipitation of gas hydrates which would reduce injectivity and jeopardise near-well stability. Injection into reservoirs at subcritical pressure also leads to a phase transition from liquid to vapour CO2. This is accompanied by cooling, due to the latent heat of vaporisation, and dramatic changes in fluid properties including density, compressibility and viscosity.

We present models of non-isothermal flow of CO2 in the near well-bore region, which demonstrate the controls on cooling and constrain the different pressure-temperature regimes that can emerge. We show that during radial injection, with fixed injection rate, transient Joule-Thomson cooling can be described by similarity solutions at early times. The positions of the CO2 and thermal fronts are described by self-similar scaling relations. The scaling analysis here identifies the parametric dependence of Joule-Thomson cooling. We present a sensitivity analysis which demonstrates that the primary controls on the degree of cooling are the injection rate and Joule-Thomson coefficient. The analysis presented provides a computationally efficient approach to assessing the degree of Joule-Thomson cooling expected during injection start-up, providing a complement to full numerical simulations.

How to cite: Tweed, L., Neufeld, J., and Bickle, M.: Joule-Thomson cooling and phase transitions during CO2 injection in depleted reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20645, https://doi.org/10.5194/egusphere-egu24-20645, 2024.

EGU24-21553 | Posters on site | ERE5.4

Analysis of Wellbore Integrity using DTS Monitoring and Numerical Modelling in the Practice of ATES 

Guido Blöcher, Liang Pei, Stefan Kranz, Christian Cunow, Lioba Virchow, and Ali Saadat

Surplus heat as stored in an ATES (Aquifer Thermal Energy Storage) system in summer could partly meet the increasing demand of energy in winter. Better assessment on the wellbore integrity permits sustainable operation of such systems. Therefore, an artesian flow test was conducted in a research well located in Berlin, Germany. In this test, artesian flow of 16.8°C from Jurassic sand at depths from 220 m to 230 m was produced at 14°C and at a flow rate of 3.6m3/h from the annular space between the production casing and the anchor casing. The depth-resolved temperature at the production casing as monitored using the distributed temperature sensing (DTS) technique manifested the depths of the artesian aquifer. A hydro-thermal coupled numerical model for the artesian flow was calibrated by matching the simulated flow rate to the wellhead-measured values. The simulated and the DTS-monitored temperatures suggested that the heating-up in the near-wellbore materials by the artesian flow was hindered by the deployment-related inclusion of water behind the anchor casing, and the cooling in these materials in the shut-in test stage was enhanced by such inclusion. 

How to cite: Blöcher, G., Pei, L., Kranz, S., Cunow, C., Virchow, L., and Saadat, A.: Analysis of Wellbore Integrity using DTS Monitoring and Numerical Modelling in the Practice of ATES, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21553, https://doi.org/10.5194/egusphere-egu24-21553, 2024.

EGU24-2751 | ECS | Orals | ERE5.5 | Highlight

Thermo-mechanical properties and fracture behavior of granite at pore scale: implications for geological storage 

Chengkang Mo, Junliang Zhao, and Dongxiao Zhang

Geological storage of energy and carbon dioxide requires a deep knowledge of the complex thermo-hydro-chemo-mechanical processes that affect the stability and performance of reservoir rocks. In this study, we investigate the thermo-mechanical properties and mesoscale fracture behaviors of four key minerals in granites: quartz, plagioclase, amphibole, and biotite. We use a combination of experimental and analytical techniques to reveal the microscale mechanisms of rock failure under high temperature and tensile loading.

We perform nanoindentation tests under dynamic heating–cooling cycles to measure the reduced modulus and hardness of the minerals. We also conduct mode I fracture tests under tensile loading conditions to evaluate the fracture toughness and tortuosity of the granite. We observe the dynamic crack propagation and fracture morphology of minerals using scanning electron microscopy. We analyze the structural and physio-chemical changes at high temperatures using X-ray diffraction, thermogravimetric analysis, and Fourier’s transform infrared spectroscopy.

We find that the thermo-mechanical properties and fracture behaviors of the minerals are governed by three main factors: the alterations in mineral structure, the aperture of open cracks along cleavage planes, and the degree of heterogeneity due to mineral composition complexity. We identify two different damage modes in granite: catastrophic and non-catastrophic failure modes. We explain the underlying mechanisms of each mode and show that catastrophic failure has precursory signs, while non-catastrophic failure does not.

Our results provide new insights into the microscale mechanisms of rock failure under high temperature and tensile loading, which have implications for the macroscopic understanding of rock behavior in geological storage applications. By elucidating the microscale intricacies, this study enhances our understanding of the multifaceted interactions that influence the stability and performance of rocks, and supports the development of improved geological storage strategies, such as carbon sequestration and enhanced energy storage.

How to cite: Mo, C., Zhao, J., and Zhang, D.: Thermo-mechanical properties and fracture behavior of granite at pore scale: implications for geological storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2751, https://doi.org/10.5194/egusphere-egu24-2751, 2024.

EGU24-3433 | ECS | Orals | ERE5.5

Pore scale assessment of disrupted hydrochemical equilibria in geothermal systems 

Lilly Zacherl and Thomas Baumann

Many geothermal plants in the north alpine foreland basin (NAFB) are affected by the precipitation of calcium carbonate and struggle with efficiency losses and sometimes safety problems. The adaption and implementation of predictive maintenance strategies relies on the accuracy of the prediction and make sense if the costs of early maintenance are significantly less compared to the costs of a replacement of failed parts. Therefore, the accurate description of the kinetics of inorganic precipitations have to be extended to include the fluid dynamics and the interaction of the precipitates with different materials used in the geothermal cycle. The experimental concept also applies to fluid-rock interactions which can alter the properties of the reservoir.

The parametrization of transferable hydrogeochemical models performs best with data on a single interface, single crystal level. This data allows to elucidate the underlying process kinetics and improve existing strategies. The combination of Raman spectroscopy and Quartz crystal microbalance (QCM) opened a way to quantify the formation of carbonate precipitates. Here, the QCM can measure the total mass of attached particles while Raman microscopy identifies the crystal polymorph. Running these experiments in microfluidic channels allows to assess the effects of physical stress on the formation and to test inhibition and removal stratgies.

The QCM sensor was placed in a microfluidic channel and tap water (carbonate rich, Ca2+ concentration approx. 2.25 mM, pH approx. 7.50) and sodium hydroxide (0.10 M) were injected through the two inlet channels. As the lime carbonic acid equilibrium shifts due to the pH increase, precipitations are formed. The adhesive forces on different materials (SiO2, aluminium, steel) were studied by changing the flow velocities and chemical cleaning processes were mimicked by injecting an acid (HCl).

The precipitation of CaCO3 on the QCM sensor (sensitivity in the low mg-range) was less than 20% of the theoretical amount. This underlines the importance to include the fluid dynamics into the assessment models. The experimental data under dynamic conditions was modelled with a combination of CFD simulations with PhreeqC: The particle flow velocity and the precipitates formed depend on the depth as well as local equilibrium changes. The preferred location of scaling could be adequately simulated. This quantification of the effects of the shear stress and the material properties on the scaling efficiency is a further step towards predictive maintenance strategies and a solid comprehensive site assessment during the planning stage, which should improve the sustainability and the much-needed attractiveness of this energy sector.

How to cite: Zacherl, L. and Baumann, T.: Pore scale assessment of disrupted hydrochemical equilibria in geothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3433, https://doi.org/10.5194/egusphere-egu24-3433, 2024.

CO2-oil-rock interactions and complex pore structure affect the sweep efficiency (ES) and wettability, thus having a significant impact on CO2 enhanced oil recovery in tight oil reservoirs. In this study, we selected 10 rock plugs from the Yanchang Formation, Ordos Basin in China. First, casting thin sections and mercury intrusion capillary pressure were performed to investigate the microscopic pore structure characteristics of the tight rock samples. The results show that pore structure can be divided into three types (RT-I, RT-II, and RT-III) from good to poor qualities. On this basis, CO2 floodings using the Nuclear Magnetic Resonance technique were performed to investigate the influence of pore structure on the ES in large (PL) and small (PS) pore throat intervals. With the increase of displacement pressure, the oil recovery of RT-I, RT-II and RT-III are about 70.9%, 67.8% and 10.16%, respectively. The ES of PL of all samples are similar, while the ES of PS decrease subsequently for the three types. Pressure, mineral composition and the complex pore structure are attribute to the differences. On one hand, higher displacement pressure leads to lower interfacial tension and viscosity, resulting in higher oil recovery. On the other hand, CO2 is more likely to vaporize the light oil components, resulting in the asphaltene precipitation. Quartz with a smooth surface is not easy to precipitate, while most clay minerals are easier to absorb asphaltene and are likely to alter the wettability of pore surfaces. Thus, in comparison to RT-III, the ES of RT-I with a higher quartz content is higher in PS. In addition, the worse the relationship between pore structure configurations, the greater the capillary pressure, causing the different ES between RT-I and RT-II. The findings in this study shed a light on the understanding of complex mechanisms for CO2 EOR in tight oil reservoirs.

 

How to cite: Cheng, Y., Qu, Y., and Cheng, X.: Effect of pore structure and CO2-oil-rock interactions on sweep efficiency of CO2 EOR in tight sandstone reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3479, https://doi.org/10.5194/egusphere-egu24-3479, 2024.

The characterization of reservoir rocks depends on the absolute permeability as a crucial parameter. To estimate this property numerically, one can employ a combination of digital rocks and Stokes flow simulation through the Lattice Boltzmann Method (LBM). In previous studies, the LBM has typically been implemented as an iterative process, wherein iterations are repeated until the parameter estimates between consecutive iterations reach a certain threshold level. However, we argue that this termination criterion is unsuitable and may compromise the accuracy of simulation results.

In this study, we investigate the convergence of the LBM through various tests, including the Poiseuille flow between parallel plates and different types of digital rocks (such as dune sand, sandstone, and carbonates). We find that the logarithm of the relative error, when compared to the estimate at infinite time (representing a stable state), demonstrates a linear relationship with the number of iterations. This linear relationship suggests an exponential rate of convergence. On the other hand, if we rely on the difference in errors between consecutive iterations as the termination condition, the simulation may not reach a stable state.

Instead, we propose a more accurate termination criterion for the LBM simulation by analyzing the decay trend of the error difference. This criterion provides a practical and appropriate approach for the characterization of reservoir rocks. Additionally, we offer a theoretical explanation for the convergence rate, which is linked to the spectral radius of the iterative matrix in linear algebra.

How to cite: Liao, Q.: Convergence Behavior of Lattice Boltzmann Method for Pore-scale Modeling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4648, https://doi.org/10.5194/egusphere-egu24-4648, 2024.

Horizontal well multi-stage and multi-cluster fracturing technology has played an important role in unconventional reservoir development. However, traditional methods rarely investigated fracturing fluid flow characteristics in reservoirs with abundant natural fractures. Furthermore, affected by the stress interference from dense number of fracturing clusters, some perforations do not form fractures. For deep shale reservoirs, failure to consider these contents may result in unsatisfactory fracturing results for deep shale reservoirs.

An innovative approach is introduced in this paper. This innovation can be based on natural fracture development, fracture propagation law and reservoir composition characteristics. The flow regularity of fracturing fluid inside natural fractures was characterized through CT scanning experiments. Numerical simulation is used to analyze fracture propagation in fracturing horizontal well with multi-stage and multi-cluster. Core full component test experiment was conducted to analyze compressibility. In response to the above results, different fracturing process is adopted, the length of fracturing section is adjusted, the number of fracturing clusters is set. Then the fracturing design scheme of each segment is formulated and the fracturing effect and operation lessons of actual wells are analyzed. 

The results show that obvious pressure interference between developed section and undeveloped section of natural fracture, fracturing fluid first enters the extended natural fracture and then enters other fractures. Therefore, the temporary plugging of the extended natural fracture weakens its preferential tendency to enter the fluid and ensures the uniform migration of fracturing fluid to each fracture. Numerical simulation shows that some perforations do not form effective fractures, due to stress interference caused by excessive number of perforations. Hence, a fracturing scheme with fewer perforation times is adopted to reduce stress interference and improve the efficiency of perforating fracture formation. The results also observe that the reservoir contains plenty of brittle minerals such as calcite, which is easy to cause fractures. However, high silicon content easily form, extremely irregular fracture. Consequently, the fracturing scheme of shortening the length of fracturing section is adopted to strengthen the control of fracture expansion. The fracturing evaluation of the effect shows that the initial production of the well was 6.59 ×104 m3 with a flowback rate of 15.5%. Microseismic monitoring data shows that the reconstruction volume has increased from the original 9.70 ×104 m3 to 1.06 105 m3, the fracturing effect is remarkable.

The conclusion of this research supports for deep shale fracturing design and has a vital practical application significance. Compared with conventional fracturing methods, the fracturing performance is significantly improved results from weakening the advanced fluid tendency of natural fractures, decreasing the stress interference between clusters and strengthening the fracture control.

Key words: deep shale; natural fracture; stress interference; brittle mineral content; temporary plugging technology

How to cite: Di, S., Ma, S., Wei, Y., Cheng, S., Miao, L., and Liu, M.: Effective fracturing strategy considering natural fracture, stress interference and rock component—A practical application of Dingshan block in Sichuan Province of China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5027, https://doi.org/10.5194/egusphere-egu24-5027, 2024.

In low-permeability reservoirs, strong molecular interactions exist at the solid-liquid interface, necessitating the overcoming of the threshold pressure gradient in shale oil extraction. A profound comprehension of molecular interactions between oil and reservoir matrix is crucial to develop a productive strategy for enhanced oil recovery. Molecular dynamics simulation has become an important method for analyzing microscopic mechanisms of some static properties and dynamic processes. In this study, a molecular model of shale oil was built based on the reported experimental results and simulation. Subsequently, the molecular model was utilized to build a flow model within three matrix pores: kerogen, quartz, and portlandite. A comprehensive analysis of the interfacial effects and size effects on the threshold pressure gradient was undertaken. Emphasis was placed on elucidating the influence of the adsorption behaviors (stable adsorption, unstable adsorption, non-adsorption) of polar components at the interface on the flow of shale oil. The utilization of the critical shear stress facilitated the accurate prediction of the threshold pressure gradient of shale oil within large pores. Moreover, within the context of the flow model of shale oil in nanoscale pores, we conducted some explorations into oil displacement by CO2. This work suggests fresh ideas for studying the oil-matrix interactions on the nanoscale and provides theoretical guidance for shale oil exploitation.

How to cite: Cui, F. and Wang, F.: Micromechanical mechanism of oil-rock interaction and the availability analysis of shale oil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6006, https://doi.org/10.5194/egusphere-egu24-6006, 2024.

EGU24-6961 | ECS | Orals | ERE5.5

Nanoscale Wettability of Oil/Rock Interface and its Impact on Occurrence and Flooding 

JiaNing Fan and FengChao Wang

Mineral wettability plays a pivotal role in determining residual oil distribution and devising effective displacement strategies for enhanced oil recovery. Through molecular dynamics simulations, we investigated the surface wettability of various typical minerals, revealing the complete spreading of modeled crude oil over most mineral surfaces. Our research introduces an efficient method for calculating the spreading coefficient of modeled crude oil on mineral surfaces, allowing accurate predictions of its spreading state with a notable reduction in calculation time compared to traditional methods. Furthermore, the study explores the impact of various components within crude oil on mineral surface wettability, emphasizing microscopic interactions between these components and minerals. In nanopore channels, the diverse wettability of oil/rock interface results in varied occurrence forms, such as droplets, films, or columns, which are also different in the water flooding process. In addition, with the introduction of various components in crude oil, due to their different interactions with oil/water/rock, we found that these components can be evenly mixed with modeled crude oil or exist at the oil-water interface. Therefore, the introduction of this component changes the properties of oil-water interface, affects the form of oil occurrence and the process of flooding. These insights contribute to a comprehensive understanding of mineral surface wettability and its correlation with crude oil composition, providing valuable guidance for optimizing reservoir management and refining production strategies in the pursuit of enhanced oil recovery.

How to cite: Fan, J. and Wang, F.: Nanoscale Wettability of Oil/Rock Interface and its Impact on Occurrence and Flooding, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6961, https://doi.org/10.5194/egusphere-egu24-6961, 2024.

CO2 injection can effectively promote the development and utilization of shale oil. The interaction between CO2, shale oil and pore structure has attracted much attention as a key mechanism for oil resource exploitation. Therefore, we established a pore network model, injected shale oil and CO2 successively into the model, and studied the occurrence state of miscible fluid at the nanoscale. This study takes the shale of Lucaogou Formation in Jimsar Sag of Junggar Basin as the research object. Nano-CT and scanning electron microscopy are used to observe the pore structure of shale layer by layer, and the pore structure is transformed into a molecular model layer by layer, and finally superimposed into a pore network molecular model. Through the analysis of crude oil group components and chromatography-mass spectrometry, the characteristics of crude oil components are identified and the corresponding molecular models are established. The occurrence state of shale oil in the pore network model is simulated by molecular dynamics. CO2 is injected into the system to simulate the occurrence state of the miscible fluid. The fluid density in the system is analyzed, the interaction force between CO2, shale oil and pore structure is calculated, and the capacity models of adsorbed oil, free oil and CO2 storage are established. The reliability of the model is verified and applied by combining production data and experimental tests. This study plays a crucial role in advancing the understanding of CCUS (carbon capture, utilization, and storage) and the geological theory of shale oil and gas. It also has the potential to overcome the challenges and limitations in shale oil production technology, thus making significant contributions to this field.

How to cite: Lin, X. and Li, Z.: The mutual feedback mechanism between CO2 and multiphase fluids during CO2 injection into shale oil reservoirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8286, https://doi.org/10.5194/egusphere-egu24-8286, 2024.

EGU24-9227 | ECS | Posters on site | ERE5.5 | Highlight

Rock Reconstruction with Deep Generative Network 

Qinglong Cao and Yuntian Chen

The reconstruction of Digital Rock is a crucial challenge in understanding the microstructure of rocks and its impact on pore-scale flow through numerical modeling. This is particularly significant due to the typically large samples required to address inherent uncertainties. Despite notable advancements in traditional process-based techniques, statistical methods, and recent popular deep learning models, there is a limited focus on deep learning approaches specifically tailored for reconstructing rocks with predefined properties, such as porosity. To address this gap, our research employs Artificial Intelligence Generative Component (AIGC) technologies to precisely generate rock structures with specified properties. Our experimental results demonstrate the successful application of our method in reconstructing rock images based on target properties. The generation of randomly reconstructed samples with distinct rock properties holds promise for advancing research in pore-scale multiphase flow and uncertainty quantification in subsequent studies.

How to cite: Cao, Q. and Chen, Y.: Rock Reconstruction with Deep Generative Network, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9227, https://doi.org/10.5194/egusphere-egu24-9227, 2024.

The tight sandstone reservoir features the development of micro- and nano-scale pores and micro-fractures, contributing to a complex pore-throat structure. This complexity results in an indistinct charging sequence of oil and gas in different types of storage spaces during the accumulation period, thereby escalating the challenges associated with the exploration and development of tight oil and gas. Focusing on the Fuyu oil reservoir in the northern Songliao Basin, this study integrates large-field-of-view stitched scanning electron microscopy with mineral surface scanning techniques. Innovatively, a micro-nano scale comprehensive reservoir evaluation method, incorporating both pores and micro-fractures, is proposed. Within the study area, three predominant pore-fracture combination types are identified: intergranular pore-clay mineral shrinkage fractures, intergranular pore-brittle mineral intergranular fractures, and intragranular pore-clay mineral shrinkage fractures. Building upon this, Wood's alloy, exhibiting high-temperature rheological properties, is injected into rock cores under various pressure conditions. It is observed that with increasing injection pressure, the alloy injection process demonstrates a structured order, with a clear preference for charging intergranular pore-fractures over clay mineral-related pores. Furthermore, the alloy injection efficiency curve exhibits a distinctive parabolic shape. Based on the characteristic properties of Wood's alloy and crude oil, the injection pressure is equivalently transformed, reconstructing the micro-scale charging process of tight oil under reservoir conditions. Consequently, a sequential charging model for tight reservoirs is established, encompassing micro-nano-scale intergranular pore-fractures, nano-scale clay mineral intragranular pores, and shrinkage fractures. This model considers parameters such as source-reservoir pressure difference, storage space type, fluid properties, etc. From both qualitative and quantitative perspectives, it clarifies the microscopic accumulation sequence of tight reservoirs. This research focuses on the development of a new multi-scale evaluation method for tight reservoir storage spaces, combining fluid injection with visualization technology. The findings are crucial for the microscopic sweet spot evaluation and efficient development of tight reservoirs.

How to cite: Liu, J. and Jiang, Z.:  Investigation of Pore-Fracture Charging Sequences in Tight Reservoirs Based on Multi-Stage Pressure Injection Experiments with Wood's Alloy, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12139, https://doi.org/10.5194/egusphere-egu24-12139, 2024.

EGU24-13458 | ECS | Orals | ERE5.5 | Highlight

Machine Learning for mechanical classification of organic-rich shale based on high-speed nanoindentation 

Su Jiang, Junliang Zhao, and Dongxiao Zhang

In conjunction with scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS), quasi-static nanoindentation has been widely used to investigate the mechanical properties of minerals and organic matters in shale at micro scale. However, due to the limited test efficiency of conventional nanoindentation measurement and the demand of mineralogical identification which is achieved by SEM observation and EDS analysis, the research scheme in previous works can be time-consuming and complicated. This work attempts to develop a new micromechanical research scheme with high test efficiency and automatic mineralogical identification. A newly-developed high-speed nanoindentaion technique is used to characterize the mechanical properties distribution of a shale sample from the Yanchang Formation in the Ordos Basin, China. Then, the mineralogical distribution in the corresponding areas is obtained by using MAPS Mineralogy. Finally, logistic regression is applied to link the mechanical properties distribution and mineralogical distribution, and to realize the automatic mineralogical identification based on nanoindentation results. In addition, to further investigate the influence of characterization experiments on machine learning results, the characterization abilities, including lateral spatial resolution, detection depth, and signal spacing, of the two experimental methods are compared. The detection depth of MAPS Mineralogy is markedly higher than that of nanoindentation, which means that the material volume detected by the two methods is different. The lateral range responding to applied force and incident electrons determines that the signal of data points at the boundary can be a mixture of two or more minerals. The influence of such detection depth difference and boundary effect is also discussed.

 

 

How to cite: Jiang, S., Zhao, J., and Zhang, D.: Machine Learning for mechanical classification of organic-rich shale based on high-speed nanoindentation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13458, https://doi.org/10.5194/egusphere-egu24-13458, 2024.

    The characterization of the microscopic pore systems in organic-rich shales is crucial for comprehending the occurrence mechanisms and flow behaviors of shale oil. Although various image processing techniques have advanced the study of shale pore systems recently, challenges such as unclear boundaries of pore structures, interwoven connectivity, high similarity, and complex topological structures remain unresolved. In this study, a comprehensive investigation of the multiscale pore structure in organic-rich shale is presented, through the examination of 20 lacustrine shale samples from the Paleogene Kongdian Formation. These samples were analyzed using a variety of techniques, including N2 adsorption, mercury intrusion capillary pressure (MICP), nano X-ray CT, and Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM). Furthermore, We innovatively propose a machine learning-based multi-objective panoramic segmentation modeling method. This approach allows for precise segmentation and rapid panoramic modeling of various instances across different semantic categories and the gaps between these instances. It enables the creation of a more comprehensive multi-scale porous network model, which will be more conducive to future simulations of multi-physical processes such as fluid dynamics permeation models.
    We combine the dilated convolutions suitable for semantic segmentation with the feature pyramid structure favorable for instance segmentation to achieve precise panoramic segmentation. This approach accurately segments and represents various components in SEM images, including interparticle pores, intraparticle pores, organic pores, microfractures, feldspar, quartz, dolomite, calcite, clay minerals, and organic matter.In the three-dimensional reconstruction of FIB images, we innovatively employ registration based on contextual relationship sequences to accurately expand the reconstruction scope of pore pathways. Simultaneously, the use of an octree data structure index in constructing pore network structures enhances efficiency and speed. 
   The results show that the overall pore sizes range from 5 nm to more than 50 μm, consisting of abundant nanopores and a small quantity of micropores, and the dominant pores are in the range of 5 nm -200 nm. Through three-dimensional characterization of different types of pore networks, the transport behavior of shale oil within nanoslits was simulated, and it is proposed that fluid migration path is mainly controlled by the content of minerals, whether laminae are developed, and organic matter content. This study offers a promising solution for optimizing the automatic processing of microscopic images for pores, the combination of methods can provide pore structure characterization from sub-nanoscale to macroscale, spanning four orders of magnitude, which is crucial for improving the understanding of reservoir mechanisms and the hydrocarbon potential of lacustrine shale.

How to cite: Li, G., Xin, B., and Li, Z.: Applying Machine Learning Methods Based on Panoptic Segmentation, Context Registration, and Octree Indexing for Multiscale Pore Structure and Connectivity of the Organic-rich shales in Bohai Bay Basin, East China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19274, https://doi.org/10.5194/egusphere-egu24-19274, 2024.

EGU24-1896 | ECS | PICO | ERE5.8 | Highlight

An Integrated GNSS-SAR Approach to Improve Ground Deformation Analysis in the Field of Geo-energies: activities planned within the SMILE project 

Osmari Aponte, Andrea Gatti, Eugenio Realini, Riccardo Barzaghi, and Fernando Sansò

The SMILE network, part of the Marie Sklodowska-Curie doctoral network funded by the Horizon Europe (2021-2027) program, undertakes an innovative role in addressing geo-energy project challenges while promoting net-zero greenhouse gas emissions in line with global sustainability goals.

A segment of the SMILE network is dedicated to addressing the issue of ground deformation analysis. This research aims to develop a software tool that capitalizes on Global Navigation Satellite System (GNSS) data, coupled with Synthetic Aperture Radar (SAR) inputs and ground modeling information. This abstract outlines the methodological framework for the anticipated software development.

In the initial phase, we aim to integrate the high temporal resolution GNSS data with the high spatial resolution of SAR data. The goal of this process is to combine the advantages of both data types while minimizing their limitations. SAR provides extensive spatial detail but has limited temporal frequency and directional sensitivity. On the other hand, GNSS data provides comprehensive three-dimensional vectors with high temporal frequency, but spatially limited to the points where GNSS stations are located.

Merging the displacement measurements from GNSS and SAR requires temporal synchronization and the reconciliation of their different displacement vectors: GNSS captures vertical, east, and north components, and SAR measures in the line-of-sight direction. The optimal joint operation for this task is proposed through a Kalman filter. Due to the complexity of building a joint filter, the proposed method seeks to first analyze by considering the projected displacements only in the vertical direction. In this case, the measure in the line-of-sight of the SAR satellite will be projected in the vertical direction.

The next phase will focus on an innovative approach to enhance the covariance matrix within the Kalman filter algorithm. Instead of using a homogeneous and isotropic constant covariance in time, this enhancement strategy will harness observed data as input. Primarily, it will smooth the covariance evolution in time, exploiting past observations; this may improve the stability of the outcomes. The method under development proposes to improve the covariance modeling further by enabling the consideration of anisotropic and non-homogeneous scenarios. Finally, the proposed method aims to integrate the monitoring data into Thermo-Hydro-Mechanical (THM) modeling.

The proposed expansion is expected to bring significant advancements in ground deformation analysis, improving its resolution and precision. The tool will integrate GNSS and SAR datasets into a comprehensive ground deformation analysis suitable for geomatics applications within geo-energy projects.

How to cite: Aponte, O., Gatti, A., Realini, E., Barzaghi, R., and Sansò, F.: An Integrated GNSS-SAR Approach to Improve Ground Deformation Analysis in the Field of Geo-energies: activities planned within the SMILE project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1896, https://doi.org/10.5194/egusphere-egu24-1896, 2024.

EGU24-2815 | PICO | ERE5.8

Degradation pathways and mechanisms of oilwell cement exposed to H2S under high temperatures 

Liwei Zhang, Yue Yin, kaiyuan Mei, Xiaowei Cheng, Yan Wang, and Hanwen Wang

The extraction of geothermal energy faces the hazard of H2S, a highly toxic and strongly corrosive gas. H2S exposure can lead to the failure of oilwell cement, decreased extraction efficiency, and even pose serious risks to operational personnels near the wellsite. High temperature is a prominent environmental feature in geothermal resource extraction. However, current research works primarily focus on the corrosion effects of H2S on cement at moderate to low temperatures. This study utilizes Class G oilwell cement to conduct corrosion experiments of cement by H2S under high temperature in a H2S-rich reaction vessel. The impact of H2S on the structure, chemical composition, and mechanical strength of oilwell cement is analyzed via SEM-EDS, XRD, nanoindentation tests, and unconfined compressive strength tests. The results indicate a reduction in compressive strength for cement samples corroded by H2S. The surface nano-hardness and elastic modulus of cement samples decrease while the internal values of nano-hardness and elastic modulus significantly increase. Under the corrosion of H2S, the structure of cement is characterized by a yellow and black surface layer and stratified cracks. The external surface of the cement exhibits a yellow color due to the formation of pyrite (FeS2), while internally, pyrrhotite (FeS) and gypsum (CaSO4.2H2O) are generated.

How to cite: Zhang, L., Yin, Y., Mei, K., Cheng, X., Wang, Y., and Wang, H.: Degradation pathways and mechanisms of oilwell cement exposed to H2S under high temperatures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2815, https://doi.org/10.5194/egusphere-egu24-2815, 2024.

EGU24-3952 | PICO | ERE5.8 | Highlight

Hydrogeochemical Modeling of Opalinus Clay: Insights from CO2 Injection Experiments at Mont Terri Rock Laboratory 

Ümit Koç, Jérôme Corvisier, Dominique Bruel, and Laura Blanco Martin

Within the context of CO2 injection, understanding the properties of potential caprocks, particularly clay-rich ones such as Opalinus Clay and their potential evolution is crucial for safe and effective carbon capture and storage (CCS) initiatives. This study presents hydrogeochemical models developed to investigate interactions between groundwater, Opalinus Clay caprock and CO2, focusing on chemical evolution under varying pCO2 levels across different layers of the clay.

Utilizing a comprehensive dataset derived from CO2 injection experiments conducted at the Mont Terri Rock Laboratory and published pore water chemistry of Opalinus Clay, hydrogeochemical models of a potential reservoir and caprock system were constructed employing PHREEQC and CHESS geochemical modeling softwares. These models were designed to simulate and comprehend the intricate processes governing groundwater-CO2-rock interaction within the reservoir-caprock interface and through the stratified layers of Opalinus Clay.

The models aimed to elucidate the chemical evolution of the groundwater as it interacts with the Opalinus Clay under different pCO2 conditions. By considering variations in pCO2 levels representative of potential CCS scenarios, the simulations provided insights into the geochemical alterations occurring within the caprock and their implications for its integrity over time.

The findings of these hydrogeochemical models offer valuable insights into the potential consequences of CO2 injection into reservoirs whose caprocks are formed of Opalinus Clay, informing risk assessment and mitigation strategies for CCS applications. Moreover, these constructed hydrogeochemical models not only serve as a crucial foundation for comprehending the intricate thermal-hydro-mechanical-chemical (THMC) coupling mechanisms within caprocks like Opalinus Clay but also contribute to a deeper understanding of the complex interplay between pore water chemistry, rock properties, and varying pCO2 levels, essential for ensuring the long-term security and effectiveness of subsurface CO2 storage.

How to cite: Koç, Ü., Corvisier, J., Bruel, D., and Blanco Martin, L.: Hydrogeochemical Modeling of Opalinus Clay: Insights from CO2 Injection Experiments at Mont Terri Rock Laboratory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3952, https://doi.org/10.5194/egusphere-egu24-3952, 2024.

In the realm of harnessing geothermal energy, groundwater heat pumps exhibit superior thermal efficiency when compared to closed-loop geothermal heat pumps. However, the outlook for progress remains less than promising. A primary obstacle stems from the improper extraction of groundwater, which can disrupt the stress field in subsurface structures and potentially trigger land subsidence. This concern is particularly pronounced in unconsolidated soils found in coastal sedimentary plains, where the additional threat of severe flooding disasters looms. Furthermore, artificial pumping processes may give rise to coupled hydraulic phenomena, exemplified by the reverse water level fluctuations. This transient anomalous changes in hydraulic head occurs in adjacent aquifers during the initial stages of pumping from a confined aquifer, induced by strain propagation. The magnitude of the hydraulic head elevation varies from a few centimeters to several tens of centimeters, posing a challenge to the accurate interpretation of groundwater monitoring data for land subsidence prevention. Geothermal heat pump systems can also induce changes in the temperature and thermal strain of geological layers. Consequently, understanding how this strain-induced hydraulic head responds to temperature fluctuations becomes a research question. In our investigation, the hydraulic and mechanical responses of a three-layer aquifer system to groundwater pumping were assessed through thermoporoelastic numerical simulations. The simulated reverse hydraulic head changes align with field observations documented in the literature. The findings of this numerical investigation indicate that when we recharged the water into the ground, the initial head decrease is likely to occur in proximity to a recharge well within an unpumped clay layer. These deformation-induced head changes eventually dissipate following the hydraulic propagation of unsteady state drawdown from the pumped aquifer into adjacent layers. In the event of reverse water level fluctuation, it is shown that temperature has no obvious influence on the hydraulic variation, both the head variation and happening time. It is also suggested that the propagation of thermally induced strain is slower than that of hydraulically induced strain and the effect appears much later.

How to cite: Yue, L. and Aichi, M.: Numerical Investigation of Reverse Water Level Fluctuations under Non-Isothermal Conditions with a Fully Coupled Thermal-Hydro-Mechanical Model for Geothermal Heat Pump Systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5401, https://doi.org/10.5194/egusphere-egu24-5401, 2024.

EGU24-5492 | PICO | ERE5.8

A Neural Network to Reduce Subsurface Uncertainty Based on Ground Deformation Measurements 

Tian Guo, Haiqing Wu, and Víctor Vilarrasa

Subsurface uncertainty is large because we have limited access to it. Reducing uncertainty is important for geo-energies in order to increase the reliability of the simulation results used to define safe operation conditions. In particular, subsurface uncertainty can be reduced by analyzing ground deformation. A clear example of this is the CO2 storage project at In Salah, Algeria, where a double lobe ground deformation shape revealed the presence of a vertical fault zone at depth. Here, we propose a workflow to reduce subsurface uncertainty by inferring the subsurface characteristics from ground deformation measurements. As a foundation step of the workflow, we train a supervised neural network-based regression approach for predicting ground deformation caused by reservoir pressurization due to fluid injection. To train the neural network, we use a recently developed analytical solution to assess ground displacement in response to pressurization of a reservoir that is intersected by a permeable or an impermeable fault (https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4503451). The instantaneous solution provided by the analytical solution allows us to generate a large dataset to train the neural network. We have varied eleven variables, including fault and reservoir geometry and mechanical properties. Simultaneously, a simplified parametric space analysis is also performed. Results show that the reservoir thickness, Biot´s coefficient, and the pore pressure buildup impact the displacement the most. This study highlights that an appropriately trained neural network can effectively predict the ground deformation and give insights into the corresponding subsurface characteristics.

How to cite: Guo, T., Wu, H., and Vilarrasa, V.: A Neural Network to Reduce Subsurface Uncertainty Based on Ground Deformation Measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5492, https://doi.org/10.5194/egusphere-egu24-5492, 2024.

EGU24-6245 | ECS | PICO | ERE5.8

Improving PSI Capabilities on Ground Deformation Monitoring for The Application of Geo-Energy Projects.  

Maria Carmelia Ramlie, Paula Olea-Encina, Michele Crosetto, and Oriol Monserrat

PSI Technique remains a powerful remote sensing method in terms of ground deformation monitoring, which makes it useful for monitoring geo-energy projects such as geothermal and CO2 sequestration where movement is always detected. The monitoring is a crucial supporting component to ensure the smooth progress of geo-energy development. However, PSI Technique still faces some problems that affects the accuracy of the detection. This can be caused by data and related to the terrain of the study areas, such as vegetation, buildings, and the direction of the ground deformation. The goal is to counteract this is by combining multiple sensor images, both low resolution and high resolution. These can be obtained from the wide range of satellites available today such as Sentinel-1, TerraSAR, COSMO-SKYMED, and NISAR. This technique is supposed to increase the temporal sampling for a more comprehensive time series, redundancy to improve accuracy and robustness of PSI analysis, wider coverage by exploiting at each site the data that offers best performances. Aside from the expected improvement, some challenges in developing this technique will be presented. Most of the challenges are due to the difference in satellites’ characteristics, such as resolution, pixel spacing, wavelength, and geometry. The technique is planned to be applied on several study areas. The purpose of this is to study the effects of different terrain characteristics on the re-sampling process, tuning processes, and the result of the processing. One of the study areas will serve as the benchmark of the research.

How to cite: Ramlie, M. C., Olea-Encina, P., Crosetto, M., and Monserrat, O.: Improving PSI Capabilities on Ground Deformation Monitoring for The Application of Geo-Energy Projects. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6245, https://doi.org/10.5194/egusphere-egu24-6245, 2024.

EGU24-6264 | ECS | PICO | ERE5.8

Relationship between Environmental Factors and Radar Amplitude: Illinois Basin – Decatur Project case study 

Paula Olea-Encina, Maria Carmelia Ramlie, Oriol Monserrat, and Michele Crosetto

2023 was claimed as the beginning of the “Global Boiling Era”. For this reason, geo-energies are key to provide a green and clean future. Geothermal energy, and geologic carbon injection/storage are the main types of geo-energies. Both have in common the underground fluid movement and the consequent ground motion dynamics.

One of the main techniques for analyzing ground motion is Persistent Scattered Interferometry (PSI), which allows us to estimate ground deformation over time from radar satellite data. PSI techniques calculate the temporal displacement in the so-called persistent scatterers by filtering the data based on amplitude value. Generally, the main cause for amplitude variability is the change in the surface properties over time, primarily due to changes in environmental factors (land cover/land use, vegetation dynamics, temporal water presence, or soil moisture). The main concern with these changes is that they may result in phase shifts, which could be misinterpreted as range displacements.

Improving the understanding of the environmental factors could improve the understanding of ground deformation over time. Therefore, environmental factors analysis and PSI can be integrated seamlessly into a workflow since the launch of the Copernicus Programme, combining Sentinel-1 and Sentinel-2 data. The goal of this research is to explore the relationship between environmental variables and amplitude values. This research is framed in the MultidiSciplinary and MultIscale approach for assessing coupLed processes induced by geo-Energies (SMILE) Project. The study site is the Illinois Basin – Decatur Project (IBDP), which is a carbon dioxide injection and storage located in the United States. IBDP is in the north part of Decatur city, the vegetation is mainly woodland and prairie; with a humid subtropical climate, with an annual precipitation over 1000 mm.

The analysis focuses on three areas near IBDP: wetland area, crop area, and woodland area. Performing a spatio-temporal analysis of the vegetation index (NDVI), soil moisture index (NDWI), and temporal water presence (NDWI) obtained from Sentinel-2 data between 2015 to 2023 and comparing these datasets with the amplitude time series from Sentinel-1 imagery for the same period. The results show that the woodland area has a high mean amplitude value with low dispersion; the wetland area has a low mean amplitude value with high dispersion; and the crop area has a medium mean amplitude value with medium dispersion.

The vegetation index for the woodland area has 7 month per year values over 0,4, showing a presence of high photosynthetic activity, which can be related to the low value of dispersion amplitude; while the wetland area only 3 months per year has a value over 0,4, that can be source of the high dispersion amplitude. While the crop area is 6 months over the threshold. The results of the analysis performed showed that the use of environmental indices can help in the interpretation of the dispersion amplitude in the PSI analysis. The next step is to consider more environmental variables such as snow cover, land cover/land use, or temperature in the analysis of amplitude, as well as consider different polarizations, among others.

How to cite: Olea-Encina, P., Ramlie, M. C., Monserrat, O., and Crosetto, M.: Relationship between Environmental Factors and Radar Amplitude: Illinois Basin – Decatur Project case study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6264, https://doi.org/10.5194/egusphere-egu24-6264, 2024.

EGU24-7497 | ECS | PICO | ERE5.8

Decay of seismic noise at shallow boreholes: Observations from Groningen. 

Oleh Kalinichenko, Leo Eisner, Frantisek Stanek, Umair Waheed, Sherif Hanafy, and Zuzana Jechumtalova

Long-term seismic monitoring arrays are often deployed to shallow boreholes to reduce the seismic noise. We investigate noise level decay in shallow boreholes. A large number of publicly available data with such deployment is available at the seismic monitoring array near the town of Groningen, which allows also characterization of the seismic noise decay in shallow boreholes in urban environments. We study noise distribution at 4 sites from this array. Each site includes 5 receivers deployed in shallow vertical boreholes with 50 meters intervals between the surface and 200 m depth. We show there is no difference between noise levels during the summer and winter at the borehole instruments. However, we observe diurnal variation at all depth levels. We also show there are higher noise levels throughout weekdays and lower during weekends and state holidays. These changes are not only observed at the surface but also at the deepest receivers. This implies that the dominant source of this noise is anthropogenic and it penetrates to depths of 200 meters even at frequencies exceeding 5 Hz. This observation is contradicting the common assumption that the seismic noise consists of the surface waves.

How to cite: Kalinichenko, O., Eisner, L., Stanek, F., Waheed, U., Hanafy, S., and Jechumtalova, Z.: Decay of seismic noise at shallow boreholes: Observations from Groningen., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7497, https://doi.org/10.5194/egusphere-egu24-7497, 2024.

EGU24-8100 | PICO | ERE5.8 | Highlight

CO2 storage in saline aquifers: multi-scale processes visualized using the Sleipner case 

Tae Kwon Yun, Mateja Macut, Katja Schulze, Philip Ringrose, and Carl Fredrik Berg

Injection of dense-phase CO2 in a saline sandstone aquifer involves several processes which ideally work together to ensure effective long-term storage. The main processes are flow of free-phase CO2 (controlled by viscous and gravity forces), residual trapping at the pore scale, structural trapping at the scale of geological heterogeneities and dissolution in the aqueous phase.  Assessment of possible lateral and vertical migration along high-permeability layers or faults and fractures will also require stress-sensitive flow models which consider the phase behaviour of CO2, and the associated coupled thermal-hydraulic-mechanical-chemical processes.
Many insights into these complex processes can be obtained by analysis of the time-lapse seismic data at Sleipner CO2 storage project in Norway, in conjunction with findings derived from the quantitative and qualitative uncertainty analysis of the medium-scale flow experiments at the Mont Terri Rock Laboratory (Switzerland), involving periodic injections over long-term (CO2LPIE). The insights at Sleipner include the effects of internal shale layers and shale breaks in controlling the actual multi-layer CO2 distributions, the likely contribution of different of trapping mechanisms and the effectiveness of the overlying caprock. Another set of insights gained from these data are estimates of the effective use of the pore space at different length scales. The seismic imaging datasets can be used to show that at the scale of whole storage unit the overall storage efficiency is in the range of 2-5%, with the result depending very much on how the storage volume is defined. When the effects of areal and vertical sweep efficiency are considered, the fraction of the pore space occupied by CO2 rises to around 40-50%.
We illustrate these multi-scale processes using seismic data, analytical analysis, example flow models and 3D/4D visualization. Use of Invasion Percolation (IP) flow models is contrasted with multiphase (finite difference) flow simulators. With this approach CO2 migration problems will be addressed, as well as various open-source research codes will be used to develop enhancements for handling fluid mixing between hydrocarbon and CO2 phases in brine-saturated media. Moreover, coupled thermal modelling is found to be important at this site due to significant temperature changes as the CO2 plume expands and rises within the formation. Next to classic PC screen display, we empower the visualization by using the extended reality (XR) platform for geoscience, BaselineZ. This allows for true 3D (holographic) display in virtual reality (VR) as well as remote and interactive collaboration around the Sleipner dataset and thus leads to new insights. 

How to cite: Yun, T. K., Macut, M., Schulze, K., Ringrose, P., and Berg, C. F.: CO2 storage in saline aquifers: multi-scale processes visualized using the Sleipner case, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8100, https://doi.org/10.5194/egusphere-egu24-8100, 2024.

EGU24-10213 | PICO | ERE5.8

How THM Changes in Layered Geological Systems Influence Stability of Fractured Networks 

Anas Sidahmed and Christopher Mcdermott

Various geo-energy applications such as geothermal energy, Carbon Capture and Storage (CCS) and underground heat storage are some of the technologies leveraged to realize Paris Agreement goals by cutting greenhouse gases emissions (GHG). However, these applications require in-depth understanding of the effect of coupled Thermal, Hydraulic, Mechanical and Chemical (THMC) processes that take place in the deep subsurface geological layers. This study focuses on the modeling of THM coupled processes in heterogeneous layered reservoirs.

When geological heterogeneities exist in the subsurface, each layer will have its own thermal, geomechanical and geological properties such as thermal conductivity, thermal expansion coefficient, porosity, permeability, Young’s modulus, Poisson’s ratio and so on. These variations in the properties add more complexity to the behavior of coupled THM processes of the system, which in turn requires sophisticated modeling approaches. To reduce complexity, the subsurface layers can be bundled into groups called “geomechanical facies” based on the mentioned material properties from THM characteristics perspective.

The work in this paper is based on key generic features of actual geo-energy applications where simulation modeling has been utilized to demonstrate how coupled THM processes are affected in heterogenous layers compared to homogenous layers. Hypothetical heterogenous layers have been divided into sets of distinct geomechanical facies. OpenGeoSys (OGS) open-source Finite Element based THMC code was utilized to build the run simulation models.

The results demonstrate that variations in the rock thermal, hydraulic and mechanical properties among different neighboring layers have a significant and individually different impact on stress mapping and distributions in addition to strain transfer to the surface. Geomechanical stability of the system parts that are more prone to failure such as fractures and faults were assessed using Factor of Safety (FOS) analysis which are based on stress distribution and rock mechanical properties. Results suggest that geological heterogeneity has more significant impact on hard rocks compared to soft rocks. The latter (i.e., soft rocks) have the ability to maintain sealing capability of caprocks because they are more ductile and have more room for further deformation prior to failure.

The simulation modeling results in this study contributes to the understanding of the key THM processes involved in heterogenous layered systems. Furthermore, this work provides valuable insights towards developing more generic design criteria and predictive models for various geo-energy applications which can be tailored and used in the design of the particular systems.

How to cite: Sidahmed, A. and Mcdermott, C.: How THM Changes in Layered Geological Systems Influence Stability of Fractured Networks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10213, https://doi.org/10.5194/egusphere-egu24-10213, 2024.

EGU24-17949 | ECS | PICO | ERE5.8

Modelling coupled hydro-mechanical processes of gas flow in the Opalinus Clay 

Matthijs Nuus, Antonio Pio Rinaldi, Robert Cuss, Manuel Sentis, Jocelyn Gisiger, Bastian Graupner, Fabiano Magri, Frederic Bernier, and David Jaeggi

Deep geological repositories rely on a natural geological barrier with a low permeability to ensure radioactive waste containment and prevent radionuclide transport into the biosphere. For the Swiss repository concept, the Opalinus Clay formation is considered as the natural geological barrier. After high-level radioactive waste are disposed of in a repository within the host-rock, corrosion of metal containers in anaerobic conditions can result in the release of hydrogen. Due to the low-permeability of the host-rock, elevated gas pressures are expected. If the gas pressure exceeds the minimum principal stress, fracturing of the rock could occur. It is therefore important to assess the possible impacts of this process on the integrity of the repository such as a possible increase of the permeability of the host formation.

Production of hydrogen is anticipated to span more than 100,000 years, and understanding how gas transport occurs in a low-permeable host-rock is therefore an important aspect for the long-term safety of the repository. Gas transport can generally be subdivided in four different mechanisms: (1) advective-diffusive flow, (2) visco-capillary two-phase flow, (3) dilatancy-controlled gas flow and (4) gas transport along macroscopic tensile fractures. Gas flow rate and the microstructure of the host rock largely control the dominating gas transport mechanism, but the exact variables determining the process are poorly quantified.

The GT (Gas Transport) experiment at Mont Terri was designed to study the pressure and deformation effects after injecting gas into the Opalinus Clay. Helium was injected with increasing pressure increments until a gas breakthrough was observed. The borehole into which the helium was injected was surrounded by eight observation boreholes providing deformation and pore pressure observations.The results of the experiment have been used to create a coupled hydro-mechanical model using TOUGH-FLAC, which couples the multiphase flow and heat transport simulator TOUGH3 with the geomechanical simulator FLAC3D. The model uses the helium injection rates as input and computes the resulting pressure and deformation responses. By running models with different transport mechanisms (e.g. two-phase only, both two-phase and dilatancy, allowing fracture formation) and by comparing the pressure and deformation results with the observations, insight is gained into the dominant transport mechanisms in the Opalinus Clay. Preliminary results reveal a slow build-up of strain and a relatively small pressure drop after gas injection begins, suggesting that dilatancy-controlled gas flow occurred.

How to cite: Nuus, M., Rinaldi, A. P., Cuss, R., Sentis, M., Gisiger, J., Graupner, B., Magri, F., Bernier, F., and Jaeggi, D.: Modelling coupled hydro-mechanical processes of gas flow in the Opalinus Clay, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17949, https://doi.org/10.5194/egusphere-egu24-17949, 2024.

EGU24-18589 | ECS | PICO | ERE5.8

Investigating the Effect of Fracture Properties on Peclet Number of Enhanced Geothermal Systems 

Khashayar Khezri, Emad Jahangir, Dominique Bruel, and Murad Abuaisha

Understanding heat transfer mechanisms in subsurface environments is crucial for deep geothermal energy exploitation. Despite multiple studies on heat transfer in porous media, the combination of different heat transfer mechanisms with fracture networks leads to uncertainty in the temperature distribution in geothermal sites.

More specifically, heat convection and conduction are two major mechanisms responsible for heat transfer in porous media. Conduction occurs through rock matrix and is more dominant than convection in intact rocks due to their low porosity. However, fracture networks in rocks increase fluid transfer in certain directions, making convection more important in heat transfer. At a certain point, it becomes difficult to identify which mechanism is more prevalent. Besides this difficulty, achieving a balance between these two key mechanisms and determining the optimal Peclet number is very crucial for the geothermal energy industry to extract adequate volume of water at the desired temperature, which is essential for smooth operation of geothermal systems. In this study, a two dimensional coupled thermo-hydraulic model in COMSOL is developed to simulate heat transfer mechanisms in enhanced geothermal systems on field scale. Characteristic time variables based on hydraulic and thermal diffusivities are defined to monitor heat distribution through the domain caused by each mechanism. Finally, a sensitivity analysis is performed to identify how the temperature is affected by rock (thermal and hydraulic) parameters and fracture patterns. The simulation results indicate that the Peclet number is highly dependent on fracture network.

How to cite: Khezri, K., Jahangir, E., Bruel, D., and Abuaisha, M.: Investigating the Effect of Fracture Properties on Peclet Number of Enhanced Geothermal Systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18589, https://doi.org/10.5194/egusphere-egu24-18589, 2024.

EGU24-18886 | ECS | PICO | ERE5.8 | Highlight

Multi-scale study on fluid-rock interaction in caprock and reservoir rocks for enhanced CO2 sequestration 

Prescelli Annan, Claudio Madonna, Antonio Pio Rinaldi, and Alba Zappone

In the context of geological CO2 sequestration, understanding the complex interaction between reactive fluids and the rock matrix is pivotal in efficient and safe carbon storage. This paper presents a recently initiated research plan, spanning laboratory and pilot scale, covering two main scenarios: A) reactive reservoir rocks (e.g. basalt and peridotite), and B) claystone saline aquifers with sandstone reservoir rocks and claystone caprock. To investigate the specific effects of CO2 exposure on rock properties, we propose a 1-2 year exposure experiment on intact rock core samples. The experiment will be conducted using a batch reactor system equipped with continuous pH monitoring and carefully controlled to replicate in situ salinity, pressure and temperature levels. Before, during and after exposure, samples will be analysed using CT scanning to detect changes in porosity, and mechanical and physical properties will be assessed before and after exposure. Preliminary characterisation of the cores prior to exposure to CO2 will also be presented.

In parallel decameter scale experiments spanning many months of CO2 injection are conducted at the Mont Terri underground rock laboratory in Switzerland. The experiments involve observing the injection of CO2-saturated brine into a fault zone within Opalinus Claystone—an analogue caprock. This contributes to a more comprehensive understanding of fluid injection on fault reactivation, particularly within the context of leakage processes at shallow depths crucial to CO2 storage security. Preliminary results on clay deformation in response to rapid increase of injection pressure will be presented.

This research plan aims to understand reactive processes in different geological contexts fundamental to carbon storage strategies. Operating at multiple scales - from laboratory to pilot scale analysis - our study aligns with the session's broader goal of advancing the understanding and predictive capabilities of coupled processes induced by geoenergy applications. By sharing preliminary results and fostering collaboration, we aspire to maximise the scientific results of our laboratory experiments and contribute to the scientific community's search for sustainable solutions in carbon storage strategies.

How to cite: Annan, P., Madonna, C., Rinaldi, A. P., and Zappone, A.: Multi-scale study on fluid-rock interaction in caprock and reservoir rocks for enhanced CO2 sequestration, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18886, https://doi.org/10.5194/egusphere-egu24-18886, 2024.

EGU24-589 | ECS | Orals | EMRP1.2

Verification of susceptibility and density relationship from 3D joint inversion of airborne magnetic and gravity data in northern Victoria Land, East Antarctica, with petrophysical measurements 

Maximilian Lowe, Tom Jordan, Max Moorkamp, Jörg Ebbing, Nikola Koglin, Antonia Ruppel, Chris Green, Jonas Liebsch, Mikhail Ginga, and Robert Larter

Subglacial geology remains largely unknowns in Antarctica. Direct geological samples are limited to ice free regions along the coast, high mountain ranges or isolated nunataks, while the origin of geological material transported by glaciers themselves is often ambiguous. 3D singular and joint inversions of airborne gravity and magnetic data recovers subsurface density and susceptibility distribution. The relationship between both inverted petrophysical quantities provide crucial insight for subglacial geology and rock provinces interpretations. Validation of indirect derived subglacial geology models are critical but very challenging in Antarctica due to the sparsity of rock samples.

We present 324 new density and susceptibility measurements on rock samples from Northern Victory Land, East Antarctica. 251 samples have been measured at the National Polar Sample Archive (NAPA) from the Federal Institute for Geosciences and Natural Resources (BGR) in Berlin-Spandau, Germany and additional 73 samples were measured at the BGR in Hannover, Germany. We use the petrophysical measurements to validate our recent regional scale 3D joint inversion model of the Wilkes Subglacial Basin and the Transantarctic Mountains. Furthermore, we validate inversion results on a local scale of singular magnetic inversion based on high resolution airborne magnetic data with a flight line spacing of 500m in the Mesa Range.

We demonstrate that we can provide reliable discrimination between Ferrar Dolerites, Kirkpatrick Basalt and Granite Harbour intrusion rocks based on our local inversion model and that the recovered susceptibilities agree with those measured at rock samples from the study area. Furthermore, we show that regional scale inversion model of gravity and susceptibility distribution agrees for samples of the dominant crustal rock types. However, densities of small-scale dense intrusion bodies like Ferrar Dolerites are underestimated by the regional scale inversion, while the susceptibility range is correctly recovered.

Constraining subglacial geology with joint inversion of airborne potential field data is heavily depended on the resolution of the airborne survey, flight line coverage, the inversion scale, and the scale of the target feature. Regional scale inversion is adequate for large scale geological heterogeneities, which underestimate petrophysical quantities for small scale structures, while local scale inversions are able to resolve such structures but are more computational demanding and in the case of Antarctica lack ultra-high resolution airborne gravity data with a line spacing below 1000 – 500m.

How to cite: Lowe, M., Jordan, T., Moorkamp, M., Ebbing, J., Koglin, N., Ruppel, A., Green, C., Liebsch, J., Ginga, M., and Larter, R.: Verification of susceptibility and density relationship from 3D joint inversion of airborne magnetic and gravity data in northern Victoria Land, East Antarctica, with petrophysical measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-589, https://doi.org/10.5194/egusphere-egu24-589, 2024.

EGU24-974 | ECS | Posters on site | EMRP1.2

Dynamic Compressive Strength of Thermally Treated Barakar Sandstone 

Adarsh Tripathi, Mohammad Mohsin Khan, Nachiketa Rai, and Anindya Pain

Assessing the thermal influence on the dynamic mechanical properties of Barakar sandstone is crucial, notably in the examination of subsidence phenomena induced by underground coalmine fires in tandem with blast-induced loading. The Jharia region had been affected by underground coalmine fires, resulting in surface fracturing on both small and large scales. So, the objective of the study is to examine the impact of high temperature on the dynamic compressive strength of colliery sandstone subsurface samples, and its correlation with the mineralogical properties. To accomplish this objective, samples were subjected to a 24-hour heat treatment in a furnace at a controlled heating rate of 5°C/min, followed by natural cooling within the furnace. The samples were divided into five groups, each undergoing different thermal treatments at temperatures of 25°C, 200°C, 400°C, 600°C, and 800°C. The dynamic compressive strength was obtained by performing the dynamic compression tests on Split Hopkinson Pressure Bar setup. The results clearly indicate that up to a critical temperature i.e. 400°C, both quasi-static and dynamic compressive strength showing the minor strengthening effect. However, beyond this critical temperature, there is a significant decrease in strength, particularly up to 800°C. Additionally, for each temperature, the dynamic strength also exhibits an increasing trend with increase in strain rate. The study investigated the applicability of the Kimberley Theoretical Universal Scaling Law in predicting the dynamic compressive strength of thermally treated sandstone across different strain rates. Furthermore, it pinpointed the characteristic strain rate at which the dynamic compressive strength of thermally treated sandstone doubled in comparison to its quasi-static compressive strength.

How to cite: Tripathi, A., Khan, M. M., Rai, N., and Pain, A.: Dynamic Compressive Strength of Thermally Treated Barakar Sandstone, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-974, https://doi.org/10.5194/egusphere-egu24-974, 2024.

EGU24-1531 | ECS | Orals | EMRP1.2

Outcrop analogue study of carbonate caprock stringers for CCS and geothermal reservoir: the petrophysical and petrothermal properties of the upper Muschelkalk in the Estopanyà salt wall (South-Central Pyrenees) 

Pedro Ramirez-Perez, Gabriel Cofrade, David Cruset, Irene Cantarero, Juan Diego Martín-Martín, Oriol Ferrer, Jean-Pierre Sizun, and Anna Travé

Salt is playing a principal role in the current energy transition. From diapirs to salt walls, salt structures are being proposed for a growing number of non-fossil energy purposes and carbon-neutral projects (i.e., geothermics, hydrogen storage in salt caverns or CCS). However, diapiric structures are not uniform and exhibit significant compositional and structural heterogeneities that prevent an easy characterization and exploration, thus increasing the risk of exploitation. Compositional heterogeneities within salt structures arise by the occurrence of different rocks inherited from the original Layered Evaporite Sequence (LES) and transported during salt flow or created through various diagenetic processes during diapirism (e.g., caprock formation).

One of the most common heterogeneities found in salt bodies is the presence of heterometric rock masses known as stringers. The limestones of the upper Muschelkalk (M3) facies (Middle Triassic) are the primary non-evaporitic lithological unit within the Triassic LES of the South-Central Pyrenees. These limestones are exposed throughout the South-Pyrenean fold-and-thrust belt embedded in mudrocks and gypsums of the Upper Triassic Keuper facies, forming the actual caprock exposures in the region. The Estopanyà salt wall is located in the westernmost part of the South-Central Pyrenean Zone, within the Serres Marginals thrust sheet. This area shows a well-preserved 58 km2 caprock exposure formed by Middle and Upper Triassic rocks that surround two adjacent salt-embedded basins known as the Estopanyà and Boix synclines. According to the stratigraphic record of these synclines, from the Upper Cretaceous to the Oligocene, the evolution of the area resulted in salt withdrawal leading to salt inflation and the occurrence of several E-W-oriented salt walls that were exposed during the deformation onset in the Lower Eocene (early Ypresian times).

The M3 stringers in the Estopanyà salt wall are embedded in a caprock matrix formed by the dissolution of halite on the surface, albeit its presence has been proposed at deeper levels based on gravimetric models. The stringers have been identified and mapped, forming decameter-thick and kilometre-long structures showing significant folding and fracturing as well as a well-preserved stratigraphic sequence. The basal part of these stringers is formed by a layered to tabular millimetre-to-centimetre-thick limestones whilst the upper part consists of tabular to massive centimetre to meter-thick limestones. The current contribution presents the petrophysical (i.e., mineral density, connected porosity, permeability and P-wave velocity) and petrothermal (thermal conductivity and specific heat capacity) properties of 40 samples collected throughout the eastern Estopanyà salt wall, covering the basal and upper succession of various stringers. The sample analysis enables us to discuss the factors controlling the studied rock properties and the viability of carbonate stringers as geothermal reservoirs and CCS, which is a novel study that can be replied in similar salt structures worldwide.

How to cite: Ramirez-Perez, P., Cofrade, G., Cruset, D., Cantarero, I., Martín-Martín, J. D., Ferrer, O., Sizun, J.-P., and Travé, A.: Outcrop analogue study of carbonate caprock stringers for CCS and geothermal reservoir: the petrophysical and petrothermal properties of the upper Muschelkalk in the Estopanyà salt wall (South-Central Pyrenees), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1531, https://doi.org/10.5194/egusphere-egu24-1531, 2024.

Tracking CO2 transport in subsurface rock during geological carbon sequestration has received significant attention. Although X-ray computed tomography (XCT) imaging techniques, visualization and quantification of CO2 behavior has been undertaken by previous researchers, little attention has been given to the nature of CO2 transport in a reservoir-caprock interface with well-developed pores in the reservoir and micro-fractures in the caprock. As the transition of two different pore systems, this complex system is crucial in controlling the sequestration safety case. We have used advanced time-lapse synchrotron imaging at in-situ pressure and temperature conditions to image the CO2 transport process in such an experimental system, for both gaseous and supercritical phases.

Dynamic XCT images of fluids and the pore- and fracture-system in the mudstone and sandstone couplet were acquired at high resolution (effective voxel size 1.625 µm). Strain maps following high-speed gaseous and supercritical CO2 (ScCO2) flooding were modelled using a digital volume correlation (DVC) method to reveal the hydro-mechanical effects. The results suggest that under the influence of brine, high-speed gaseous CO2 will not increase the total pore-throat volume and can even cause a reduction in permeability in sandstone due to fines migration induced by CO2 flooding. Clay behavior, notably dispersion in brine, migration of fines and swelling induced by CO2, plays a notable role in the opening and closing of pores/fracture. Fluid breakthrough occurred at 10.6 MPa during high-speed ScCO2 injection. The significant fracturing effect of high-speed ScCO2 resulted in the connection of natural fractures in the mudstone with newly developed secondary branches and also created larger pore space in the sandstone, leading to an increase in porosity by approximately 2.8 times in the mudstone and 1.6 times in the sandstone. Additionally, there was an approximate increase of 2.6 times and 8.6 times in the permeability of mudstone and sandstone, respectively, after CO2 phase transition. The concentrated strains around the main fracture in the mudstone and web-like strains around the boundary of granular minerals in sandstone show the different modes of action of ScCO2 when passing through a reservoir rock and caprock system. This work is of practical significance in improving understanding of CO2-fluid-rock interaction in a complex reservoir-caprock system.

How to cite: Taylor, K., Wang, K., and Ma, L.: 4D synchrotron imaging of CO2 transport in reservoir rocks and caprocks: Informing safe CO2 sequestration    , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1866, https://doi.org/10.5194/egusphere-egu24-1866, 2024.

EGU24-3448 | ECS | Posters on site | EMRP1.2

Quantifying the influence of the type and arrangement of conductive phases on the electrical properties of rocks using impedance spectroscopy  

Hadiseh Mansouri, Virginia Toy, Kevin Klimm, Sören Tholen, and Friedrich Hawemann

We have employed impedance spectroscopy to investigate the impact of chemical composition and microstructure on the electrical properties of geological samples. Our study focused on a metapelite sample containing graphite, extracted from a depth of 530 meters in borehole DT-1B as part of the DIVE (Drilling the Ivrea-Verbano zonE) project in Ornavasso, Italy. Additionally, we examined the electrical properties of synthetic mineral assemblages. These were created by combining quartz powders with variable amounts of graphite (1% and 5% by weight), muscovite (5% by weight), and biotite (5% by weight). The goal was to identify which conductive or semiconductive phases predominantly influenced the electrical behavior of the metapelite. Measurements were conducted using a Solartron-1260 Impedance/Gain-Phase Analyzer within a piston cylinder apparatus. The experiments were carried out at a pressure of 500 MPa, temperatures ranging from 22 to 1000 °C, nominally dry conditions, and across a frequency range from 0.1 Hz to 200 kHz.

All samples exhibited high electrical resistance (R > 106 Ω.m), low electrical conductivity (< 10-6 S/m) and behaved as capacitors, with a phase angle magnitude exceeding 70° for most frequency ranges at temperatures below 200 °C. A representative impedance spectrum (Nyquist plot) illustrates this behavior through a partial semicircular arc originating from the origin. An inverse relationship between electrical conductivity and temperature was observed in almost all samples when temperatures increased from 300 to 500 °C. This phenomenon is attributed to the presence of open grain boundaries in the samples, leading to electrical charge scattering. Notable variations in electrical behavior were observed at temperatures exceeding 600 °C, including a linear increase in electrical conductivity, changes in Nyquist plots such as a reduction in prominence of the ‘grain interior arc’ and an increase in significance of the ‘grain boundary arc’, a decrease in sample capacitance, and a significant decline in the phase angle's frequency dependency. Microstructural analysis reveals that these changes were associated with dehydration melting of mica in mica-bearing samples and the growth and interconnection of graphite grains in graphite-bearing samples. Variations in activation enthalpy with temperature suggested that impurity conduction and small polaron hopping played a crucial role at lower temperatures, while the diffusion of H and alkali ions (in mica-bearing samples) or carbon (in graphite-bearing samples) along grain boundaries became significant at higher temperatures.

The natural metapelite sample exhibited electrical conductivities similar to the quartz + 5% graphite sample at high temperatures, reaching 10-1.5 S/m at 1000°C. This is comparable to the conductivity levels typically measured by magneto-telluric (MT) surveys in Earth's crust.

How to cite: Mansouri, H., Toy, V., Klimm, K., Tholen, S., and Hawemann, F.: Quantifying the influence of the type and arrangement of conductive phases on the electrical properties of rocks using impedance spectroscopy , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3448, https://doi.org/10.5194/egusphere-egu24-3448, 2024.

EGU24-3734 | ECS | Posters on site | EMRP1.2

Spatio-Temporal Imaging of Instability and Transport of Pickering Nanodroplets in Porous Media 

Boxin Ding, Seyedeh Hannaneh Ahmadi, Steven Bryant, and Apostolos Kantzas

Featuring a large specific surface area with associated high reactivity, nanomaterials in various morphologies are ideal candidates for improved oil recovery (IOR), enhanced geothermal systems (EGS) and carbon capture utilization and storage (CCUS).  Encapsulation of solid nanomaterials within an oil-in-water (O/W) emulsion (i.e., Pickering emulsion) has been employed to prevent the aggregation and deposition of the nanomaterials in subsurface reservoirs in recent decades. Here, the dispersed phase droplets were decreased to nanoscale through a utilizable procedure. These nanodroplets were stabilized solely by polymer-coated magnetic iron oxide nanoparticles. Low-field NMR and X-ray CT were employed to constantly monitor the stability of Pickering nanoemulsions until phase separation. The polydisperse nanoemulsions are more easily separated due to the severely inhomogeneous chemical potentials of the emulsion droplets. Experimental and theoretical modeling results reveal that the Ostwald ripening is the main instability mechanism for nanoemulsions due to the very small droplets associated with a high surface area. The insolubility of long-chain hydrocarbons in water acts as a kinetic barrier to Ostwald ripening, making those nanoemulsions, both the Pickering and Classical (which is formed only by polymer) ones, inherently stable to Ostwald ripening.

The transport and retention of the Pickering nanodroplets in porous media is examined by X-ray CT imaging. Accordingly, in-situ transport of the nanoemulsions in a water-saturated sandpack was quantified spatiotemporally through X-ray CT. Effluents were collected and analyzed to further comprehend the nanoemulsion displacement and retention in porous media. Experimental results demonstrate that accumulation and retention of the nanodroplets in porous media are stimulated by ionic strength, nanodroplet size distribution, and nanoparticle wettability. Three transport modes in porous media (flow through with minimal retention, migration of accumulated nanodroplets, and retention of accumulated nanodroplets) can be achieved through carefully designing the nanoemulsion system.

These findings shed light on the fundamental understanding of the (nano-)colloidal dispersions transport in porous media and provide implications for IOR, EGS, and CCUS.

How to cite: Ding, B., Ahmadi, S. H., Bryant, S., and Kantzas, A.: Spatio-Temporal Imaging of Instability and Transport of Pickering Nanodroplets in Porous Media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3734, https://doi.org/10.5194/egusphere-egu24-3734, 2024.

The study of caprock assumes paramount significance, particularly in elucidating alterations in the sealing conditions of petroleum reservoirs. However, it is imperative that corresponding simulation experiments transcend a singular focus on CO2 and caprock, extending to a comprehensive study of the reservoir-caprock system. Experimental protocols were implemented, entailing the sequential flow of CO2-rich fluid first through the reservoir and subsequently through the caprock. The chosen samples and conditions were drawn from potential CO2 utilization and storage blocks in the Subei Basin, China, featuring sandstone reservoirs and mudstone caprocks. The experimental paradigm simulated the interaction when CO2 migrating along the sandstone and then reaching the mudstone caprock, spanning a duration of 37 days.

Results underscore that the introduction of CO2-rich fluid predominantly instigates the dissolution of sandstone reservoirs, with notable dissolutions observed in feldspar and clay minerals, while secondary mineral precipitation remains negligible. Upon the fluids traversal through the mudstone caprock, initial dissolution occurs in carbonate minerals, accompanied by continuous precipitation of secondary clay minerals. These secondary minerals not only occupy calcite dissolution pores but also precipitate on the surfaces of rock particles, asserting dominance in the water-rock reaction within the mudstone.

Supported by geological observations and numerical simulations, these experiments illuminate the material adjustment processes ensuing from the introduction of CO2-rich fluid into the reservoir-caprock system. The infusion of CO2-rich fluid induces mineral dissolution, augmenting pore space within the reservoir, with ion products subsequently transported to the mudstone caprock. Under conditions characterized by a slower flow rate and a more extensive water-rock reaction surface area in the mudstone caprock, the water-rock interaction accelerates the dissolution and reprecipitation of calcite and other minerals. The reprecipitated minerals effectively occupy caprock pores and fractures, thereby enhancing the caprock's sealing capacity.

How to cite: Zhou, B., Lun, Z., and Wang, B.: An Experimental Study of CO2 Flooding the Reservoir-caprock System: Implication for the Stability of Caprock during CO2 Intrusion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4095, https://doi.org/10.5194/egusphere-egu24-4095, 2024.

Linking the pore structure distributions and velocity-pressure relationship is important for understanding geological processes and in situ stress conditions. During the pressure loading, the pressure-velocity relationship is controlled by variation of pore-aspect-ratio spectrum distribution (pore-aspect-ratio vs. porosity) with pressure: on the one hand, the “flat crack” (aspect ratio) will be squeezed and closed, causing the large velocity variation in the low-pressure regimes; on the other hand, the shape and volume of the “round pore” (aspect ratio) are less sensitive to pressure, controlling the smaller velocity change at high pressures. The above pore-structure variation process and its effect on the velocity-pressure relationship allow us to invert and analyze the distribution characteristics from the laboratory velocity-pressure data.  

The power-law distribution has been universally applied to characterize the length and aperture distribution in natural fractures; however, it is still not well understood whether the pore-aspect-ratio spectrum distribution also follows the power law and how this power-law distribution relates to other power-law distributions of fractures. In this study, we examine the universality of the power-law relationship for the pore aspect ratio spectrum distribution and show that this distribution is the natural outcome of the power-law behavior of the length and aperture distribution in the rock fracture network.

We first collected laboratory ultrasonic velocity-pressure data for 52 rock samples with various porosities and lithologies. We then used a power law assumption to link the pore aspect ratio and porosity. The power-law exponents (hereafter referred to as the E factor) of the power-law distributions were successfully obtained by inverting the compiled velocity-pressure datasets. The inversion results showed a universal relationship between the E factor and porosity. We also demonstrated that the power-law distribution of the pore-aspect-ratio spectrum and the universal E factor-porosity trend can be explained using the length and aperture distribution characteristics of the microcrack system of rocks. This universal E factor-porosity trend provides a link between porosity and sensitivity of seismic velocities to pressure. Hence, our work not only emphasizes the relevance of natural fracture fractal distributions for a broad range of lithologies but also provides the parameterized method for relating the velocity-pressure relationship of any rock to porosity variation.

How to cite: Wang, H.-M., Tang, X.-M., and Doan, M.-L.: The power-law distribution of the rock pore structure: inversion and analysis of laboratory velocity-pressure data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4456, https://doi.org/10.5194/egusphere-egu24-4456, 2024.

EGU24-5512 | ECS | Posters on site | EMRP1.2

Prediction of Subsurface Physical Properties Through Machine Learning: The case of the Riotinto Mine. 

Abraham Balaguera, Pilar Sánchez-Pastor, Sen Du, Montserrat Torné, Martin Schimmel, José Fernández, Jordi Díaz, Jaume Vergés, Ramon Carbonell, Susana Rodríguez, and Diego Davoise

Recently, under the umbrella of a public-private collaboration project (CPP2021-009072), Atalaya Riotinto Minera S-L. and the CSIC through its institutes IGEO-Madrid and Geo3BCN-Barcelona, have undertaken an ambitious and innovative initiative to validate the applicability of state-of-the-art monitoring and prospecting systems for better tracking of deformations that may occur in the mine’s environment and to study the petrophysical properties and 3D structure of the mine subsurface. In this work, we present the results of machine learning (ML) models developed to predict various physical properties of rock (PPR) for classifying main lithologies. This analysis is based on over a thousand surface rock samples and nine wells with lithology descriptions and density logs. These data sets have allowed us to characterize the main geological units and formations comprising the subsurface of the Riotinto (RT) mine. A quality control process was applied to the PPR database through lithology and intervals to identify and correct outlier values. Multi-Layer Perceptron neural networks were employed to predict these outliers. Various mathematical and supervised machine learning models were developed to understand and predict PPR associated with different geological units. The models were compared to identify the most efficient and stable one. Additionally, new machine learning models were implemented to predict lithofacies based on PPR. These models were then used to predict PPR and classify lithofacies in wells within a mining site.

The results suggest that machine learning-based PPR prediction reduces uncertainty, providing a clearer understanding of the anisotropic characteristics of geological units. Apparent density, total porosity, and P-wave velocity properties were found to predict lithofacies with an accuracy of approximately 80%. In conclusion, this advancement not only redefines the precision with which lithofacies can be identified in the Riotinto mine but also establishes a new methodology for the lithological characterization of the subsurface, leveraging both well logs and direct measurements on surface samples. This study demonstrates the potential of using new ML techniques in mining and geology, as well as opening the door to the use of these models for 3D characterization of lithological units by integrating geophysical data at the exploratory level.

This work, financed with reference CPP2021 009072, has been funded by MCIN/AEI/10.13039/501100011033 (Ministry of Science, Innovation and Universities/State Innovation Agency) with funds from the European Union Next Generation/PRTR (Recovery, Transformation, and Resilience Plan).

Keywords: Machine Learning, Mining, Petrophysical Properties and Geological Characterization.

How to cite: Balaguera, A., Sánchez-Pastor, P., Du, S., Torné, M., Schimmel, M., Fernández, J., Díaz, J., Vergés, J., Carbonell, R., Rodríguez, S., and Davoise, D.: Prediction of Subsurface Physical Properties Through Machine Learning: The case of the Riotinto Mine., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5512, https://doi.org/10.5194/egusphere-egu24-5512, 2024.

EGU24-5612 | ECS | Posters on site | EMRP1.2

Pressure dependence of permeability in cracked rocks: experimental evidence of non-linear pore-pressure gradients from local measurements 

gang lin, Samuel Chapman, Dmitry Garagash, Jérôme Fortin, and Alexandre Schubnel

Understanding the coupling between rock permeability, pore-pressure and fluid-flow is crucial, as fluids play an important role in the Earth’s crustal dynamics. Here, we measured the distribution of fluid pressure during fluid-flow experiments on two typical crustal lithologies, a granite and a basalt. Our results demonstrate that the pore-pressure distribution transitions from a linear to a non-linear profile as the imposed pore-pressure gradient is increased (from 2.5 MPa to 60 MPa) across the specimen. This non-linearity results from the effective pressure dependence of permeability, for which two analytical formulations were considered: an empirical exponential or a modified power-law. In both cases, the non-linearity of pore pressure distribution is well predicted. However, using a compilation of permeability vs. effective pressure data for granitic and basaltic rocks, we show that our power-law model, based on crack micromechanics (combining Hertzian contact and cubic law theories), outperforms the exponential formulation at low effective pressures. 

How to cite: lin, G., Chapman, S., Garagash, D., Fortin, J., and Schubnel, A.: Pressure dependence of permeability in cracked rocks: experimental evidence of non-linear pore-pressure gradients from local measurements, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5612, https://doi.org/10.5194/egusphere-egu24-5612, 2024.

EGU24-6120 | ECS | Posters on site | EMRP1.2

Access for free: How to get free-of-charge access to Dutch Earth scientific research labs through EPOS-NL  

Richard Wessels and Ronald Pijnenburg

Access to top research equipment facilitates top research. However, the research equipment needed may not always be available within individual institutes, while access to external facilities may not in all cases be affordable, or even possible. This restricts the research that any individual can do and hampers scientific breakthroughs, particularly across disciplines. To overcome this limitation, a collaborative infrastructure network was initiated: EPOS-NL (European Plate Observing System- Netherlands). EPOS-NL provides free-of-charge access to geophysical labs at Utrecht University, Delft University of Technology, and the Dutch geological survey of TNO, all in the Netherlands, for research within rock physics, analogue modelling of tectonic processes, X-ray tomography and microscopy. These labs include capabilities for among others: A) Mechanical and transport testing at crustal stress, temperature and chemistry conditions; B) Large-scale experiments, e.g. up to 30 m-scale fluid transport testing and particle tracking, or hydrostatic compression (< 100 MPa) of 6m long samples; C) Analogue tectonic modelling, including dynamic model imaging in 2D and 3D; D) X-ray tomography at sub-µm resolution; E) A correlative workflow for electron microscopy and microchemical mapping, down to nm resolution; and F) Microfluidics: Direct visualization of dynamic, physical and chemical fluid transport processes in the pore networks. As such, these labs can provide you with the means and expertise for your research into the fundamental processes governing the behavior of the Earth’s crust and upper mantle.

Access to EPOS-NL can be requested by applying to a bi-annual call, posted on www.EPOS-NL.nl. This involves submitting a short (1-2 page) research proposal. Research proposals are reviewed on the basis of feasibility and excellence, but generally have a high chance of success (~80% in previous rounds). Interested? Have a look on the EPOS-NL website – and apply!

How to cite: Wessels, R. and Pijnenburg, R.: Access for free: How to get free-of-charge access to Dutch Earth scientific research labs through EPOS-NL , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6120, https://doi.org/10.5194/egusphere-egu24-6120, 2024.

EGU24-7192 | Orals | EMRP1.2

Time-lapse Acousto-Mechanical Response to Moisture-Induced Reduction of Fracture Stiffness in Granite 

Rui Wu, Paul Selvadurai, Ying Li, Kerry Leith, Qinghua Lei, and Simon Loew

Water infiltration into crustal rocks, particularly through fractures, significantly impacts seismic wave propagation and the characterization of fracture systems. Our study (Wu et al, 2023a) investigates the acousto-mechanical behavior of fractured granite experiencing gradual water infiltration over 12 days. We reveal an order of magnitude difference in wave amplitudes when compared to intact granite, with a correlation between wave amplitudes and the movement of the wetting front. The laboratory experiments show that fracture stiffness decreases exponentially as the wetting front advances, indicating moisture-induced matrix expansion (Wu et al, 2023b) around the fracture leads to increased asperity mismatch and reduced stiffness. By back-calculating the fracture stiffness and capturing the effects of water infiltration on seismic attenuation through a numerical model, this research illuminates how elastic waves propagate across fractures undergoing moisture-induced expansion, a crucial aspect of fracture characterization and understanding of the near-surface environment's response to hydrological changes. Our research sheds light on an important question in fracture characterization: how elastic waves propagate across a fracture undergoing moisture-induced expansion.

Publications related to this research:

Wu, R., Selvadurai, P. A., Li, Y., Leith, K., Lei, Q., & Loew, S. (2023a). Laboratory acousto-mechanical study into moisture-induced reduction of fracture stiffness in granite. Geophysical Research Letters, 50, e2023GL105725. https://doi.org/10.1029/2023GL105725

Wu, R., Selvadurai, P. A., Li, Y., Sun, Y., Leith, K., & Loew, S. (2023b). Laboratory acousto-mechanical study into moisture-induced changes of elastic properties in intact granite. International Journal of Rock Mechanics and Mining Sciences, 170, 105511. https://doi.org/10.1016/j.ijrmms.2023.105511

How to cite: Wu, R., Selvadurai, P., Li, Y., Leith, K., Lei, Q., and Loew, S.: Time-lapse Acousto-Mechanical Response to Moisture-Induced Reduction of Fracture Stiffness in Granite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7192, https://doi.org/10.5194/egusphere-egu24-7192, 2024.

EGU24-7768 | Posters on site | EMRP1.2

Fast quantitative estimation method of fracture cavity porosity based on convolution deep neural network 

Zhean Zhang, Longcheng Liu, Qingyin Xia, Tingting Xie, and Yuqing Niu

       Traditional interpretation of imaging logging data often involves manually importing various data types to calculate the porosity of fractures in the target area. This process becomes challenging due to the lack of gas and oil information in the raw data, especially when dealing with less-than-ideal raw data. The proposed method addresses this challenge by offering a rapid estimation approach for fracture porosity that reduces manual work and enhances process efficiency within an acceptable error limit.  

       The estimation method relies on path morphology [1] and convolutional neural networks for the extraction of fracture and cavity parameters. Initially, a path morphology method is applied to identify inclined fractures, followed by the use of a rotation jamming algorithm [2] to obtain rectangles with the minimum area in each cavity. These rectangles incorporate the angle of the rectangle and the lengths of its short and long sides. Parameters related to horizontal fractures, vertical fractures, and cavities are then utilized for the estimation of porosity.

      The original imaging logging conductivity is processed to distinguish inclined fractures from other fractures during the extraction process. Traditional binarization and denoising methods are not directly applied since cavities on basic binary images are also white. Thus, specific curves need to be extracted from the original conductivity images using a path morphology algorithm. On the other hand, convolutional neural networks (CNNs) are required for the identification of the shape of restored cracks due to the influence of cavities on traditional mathematical fitting processes. LeNet and AlexNet, among various CNN algorithms, are employed for this purpose. Specifically, the modified AlexNet algorithm adopts the maximum pooling method, Softmax function in the output layer, and the Adam optimizer in the learning process to improve efficiency and reduce memory occupation. The related parameters of cavities, horizontal fractures, and vertical fractures are calculated by the rotation jamming algorithm after the extraction of inclined fractures. Traditional Hough transform is considered time-consuming for evaluating a large number of cavities, leading to the adoption of an alternative approach—obtaining circumscribed rectangles with minimum area in a connected domain. This approach improves computation speed by focusing on directions coinciding with the long side of polygons, treating the long and short sides of rectangles as the major and minor axes of ellipses. In a conductivity image, cavities contain both convex and concave closures simultaneously, requiring the filling of concave ones to convex before applying the rotation jamming algorithm. The effective porosity parameters can be obtained using the developed programs.

      The method offers high efficiency and automation, extracting various types of fractures along with cavities within an acceptable error limit, providing valuable information for geologists in evaluating high-potential targets.

[1]Li et al. Estimating Porosity Spectrum of Fracture and Karst Cave from Conductivity Image by Morphological Filtering. JJU, 2017, 47(04): 1295-1307.

[2] Toussaint, G.T. A simple linear algorithm for intersecting convex polygons. The Visual Computer 1, 1985: 118–123. 

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How to cite: Zhang, Z., Liu, L., Xia, Q., Xie, T., and Niu, Y.: Fast quantitative estimation method of fracture cavity porosity based on convolution deep neural network, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7768, https://doi.org/10.5194/egusphere-egu24-7768, 2024.

EGU24-8600 | Orals | EMRP1.2

Response of the caprock's fluorescence parameters to the leakage of palaeo-oil zones 

Keshun Liu, Jiangxiu Qu, Ming Zha, and Xiujian Ding

Abstract: The northern part of the the Junggar Basin is the Siberian plate, and the western part is the Kazakhstan plate, which is an important part of the Central Asian orogenic belt. This study discusses how fluorescence parameters inside the mudstone caprocks of the Mobei Bugle and Mosuowan Bugle respond to the leakage of palaeo-oil zones. It is based on X-ray diffraction analysis, TOC testing, physical property testing, rock pyrolysis experiments, and image observation. First, using quantitative fluorescence technology, it was established that the appropriate particle size range for the study area mudstone is between 100 and 140 mesh by examining the QGF E intensity and sample loss rate of the control group. Then, the influence of retained primary hydrocarbons inside the mudstone on the test results of quantitative fluorescence technology is speculated to be relatively weak based on an analysis of the correlation between TOC value and total hydrocarbon value, TOC value and fluorescence parameters. The QGF index of the 5265-5302m reservoir in PD1 well ranges from 3.9 to 87.2, with an average of 16.18; the QGF index of the 7034-7195m reservoir in MS1 well ranges from 2.2 to 57.5, with an average of 11.6. The reservoirs of the PD1 and MS1 wells contain palaeo-oil zones, based on the QGF index classification criteria. Both image observation and micro resistivity imaging logging analysis demonstrate that the caprock's physical properties in the PD1 well are inferior to those in the MS1 well. The pore types of the PD1 well caprock are filled dissolution pores and residual intergranular pores, whereas the pore types of the MS1 well caprock are dissolution pores and microcracks. There is a discrepancy of approximately 9 times between the development density of fractures in the MS1 well caprock (0.989 pieces/m) and the PD1 well caprock (0.114 pieces/m). The palaeo-oil zone can be effectively sealed due to the poor physical properties of the PD1 well caprock. The oil testing conclusion of the reservoir is oil-water layer, with a daily oil production of 8.52t. Therefore, as the depth decreases, the QGF E intensity value decreases, and the QGF λmax and TSF R1 values reflect higher hydrocarbon maturity. The MS1 well caprock has good physical properties and cannot effectively seal the palaeo-oil zone. The oil testing conclusion of the reservoir is water layer, with a daily oil production of 4.4t. As the depth decreases, the QGF E intensity value increases, and the QGF λmax and TSF R1 values reflect lower hydrocarbon maturity. Comprehensive analysis suggests that the fluorescence parameters inside the caprock exhibit characteristics related to the degree and form of palaeo-oil zone leakage.

Keywords: Quantitative fluorescence technology, Fluorescence parameters, Mudstone caprock, Palaeo-oil zones

How to cite: Liu, K., Qu, J., Zha, M., and Ding, X.: Response of the caprock's fluorescence parameters to the leakage of palaeo-oil zones, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8600, https://doi.org/10.5194/egusphere-egu24-8600, 2024.

EGU24-8632 | Posters on site | EMRP1.2

Seismic properties of serpentinites under increasing pressure and temperature conditions 

Mai-Linh Doan, Heming Wang, Anne-Line Auzende, Stéphane Schwartz, Samuel Chapman, and Jérôme Fortin

Serpentinites result from the hydration of ultramafic rocks (e.g., peridotite and pyroxenite) that transform primary mineralogical assemblages (olivine-pyroxene) into different serpentine species (lizardite-chrysotile-antigorite) depending on the pressure-temperature (P-T) conditions (Schwartz et al, 2013) related to geodynamic context. Serpentinization mainly occurs from oceanic ridges at LP conditions to subduction zones at HP conditions and its extent needs to be quantified.

The Vp/Vs ratio is a tool of choice to distinguish serpentinite from other mafic to ultramafic rocks and thus to investigate the serpentinization extent. The seismic velocity of serpentinites depends on the type and the volume of serpentine species (lizardite/antigorite) present in the rock, as well as the microstructural evolution of the serpentinite, however, these topics remain poorly understood.

We selected blueschist and eclogitic serpentinite samples collected in the internal zone of the western Alps. One eclogitic serpentinite sample was also experimentally dehydrated at 700°C in standard pressure conditions. The petrology and (micro)structures of the samples were characterized using both 2D petrological thin sections and 3D X-ray tomography. We performed velocity measurements on the samples at low frequencies (quasi-static stress-strain method: 0.02-1000 Hz) and ultrasonic frequency (wave travel time method: MHz) at different effective pressures (low-frequency experiments: 2-25 MPa; ultrasonic experiments: 0-70 MPa). The description of experimental equipment and methodology can be found in Borgomano et al. (2020). The studied frequency range covers the field geophysical data frequency band and therefore provides better constraints for interpreting the serpentinization extent. As expected, the Vp/Vs ratio changes depending on the mineralogy: lizardite is characterized by higher Vp/Vs (2-2.1) and lower Vp (5200-5700 m/s) than antigorite with lower Vp/Vs (1.75-2) and higher Vp (6000-7000 m/s). Anisotropic structure due to mineral preferred orientation manifest by velocity variation with sample orientation: overall, the Vp and Vs anisotropy degree (Ap, As) of antigorite (Ap:3%-18%; As:1%-16%) are larger than those of lizardite (Ap:3%-9%; As:3%-8%). Furthermore, the seismic velocity of the serpentinite is almost unchanged with pressure and frequency, but pressure- and frequency-dependence of the velocity arise in the dehydrated antigorite sample: 1) in dry condition, with lower Vp/Vs ratio (1.46-1.6) and lower Vp (3500-4600 m/s) in the effective pressure range of 2-25 MPa and almost no frequency dispersion; 2) in water-saturated condition, with higher Vp/Vs ratio (1.87-1.89) and higher Vp (5060-5190 m/s) at ultrasonic frequency, as well as a significant velocity dispersion band linking the results from seismic frequencies to ultrasonic frequency. This study contributes to the calibration of seismic velocity profiles to track the mineralogical transition between lizardite and antigorite, which is related to increasing degrees of metamorphism.

 

References:

Schwartz et al. (2013). Pressure–temperature estimates of the lizardite/antigorite transition in high pressure serpentinites. Lithos, 178, 197-210.

Borgomano et al. (2020) An apparatus to measure elastic dispersion and attenuation using hydrostatic-and axial-stress oscillations under undrained conditions. Rev. Sci. Instrument, 91(3).

How to cite: Doan, M.-L., Wang, H., Auzende, A.-L., Schwartz, S., Chapman, S., and Fortin, J.: Seismic properties of serpentinites under increasing pressure and temperature conditions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8632, https://doi.org/10.5194/egusphere-egu24-8632, 2024.

EGU24-9014 | Orals | EMRP1.2

Influence of microplastic occurrence on complex conductivity of river sediments 

Shuai Li, Mingsa Xu, Yumeng Peng, and Xiangyun Hu

This study utilized an improved sand column experimental setup to investigate the effects of microplastic on Yangtze River bank sediments. The experiments conducted included Darcy experiments, electrokinetic experiments, and wettability experiments, together for the same sample. By varying the particle size of the microplastics in the samples, we were able to observe different response of the electrical properties as well as hydrogeophysical parameters in the samples.

Results show that increasing the mass fraction of mixed microplastics generally resulted in a significant decrease in sample electrical conductivity associated with an increase in permeability. These were expected to be due to the weak conductivity and strong hydrophobic properties of plastic particles, as well as the small adhesive forces between particles, which increased the pore space of the sediments and ultimately increased permeability. However, an anomalous increase trend was observed when decreasing the particle size of the mixed microplastics. Under this condition, increasing the concentration of same size plastic particles enhanced the electrical conductivity of the sediment sample. This anomaly phenomenon was reflected in both permeability and wettability, resulting in a decrease in sample permeability and a significant increase in sample hydrophobicity. Our observations using optical microscopy revealed two types of microplastic distribution in the sediments: one case was that microplastic particles were distributed within sediment pores and they did not touch each other, the other was that they were adsorbed onto sediment particle surfaces. We hypothesized that changes in the existence form of microplastics altered the double-layer structure of sediments, ultimately changing their hydrogeophysical parameters. This work has significance and relevance for electromagnetic-based characterization of microplastic-filled porous materials; for example, estimation of microplastic abundance in sediments.

How to cite: Li, S., Xu, M., Peng, Y., and Hu, X.: Influence of microplastic occurrence on complex conductivity of river sediments, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9014, https://doi.org/10.5194/egusphere-egu24-9014, 2024.

EGU24-9568 | ECS | Orals | EMRP1.2

Reducing boundary effects during True Triaxial loading of rocks 

Ashley Stanton-Yonge, Thomas Mitchell, Philip Meredith, John Browning, and David Healy

Even though stresses in the crust are triaxial (𝜎1>𝜎2>𝜎3) the overwhelming majority of rock deformation experiments are conducted under axisymmetric (or conventional triaxial) loading (𝜎1>𝜎2=𝜎3). This configuration disregards the effect of 𝜎2 on the physical and deformation properties of rocks, thus complicating and degrading the extrapolation of results to natural crustal conditions. A True Triaxial loading configuration is necessary to overcome this simplification, however, these improvements in addressing real crustal conditions come at a cost, which is the challenging boundary conditions that arise from having six loading rams rather than just two. Two main loading boundary effects can severely impact the stress distribution and failure mechanism of samples deformed in a True Triaxial Apparatus (TTA): 1) the end friction effect caused by the stiffness contrast between the rock sample and the metal loading platens, and 2) the unstressed sample edges resulting from the requirement that loading platens must necessarily be slightly smaller than the rock specimen. Managing and reducing these boundary effects is fundamental for obtaining accurate and representative data from true triaxial experiments, and for the further development of these apparatuses.

A novel TTA developed in the UCL Rock & Ice Physics Laboratory was designed to subject cubic or cuboid rock samples to truly triaxial stresses through the independent control of six loading rams. The apparatus is equipped with a confining and pore pressure system that allows for the deformation of saturated samples whilst simultaneously measuring permeability along the three axes. A suite of Finite Element Method (FEM) models was implemented to evaluate the parameters that minimize loading boundary effects in UCL’s TTA for a 50 mm edge-length cubic sample of sandstone. Our results indicate that using aluminum loading platens (𝐸𝑠𝑎𝑚𝑝𝑙𝑒/𝐸𝑝𝑙𝑎𝑡𝑒𝑛=0.47) reduces the end friction effect by a factor of two compared to using steel platens (𝐸𝑠𝑎𝑚𝑝𝑙𝑒/𝐸𝑝𝑙𝑎𝑡𝑒𝑛=0.17). In addition, we find that elevated confining pressure significantly reduces the stress concentration produced by unstressed edges. Specifically, a confining pressure of 10 MPa eliminates tensile stresses at the sample corners. These results are currently being implemented into the experimental protocol and execution in UCL’s TTA in order to ensure that we obtain reliable true triaxial data. However, these observations are generic and could therefore contribute to improved development and operation of true triaxial loading systems generally.

How to cite: Stanton-Yonge, A., Mitchell, T., Meredith, P., Browning, J., and Healy, D.: Reducing boundary effects during True Triaxial loading of rocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9568, https://doi.org/10.5194/egusphere-egu24-9568, 2024.

EGU24-9712 | ECS | Orals | EMRP1.2

Modeling of spectral induced-polarization measurements on cm-sized metallic spheres in sand-water-mixtures 

Dennis Kreith, Katrin Breede, Zeyu Zhang, Andreas Weller, and Matthias Bücker

The detection of metallic particles in the subsurface has been an important field in applied geophysics for several decades, e.g. in the exploration of ore deposits or in monitoring measurements at bioremediation sites. Due to the comparably high conductivity and high polarizability of metallic particles, geophysical methods using the electrical conductivity and especially induced polarization are highly suitable methods for applications of this kind.

To correctly interpret data measured in the field, a deep understanding of the underlying conduction and polarization mechanisms is necessary. Both, laboratory measurements with controlled experimental conditions and theoretical models describing the basic physical processes can help to achieve this kind of understanding. However, theoretical models usually are not suitable to be directly compared to laboratory measurements, because they usually consider idealized situations and exhibit a large number of free parameters that can not be controlled in measurements.

To overcome this gap, we compare experimental data of a cm-sized metallic sphere embedded in water-saturated sand with a corresponding theoretical model. To explain the remaining differences between measured and modeled data, we discuss how different processes, e.g. the geometry of the measurement setup or dissolved metal ions in the fluid, might affect the measurement and adapt our model accordingly. By doing so, we are able to reproduce the experimental results with the predictions by our theoretical model.

How to cite: Kreith, D., Breede, K., Zhang, Z., Weller, A., and Bücker, M.: Modeling of spectral induced-polarization measurements on cm-sized metallic spheres in sand-water-mixtures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9712, https://doi.org/10.5194/egusphere-egu24-9712, 2024.

EGU24-11028 | ECS | Posters on site | EMRP1.2

Experimental Analysis and Creep-Fatigue Damage Modeling of Sandstone Deformation related to Energy Storage Systems 

Deyan Tian, Zhengyang Song, Kavan Khaledi, Zhen Yang, and Florian Amann

The porous sandstone formations offer large capacities for the geological storage of clean energy sources like hydrogen and compressed air. This paper aims to investigate the deformation mechanisms in sandstone under the varying loading conditions. Employing a combined experimental and numerical approach, we investigate the mechanical behavior of sandstone under cyclic loading conditions. The results obtained in this study indicate three distinct deformation regimes in sandstone specimens developed under multi-level, multi-frequency cyclic loads, i.e.,1) instantaneous elastic deformation, 2) transient and steady-state strain due to creep, and 3) rapid deformation leading to fatigue failure, mainly driven by micro-crack development. In response to these deformation mechanisms, a viscoelastic-damage model is proposed. This model is based on the standard Burger's viscoelasticity combined with an energy-driven damage model to represent the creep-fatigue behavior in sandstone. The modeling results were verified by comparing the predictions with the experimental data. The experimental and numerical results presented an essential insight for designing and managing geological storage systems in sandstone formations.

How to cite: Tian, D., Song, Z., Khaledi, K., Yang, Z., and Amann, F.: Experimental Analysis and Creep-Fatigue Damage Modeling of Sandstone Deformation related to Energy Storage Systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11028, https://doi.org/10.5194/egusphere-egu24-11028, 2024.

EGU24-11658 | ECS | Orals | EMRP1.2

Characterizing Rock Physical Properties in the Nevados de Chillán Geothermal System 

Valentina Mura, Gloria Arancibia, John Browning, David Healy, Julian Mecklenburgh, and Diego Morata

In geothermal systems the thermo-physical properties of the rocks change as they interact with fluids passing through the volcanic system and during discrete events such as earthquakes and magma intrusion. To characterize a geothermal system and the flow of fluid through a sub-volcanic complex, targeted rock physical tests are needed for the rocks of the area conducted at natural P-T conditions. Here, we present rock property characterization of the main geological units of the active Nevados de Chillan Geothermal System, located in the Southern Volcanic Zone (SVZ), an area with some of the largest geothermal potential in the Andes. 

Six representative blocks of the geothermal host reservoir and overlying strata were collected from the volcanic basement. The main geomechanical units of this system are (from oldest to youngest): 1) andesites, tuffs and breccia of the Cura-Mallin Formation (Miocene country rocks); 2) granodiorites and diorites of the Santa Gertrudis Bullileo Batholith (15.7 Ma and 5.9 Ma, respectively); and 3) hornfels from the contact between the granitoids and country rocks. Cylindrical core samples (26 mm diameter x 65 mm length) from each block were used to quantify density, porosity, and ultrasonic wave velocities at different confining pressures. All tests were carried out at the Rock Deformation Laboratory, University of Manchester. Polished thin sections were prepared from blocks of the same orientation as the cored directions and analyzed using petrographic.

Granodiorite has the lowest porosity at between <1 to 2% and the fastest P- and S-wave velocities (5.5 to 5.9 km/s and 3.1 to 3.5 km/s, respectively). The diorite has a higher porosity of between 4 to 6% which coincides with lower ultrasonic velocities (3.5 to 5.0 km/s and 3.5 to 5.0 km/s, respectively). This can be explained by the higher presence of macro, micro-fractures, and alteration minerals in the diorite. Hornfels has possess similar porosities (>2%) to the granodiorite and 4.8 to 5.7 km/s P-wave velocities and 2.7 to 3.3 km/s S-wave velocities. The andesitic lavas have porosities ranging 3-7%, while the tuffs and breccias have porosities of 12-30%. Elastic waves velocities in the andesitic lavas are around 2 km/s faster than the pyroclastic rocks.

Tests with cycles of increasing and decreasing hydrostatic pressure (up to approximately 150 MPa) show that granodiorite and diorite exhibit sharp increases in P-wave velocity (Vp). This is attributable to the stiffening of the rock from the progressive closure of pre-existing cracks. Above 40 MPa, the rate of increase in Vp with pressure reduces markedly, implying that the remaining porosity is less compliant. This is consistent with the maximum burial depth of the rocks suggesting that those cracks formed because of bringing the rocks to the surface.

Finally, in terms of microstructural observations, the granodiorites, diorites and hornfels have large intragranular and intergranular fractures with very high aspect ratio, which are commonly oriented and therefore impart anisotropy. In contrast, the andesitic, tuffs and breccias porosity is higher than the crystalline rocks and is mainly composed of intergranular pores with low aspect ratios and relatively isotropic.

How to cite: Mura, V., Arancibia, G., Browning, J., Healy, D., Mecklenburgh, J., and Morata, D.: Characterizing Rock Physical Properties in the Nevados de Chillán Geothermal System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11658, https://doi.org/10.5194/egusphere-egu24-11658, 2024.

In petrophysics, characteristic lengths are used to relate fundamental transport properties of porous media. However, these characteristic lengths have mostly been defined and tested in fully saturated conditions, with few exceptions. This contribution revisits the seminal work of Johnson-Koplik-Schwartz (JKS) length, which represents an effective pore size controlling various transport-related properties of porous media, such as permeability and electrical conductivity. A novel closed-form equation is presented to predict the behavior of this characteristic length in partially saturated media for different saturation states. Using previous models in the literature that predict the intrinsic and relative electrical conductivities under partially saturated conditions, we infer the JKS length as functions of water saturation and properties associated with the pore-size distribution of the considered porous medium. The proposed method allows for the direct estimation of effective and relative permeability through electrical conductivity measurements. This creates new opportunities for remotely characterizing partially saturated media. We believe that this new model has potential for various applications in reservoir (CO2 or hydrogen storage) and vadose zone studies.

How to cite: Jougnot, D., Thanh, L. D., Solazzi, S., and Luo, H.: Revisiting the Johnson-Koplik-Schwartz characteristic length to relate transport properties in partially saturated porous media, insights from a fractal-based petrophysical approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12012, https://doi.org/10.5194/egusphere-egu24-12012, 2024.

EGU24-12229 | ECS | Posters on site | EMRP1.2

Nanostructures as an indicator for deformation dynamics  

Sarah Incel, Markus Ohl, Frans Aben, Oliver Plümper, and Nicolas Brantut

Grain-size reduction – with amorphization or melting as its extreme forms – plays a crucial role in fault-zones dynamics, e.g., the nucleation or arrest of earthquakes. Previous experiments have been mostly conducted on powdered samples and structural investigations of experimentally generated fault-gouge material provide contrasting results when it comes to the initiation of melting during fault slip. In the present study, we deformed four intact Westerly granite samples, to decipher whether there is a correlation between failure mode, i.e., controlled, self-stabilised, or dynamic, and grain-size reduction within the developing fault gouge. Controlled failure took place over several hours, self-stabilised failure occurred within a few seconds and dynamic failure lasted less than a second. To test the influence of aqueous fluids on the grain-size evolution within fault gouges, two runs were performed on samples, dynamically failing either in the presence or absence of pore fluids. All samples were deformed at the same effective pressure of 40 MPa and displacements along the newly created faults were with 1.2 to 2.0 mm in a similar range. We investigated the microstructures of each sample using a scanning electron microscope (SEM) and cut two focused-ion beam (FIB) sections per sample from selected areas, located within the fault gouges, to analyse their nanostructures using a transmission electron microscope (TEM). At low magnification at the SEM, no striking differences between the different fault gouges are visible. Features resembling “cooling cracks” become apparent at the highest magnification at the SEM and are only found in the samples that failed dynamically. Major differences between the samples are only obvious when comparing their nanostructures using TEM imaging. In the high-resolution TEM images as well as with the aid of selected area electron diffraction (SAED), we observe a clear correlation between failure mode or rupture speed and grain-size reduction, with an increase in amorphous material as rupture speed increases. Regardless of the availability of fluids, the samples that underwent dynamic failure reveal similar nanostructures. Both exhibit flow structures created by amorphous material. We believe that latter is the result of melting as we find numerous structural and chemical evidence for melting, e.g., euhedral magnetite crystals of a few tens of nanometer with adjacent depletion halos. Such indicators for melting are absent in samples that failed in a controlled or self-stabilised manner, highlighting the importance of rupture speed on fault gouge melting.

How to cite: Incel, S., Ohl, M., Aben, F., Plümper, O., and Brantut, N.: Nanostructures as an indicator for deformation dynamics , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12229, https://doi.org/10.5194/egusphere-egu24-12229, 2024.

EGU24-12400 | ECS | Orals | EMRP1.2

Behavior of elastic properties in carbonates: scale does matter 

Cédric Bailly, Emmanuel Léger, Simon Andrieu, Jean-Baptiste Regnet, Mathis Bergogne, Gaël Monvoisin, Bertrand Saint-Bezar, Perrine Mas, Hermann Zeyen, and Benjamin Brigaud

Understanding the evolution of rock physical properties with changing scale is a critical challenge when characterising spatial subsurface heterogeneities. One of the possible approaches can be using elastic wave velocities at various scales, from laboratory to field, by solely tuning the sensing wavelength to the studied media. Theoretically, in the case of a dry, isotropic, and homogeneous porous medium, at all scales of investigation, the elastic properties are not dependent on the scales of analysis (non-dispersive medium). However, as already pointed out in the literature, carbonate rocks have very heterogeneous pore networks at different scales, which may lead to different Representative Elementary Volumes (REV) with changing scales. In our work, we assume that the elastic wavelength is equal to the upper bound of the REV.

In this study, we investigated marine carbonate rocks of Middle Jurassic age outcropping in the western part of France (Charentes, near Angouleme city) in four different quarries. A total of three REVs were investigated, always in dry conditions: i) the centimeter scale, acquiring P and S wave velocities (Vp, Vs) on 60 cylindrical samples of one inch-diameter using a central frequency of 500 kHz (wavelength ~ 1 cm); ii) the decimeter scale, acquiring more than 1500 measurements of Vp and Vs on outcropping carbonates with a frequency of 40 kHz (wavelength ~ 10 cm); and iii) the decameter scale acquiring seismic wave velocity measurements along a vertical profile (geophones connected to a vertical outcrop wall), where the 6 kg sledgehammer source was situated on the plateau, delivering a frequency of 100 Hz (wavelength ~ 10 m). In parallel, a thorough geological description was done at all the investigated scales, combining i) microscope-driven microstructure analysis of samples under the microscope, ii) sedimentary facies description of outcrops and iii) fracture orientation analysis on photogrammetric models of quarries.

The elastic wave velocity results were interpreted considering facies and diagenetic processes of sedimentary rock fabric. At the centimeter scale (i), for a given sedimentary facies, we show a clear control of diagenesis (cementation and dissolution) on the elastic properties, in agreement with the well-documented literature. At the decimeter scale (ii), horizontal and vertical Vp-Vs data were used to construct 2D acoustic property maps (1 square meter). Two extreme behaviors can be pointed out. On the one hand, velocity data are homogeneous and anisotropic in zones showing evidence of primary stratification and lithostatic compaction. On the other hand, data are heterogeneous and isotropic in zones exhibiting significant early diagenesis heterogeneities (“hardgrounds”). These results are thus linked to facies and diagenesis heterogeneities. Finally, at the decameter scale, seismic velocities clearly show an azimuthal anisotropy, mainly controlled by the occurrence of outcropping open joints from tectonic origin. Our study tends to highlight the crucial need to always characterise sedimentary facies, diagenesis evolution and structural overprint in carbonate reservoir rocks if one wants to interpret and correctly understand the multi-scale elastic properties of carbonates.

How to cite: Bailly, C., Léger, E., Andrieu, S., Regnet, J.-B., Bergogne, M., Monvoisin, G., Saint-Bezar, B., Mas, P., Zeyen, H., and Brigaud, B.: Behavior of elastic properties in carbonates: scale does matter, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12400, https://doi.org/10.5194/egusphere-egu24-12400, 2024.

EGU24-12452 | Orals | EMRP1.2

Reservoir compaction during and after fluid production: A case study of the Groningen Gas Field 

Suzanne Hangx, Ronald Pijnenburg, Takahiro Shinohara, Mark Jefferd, Mohammad Hadi Mehranpour, and Christopher Spiers

Prolonged hydrocarbon production often leads to subsidence and seismicity in offshore and onshore hydrocarbon fields. In the Netherlands, tens of centimetres of subsidence has occurred above the Groningen Gas Field, with widespread induced seismicity during the 60+ years of its lifetime. These phenomena are driven by reservoir compaction at depth, resulting from gas extraction. Modelling the reversible, elastic component of compaction is straightforward. However, permanent deformation can also occur, the rate and effects of which are very poorly constrained. Furthermore, from smaller fields in the vicinity, it has already become clear that compaction may continue even now that production has stopped in 2023. To be able to confidently forecast the long-term surface impact of fluid production, for fields such as Groningen, and many other fields around the world, models are required that include the physical mechanisms responsible for reservoir compaction. These mechanisms are still poorly known and quantified at true reservoir conditions. Combining microstructural observations, obtained from field material and experimental work, and novel experimental mechanical data, obtained at simulated stress changes relevant to the reservoir, enabled us to identify the main grain-scale deformation mechanisms operating in the reservoir sandstone of the Groningen Gas Field. A key role is played by the thin intragranular clay layers present between the quartz grains making up the load-bearing framework. Compaction of and slip along these thin clay films has accommodated the permanent deformation accumulated during the production stage. After production is halted, experiments suggest that slow, time-dependent grain breakage will start to play a role as well. Microphysical models describing rate-insensitive compaction were implemented in Discrete Element models to assess sandstone compaction behaviour at the cm-dm scale. These numerical models can be used to evaluate reservoir compaction in different locations on the field due to pressure equilibration or repressurisation, with rate-sensitive mechanisms, such as stress corrosion cracking, to be added at a later stage, as their descriptions are still be developed. Eventually such small-scale numerical models should form the basis to upscale the sandstone behaviour to the reservoir scale.

How to cite: Hangx, S., Pijnenburg, R., Shinohara, T., Jefferd, M., Mehranpour, M. H., and Spiers, C.: Reservoir compaction during and after fluid production: A case study of the Groningen Gas Field, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12452, https://doi.org/10.5194/egusphere-egu24-12452, 2024.

Carbon capture and storage (CCS) stands as a key technology for mitigating CO2 emissions, with depleted oil and gas fields being excellent candidates for geological storage. However, injection of relatively cold, high-pressure CO2 into higher temperature, low-pressure hydrocarbon reservoirs can induce cooling and potential freezing due to the temperature difference between the injected fluid and the reservoir, as well as Joule-Thomson cooling caused by the rapid expansion of the fluid upon entering the reservoir. This may impact wellbore integrity, and near-wellbore stability and injectivity, posing challenges for safe and cost-effective storage. To be able to accurately predict the impact of cooling on storage operations, it is important to quantify the impact of temperature cycling on the mechanical and transport properties of the rock formations in the near-wellbore area.

To address this, we performed thermal cycling experiments under realistic in-situ pressure-temperature conditions on sandstone analogous to typical hydrocarbon reservoir material. We used a novel apparatus comprising a hydrostatic pressure vessel placed inside a climate chamber providing a temperature range of -70°C to +180°C. Bleurswiller sandstone (Vosges, France; 24% porosity) was subjected to temperature changes from 100 °C to +40, +5, or -20°C at constant pore fluid pressure (5 MPa; 0.85 M NaCl brine) and confining pressure (10 or 25 MPa, i.e. similar to reservoirs of up to ~3 km depth). The effect of the rate of temperature change, brine saturation and the number of cycles on the volumetric behaviour of the sandstone were systematically investigated. Thermally treated samples were subsequently subjected to permeability measurements and conventional triaxial compression to evaluate the impact of confined temperature cycling on the transport and mechanical properties.

In all our thermal cycling experiments, we observed permanent volume change (compaction) with each cycle, though the amount of compaction decreased with subsequent cycles. Furthermore, our results showed that confined temperature cycling did not significantly alter the mechanical properties (strength, elastic properties) of Bleurswiller sandstone. This is in contrast to the strength reduction observed in other porous sandstones after unconfined thermal cycling. However, our thermally treated samples did exhibit a significant reduction in permeability by several orders of magnitude (κ = 10-15 to 10-16 m2 post-treatment) compared to untreated reference samples (initial κ = ~10-14 m2). Overall, permeability roughly decreased with increasing brine content (i.e. from dry to fully brine saturated), increasing number of thermal cycles, and increased temperature amplitude (i.e. more cooling). Temperature change rate did not affect the permanent volumetric strain or permeability reduction in samples that were only cooled. In experiments achieving sub-zero temperatures, including pore fluid freezing, slower temperature changes resulted in less permeability reduction.

How to cite: Amiri, S., Pijnenburg, R., and Hangx, S.: Effects of Temperature Cycling on the Mechanical and Transport Properties of Porous Sandstone: Implications for CO2 Storage in Depleted Hydrocarbon Reservoirs , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12566, https://doi.org/10.5194/egusphere-egu24-12566, 2024.

EGU24-13701 | Orals | EMRP1.2

Influence of Geochemical Features on Elastic and Fracture Behavior of Organic Matter 

Junliang Zhao, Pengyu Zhang, Wei Zhang, and Dongxiao Zhang

As the source material of hydrocarbon and a significant matrix constituent in organic-rich shale, organic matter influences not only the oil/gas generation and accumulation but also the mechanical behavior of shale formations. Previous researches have found that organic matter exhibits different mechanical properties from inorganic minerals, and proved that geochemical features could significantly affect the elastic behavior of organic matter in shale. Here, this work systematically investigates the influence of organic type and/or thermal maturation on mechanical behavior of organic matter. For elastic behavior, in conjunction with vitrinite reflection test, scanning electron microscope (SEM) observation, and micro-Raman analysis, nanoindentation is performed to measure the modulus of different macerals. The results indicate that with the same thermal maturity, inertinite has the highest Young’s modulus, while the modulus of bitumen is the lowest. In addition, with the increase of thermal maturity, the Young’s moduli of all kinds of maceral tend to increase, while the intensity ratio of D peak to G peak measured by micro-Raman analysis shows a decreasing trend, which indicates a higher degree of graphitization. For fracture behavior, maceral identification, focused xenon ion beam fabrication, and in situ fracture test are combined to analyze the deforming and fracturing process of different organic types. Micro cantilever beams are manufactured by using a xenon plasma focused ion beam-SEM (Xe PFIB-SEM), and then loaded in an environmental SEM (ESEM). Organic matter particle is set at the fixed end of cantilever beam, and the load is applied at the free end. Thus, the interaction between micro crack and organic matter can be observed and the corresponding mechanical data can be recorded. Test results indicate that the micro cantilever beams dominated by inertinite and vitrinite show the features of brittle failure, while those dominated by bitumen show the features of ductile failure. These microscale findings can support the upscaling model for precise prediction of mechanical properties at the macro scale, and assist with the understanding and interpretation of macroscopic elastic and fracture behavior in shale reservoirs.

How to cite: Zhao, J., Zhang, P., Zhang, W., and Zhang, D.: Influence of Geochemical Features on Elastic and Fracture Behavior of Organic Matter, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13701, https://doi.org/10.5194/egusphere-egu24-13701, 2024.

EGU24-14953 | ECS | Orals | EMRP1.2

Exploring Seismoelectric Interface Responses at Poroelastic/Elastic Boundaries: numerical and experimental approaches 

Natael Bernardo, Victor Martins-Gomes, Clarisse Bordes, and Daniel Brito

Seismoelectric effects, arising from the interaction between seismic waves and electromagnetic fields, have attracted considerable scientific interest for their potential applications in subsurface characterization, geothermal exploration, and hydrocarbon prospecting. While most of previous research has predominantly focused on fluid/poroelastic and poroelastic/poroelastic interfaces, there has been a notable knowledge gap regarding the behavior of seismoelectric signals at poroelastic/elastic interfaces, a crucial aspect in many geological scenarios. This study addresses this gap by providing concrete evidence of interface responses within poroelastic/elastic transitions through experimental measurements of seismoelectric coseismic and interface responses. The experiments were conducted using a plastic container filled with Landes sand as the poroelastic medium, saturated  with NaCl. The container featured distinct interfaces with four different elastic media: glass, plastic, aluminium, and granite, as well as a poroelastic medium (Vosges sandstone) for comprehensive analysis.

The experiments were conducted separately for each interface, with specific focus on two different pore fluid conductivities (36 μS/cm and 100 μS/cm). Furthermore, numerical simulations enable a direct comparison between experimental data and theoretical predictions, leading to an excellent agreement between measured and simulated  data in particular regarding the amplitude and polarity of the seismoelectromagnetic signal generated at poroelastic/elastic interfaces. The present demonstration of the electromagnetic signature at poroelastic/elastic boundaries contribute to the overall understanding of seismoelectric phenomena, enhancing the toolkit available to geophysicists and improving the accuracy of subsurface assessments. 

How to cite: Bernardo, N., Martins-Gomes, V., Bordes, C., and Brito, D.: Exploring Seismoelectric Interface Responses at Poroelastic/Elastic Boundaries: numerical and experimental approaches, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14953, https://doi.org/10.5194/egusphere-egu24-14953, 2024.

EGU24-15168 | ECS | Orals | EMRP1.2

Mechanical characterization of Freiberger Gneiss (Reiche Zeche, Germany) from laboratory to field scale 

Evangelos Korkolis, Elisabeth Kozlov, Bernard Adero, and Joerg Renner

Reservoir rock properties play an important role in the overall efficiency of petrothermal systems. Potentially interesting target formations for such systems include igneous and metamorphic rocks. For such lithologies with typically low porosity values, pre-existing fractures and foliation emerge as possible controlling factors of their hydraulic and mechanical behavior, respectively. Understanding the hydromechanical behavior of the reservoir rock is vital for the planning, execution and monitoring of hydraulic stimulation and exploitation, and continued safe operation. We inferred the elastic behavior of Freiberger gneiss from millimetre to tens of meters scale from laboratory and field measurements. Laboratory measurements were performed on samples prepared from blocks collected in the Reiche Zeche mine in Freiberg, Germany, and on cores retrieved from boreholes, drilled to perform hydraulic stimulation experiments as part of the STIMTEC (STIMulation TEChnologies) project. Controlled-source, P- and S-wave ultrasonic measurements were performed on samples and cores at room pressure and temperature conditions, covering a wide range of angles between wave-propagation direction and foliation, to characterize the degree of mechanical anisotropy of the gneiss. Magnitude and anisotropy of P-wave velocities determined from the laboratory measurements on the cores are in broad agreement with velocities calculated from in-situ sonic log measurements and active ultrasonic transmission experiments  (Boese et al., 2022) representing travel path lengths from meter to decameters in the rock mass, with a mean fracture distance of decimeters. At elevated pressures, ultrasonic measurements on cylindrical samples suggest the dominance of foliation over microcracks in determining the elastic behavior. The lack of a substantial reduction in velocities, deduced from in-situ active and passive microseismic analyses (Boese et al., 2022), except in highly deformed volumes, constrains the stiffness of the in-situ fractures.

Reference
Boese, C. M., Kwiatek, G., Fischer, T., Plenkers, K., Starke, J., Blümle, F., Janssen, C., and Dresen, G.: Seismic monitoring of the STIMTEC hydraulic stimulation experiment in anisotropic metamorphic gneiss, Solid Earth, 13, 323–346, https://doi.org/10.5194/se-13-323-2022, 2022.

How to cite: Korkolis, E., Kozlov, E., Adero, B., and Renner, J.: Mechanical characterization of Freiberger Gneiss (Reiche Zeche, Germany) from laboratory to field scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15168, https://doi.org/10.5194/egusphere-egu24-15168, 2024.

EGU24-15600 | ECS | Posters on site | EMRP1.2

Petrophysical rock typing integrated workflow in a Chilean greensand. 

Daniela Navarro-Perez, Quentin Fisher, Piroska Lorinczi, Jose Valderrama Puerto, Anibal Velasquez Arauna, and Martin Verdugo Dobronic

Petrophysical rock typing (PRT) is a key integrated workflow in reservoir characterization that utilizes petrophysical properties like permeability and porosity in conjunction with pore size distribution, typically derived from mercury capillary pressure measurements to classify from rich to poor reservoir quality rock units. However, the PRT workflow must encompass additional properties such as mineralogy, surface area, and clay distribution in tight rocks with a high clay mineral content to capture the microstructure and heterogeneity in such formations.

This case study focuses on the Zona Glauconitica (ZG) reservoir in the Magallanes basin, Chile, greensand with permeability ranging from 0.001 to 1 mD and total porosity between 10 and 25%v/v. Its high iron content is due to substantial amounts of chlorite and/or glauconite. The PRT workflow analyses ten petrophysical and mineralogical parameters using principal component analysis and K-means clustering, aiming to identify crucial patterns and correlations between rock properties and their storage potential. Multilinear regression (MLR) analysis was employed to determine the best-fit correlation for predicting pore throat radius at different mercury saturations from capillary pressure curves, using total porosity and gas permeability as input variables.

Four distinct petrofacies were identified as closely associated with clay minerals content, iron levels, permeability, porosity, and pore throat distribution. MLR best correlated the pore throat radius at 25%v/v mercury saturation with Pittman’s (1992) correlation. These findings offer significant promise as they contribute to enhancing and refining the existing petrophysical model. Future work extends this methodological approach to logging data across ten uncored wells, preceded by a validation process involving two cored wells. This iterative process will contribute to developing and validating an effective petrophysical model for the ZG reservoir, facilitating more precise and efficient evaluations of its production potential.

Pittman, E. D. 1992. Relationship of porosity and permeability to various parameters derived from mercury injection-capillary pressure curves for sandstone. AAPG Bulletin, 76, pp.  191-198.

How to cite: Navarro-Perez, D., Fisher, Q., Lorinczi, P., Valderrama Puerto, J., Velasquez Arauna, A., and Verdugo Dobronic, M.: Petrophysical rock typing integrated workflow in a Chilean greensand., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15600, https://doi.org/10.5194/egusphere-egu24-15600, 2024.

EGU24-16309 | ECS | Posters on site | EMRP1.2

Fault reactivation in clay-rich rocks – effects of water-clay interactions 

Markus Rast, Claudio Madonna, Paul A. Selvadurai, Antonio Salazar Vásquez, Quinn Wenning, and Jonas B. Ruh

Clay-rich rocks play an important role in critical practical applications, particularly as natural barriers in nuclear waste repositories and subsurface caprocks for CO2 storage. The interaction between electrostatically charged clay minerals and polar fluids (e.g., water) can lead to swelling or, under confined conditions, build-up of swelling stress. Fault closure by swelling in clay-rich rocks has been the focus of many studies. However, it remains unclear how water-clay interactions affect the stability of pre-existing faults, considering that in addition to changes in frictional properties, the stress state may also change due to the build-up of swelling stress.

This study addressed this gap by conducting triaxial friction experiments on oblique saw-cut cylindrical samples. The upper half of the sample consisted of a clay-rich rock (Opalinus claystone) and the lower half of a permeable sandstone (Berea sandstone). The first set of experiments determined the friction slip envelope of the sandstone-claystone interface without fluid injection, at confining pressures ranging from 4 to 25 MPa, and a constant axial loading rate of 0.1 mm/min. These experiments showed a frictional strength well below Byerlee’s law, indicating that the Opalinus claystone dictates the strength of the two-material interface.

Friction experiments with fluid injection were then performed at confining pressures of 10 and 25 MPa with a constant piston position (no axial loading) and an initial differential stress of about 70% of the expected yield stress. The aim was to compare the fluid pressures required to initiate slip in scenarios with and without fluid-clay interactions. For this, the experiments involved stepwise increases in fluid pressure through the injection of either deionized water (a polar fluid) or decan (a non-polar fluid). In one of the decane and one of the water injection experiments, fibre-optic strain sensors were attached to the sample surface. This allowed us to differentiate between poroelastic deformation within the matrix, deformation due to water-clay interaction, and elastic relaxation due to slip along the saw cut.

The friction slip envelope based on decane injection experiments is within the uncertainty of the friction slip envelope based on the experiments with no fluid injection. In contrast, the water injection experiments indicate a weakening of the frictional interface. We interpret this weakening to be due to the transition of the claystone from a solid rock to a mud close to the saw-cut surface. This weakening was evident even at ambient fluid pressure, although the apparent stress state was below the yielding stress, indicating the need to consider swelling stress in initial water injection scenarios. In summary, our data suggest that water-clay interactions may reactivate pre-existing faults due to (1) the change of the frictional properties and (2) the build-up of swelling stress.

How to cite: Rast, M., Madonna, C., Selvadurai, P. A., Salazar Vásquez, A., Wenning, Q., and Ruh, J. B.: Fault reactivation in clay-rich rocks – effects of water-clay interactions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16309, https://doi.org/10.5194/egusphere-egu24-16309, 2024.

EGU24-18323 | Posters on site | EMRP1.2

Combining Spectral Induced Polarization and X-ray micro-Computed Tomography imaging to reveal pore-scale dynamic processes occurring in volcanic hydrothermal systems 

Hamdi Omar, Tom Bultreys, David Caterina, Frédéric Nguyen, Lore Vanhooren, Sojwal Manoorkar, and Thomas Hermans

Many volcanoes host a hydrothermal system,  responsible for a large fraction of volcanic eruption. These eruptions do not expel magma but involve the forceful ejection of pre-existing rocks, volcanic gases, and steam, posing a significant threat to human safety. Recent catastrophic incidents underscore the difficulty in foreseeing sudden hydrothermal explosions, exposing our limitations in prediction. The challenge lies in the absence of distinct precursory signals, making it difficult to anticipate these events. These eruptions may be triggered by the introduction of mass and energy originating from magma, or alternatively, by the development of mineralogical seals above vents, devoid of any direct magmatic influence. Understanding and predicting these hydrothermal phenomena remain critical for mitigating their potential human and environmental impacts.

In the ERUPT research project, we study the geoelectrical response of volcano hydrothermal systems (VHS).  Here, we focus on the laboratory scale, where we amalgamate electrical properties, namely SIP (Spectral Induced Polarization) measurements, with X-ray pore-scale (4D µCT) imaging to unravel the intricate electrical signatures of volcanic systems on rock samples collected from Gunnuhver region (Iceland). SIP  is a geophysical method that measures the complex electrical impedance of a material as a function of a wide range of frequencies (Zimmermann et al., 2008). It is particularly useful for characterizing the electrical properties of porous media, and have been widely used to study rock samples from VHS (e.g., Lévy et al., 2019). SIP responses are sensitive to factors like surface area, pore size distribution, fluid content, as well as movement of fluids within the rock. On the other hand, X-ray µCT is an imaging technique that uses X-rays to create detailed, 3D images of the internal structure of a sample, such as internal morphology, porosity, other structural features of rocks at a micrometer scale, and quantify fluid pathways and flow dynamics within the rock. The synergy of combining these two methods can provide a more comprehensive understanding of the geoelectrical properties and internal structure of a rock sample as follow: by analyzing SIP responses at different frequencies and correlating them with the µCT images, we gain insights into how variations in geoelectrical properties relate to the movement of fluids within the rock matrix, as well as the influence of alteration or precipitation of minerals. As a first step, we developed a unique experimental set-up that enables to combine both methods (SIP and µCT) simultaneously. The noval prototype was thoroughly designed following specific technical features (e.g., dimensioning, materials) to ensure an optimal SIP signal acquisition under well controlled conditions of temperature and pressure, together with a high resolution 4D µCT imaging. This integrated approach is valuable for studies in geophysics, hydrogeology, and reservoir characterization, among other various relevant domains.

 

References

Lévy, L. et al. (2019) ‘Electrical resistivity tomography and time-domain induced polarization field investigations of geothermal areas at Krafla, Iceland: Comparison to borehole and laboratory frequency-domain electrical observations’, Geophysical Journal International, 218(3), pp. 1469–1489. https://doi.org/10.1093/gji/ggz240.

Zimmermann, E. et al. (2008) ‘A high-accuracy impedance spectrometer for measuring sediments with low polarizability’, Measurement Science and Technology, 19(10). https://doi.org/10.1088/0957-0233/19/10/105603.

How to cite: Omar, H., Bultreys, T., Caterina, D., Nguyen, F., Vanhooren, L., Manoorkar, S., and Hermans, T.: Combining Spectral Induced Polarization and X-ray micro-Computed Tomography imaging to reveal pore-scale dynamic processes occurring in volcanic hydrothermal systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18323, https://doi.org/10.5194/egusphere-egu24-18323, 2024.

We investigate the evolution of poro-mechanical, transport properties and strength characteristics of different sandstones during the cyclic underground hydrogen storage (UHS). Therefore, we selected three different types of sandstones: fine-grained St Bees (∅ =19~22%), coarse-grained Castlegate (∅=18~20%), and coarse-grained Zigong (∅=7~11%). These sandstones exhibit significant porosity, grain size, and mineralogical differences. The samples were imaged using micro-CT to characterise their initial microstructure and then subjected to cyclic loading experiments under hydrostatic as well as various deviatoric stress paths. The aim is to simulate the in-situ stress during cyclic UHS at depths of ~1.5-3km. The permeability of the samples was measured at different stress points. After completing the cyclic loading tests, we performed repeat micro-CT characterization as well as scanning electron microscopy (SEM) analysis to record the permanent changes in the microstructure caused by the stress cycles. The experimental results show that at shallower depths (low-stress state), the high porosity Castlegate sandstone (∅=18~20%) and the St Bees sandstone (∅=19~22%) exhibit an increase in elastic modulus during the tests, experiencing strain hardening due to compaction. The permeability of both sandstones decreases with an increase in mean stress, independent of the stress path. The fine-grained St Bees sandstone shows more significant accumulative inelastic strain and higher permeability loss than the coarse-grained Castlegate sandstone at the same stress state. In contrast, the low-porosity Zigong sandstone (∅=7~11%) shows no significant changes in mechanical properties, and its permeability loss is related to the closure of the initial microcracks. At greater depths (high-stress conditions), the mechanical and transport properties of the fine-grained St Bees sandstone exhibit an evident dependence on the stress path. During stress cycling under deviatoric stress conditions, the rock experienced a noticeable weakening indicated by a reduction in elastic modulus. The porosity of the sandstone decreased by 0.8~1.4% due to the combined effects of compaction and dilatancy, with a permeability loss exceeding 50%. The application of deviatoric stress led to lower permeability than hydrostatic tests conducted under the same mean stress. In contrast, the coarser-grained Castlegate and Zigong sandstones show an insignificant stress path dependence in their mechanical and transport properties. Due to compaction, these sandstones experience increased intergranular contact, leading to reduced porosity, increased elastic modulus, and strain hardening. The lower-porosity Zigong sandstone shows a higher sensitivity of permeability to stress than the higher-porosity Castlegate sandstone, which is related to its more complex pore structure. Microstructural analysis reveals that factors such as porosity, particle size, microfractures, and the presence and distribution of compliant components like clay minerals are the primary causes for the variations in the poro-mechanical and transport properties of the three sandstones under cyclic stress. Therefore, in addition to the depth of the reservoir, grain size (and their distribution) and mineralogical characteristics play a significant role in the selection of hydrogen storage candidates.

How to cite: Wen, M., Wang, Q., and Busch, A.: Evolution of poro-mechanical and transport properties of sandstones under different cyclic stress paths: Implications for underground hydrogen storage., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19226, https://doi.org/10.5194/egusphere-egu24-19226, 2024.

EGU24-20486 | ECS | Orals | EMRP1.2

Coupling Preferential Flow and Flow-induced Strain in Heterogeneous Rock-like Medium  

Arnold Bachrach and Yaniv Edery

Pressurized fluid injection into underground rocks occurs in applications like carbon sequestration, hydraulic fracturing, and wastewater disposal and may lead to human-induced earthquakes and to surface uplift. Yet, the full mechanical response of the underground to those injections is largely unknown. As the underground cannot be observed directly, experimental studies are crucial for understanding its mechanical reaction to fluid injection. Yet the need to maintain high pressure flow while tracking deformation complexes the execution of such experiments in comparison to standard mechanical tests. In this study we use a unique-transparent porous medium, made from chemically sintered Polymethyl Methacrylate (PMMA) beads, to simulate the underground rocks. We inject into the medium fluid at increasing pressure while measuring its internal plane-strain field as it deforms. We find that although the medium is constrained in its periphery, internal strains still occur perpendicular to the flow, compensated by the medium itself. While the medium’s overall strain shows clear reversibility, the internal perpendicular strain variations show very little to no recovery at all. Flow simulations over permeability fields, derived from the measured strain, reveal that internal strain variations have a significant impact on preferential flow within the medium. Together with the measured strain, the simulations results constitute a strong base for modeling the local heterogenous coupling between preferential flow and deformation in the underground due to fluid injections.

How to cite: Bachrach, A. and Edery, Y.: Coupling Preferential Flow and Flow-induced Strain in Heterogeneous Rock-like Medium , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20486, https://doi.org/10.5194/egusphere-egu24-20486, 2024.

EGU24-20513 | Posters on site | EMRP1.2

An innovative method to qualitatively measure the wettability of sandstone reservoirs based on the sequential extraction and fluorescence analysis 

Haijun Yan, Zhongnan Wang, Keyu Liu, Jing Yu, Guoqiang Zheng, Lidan Ji, Yilong Li, and Yuxiang Zhang

Wettability is a key factor controlling the flow and distribution of multiphase fluids in reservoirs. The study of reservoir wettability is of great significance to understand the mechanism of oil and gas migration and improving oil and gas recovery. The oil reservoirs have various wetting characteristics, including water wet, neutrally wet and oil wet states. The conventional methods for reservoir wettability analysis, including the contact angle, Amott index and the USBM index, have been currently established in the petroleum industry. The contact angle method is relatively simple, but it is not suitable for the reservoir samples with complex mineral composition and strong heterogeneity. Amott and USBM method based on oil-water displacement are encountering problems such as long test time and large errors, when applied to low-permeability and tight reservoirs. This study takes the low-permeability and tight sandstone reservoirs in the Ordos Basin as an example. Based on the measurement of oil and water content in the rock using the nuclear magnetic resonance, the Amott-Harvey index was tested. Then the twin powder sample was sequentially extracted for 72 hours with the fluorescence spectrum of the extracted organic matter was tested every 12 hours. The fluorescence spectrum of the crude oil in the same production layer was also tested, and then the relationship between the fluorescence characteristics of the extracted organic matter and the Amott-Harvey index was analyzed. Finally, a new method for rapid and qualitative evaluation of reservoir wettability was established. The conclusions were as follows: (1) Crude oil represents the characteristics of free hydrocarbons in the reservoir, and its fluorescence spectrum has a fluorescence intensity peak around 375 nm. (2) The firstly extracted organic matter contains both free hydrocarbons and adsorbed hydrocarbons, and its fluorescence spectrum has a double peak with a wavelength of 375nm as the main peak and 460nm as a secondary peak. The last extracted organic matter has a lower proportion of free hydrocarbons and a higher proportion of adsorbed hydrocarbons compared with firstly extracted one. The fluorescence spectrum mostly shows double peaks with the same fluorescence intensities at the wavelength of 375nm and 460nm. (3) The ratio of fluorescence intensity of the extracted organic matter at a wavelength of 460nm to 375nm (I460nm/I375nm) may reflect the coverage proportion of the rock surface by adsorbed hydrocarbons, and thus can be used as a parameter indicating the wettability of the rock. The I460nm/I375nm value of the last extracted organic matter has a strong correlation with the Amott-Harvey index, therefore it can be used to qualitatively evaluate the reservoir wettability.

How to cite: Yan, H., Wang, Z., Liu, K., Yu, J., Zheng, G., Ji, L., Li, Y., and Zhang, Y.: An innovative method to qualitatively measure the wettability of sandstone reservoirs based on the sequential extraction and fluorescence analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20513, https://doi.org/10.5194/egusphere-egu24-20513, 2024.

EGU24-2753 | Orals | HS8.1.1

Release and Transport Characteristics of Heavy Metal Pollutants in Tailings Pond 

Jiaxu Jin, Pengfei Wu, Hongzhi Cui, and Xinlei Zhang

The lead-zinc tailings pond contains a significant concentration of heavy metal pollutants, such as lead, zinc, copper, chromium, cadmium, mercury, and arsenic. These pollutants exist in the form of ions within the tailings. External environmental factors can facilitate the release and transportation of these heavy metal elements from the tailings, resulting in pollution. The factors influencing pollutant release and variations in heavy metal tailings transport across different media were investigated by employing statistical analysis, leaching tests, and heavy metal soil column experiments based on the results of a case study on the Qingshan lead-zinc mining area. The multi-component solute release transport model for tailings to examine the interplay between concentration and seepage fields was constructed by considering hydrodynamics, mass transfer, and chemical reactions. The COMSOL software was performed to develop a customized model for the transport of heavy metal pollutants, wherein specific boundary conditions were set to enable quantitative analysis and interpretation of the release and migration of heavy metal solutes in tailings. The present study establishes a foundation for comprehending the migration patterns, pollution pathways, and mechanisms of heavy metal pollutants in tailings ponds. Furthermore, it provides indispensable technical support for addressing heavy metal contamination in lead-zinc mining regions and developing impermeable systems for tailings ponds.

How to cite: Jin, J., Wu, P., Cui, H., and Zhang, X.: Release and Transport Characteristics of Heavy Metal Pollutants in Tailings Pond, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2753, https://doi.org/10.5194/egusphere-egu24-2753, 2024.

Simulations of two-phase flow in heterogeneous porous media are crucial for several applications, such as CO2 sequestration, efficient oil and gas recovery, and groundwater pollution remediation. Modeling of two-phase flow systems becomes very challenging when capillary heterogeneity and hydraulic discontinuities are considered. Traditional models use numerical techniques such as finite difference, finite element, and finite volume for solving the partial differential equations of the system. Although numerical methods have been shown to produce reliable solutions for complex flow problems, they can become computationally expensive. This emphasizes the high computational demand for solving the inverse problem. The use of DNNs (deep neural networks) has become more common in predicting subsurface flow behavior. DNNs is a data-driven approach that enables the learning of a system by linking input and output parameters and provides fast predictions of dynamic, complex systems. Nevertheless, when data is extremely scarce, particularly in subsurface systems, standard DNNs are unable to yield robust results. Recent advancements enable the integration of physical constraints as partial differential equations (PDEs) into the DNNs scheme. Such a class of deep learning techniques is generally referred to as physics-informed neural networks (PINNs). PINNs are also capable to provide forward solutions for PDEs.  In this work, we examined PINNs' capabilities to provide forward solutions of a 1D steady-state two-phase flow with capillary heterogeneity at the sub-core scale. Here, we trained a PINNs system that incorporates high variability in the hydraulic properties and boundary conditions implemented as input parameters. We compared the PINNs results with numerical solutions to test the efficiency of the developed PINNs system. Results have shown that the trained PINNs system could reproduce both capillary pressure and phase saturation profiles for altering fractional flows, injection rates, hydraulic properties, and domain lengths with high accuracy and within a single training. Training the extended PINNs system was obtained in a few hours, and the post-trained system provided unlimited solutions for variable structures and boundary conditions within a few seconds. 

How to cite: Chakraborty, A. and Moreno, Z.: Simulating two-phase flow using Physics-informed neural networks with capillary heterogeneity and hydraulic discontinuities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3458, https://doi.org/10.5194/egusphere-egu24-3458, 2024.

The power mean is the generalization of the common averaging methods, such as harmonic, geometric and arithmetic mean, but also minimum and maximum. However, it also allows an infinite number of other means between these common means and can therefore be adapted very flexibly to the specific task of upscaling. This will be demonstrated in the contribution by calculating the effective thermal conductivity as the mean of the partial conductivities of soil components (typically of the solid, liquid, and gaseous phase). Soil thermal conductivity is a key factor for the soil heat balance and is widely used in many fields of science. However, it is elaborate to measure thermal conductivity of soils that have different porosities and degrees of saturation. Effective thermal conductivity of soil strongly depends on the arrangement of particles (soil structure) and on the interaction of added water to the solid phase (e.g., menisci).  To improve the prediction of soil thermal conductivity, specific information of soil structure needs to be taken into account. The relationship between the power mean exponents p and the degree of saturation is an indicator of the existing soil structure.

How to cite: Stange, C. F.: On the possibilities of the power mean as an upscaling method using the example of thermal conductivity in soil, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3853, https://doi.org/10.5194/egusphere-egu24-3853, 2024.

EGU24-4162 | Orals | HS8.1.1

Impact of an immobile, mobile and permeable phase on mixing-driven reactions in porous media 

Joaquin Jimenez-Martinez, Xueyi Zhang, Ishaan Markale, Dorothee Kurz, Zhi Dou, Maxence Carrel, Veronica Morales, and Markus Holzner

Understanding chemicals mixing and reactions in porous media is critical for many environmental and industrial applications. In the presence of a non-wetting immiscible phase (e.g., gas) within the pore space, it can remain immobile, giving rise to the so-called unsaturated flow, or it can move, resulting in a multiphase flow. In other cases, the immiscible phase can be permeable, as it occurs with biofilms growing within the pore space. We combine experiments and numerical modeling to assess the impact of saturation (fraction of the pore volume occupied by the wetting phase), multiphase flow (stationary two-phase flow), and the presence of permeable biofilm within the pore space on mixing-driven reactions. The product formation is larger for a given flow rate as saturation decreases, while for a given Peclet, it is the opposite. In multiphase flow conditions, for a given flow rate of the wetting phase, the product formation depends on the flow rate of the non-wetting phase. In the presence of biofilms, the product formation is enhanced compared to their absence and is further enhanced with a heterogeneous permeability within the biofilm.

How to cite: Jimenez-Martinez, J., Zhang, X., Markale, I., Kurz, D., Dou, Z., Carrel, M., Morales, V., and Holzner, M.: Impact of an immobile, mobile and permeable phase on mixing-driven reactions in porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4162, https://doi.org/10.5194/egusphere-egu24-4162, 2024.

Plutonium (Pu) in the subsurface environment can transport in different oxidation states as an aqueous solute or as colloidal particles. The transport behavior of Pu is affected by the relative abundances of these species and can be difficult to predict when they simultaneously exist. This study investigates the concurrent transport of Pu intrinsic colloids, Pu(IV)(aq) and Pu(V-VI)(aq) through a combination of controlled experiments and semi-analytical dual-porosity transport modeling. Pu transport experiments were conducted in a fractured granite to elucidate sorption processes and their scaling behavior. In the experiments, Pu(IV)(aq) was the least mobile of the Pu species, Pu(V-VI)(aq) had intermediate mobility, and the colloidal Pu, which consisted mainly of precipitated and/or hydrolyzed Pu(IV), was the most mobile. The semi-analytical modeling revealed that the sorption of each Pu species was rate-limited, as the sorption could not be described by assuming local equilibrium in the experiments. The model was able to describe the sorption of the different Pu species that occurring either on fracture surfaces, in the pores of the rock matrix, or simultaneously in both locations. While equally good fits to the data could be achieved using any of these assumptions, a fracture-dominated process was considered to be the most plausible because it provided the most reasonable estimates of sorption rate constants. Importantly, a key result of this work is that the sorption rate constant of all Pu species tends to decrease with increasing time scales, which implies that Pu will tend to be more mobile at longer time scales than observations at shorter time scales suggest. 

How to cite: Zhang, X.: Plutonium reactive transport in fractured granite: Multi-species experiments and simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4230, https://doi.org/10.5194/egusphere-egu24-4230, 2024.

Contamination with mono-aromatic hydrocarbons, specifically benzene, toluene, and xylenes (BTX), is one of the major concern to groundwater aquifers. BTX have high environmental stability and are harmful to human health and aquifer ecosystem. Thorough assessment and monitoring of the risk posed by BTX in aquifers are essential for the sustainable use of groundwater resources. The biodegradation of BTX in aquifer rely primarily on anaerobic processes. Nitrate-sulfate-reducing assemblages is considered for BTX bioremediation in such anoxic condition. These assemblages act as a terminal electron acceptor for bacterial respiration. The degree of the interaction between combinations of nitrate-sulfate reduction and BTX elimination determines the efficacy of BTX biological degradation. The interactions, however, received limited attention in the existing literature. Hence, the current analysis focuses co-existence of nitrate-sulfate assemblages affecting BTX bioremediation. A multi-component numerical simulation is performed to investigate the potential of nitrate-sulfate-assemblages for bioremediation of BTX in anoxic conditions. A fully implicit finite-difference novel approach is adopted here to solve the proposed numerical model, which is capable of obtaining spatial variation in BTX concentrations. The results suggest that bioremediation is efficient in removing toxic BTX from aquifers under the coexistence of nitrate-sulfate assemblages. This approach, in addition, can be used in deciding the optimum rate of electron acceptor injection and the time required to bring BTX to standard limits. Furthermore, it can help us to plan sustainable bioremediation strategies for mono-aromatic hydrocarbon contaminated aquifers where such reduction assemblages co-exist. This hydrogeobiochemical modelling study also emphasizes the importance of multidisciplinary methods in dealing with challenging environmental issues in the contaminated aquifers.

Keywords: Hydrogeobiochemical modelling; Bioremediation; BTX; Nitrate-sulfate assemblages; Aquifers.

How to cite: Srivastava, A., Valsala, R., and Jagadevan, S.: Hydrogeobiochemical Modelling for Bioremediation of Mono-Aromatic Hydrocarbons Using Nitrate-Sulfate-Reducing Assemblages in Aquifers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4243, https://doi.org/10.5194/egusphere-egu24-4243, 2024.

EGU24-4880 | ECS | Orals | HS8.1.1

Experimental Investigation on Dispersion Within Porous Media Influenced by Particle sizes and Pore-Scale Heterogeneity 

Jiyoung Baek, Byeong-Hak Park, Gabriel Rau, and Kang-Kun Lee

As heat tracing gains versatility in hydrogeological applications, precise thermal dispersion modeling becomes essential. However, limited experimental data for thermal dispersion, influenced by several factors such as particle size or shape, poses a challenge to the understanding of the relationship between flow velocity and thermal dispersion coefficient. To fill these gaps, the solute and heat tracer experiments were conducted using two different sizes of sand. Thermal and solute dispersion were analyzed by applying analytical models. We also systematically collected and revisited literature data to comprehensively interpret the influences of particle size, shape, and pore-scale heterogeneity on dispersion. The results exhibited that the solute and thermal dispersivity were comparable when the dispersion linearly increased to the velocity. However, within the transition regime (Pe < 5), a departure from linearity was observed (R2 < 0.9). The deviation was more pronounced in smaller particle size due to pore-scale heterogeneity arising from the complexity of pore network. Consequently, our findings emphasize the potential necessity for caution when modeling thermal dispersion based on solute dispersion within natural porous materials.

Keywords: Particle size; Thermal dispersion; Pore-scale heterogeneity; Transition regime; Sandbox experiment

 

Acknowledgements

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (No. 2022R1A2C1006696). This work was also supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government(MSIT) (No. 2022R1A5A1085103). This work was also supported by the Nuclear Research and Development Program of the National Research Foundation of Korea (NRF-2021M2E1A1085200).

 

How to cite: Baek, J., Park, B.-H., Rau, G., and Lee, K.-K.: Experimental Investigation on Dispersion Within Porous Media Influenced by Particle sizes and Pore-Scale Heterogeneity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4880, https://doi.org/10.5194/egusphere-egu24-4880, 2024.

This study experimentally demonstrates the impact of water and solute influx magnitude, and its resulting local distribution, on transport at timescales longer than the influx duration, through a disparate velocity field of a partially saturated domain. In a sand-filled cell, steady-state flow is maintained with a constant horizontal hydraulic head, while the upper part of the cell is partially saturated. The horizontal velocity varies by orders of magnitude from the surface to the saturated zone. An influx of water with a dissolved tracer is applied at the middle of the upper boundary surface, over several minutes, forming a plume that reaches a depth of a few centimeters. This influx disturbs the flow field locally, but after it is terminated, the return to steady-state flow is of the order of magnitude of the influx timescale. Eventually, the solute flows to the saturated zone and out of the cell through a path on the scale of decimeters, over a time scale of days. Employing ICP-MS as a sensitive measurement tool to detect highly diluted concentrations of solute enables tracking of a small influx volume that does not significantly perturb the flow field. This maintains a separation between the distinct spatial-temporal scales of the short-term local infiltration and the long-term system-scale transport. Applying varying influx magnitudes sets the solute plume across different velocity profiles and thus dictates the downstream plume distribution. A low influx relative to the hydraulic conductivity of the partially saturated sand allows solutes to infiltrate farther down compared to a higher influx, so that the plume reaches higher flow velocities but also spans a wider velocity variability. A higher influx relative to the hydraulic conductivity leads to a local increase in saturation, but a shallower depth of infiltration compared to the lower influx, and the system accordingly exhibits a more uniform plume located at a lower velocity region. In downstream solute concentration measurements, these influx variations result in a faster but more smeared breakthrough for the lower influx compared to a slower and more uniform breakthrough for the higher influx, corresponding to their initial distribution after infiltration.

How to cite: Kalisman, D., Dror, I., and Berkowitz, B.: From infiltration to steady-state flow in partially saturated media – bridging solute transport between millimeter-decimeter and minute-day scales, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5615, https://doi.org/10.5194/egusphere-egu24-5615, 2024.

EGU24-5866 | ECS | Posters on site | HS8.1.1

The Effect of Time-Varying Soil Properties Caused by Ploughing and Consolidation on Pesticide Fate in Soil and Groundwater 

Pavan Cornelissen, Louise Wipfler, Maarten Braakhekke, and Marius Heinen

Soil properties such as the dry bulk density and soil hydraulic parameters can significantly affect the environmental fate of pesticides. These properties are often assumed to remain constant in time in numerical models. In reality, however, these properties change over time due ploughing and consolidation. In this study, we modeled the time-varying soil properties induced by ploughing and consolidation and assessed its effect on pesticide accumulation in the topsoil and leaching to the groundwater. For this purpose, time-dependent soil properties have been implemented in the hydrological model SWAP and the pesticide fate model PEARL. Ploughing instantaneously decreases the bulk density, after which it gradually increases again to its original value due to consolidation caused by rainfall. The time-dependent soil properties are modelled based on empirical relationships between the dry bulk density and the Mualem-Van Genuchten parameters found in the literature.

Ploughing leads to a short-term deviation of the soil water content and concentration compared to the reference case (i.e., the case with constant soil properties). We included mixing of pesticide over the ploughing layer due to ploughing in both cases. However, under Central European climate conditions, the effect of ploughing vanishes within several months in the entire soil profile. For assessing the impact on the leaching of pesticide to groundwater, we evaluated the pesticide concentration in pore water at 1 meter depth. The effect of time-varying soil properties due to ploughing and consolidation on the leaching concentration was found to be small for both a tracer and an adsorbing solute. Even for an extreme case with three ploughing events per year, the effect on the 90th-percentile of daily leaching concentration was smaller than 0.3%. For assessing the impact on the exposure of soil organisms to pesticides, we considered the pesticide concentration in pore water averaged over the upper 20 centimeters of the soil. For the tracer, ploughing resulted in a 1.2% decrease of the 90th-percentile of daily topsoil concentration data for the extreme case of three ploughing events per year. Interpretation of the results for adsorbing solutes in the topsoil is hampered by the fact that soil mass is not conserved in the current approach. More advanced models must be developed that allow for conservation of soil mass for assessing the impact of time-dependent soil properties on concentrations in the topsoil.

How to cite: Cornelissen, P., Wipfler, L., Braakhekke, M., and Heinen, M.: The Effect of Time-Varying Soil Properties Caused by Ploughing and Consolidation on Pesticide Fate in Soil and Groundwater, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5866, https://doi.org/10.5194/egusphere-egu24-5866, 2024.

EGU24-7503 | Orals | HS8.1.1

Dynamics of aeration zone mobile inventory preshape groundwater quality evolution - results from multi-year sampling of regolith seepage  

Katharina Lehmann, Dinusha Eshvara Arachchige, Robert Lehmann, and Kai Uwe Totsche

The aeration zone (AZ) below the soils sensu stricto is still neglected compartment regarding its structure, diversity of life and habitats, and role for the provision of ecosystem services. Especially in thick AZ of topographic recharge areas, fluid flow dynamics and the exchange of the total mobile inventory (Lehmann et al. 2021) and their roles for the quality-evolution of groundwater are largely unknown. In the low-mountain topographic recharge area of the Hainich Critical Zone Exploratory (central Germany), we study spatiotemporal dynamics of the fluid fluxes and mobile inventory within the shallow (upper) AZ (regolith) and compare their signature with soil seepage and perched groundwater (deeper AZ). Percolates from 20 drainage collectors (DC) covering a diversity of Triassic mixed carbonate-siliciclastic (sedimentary) bedrock, soil types, and installation depths were sampled for more than 3 years on regular (monthly) and event-based basis and analyzed by various physico-/hydrochemical and spectro-microscopic techniques.

On average, the DC captured ~13% of the percolate from the forest topsoil seepage and 2.4% of precipitation. Seepage volume was mainly influenced by the factors soil thickness and sampling month, followed by scarp slope gradient and seasonal differences. In the upper AZ, the mobile inventory exhibited strong seasonality (e.g. EC, pH, nitrate, sulphate, K, Si, Mn, Al, Fe, particle concentration) and were more dependend on seasonal weather conditions and single (extreme) events (e.g., snow melt, rain events) than on lithology, followed by site-specific structural factors (location, slope), or pedological settings (e.g. overburden soil type, soil thickness). Generally, our results show fluid-rock interactions within the upper AZ with a more similar hydrochemical water signature to perched groundwater. Contrastingly, particulate mobile inventory showed a strong connection to soil seepage signature, comprising a diverse spectrum of mineral particles (mainly clay minerals) and mineral- and mineral-organic associations up to 160 µm, including aggregates and microorganisms. The different flow regimes that prevail during different seasons and weather conditions mainly influenced the amount and spectrum of percolate mobile inventory. During summer, dry periods in conjunction with extreme precipitation events favored translocation of small-sized particles. In winter, fast-flow regimes during normal precipitation as well as during snowmelts contributed strongly to the translocation of organic/inorganic carbon and mineral particle through the AZ and to groundwater. We conclude that the AZ is a complex biogeochemical reactor, that severely alters the percolate composition and properties, already preshaping the biogeochemical groundwater quality as well as due to its functions and services (e.g. water-purification and storage). As such, the aeration zone hast to be considered as a crucial compartment for groundwater quality evolution, especially in topographic recharge areas.

 

Lehmann, K., Lehmann, R., Totsche, K. U. (2021) Event-driven dynamics of the total mobile inventory in undisturbed soil account for significant fluxes of particulate organic carbon. Sci. Total Environ. 756, 143774, doi: https://doi.org/10.1016/j.scitotenv.2020.143774

How to cite: Lehmann, K., Eshvara Arachchige, D., Lehmann, R., and Totsche, K. U.: Dynamics of aeration zone mobile inventory preshape groundwater quality evolution - results from multi-year sampling of regolith seepage , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7503, https://doi.org/10.5194/egusphere-egu24-7503, 2024.

Two-phase flow in geological fractures holds significant relevance in various applications, including subsurface fluid storage and oil and gas exploitation. The pore-scale modelling of such flows is a challenging task influenced by many factors, such as the complex interplay between the viscous, capillary, gravitational and inertial forces, intricate geometries, as well as molecular scale phenomena such as moving contact lines and thin wetting films. Although various modelling approaches have been used to tackle these challenges, the high computational demands required to accurately capture the three-dimensional fluid-fluid interfacial dynamics often render these models impractical for real-world applications. Consequently, from a practical point of view, the simplification of these 3D models may become imperative to facilitate efficient and reasonably accurate predictions of flow quantities.

Depth-integrated two-dimensional modelling is one such approach which enables saving computational time and effort at the expense of not resolving the third dimension. Here, the governing equations are solved in two dimensions, the influence of the third dimension being incorporated through appropriate additional terms. While such models have been used previously, they have so far been restricted to either permanent single-phase flow in rough fractures or two-phase flow in 2D porous media of homogeneous depth. In a rough fracture, the fluid-fluid interface possesses not only an in-plane curvature but also an out-of-plane curvature, which must be accommodated in the 2D depth-integrated model. Therefore, to address the immiscible flows in rough fractures it is essential to reformulate the 2-D depth-integrated approach from the first principles.

To perform the depth integration, we proceed from the traditional direct numerical simulation (DNS) approach, where the Navier-Stokes equations, coupled with an interface capturing technique, which in our case is the Volume of Fluid (VOF), are solved numerically. We integrate the governing flow equations in the vertical direction while expressing the flow fields in terms of 2D depth-averaged flow quantities. To account for the out-of-plane curvature and the wall shear stress arising from the no-slip conditions on the fracture walls, we assume locally a plane Poiseuille configuration (Hele-Shaw). 

The derived 2D depth-integrated model is implemented in the open-source CFD code OpenFOAM. We validate our model using the Saffman-Taylor instability case, comparing predictions with experiments and full 3D model results. We then extend our study to two numerically generated rough fractures with (a) smoothly and periodically varying aperture and (b) a more realistic aperture field with a larger roughness. We investigate drainage (i.e., the displacement of the wetting fluid by the non-wetting fluid) over a range of Capillary numbers spanning more than three orders of magnitude. We compare our 2D model predictions of both, pore-scale and macroscopic flow variables, with those obtained using 3D simulations. Our 2D model accurately estimates key statistical indicators with a tenfold reduction in computation time, offering an excellent compromise between solution accuracy and computational efficiency. We also discuss the limitations of the depth-averaged model depending on flow ranges.

How to cite: Krishna, R., Meheust, Y., and Neuweiler, I.: Depth-integrated Two-dimensional Model for Immiscible Two-phase Flow in Open Rough-walled Fractures with Smoothly Varying Aperture, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7889, https://doi.org/10.5194/egusphere-egu24-7889, 2024.

Evaporation of soil water depends not only on climatic conditions, soil texture, and soil hydraulic properties but also on the soils’ macro-structure. Often, evaporation is characterised by water losses over time for a defined soil volume where soils are assumed to be homogeneous in texture and structure. In this study, we investigated the potential and limitations of 3D modelling of evaporation processes on soil cores with structural features ≥ 480 µm determined by X-ray computed tomography (X-ray µCT). The method was tested for two contrasting soil structures (ploughed vs. non-ploughed grassland) which experienced structural changes due 19 cycles of freezing and thawing. For all real soil samples, we simulated three different conditions of atmospheric demand with Hydrus 3D. It was hypothesised that the different distribution of air-filled macro-pores, the macro-connectivity of soil matrix and the surface area will affect bare soil evaporation and more specific the transition from stage 1 to stage 2 evaporation. To evaluate the effect of soil macro-structure on the column scale, we investigated the spatial distribution of water content and water fluxes. The combination of X-ray µCT and HYDRUS 3D was able to capture the effect of ploughing and freezing-thawing on soil macro-structure and to quantify the effect on the water dynamics inside the samples for various atmospheric demands and thus the feedback with evaporation.

How to cite: Leuther, F. and Diamantopoulos, E.: The effect of soil macro-structure on bare soil evaporation – using HYDRUS 3D simulation on X-ray µCT determined soil structures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8091, https://doi.org/10.5194/egusphere-egu24-8091, 2024.

EGU24-8793 | Posters on site | HS8.1.1

Advancing Irrigation Strategies: Synergistic Modeling of Soil Moisture Using Cosmic-Ray Neutron Sensing, Hydrus-1D, and Machine Learning 

Salvatore Straface, Guglielmo Federico Antonio Brunetti, and Andrea Scozzari

Innovative monitoring techniques today facilitate advanced and reliable measurements in the vadose zone. This, coupled with the predictive capabilities of machine learning, has an ever-growing impact on the management of agricultural and irrigation practices. The vadose zone, particularly the root zone, plays a pivotal role in hydrological processes by regulating water and energy fluxes across the soil surface. Additionally, it influences nutrient transport, groundwater recharge, groundwater pollution, microbial activity, and plant physiology, as it links the atmosphere, soil, and groundwater. Among various monitoring techniques, Cosmic-Ray Neutron Sensing (CRNS) stands out as a ground-based remote sensing technique capable of measuring soil moisture within the root zone at relevant scales (up to 240 m) with a high level of reliability. It is based on nuclear interactions between incoming cosmic rays and elements in the Earth’s atmosphere, such as hydrogen. By employing the Hydrus-1D Cosmic module, effective soil moisture values can be derived based on the neutron intensity detected by Cosmic-Ray Neutron Probes (CRNPs). On the other hand, machine learning methods and neural networks (NN) hold enormous potential despite inherent limitations, notably the requirement for extensive datasets and their lack of a physical foundation in reproducing soil processes. In this study, we propose a synergistic approach to overcome these limitations. The physically-based Hydrus-1D model was utilized to train a single-layer NN for the direct prediction of soil moisture and irrigation water demand, relying exclusively on atmospheric forcings (temperature and precipitation) as input. In a proof-of-concept aimed at assessing the validity and robustness of our approach, a time series of synthetic data replicating soil characteristics, atmospheric forcings, and field measurements conducted through CRNPs was generated. These data were employed in the Hydrus-1D Cosmic module to calibrate a physically-based model, facilitating the generation of a continuous and extensive spatiotemporal soil moisture output dataset for the simulated synthetic field. The single-layer NN, trained with this synthetic soil moisture and atmospheric forcing data, demonstrated the potential to accurately predict soil moisture and irrigation needs of the terrain straightforwardly, using only atmospheric variables as input. The proposed synergistic approach has exhibited significant potential, and future developments in this research will involve the incorporation of real data.

How to cite: Straface, S., Brunetti, G. F. A., and Scozzari, A.: Advancing Irrigation Strategies: Synergistic Modeling of Soil Moisture Using Cosmic-Ray Neutron Sensing, Hydrus-1D, and Machine Learning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8793, https://doi.org/10.5194/egusphere-egu24-8793, 2024.

EGU24-9159 | ECS | Orals | HS8.1.1

Assessing glyphosate movement through different agricultural systems with a shallow water table: insights from an inverse dual permeability model 

Giovanna Piazzon, Matteo Longo, Sebastiano Rocco, Francesco Morari, and Nicola Dal Ferro

The movement dynamics of glyphosate (GLY) in soil can be highly complex and challenging to predict, because its high water solubility and strong propensity to soil particle adsorption can interact with agricultural management practices, e.g. tillage operations and water table management. This can make GLY i) sensitive to nonuniform leaching via preferential flow paths into the groundwater before it can degrade, ii) difficult to model according to uniform flows. The aim of this study was to understand GLY dynamics in different agricultural systems of the low-lying Venetian plain, by calibrating a dual permeability model embedded in HYDRUS-1D using a series of GLY experimental data that were collected in the field, and compare it with a dual porosity mobile-immobile approach. Experimental data came from eight drainable lysimeters, where two shallow water table depths (60 cm and 120 cm deep) were compared in conventional (CV) and conservation agriculture (CA) systems as representative of the low-lying Venetian plain conditions (NE Italy). On May 2019, GLY and a tracer (KBr) were applied on bare soil (in CV) and rye that was used as a cover crop, in CA. After the distribution, soil (0-5, 5-15 cm deep) and soil-pore water (15, 30, 60 cm deep) samples were collected for 48 days to follow solutes dynamics. At the same depths, soil moisture and matric potential were monitored using TDR probes and electronic tensiometers. An automated system modulated the suction through matric potential readings combined with an electronic vacuum regulator. The HYDRUS 1-D software package was employed for inverse modelling of soil properties, first through parameterization and matric potential results, while solute movement parameters were calibrated based on GLY and KBr results from soil and water samples. Experimental results showed that GLY was found at different depths, especially soon after its distribution as dependent on intense rainfall events. The MIM model failed to predict any GLY movement, due to its high adsorption coefficient that hindered any GLY exchange between the immobile and mobile phases. In fact, experimental observations revealed that a preferential flow occurred down to the deepest layers (60 cm deep), even in the presence of poorly structured soil and irrespective of both the groundwater level and the cultivation system. In contrast, the dual permeability model provided a more accurate description of GLY dynamics in soil, successfully predicting the observed bypass flow timing experiment. Therefore, dual permeability model seems crucial for describing GLY dynamics in agroecosystems, enabling more accurate predictions of its potential pathways. 

How to cite: Piazzon, G., Longo, M., Rocco, S., Morari, F., and Dal Ferro, N.: Assessing glyphosate movement through different agricultural systems with a shallow water table: insights from an inverse dual permeability model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9159, https://doi.org/10.5194/egusphere-egu24-9159, 2024.

EGU24-9503 | ECS | Orals | HS8.1.1

Reservoir characterization by push-pull tests employing Kinetic Interface Sensitive tracers 

Huhao Gao, Alexandru Tatomir, Hiwa Abdullah, and Martin Sauter

The kinetic interface-sensitive (KIS) tracer test is a newly developed tracer approach to measure the fluid-fluid interfacial area (IFA) during dynamic two-phase flow in porous media. This new tracer approach can be applied for multiple geological applications, where dynamic two-phase flow is involved, e.g. monitoring the plume during geological storage of carbon dioxide. The obtained concentration breakthrough curves by measuring reacted tracer concentration in water samples are interpreted with a specialized Darcy-scale numerical model to determine the IFA. The previous design of the drainage experiments has one major limitation that the volume of the usable water sample after breakthrough for the measurement is often insufficient. An alternative is to employ KIS tracers in a “push-pull” experimental set-up, i.e. primary drainage is followed by a consequent main imbibition process, with the flow direction being reversed. This study applies both the pore-scale numerical simulation and the core-scale column experiments to study the KIS tracer reactive transport during push-pull processes. The pore-scale numerical simulation is done with a phase-field method-based continuous species transport model. The reactive transport of the tracer and the characteristics of the concentration breakthrough curves are analyzed. The Darcy-scale reactive transport model is validated by comparing it to the pore-scale results. Finally, the new method is applied in the column experiment, where the determined specific interfacial area is found to be close to the literature data.

How to cite: Gao, H., Tatomir, A., Abdullah, H., and Sauter, M.: Reservoir characterization by push-pull tests employing Kinetic Interface Sensitive tracers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9503, https://doi.org/10.5194/egusphere-egu24-9503, 2024.

Soils are complex systems where different physical, chemical and biological processes occurring simultaneously and interact in a non-linear way. This includes the diffusion process, which is known to be affected by the tortuosity, and therefore the water content. Additionally, the high degree of soil heterogeneity poses significant challenges in studying soil reactivity due to its high impact on mixing. In this study we evaluate the effect of a series of what we could be key controlling factors of effective reaction rates in soils at the plot scale: the degree of heterogeneity, the hydraulic structure, the reaction rate, the initial distribution of reactants, and the heterogeneity in the diffusion coefficient.

We tackle this by explicitly simulating hypothetical biomolecular soil reaction (A+B C) for different degrees of heterogeneity, different hydraulic structures, different reaction rates, different initial distribution of the reactants and different representation of diffusion. Results are evaluated in terms of effective reaction rates at the plot scale.

The simulation results reveal that mixing conditions control reactions in unsaturated soils. Non-ideal reactivity due to mixing-limited conditions is not only a consequence of the simple presence of heterogeneity or even of its intensity. Instead, it results from (at least): the characteristics of heterogeneity, the Pe number, the Da number, the spatial distribution of the reactants. Interestingly, the spatial variability of the (tortuosity-dependent) diffusion coefficient appears to also have a significant effect on mixing conditions.  

By these results, we illustrate the high complexity of reactive systems in unsaturated soils, which makes the use of average macroscopic reaction rates (as in most agriculture, environmental and geoengineering models) at least questionable.

How to cite: Henri, C. and Diamantopoulos, E.: What control reactions in unsaturated soils? On the dynamic effect of small-scale heterogeneity and (spatially variable) diffusion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9957, https://doi.org/10.5194/egusphere-egu24-9957, 2024.

EGU24-10423 | ECS | Posters on site | HS8.1.1

Disentangling nitrogen turnover in Nature Based Solutions: hydrodynamic properties and reactive behavior  

Ludovica Presta, Giuseppe Brunetti, Christine Stumpp, Michele Turco, and Patrizia Piro

Nature Based Solutions (NBS) are known to play a key role in urban water management by increasing the infiltration, retention, and evapotranspiration capacity of urban areas. However, their potential use for contaminant removal has only been partially investigated. To address this issue, this study presents an experimental analysis of the nitrogen turnover in selected typical NBS substrates. Soil column experiments were combined with laboratory methods to characterize the hydrodynamic properties of porous media and elucidate the nitrification process in NBSs. In a first experimental campaign, saturated soil columns were injected with a natural tracer (deuterium) to characterize non-reactive solute transport in different substrates. Breakthrough curves exhibit significant tailing, thus suggesting the existence of a complex interplay between a mobile and an immobile domain. A second experimental campaign was carried out in larger unsaturated soil columns periodically injected with wastewater. Nitrogen species were measured in the effluent to describe the nitrogen turnover in soils. Results are characterized by two distinct phases, in which nitrate is initially not detectable in the outflow but later becomes the dominant species. This behavior indicates the existence of an initial microbial adaptation phase, followed by an efficient nitrification process supported by the oxic conditions in the substrate. Altogether, observations highlight the complex hydraulic and reactive behavior of NBSs substrates, which should be properly combined with modeling to better understand and design NBS systems for pollutant treatment.

How to cite: Presta, L., Brunetti, G., Stumpp, C., Turco, M., and Piro, P.: Disentangling nitrogen turnover in Nature Based Solutions: hydrodynamic properties and reactive behavior , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10423, https://doi.org/10.5194/egusphere-egu24-10423, 2024.

EGU24-12231 | ECS | Posters on site | HS8.1.1

An Experimental Technique for Measuring Spatiotemporal pH and Carbon Concentration During Density-Driven Convection of CO2 in Water 

Yao Xu, Marcel Moura, Hilmar Yngvi Birgisson, and Knut Jørgen Måløy

Density-driven convection of CO2 in water will trigger the spatiotemporal evolution of pH and carbon concentration, impacting the understanding of CO2 dissolution and implementations of geological carbon sequestration. Building upon the conventional methodology which applies a single pH indicator and Schlieren imaging analysis, the enhanced experimental technique, offering a holistic view of CO2 convection within water, resulted in an accurate and visual representation of the CO2 plume propagation and a wider range of pH alteration and carbon concentration during CO2-water interactions. In response to the broad pH variations with continuous CO2 dissolution, this study utilized three pH indicators combined with the novel image analysis method to correlate the solutions’ colors to their pH. Afterwards, the carbon concentration is derived from the pH values by employing the pseudo-equilibrium theories. Leveraging an experimental technique and analytical tools to measure the spatiotemporal pH and carbon concentration, the research aims to deepen the understanding of CO2 convection behaviors, paving the way for enhanced insights into carbon sequestration and related environmental processes.

Keywords: Carbon sequestration, CO2 convection, density-driven, pH, carbon concentration

How to cite: Xu, Y., Moura, M., Birgisson, H. Y., and Måløy, K. J.: An Experimental Technique for Measuring Spatiotemporal pH and Carbon Concentration During Density-Driven Convection of CO2 in Water, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12231, https://doi.org/10.5194/egusphere-egu24-12231, 2024.

Water flow in the vadose zone is strongly non-linear due to the feedback of water flow, saturation, and the associated hydraulic conductivity. Therefore, the simulation of unsaturated flow at the continuum scale is notoriously complicated. Yet, not only the solution of the non-linear partial differential equation itself is difficult, also the appropriate parameterization of the unsaturated hydraulic conductivity function poses a challenge. Frequently, hydraulic conductivity is estimated from the water retention curve using capillary bundle models such as the well-established Mualem model or from pedotransfer functions that hardly include information on the actual pore space morphology. Here, a novel approach is presented to estimate the full unsaturated hydraulic conductivity function from a morphological analysis of Xray-CT images in the following way. First, the local pore space morphology is evaluated to obtain pore radius, Euclidean distances to the pore wall, and connectivity measures. Then, a local hydraulic conductivity and capillary forces are calculated for individual voxels of the images. This already permits to estimate the water retention curve and the water distribution inside the pore space at different levels of saturation. These configurations are then used to calculate an associated continuum scale hydraulic conductivity from dry to fully saturated conditions. This approach can be implemented in image analysis software, e.g. ImageJ, in a straight-forward way and may provide much better and specific estimates of the unsaturated hydraulic conductivity that sensitively affects the simulation of fluid flow in soils and the vadose zone provided satisfactory pore space acquisition with Xray-CT is possible.

How to cite: Ritschel, T.: Estimation of unsaturated hydraulic conductivity from morphological analysis of Xray-CT images, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14615, https://doi.org/10.5194/egusphere-egu24-14615, 2024.

EGU24-14907 | ECS | Orals | HS8.1.1

Mixing-induced reactive transport experiments in heterogeneous and variably saturated porous media 

Oshri Borgman, Francesco Gomez, Tanguy Le Borgne, and Yves Méheust

Mixing-induced reactions are an essential feature of environmental flow and transport processes. They control many reactive transport processes, including mineral precipitation rates and contaminant remediation processes. Natural porous media are characterized by a strong structural heterogeneity, which impacts solute mixing and, therefore, the resulting chemical reaction rates. Establishing a quantitative link between pore-scale heterogeneity and mixing/reaction rates in saturated and unsaturated conditions remains an open question. Here, we study pore-scale solute mixing using high-resolution experimental measurements to quantify the overall reaction rates and product concentrations. Our goals are to study the impact of structural heterogeneity on 1) reaction rates and products during saturated flow and 2) the spatial arrangement of fluid phases during unsaturated flow and its impact on reaction rates and products.

We use two-dimensional porous media consisting of circular posts in a Hele-Shaw-type flow cell. We control heterogeneity by varying the posts’ diameters disorder and correlation length; increasing this length introduces more structure in the porous medium. We utilize an irreversible oxidation reaction to produce fluorescein from its non-fluorescent form. The Damköhler number is sufficiently larger than unity, so the reaction rate is mixing-controlled. We inject a non-fluorescent tracer pulse into the porous medium sample filled with the oxidating reactant under saturated and unsaturated flow conditions. We analyze periodic fluorescence intensity images to track the evolving solute concentration field. The reaction rates and the total reaction product mass are calculated directly from the concentration images.

Solute concentration images show that increasing the spatial correlation length under saturated flow conditions leads to enhanced reaction front stretching and elongation as the solute travels along preferential pathways. Due to this overall stretching, the reaction front is locally more compressed perpendicular to the elongation direction. In a non-correlated, randomly disordered porous medium, overall stretching is reduced, and the front is less compressed locally. Under unsaturated flow conditions, a main preferential flow path characterizes the correlated porous medium. In contrast, the non-correlated medium is characterized by a higher degree of branching and splitting in the velocity field. Solute pulse focusing in the correlated porous medium sample reduces reaction front stretching compared to the non-correlated porous medium, under unsaturated conditions. Under these conditions, the reaction rate increases more than the saturated case due to the unsaturated flow pattern's enhanced reaction front stretching. This effect is more pronounced for the non-correlated sample, where flow path splitting and reaction front stretching are more significant. This work shows that structural heterogeneity has a considerable effect on reactive solute transport and that this effect depends on the system’s saturation.

How to cite: Borgman, O., Gomez, F., Le Borgne, T., and Méheust, Y.: Mixing-induced reactive transport experiments in heterogeneous and variably saturated porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14907, https://doi.org/10.5194/egusphere-egu24-14907, 2024.

EGU24-15195 | ECS | Posters on site | HS8.1.1

Effect of water content on transport of water tracer and strontium in compacted clay-rich soil column 

Jean Maillet, Emilie Thory, Christelle Latrille, and Sébastien Savoye

Mechanisms involved in the radionuclide mobility in water-saturated environments have been extensively studied in order to predict their migration. However, in natural environments, a partially water-saturated zone occurs between the soil surface and the water table. It is well known that a decrease in water content reduces the porosity available for flow. Various studies have reported a increase or reduction of the contaminants residence time in porous media, explained by the flow paths complexity increase, a preferential path by the macroporosity and a reduced accessibility to reactive sites [1]. This study aims to understand the influence of water content on transport parameters such as dispersivity, porosity and chemical reactivity. This study investigates the effect of water content by comparing column transport experiments performed with inert (enriched-HDO water) and reactive (strontium) tracers on water-saturated and partially saturated soil.

Transport experiments were carried out on columns filled with the 300-400 µm fraction extracted by dry sieving from a sedimentary alluvium. This material was then compacted inside a glass column to reach the same density as that measured in the field (1.47 g.cm-3). Transport experiments were performed under water saturated and partially saturated conditions corresponding to 0.43 to 0.19 water content, with a CaCl2 solution equilibrated with calcite at pCO2 atm. At steady flow, tracers were introduced into the system by an injecting loop, passed through the material and was collected in sequenced fractions. Sensors placed at both inlet and outlet of the column [2] allowed pH and electrical conductivity to be continuously controlled. HDO and Sr were measured with a deuterium analyser and an ICP MS respectively. HDO and Sr breakthrough curves were interpreted with HYDRUS-1D coupled with PhreeqC softwares. A multi-site ion exchange model was implemented in PhreeqC [2]. Flowrate and porosity were experimentally measured while dispersivity was determined by inverse modelling. To compare the different experiments, results were expressed in dimensionless units: relative concentration (C/C0) and pore volume passed through the column normalized to the column pore volume (V/Vpore).

Based on experiments carried out in water-saturated media with HDO, the dispersivity in the material was estimated at 0.1 cm-1. The Sr residence time was tenfold more than HDO (from 2.5 to 30 V/Vpore), which confirms that chemical retention drives the cation migration into porous media. Three HDO experiments carried out at various water contents (0.24 to 0.19 cm.cm-1) revealed a regular dispersivity increase with decreasing water content from 0.1 to 0.2 cm-1. For Sr experiments, decreasing water content led to the increase of the breakthrough curve intensities and a tailing effect, meaning that Sr would be less retained and more spread with reduced water content.

These results show that reducing the water content in porous media leads to reduce the porosity accessibility to flow and to increase the dispersivity. This suggests that the water content decrease constrains the water flow path, this is intensified with the desaturation. The Sr transport behaviour change with desaturation may be explained by the reduction in the accessibility to the sorption sites.

 

How to cite: Maillet, J., Thory, E., Latrille, C., and Savoye, S.: Effect of water content on transport of water tracer and strontium in compacted clay-rich soil column, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15195, https://doi.org/10.5194/egusphere-egu24-15195, 2024.

EGU24-18085 | ECS | Orals | HS8.1.1

Impact of helicity on mixing in heterogeneous porous media 

Konstantinos Feroukas, Marco Dentz, Juan Hidalgo, and Daniel Lester

Mixing is the process that homogenizes initially segregated miscible constituents, increases the volume occupied by a solute, and decreases concentration peaks. It is important for the assessment of contamination levels and biogeochemical reactions in groundwater and soils. Mixing processes are governed by the interplay of fluid advection, molecular diffusion and local-scale dispersion at Darcy scale. Here we study the mechanisms of mixing in three-dimensional Darcy scale porous media with different heterogeneity structure. We analyze the role of medium and flow topology on the mixing and dispersion behavior. To this end, we perform Darcy-scale numerical simulations of incompressible flow and transport in heterogeneous three-dimensional porous media. Hydraulic conductivity is represented as a multi-Gaussian random field with lognormal marginal distribution. We consider isotropic and anisotropic correlation structures and scalar and tensorial conductivity. Flow is solved using a finite volume two-point method and transport using a Lagrangian approach. The flow topology is quantified by the helicity of the velocity field. We consider a planar injection of particles. Dispersion is quantified by the longitudinal and transverse dispersion coefficient, which are determined by the evolution along time of the position’s variance in the respective direction divide by two. It is also quantified by the breakthrough curves, which measure the distribution of arrival times at a given position from the initial one. Mixing is quantified by the ability of the flow to stretch and elongate a fluid strip which enhances diffusion through the creation and sustaining of concentration gradients. Results show that for a helical flow, a finite transverse dispersion coefficient is observed at long times and that the elongation of elemental strips follow an exponential stretching  (for large logK variances). On the contrary, on non-helical flows, transverse dispersion tends asymptotically to zero and the stretching rate is algebraic. The longitudinal dispersion coefficient seems unaffected by the helicity of the flow. These results shed light on the relation between medium structure and flow topology on mixing, making an important step towards the control, upscaling and large scale representation of mixing in porous media

.

 

How to cite: Feroukas, K., Dentz, M., Hidalgo, J., and Lester, D.: Impact of helicity on mixing in heterogeneous porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18085, https://doi.org/10.5194/egusphere-egu24-18085, 2024.

EGU24-18902 | Posters on site | HS8.1.1

Development of a new computer tool for coupling HYDRUS-1D and MODFLOW 

Bartosz Balis, Mateusz Pawlowicz, Adam Szymkiewicz, Jirka Simunek, Anna Gumula-Kawecka, and Beata Jaworska-Szulc

Groundwater management relies increasingly on numerical models to assess past, present, and future conditions, optimize strategies, and protect resources from climate and land use changes. Groundwater systems encompass the unsaturated (vadose) and saturated (groundwater) zones, with vadose zone modeling presenting computational challenges due to nonlinear equations and complex parameters. One possible solution to include the vadose zone processes in groundwater models in a flexible manner is to couple computer programs modeling 3D flow in the saturated zone with programs modeling 1D flow in the vadose zone. 

 

In this study, we introduce the HYDRUS-MODFLOW Synergy Engine (HMSE), a novel coupling approach for HYDRUS-1D and MODFLOW-2005, aimed at enhancing groundwater modeling. HMSE employs external coupling via a versatile interface, offering three deployment options: a desktop application, a Docker container, and a Kubernetes cluster. Users interact through a web interface, enabling project setup, model uploads, configuration adjustments, simulations, and result retrieval.

 

The MODFLOW's area is divided into recharge zones, each assigned a HYDRUS-1D model representing soil profiles, land cover, groundwater depth, and weather conditions. HMSE offers two coupling modes. In the simple mode, groundwater table positions are assumed constant, HYDRUS-1D simulations are performed for the entire period, and average recharge rates are calculated for MODFLOW. In the second coupling mode, MODFLOW and HYDRUS-1D interact iteratively to update the water table position in HYDRUS-1D profiles after each stress period in the MODFLOW simulation. This involves splitting the MODFLOW model into segments corresponding to different stress periods, performing HYDRUS-1D simulations, passing recharge data to the RCH file, running a MODFLOW simulation for each stress period, and using MODFLOW results to calculate the average water table depth for each recharge zone, thus updating the corresponding HYDRUS profiles while avoiding oscillations in recharge flux. 

 

HMSE combines the strengths of mature and validated HYDRUS-1D and MODFLOW-2005 programs, offering a more comprehensive understanding of groundwater systems. Our study presents a preliminary validation of HMSE for a shallow aquifer in northern Poland. We also evaluated HMSE performance in the three deployments (desktop, Docker and Kubernetes). 

How to cite: Balis, B., Pawlowicz, M., Szymkiewicz, A., Simunek, J., Gumula-Kawecka, A., and Jaworska-Szulc, B.: Development of a new computer tool for coupling HYDRUS-1D and MODFLOW, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18902, https://doi.org/10.5194/egusphere-egu24-18902, 2024.

EGU24-19360 | Posters virtual | HS8.1.1

Effect of supercritical CO2/water interactions on geomechanical behavior of quartz-rich sandstone for CO2 geological storage 

Takashi Fujii, Masashige Shiga, Yasuki Oikawa, and Xinglin Lei

In the course of CO2 injection into a storage reservoir, understanding of a volumetric change (e.g., swelling), induced by interacting among CO2, water and rock into pores of rocks should be a critical step for modeling of hydro-mechanical response relevant to CO2 capture and storage (CCS) technology. For the majority of ongoing and planning CCS sites in the globe, hard sedimentary rocks, which is main component of quartz and feldspars with less clay minerals (e.g., smectite, illite), is a representative reservoir rock. It is well-known that caprocks (i.e., mudstone and shale) occur the swelling behavior of a rock matrix in the presence of water and/or CO2 due to intercalation and exchange reactions between layers of clay minerals. However, such volumetric change effect for quartz-rich rocks is not yet being investigated enough. In this study, we investigate geomechanical behavior of quartz-rich sandstone (Berea sandstone) in supercritical CO2 (scCO2)-water system under effective pressure of 10 MPa for up to approximately 1 week, the condition of which assumes that CO2 is injected into a storage reservoir at 1 km depth. Our results demonstrated that quartz-rich sandstone had a significant potential for changes in geomechanical properties (i.e., axial stress, displacement, volumetric strain) in scCO2-water system, like that do clay-rich caprocks, although little the change being observed for only water-saturation under the same effective stresses, and its maximum value was approximately 0.3 % for scCO2/water system. Also, increasing axial stress induced by the change in volumetric strain of the rock sample tested were more than 1 MPa for all experimental runs. A comparison results suggested that the obtained volumetric strains for this system could not be explained fully by change in bulk modulus before and after introducing scCO2 into the rock sample. The findings of our study might provide a significant contribution for the coupled hydro-mechanical behavior in storing CO2 into hard sedimentary rocks.

How to cite: Fujii, T., Shiga, M., Oikawa, Y., and Lei, X.: Effect of supercritical CO2/water interactions on geomechanical behavior of quartz-rich sandstone for CO2 geological storage, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19360, https://doi.org/10.5194/egusphere-egu24-19360, 2024.

EGU24-19678 | Orals | HS8.1.1

A Spatially Distributed Leaching Model to assess pesticide leaching for exposure assessment at the European level 

Maarten Braakhekke, Pavan Cornelissen, Louise Wipfler, Aaldrik Tiktak, Anton Poot, Bernhard Jene, Gerco Hoogeweg, Abdul Ghafoor, Judith Klein, Michael Stemmer, Amy Ritter, Robin Sur, Gregor Spickermann, Gerard Heuvelink, Gregory Hughes, Stephan Marahrens, Stefan Reichenberger, Nicoleta Suciu, and Michelle Morris

Assessment of the leaching potential of pesticides and their metabolites is an important part of the authorization procedure for pesticides in Europe. To protect groundwater quality, it must be demonstrated that concentrations of active substances in the upper groundwater do not exceed 0.1 μg/L before a pesticide can be approved for use. For the purpose of exposure assessment, this concentration limit is imposed on the water leaching downward at 1 m depth in the soil profile. For a given substance and application pattern, this leaching concentration can vary in space by several orders of magnitude, due to variation in site conditions, most importantly soil properties and climate. Spatially distributed leaching modelling (SDLM) is a methodology for exposure assessment over large spatial extents, dealing with this spatial variability in a comprehensive way. It involves performing simulations for many parametrizations representative for a spatial region and can be used to generate maps or calculate spatio-temporal percentiles of leaching concentrations. While such tools are already used in exposure assessment at national level in several EU member states, no generally accepted SDLM tool is available at the European level. In 2020, a working group of Society of Environmental Toxicology and Chemistry (SETAC) was formed with the purpose to develop a harmonized framework for SDLM across Europe (EU27 + UK).

A first version of an SDLM—referred to as GeoPEARL-EU—was built around the pesticide leaching model PEARL, a field-scale model of pesticide fate in the soil-plant system. PEARL mechanistically simulates pesticide behaviour in a 1D soil column based on explicit descriptions of transport in the liquid and gas phases, sorption to the solid phase, degradation, volatilisation, and plant-uptake. Soil moisture content and fluxes are provided by the SWAP hydrological model. PEARL is used in regulatory exposure assessment for groundwater and soil. Furthermore, a spatially distributed tool based on PEARL (GeoPEARL) is used for exposure assessment in the Netherlands.

To apply PEARL to Europe, pan-European gridded datasets were collected for several variables, including soil texture, pH, soil organic carbon, weather, irrigation patterns and crop area. These datasets were used to develop a set of parametrizations covering the variability of climate and soil conditions in Europe. To this end, all 1x1 km grid cells for the EU27 + UK were partitioned into approximately 10,000 clusters using k-means clustering, based on several soil- and climate-related variables relevant for leaching vulnerability. Subsequently, a representative grid cell was selected for each cluster, which was used to obtain the data required to parameterize PEARL from the spatial data sets. Pedotransfer functions were used to derive soil hydraulic parameters.

We will present results from GeoPEARL-EU for several test cases with specific attention to the effect of the spatial aggregation approach on the model predictions. Moreover, we discuss how the tool could be used in the tiered approach of the regulatory exposure assessment for groundwater in the EU.

How to cite: Braakhekke, M., Cornelissen, P., Wipfler, L., Tiktak, A., Poot, A., Jene, B., Hoogeweg, G., Ghafoor, A., Klein, J., Stemmer, M., Ritter, A., Sur, R., Spickermann, G., Heuvelink, G., Hughes, G., Marahrens, S., Reichenberger, S., Suciu, N., and Morris, M.: A Spatially Distributed Leaching Model to assess pesticide leaching for exposure assessment at the European level, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19678, https://doi.org/10.5194/egusphere-egu24-19678, 2024.

EGU24-20806 | Orals | HS8.1.1

Pore-scale investigations of interactions between microorganisms and ionic strength: Implications for salt crystallization damage in porous media 

Jafar Qajar, Alejandra Reyes Amezaga, Selen Ezgi Celik Selen Ezgi Celik, Sebastiaan Godts, Laurenz Schröer, Amir Raoof Amir Raoof, and Veerle Cnudde

Drying of building materials filled with salt-containing moisture is a common example of salt weathering [1]. Fluid flow, such as capillary uptake of water, and local climate changes stand out as key factors in salt weathering, substantially impacting the Earth's landscape and building infrastructure [2]. While microbial organisms are known to alter rock surfaces, some exhibit physiological capabilities that beneficially impact rock properties by producing biofilms, biocement and biogas [3]. Environmental factors such as temperature, relative humidity, and ionic strength of the medium influence microbial-induced products [4]. The impact of salt type, concentration, and ionic strength on microbially mediated reactions inside porous media is a largely unexplored phenomenon at the pore scale. Effective addressing of the respective challenges requires understanding the synergistic and counter effects of bacterial interactions and salt crystallization within the internal pore structure of rocks, influencing related pore-scale processes. In this study, we explored the response to the drying process in a range of porous materials, from PDMS transparent micromodels to sedimentary porous rocks containing brine solutions of various compositions in the presence and without bacterial solutions. We used Paracoccus denitrificans bacteria in our experiments. We specifically consider the case where air with different levels of humidity and at a constant temperature is exposed to one side of the porous media, forming a drying front—a defined interface separating liquid-saturated and partially gas-filled domains. High-resolution optical and confocal microscopy, Raman spectroscopy, and X-ray micro-computed tomography (µ-CT) were used to visualize and characterize bacteria-salt aggregates interactions in the porous media. Systematic investigations were carried out to understand how the interactions between salt crystallization and bacterial reactions depend on pore space morphology, type, and ionic strength of salt solutions. The findings highlight the potential of advanced 2D and 3D imaging techniques for enhanced understanding of the transport-crystallization coupling with bacterial activity through in-situ experiments and, hence, for constructing more accurate prediction models and conservation strategies.

Keywords: Salt weathering; Bacteria; Ionic strength; Relative humidity; Evaporation; Imaging techniques.

Acknowledgement: This project has received funding from the Dutch Research Council (NWO) through the BugControl project (project number VI.C.202.074) of the NWO Talent program and from the EU INFRAIA project (H2020) the EXCITE Network.

References

[1]       Sghaier, N., S. Geoffroy, M. Prat, H. Eloukabi, and S. Ben Nasrallah, Evaporation-driven growth of large crystallized salt structures in a porous medium. Physical Review E, 2014. 90(4): p. 042402.

[2]       Grossi, C.M., P. Brimblecombe, B. Menéndez, D. Benavente, I. Harris, and M. Déqué, Climatology of salt transitions and implications for stone weathering. Science of The Total Environment, 2011. 409(13): p. 2577-2585.

[3]       Llop, E., I. Alvaro, A. Gómez-Bolea, M. Hernández Mariné, and S. Sammut, Biological crusts contribute to the protection of NeolithicHeritage in the Mediterranean region, in Science and Technology for the Conservation of Cultural Heritage. 2013. p. 33-36.

[4]       Ferrer, M.R., J. Quevedo-Sarmiento, M.A. Rivadeneyra, V. Bejar, R. Delgado, and A. Ramos-Cormenzana, Calcium carbonate precipitation by two groups of moderately halophilic microorganisms at different temperatures and salt concentrations. Current Microbiology, 1988. 17(4): p. 221-227.

How to cite: Qajar, J., Reyes Amezaga, A., Selen Ezgi Celik, S. E. C., Godts, S., Schröer, L., Amir Raoof, A. R., and Cnudde, V.: Pore-scale investigations of interactions between microorganisms and ionic strength: Implications for salt crystallization damage in porous media, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20806, https://doi.org/10.5194/egusphere-egu24-20806, 2024.

EGU24-20962 | ECS | Posters on site | HS8.1.1

Preventing Salt Precipitation in Soils through Density-Driven Salt Instabilities 

Stefanie Kiemle, Theresa Schollenberger, Katharina Heck, Rainer Helmig, Carina Bringedal, and Hans van Duijn

Soil salinization causes severe problems in agriculture, especially in arid and semi-arid regions, as it leads to soil degradation and reduces plant growth. During evaporation from a saline-water-saturated soil, salt accumulates near the top of the soil. Depending on the conditions, the increasing salt concentration will either lead to precipitation once the solubility limit is reached or due to the increase in the liquid density a gravitationally unstable situation is given, where instabilities in the form of fingers will develop. Hence, salt can be transported downwards. The development of these instabilities and the potential salt precipitation have been analyzed using numerical simulations on the REV-scale. The simulations were performed by using the numerical simulator DuMuX.  

We analyzed the relevant processes to identify the influence of different parameters like soil-hydraulic properties, evaporation rate, or salt properties on precipitation. In Bringedal et. al., 2022, the appearance of instabilities during evaporation from a one-phase system was investigated using a linear stability analysis and numerical simulations on the REV-scale. The linear stability set criteria for the onset of instabilities for a large range of parameters, whereas the numerical simulations provide information about the development of the instabilities after onset. By combining both methods, we can predict the occurrence of instabilities and their effect on the salt concentration near the top boundary. This analysis has been extended to two-phase systems to analyze the impact of phase saturation on the development of salt instabilities. 

In future work,  we plan to improve the REV-scale models with the help of the pore-network model. This will be done by identifying relevant parameters for salinization processes on the pore scale and using suitable upscaling methods for the use on the REV-scale.

How to cite: Kiemle, S., Schollenberger, T., Heck, K., Helmig, R., Bringedal, C., and van Duijn, H.: Preventing Salt Precipitation in Soils through Density-Driven Salt Instabilities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20962, https://doi.org/10.5194/egusphere-egu24-20962, 2024.

EGU24-21133 | Posters on site | HS8.1.1

Implementation of the Brunswick model system into the Hydrus software suite 

Jiri Simunek, Efstathios Diamantopoulos, and Tobias K. D. Weber

The modular framework for modelling unsaturated soil hydraulic properties over the full moisture range of Weber et al. (2019) and Streck and Weber (2020) was implemented in the Hydrus Suite. Users can now additionally choose between four different variants of the Brunswick model: i) van Genuchten-Mualem (van Genuchten, 1980; Mualem, 1976), ii) Brooks-Corey (Brooks and Corey, 1964), iii) Kosugi (Kosugi, 1996), and iv) modified van Genuchten (Vogel and Cislerova, 1988). For demonstration purposes, simulation results of bare soil evaporation and root water uptake with Hydrus are presented, along with a comparison of the original van Genuchten-Mualem model and its Brunswick variant. Results show that the original van Genuchten-Mualem model underestimates the simulated cumulative evaporation and cumulative transpiration due to the inconsistent representation of the soil hydraulic properties in the dry moisture range. We also implemented a two-step hydro-ptf into the Hydrus Suite that converts the parameters of the original van Genuchten-Mualem model to the Brunswick variant (Weber et al., 2020). In that way, physically comprehensive simulations are ensured in case no data on soil hydraulic properties are directly available, but information on physical soil properties (e.q., texture, bulk density) exists.

How to cite: Simunek, J., Diamantopoulos, E., and K. D. Weber, T.: Implementation of the Brunswick model system into the Hydrus software suite, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21133, https://doi.org/10.5194/egusphere-egu24-21133, 2024.

EGU24-21207 | Posters on site | HS8.1.1

 Dissecting the spatio-temporal variability of soil hydraulic properties in an agricultural eroded area 

Giuseppe Brunetti, Radka Kodešová, Miroslav Fér, Antonín Nikodem, Aleš Klement, and Jiří Šimůnek

The combined effect of anthropogenic and climatic stressors deeply influences the hydrological behavior of agricultural areas, especially on hillslopes. Tillage induces an abrupt change in the soil's hydraulic functioning, which can be dynamically recovered in time due to natural consolidation, alternation of wetting and drying cycles, and other biophysical factors. Heavy rainfall can accelerate the recovery process, but also induce erosion events in tilled soils, further exacerbating the spatial variability of the topsoil hydraulic properties. To better understand the mechanisms driving the spatio-temporal variability of soil hydraulic properties in agricultural areas, we combine the modified hydrological model HYDRUS with transient soil moisture observations from two hillslopes in the Czech Republic exposed to tillage and erosion. In particular, the Bayesian inference is used to calibrate two alternative HYDRUS implementations at five different locations along the hillslopes. The first model assumes static soil hydraulic properties, while the second simulates their dynamic change induced by tillage and natural consolidation (due to rainfall). The Watanabe-Akaike Information Criterion (WAIC) is used to compare the two models by considering not only the fitting accuracy, but also the predictive uncertainty. The results show that both models can reproduce soil moisture observations satisfactorily at different depths and locations. While the dynamic model exhibits slightly better fitting, this is compensated by larger predictive uncertainty compared to the static model. This is confirmed by the WAIC values, which are similar for the two models. An in-depth analysis indicates that the dynamic recovery of soil hydraulic properties happens during the first few rainfall events (confirming what was observed in other studies) and suggests that higher resolution measurements are needed to better estimate recovery factors. Finally, the spatial variability of the estimated soil hydraulic parameters hints at a possible role of overland flow fluxes along the hillslope as a heterogeneity-generating factor. 

How to cite: Brunetti, G., Kodešová, R., Fér, M., Nikodem, A., Klement, A., and Šimůnek, J.:  Dissecting the spatio-temporal variability of soil hydraulic properties in an agricultural eroded area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21207, https://doi.org/10.5194/egusphere-egu24-21207, 2024.

Delineation of Subsurface Tectonic Structures Using Gravity, Magnetic and Geological Data in the Sarir-Hameimat Arm of the Sirt Basin, NE Libya

By

Mohamed Saleem1 and Hana Ellafi2

1 &2 Petroleum Research Center

 

 

ABSTRACT

The study area is located in the eastern part of the Sirt Basin, in the Sarir-Hameimat arm of the basin, south of Amal High. The area covers the northern part of the Hamemat Trough and the Rakb High. All of these tectonic elements are part of the major and common tectonics that were created when the old Sirt Arch collapsed, and most of them are trending NW-SE. This study has been conducted to investigate the subsurface structures and the sedimentology characterization of the area and attempt to define its development tectonically and stratigraphically.

About 7600 land gravity measurements, 22500 gridded magnetic data, and petrographic core data from some wells were used to investigate the subsurface structural features both vertically and laterally. A third-order separation of the regional trends from the original Bouguer gravity data has been chosen. The residual gravity map reveals a significant number of high anomalies distributed in the area, separated by a group of thick sediment centers. The reduction to the pole magnetic map also shows nearly the same major trends and anomalies in the area. Applying the further interpretation filters reveals that these high anomalies are sourced from different depth levels; some are deep-rooted, and others are intruded igneous bodies within the sediment layers. The petrographic sedimentology study for some wells in the area confirmed the presence of these igneous bodies and defined their composition as most likely to be gabbro hosted by marine shale layers. Depth investigation of these anomalies by the average depth spectrum shows that the average basement depth is about 7.7 km, while the top of the intrusions is about 2.65 km, and some near-surface magnetic sources are about 1.86 km. The depth values of the magnetic anomalies and their location were estimated specifically using the 3D Euler deconvolution technique. The obtained results suggest that the maximum depth of the sources is about 4938m.

The total horizontal gradient of the magnetic data shows that the trends are mostly extending NW-SE, others are NE-SW, and a third group has an N-S extension. This variety in trend direction shows that the area experienced different tectonic regimes throughout its geological history.

How to cite: Saleem, M. and Ellafi, H. and the Mohamed Saleem: Delineation of Subsurface Tectonic Structures Using Gravity, Magnetic and Geological Data, in the Sarir-Hameimat Arm of the Sirt Basin, NE Libya, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2060, https://doi.org/10.5194/egusphere-egu24-2060, 2024.

EGU24-2767 | Posters on site | EMRP2.2

Origins of the high-amplitude magnetic anomaly zone in the northern South China Sea continental margin 

Wen-Bin Doo, Yin-Sheng Huang, and Hsueh-Fen Wang

Similar to the feature in the U.S. East Coast, an obvious roughly NE-SW trending high-amplitude magnetic belt (NSCSMA) appears in the northern South China Sea (SCS) continental margin, which extends from southwest Taiwan to the area about 114.5°E and 20°N. The likely cause of this magnetic high is important and interesting but still controversial. This study uses wavelet spectrum analysis, 2-D magnetic modeling, and compact inversion to constrain its causative sources. Our analysis results show the evidence indicating that the geometry and depth of the causative magnetic sources were varied along the strike of the NSCSMA (~15 km in the east and ~25 km in the west). Based on our findings and previous studies, we proposed that the major causative source of the NSCSMA could be the serpentinized upper mantle material.

How to cite: Doo, W.-B., Huang, Y.-S., and Wang, H.-F.: Origins of the high-amplitude magnetic anomaly zone in the northern South China Sea continental margin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2767, https://doi.org/10.5194/egusphere-egu24-2767, 2024.

EGU24-4792 | Orals | EMRP2.2

Comparison and understanding of sparse magnetization vector inversion 

Yang Ou, Jie Zhang, Dingyu Jia, Yang Li, and Yi Yang

Magnetization vector inversion (MVI) is an effective method for interpreting magnetic data without knowing the magnetization directions. Nevertheless, the serious nonuniqueness problem makes it difficult to obtain satisfactory results without proper constraints. Several constrained methods have been applied to the magnetization vector inversion to produce reliable results. To better understand these issues and provide some improvements, we compared and evaluated different forms of magnetization vector inversion: (1) magnetization vector inversion in Cartesian coordinates (MVI-C); (2) magnetization vector inversion in spherical coordinates (MVI-S); and (3) compact magnetization vector inversion with magnitude constraints. Magnetization vector inversion incorporates prior information or assumptions about subsurface geological structures into the model objective function and solves the optimal problem with respect to the data and the model objective function to recover the desired features. We first analyze different model objective functions and then test these methods against synthetic and real datasets. Theoretical analysis and tests reveal that the linear relationship in the rectangular coordinate system simplifies the calculation process, but it is difficult to apply reasonable constraints, which results in a lack of correlation in the direction of magnetization; moreover, the distribution is not concentrated. It is easy to constrain the magnetization magnitude and direction in the spherical coordinate system, and better results can be obtained. However, due to the nonlinear relationship, the calculation complexity increases, and the inversion results are heavily dependent on the initial model. The method based on the modulus constraint establishes the relation between components in the Cartesian coordinate system, but the direction cannot be constrained. Therefore, we believe that the magnitude and direction of magnetization should be constrained simultaneously in the rectangular coordinate system to obtain a fast, stable, and accurate inversion method.

How to cite: Ou, Y., Zhang, J., Jia, D., Li, Y., and Yang, Y.: Comparison and understanding of sparse magnetization vector inversion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4792, https://doi.org/10.5194/egusphere-egu24-4792, 2024.

EGU24-5563 | ECS | Posters on site | EMRP2.2

High-resolution magnetic and gravimetric map of the South of Salamanca (Spain): tectonic insights and implications on Sn-W mineralization 

Irene DeFelipe, Alberto Santamaría Barragán, Irene Pérez-Cáceres, Puy Ayarza, Imma Palomeras, Mariano Yenes, Juan Gómez Barreiro, Raúl Prieto, Mercedes Rivero-Montero, and Yolanda Sánchez-Sánchez

Within the Iberian Peninsula and specifically in the Iberian Massif (the westernmost outcrop of the Variscan orogen in Europe), several aeromagnetic anomalies stand out, and many of them are related to late-Variscan gneiss domes. However, some of them are not fully understood because: 1) they are not clearly linked to extensional structures and/or gneiss domes, 2) they are not related with the outcropping rocks, and/or 3) the aeromagnetic map does not provide enough resolution to relate them with the local geology. For example, the Salamanca Magnetic Anomaly (SAMA), in the central-western part of Spain, is a conspicuous reverse polarity magnetic anomaly that features a maximum amplitude of 56.1 nT. However, it does not show any relationship with the magnetic properties of outcropping rocks. In this regard, preliminary studies show that the outcropping Ordovician Slates present randomly reverse polarity Natural Remanent Magnetization which is compatible with that of the SAMA but with very low intensity. Therefore, we have undertaken a large magnetic survey of this anomaly and its continuation to the south. Gravity has also been measured in an effort to constrain the source of the SAMA. The study area, which extends to the south of the city of Salamanca is affected by the Alba-Villoria NE-SW oriented Alpine fault that puts into contact Neoproterozoic and Paleozoic rocks of the Iberian Massif with Cenozoic sedimentary rocks. In addition, the Variscan Salamanca Detachment Zone, a late-Variscan extensional structure allowed deep rocks and crustal melt products to reach shallow crustal levels, probably easing Sn-W mineralization in the area. Our new Bouguer and magnetic anomaly data depict the Alba-Villoria Fault and show a straightforward correlation between gravity and magnetic maxima. Although the magnetic maxima could be the potential field response of dense and magnetic slates common in the area, the ones measured do not present high magnetic susceptibility. Accordingly, this new data might indicate that late-Variscan extension triggered the intrusion of dense and magnetic basic rocks in a process that could have contributed to Sn-W mineralization.

Acknowledgements: We thank the funding provided by the Junta de Castilla y León and Fondo Europeo de Desarrollo Regional (SA084P20), the Fundación Memoria de D. Samuel Solórzano Barruso grant (FS3-2021), Grant PID2020-117332GB-C21 (MCIN/AEI/10.13039/501100011033) and TED2021-130440B-I00 (MCIN/AEI/10.13039/501100011033) and EU NextGenerationEU/PRTR. IDF received support from the Ayuda para la recualificación de sistema universitario español 2021-2023 and MRM from the Programa Margarita Sala, Ministerio de Universidades and UCM (CT18/22).

How to cite: DeFelipe, I., Santamaría Barragán, A., Pérez-Cáceres, I., Ayarza, P., Palomeras, I., Yenes, M., Gómez Barreiro, J., Prieto, R., Rivero-Montero, M., and Sánchez-Sánchez, Y.: High-resolution magnetic and gravimetric map of the South of Salamanca (Spain): tectonic insights and implications on Sn-W mineralization, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5563, https://doi.org/10.5194/egusphere-egu24-5563, 2024.

EGU24-7682 | Orals | EMRP2.2

Potential field signature of a late-Variscan extended realm. Implications for western Iberia Sn-W mineralization 

Puy Ayarza, Mercedes Rivero Montero, Juan Gómez Barreiro, José Ramón Martínez Catalán, Pablo Calvín, Yolanda Sánchez Sánches, and Immaculada Palomeras

The internal part of the Central Iberian Arc (CIA) features a number of long-wavelength, high amplitude aeromagnetic anomalies that overlap gneiss domes developed during late Variscan extension. Some of the largest anomalies are located at the core of the CIA and coincide with the western Iberia Sn-W belt, e.g., the Porto-Veira-Guarda Magnetic Anomaly (PVGMA) and the Central System Magnetic Anomaly (CSMA). Despite both of them lying on top of the products of crustal extension and melting (granites and migmatites), outcropping rocks do not feature high magnetic susceptibilities, raising the question about the origin of the anomalies.

In the last two years, ground high-resolution magnetic and gravity surveying has been carried out in the northern part of the CSMA, in the boundary between igneous rocks and their metamorphic host rocks. The latter are part of thermal domes developed in the latest stages of Variscan extension. Results show that magnetic highs coincide with gravity highs, thus indicating that the source of the anomalies is probably basic rocks. Indeed, scarce outcropping gabbros have magnetite, and feature a moderate magnetic susceptibility, but a very high magnetic remanence (Qn<400) of reverse polarity and directions that match those of the Kiaman superchrone, compatible with the age of gabbros (305-294 Ma). Furthermore, the characteristics of the magnetic anomalies, featuring long wavelengths, indicate that magnetic rocks (gabbros) abound at depth.

The sole existence of gabbros, albeit scarce, in the study area indicates that the mantle was involved in late Variscan extension in this part of the CIA. Crustal thickening associated to the development of the CIA must have produced lithospheric instabilities that eased the entrance of mantle melts, including metals like Sn and W, nowadays highly demanded.

Acknowledgements: Projects SA084P20, TED2021-130440B-100 and PID 2020-117332GB, MS (UCM, CT18/22)

How to cite: Ayarza, P., Rivero Montero, M., Gómez Barreiro, J., Martínez Catalán, J. R., Calvín, P., Sánchez Sánches, Y., and Palomeras, I.: Potential field signature of a late-Variscan extended realm. Implications for western Iberia Sn-W mineralization, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7682, https://doi.org/10.5194/egusphere-egu24-7682, 2024.

EGU24-8386 | Posters on site | EMRP2.2

Image of the crust and upper mantle tectonic structure and associated mineral systems of the central Norwegian Caledonides from 3D inverse geoelectrical models 

Svetlana Kovacikova, Graham Hill, Sofie Gradmann, Radek Klanica, Gokhan Karcioglu, Jan Vozár, Jochen Kamm, Pankaj Mishra, Maxim Smirnov, and Oskar Rydman

The current effort to move to more renewable energy sources and away from a petroleum based energy economy, ‘Net Zero’, places a renewed need for improving identification and characterization of mineral deposits in order to provide the materials required. Recent work, has demonstrated the benefit of larger aperture investigations of mineral systems for both determining the processes responsible for their emplacement as well as identifying indicative geophysical signatures associated with metal endowment. The central Norwegian Caledonides historically represent a zone of large mineral endowment, though; the large-scale structural history and process that formed the mineralization remain enigmatic. Formation and concentration of metals into economic mineral deposits requires a combination of processes operating at different scales. With the near surface mineral deposit being a small component of the larger mineral system which encompasses deep fluid sources and metals, an energy source for driving circulation pathways for the migration of enriched fluids, a depositional mechanism responsible for the formation of the deposit and a fluid outflow. The Norwegian mineral deposits lie within the allochthonous nappes, detached from the original Precambrian Svecokarelian and Sveconorwegian basement and having undergone tens to hundreds of km of lateral transport. Regional scale geophysical modelling of petrophysical properties has the ability to characterize and identify the structure and process occurring throughout the entire mineral system  and determine indicative structures at mid-lower crustal depths indicative of economically viable near surface regions of metal endowment (i.e. the near surface mineral deposit). To determine the processes associated with formation of the Norwegian Caledonides and its associated mineral deposits a dense network of ~300 broadband magnetotelluric soundings covering the period range 10-3-103s have been collected over two field campaigns in 2022 and 2023 in the Trondelag area of central Norway. Phase tensor analysis indicates that the data set is 3D at all scales – we have modelled the MT data using a 3D approach (GoFEM) capable of incorporating the rugged topography of the survey area. Preliminary modeling results reveal lithospheric-scale structural controls associated with known near surface mineral deposits and processes related to the lateral transport from the underlying lower crustal source regions. As such, regional geophysical surveys offer both an economic and environmentally friendly approach to large-scale exploration efforts through identification of regional scale structural controls that are indicative of metal endowment.

How to cite: Kovacikova, S., Hill, G., Gradmann, S., Klanica, R., Karcioglu, G., Vozár, J., Kamm, J., Mishra, P., Smirnov, M., and Rydman, O.: Image of the crust and upper mantle tectonic structure and associated mineral systems of the central Norwegian Caledonides from 3D inverse geoelectrical models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8386, https://doi.org/10.5194/egusphere-egu24-8386, 2024.

EGU24-8633 | ECS | Posters on site | EMRP2.2

A Streamlined Neural Network Architecture for Magnetic Data Inversion 

Xiaoqing Shi, Hua Geng, and shuang Liu

Data-driven methods based on deep learning have been applied to magnetic inversion and achieved excellent results. However, the existing neural network structures used for inversion are relatively complex, resulting in increased computational costs. Different from the inversion structure of existing encoder-decoder structures, this study designed a streamlined neural network inversion architecture based on the characteristics of magnetic anomaly forward modeling. The network structure only contains a decoder that maps magnetic anomaly data to a three-dimensional magnetic susceptibility model, which can save computational costs. First, the single-channel input data is transformed into multi-channel data through a transformation, then it is transformed into the dimensions of the magnetic susceptibility model through a four-layer decoder, and then the multi-channel data is transformed into a single channel through transformation, and finally the output is 3D magnetic susceptibility model. The transformation coefficients are trained by neural network. The neural network structure designed by this method is interpretable. It can reduce the parameters that need to be trained, reduce training time, and achieve high accuracy. It was verified through simulated and measured magnetic anomaly data, and high-precision inversion results were obtained. This idea can also be generalized to the inversion of other data.

How to cite: Shi, X., Geng, H., and Liu, S.: A Streamlined Neural Network Architecture for Magnetic Data Inversion, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8633, https://doi.org/10.5194/egusphere-egu24-8633, 2024.

Gravity surveys constitute an important method for investigating the Earth’s interior based on density contrasts related to Earth material differentials. Because lithology depends on the environment and the period of formation, there are generally clear boundaries between rocks with different lithologies. Inversions with convex functions for approximating the L0 norm are used to detect boundaries in reconstructed models. Optimizations can easily be found because of the convex transformations; however, the volume of the reconstructed model depends on the weighting parameter and the density constraint rather than the model sparsity. To determine and adapt the modelling size, a novel non-convex framework for gravity inversion is proposed. The proposed optimization aims to directly reduce the L0 norm of the density matrix. An improved iterative hard thresholding algorithm is developed to linearly reduce the L0 penalty during the inner iteration. Accordingly, it is possible to determine the modelling scale during the iteration and achieve an expected scale for the reconstructed model. Both simple and complex model experiments demonstrate that the proposed method efficiently reconstructs models. In addition, granites formed during the Yanshanian and Indosinian periods in the Nanling region, China, are reconstructed according to the modelling size evaluated in agreement with the magnetotelluric profile and density statistics of rock samples. The known ores occur at the contact zones between the sedimentary rocks and the reconstructed Yanshanian granites. The ore-forming bodies, periods, and processes are identified, providing guidance for further deep resource exploration in the study area.

How to cite: Zhu, D.: Gravity inversion using L0 norm for sparse constraints, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9436, https://doi.org/10.5194/egusphere-egu24-9436, 2024.

EGU24-10535 | ECS | Orals | EMRP2.2

Can salt basins be modelled by magnetic data? A successful case study in the Eastern Mediterranean  

Luigi Bianco, Mahmoud Abbas, Luca Speranza, Bruno Garcea, and Maurizio Fedi

We discuss the analysis of magnetic data in salt basins and their potential role as a key tool in these scenarios. The study was performed on the magnetic data of a deep-water area in the offshore Egypt, Eastern Mediterranean. The reduced to pole (RTP) magnetic anomalies was computed and filtered with the discrete wavelet transform (DWT) for the regional-residual separation. The filtered anomalies were interpreted as due to the contrast between the sedimentary layers and the diamagnetic salt dome. The multiscale boundary analysis allowed the extraction of lineaments representative of the salt bodies. Moreover, the inversion of the data using a 3D non-linear non-iterative technique produced a map of the salt in the area, which was derived without constraints from seismic or other external information. from the magnetic data interpretation was performed. It needed only a local estimation of the depth to the salt in few points, as provided by Euler deconvolution of magnetic data. This result well agrees with the top of the salt interpreted from the seismic data. Our findings are not obvious and demonstrate the potential of magnetic surveys as a self-consistent and low-cost tool in the exploration of salt basins, especially when the higher resolution seismic interpretation  could suffer of possible pitfalls or seismic data are inaccessible.

How to cite: Bianco, L., Abbas, M., Speranza, L., Garcea, B., and Fedi, M.: Can salt basins be modelled by magnetic data? A successful case study in the Eastern Mediterranean , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10535, https://doi.org/10.5194/egusphere-egu24-10535, 2024.

EGU24-13204 | Posters on site | EMRP2.2

Subsurface 3D modeling of Pantelleria island (Italy) using gravity data. 

Luca Samperi, Giovanna Berrino, and Filippo Greco

Pantelleria is a 84 km2 extended volcanic island located in the Mediterranenan Sea between Sicily (Italy) and Tunisia. Previous studies described that in Pantelleria island both tectonic structures and the volcano-tectonic features had a common tectonic origin controlled by a NW-SE directed extension in accordance with the regional trend of the Sicily Channel arising interest for multiapproach investigations.

Indeed, in the last decades this area has been field of widespread analysis useful for the investigation of the volcano-tectonic and tectonic activity, as well as for geodetic study and resources exploration.

Our approach focused on the gravimetric analysis of Pantelleria island and in particular we provided a 3D inverted model of the area, starting from in-situ gravity measurements. The 250 m model resolution has been endorsed by the presence of a total of  290 measurement stations, distributed both onshore and offshore and acquired during some field surveys up to 2006; 236 of them were already published and inverted in past using 2.5D modelling. Input data consisted of a database containing Bouguer anomaly data reduced using a  density of 2500 kg/m3 and referred to the Geodetic Reference System 1980 (GRS80) Ellipsoid.

As a result, the 3D modelling allowed exploring density differences through the about 4 km depth, emphasizing interesting geological structures.

Such results would help any drilling program in the island (e.g. for geothermal purposes), lead to more successful drilling programs, and serve as well-constrained geologic input to improve the accuracy of future numerical (e.g. reservoir) models.

How to cite: Samperi, L., Berrino, G., and Greco, F.: Subsurface 3D modeling of Pantelleria island (Italy) using gravity data., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13204, https://doi.org/10.5194/egusphere-egu24-13204, 2024.

We introduce a novel estimation technique to assess the overall mass variations of the Greenland and Antarctica ice sheets. Interpreting GRACE data encounters a significant challenge due to the leakage effect resulting from the presence of outlying melting ice bodies, causing gravitational effects to interfere with each other. Our estimation employs an innovative approach that leverages the non-uniqueness of the gravity field, using a hypercompact model of the sources through an iterative inversion. Furthermore, thanks to to the extreme compactness of the sources, our method enables a more unambiguous quantification of total mass loss in the study area. We apply our method to time-varying NASA GRACE (Gravity Recovery and Climate Experiment) Stoke's coefficient data spanning from 2002 to 2017. Over a 15-year period, the GRACE and subsequent GRACE-FO missions provided a distinctive to map the Earth's gravitational field time variations. In recent years, recognizing the ice sheet's total mass response to climate change has become pivotal in comprehending phenomena such as sea level rise associated with grounded ice melting and quantifying the retreat of ice sheet fronts in polar regions, offering the scientific community a fresh perspective on unknown ice sheet dynamics.

How to cite: Maiolino, M., Fedi, M., and Florio, G.: ECS (Extremely compact sources) potential field filtering. The case of Greenland and Antarctica ice mass balance (2002-2017)., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13296, https://doi.org/10.5194/egusphere-egu24-13296, 2024.

EGU24-13361 | Posters virtual | EMRP2.2

Swarm observations of ULF wave activity and plasma instability activity around extreme geophysical events 

Georgios Balasis, Angelo De Santis, Gianfranco Cianchini, Constantinos Papadimitriou, Omiros Giannakis, and Stelios M. Potirakis

In November 2023, the ESA Swarm constellation mission celebrated 10 years in orbit, offering one of the best-ever surveys of the geomagnetic field and the topside ionosphere. Swarm provides an ideal platform for observing ultra-low frequency (ULF) waves and thus offers an excellent opportunity for space weather studies. For this purpose, a specialized time-frequency analysis (TFA) toolbox has been developed for deriving Pc1 (0.2-5 Hz) and Pc3 (20-100 MHz) wave indices, thus making it a useful tool for the study of magnetic storms. The TFA toolbox is also capable to identify in Swarm time series another category of natural-source electromagnetic signals, i.e., the post-sunset Equatorial Spread-F (ESF) events or plasma bubbles. There have been several studies suggesting that ULF pulsations may be associated with earthquakes. Previous studies refer mainly to the detection of these signals in ground-based magnetometer measurements. Besides, we note only a handful of studies that have been attempted to correlate ULF pulsations with seismic activity, using space-borne magnetometer measurements provided by Low Earth Orbit (LEO) satellites (e.g., CHAMP, DEMETER). Therefore, in this study we focus on the ULF pulsation and ESF activity observed by Swarm satellites during a time interval centered around the occurrence of the August 2016 Central Italy earthquake. Swarm has offered a variety of interesting observations around the time of this earthquake that could be associated with the occurrence of this extreme geophysical event.

How to cite: Balasis, G., De Santis, A., Cianchini, G., Papadimitriou, C., Giannakis, O., and Potirakis, S. M.: Swarm observations of ULF wave activity and plasma instability activity around extreme geophysical events, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13361, https://doi.org/10.5194/egusphere-egu24-13361, 2024.

EGU24-18236 | ECS | Posters on site | EMRP2.2

Using potential field data to investigate high-pressure sources of energy in deeply serpentinized mantle rocks 

Zeudia Pastore, Alberto Vitale Brovarone, Jérôme Gattacceca, Nathan Church, Francesco Ressico, Veronica Peverelli, Yoann Quesnel, Minoru Uehara, and Dilyara Kuzina

Serpentinization of ultramafic rocks is a key process in forming natural hydrogen. In deep settings, such as subduction zones, this process can be kinetically favored by high P-T conditions making the study of mantle rocks from these settings a compelling target for high-pressure sources of energy. Serpentinization of peridotites can lead to the formation of magnetite and it is commonly associated with a decrease in density and an increase in magnetization of the protolith rock. Gravity and magnetic methods can therefore be used to map and quantify the extent and degree of serpentinization. Here, we used a comprehensive dataset consisting of ground and Unmanned Aerial Vehicle (UAV) magnetic data, gravity data, and an extensive petrophysical data collection to explore the natural hydrogen potential in exhumed mantle rocks from the Monte Maggiore (MM) massif, in Corsica. The MM massif consists of a ∼4 km2 peridotite body, intruded by mafic pods and gabbroic dykes and surrounded by blueschist-facies continental units. It represents sub-continental mantle that underwent tectonic and magmatic evolution during the rifting stage of the Jurassic Ligurian Tethys oceanic basin and successive Alpine subduction to blueschist-facies conditions. On-going geochronological and geochemical investigations suggest that serpentinization occurred primarily in subduction making this area a suitable case study to investigate the formation of high-pressure sources of energy in such settings. We analyzed densities and magnetic properties of rocks from more than 100 sites across the massif and we used these data to identify domains exhibiting different degree of serpentinization and to model the current 3D structure of the massif using both forward and inverse modeling approaches. We estimated a minimum volume of the MM massif of 1.2 km3 and a vertical extent to a depth of 428 m below sea level. We used the modeled volumes and the amount of magnetite within each domain as a proxy for a conservative estimation of natural H2 production.

How to cite: Pastore, Z., Vitale Brovarone, A., Gattacceca, J., Church, N., Ressico, F., Peverelli, V., Quesnel, Y., Uehara, M., and Kuzina, D.: Using potential field data to investigate high-pressure sources of energy in deeply serpentinized mantle rocks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18236, https://doi.org/10.5194/egusphere-egu24-18236, 2024.

EGU24-18708 | ECS | Posters on site | EMRP2.2

A new approach of monitoring CO2 storage in deep saline aquifers from time-lapse gravity data 

Maurizio Milano and Maurizio Fedi

Here we assessed surface gravity monitoring as tool for detecting the CO2 plume in deep saline aquifers during the injection and post-injection phases. We used the available benchmark model of the Johansen reservoir to conduct the simulation of CO2 storage at about 3 km of depth for 70 years and using different injection rates. We calculated the gravity response at surface from the estimated models of reservoir density and saturation at different time intervals. The forward calculation is achieved by assuming a tetrahedral mesh discretization, such as to ensure an accurate and detailed reconstruction of the complex reservoir.

We proposed a new approach for monitoring the mass stored into the reservoir based on the DEXP method, which allows an effective reduction of interference effects from nearby sources and provide accurate results even when the anomaly is incompletely defined, due to a not proper areal coverage of the survey.

This study clearly shows that the appropriate choice of the injection rate strongly impacts on the ability to recover useful gravity signal at the surface, beyond the measurement error threshold. We also provide an in-depth analysis of the effect of noise on the mass change estimates.

Our approach could be a valid tool for conducting real time monitoring of the CO2 as it could accurately determine the effective mass stored in the reservoir. This is particularly important as it does not require information about the source and could make surface gravity surveying as an independent monitoring strategy.

How to cite: Milano, M. and Fedi, M.: A new approach of monitoring CO2 storage in deep saline aquifers from time-lapse gravity data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18708, https://doi.org/10.5194/egusphere-egu24-18708, 2024.

EGU24-19287 | ECS | Orals | EMRP2.2

A new detailed Bouguer anomaly for the exploration of the deep geothermal reservoir in SW-Belgium 

Quentin Campeol, Nicolas Dupont, Ivan Pavel Nanfo Djoufack, Louis Christiaens, Franck Martin, and Olivier Kaufmann

Located next to the Variscan front, the center of the Hainaut (SW-Belgium) is known for its deep geothermal potential. Indeed, the geothermal reservoir of the Carboniferous limestones, located in the Brabant Parautochton, currently supplies water at a temperature of between 65°C and 72°C from three deep wells in the Mons area. Although the use of geothermal energy is one of the main solutions to decrease or abandoning fossil energies, it is still very limited in this area. This situation is partly due to major uncertainties in the structure and the geometry of the reservoir which are holding back public and private investments and delay geothermal projects.

 

For these reasons, we have conducted new geophysical surveys in the center of the Hainaut region for the last fifteen years. Among these, two gravimetric surveys in relation to the More-Geo project (ERDF funding) were carried out in 2019 and in 2022. As the production levels in the geothermal reservoir of the Carboniferous limestones are karstified, replacing massive anhydrites, the study of gravimetry disturbance is appropriate. The main goal is to provide information about deep geological structures and precisely on the geothermal reservoir by refining the localisation and the extent of karstified and anhydrite levels.

 

The result of the 2019 and 2022 surveys is a new dataset of 13,000 measurements spread over 3,400 stations located in an area of 820 km². The classical Bouguer anomaly has been obtained after a full processing of the instrumental gravimetric measurements, using exclusively open-source Python libraries.

 

Special attention is given to the terrain correction which in our case is based on the modelisation of the topographic surface by rectangular prisms and on the evaluation of the gravitational influence of these prisms. The method used combines a “large-scale” terrain correction modelling the topography up to 167 km in extent with prisms of 25 m resolution and a “local” terrain correction correcting the inaccuracies of the first grid with prisms of 1 m resolution over a more limited area.

 

Results are the mapping of the Bouguer anomaly, the upward continuation, upward derivative and horizontal derivative obtained with the interpolation method of equivalent sources. The two last maps are at the base of structural interpretations of the Paleozoic basement. These results and specifically the processing will be a key to refine the localisation and the extent of deep geothermal targets within the Paleozoic basement. This will require specific processing taking into account the thick and highly heterogeneous Meso-Cenozoic cover of the Mons Basin.

How to cite: Campeol, Q., Dupont, N., Nanfo Djoufack, I. P., Christiaens, L., Martin, F., and Kaufmann, O.: A new detailed Bouguer anomaly for the exploration of the deep geothermal reservoir in SW-Belgium, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19287, https://doi.org/10.5194/egusphere-egu24-19287, 2024.

EGU24-19549 | ECS | Orals | EMRP2.2

New aeromagnetic anomaly compilations help unveil regional-scale Antarctic subglacial geothermal heat flux heterogeneity 

Jonathan Ford, Fausto Ferraccioli, Ben Mather, Egidio Armadillo, Rene Forsberg, Joerg Ebbing, Karsten Gohl, Graeme Eagles, Chris Green, Javier Fullea, and Massimo Verdoya

A new continent-wide aeromagnetic anomaly compilation for Antarctica, conformed at longer wavelengths with SWARM satellite magnetic data includes recent international datasets collected after the ADMAP 2.0 compilation analysed within the 3D Earth project of ESA.

This ADMAP 2.0+ product includes: 1) ROSETTA data collected by a US-NZ team over the Ross Ice Shelf; 2) reprocessed US-German and UK data collected over the Amundsen Sea Embayment; 3) German, Danish, UK- Argentina-Norwegian data over the Recovery ice stream catchment; 4) ESA PolarGAP data over South Pole and 5) enhanced vintage datasets for the Gamburtsev Subglacial Mountains and Wilkes and Dome C regions in East Antarctica. A new digital database was assembled using updated line data holdings and all data were levelled. microlevelled and stitched together via grid stitching approaches and subsequently differentially continued to 4 km and re-gridded on a 4 km grid mesh.

Here we use this new aeromagnetic anomaly compilation to re-assess Antarctic geothermal heat flux (GHF) heterogeneity, a critical basal boundary condition that influences Antarctic ice sheet flow and subglacial melting patterns and hydrology, and is related to crustal and lithospheric structure, composition, and heat production.

Within the 4D Antarctica ESA project we applied Curie Depth Point (CDP) estimation using the centroid, modified centroid and fractal/defractal approaches. Our new CDP map reveals regions of enhanced GHF along the coast of the Amundsen Sea Embayment, in agreement with independent seismological estimates. Potential thermal anomalies within the West Antarctic Rift System (WARS) also underlie the Byrd Subglacial Basin. Linear rift related anomalies are now imaged more clearly beneath the Siple Coast ice streams and active subglacial lake districts.

In East Antarctica, the new CDP estimates over the enigmatic WSB are significantly deeper compared even to the coldest sectors of the WARS. This suggests that if Mesozoic to Cenozoic extension affected this region, it mostly occurred at upper crustal levels rather than the whole lithosphere, in general agreement with relatively sparse seismological evidence for a predominantly cratonic lithospheric environment. A particularly intriguing region of enhanced GHF is identified in Dronning Maud Land. We propose that this could arise from lithospheric thinning perhaps associated with delamination processes, which have been independently inferred from petrological signatures in post-orogenic granitoids, emplaced after the pan-African age assembly of Gondwana. Alternatively, this feature could reflect thermal anomalies related to much later passive margin formation during Gondwana rifting and break up.

Finally, we discuss intriguing GHF anomalies inferred in the Dome C and Dome A subglacial lake regions in interior East Antarctica. We suggest the hypothesis that these anomalies relate to anomalously high intracrustal heat production, such as observed in Australia in some Proterozoic terranes, or to ill-constrained reactivation of the inherited structural architecture, This includes major Proterozoic and younger Pan-African age orogenic belts that may have been reactivated in response to far field stresses during Mesozoic to Cenozoic Gondwana break up and subsequent sea floor spreading processes.

How to cite: Ford, J., Ferraccioli, F., Mather, B., Armadillo, E., Forsberg, R., Ebbing, J., Gohl, K., Eagles, G., Green, C., Fullea, J., and Verdoya, M.: New aeromagnetic anomaly compilations help unveil regional-scale Antarctic subglacial geothermal heat flux heterogeneity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19549, https://doi.org/10.5194/egusphere-egu24-19549, 2024.

EGU24-19904 | Orals | EMRP2.2

A compact MEMS gravimeter with sub ng performance 

William T. Pike, Constantinos Charalambous, Simon Calcutt, and Ian Standley

We present the performance of a MEMS accelerometer capable of sub-migroGal Allan variance out to a period of 1000 s. The gravimeter incorporates a monocrystalline silicon suspension and capacitive sensing with electromagnetic feedback. The gravimeter is capable of operation over 10 degree tilt range under Earth gravity, allowing unsupervised operation after remote deployment with a three-axis gapleran geometry. The suspension incorporates temperature compensation to minimse the need for thermal isolation.  The overall mass of the instrument is about 0.6 kg mass,  including the packaged sensor heads, the electronics board and associated connectors and cabling with a power requirement of less than 400 mW.  The performance and resource profile make this a promising instrument for both terrestrial deployment in extreme environments as well as planetary deployment.

How to cite: Pike, W. T., Charalambous, C., Calcutt, S., and Standley, I.: A compact MEMS gravimeter with sub ng performance, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19904, https://doi.org/10.5194/egusphere-egu24-19904, 2024.

EGU24-21105 | Posters on site | EMRP2.2

Mapping a Gondwana suture zone integrating magnetic methods and geology at the SE Brazilian continental margin 

Raphaela Lopes de Andrade Silva, Renata da Silva Schmitt, Natasha Santos Gomes Stanton, and Guilherme Gonçalves Martins

According to previous reconstructions, the South Atlantic Ocean is the biggest gap of
Gondwana, with important crustal limits that controls convergent and divergent tectonic
events since the Paleoproterozoic. In the SE Brazilian continental margin, a Cambrian NE-SW
suture zone is marked by an expressive magnetic anomaly onshore that extends offshore to
the proximal Santos basin (Rio de Janeiro). This suture separates two contrasting geological
terranes: a Neoproterozoic magmatic domain (Oriental Terrane), to the west, and a
Paleoproterozoic gneissic terrane, to the east (Cabo Frio Tectonic Domain). The focus is to
determine how this suture extends offshore, hence determining the nature of the basement
that constitutes the continental margin, and how it continues in depth, determining the
orientation of the Ediacaran paleo subduction zone. We made a geological and geophysical
integration aiming to characterize the magnetic pattern of terranes and structures in order to
determinate the geometry and dip direction of the suture in depth. The methodology included
the generation and interpretation of aeromagnetic images combined with geological mapping.
Also, two magnetic sections were made on field along the suture zone and modeled on GMSYS
adopting magnetic susceptibility values obtained both on field and laboratory. The studied
area comprises mainly two geological units separated by a thrust fault (suture zone): dioritic to
granitic Paleoproterozoic rocks with metabasite layers (Região dos Lagos Complex - RLC) and
Ediacaran aluminous paragneisses with calcsilicate layers (Palmital Succession). Based on the
amplitude (intensity), geometry, magnetic signal’s texture and lineament pattern, in map view,
two domains were defined: A1 and A2. The A1 is correlated with the Paleoproterozoic
gneisses, with high amplitude, long wavelength (55 km) with numerous magnetic rectilinear
and curvilinear lineaments. Amplitude ranges between -100 and 452 nT, mostly higher than
150 nT. A2 coincides with the Palmital paragneisses, defined by a low frequency, long
wavelength (55 km) magnetic domain, with amplitudes <0 nT, resulting in a lateral contrast of
more than 500 nT with A1, where the magnetic gradient decreases to NW. Magnetic
lineaments display a preferential NE-SW direction, but in A1 a deep NW-SE fabric occurs, that
might be related with the Paleoproterozoic tectonic fabric. The suture is represented by a high
positive curvilinear lineament, extending offshore, crossing the coastline to SW before
inflecting to the east. Modeling and geological/magnetic maps correlation suggest that the
suture dips to NW. 

How to cite: de Andrade Silva, R. L., da Silva Schmitt, R., Santos Gomes Stanton, N., and Gonçalves Martins, G.: Mapping a Gondwana suture zone integrating magnetic methods and geology at the SE Brazilian continental margin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21105, https://doi.org/10.5194/egusphere-egu24-21105, 2024.

EGU24-21317 | ECS | Posters on site | EMRP2.2

Potential fields characterization of inaccessible areas: multiscale analysis of the West Antarctic Rift System 

Giuseppe Ferrara, Fauso Ferraccioli, and Maurizio Fedi

We used potential field data to help unravel the geological characteristics of the West Antarctic rift system, one of the largest and least known rift systems on our planet. A comprehensive understanding of this region is lacking, as it is covered by the West Antarctic Ice Sheet (WAIS), which reaches thicknesses of over 3 km. Aeromagnetic and aerogravity datasets collected by the British Antarctic Survey (Ferraccioli et al., 2007) were analyzed via a multiscale analysis (Fedi et al., 2015) useful for identifying the main structural lineaments, i.e., contacts, dykes, sills, volcanic bodies and intrusions in the Pine Island Glacier catchment of WAIS. Our results reveal that several regions are characterized by contact-type sources associated to fault systems bordering major magma-rich rift basins, like the Pine Island Rift, Byrd Subglacial Basin, and Bentley Subglacial Trench, as well as those associated with Pine Island glacier tributaries, which lie at high angle wrt to the glacier trunk and rift basins. Furthermore, we identified magmatic sources near or off-rift zones, such as the edges of the Bentley Subglacial Basin, which allow a better understanding of the sub-ice depth of the magmatic sources. In addition, our results provide new information about the main magmatism trends and their average depths. We thus showcase that potential field anomalies allow a better comprehension of the West Antarctic Rift System regional geology, tectonic architecture and magmatic patterns. This research opens interesting scenarios about the extent and position of magmatic sources and on how they contribute towards shaping the sub-ice topography within this sector of the rift system, which in turn is a primary control on ice sheet flow in this highly dynamic and potentially unstable sector of WAIS. In conclusion, potential field analysis with a multiscale approach emerges as a pivotal tool and provides valuable insights into continental rifting processes, especially in inaccessible areas such as West Antarctica, where there are only very few geological outcrops.

How to cite: Ferrara, G., Ferraccioli, F., and Fedi, M.: Potential fields characterization of inaccessible areas: multiscale analysis of the West Antarctic Rift System, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21317, https://doi.org/10.5194/egusphere-egu24-21317, 2024.

EGU24-22338 | ECS | Orals | EMRP2.2

Toward an optimal assessment of UAV vertical magnetic gradient arrangement 

Filippo Accomando, Giovanni Florio, Bastien Dupuy, and Madeline Lee

Among the geophysical methods, magnetic surveys are ones of the most used and reliable techniques to investigate archaeological sites. These targets are usually shallow sources generating weak amplitude anomalies. The vertical gradient measurements are preferred to the magnetic fields since it has a better sensitivity to the magnetic contributions due to shallow sources (the gradient fields decay faster than the magnetic field) and a better ability to distinguish and separate interfering anomaly due nearby sources. 
Thanks to the large deployment of UAV (Unmanned Aircraft System) of the recent years, in this work, we arranged a gradiometric system, trying one of the first attempts of vertical gradient measurements by drones for archaeological applications. These mobile platforms help to cover very large areas (this should help to follow better the long and regular shape of buried buildings) maintaining the same resolution of traditional ground surveys, with less times and risk and over sites of difficult access. However, the measurement of vertical gradients in drone-borne magnetometry is generally not taken into consideration, as it poses additional challenges to the survey and successive data processing 
In this work, we arranged the magnetic sensors as a gradiometric system, obtaining a direct estimate of the vertical magnetic gradient in a single flight. We conducted our surveys with the Geometrics Micro-Fabricated Atomic Magnetometer (MFAM).

How to cite: Accomando, F., Florio, G., Dupuy, B., and Lee, M.: Toward an optimal assessment of UAV vertical magnetic gradient arrangement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22338, https://doi.org/10.5194/egusphere-egu24-22338, 2024.

EGU24-22342 | ECS | Orals | EMRP2.2

Iterative Ratio Method: a method to map the depth to the Moho from gravity anomalies 

Dingding Wang, Wanyin Wang, and Giovanni Florio

Interfaces characterized by a density contrast are widely distributed in the Earth's interior, and their depths can be recovered by inversion of gravity data. A key parameter of the interface inversion is the density contrast. We propose to estimate a constant density contrast by a new method: the iterative-ratio method. It is based on the approximate invariance of the product between depth and a constant density contrast and on the availability of several depth constraints. The estimated density contrast is used to update the interface depth. By processing the synthetic Moho models, the inversion results show that the method is slightly affected by data noise and by the number of constraints, but it is sensitive to the constraint uncertainty. The method is finally demonstrated by mapping the Moho of the Santos basin (Brazil) according to the depth constraints and the regional gravity anomalies.

How to cite: Wang, D., Wang, W., and Florio, G.: Iterative Ratio Method: a method to map the depth to the Moho from gravity anomalies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22342, https://doi.org/10.5194/egusphere-egu24-22342, 2024.

ERE6 – Inter-and Transdisciplinary Sessions (ITS) related to ERE

Urban Green Spaces (UGS) serve as crucial ecological and social assets in urban areas, significantly contributing to the sustainability and well-being of city life. This research delves into the assessment of UGS quality in Delhi, aligning with the 2030 Agenda for Sustainable Development, specifically Sustainable Development Goal (SDG) 11 - Sustainable Cities and Communities. This study emphasizes the importance of UGS as Nature-Based Solutions. Previous studies have explored diverse attributes to evaluate UGS quality, incorporating elements like percentage green, built-up density, and proximity to green spaces. However, these studies often focused on specific aspects associated with any of the three important elements: impervious areas, vegetation, and population. This approach leaves a gap in comprehensively assessing the overall status of UGS, even if one element is taken out of the picture. To address these limitations, this study adopts a holistic approach by considering nine key attributes, including Proportional Population, Impermeable Surface Area, Proportional Impermeable Surface Area, Per-capita Green Index, Buffer Area around UGS, Normalized Difference Vegetation Index, Soil Adjusted Vegetation Index, Green Space Coverage, and Proportional Green, to offer a quantitative measure of UGS quality in Delhi. The Urban Green Spaces Assessment Index (UGSAI), derived from these attributes, provides a comprehensive understanding of UGS in the city, ranging from 0 to 100. The UGSAI categories, divided into five - Very Low (<20), Low (20-35), Moderate (35-50), High (50-65), and Very High (>65), were carefully determined for effective representation, revealing significant variations among wards. A higher UGSAI value indicates better green space conditions, signifying areas that are more accessible, sufficient to cater to the needs of the population of the particular ward, and have higher-quality green spaces. UGSAI values for the wards ranged from the lowest at 6.10 to the highest at 76.32. The study unveils that over 60% of wards fall into the Very Low to Low category, 33% in Moderate, and only 5% in the High to Very High category of UGSAI. Additionally, the correlation of the nine attributes used was tested with UGSAI, and the results indicated strong correlations between UGSAI and Green Coverage, SAVI, and NDVI (r=0.90), along with a strong negative correlation with Impermeable Surface Area (r = -0.87), revealing the attributes that are crucial for improving the UGSAI of a ward. This underscores the need for local-level improvements in management and an increase in UGS, especially in the identified critical areas. This research, grounded in Nature-Based Solutions, provides valuable insights for decision-makers, promoting informed choices that foster resilient and sustainable urban ecosystems. Moreover, the robust methodology and effectiveness of the Urban Green Spaces Assessment Index (UGSAI) presented in this study underscore its potential as a valuable tool applicable beyond Delhi, offering a comprehensive framework for assessing UGS in diverse urban contexts and guiding sustainable development initiatives.

How to cite: PANWAR, M. and Mina, U.: Nature-Based Solutions for Sustainable Cities using Urban Green Spaces Quality Assessment Index (UGSAI), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-721, https://doi.org/10.5194/egusphere-egu24-721, 2024.

The integration of Nature-Based Solutions (NBS) in urban stormwater management holds transformative potential, promising enhanced adaptive capacities and numerous benefits for community well-being. Acknowledging the localized nature of NBS projects, primarily managed at the community level, this study delves into the prospects of integrating community governance into the planning, implementation, and success of NBS initiatives, especially in the context of urban flooding.

With the overarching goal of identifying strategic leverage points for enhancing community governance structures in urban NBS implementation, the research employs a System Dynamics modeling approach, to investigate the impact of decentralizing decision-making authority to local communities on the scalability and sustainability of NBS in urban stormwater management. The analysis probes dynamic interactions and causal relationships among decentralized decision-making structures and critical variables such as community participation, institutional frameworks, and resource allocation that define community governance. Emphasizing a comprehensive understanding of feedback mechanisms, the study seeks to unravel processes shaping the adaptive capacities of NBS over time, particularly within the intricate context of adapting to the impacts of climate change.

The study strives to provide insights into the mechanisms governing scalable integration, underscoring the vital role of community involvement and participatory governance in Nature-based flood solutions and in doing so, offering a crucial foundation for fostering sustainable and resilient urban development amid the escalating challenges posed by urban flooding and climate change. 

How to cite: Muwafu, S. P. and Manez Costa, M.: Fostering Community Governance of Nature-Based Solutions for Urban Stormwater Management: A System Dynamics Analysis of Power Decentralization, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1226, https://doi.org/10.5194/egusphere-egu24-1226, 2024.

EGU24-1279 | Posters on site | ITS4.4/ERE6.4

Hybrid measures for flood risk management: combining hydrological investigation and public perception survey 

Nejc Bezak, Pavel Raška, Lenka Slavíková, Jiří Louda, and Jiří Jakubínský

Climate change is expected to affect the frequency, magnitude and seasonality of various precipitation-related hazards, including flooding as one of the costliest hazards in Europe. As natural hazards have a significant impact on infrastructure, human lives, and habitats, it is clear that adaptation measures aimed at both prevention and mitigation need to be considered to address climate change. Green (referred to as Nature-based) measures are currently being promoted by the European Union, but in some planning contexts these measures may not be fully capable of coping with predicted future climate hazards, especially in the case of extreme events. Furthermore, the implementation of such measures is often met with resistance from planning departments and decision makers due to institutional dependencies created by the use of grey infrastructure measures in the past. In addition, scepticism about the effectiveness of green measures goes hand in hand with a preference for grey measures. Hybrid measures do have a prevailing green visual look, they can fulfil some ecosystem services, but they require substantial technical equipment for implementation and may present a feasible complementary measure in planning context with limited space or already existing infrastructure. These solutions therefore combine parts of grey and green measures and present an alternative that can reflect the diversity of environmental conditions.

This study evaluated the effectiveness of selected green (e.g. urban trees, rain gardens), grey (e.g. drywells, permeable sidewalks) and hybrid (e.g. green roofs, stormwater tree tranches) measures on flood risk using hydrological modelling with the HEC-HMS software. This study was carried out in order to define the most effective and suitable flood protection measures for the selected case study, the Glinšcica river basin in the municipality of Ljubljana in Slovenia. Based on the hydrological modelling performed, rain gardens were found to be the most effective measure in terms of reducing peak runoff and runoff volume for the Glinšcica river model. Both green roofs and stormwwater cisterns also showed relatively good results compared to the other measures. The hydrological study was combined with a public perception survey in which we investigated the acceptance, feasibility and effectiveness from the perspective of the Slovenian public. Therefore, we were interested in whether there are differences in the perception of the selected green, grey and hybrid flood risk management measures. We were also interested in which of the contextual (e.g., flood exposure and experience) and compositional (e.g., socio-demographics) factors influence public perception of the acceptability, feasibility, and effectiveness of these measures.

Acknowledgment: The research was conducted within the project [Evaluation of hazard-mitigating hybrid infrastructure under climate change scenarios] co-granted by Slovenian Research Agency (J6-4628) and Czech Science Foundation (22-04520L). 

How to cite: Bezak, N., Raška, P., Slavíková, L., Louda, J., and Jakubínský, J.: Hybrid measures for flood risk management: combining hydrological investigation and public perception survey, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1279, https://doi.org/10.5194/egusphere-egu24-1279, 2024.

EGU24-1829 | ECS | Orals | ITS4.4/ERE6.4 | Highlight

Improving water-related ecosystem services to developing country communities through nature-based solutions 

Kalina Fonseca, Mercy Ilbay, Edgar Espitia-Sarmiento, and Lutz Breuer

The political, economic, social, technological, environmental, and legal (PESTEL) dimensions in a local community shape the adoption of specific nature-based solutions (NbS) to improve water ecosystem services. This study provides crucial insights on integrating NbS tailored to smallholder indigenous and peasant communities in four central Ecuadorian provinces, covering 43.2% of the Andean region. These communities are located in the páramo, a highly valued ecosystem for water-related ecosystem services. However, they face high levels of poverty and malnutrition. Combining a participatory multi-stakeholder approach with a literature review, we gathered insights into PESTEL dimensions impacting páramo ecosystem services. A bibliometric and decision tree analysis was then employed to reveal NbS aligned with PESTEL dimensions in these communities. As a result, limited financial support, urban-centric environmental investment, and insufficient acknowledgment of water-related ecosystem services significantly impact the health of páramo ecosystems from economic and political dimensions, respectively. In the environmental dimension, the overexploitation of this ecosystem, driven by high soil carbon storage combined with superior water quality and the high vulnerability to climate change, contributes to the decline of the páramo remnants. Social, legal, and technological dimensions involve community dissatisfaction and resistance to conservation, lack of sustainable land and water management, and the mismatch between technology, the economy, and data availability. These impacts on páramo ecosystem services occur directly through water purification, regulating soil formation, and maintaining populations and habitats. Indirectly, they affect the provision of water for drinking and non-drinking purposes, fishing and aquaculture, recreation, and spiritual and symbolic appreciation. To enhance water-related ecosystem services, we propose the establishment of artificial floating islands such as NbS. These islands are seen as an innovative restoration method with multiple benefits, such as the need for only limited financial support, the engagement of local communities, the lack of land requirements for implementation, and the use of indigenous community knowledge of appropriate plant species for water treatment, which can even generate additional income. Passive restoration complements this by removing disturbances in the páramo, allowing natural regeneration in basins by state-led land purchase initiatives to ensure the protection by Ecuadorian conservation laws. Our study offers decision-makers a practical approach to secure ecosystem services for vulnerable populations, critically assessing alternatives based on the dimensions and needs of these communities.

How to cite: Fonseca, K., Ilbay, M., Espitia-Sarmiento, E., and Breuer, L.: Improving water-related ecosystem services to developing country communities through nature-based solutions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1829, https://doi.org/10.5194/egusphere-egu24-1829, 2024.

The integration of Eco-DRR practices in geopark management is a promising method to strengthen community resilience. In the context of the Caota dunes geopark, the level of engagement and support from local residents could significantly contribute to the effectiveness of Eco-DRR approaches through fostering awareness, strengthening the local economy, enhancing ecosystem services, promoting sustainable resource use and facilitating the adoption of resilient livelihood practices. However, it is essential to first understand the needs of the community before implementing these strategies. This study aimed to identify critical factors by exploring community needs and challenges through interviews and focus groups to identify pathways for an inclusive and community-centered approach to the geopark's implementation and conserve the essential functions of the dune landscape.  

Capacity building has contributed to an increased sense of responsibility and commitment from the local community. Nevertheless, insights from local community members highlighted the urgent need for economic benefits and future stability for the geopark through more defined development plans and increased community involvement. This study highlights the importance of incorporating community insights early in the development process  and promote bottom-up approaches, providing greater opportunities for active participation in geopark planning, management, and monitoring.

How to cite: Lin, T.-Y. and van Onselen, V.: Local insights into community participation and Eco-DRR strategies for sustainable geopark management at Caota Sand Dunes Geopark, Taiwan, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2990, https://doi.org/10.5194/egusphere-egu24-2990, 2024.

EGU24-3038 | Posters on site | ITS4.4/ERE6.4 | Highlight

Alterations of urban greenspace and heat stress risk during Hanoi's Master Plan 2030 implementation 

Yuei-An Liou, Kim-Anh Nguyen, and Duy-Phien Tran

Hanoi City has experienced a remarkable transformation due to implementing Hanoi's Master Plan 2030, which brought forth numerous challenges, notably in preserving urban green space (UGS). The objectives of this work are to (1) explore the changes in UGS distribution, (2) identify areas prone to heat stress by examining abnormal land surface temperature (LST) distributions in conjunction with population vulnerability, and (3) suggest solutions through an advanced UGS management platform. To investigate the UGS changes, we utilized Sentinel-2 satellite images, while the assessment of heat stress risk involved extracting LST data from the thermal infrared band of Landsat 8. Our research was concentrated on the inner region of Hanoi City, tracking UGS alterations from October 2016 to October 2018. The study's evaluation involved utilizing Google Earth images and conducting on-site research.

The results demonstrated a significant decline in woodland and shrubland, decreasing by 1.3% and 4.4%, respectively, while grass cover experienced a growth of 2.4%. Our land cover classification exhibited high accuracy, reaching 96% in 2018 and 88% in 2016. Furthermore, this work unveiled a heightened risk primarily focused in the central inner-city zones, marked by densely populous residential regions and extensive built-up environments. Given that air temperature (Ta) significantly affects human health compared to LST, our forthcoming research will incorporate a spatially continuous Ta dataset to delve deeper into studying heat stress risks. This Ta dataset will be generated through our advanced Ta estimation framework employing Machine Learning algorithms, which have demonstrated exceptional performance. Identifying the heat stress risk patterns is essential, as this draws the attention of city planners, governing bodies, and healthcare institutions.

How to cite: Liou, Y.-A., Nguyen, K.-A., and Tran, D.-P.: Alterations of urban greenspace and heat stress risk during Hanoi's Master Plan 2030 implementation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3038, https://doi.org/10.5194/egusphere-egu24-3038, 2024.

EGU24-3413 | ECS | Posters on site | ITS4.4/ERE6.4

Sustainable Management of Golf Courses in Hanoi City: A Remote Sensing Approach for Monitoring Land Distribution and Dynamics 

Kim-Anh Nguyen, Yuei - An Liou, Minh Khanh Luong, and Nguyen Thanh Hoan

In recent years, the role of golf courses in contributing to the economic growth of various Vietnamese cities, including Hanoi, has gained prominence. Nonetheless, debates persist regarding the environmental and societal impacts of golf course development. While golf courses enhance city aesthetics, attract affluent tourists, and align with zero-carbon initiatives, concerns arise over land use, pesticide application, water resources, farmer displacement, and potential environmental degradation.

This study employs remote sensing data to monitor the spatial and temporal distribution of golf courses in the Hanoi City Metropolitan area. Utilizing multi-satellite data and Geographic Information Systems (GIS), the research aims to detect and analyze the spatial dynamics of golf courses, investigating their evolution and impact on the surrounding regions. The outcomes include a remote sensing-based database of golf courses, an examination of dynamic changes in golf course lands over decades, and an assessment of land conversion to golf courses and its consequences. This research is crucial for sustainable golf course management and environmental conservation, providing insights for informed decision-making to achieve environmental sustainability in golf course development.

How to cite: Nguyen, K.-A., Liou, Y.-A., Luong, M. K., and Hoan, N. T.: Sustainable Management of Golf Courses in Hanoi City: A Remote Sensing Approach for Monitoring Land Distribution and Dynamics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3413, https://doi.org/10.5194/egusphere-egu24-3413, 2024.

EGU24-5654 | ECS | Orals | ITS4.4/ERE6.4

Exploring community-based adaptive approaches in agriculture and water management to address salinity impacts in coastal Bangladesh 

Khusnur Jahan Shapna, Jianfeng Li, Saifullah Khandker, and Md Lokman Hossain

The coastal region of Bangladesh is greatly impacted by high soil and water salinity levels, worsened by tropical cyclones and rising sea levels. Understanding the extent of salinity and its challenges is vital for sustainable agriculture and safe drinking water. This study employed both quantitative methods, focusing on soil and water parameters, as well as qualitative approaches such as focus group discussions (FGDs) and key informant interviews (KIIs). The objectives of this research were to assess soil and water salinity, and soil nutrient content, and to investigate adaptive practices and challenges in agriculture and drinking water management in six sub-districts in the southwestern coastal region of Bangladesh. Qualitative information obtained from 18 FGDs and 16 KIIs was assessed by thematic and content analysis to evaluate the community-based adaptive techniques and challenges in sustainable agriculture and water management in the salinization-affected region. Using a one-way ANOVA and post hoc Tukey tests, the soil and water parameters of the collected 165 soil samples (croplands), and 132 water samples (ponds and canals) were analyzed to assess the soil nutrients (nitrogen, phosphorus, and potassium) and soil and water salinity in six sub-districts.

The soil nitrogen, phosphorus, and potassium contents exhibited significant variations, whereas there was no notable difference in soil salinity content across the studied sub-districts. Upon examination of pond water salinity levels, significant variations were observed among the six sub-districts. The salinity levels (ds cm-1) in pond water ranged between 13 and 14 ds cm-1 in these sub-districts. Among them, Shyamnagar recorded the highest level of pond water salinity (13.99), followed by Assasuni (13.96), Dacope (13.91), Koyra (13.58), Morrelganj (13.33), and Mongla (13.19) sub-districts. Pairwise comparisons of salinity levels in pond and canal water show that the salinity level in most water samples varied significantly among sub-districts.

Respondents in FGDs and KIIs consistently identified salinity as a major challenge in agriculture and drinking water in the studied sub-districts. Additionally, climate-induced stresses, such as untimely precipitation, and pest outbreaks during droughts were recognized as significant issues impacting sustainable agriculture. In terms of adaptive practices, this research emphasizes the feasibility of rainwater harvesting as an effective technique for managing drinking water and mitigating water and soil salinity. This approach offers a viable solution for addressing water scarcity and salinity issues in the coastal region. One notable finding in agriculture from the research is the positive impact of organic fertilizer (vermicompost) in reducing soil salinity levels. This finding highlights the potential of utilizing organic fertilizer as a nature-based solution to mitigate salinity in the affected regions of Bangladesh and globally. By adopting such adaptive strategies, the region can promote resilient agricultural systems and ensure sustainable water management.

In summary, the study highlights the prevalence of soil and water salinity in the coastal region of Bangladesh and the associated challenges it poses for agriculture and drinking water management. The research emphasizes the significance of adaptive practices, specifically rainwater harvesting and organic fertilizer, as a practical solution to address water scarcity and salinity issues in the region.

How to cite: Shapna, K. J., Li, J., Khandker, S., and Hossain, M. L.: Exploring community-based adaptive approaches in agriculture and water management to address salinity impacts in coastal Bangladesh, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5654, https://doi.org/10.5194/egusphere-egu24-5654, 2024.

EGU24-6142 | ECS | Orals | ITS4.4/ERE6.4 | Highlight

A Community-Led Approach to Environmental Monitoring and Adaptive Capacity Building in the Coastal Bend Region of Texas, USA 

Michelle Hummel, Oswald Jenewein, Karabi Bezboruah, Yonghe Liu, Kathryn Masten, Byeongseong Choi, and Amruta Sakalker

The Coastal Bend Region (CBR) of Texas is vulnerable to acute and chronic environmental stressors stemming from natural and industrial sources, including flooding and erosion from high tides, storm surge events, and ship traffic, as well as higher levels of air and water pollution due to expansion of nearby industrial operations. Communities in the CBR are diverse, spanning a range of sizes, demographics, and geographies, and have varying levels of exposure, vulnerability, and capacity to respond and adapt to the cumulative threats posed by climate change and industrial expansion. Currently, residents of the CBR are engaging in a variety of community organizing and advocacy efforts, including through existing and newly established community-based organizations. These organizations span a range of experience levels and capacities in interfacing with local decision-makers and engaging in collective action to address environmental threats, but all have expressed a need for more comprehensive data about environmental and industrial conditions to advocate for and make informed decisions about risk reduction strategies that mitigate negative impacts on air, water, and land resources.

Here, we discuss an ongoing research program to examine how smart and connected technologies can be integrated into regional communication and advocacy networks to increase awareness of natural and anthropogenic hazards and build community adaptive capacity equitably among the diverse residents in the CBR. We first present the results of a year-long planning study conducted in partnership with one CBR community to (1) evaluate the structure and function of the local communication, information-sharing, and policy-making networks and (2) co-develop a real-time, wireless sensor network and community dashboard to monitor environmental conditions. This study led to the formation of interdisciplinary, academic-civic partnerships that centered community needs in the design and implementation of the research objectives. We then discuss challenges and opportunities in expanding this work to the regional scale to engage a broader diversity of CBR residents using a bottom-up, participatory design approach, with the goal of supporting frontline communities as they advocate for more sustainable and equitable policies for hazard management.

How to cite: Hummel, M., Jenewein, O., Bezboruah, K., Liu, Y., Masten, K., Choi, B., and Sakalker, A.: A Community-Led Approach to Environmental Monitoring and Adaptive Capacity Building in the Coastal Bend Region of Texas, USA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6142, https://doi.org/10.5194/egusphere-egu24-6142, 2024.

EGU24-7722 | Posters on site | ITS4.4/ERE6.4

Participatory multi-criteria decision making for optimal siting of dams 

Fabio Castelli, Matteo Masi, and Chiara Arrighi

The impacts of increasing water scarcity as a consequence of climate change determine an urgent demand
for enhanced management of water resources. The construction of new artificial reservoirs to expand
water storage capacity represents a pivotal strategy to address these pressing concerns and fulfil the
community&#39;s needs for drinking water, irrigation, energy generation, and flood risk mitigation. The
selection of sites for new reservoirs can be merely based on topographic and hydrologic assessments.
However, the identification of optimal locations requires a comprehensive evaluation that considers a
multitude of often-competing factors that encompass bio-physical, socio-economic, regulatory, and
environmental aspects. The involvement of communities and citizens in the initial stages of the decision-
making process is crucial. This study introduces a methodology based on multi-criteria decision making
(MCDM), to identify optimal reservoir locations, simultaneously addressing all the aforementioned aspects
through community engagement. This methodology employs an automated algorithm to analyse a large
pool of potential sites, through a Digital Elevation Model (DEM) integrated with hydrologic simulations. For
each site the algorithm optimizes the location and orientation of the dam and calculate the geometrical
characteristics, such as the dam length, dam volume and the water storage volume. In a subsequent step, a
MCDM analysis is conducted to rank the sites based on quantitative selection criteria established through a
comprehensive territorial analysis and hydrological modelling. These criteria include geometric and
morphological aspects (e.g., reservoir volume), hydrological indicators (e.g., water balance, flood
mitigation), anthropization (e.g., population density, infrastructures), landscape, archaeological heritage,
ecology, environmental components, and potential natural hazards. To foster community engagement, we
developed a web-based survey platform that enables the collection of diverse perspectives from various
stakeholders, communities and citizens, allowing them to express their opinions on the relative importance
of each individual criterion. The application of this methodology is demonstrated through a case study in
the Arno river basin, Italy, showcasing its effectiveness in identifying the most suitable reservoir locations
while targeting the highest environmental preservation and community well-being.

How to cite: Castelli, F., Masi, M., and Arrighi, C.: Participatory multi-criteria decision making for optimal siting of dams, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7722, https://doi.org/10.5194/egusphere-egu24-7722, 2024.

EGU24-12726 | ECS | Posters on site | ITS4.4/ERE6.4 | Highlight

Distributed databases to improve data sovereignty in citizen science 

Julien Malard-Adam, ஷீஜா (Sheeja) குமார் (Kumar), Wietske Medema, நல்லுசாமி (Nallusamy) ஆனந்தராஜா (Anandaraja), Joel Harms, and Johanna Dipple

Citizen science is important for community-led science. However, the knowledge and costs required to configure and manage servers for data management in such community-led projects are major barriers to the adoption of citizen science-based approaches at a larger scale. At the same time, the centralisation of communities’ data onto project servers (whether rented in « the could » or on-premise) also poses questions regarding data sovereignty true community ownership of citizen science projects. (Who owns the data? Who has the power to give or revoke access to it? How will data be accessible once the principal investigators and funding are gone?)

Distributed databases, where data is stored directly on users’ devices and shared in a peer-to-peer network, can address some of these issues by bypassing the need to rely on a centralised server for user authentication and data storage and transmission. While this approach offer solutions to some long-standing challenges of centralised approaches to data collection, distributed databases also bring their own limitations. This presentation will discuss three major questions and paradigm shifts related to the adoption of distributed databases for citizen science, namely authorisation, discovery and accessibility. Approaches for addressing these in the context of community-led participatory projects will be discussed, and examples of using Constellation distributed database software for case studies in citizen science and data sharing will be provided.

How to cite: Malard-Adam, J., குமார் (Kumar), ஷ. (., Medema, W., ஆனந்தராஜா (Anandaraja), ந. (., Harms, J., and Dipple, J.: Distributed databases to improve data sovereignty in citizen science, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12726, https://doi.org/10.5194/egusphere-egu24-12726, 2024.

EGU24-13529 | ECS | Posters on site | ITS4.4/ERE6.4

A serious game approach to promote non-traditional solutions and ecosystem services for water adaptive management 

Gabriel Silva, Marcos Benso, Pedro Silva, and Eduardo Mendiondo

Water problems related to floods, droughts, water quality, and supply demand require methods focused on harnessing the inherent capabilities of ecosystems to cope with water related problems and the ecosystems natural capability to address water-related challenges by leveraging this advantage on maintaining ecological balance. Although it demands more investments than traditional approaches, Nature-based Solutions (NbS) has a significant impact on promoting sustainability and its success relies on careful planning, collaboration with local communities, and adaptive management strategies. This study aims to develop an engaging and educational serious game to demonstrate how NbS can serve as a strategic approach for fostering the development of smart and resilient cities in response to the challenges posed by climate change, water-related risks, and disasters. By engaging individuals in a virtual environment, serious games can effectively communicate the consequences of various water-related decisions and encourage sustainable practices among the public. Thus, designed for a diverse audience, including students, urban planners, decision-makers, and the general public, the game utilizes realistic mathematical models to simulate climate change scenarios and extreme weather events. Yet, players can make challenging decisions in implementing NbS, like creating urban green zones, watershed management, and aquatic ecosystem restoration. The game can also incorporate real-world data for specific geographic areas, emphasizing the effectiveness of NbS in regional contexts. Finally, the game incorporates water modeling techniques, leveraging the robust capabilities of HydroPol2D and/or HyMAP models. These models enable the simulation of water runoff in two dimensions by utilizing Digital Elevation Models (DEMs), land use and rainfall data. Furthermore, collaboration with local communities and adaptive management strategies are crucial components, showcasing the importance of stakeholder engagement.

How to cite: Silva, G., Benso, M., Silva, P., and Mendiondo, E.: A serious game approach to promote non-traditional solutions and ecosystem services for water adaptive management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13529, https://doi.org/10.5194/egusphere-egu24-13529, 2024.

EGU24-18315 | Orals | ITS4.4/ERE6.4

Advancing Local Disaster Resilience Strategies: A Transdisciplinary Approach 

Khamarrul Azahari Razak, Liyana Hayatun Syamila Ramlee, Hannani Yusra Sapiee, Yuet Mei Siow, Rahsidi Sabri Muda, Rabieahtul Abu Bakar, Zakaria Mohamed, Zamri Ramli, and Che Siti Noor Koh Poh Lee

This study addresses the urgency to re-strategize our local action to prevent future climatic risk as a result of extreme weather events, urbanization, anthropogenic activities in a changing climate. While progress has been made in implementing the Sendai Framework for Disaster Risk Reduction since its adoption in 2015, no country is on track to achieve the outcome and goal by 2030. Malaysia is not an exception. A holistic approach to multi-scale disaster risk reduction and climate resilience is critically needed to examine new prospective agenda for accelerated action. This study provides a new insight into galvanizing technological advancement, multi-tier partnership and community-led approach to entail more coordinated and programmatic action towards translating resilience thinking approach into risk-informed decision-making. Equipping cities and communities with knowledge and capabilities to manage complexity of risks is a step forward to re-build a resilient society and rejuvenate resilience thinking. UNDRR’s global reports indicated that by providing a 24-hour early warning can reduce the resulting damage by 30%. Therefore, investing in the development of people-centered, end-to-end, multi-hazard early warning system (EWS) is highly regarded to support the 2027’s Early Warning for All agenda. This study highlights smart partnership into co-designing, co-developing, and co-implementing an impact-based EWS for geological risk in Jerai Geopark (Yan, Kedah), towards rejuvenating local resilience strategy through the development of DRR Yan Model and Resilience Living Lab in a national geological heritage area dominated by tourism industry. The key for successful community-led disaster risk reduction (CLDRR) lies in maintaining interest in resilience culture and motivation for local agenda at the grassroot level. We also demonstrate community-led DRR program with a unique localization strategy that addresses dam-related disaster risk. This study acknowledged that 40% of large dams in Malaysia are aging, necessitating new approaches to dam safety. Moreover, regional benchmarking for technological-based sociotechnical systems enabled by collaborative foresight and disaster informatics are a way forward to assess future emerging hazards, systemic risk, and compounding disaster. With good risk governance, evidence-based risk investment, and risk-informed decision making, as supported by all-of-society approach particularly in advancing a new partnership model for the public-private-academia-civil society, this study reports current demands for de-risk strategies that shall be systematically incorporated into decision-making, governance, and investments. The development of new strategies, actions, and initiatives are mutually explored towards inculcating targeted investments related to systemic risk reduction, and mainstreaming urban development planning of unattended risks should be made based on science, coupled by the Local, Traditional and Indigenous Knowledge (LTIK) approach. The de-risk investment efforts often jeopardize by a series of sudden, large-scale geological-induced disaster, resulting into the prolonged economic impacts continues to escalate and underscores the multi-scale investment for DRR agenda at a local level. By adopting a transdisciplinary approach to DRR and forward-looking risk-informed approach, this vulnerable region can further develop its resilience capacity to tackle complex challenges of climate risks. As a conclusion, risk-informed pathway in development planning, and a paradigm shift, can contribute towards promoting equitable and sustainable resilience in geologically risk sensitive regions.

How to cite: Razak, K. A., Ramlee, L. H. S., Sapiee, H. Y., Siow, Y. M., Muda, R. S., Abu Bakar, R., Mohamed, Z., Ramli, Z., and Koh Poh Lee, C. S. N.: Advancing Local Disaster Resilience Strategies: A Transdisciplinary Approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18315, https://doi.org/10.5194/egusphere-egu24-18315, 2024.

EGU24-18385 | ECS | Posters on site | ITS4.4/ERE6.4

Are Brazilian schools safe? Incorporating school resilience as response to water related disasters and adaptive management 

Marcos Roberto Benso, Jamil Alexandre Ayach Anache, Denise Taffarello, Suzana Maria Gico Lima Montenegro, Greicelene Jesus da Silva, and Eduardo Mário Mendiondo

In the event of disasters such as droughts, floods, and landslides, social sectors including housing, education, and social protection are the most affected. Here, we present a project that incorporates the school system as a vulnerable sector to water insecurity and a tool to promote resilience. In this sense, we adopt the concept of water security defined by the United Nations (UN), including the availability of water to support socioeconomic development, the preservation of aquatic ecosystems, and the ability to withstand a reasonable amount of risk from floods and droughts. Planning for the supply and use of water at the national level should be based on the four elements of water security. This project is contextualized at the Brazilian National Observatory for Adaptive Water Security and Management (ONSEAdapta) (https://onseadapta.org/en/elementor-642/). Given the importance of schools, the objective of this project is to propose a conceptual framework to incorporate school resilience as a response to water-related disasters and adaptive management. The proposed methodology is divided into two approaches. First, a top-down approach is proposed to collect data from the annual school census of Brazilian schools that is provided at school level by the Anisio Teixeira National Institute of Educational Research and Studies (INEP) and water security data from the National Water and Sanitation Agency of Brazil (ANA). Second, a bottom-up approach is proposed to survey educators and members of the school community to depict how water security is incorporated into schools, what initiatives promote the participation of school and society, and the main implications for reducing disaster risk, building capacity, and increasing disaster resilience. In Brazil, according to the 2022 school census, there were 184,331 schools that accommodated 22% of the Brazilian population (~47 million students). To propose the concept of school resilience as a dimension of water security, we located and diagnosed the number of schools that are in water insecurity by combining the Brazilian water security index (ISH) with the georeferenced map of Brazilian schools. Using the ISH that combines human, ecosystemic, economic, and resilience dimensions, we identified that 11.93, 14.40, 16.04 million students are under minimum to low, medium, and high to maximum water security, respectively. This analysis unveils that almost 28% of Brazilian students are below a low level of water security. These students come from preschool, elementary and secondary education in rural and urban areas. We conceptualize the assessment of school resilience using a comprehensive framework that considers infrastructure, level of water insecurity, impacts on school, emergency preparedness, and community involvement. To foster community involvement and scientific contributions, the next step is the creation of an online platform to promote citizen science, collect data, and engage with educators. By fostering participatory citizenship education in schools, this project aims to create a resilient and well-informed community capable of mitigating the impact of disasters and contributing to general water security and adaptive management.

How to cite: Benso, M. R., Anache, J. A. A., Taffarello, D., Montenegro, S. M. G. L., Silva, G. J. D., and Mendiondo, E. M.: Are Brazilian schools safe? Incorporating school resilience as response to water related disasters and adaptive management, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18385, https://doi.org/10.5194/egusphere-egu24-18385, 2024.

EGU24-19795 | Orals | ITS4.4/ERE6.4 | Highlight

Social and environmental benefits of regenerative design 

Stanislava Boskovic, Jeni Giambona, Ana Mijic, and Doug Baldock

Cities are major contributors to climate change through greenhouse gas emissions, notwithstanding other sources of pollution, conditioning planet health and citizens wellbeing. The increase in urban growth and urbanization results in an expansion of urban hazards - including water scarcity, air pollution and other environmental issues. Therefore, to respond to the need for new urban development, it is necessary to introduce a new systems-based approach able not only to maintain the existing environmental indicators, but to guarantee their improvement. 

To address this complexity, in this work we explore Regenerative Design (RD) definition, scale and proprieties to rethink the ecological challenges we face in a holistic and systematic manner.  Regenerative Design approach, in this study, aspires to demonstrate that order to achieve net-positive outcomes and address social and ecological issues, it is necessary to move beyond the only intention of environmental harm mitigation. The regenerative design process leads to design processes that utilize the insights and relationships of ecological systems of the place as the basis for projects in which human actions positively contribute to the self-healing properties of nature. Therefore, an integration of nature-inspired solutions throughout the design process is required.

This study evidence that a transformative shift towards regenerative design requires not only a change in way of thinking and practice, but also in worldviews and values. It starts with the awareness the way we approach analysis of a design process might not be regenerative. Therefore, there is need for systems change to tackle root causes of degeneration, where the context and the place-based design decisions are of crucial importance.

How to cite: Boskovic, S., Giambona, J., Mijic, A., and Baldock, D.: Social and environmental benefits of regenerative design, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19795, https://doi.org/10.5194/egusphere-egu24-19795, 2024.

EGU24-19975 | ECS | Posters on site | ITS4.4/ERE6.4

Knowledge Co-Creation for Enhanced Ecosystem Services Management on Islands 

Ina Maren Sieber and Cathleen Cybele

Against the backdrop of aggravating environmental challenges, effective ecosystem services (ES) management is crucial for biodiversity conservation, livelihood support, and economic growth. Including citizens, stakeholders and societies in research is gaining popularity as a suitable tool for both informed decision-making and enhanced community resilience. Our study explores the application of knowledge co-creation methodologies to improve ES management. The French Outermost Region of La Réunion, situated in the Indian Ocean, provides an opportune setting for addressing these challenges. Community members, stakeholders, and experts were engaged in a structured, yet flexible knowledge co-creation process to jointly define the potential for cultural ecosystem services (CES) including landscape aesthetics, recreation and eco-tourism.

The collaborative process empowered the community to identify and prioritize ES through initial interviews and focus groups. This informed a participatory GIS mapping exercise, facilitating community involvement in visually representing ecosystem services and their spatial relationships. Based on this work, additional methods were employed to provide the community with information. Expert elicitation validated the community-generated knowledge, incorporating insights from local and regional professionals. In addition, geotagged photos were analysed to assess actual use of cultural ES. This approach ensured a comprehensive understanding of ecosystem interactions, including ecosystem features, capacity of ecosystems to supply ecosystem services and informed options for sustainable development.

Our results contain qualitative and quantitative assessments of CES within the study area: multiple ES maps that show the distribution of ES on spatial scale, coinciding strongly with landscape features. A high appreciation of the coastline with its scenic cliffs and rocky beaches is visible. The inland provides large potential for recreational activities and tourism, including hiking, mountain biking, horse-riding, bird watching and botany. Geotagged photo analysis added the magnitude of visitors, showing popular trails and locations.

 Yet, the application of co-creation for research proves challenging. The joint definition of research focus and the fuzziness of the approach diverge from current modes of environmental (social) sciences. Further, stakeholder engagement requires time and dedication. We find that co-creation provides aspects of community learning and empowerment. This research contributes to the discourse on knowledge co-creation as a valuable tool for addressing environmental challenges and promoting sustainable development. The insights provide a foundation for applying similar methodologies in diverse socio-ecological contexts, opening up new possibilities for community engagement in ecosystem services research.

How to cite: Sieber, I. M. and Cybele, C.: Knowledge Co-Creation for Enhanced Ecosystem Services Management on Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19975, https://doi.org/10.5194/egusphere-egu24-19975, 2024.

EGU24-20423 | ECS | Posters on site | ITS4.4/ERE6.4

Evaluating the Environmental Justice of Tree Canopy Connectivity in Pheonix, Arizona, USA 

Zane Havens and Stephen Macko

Phoenix, Arizona, a metropolis located in the Sonoran Desert in southwester USA, is expected to see major disturbances resulting from global warming, including excessive heat events1 and drought2. Urban Green Infrastructure (UGI) has the potential to help mitigate excessive heat3 yet, as water becomes increasingly scarce, efficiency in both the location and configuration of UGI is critical to maximize its positive benefits.  Well-connected UGI provides more ecosystem services and can better mitigate extreme temperatures in urban areas than poorly connected UGI 4. However, owing in part to the current and anticipated scarcity of water, the distribution and connectivity of this lifesaving resource has the potential to be unjust regarding economically vulnerable communities. The purpose of this study is to determine if there are relationships between the coverage/connectivity of Phoenix UGI and sociodemographic variables associated with vulnerability.  Using a 2010 1m landcover classification raster and the landscapemetrics R package, landscape metrics were calculated for sample plots withing areas zoned for single-family residential homes.  Vulnerability statistics were then apportioned for each plot using 2010 ASTER/CDC Social Vulnerability Index data. These variables were then examined to determine relationships between connectivity and vulnerability using Principal Component Analysis.   

 

1.  Stone, B. et al. Climate change and infrastructure risk: Indoor heat exposure during a concurrent heat wave and blackout event in Phoenix, Arizona.Urban Climate 36, 100787 (2021).

2.  Bolin, B., Seetharam, M. & Pompeii, B. Water resources, climate change, and urban vulnerability: a case study of Phoenix, Arizona. Local Environment 15, 261–279 (2010).

3.  Marando, F. et al. Urban heat island mitigation by green infrastructure in European Functional Urban Areas. Sustainable Cities and Society 77, 103564 (2022).

4.  Debbage, N. & Shepherd, J. M. The urban heat island effect and city contiguity. Computers, Environment and Urban Systems 54, 181–194 (2015).

How to cite: Havens, Z. and Macko, S.: Evaluating the Environmental Justice of Tree Canopy Connectivity in Pheonix, Arizona, USA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20423, https://doi.org/10.5194/egusphere-egu24-20423, 2024.

EGU24-20438 | Orals | ITS4.4/ERE6.4

Monitoring urban agriculture: a nature-based solution to transform city food systems 

Sebastian Eiter, Wendy Fjellstad, and Loes van Schaik

Urban agriculture is a nature-based solution to increase the economic, social and environmental sustainability of cities and city food systems. However, sustainability is difficult to measure, and there is therefore discussion about whether urban agriculture really contributes positively to sustainability. Monitoring data could provide evidence of the impacts of urban agriculture and help inform decision makers about whether and where to prioritise different forms of urban agriculture above competing interests.

Using case examples from five European cities, we identified the challenges involved in monitoring urban agriculture, from selecting indicators and gathering data, to using the results. We found large differences in approach in terms of what topics to monitor and who was responsible, who gathered the data and when, what data was recorded and how they were stored, and how findings were disseminated or published. Based on these experiences, we recommend stronger involvement of existing interest groups and educational institutions in monitoring urban agriculture, and promotion of convenient tools for data collection by citizen science and for long-term data storage.

How to cite: Eiter, S., Fjellstad, W., and van Schaik, L.: Monitoring urban agriculture: a nature-based solution to transform city food systems, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20438, https://doi.org/10.5194/egusphere-egu24-20438, 2024.

This study compares and analyzes the impact of land use changes on ecosystem services and ecological security in different ecological backgrounds in Stockholm and Panjin. Using Morphological Spatial Pattern Analysis (MSPA), Analytic Hierarchy Process, and Circuit Theory, the dynamic changes in ecosystem services and ecological security patterns are assessed in these two regions. Based on the characteristics and land use changes from 2000 to 2020, four scenarios for 2050 are simulated using the PLUS model: Business-as-Usual (BAU), Priority Urban Development (PUD), Priority Ecological Protection (PEP), and Balanced Urban-Ecological Development.The results show that in Panjin, the growth rate of construction land was 21.49% from 2000 to 2020, and when this probability was applied to the transfer probability of Priority Urban Development in the Stockholm region, there was a significant change in the ecological security pattern. In contrast, in Stockholm County, the correlation between the change rates of all land use types and other indicators was weak, suggesting limited influence of these factors on land use changes. However, in Panjin, there was a strong positive correlation between the change rates of construction land, unused land, and population and GDP. This implies that in regions with lower economic levels, there is a higher dependence on ecosystem services and ecological security patterns compared to higher economic regions.Observations reveal an increase in forest and grassland area in Panjin City. However, the distribution of high-value ecological source areas is not concentrated enough and exhibits a high rate of change. In contrast, the Stockholm region has maintained a stable pattern of ecological source areas over the past 20 years. The Stockholm region has developed a relatively reasonable ecological security pattern, which is the result of continuous ecological protection and planning efforts over many years.

How to cite: wu, H.: The impact of urbanization on ecosystem services and ecological security patterns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20661, https://doi.org/10.5194/egusphere-egu24-20661, 2024.

Between March 2016 and September 2020, the Canadian government supported a Southern African Nutritional Initiative (SANI) project in Malawi, Mozambique and Zambia to enable women of reproductive age and children under the age of 5 to  produce, access, store, preserve and process high nutrient food. We report on Zambia’s agricultural component of the project summarizing the key food production techniques used to encourage sustainable agricultural production through the use of smart agricultural practices. These  practices have the potential to allow small farm holders to adapt to climate change and offer opportunities to reduce and remove Green House Gases from these systems in order to contribute to the  Nationally Determined GHG Contributions under the Paris Agreement and meet national food security and development goals. As part of the study, in person training sessions were conducted with participants on smart agricultural practices such as the promotion of local technologies around seed bed preparation of home gardens and orchards, manuring, and the use of local products to control insects, pests and  diseases instead of chemicals. Apart from receiving training in sustainable practices, participants were also trained in food preservation and value addition to harvested produce and grains in order to increase the shelf life and usability of various food types as a way of promoting food security. Anecdotal evidence through follow up field evaluations and food preparation demonstration sessions showed that project participants were adapting  and moving towards achieving a resilient status. These and scale up issues will be discussed in this contribution.

How to cite: chipanshi, A. and chewe, J.: Capturing the synergies among mitigation, adaptation and food security through smart agriculture practices in Muchinga Province of Zambia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20852, https://doi.org/10.5194/egusphere-egu24-20852, 2024.

Professional societies can play important roles in society's climate change response. Sitting at the junction of scientific innovation, policy advocacy, and community engagement, professional societies are uniquely positioned to bridge the gap between principal investigators (PIs), governments, and local communities. As non-governmental actors, these groups streamline the transfer of research into actionable strategies by facilitating knowledge exchange, standardizing methodologies, and fostering multi-stakeholder collaborations.

This presentation will outline how professional societies can amplify the reach and relevance of scientific endeavors and help ensure that community priorities are at the forefront of environmental policies and practices. It will argue for their enhanced involvement in driving interdisciplinary approaches, advocating for inclusive and informed policy-making, and empowering communities through accessible, science-based solutions. The session aims to inspire a cohesive dialogue among community leaders, scientists, and policymakers, highlighting the necessity of a united front to effectively address the pressing environmental challenges of our times. Lastly, the talk will highlight the joint Optica-AGU Global Environmental Measurement and Monitoring Initiative.

How to cite: Lang, D. and Shimamoto, M.: Amplifying Impact: The Role of Professional Societies in Community-Led Environmental Science, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22285, https://doi.org/10.5194/egusphere-egu24-22285, 2024.

 Highlights

  • We attribute variation across global climate mitigation scenarios to three factors
  • The three factors are climate ambition, scenario background and model choice
  • Many indicators are well-explained by the average effects of one or two factors
  • We also calculate the residual not explained by these average effects
  • This shows which indicators give outliers for some specific input combinations

Abstract

We attribute variations in key energy sector indicators across global climate mitigation scenarios to climate ambition, assumptions in background socioeconomic scenarios, differences between models and an unattributed portion that depends on the interaction between these. The scenarios assessed have been generated by Integrated Assessment Models (IAMs) as part of a model intercomparison project exploring the Shared Socio-economic Pathways (SSPs) used by the climate science community. Climate ambition plays the most significant role in explaining many energy-related indicators, particularly those relevant to overall energy supply, the use of fossil fuels, final energy carriers and emissions. The role of socioeconomic background scenarios is more prominent for indicators influenced by population and GDP growth, such as those relating to final energy demand and nuclear energy. Variations across some indicators, including hydro, solar and wind generation, are largely attributable to inter-model differences. Our Shapley-Owen decomposition gives an unexplained residual not due to the average effects of the other factors, highlighting some (such as the use of carbon capture and storage (CCS) for fossil fuels, or adopting hydrogen as an energy carrier) with outlier results for particular ambition-scenario-model combinations. This suggests guidance to policymakers on these indicators is the least robust.

Graphical Abstract

Keywords

Energy transition, climate change mitigation, Integrated Assessment Models, Shapley-Owen decomposition

How to cite: Al Khourdajie, A., Skea, J., and Green, R.: Climate ambition, background scenario or the model? Attribution of the variance of energy-related indicators in global scenarios, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-656, https://doi.org/10.5194/egusphere-egu24-656, 2024.

This essay navigates the critical juncture of climate change mitigation and sustainable construction practices, employing a comprehensive analytical framework centered on the robust incorporation of a Life Cycle Assessment (LCA). The exploration is rooted in a profound understanding of the construction industry's substantial contribution, amounting to 38% of global emissions, with a specific emphasis on residential buildings and their consequential carbon footprint.

The advocacy for the implementation of a standardized carbon inventory and a meticulously defined system boundary constitutes a foundational aspect of this analysis. This endeavor draws upon well-established ISO standards, simultaneously subjecting the widely acknowledged LEED V4.1 to a comprehensive and rigorous critical examination. The utilization of precise carbon calculations, facilitated by sophisticated regression formulas, emerges as a pivotal tool, enabling the identification of salient life cycle hotspots within the construction sector. In advancing a proactive approach to carbon reduction, this essay delves into historical trends and introduces an institutional management framework, covering GRESB and SDGs. This multifaceted strategy not only addresses immediate challenges but strategically positions organizations within the construction industry to thrive. It adeptly navigates transition risks and seamlessly integrates sustainable practices, thus fostering a transformative paradigm within the sector. Within the specific context of Taiwan, where the majority of green buildings align with the widely accepted LEED system, the mission is unequivocal. The objective is to augment the LEED framework through the judicious incorporation of a tailored life cycle assessment that is attuned to the unique needs of the Taiwanese construction landscape. The overarching goal remains the establishment of an equitable, transparent, and easily comprehensible system, not only to present opportunities but also to effectively mitigate risks for construction companies.

The essay underscores the imperative of ensuring that buildings actively contribute to communities and the environment. This initiative aligns harmoniously with the ambitious target of achieving net-zero emissions by 2050, thereby engendering a positive and enduring impact for both present and future generations. The transformative narrative presented in this exploration emphasizes the pivotal role of sustainable construction practices in reshaping the trajectory of the construction industry towards a resilient and environmentally conscious future.

How to cite: Wang, Y. and Tung, C.: Reducing Transition Risks: A Life Cycle Assessment Approach to Residential Buildings with Integrated Sustainable Framework, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3063, https://doi.org/10.5194/egusphere-egu24-3063, 2024.

EGU24-4387 | Orals | ITS3.27/ERE6.6

Adaptive Strategies to Reconcile Diverse Equity Preferences in Climate Policies 

Palok Biswas, Jazmin Zatarain Salazar, and Jan Kwakkel

Normative uncertainty, which arises from diverse ethical perspectives and uncertainty about distributional outcomes, poses a significant hurdle in climate policy negotiations. Such uncertainty illustrates the core challenge of achieving agreement on the moral principles or equity considerations that should guide the development of climate policies.

Integrated Assessment Models (IAMs), while influential in shaping decisions, fall short in factoring in this normative uncertainty in climate policies. To address this issue, we developed an IAM framework called JUSTICE. JUSTICE leverages the economic insights of the RICE50+ model to explicitly account for spatiotemporal heterogeneity alongside probabilistic forecasting of the FaIR climate model for a better representation of climate uncertainty. We also reformulate the Social Welfare Function (SWF) in light of four distributive justice principles - Utilitarian, Sufficientarian, Egalitarian, and Prioritarian - to encapsulate the ethical pluralism of different stakeholders. 

We search for adaptive mitigation policies by assimilating two established decision-making frameworks: Multi-Objective Robust Decision-Making (MORDM) and Evolutionary Multi-Objective Direct Policy Search (EMODPS). MORDM rigorously tests potential policies against deep uncertainties to find robust, Pareto-optimal choices. At the same time, EMODPS fine-tunes strategies to reconcile stakeholders' diverse objectives, ensuring policies are adaptive and robust. 

Our findings demonstrate that adaptive policies facilitate deliberation. They identify common ground among policymakers with diverse perspectives by being robust across multiple realizations of deep uncertainties and flexible enough to accommodate conflicting ethical perspectives. Our approach designs climate policies that are both inclusive and adaptive, ensuring they account for immediate necessities while remaining responsive to unfolding future challenges—thereby upholding the tenets of both intra and intergenerational justice. 

 In summary, our study underscores the pivotal role of normative clarity in facilitating stakeholder dialogue and ensuring that climate policies are scientifically sound and socially equitable. Incorporating diverse normative perspectives and acknowledging normative uncertainties, our adaptive strategies limit overconfidence in climate policies, promote inclusivity without subjecting individuals to undue risks, and redefine the application of IAMs in crafting fair and just climate policies.

 

Keywords: Integrated Assessment Models, Climate policy, Distributive justice, Deep Uncertainty, Adaptive strategies, Social Welfare Function, Robust decision-making.

How to cite: Biswas, P., Zatarain Salazar, J., and Kwakkel, J.: Adaptive Strategies to Reconcile Diverse Equity Preferences in Climate Policies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4387, https://doi.org/10.5194/egusphere-egu24-4387, 2024.

EGU24-5065 | ECS | Posters on site | ITS3.27/ERE6.6

MEDUSA - Modelling Equity and DistribUtional impacts for Socioeconomic Analysis 

Eva Alonso-Epelde, Clàudia Rodés, and María Moyano-Reina

Addressing the major challenges of the 21st century, such as climate change, will require complex and ambitious policies that promote social justice. To do so, it is necessary to design efficient policies that do not exacerbate existing inequalities, such as gender or income inequality. In this sense, it is essential to carry out impact analyses of policies from a holistic perspective that evaluates the economy, energy, land, and water systems in an integrated manner before implementing them. While Integrated Assessment Models (IAMs) have been a fundamental tool in the past, micro-simulation models for distributional analysis have the advantage of providing more heterogeneous results that help to more robustly identify the socio-economic impacts of the policies to be implemented. These analyses make it possible to identify the people who will be most affected by policies and to implement compensatory measures to make the policy fairer. Thus, the combination of both models (IAMs and microsimulation models) can provide valuable results for decision making.  MEDUSA is an R package that allows the development of distributional analyses in isolation or in connection with other models such as GCAM. Its extensive database allows for highly disaggregated results, taking into account numerous socio-economic and demographic characteristics of households, such as income level, place of residence, type of family or the degree of feminisation of the household. At the moment, the prototype works for Spain, but the idea is to extend it to all EU countries in the short term. However, the package could be extended to all countries that are able to provide the raw data of the model.

How to cite: Alonso-Epelde, E., Rodés, C., and Moyano-Reina, M.: MEDUSA - Modelling Equity and DistribUtional impacts for Socioeconomic Analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5065, https://doi.org/10.5194/egusphere-egu24-5065, 2024.

EGU24-9358 | ECS | Orals | ITS3.27/ERE6.6

Air quality, health and equity impacts of transport electrification in the U.S. Midwest.  

Sara F Camilleri, Anastasia Montgomery, Maxime Visa, Jordan L Schnell, Zac Adelman, Mark Janssen, Emily Grubert, Susan C Anenberg, and Daniel E Horton

Chronic traffic related air pollution (TRAP) exposure is linked to various adverse health outcomes including pediatric and adult asthma incidence, but more importantly can also lead to premature mortality. In the U.S., the majority of people living close to high volume and density roadways are people of color who are exposed to disproportionate levels of associated health harming primary and secondary air pollutants such as NOx (NO + NO2; key precursors for O3 formation) and PM2.5 as well as greenhouse gases (e.g. CO2). Both heavy- and light-duty vehicles (HDVs/LDVs) contribute to on-road TRAP but on a per vehicle basis, the associated air quality and public health impacts are larger for HDVs. One potential climate mitigation strategy is the shift of the transportation sector to battery powered alternatives (EVs). However, the associated air quality, health and equity implications of such a transition are not well understood and lack characterization at fine intra-urban spatial scales.

Given non-linear atmospheric chemistry associated with the formation of secondary pollutants (e.g O3), and the steep spatial gradients exhibited by short lived TRAP (e.g.  NO2), here we use the two-way coupled Weather Research Forecast and Community Multiscale Air Quality (WRF-CMAQ) chemical transport model at 1.3 km to determine changes in simulated NO2, O3 and PM2.5 concentrations from the electrification of 30% of HDVs and LDVs over a central U.S. Midwestern domain. We represent changes in on-road, refueling and idling emissions as well as power plant emissions from the increased electricity demand needed for charging. Altered emissions are then used as inputs to run a month-long simulation for each season. Incorporating high resolution concentration changes with census tract level health data, we estimate changes in health impacts at the census tract level and across different population subgroups.

We find that electrifying 30% of primarily diesel-fueled HDVs reduces NOx emissions by a factor of 10 for each vehicle mile compared to the NOx reductions associated with electrifying 30% of LDVs. We simulate domain-wide annual mean NO2 (~-10%) and PM2.5 (~-2%) reductions that peak along major roadways, however MDA8O3 concentrations increase in urban cores. If 30% HDVs and LDVs are electrified, we estimate that 1,120 and 170 annual premature deaths linked to NO2 and PM2.5 would be avoided, respectively while 80 annual premature deaths associated with MDA8O3 would be added. Additionally, we find that the largest simulated air quality and health benefits are within communities of color. Notably, we find that while the domain as a whole is only 12% Black, communities with the largest NO2-related health benefits are 45% Black.   

Our results demonstrate that incentives aimed at reducing transportation related emissions, especially from HDVs, are beneficial from a climate perspective but also from an air quality, health and economic perspective with the potential to reduce long standing environmental injustices.

How to cite: Camilleri, S. F., Montgomery, A., Visa, M., Schnell, J. L., Adelman, Z., Janssen, M., Grubert, E., Anenberg, S. C., and Horton, D. E.: Air quality, health and equity impacts of transport electrification in the U.S. Midwest. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9358, https://doi.org/10.5194/egusphere-egu24-9358, 2024.

EGU24-10785 | Orals | ITS3.27/ERE6.6

Can energy and environmental taxation be progressive in the EU? 

Xaquín García-Muros, Eva Alonso-Epelde, Mikel González-Eguino, and Alejandro Rodríguez-Zúñiga

The success of the targets established in the European Green Deal depends on the correct design of ambitious policies that utilize all available instruments, including energy and environmental taxation. In the “Fit for 55” package, the EC proposed a deep reform of the Energy Taxation Directive (New ETD) to update the current taxation and align it with current environmental goals. However, due to the war in Ukraine, the energy crisis, and the risk of regressive effects the current proposal of the EC is stalled. Therefore, this analysis seeks to provide new evidence from a microsimulation model developed to assess the direct, overnight distributional impacts of the proposed new ETD reform on households. Our aim is to explore whether the proposed EU-level polluter pays instruments can be designed to achieve progressive distributional impacts, to identify policy options that ensure they strengthen social justice without undermining it, and thereby remove social barriers. Moreover, we explore a dimension often underrepresented in distributional analyses, namely gender. Our results indicate that, with the correct design from the outset, environmental tax reforms can be progressive and not increase current inequalities between and within Member States of the EU, including those related to gender.

How to cite: García-Muros, X., Alonso-Epelde, E., González-Eguino, M., and Rodríguez-Zúñiga, A.: Can energy and environmental taxation be progressive in the EU?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10785, https://doi.org/10.5194/egusphere-egu24-10785, 2024.

EGU24-12512 | ECS | Orals | ITS3.27/ERE6.6 | Highlight

Why representing gender (in)equality in climate change scenarios matters for the challenges space   

Marina Andrijevic, Caroline Zimm, Jonathan Moyer, Raya Muttarak, and Shonali Pachauri

Socioeconomic challenges to adaptation and mitigation partly hinge on gender (in)equality. A world of equal opportunities for self-realization would be a markedly different place, in ways that are of substantial relevance for adressing climate change. The opposite holds too: in a world of stagnating, or worsening gender inequality, differences in access to resources, education or employment may reduce capacities of societies to both mitigate and adapt.  

Integrated assessment and climate impact models rely heavily on scenarios to understand implications of different socioeconomic futures. In the context of gender equality, these models and scenarios can also serve as tools for broadening our understanding of how societies’ capacities to adapt to and mitigate climate change are enabled or constrained if, broadly speaking, half of their population would gain access to or be further deprived of resources and decision-making power.

In this paper, we propose that the dominant framework of socioeconomic scenarios – the Shared Socioeconomic Pathways (SSPs) – should be extended to explicitly represent indicators of gender equality and their interlinkages with other facets of development. The original narratives underlying the SSP scenarios do feature assumptions about gender equality as part of the demographic elements, with educational attainment and its effect on reducing fertility and therefore population size as the main driver of socio-economic changes (O’Neill et al., 2017). However, only a systematic incorporation into narratives and endogenization of gender (in)equality, can enable the scenarios to reflect ways in which different levels of gender equality could increase or reduce challenges to adaptation and mitigation, and the implications of these challenges for dealing with climate risks. This also applies for other scenario-based work in sustainability and climate change research, for example in devising local energy transition policies whose justice element might be contingent on whether they consider gender aspects. The need for more nuanced accounts of gender has also been highlighted in the context of representation of inequalities in Integrated Assessment Model (IAMs), where gender equality is highlighted as one of the crucial factors when considering climate impacts and policies, their distributional implications and costs (Emmerling and Tavoni, 2021).  

We cover some of the myriad connections between gender and climate from the literature to build the case for why comprehensive assessments of future risks of climate change and of socioeconomic development can benefit from more concrete incorporation of gender aspects in their analyses. We discuss adaptation and mitigation challenges and their interplay with gender. A particular focus is on quantitative models of future societal transformations and assessments of their implications for climate change. We then argue that scenarios can help imagine a world of parity or lack thereof, and show how the SSP framework may change after accounting for gender equality. At the end we discuss how these conceptual and practical advances can feed into more nuanced climate change research and better-informed policy options. 

How to cite: Andrijevic, M., Zimm, C., Moyer, J., Muttarak, R., and Pachauri, S.: Why representing gender (in)equality in climate change scenarios matters for the challenges space  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12512, https://doi.org/10.5194/egusphere-egu24-12512, 2024.

EGU24-15327 | Orals | ITS3.27/ERE6.6 | Highlight

Modeling Dynamic Systems for Sustainable Development  

Noelle Selin, Amanda Giang, and William Clark

We summarize recent progress in dynamic modeling of nature-society systems to inform efforts towards sustainable development.  Drawing on lessons learned from a series of virtual workshops and a journal Special Feature, we identify and highlight examples of novel methods and advances, focusing on four stages of modeling practice -- defining purpose, selecting components, analyzing interactions, and assessing interventions. We highlight insights for researchers interested in assessing the implementation of system-wide sustainability strategies, with a focus on human well-being as an overarching objective, including methods that incorporate nature-society interactions into sectoral decision-support models, simulating cross-sector connections and differing contexts, and implementing computational and statistical approaches that evaluate decision scenarios under uncertainty. We additionally highlight techniques that can serve to foreground issues of power differentials among actors, including methods that can capture diverse societal actions and their agency, and incorporate different perspectives and normative visions. As a concrete example of the utility of a set of methods and advances from this survey of coupled nature-society systems modeling, we show how advances in computational techniques can be used to assess the degree to which national-scale climate policies in the United States can impact air pollution exposure to different racial/ethnic groups. 

How to cite: Selin, N., Giang, A., and Clark, W.: Modeling Dynamic Systems for Sustainable Development , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15327, https://doi.org/10.5194/egusphere-egu24-15327, 2024.

EGU24-15637 | ECS | Orals | ITS3.27/ERE6.6 | Highlight

Global convergence of incomes in a climate-constrained world 

Yannick Oswald

Sustainable development aims for equal living standards in the Global North and Global South while limiting global warming as much as possible. If measured in monetary terms, it is well known that eradicating extreme poverty (so lifting people beyond $PPP 2.15 consumption expenditure per capita (pc) per day) does not threaten climate goals. However, just beyond extreme poverty is not an acceptable goal for the living standards of people. In Europe, for instance, people live between $PPP 30pc and $PPP 70pc on average depending on the country. Moreover, some research has shown that lifting all people globally to only $PPP 5.5pc per day already implies allocating a much bigger carbon budget share for poverty eradication given current techno-economic parameters. Hence, if global poverty is to be reduced substantially, high-income nations and groups require a more rapid reduction of emissions so that global climate goals remain met. Therefore, in this research, I explore global convergence scenarios of incomes, taking between-country inequality and within-country inequality into account. I do so based on data from the World Inequality Lab and consider the following constraints and parameters: (i) income level towards which countries and groups converge (e.g. $PPP 30pc consumption expenditure a day or $PPP 50pc and so forth) (ii) carbon budgets, (iii) time horizon (for example whether convergence happens until 2050, 2075 or 2100 and so forth) and (iv) technology evolution (the pace of carbon intensity reduction). By studying the trade-offs between these, I elaborate on possible growth pathways for low-income countries and low-income groups world-wide, and corresponding degrowth or steady-state pathways in Global North countries and high-income groups world-wide. I find, for example, that, if all high-income nations continue historic growth trajectories while low- and middle-income countries converge to an acceptably high level of income, strict carbon budgets are difficult to maintain and hence high-income countries might consider steady-state or degrowth trajectories to free up “growth space” in low-income countries. The results may inform country-specific and income-group specific climate-economic scenarios in integrated assessment models and the wider policy debate.   

How to cite: Oswald, Y.: Global convergence of incomes in a climate-constrained world, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15637, https://doi.org/10.5194/egusphere-egu24-15637, 2024.

EGU24-17982 | ECS | Orals | ITS3.27/ERE6.6

Heat-related mortality projections for 335 European NUTs3 regions 

Ane Loroño Leturiondo, Anil Markandya, and Elisa Sainz de Murieta

Under climate change, heat waves are expected to become more frequent, more intense, and longer representing a risk factor in mortality and morbidity and a significant threat to public health [1]. In this study, we have performed a mortality impact assessment due to heat in European regions estimating the number of deaths related to mortality in each European country.

Our dataset includes the relative risk of death related to high-temperature data, as well as baseline mortality (2013) and projections (2030, 2050, and 2070) for adults over 65 years. We have calculated the number of deaths attributed to heat using the World Health Organization (WHO) relative risk model [2]. Adaptation was partly incorporated into the assessment by adjusting the optimum temperature in future periods under 4 combinations of climate and socioeconomic scenarios (RCP2.6-SSP1, RCP4.5-SSP2, RCP7.0-SSP3 and RCP8.5-SSP5) based on the latest CMIP6 data.

Preliminary results show that heat-related risk and the number of deaths increase with time, as expected. In the short term (2030), the increase in mortality measured as the ratio between projected and baseline mortality, does not change much across scenarios. The average rate of daily deaths for the EU27 is 2.054 (1.766,2.354) under SSP1-2.6 (the central estimate is the median, and percentiles 10 and 90 have been used for the interval), and 2.244 (1.853,2.694) in SSP5-8.5. Mortality increases over time, although it varies greatly depending on the scenario considered. By 2070 the number of fatalities reach 3.529 (2.849,4.88) in SSP1-2.6 and 7.658 (5.984,10.07) in SSP5-8.5. We also find significant differences across countries. By 2070, under a middle-row scenario (SSP2-4.5), countries such as Belgium, Bulgaria, Czechia, Denmark, Germany, Estonia, Croatia, Latvia, Lithuania, Finland, and Sweden present an increase in mortality between 2 and 3 fold baseline mortality. Others, mostly in Southern Europe such as Greece, France, Malta, Italy or Cyprus, but also Luxemburg and Slovenia, have a severe increase in mortality, 5 to 9 times baseline mortality.

We also estimated the annual number of deaths in the EU27 due to extreme heat. In the baseline, our results are 72,955 annual deaths, which exceeds previous estimates, such as that obtained for the summer of 2022 [6], but this difference could be linked to the use of more recent CMIP6 data. In 2070, the number of heat-induced deaths in the EU could reach 211.039 (140.686,293.409) in SSP1-2.6 and 435.331 (283.927,671.089) in SSP5-8.5. Some studies [3] show that, under RCP8.5, annual mortality will possibly increase by up to 300,000 excess deaths by the last quarter of the 21st century, accounting for exposures above the minimum mortality temperature, including extremely hot temperatures, so our figures do not differ much of these estimates, even though they are higher than some others [4, 5].

 

 

How to cite: Loroño Leturiondo, A., Markandya, A., and Sainz de Murieta, E.: Heat-related mortality projections for 335 European NUTs3 regions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17982, https://doi.org/10.5194/egusphere-egu24-17982, 2024.

EGU24-19615 | Posters on site | ITS3.27/ERE6.6

Passenger transport decarbonisation under different equity considerations 

Dirk-Jan Van de Ven and Jon Sampedro

Climate change is often seen as an equity problem, as it is caused primarily by richer countries and households, while its impacts are generally expected to affect poorer countries and households significantly stronger. Climate policy aiming at mitigating these impacts, however, can also have a regressive impact on societies, unless it is designed such that the costs of mitigation are shared progressively depending on wealth differences. At the same time, historical energy transitions have often been driven by wealthy consumers demanding higher quality goods and services, which consequently grew from niche to mainstream technologies. Particularly the transportation sector is a sector difficult to decarbonise, while there are significant differences in contribution between poorer and wealthier users. This study uses a global integrated assessment model (GCAM) with 10 different income groups for each of the 32 regions to compare several decarbonisation scenarios for passenger transportation. On the one hand, implementing a general cap-and-trade policy for transport emissions, while traditionally seen as the economically optimal policy, affects poorer individuals significantly more in terms of access to transport services in a decarbonised world. On the other hand, implementing fixed caps for each country and income group, which cannot be traded with consumers at lower other income groups or countries, and are globally equal for each individual, leads to significantly higher costs for higher income individuals, but does not affect the access to transport services of poorer individuals as strongly. Also, this last alternative leads to a significantly faster take-up of modern clean technologies in transport.

How to cite: Van de Ven, D.-J. and Sampedro, J.: Passenger transport decarbonisation under different equity considerations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19615, https://doi.org/10.5194/egusphere-egu24-19615, 2024.

EGU24-21164 | Orals | ITS3.27/ERE6.6

Themes and Recommendations from Pacific Northwest National Laboratory’s Human Well-being Workshop 

Stephanie Waldhoff, Brian O'Neill, James Edmonds, and Bethel Tarekegne

Human well-being has been defined as an inherently multidimensional concept that broadly refers to what constitutes the “good life”. Stiglitz et al. (2009). Well-being cannot be described with a single number. Rather, it requires a wide range of measures of the state of human outcomes. Taken together, these can provide a description of well-being and to better guide decision making.

Here we summarize a set of interdisciplinary conversations that occurred during the course of a two-day, in-person workshop convened by PNNL September 27-28, 2023 in College Park, Maryland, which laid the foundations for a new field of well-being science and application. Here we share a summary of the key themes and recommendations from this workshop.

Themes

The Science of Human Well-being: Understanding well-being requires assembling both quantitative and qualitative data at multiple scales in time, space, and other dimensions, identifying and articulating relationships using tools and techniques drawing from multiple disciplines and applying them to both understand the past and explore the consequences of alternative decisions for the future. Participants identified specific challenges with current model capabilities, data, incorporating qualitative information, metrics, and scenarios.

Applications of Human Well-being Research: The goal of developing a scientific understanding of well-being is to have tools that can inform decisions. Applying the tools of well-being science has two distinct benefits. First, the multi-dimensional, multi-disciplinary tools and data enable better decisions. In addition, the use of well-being science to inform decisions can improve the direction of research and its quality. Participants identified challenges with connecting decision makers and researchers and with policy design and implementation.

Communication of Human Well-being Outcomes: Well-being science needs to communicate across the full spectrum of stakeholders, decision makers, and researchers. The interdisciplinary nature of well-being science results in a language barrier that needs to be overcome within the well-being science community and with stakeholders. Participants discussed challenges with identifying the “correct” stakeholders and communication across all of these groups.

Recommendations

Establish a new field of human well-being science and research: Opportunities for improving communication include (1) developing a Community of Practice on human well-being for researchers and policy makers from different academic and policy domains, (2) holding additional workshops to connect researchers and end users, and (3) writing a commentary piece for an academic journal describing the need for this type of research.

Develop and communicate human well-being applications for decision-making: A primary need identified is for significant model developments and research, as there is currently a mismatch between the types of questions being asked by decision makers and the ability to model those outcomes.

Develop long-term, sustainable funding to support this multi-disciplinary, multi-scale research: The most important recommendation was to increase funding for research and model development. Without this funding, researchers will not be able to provide the analyses and results that decision makers need to account for aspects of equity and justice in their decisions.

 Reference: Stiglitz, J. E., Sen, A., & Fitoussi, J.-P. (2009). Report of the Commission on the Measurement of Economic Performance and Social Progress https://ec.europa.eu/eurostat/documents/8131721/8131772/Stiglitz-Sen-Fitoussi-Commission-report.pdf

How to cite: Waldhoff, S., O'Neill, B., Edmonds, J., and Tarekegne, B.: Themes and Recommendations from Pacific Northwest National Laboratory’s Human Well-being Workshop, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21164, https://doi.org/10.5194/egusphere-egu24-21164, 2024.

EGU24-21402 | ECS | Orals | ITS3.27/ERE6.6

Analyzing energy security outcomes of decarbonization across income groups in GCAM-USA 

Kelly Casper, Ying Zhang, Stephanie Waldhoff, and Brian O'Neill

The equity implications brought on by climate change and the actions taken in response are a growing area of interest. Such implications are important for the design and implementation of transformative policies but are understudied at subnational levels, especially with considerations to impacts on human well-being. Specifically, integrated assessment models (IAMs), the primary tools for evaluating these policies and their implications, have advanced science and policymaking but lack detailed subnational information. In this study, we developed projections of U.S. state-level income distributions (Casper et al., 2023), represented by income deciles, and incorporated those projections into an IAM (GCAM-USA) to examine the effects of decarbonization policies on residential energy security, a key aspect of human well-being, across ten income groups in each state. Importantly, our projections of residential energy security include several metrics in order to represent the multi-faceted nature of energy security and to explore tradeoffs that consumers at different income levels may need to make in response to changing energy prices. Specifically, we estimate energy service consumption, the satiation gap, and energy burden for each decile. Our study identifies unequal impacts across groups, with the most significant impact observed among mid-to-low income groups. In 2050, the projected energy burden is lower than in 2020 due to the projected increase in income over time relative to changes in energy service prices. However, the lowest income group in most states still experiences ‘high’ energy burden in 2050 under business-as-usual, while the decarbonization policies leads to even higher energy burden for the lowest income group (households spending additional 0.6% out of income for residential energy services).With the lowest income groups experiencing worse outcomes, this work suggests that targeted policy interventions that consider the impacts on different groups will promote more equitable transitions to a net-zero greenhouse gas emissions economy. The results focus solely on the impacts of decarbonization policies on residential energy security metrics, excluding other potential positive effects on human well-being like reductions in air pollution.

References

Casper, K. C., Narayan, K. B., O’Neill, B. C., Waldhoff, S. T., Zhang, Y., & Wejnert-Depue, C. P. (2023). Non-parametric projections of the net-income distribution for all U.S. states for the Shared Socioeconomic Pathways. Environmental Research Letters, 18(11), 114001. https://doi.org/10.1088/1748-9326/acf9b8

How to cite: Casper, K., Zhang, Y., Waldhoff, S., and O'Neill, B.: Analyzing energy security outcomes of decarbonization across income groups in GCAM-USA, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21402, https://doi.org/10.5194/egusphere-egu24-21402, 2024.

EGU24-1315 | ECS | PICO | ITS1.14/ERE6.11

Soil data quality and resolution matter when predicting woody plant species in temperate forests 

Francesco Rota, Daniel Scherrer, Ariel Bergamini, Bronwyn Price, Lorenz Walthert, and Andri Baltensweiler

Soil properties influence plant physiology and growth, playing a fundamental role in shaping species niches in forest ecosystems. Here, we investigated the impact of soil data quality on the performance of climate-topography species distribution models (SDMs) of temperate forest woody plants. We compared models based on measured soil properties with those based on digitally mapped soil properties at different spatial resolutions (25m and 250m). We first calibrated SDMs with measured soil data and plant species presences and absences from plots in mature temperate forest stands. Then, we developed models using the same soil predictors, but extracted from digital soil maps at the nearest neighbouring plots of the Swiss National Forestry Inventory. Our approach enabled a comprehensive assessment of the significance of soil data quality for 41 Swiss forest woody plant species. The predictive power of SDMs without soil information compared to those with soil information, as well as those with measured vs digitally mapped soil information at different spatial resolutions was evaluated with metrics of model performance and variable contribution. On average, performance of models with measured and digitally mapped soil properties was significantly improved over those without soil information. SDMs based on measured and high-resolution soil maps showed a higher performance, especially for species with an ‘extreme’ niche position (e.g. preference for high or low pH), compared to those using coarse-resolution (250m) soil information. Nevertheless, globally available soil maps can provide important predictors if no high-resolution soil maps are available. Moreover, among the tested soil predictors,  pH and clay content of the topsoil layers improved the predictive power of SDMs for forest woody plants the most. Such improved model performance informs biodiversity modelling about the relevance of soil data quality in SDMs for species of temperate forest ecosystems. In conclusion, the incorporation of accurate soil information into SDMs becomes indispensable for making well-informed forecasts for guiding decisions in forest management, also when addressing the potential distribution shifts of woody plant species due to climate change.

How to cite: Rota, F., Scherrer, D., Bergamini, A., Price, B., Walthert, L., and Baltensweiler, A.: Soil data quality and resolution matter when predicting woody plant species in temperate forests, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1315, https://doi.org/10.5194/egusphere-egu24-1315, 2024.

EGU24-2788 | PICO | ITS1.14/ERE6.11 | Highlight

Altitudinal shifting of major forest tree species in Italian mountains under climate change 

Sergio Noce, Cristina Cipriano, and Monia Santini

Climate change has profound implications for global ecosystems, particularly in mountainous regions where species distribution and composition are highly sensitive to changing environmental conditions. Understanding the potential impacts of climate change on native forest species is crucial for effective conservation and management strategies. Despite numerous studies on climate change impacts, there remains a need to investigate the future dynamics of climate suitability for key native forest species, especially in specific mountainous sections. This study aims to address this knowledge gap by examining the potential shifts in altitudinal range and suitability for forest species in Italy's mountainous regions. By using species distribution models, through MaxEnt we show the divergent impacts among species and scenarios, with most species experiencing a contraction in their altitudinal range of suitability whereas others show the potential to extend beyond the current tree line. The Northern and North-Eastern Apennines exhibit the greatest and most widespread impacts on all species, emphasizing their vulnerability. Our findings highlight the complex and dynamic nature of climate change impacts on forest species in Italy. While most species are projected to experience a contraction in their altitudinal range, the European larch in the Alpine region and the Turkey oak in the Apennines show potential gains and could play significant roles in maintaining wooded populations. The tree line is generally expected to shift upward, impacting the European beech, a keystone species in the Italian mountain environment, negatively in the Alpine arc and Northern Apennines, while showing good future suitability above 1,500 meters in the Central and Southern Apennines. Instead, the Maritime pine emerges as a promising candidate for the future of the Southern Apennines. The projected impacts on mountain biodiversity, particularly in terms of forest population composition, suggest the need for comprehensive conservation and management strategies. The study emphasizes the importance of using high-resolution climate data and considering multiple factors and scenarios when assessing species vulnerability. The findings have implications at the local, regional, and national levels, emphasizing the need for continued efforts in producing reliable datasets and forecasts to inform targeted conservation efforts and adaptive management strategies in the face of climate change.

How to cite: Noce, S., Cipriano, C., and Santini, M.: Altitudinal shifting of major forest tree species in Italian mountains under climate change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2788, https://doi.org/10.5194/egusphere-egu24-2788, 2024.

EGU24-3570 | PICO | ITS1.14/ERE6.11 | Highlight

Future Forest: A Decision Support System for Smart and Sustainable Forest Management. 

Flaminia Catalli, Fabian Faßnacht, Jonas Kerber, Jonathan Költzow, Johannes Mohr, Werner Rammer, Thorsten Reitz, and Christopher Schiller

Future Forest is an “AI Lighthouse” project funded by the German Ministry of the Environment that has two main objectives: develop a decision support system for forest management and build the foundations for a forest transformation data space.

The Future Forest decision support system is based on a chain of AI/numerical models. The information used to analyse the best alternatives in an area of interest comes from state-of-the-art process-based forest simulations of specific forest management scenarios, AI-based upscaling techniques, and remotely sensed data on current forest composition and health. This data will cover Germany’s forests wall-to-wall with an unprecedented resolution of 100m for the management scenarios and climate data, and up to 10m for other variables.

Creating such a system is impossible without having an accessible pool of data. Since much of the needed information is not freely available, data is collected and organized as an IDSA-compliant data space. Such a data space serves as a platform where various data holders and users converge, exchanging information and analytical applications within a structured data governance framework. This arrangement empowers platform users to retain comprehensive control over their data and enables them to share information with third parties in a controlled and secure environment.

 

Future Forest is one year away from completion, and we can now present the first results on our way towards a forest management 2.0 system. This system is designed to offer a spectrum of alternatives for effectively managing local forest stands in response to climate change. Considering the forest owner's management objectives, such as timber production or biodiversity, the system proposes alternatives using various ecosystem indicators, encompassing wood production, carbon storage, and biodiversity considerations. The final ranking of the alternatives is based on a multi-criteria decision analysis algorithm, which incorporates also a comprehensive robustness and sensitivity analysis.

In this contribution, we outline the tools utilized to make informed decisions, from the neuronal networks for forest classification to the forest dynamic simulations, and the decision support system. We discuss the constraints encountered and highlight the innovations incorporated in each of these tools. We will discuss the attempt made to offer an explainable or even interpretable model, as far as this was possible. 

How to cite: Catalli, F., Faßnacht, F., Kerber, J., Költzow, J., Mohr, J., Rammer, W., Reitz, T., and Schiller, C.: Future Forest: A Decision Support System for Smart and Sustainable Forest Management., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3570, https://doi.org/10.5194/egusphere-egu24-3570, 2024.

EGU24-5097 | ECS | PICO | ITS1.14/ERE6.11 | Highlight

Development of continuous cover forests under different levels of global warming – a methodological case study in Southern Germany 

Marc Djahangard, Maximiliano Costa, Harald Bugmann, and Rasoul Yousefpour

Informing forest decision makers about the impacts of climate change on forests is challenging because the representative concentration pathway scenarios (RCPs) impose deep uncertainty and complexity that is difficult to integrate in management planning. A user-oriented translation of the RCPs would facilitate the integration of climate change impacts in forest decisions and improve the understanding of how different climate policy actions would affect forests.

We applied a translation of the RCPs by analyzing how three global warming scenarios related to climate policy actions – the Paris targets (1.5°C and 2°C warming) and a higher warming level without climate policy (3°C) – would impact forest dynamics. We developed indices of forest processes (e.g., species succession, biomass, harvest) that capture changes induced by the global warming scenarios relative to a reference period (1981 – 2010). The methodology was adapted from the JRC PESETA IV project, where climate indices had been developed and impacts on forest vulnerability was explored.

We applied this method with a large-scale forest model (LandClim) on a complex and highly diverse 5000 ha forest landscape over an elevation gradient from lowland deciduous to high montane conifer forests in the area of Freiburg, Southern Germany. Simulations started from the state of the forest in the year 2010, and both no-management and a business-as-usual management (BAU) was simulated. For the initial state of the forest, we applied a state-of-the-art initialization procedure that makes use of a detailed inventory network (over 2000 inventory points in the study area) to depict the current forest conditions (e.g., species distribution, stem numbers, tree ages, stem diameters at breast height) at high resolution. BAU was applied in the form of close-to-nature management based on the guidelines by the State Forestry Department. It includes >10 forest types with both younger and older stands.

Simulation results indicate reductions of biomass and species richness at lower elevations, including both lowland and submontane zones, connected to an upslope shift of species. As these changes intensify with increasing global warming, the largest impacts are observed under the 3°C warming scenario, leading to the loss of biodiversity associated with dominant species capitalizing on the changing ecological conditions.

In summary, by applying this method for a diversity in continuous cover forests over a large elevation gradient, our study outlines important forest dynamics representative for temperate forests in Central Europe under three global warming scenarios. Moreover, the evaluation of close-to-nature management can give important insights for forest decision making.

How to cite: Djahangard, M., Costa, M., Bugmann, H., and Yousefpour, R.: Development of continuous cover forests under different levels of global warming – a methodological case study in Southern Germany, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5097, https://doi.org/10.5194/egusphere-egu24-5097, 2024.

Boreal forests play an important role in climate change mitigation, biodiversity conservation and the provision of vital ecosystem services. Changing climate is likely to increase the frequency and the severity of forest disturbances. Hence, increasing disturbances may offset the past and ongoing efforts to increase forest-based mitigation and halt biodiversity loss. Therefore, understanding the dynamics of forest ecosystems and predicting their responses to management, changing climate and disturbance regimes is vital.  While forest disturbance risk prevention measures i.e., adaptive management, offer solutions to safeguard future timber yields, the effects of adaptive management on biodiversity, climate change mitigation potential of forests and other ecosystem services have received little attention. In addition, it remains unknown whether climate change alters disturbance regimes in a way that cancels out efforts to increase and preserve carbon stocks and protect forest biodiversity. In this study we contrast the effects of mitigation versus adaptation forest management on the resilience of boreal forest ecosystems in a changing climate. We address the following questions: i) How timber harvests, forest carbon stocks and disturbed volumes develop in different forest management and land-use options that emphasize either adaptation or mitigation under different climate scenarios? ii) What are the synergies and trade-offs in ecosystem service and biodiversity indicators in adaptation and mitigation options? To address these questions, we used the process-based forest landscape and disturbance model iLand to dynamically simulate interactions of forest management, climate change and disturbances. We simulated combinations of seven forest management scenarios and three climate scenarios with ten replicate runs for 80 years in Finland. The forest management scenarios included a business-as-usual scenario and mitigation and adaptation scenarios with changes in rotation lengths and in the shares of deciduous trees in regeneration. Mitigation managements resulted in on average 6 to 15% higher carbon stocks over the simulation period compared to business-as-usual even when disturbances were accounted for but even halved the annual harvests. Mitigation management generally increased the amount of deadwood (3-21%) and large diameter trees (10-52%) compared to business-as-usual management but the severity of climate change reduced the positive trend on large diameter trees. Adaptive management reduced especially the bark beetle disturbances but, in some cases, the disturbed volumes were even higher than business-as-usual management because of increased wind damages. Generally, over the simulation period, adaptive management had a small positive impact on deadwood and mixed effects on large diameter trees.  Scenic beauty was impacted very little by climate change or management. Our findings highlight the complex interactions between disturbance risk prevention, biodiversity, carbon storage and sequestration and other ecosystem services. The results help to guide forest managers and policymakers in planning conservation and mitigation efforts, maximizing multiple benefits and enhancing forest resilience under a changing climate.

How to cite: Repo, A., Albrich, K., Jantunen, A., Aalto, J., Lehtonen, I., and Honkaniemi, J.: Contrasting mitigation and adaptation forest management strategies: unraveling the effects on biodiversity and ecosystem services in changing climate and disturbance regimes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8520, https://doi.org/10.5194/egusphere-egu24-8520, 2024.

EGU24-8664 | ECS | PICO | ITS1.14/ERE6.11

Stand age diversity affects forests' resilience and stability, although unevenly. 

Elia Vangi, Daniela Dalmonech, Elisa Cioccolo, Gina Marano, Leonardo Bianchini, Paulina Puchi, Elisa Grieco, Alessandro Cescatti, Gherardo Chirici, and Alessio Collalti

Tree age plays an essential role in forest ecosystems' functioning by affecting structural and physiological plant traits that modulate the water and carbon budgets. On the other hand, tree age distribution in forests depends on population dynamics and, therefore, on the balance between tree mortality and regeneration events, which are ultimately controlled by natural and anthropogenic disturbances. Therefore, the human-induced modulation of the tree age distribution in forests represents a significant and not fully explored pathway to optimize the stability and resilience of forests.

To examine the influence of age distribution on the stability and resilience of forest carbon budget under current and future climate conditions, we applied a biogeochemically process-based model to three past-managed forest stands and modeled their stability and resilience in terms of Net Primary Production (NPP) in the future as undisturbed systems. The model was forced with climate outputs of five Earth System Models under four representative climate scenarios plus one baseline climate scenario over a matrix of 11 age classes for each forest. We found that the NPP peak was reached in the young and middle-aged class (16- to 50-year-old) regardless of the climate scenario, as ecological theories postulate. Under climate change scenarios, the beech forest showed an increasing NPP as well as stability with increasing atmospheric CO2 and temperature across all age classes, while resilience remained stable. Conversely, in the spruce and Scots pine-dominated sites, NPP decreased under climate change scenarios. In coniferous stands, stability and resilience seem to be controlled mainly by age rather than the climate, with the older stands being more stable and resilient under all scenarios.

These findings highlight the importance of considering age classes and species-specific responses when assessing the impacts of climate change on forest stability and resilience, calling for tailored management strategies to enhance the adaptability of forests in the face of changing climatic conditions, reflecting the different species and age-dependent responses to climate.

How to cite: Vangi, E., Dalmonech, D., Cioccolo, E., Marano, G., Bianchini, L., Puchi, P., Grieco, E., Cescatti, A., Chirici, G., and Collalti, A.: Stand age diversity affects forests' resilience and stability, although unevenly., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8664, https://doi.org/10.5194/egusphere-egu24-8664, 2024.

EGU24-9634 | PICO | ITS1.14/ERE6.11

Incorporating nitrogen effects in a management and environment sensitive forest model at regional scale 

Annikki Mäkelä, Francesco Minunno, Ritika Srinet, and Mikko Peltoniemi

Regional and national level projections of forest growth, productivity and carbon sequestration are in high demand for policy makers to understand the impacts of climate change and forest management on ecosystem services. The rapid environmental change has accentuated the need of environmentally sensitive forest models that are simultaneously capable of simulating the development of forests under different management regimes and from an initial state defined in terms of standard forest mensuration variables. Efforts to make environmentally sensitive process models more management oriented have been supported by recent developments in model-data assimilation, allowing for quantitatively reliable, policy-relevant projections. However, while the processes related to forest C balance are quite well understood, possible future changes of nitrogen availability still remain a challenge for modelling, as empirical results are few and theories have not converged to a consensus. This is particularly important for the boreal zone where forests are generally regarded as N limited.

PREBAS is a management-sensitive carbon-balance model that has been calibrated to forest mensuration type data in Finland. In the calibration, N availability was assumed to be derivable from empirical site quality classification. Following empirical observations and predictions from theoretical models, site quality influences fine-root foliage ratio and stand carrying capacity in PREBAS. The model has been linked with a soil C balance model, Yasso. The combined model incorporates environmental impacts on photosynthesis, respiration, litter fall and soil organic matter decomposition. The model system has been found to produce a spatial distribution of national forest growth and C balance levels in Finland that are well comparable with forest statistics and the Finnish national greenhouse gas inventory, and it has also been evaluated more widely in Northern Europe.

The objective of this study was to examine the implications of different future N availabilities on PREBAS projections under climate change. For this, we carried out simulations in a set of 35 sites across a climatic transect and with variable site quality. For these sites we first estimated stand nitrogen requirement on the basis of growth, litter fall and tissue N concentration under maximum canopy cover and in current climate. We then postulated that N uptake depends on N availability and fine root biomass, and estimated N availability by demanding that N uptake should match the N requirement. Based on the results, we developed a method for estimating carrying capacity and below-ground allocation on the basis of changes in the relative availabilities of carbon and nitrogen.

We tested the method by simulating growth in a hypothetical FACE experiment, which showed results qualitatively consistent with the literature of ectomycorrhiza-dominated forests. We then compared three different assumptions of changing nitrogen availability under climate change: 1) no change, 2) change is derivable from changing SOM decomposition rate, and 3) N availability increases in pace with N requirement. These were applied in country-wide simulations under different climate scenarios. The plausibility of the scenarios and results are discussed in the light of previous literature.

 

How to cite: Mäkelä, A., Minunno, F., Srinet, R., and Peltoniemi, M.: Incorporating nitrogen effects in a management and environment sensitive forest model at regional scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9634, https://doi.org/10.5194/egusphere-egu24-9634, 2024.

EGU24-9929 | ECS | PICO | ITS1.14/ERE6.11

Realistic representation of forest harvesting for large-scale models – integrating harvest information from national forest inventories to LPJ-GUESS 

Susanne Suvanto, Mats Lindeskog, Stefan Olin, Karl Piltz, and Thomas A. M. Pugh

Harvesting of wood is one of the key processes of forest management, strongly impacting the structure and dynamics of European forests. This makes accounting for it crucial in any large-scale analysis of forest ecosystems. Yet, the representation of forest harvests in large-scale models is typically far from realistic, as the actual management regimes are not well described by simple rules or even by formal management guidelines.

Here, we show an implementation of national forest inventory (NFI) -based forest harvesting regimes in a demographic vegetation model, LPJ-GUESS. In our approach, the probability of harvest in the model simulation is based on frequency of harvest events in the NFI data in forests with similar structure and geospatial location. Similarly, the characteristics of the harvest event (the percentage of the removed tree basal area and, in case of partial harvests, the tree size targeted in the harvest) are based on the observed harvest events in the data, and depend in the simulation on forest structure and location. This means that model simulations are dynamic, responding to the real state of the forest. We demonstrate this with several countries in Europe, for which we have earlier created NFI-based harvest regimes based on analysis of more than 180 000 forest plots. Forests are simulated with LPJ-GUESS with different forest harvesting set-ups, allowing us to compare the outcome of the suggested NFI-based harvest implementation to other approaches, including simplified clear-cut rules and density-based thinning (based on Reineke’s rule). In addition, the simulation results are compared to observational evaluation data.

Moving from simple rule-based approaches to observed NFI-based harvest regimes can bring the model simulations closer to how forests are actually currently managed. Our approach blending big data and dynamics modelling has potential to both enable improved assessments of continental-scale carbon dynamics and provide a realistic reference to which potential future forest management changes can be compared to.

How to cite: Suvanto, S., Lindeskog, M., Olin, S., Piltz, K., and Pugh, T. A. M.: Realistic representation of forest harvesting for large-scale models – integrating harvest information from national forest inventories to LPJ-GUESS, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9929, https://doi.org/10.5194/egusphere-egu24-9929, 2024.

EGU24-15673 | ECS | PICO | ITS1.14/ERE6.11

Evaluating the UK forest demography and carbon cycle using a process-based Land Surface Model, JULES-RED 

Hsi-Kai Chou, Anna Harper, Arthur Argles, Carolina Duran-Rojas, Emma Littleton, and Peter Cox

Global warming and climate change caused by greenhouse gas (GHG) emission is projected to have multiple impacts on the forest ecosystems. To mitigate these impacts, the UK Government has set a goal of net zero emissions of GHG by 2050. One core strategy is to use afforestation and forestry management to implement large-scale Greenhouse Gas Removal (GGR). However, the effectiveness of afforestation as a GGR strategy is difficult to fully evaluate with standard empirical models due to the complexities of environmental conditions under a changing climate. Alternatively, process-based land surface models (LSM), such as the Joint UK Land Environment Simulator (JULES), are increasingly being used to evaluate forest growth within a national GGR context as they are driven by environmental drivers. By coupling the Robust Ecosystem Demography (RED) model with JULES, we model the forest dynamic and carbon sequestration among a set of Representative Concentration Pathway (RCP) projections geographically across the UK up to 2080. Our results demonstrate the capability of mapping the potential GGR across the UK while also accounting for the changing environment and risks of climate change. The results show that JULES-RED can provide an effective tool for national-scale afforestation evaluation toward the 2050 net-zero targets.

How to cite: Chou, H.-K., Harper, A., Argles, A., Duran-Rojas, C., Littleton, E., and Cox, P.: Evaluating the UK forest demography and carbon cycle using a process-based Land Surface Model, JULES-RED, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15673, https://doi.org/10.5194/egusphere-egu24-15673, 2024.

EGU24-16274 | ECS | PICO | ITS1.14/ERE6.11 | Highlight

Predicting trajectories of temperate forest understorey vegetation responses to global change 

Bingbin Wen and the forestREplot and PASTFORWARD

Predicting forest understorey community responses to global change and forest management is vital given the importance of the understorey for biodiversity conservation and forest functioning. Though substantial effort has gone into disentangling how global change will impact the understorey community, the scarcity of information on site-specific environmental drivers together with large temporal and spatial drivers has limited our understanding of how global change drivers affect understorey characteristics at specific forest sites. Here, using understorey resurvey data collected from 1363 plots across temperate Europe and applying a machine learning approach, we used Gradient Boosting Regression Models (GBM) to model and predict trajectories of four understorey characteristics (species richness, total understorey vegetation cover, proportion of woody species and proportion of forest specialists) to global-change and site-specific drivers (e.g. soil, overstory conditions). We applied the final GBM models to 8 forest sites in Austria to evaluate the effect of future scenarios for nitrogen deposition, climate change and forest management on the forest understory in the year 2030, and project the trajectory of understorey properties from year 1993 to 2030.  The trajectory results showed that increasing nitrogen deposition decreased species richness and proportion of woody species, but increased total understorey vegetation cover and proportion of forest specialists. The effect of climate warming on the proportion of forest specialists appeared to be limited but led to a decrease in species richness, total vegetation cover and proportion of woody species. Finally, a closed canopy could shift the community towards more woody species and forest specialists but may lower species richness and total vegetation cover. Our presented model allows the prediction of trajectories of understorey vegetation responses to global change and management interventions at specific forest sites. 

How to cite: Wen, B. and the forestREplot and PASTFORWARD: Predicting trajectories of temperate forest understorey vegetation responses to global change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16274, https://doi.org/10.5194/egusphere-egu24-16274, 2024.

EGU24-17088 | ECS | PICO | ITS1.14/ERE6.11

Modelling water balance components in a temperate forest in Germany: A comparative analysis of pine, oak, and beech 

Angela Morales-Santos, Michael Köhler, Stefan Fleck, Birte Scheler, Markus Wagner, and Henning Meesenburg

Understanding the water balance components in forests is crucial for sustainable land and water management. The Frankfurt Rhine-Main metropolitan region in Germany is heavily dependent on groundwater, with the Hessian Ried forest being one of the main sources. However, climate change, population growth, continuous land sealing, and the expansion of farmland and irrigation in the region, have increased the pressure on water resources, exacerbating conflicts over water use between the affected sectors. Therefore, the region requires comprehensive solutions for a sustainable and flexible water management.

This study focuses on modelling the water balance components in three monitoring plots located in the Hessian Ried. Each plot is dominated by a different tree species — pine, oak, and beech. The aim of the study is to assess the impact of tree species and soil physical properties on water dynamics and availability. We employed the LWF-Brook90R package for the implementation of the LWF-Brook90 model considering climatic boundary conditions, vegetation parameters and soil physical parameters at different depths. The study covers the period of 2005 to 2023 allowing the assessment of seasonal variations over several years. Moreover, we performed the assessment of different parameter sets and a Bayesian calibration in order to analyse the variations in the resulting water balance components for each plot. We compared our simulations to throughfall and soil water content observations.

Our findings revealed complex interplays between tree species and water balance components, highlighting the importance of species-specific considerations when modelling forests. We obtained a good agreement between our results and observed throughfall, indicated by an R2 ≥ 0.7. The different parameter sets and the calibration delivered highly similar statistical indicators of observed versus simulated throughfall. However, the calibration did not improve the throughfall simulations in all cases. Regarding actual transpiration and interception rates, the pine plot exhibited larger variations depending on the parameter set used, compared to oak and beech. Both deciduous stands presented a larger transpiration deficit as water stress indicator compared to the pine plot. The transpiration deficit increased considerably in the three plots after calibrating interception and soil physical parameters, compared to default datasets. Additionally, the simulations of the pine plot resulted in the lowest drainage rates among the plots, due to a combination of factors including the evergreen canopy and predominant sandy soil texture along the entire rooting depth. We achieved a more comprehensive and improved estimation of the soil water content — and consequently soil water storage in the root zone — after calibrating the soil physical parameters in contrast to pre-established soil datasets. This allowed for uncertainties in the estimation of soil water content in the unsaturated zone, which is a key consideration when modelling water balance components.

The insights gained from this research have implications for climate change adaptation and mitigation. As climate patterns shift, understanding how different tree species influence water availability and utilization becomes paramount. The presented models serve as a valuable tool for predicting and managing water resources in diverse forested landscapes, supporting the development of adaptive strategies for sustainable forest management.

How to cite: Morales-Santos, A., Köhler, M., Fleck, S., Scheler, B., Wagner, M., and Meesenburg, H.: Modelling water balance components in a temperate forest in Germany: A comparative analysis of pine, oak, and beech, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17088, https://doi.org/10.5194/egusphere-egu24-17088, 2024.

Forest ecosystems play a well established role in providing a multitude of ecosystem services. It is imperative to maintain the health of forests to ensure a continuous supply of these services. However, increasing pressures such as growing demand of wood products and forest overexploitation, climate change, land use change, etc. are compromising their resilience and services provision.
To address this challenge, various European and national policies are directed on either expanding natural and unmanaged forests (e.g. EU Biodiversity Strategy; European Climate Law ) or improving forest management practices (e. EU Forest Strategy, EU Bioeconomy Strategy). In the former case, the goal is to contain or exclude direct and indirect human intervention and disturbances. In the latter case, while human presence and management are allowed, they must adhere to sustainable and respectful practices
The burden to provide a better balanced array of ecosystem services, ensuring the maintenance of forest resilience in the future, falls largely on the shoulders of forest owners and managers who will face opportunity costs and a deviation from their profit maximization objective.
Nevertheless, achieving policy targets will be made more efficient and realistic with an active involvement of the entire community in a collective endeavour. Individuals may be encouraged and required to contribute to mitigating private economic effort by acknowledging the economic value of market and non market ecosystem services other than provisioning and facilitating payments for these services through a mechanism commonly referred as payments for ecosystem services (PES).

Employing a Choice Experiment methodology, we contribute to the existing knowledge regarding the economic value assigned to forest ecosystem services by assessing the willingness to pay of European citizens under future scenarios, which differ in policy ambition and forest management
Interestingly, as we explore alternative options, also based on outcomes of a project stakeholder workshop, we draw attention to emerging paradoxes within EU strategies. For instance, while provisioning services are generally perceived as undermining regulation services, the substitution of fossil fuels with wood biomass may indeed help reduc ing greenhouse gases emissions and supporting EU climate mitigation targets. Moreover, unlike many studies that treat cultural services as a n undistinguished bundle, we highlight potential conflicts arising from the increase in recreational opportunities and facilities, which may contrast with the desire to enjoy a more natural forest environment and wild biodiversity.
This research is conducted within the project ForestNavigator, involving multidisciplinary scientists dedicated to shape the future EU forests. The result of the economic assessment will be used to enhance the models employed within the project to help support both private and public actors in making well informed decisions on forests management and the preservation of their ecosystem services.

How to cite: eboli, F. and michetti, M.: Navigating Sustainable Forest Futures: Balancing Ecosystem Services in the EU, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17423, https://doi.org/10.5194/egusphere-egu24-17423, 2024.

 Heat and drought stress events have a significant impact on plant phenology. Changes in phenology can alter the length of the growing season and affect carbon, water, and energy fluxes. Some of these changes can persist for several years, especially in response to successive stress events. In this work, we combine remote sensing data and process-based modeling to investigate the effect of different heat and drought stress events on land surface phenology (LSP) and water and carbon fluxes in a deciduous and coniferous forest in southwest Germany. We used climate data to characterize different stress events for selected forest sites and as input for the process-based model LandscapeDNDC (LDNDC). For the determination of different LSP metrics we used time series of the Enhanced Vegetation Index (EVI) covering the last two decades. The evaluation of the model simulations was done using remote sensing data. The results indicated that different EVI and LSP trajectories exist for deciduous and coniferous sites. The model simulations also demonstrated that significant variations in water and carbon fluxes exist for the period during and after the stress events, and that leaf area recovery was linked to gas exchange. Since the overall forest development strongly depends on stress response strategy as well as stress frequency and intensity, combining climate projections and process-based models is needed to explore the suitability of forest response types under expected climate changes

How to cite: Moutahir, H., Petrik, P., Grote, R., and Kiese, R.: Changes in land surface phenology and gas exchange of deciduous and coniferous forests in response to heat and drought stress, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20048, https://doi.org/10.5194/egusphere-egu24-20048, 2024.

EGU24-478 | Orals | ITS3.2/ERE6.12 | Highlight

Environmental consequences resulted from the oil depots’ deterioration by the RF’s missile attacks 

Viktor Karamushka, Svitlana Boychenko, and Ruslan Havryliuk

Since the beginning of the full-scale aggression on 24 February, 2022, primary targets for missiles attacks of Russian Federation were the objects of energy sector of Ukraine.  According to the reports of the State Environmental Inspection of Ukraine, more than 30 units comprising oil depots, product warehouses, refineries, gas stations were destroyed during the March 2022 only. Most of these objects were oil depots.  The purpose of this investigation was an environmental impact assessment of the missile attacks on the petroleum depots. We analysed the cases of destruction of oil depots in Okhtyrka (Okhtyrkanaftogaz), Chernihiv (Aystra), Kalynivka (KLO) and Kryachki (AS Investment), which were completely or partially destroyed. The results of field research, satellite monitoring data, data of the State Environmental Inspection and other state bodies were used for the analysis.

As a result of the attacks, a significant part of petroleum products burned, which caused atmospheric air pollution by combustion products (carbon monoxide (CO), carbon dioxide (CO2), soot (C), nitrogen dioxide (NO2), sulphur dioxide (SO2), marginal hydrocarbons (С12-C19)). The estimated volume of emissions at the Kalynivka oil depot alone is more than 30 metric tons of carbon dioxide equivalent (mt CO2e). Spills of oil products caused pollution and partial burning of the surface layer of soils (at all bases) and penetration of oil products into groundwater with further migration over considerable distances (Kalynivka oil depot). The article presents the results of the monitoring and quantitative assessment of the soil and ground water pollution by oil derivatives as well as plant biodiversity assessment on the territory suffered from the incidents.

How to cite: Karamushka, V., Boychenko, S., and Havryliuk, R.: Environmental consequences resulted from the oil depots’ deterioration by the RF’s missile attacks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-478, https://doi.org/10.5194/egusphere-egu24-478, 2024.

Recently, rock fibers have gained attention as versatile and promising substitutes for traditional carbon and glass fibers in a range of industries, including aerospace, defence, construction, and healthcare. Shifting to the use of rock fibers represents a more sustainable and environmentally considerate approach to using natural resources. This transition likely reflects efforts to reduce reliance on less sustainable materials (such as traditional carbon and glass fibers), thereby aligning with broader goals of sustainable resource management and environmental protection. Additionally, their asbestos-free nature in construction materials makes them a healthier industrial raw material, avoiding the health hazards associated with asbestos exposure. As a result, there has been a growing interest in research initiatives aimed at evaluating the potential of volcanic rocks from diverse geographic regions for fiber production. This trend reflects an increased emphasis on understanding the geochemical properties and commercial viability of these rocks in the context of sustainable material development. Turkey's abundant volcanic rock resources offer substantial opportunities for the production of rock fibers. Recent preliminary investigations into the volcanic rocks of Central Anatolia have indicated their suitability for rock fiber production. Within the scope of this study, it is aimed to specifically evaluate the potential of Western Anatolian volcanoes for rock fiber production. Geochemical data obtained in previous studies from volcanic rocks of Western Anatolia (Afyonkarahisar, Denizli, Eskişehir, İzmir, Kütahya, Manisa, Muğla, Uşak) were used. The chemical compositions of 241 rock samples with SiO2 content of less than 63% by weight were evaluated. Using this data, key descriptive coefficients relevant to rock fiber production were calculated, including the total acidity coefficient (Ktotal), total acidity modulus (Mtotal), acidity modulus (Ma), and viscosity modulus (Mv). These metrics were then compared with those derived from rocks from Ukraine, Georgia, and Russia, currently deemed suitable for rock fiber production. Conclusively, this research highlights the potential of Western Anatolian volcanoes as viable sources for rock fiber production.

How to cite: Ünal, B. C., Kaya, S., Atalay, C., Aydar, E., and Ersoy, O.: Evaluation of the Geochemical Compositions of Western Anatolia (Turkey) Volcanic Rocks and Their Suitability for Rock Fiber Production with the Help of Fiber Modules , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-518, https://doi.org/10.5194/egusphere-egu24-518, 2024.

EGU24-541 | ECS | Posters on site | ITS3.2/ERE6.12 | Highlight

Archaeometry in geosciences: the study of ancient geomaterials for archaeological investigations. 

Francesca Gambino, Lorenzo Appolonia, Alessandro Borghi, Sylvie Cheney, Roberto Cossio, Stefano Marco De Bernardi, Giovanna Antonella Dino, Stefano Ghignone, and Gabriele Sartorio

The term "archaeometry" was first used in 1958 as the title of a special volume published by the Research Laboratory for Archaeology and Art History at Oxford University.  Archaeometry is a scientific discipline that employs various techniques primarily for the identification of sites, settlement patterns, archaeological stratigraphy, and the production and analysis of found artefacts.

Ancient buildings, artifacts, and finds consist predominantly of natural and artificial resources obtained from geological sources. Geosciences techniques are optimal for obtaining information on the origin and technological properties of archaeological artefacts and materials used in cultural heritage from geological sources.

This study conducted a petrographic and geochemical analysis of historical mortars from the Roman Theatre of Aosta and the Medieval Sarriod de la Tour Castel located in the Aosta Valley in North-West Italy. Mineralogical phase-specific distribution of elements in mortar samples was calculated using a semi-automated method of image analysis incorporating multivariate statistical analysis of X-ray spectral images. Based on SEM backscattering, a cluster image analysis was conducted to determine the ratio of aggregate, binder, and porosity. Additionally, simple algebraic operations were utilized to fully quantify the oxides in every EDS spectrum, and to compute the distribution of Hydraulicity Index (HI) within the examined domains.

This study provided many answers about supply areas, variation of raw materials over time, network/transport systems, development and production processes. The petrographic analysis has enabled identification of both the binder and aggregate type. Specifically, it has afforded information on the type of raw material used to produce the lime, the ratio of binder to aggregate, the origin of the aggregate (sedimentary or crushed rock) and its composition.

These investigations were conducted in close collaboration with archaeologists to reconstruct the exchanges between ancient civilizations and evaluate their technological progress.

Ultimately, the progress of geosciences within the field of Cultural Heritage highlights how this type of study is essential for the dissemination and museology of what represents the culture of materials from  archaeological, historical and scientific point of view.

How to cite: Gambino, F., Appolonia, L., Borghi, A., Cheney, S., Cossio, R., De Bernardi, S. M., Dino, G. A., Ghignone, S., and Sartorio, G.: Archaeometry in geosciences: the study of ancient geomaterials for archaeological investigations., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-541, https://doi.org/10.5194/egusphere-egu24-541, 2024.

In the last decade, the “storyline” approach has been developed in the field of attribution and detection of extreme climate events. Despite its merits, the storyline approach has been met with harsh criticism, especially from advocates of probabilistic (or risk-based) approaches. This reaction is amplified by the conflicting conclusions to which storylines and probabilistic approaches often lead. However, this conflict is only apparent, given that probabilistic and storyline approaches typically pursue different research concerns. Accordingly, one way to foster the legitimation of the storyline approach is by conceptualizing its epistemic contributions as a distinctive form of genuine “scientific understanding” under deep uncertainty.

The burgeoning philosophical literature on scientific understanding affords promising resources to undertake the endeavour mentioned above. However, given the recency and diversity of this philosophical field, there is still broad dissent on elementary matters, such as the nature of scientific understanding, its value, and its varieties. Following the school of "philosophy of science in practice", an informative strategy to advance philosophical debates on scientific understanding is to attend to the scientific debates between advocates of probabilistic and storyline approaches, inspect their specific practices, and assess how they should advise philosophical accounts of scientific understanding.

In this sense, there is a twofold problem. On the one hand, storylines require legitimation as an approach that affords a distinct but genuine scientific understanding. On the other hand, the very notion of genuine scientific understanding requires further philosophical elaboration, informed by scientific practices. Accordingly, this paper aims to display the synergies between the storyline approach and the philosophy of scientific understanding to foster the legitimation of the former and advance internal philosophical debates in the latter.

Three axes for synergies are identified and briefly discussed. First, the “factivity” of storyline-based understanding: Philosophers of science disagree on whether scientific understanding is solely grounded on facts or may involve non-factive representations. Storylines are a relevant method to inform these debates as they are not intended to represent factual unfoldings of extreme events. Second, the “effectiveness” of storyline-based understanding: Some philosophers of science argue that scientific understanding is not grounded on particular epistemic credentials (whether factive or non-factive) but rather on its effectiveness. However, it is unclear how untethered the effectiveness of scientific understanding can be from its epistemic credentials. The employment of storylines for decision-making under deep uncertainty affords relevant cases in which to assess the relation effectiveness and factivity of scientific understanding. And third, the “transdisciplinarity” of storyline-based understanding: An overlooked subject in the philosophical literature on scientific understanding is its relations to non-academic epistemic endeavours. This subject is relevant because i) non-academic epistemic agents and endeavours may contribute to scientific understanding, and ii) the integration of non-academic epistemic agents and endeavours into scientific research advances epistemic justice, which is critical to warrant trust in scientists and legitimize scientific understanding across stakeholders. The storyline approach is tailor-made for pondering over local knowledge and experiences, reported qualitatively, thus offering valuable opportunities for civil society to contribute to the scientific understanding of climate uncertainties.

How to cite: Bobadilla, H.: Synergies Between the Storyline Approach and the Philosophy of Scientific Understanding, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6518, https://doi.org/10.5194/egusphere-egu24-6518, 2024.

The war in Ukraine, which has been going on since February 2022, has dealt a severe blow to the country's agricultural sector. Millions of hectares of agricultural land have been destroyed by shelling, explosions, and landmines. This has raised concerns about food security in the international community, as Ukraine was a leading producer and exporter of wheat, maize, barley, and sunflower oil before the war. In order to determine the extent of the damage and develop the necessary recovery measures, as well as to formulate effective resource management strategies to ensure the sustainability of the agricultural sector, it is critical to accurately assess and locate the damaged agricultural areas.

Remote sensing, with its advantages in speed, coverage, and objectivity over ground-based methods, combined with machine learning, offers opportunities for the automatic detection of damaged fields across the entire territory of Ukraine and tracking the dynamics of damage development almost in real-time. This research demonstrates the potential of remote sensing and machine learning in detecting and analyzing damaged agricultural fields in Ukraine because of the military conflict.

We utilize freely available two-week composites from the Sentinel-2 satellite with a spatial resolution of 10 meters. The search for damaged fields is conducted in the cloud environment of Google Earth Engine using a random forest binary classifier trained on a manually collected sample by three independent experts. The input parameters for the classifier include static indicators (minimum, average, maximum, variance) of two spectral bands (B2, B3) and two vegetation indices (NDVI and GCI), which have been experimentally found to be the most informative for detecting field damage. Additionally, within the classified damaged fields, we identify local damages using an anomaly detection method. This involves measuring the deviation of values of individual pixels from the mean value of all pixels within a specific field in the spectra of the above-mentioned bands and vegetation indices.

The developed classifier achieves an accuracy of 0.9 for both recall and precision. The anomaly analysis method proves sensitive to the vegetation period and the geographical location of the study area. However, with careful selection of the threshold coefficient, the developed method demonstrates sufficiently accurate results and allows the recognition of craters with an estimated area >50 m².

The results highlight substantial losses to Ukraine's agricultural sector due to the war. It was determined that from the beginning of the conflict until December 4, 2023, more than 1.5 million agricultural fields in Ukraine were damaged, constituting approximately 5.65% of the total sown area. The most affected crops were wheat (489,529 ha or 5.78% of the total cultivated area for this crop), sunflower (115,358 ha or 1.56% of the cultivated area), maize (61,123 ha or 1.2%), and rapeseed (42,783 ha or 2.65%).

Our methods are applicable to large territories for detecting damages to various agricultural crops. The research will be valuable for assessing and restoring damaged lands, as well as for developing strategies for adaptation and resilience of the agricultural sector to other similar crisis situations.

How to cite: Drozd, S., Kussul, N., and Yailymova, H.: Evaluating the Impact of Armed Conflict on Agricultural Sector in Ukraine through Remote Sensing and Machine Learning, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10494, https://doi.org/10.5194/egusphere-egu24-10494, 2024.

EGU24-12062 | ECS | Orals | ITS3.2/ERE6.12

Long-term Monitoring of Environmental and Geophysical Impacts in Conflict-Endured Zones: A Landscape Perspective on Kivu Lake 

Ivan Lizaga, Borja Latorre, Montfort Bagalwa, Bossissi Nkuba, Samuel Bodé, Karume Katcho, Honoré Ciraba, Olivier Evrard, Karen Büscher, Koen Vlassenroot, Kristof Van Oost, William Blake, Ana Navas, and Pascal Boeckx

Human displacements, especially those driven by violent conflicts forcing sudden population migrations, wield profound and enduring impacts on landscapes, instigating substantial disruptions to the natural environment. Beyond immediate destruction, these consequences pose challenges to ecosystem health, food security, and biodiversity conservation, particularly exacerbated in the absence of effective governance. Traditional land management practices, agriculture, and conservation efforts are disrupted, constraining the implementation of long or medium-term conservation practices in agriculture. These disruptions may contribute to increased erosion and sediment transport, depleting soil nutrients and resulting in natural disasters such as flash floods, landslides, and water quality degradation. This phenomenon is particularly pronounced in regions experiencing high rainfall intensity, coupled with inadequate land use and agricultural management practices. Understanding the primary factors behind the last decades escalation in land degradation and subsequent sediment export is crucial to prevent further ecosystem degradation and heightened instability in conflict-affected areas. To address this, we have developed an integrated approach involving core sampling, sediment fingerprinting techniques, high-resolution sediment sampling, and automated remote sensing routines to pinpoint hotspot areas and track conservation efforts. Using the Lake Kivu region as a case study, situated on the border between Rwanda and the Democratic Republic of the Congo, an area marked by prolonged violent conflict since the early 1990s, we evaluate the applicability of this combined approach.

The preliminary results from the multiple techniques independently suggest an increasing trend in exported sediment over the last decade. This trend is particularly pronounced in areas characterized by high instability and economic challenges. In contrast, relatively more stable regions exhibit a stabilization in sedimentation rates. This stability is attributed primarily to the implementation of conservation practices and the presence of robust transport infrastructures, both playing crucial roles in landscape conservation. Results underscore the method's effectiveness in elucidating lasting effects on landscapes impacted by 'polycrisis', necessitating consolidated and comprehensive responses over mere technical solutions. The research objective is to target specific areas within conflict-affected regions, with a focus on mitigating environmental degradation and associated challenges.

How to cite: Lizaga, I., Latorre, B., Bagalwa, M., Nkuba, B., Bodé, S., Katcho, K., Ciraba, H., Evrard, O., Büscher, K., Vlassenroot, K., Van Oost, K., Blake, W., Navas, A., and Boeckx, P.: Long-term Monitoring of Environmental and Geophysical Impacts in Conflict-Endured Zones: A Landscape Perspective on Kivu Lake, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12062, https://doi.org/10.5194/egusphere-egu24-12062, 2024.

A particular challenge threatening global food security is the threat of armed conflict. In particular, the Panjshir valley of northeastern Afghanistan continues to experience acute food insecurity due to intense armed conflict. In this rural valley, conflict driven displacement leads to agricultural land abandonment and decreases in crop yields. These decreases in local food production have an outsized impact on food security, due to the region’s dependence on subsistence agriculture. Despite the consensus that armed conflict has a significant negative impact on the population’s food security, the exact mechanics of how conflict impacts food security remains unclear. 

 

To quantify armed conflict’s impact on local food production, I compare trends in vegetation health between agricultural plots in high-conflict and no-conflict landscapes with similar altitudinal gradients. I focus on the period during the Soviet occupation of Afghanistan from 1980-1989, which saw nine major military offensives occur in the Panjshir valley. I use Landsat 5 (1984-2012) to obtain the Normalised Difference Vegetation Index (NDVI) values for agricultural plots that have been designated as control (no conflict) and treatment (high conflict). These plots are delineated using HEXAGON KH-9 declassified spy imagery, and assigned conflict intensity designations based on explosive ordnance disposal (EOD) data from The HALO Trust, a non-governmental organisation which carries out unexploded ordnance clearance in Afghanistan. Residual Trend analysis (RESTREND) is applied to Landsat NDVI values to distinguish between the shifts in vegetation health that are anthropogenically and climatically driven. 

 

This research provides a deeper understanding of how past conflict has acted as a driver of food insecurity in the region. Additionally, it allows for future work to build off of these findings and predict how current and future conflict might have an impact. These findings can inform humanitarian and development aid policy, while the methodology can be applied to other contexts where conflict is present. 

How to cite: Allen, J.: Detecting Disturbance to Agricultural Productivity from Historical Armed Conflict in Afghanistan: The Panjshir Offensives, 1980-1985, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13525, https://doi.org/10.5194/egusphere-egu24-13525, 2024.

The considerable research on the effects of the 1815 Tambora eruption (Behringer 2015) has shown not only to what extent large tropical volcanic eruptions can transform a society but also how advantageous it is for research when geosciences and humanities interlink.

While single eruption events such as Parker in 1640/1641 have already been analysed (Stoffel et al. 2022), there has been less focus on the potential teleconnections of multiple eruptions on one single study area. This paper looks at the climatic and societal impacts of three tropical volcanic eruptions – Huaynaputina (1600), Komaga-take/Parker (1640/1641) and the 1690s unknown event – on Fribourg, a region in the western part of the Swiss Confederation.

To answer this research question meticulously, a transdisciplinary approach is required – both in method and sources. Daring to bridge geosciences and humanities, as part of the VICES research project we developed a data processing tool called ClimeApp, which facilitates the usage of climate data and makes transdisciplinary interaction more accessible, especially for researchers from the humanities (http://mode-ra.unibe.ch/climeapp).

Using ClimeApp, the climatological impact of these 17th century eruptions will be assessed with modern climate reconstruction data from the state-of-the-art ModE-RA project (Valler et al. 2024). Novel archive material from municipal institutions – such as the Hôpital des bourgeois de Fribourg – allows us subsequently to determine the annually recorded harvest yields especially of the viti- and caseiculture. Additionally, essential archival sources, such as the Ratsmanuale (protocols) and the Mandatenbücher (regulations), depict whether the municipality of Fribourg deployed any measures or coping mechanisms in the wake of these volcanic eruptions. This combination of climatological data and historical sources enables us to look for potential interrelations between these climate anomalies and the effect they had on society.

The paper exemplary highlights on one side the advantages of research collaboration between two disciplines and on the other side sheds light on the possible impacts of multiple volcanic eruptions spanned over the period of almost hundred years on the same study region.

How to cite: Bartlome, N. E. and Warren, R. M.: Visible or negligible? Impacts of the 17th century volcanic eruption on climate and society in early modern Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17186, https://doi.org/10.5194/egusphere-egu24-17186, 2024.

EGU24-17349 | ECS | Orals | ITS3.2/ERE6.12

Embracing the pitfalls and triumphs in interdisciplinary research. 

Rhonda McGovern, Dr. Francis Ludlow, Dr. Conor Kostick, and Dr. Selga Medeneiks

The Astronomical Diaries and Related Texts from Babylonia is a seven volume transliteration and translation of collected cuneiform texts, originally written on clay tablets, from Babylon (modern day Hillah in Iraq). For many centuries in the first millennium BCE, trained scribes positioned themselves night and day to watch and record the skies. It is the compilation of this work that embodies what are known today as the “astronomical diaries”. These texts provide a wealth of data ranging from sub-daily resolution to monthly summaries including: astronomical features and the movement of stars and planets; market prices for six commodities; river level heights for the Euphrates river; information regarding contemporary events; and meteorological data, which was systematically recorded using specific terminology for particular weather phenomena. So precise is this terminology that a few terms remain untranslated. To date, much work has been conducted on these diaries with the exception of the meteorological data. Doctoral research of the presenting author has involved extracting this into a large dataset to facilitate future analysis.

This research is conducted in an interdisciplinary context, within the wider Climates of Conflict in Ancient Babylonia project, where colleagues explore the potential impact of climate on conflict. The team is comprised of a climate historian with a background in geography, a historian, a geographer and a classicist, who interact with historical linguistic experts, climate modellers, climate scientists, and palaeoscientists. As in this project, the application of historical research is becoming increasingly prevalent in the geosciences. Historic texts have the potential to reveal implicit clues to climatic investigations. The Astronomical Diaries and Related Texts from Babylonia provide, for example, intriguing descriptions of events in which “the disk of the sun looked like that of the moon”, identified as volcanic dust veils and already utilised in updating ice-core chronologies of volcanic eruptions over the last 2,500 years.[1]

This paper will narrate the process of extracting climatic data from historical sources; highlight the pitfalls and triumphs in terms of the practicalities of this interdisciplinary research; and provide a volcanic impacts case study, continuing the scientific endeavour instigated by Babylonian scribes over 2,000 years ago.


[1] Sigl, M., M. Winstrup, J. R. McConnell, K. C. Welten, G. Plunkett, F. Ludlow, U. Büntgen, et al., ‘Timing and climate forcing of volcanic eruptions for the past 2,500 years’ in Nature, dxxiii, no. 7562 (2015), pp. 543–549.

How to cite: McGovern, R., Ludlow, Dr. F., Kostick, Dr. C., and Medeneiks, Dr. S.: Embracing the pitfalls and triumphs in interdisciplinary research., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17349, https://doi.org/10.5194/egusphere-egu24-17349, 2024.

EGU24-19686 | Posters on site | ITS3.2/ERE6.12 | Highlight

Climate variability and food (in)security in medieval and early modern Europe: synthesising the state-of-the-art 

Fredrik Charpentier Ljungqvist, Andrea Seim, and Dominik Collet

On the basis of our new state-of-the-art research review article “Famines in medieval and early modern Europe – Connecting climate and society”, published in WIREs Climate Change this year, we provide an overview of recent scholarship on food insecurity and famines in Europe during the medieval and early modern periods (c. 700–1800). Focus is placed on how, and to what extent, climatic change and variability can explain the occurrence and severity of food shortages and famines during these periods. Current research, supported by recent advances in palaeoclimatology, has revealed that anomalous cold conditions were the main environmental backdrop for severe food production crises that could result in famines in pre-industrial Europe. Such food crises occurred most frequently between c. 1550 and 1710 during the climax of the Little Ice Age cooling. They can, to a large extent, be connected to the strong dependency on grain in Europe during this period and the limited possibility for long-distance transportation of bulk goods in inland regions. The available body of research demonstrates that famines in medieval and early modern Europe can be best understood as the result of the interactions of climatic and societal stressors responding to pre-existing societal vulnerabilities. We provide some recommendations for future studies on historical food shortages and famines in connection to climatic stress on food production.

How to cite: Charpentier Ljungqvist, F., Seim, A., and Collet, D.: Climate variability and food (in)security in medieval and early modern Europe: synthesising the state-of-the-art, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19686, https://doi.org/10.5194/egusphere-egu24-19686, 2024.

EGU24-20528 | ECS | Posters on site | ITS3.2/ERE6.12

Investigating Impacts of Climate Change and War on the Green Cover Area in Northeast Syria Between 2000 and 2023 

Abdullah Sukkar, Sara Essoussi, Omar Alqaysi, Enes Hisam, and Dursun Zafer Seker

During the 20th century and continuing into the present, significant warming was observed due to the emission of greenhouse gases, primarily CO2 and CH4, into the atmosphere. The sixth assessment report of the Intergovernmental Panel on Climate Change estimates a warming of 1.1°C above 1850-1900 in 2011-2020. As climate warming continues to reshape atmospheric conditions and trigger extreme weather events such as drought, forest fires, and floods. The intricate relationship between these changes and vegetation dynamics becomes increasingly evident, profoundly affecting ecological systems, agriculture, and politics. Vegetation is an essential component in ecological systems since it serves as a connection between soil, atmosphere, and water; and plays a crucial role in maintaining the balance of carbon and water, facilitating the exchange of materials and energy, ensuring climate stability, and reducing greenhouse gas emissions. Generally, changes in vegetation are analyzed to assess the environmental conditions at both regional and global levels. The normalized difference vegetation index (NDVI) is a commonly employed tool for analyzing variations in vegetation dynamics. Examining these changes and their triggers is crucial for comprehending the relationships between vegetation and ecosystems. Syria, located at the intersection of Asia and the Mediterranean, is an area with a high level of water scarcity and is susceptible to extreme droughts, especially in the northeastern region, where temperature and evaporation have significant impacts. The land cover in the northeastern region has undergone significant alterations in recent decades due to the armed conflict, which its effects on the land use and land cover (LULC) are neither unidirectional nor spatially uniform. Research and policy alike have given careful consideration to the relationship between conflict and climate change. Extreme weather events, like droughts, have been shown to correspond with the start of armed conflicts occasionally. The most widely proposed mechanism between climate change and violent conflict is the relationship between shocks to agricultural productivity and the degradation of vegetation. In this study, the ERA5-Land data has been used to analyze the climatic conditions in northeast Syria between 2000 and 2023. In addition, the satellite images of Landsat 5, 7, 8, and 9 have been used to generate NDVI maps. Then, a correlation between the meteorological parameters and the NDVI was established to examine how climate change and drought have affected the green cover in the study area, especially after 2011, when the armed conflict started. Meteorological parameters such as temperature, soil temperature, precipitation, and evaporation on an hourly scale have been applied. The drought events have been addressed by the number of precipitation events, precipitation accumulation, and precipitation intensity. Moreover, the Standardized Precipitation Index (SPI), which is considered as a global standard for evaluating the severity of drought, has also been used for various time scales (3, 6, 9, and 12 months). The study highlighted how climate change had affected the vegetation areas in the northeastern region of Syria. The results emphasized different drought events and mapped the change in the LULC through the time period of the study.

How to cite: Sukkar, A., Essoussi, S., Alqaysi, O., Hisam, E., and Seker, D. Z.: Investigating Impacts of Climate Change and War on the Green Cover Area in Northeast Syria Between 2000 and 2023, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20528, https://doi.org/10.5194/egusphere-egu24-20528, 2024.

EGU24-20730 | Orals | ITS3.2/ERE6.12 | Highlight

Detecting the undecteable: transhumant nomads in palynological data 

Adam Izdebski and Georgios Liakopoulos

Nomadic communities are difficult to detect in the written and material record historians and archaeologists traditionally use to study the past. Contrary to settled grain cultivators, who were easy target for state taxation and were often recorded in a variety of documents, or who left easy to detect traces of permanent villages, nomads often remained outside of the radar of the traditional sources. Nomadic communities, however, profoundly transformed landscapes they lived in. These landscapes, in turn, produced different environmental signals that are preserved in the sedimentary records. Pollen data, in particular, make it possible to reconstruct the presence and activities of nomads in a given area, filling in the gaps in the historical and archaeological record. In our short presentation, we will look at high resolution pollen evidence from Macedonia (Northern Greece) that could be used to trace the presence of transhumant nomads in this region in the last two millennia. We will show how the paleoenvironmental reconstruction can be connected to otherwise fragmentary and problematic written information to create a consilient reconstruction of the past, recovering the presence of diverse groups that inhabited the Northern Greek landscape in the medieval and early modern times.

How to cite: Izdebski, A. and Liakopoulos, G.: Detecting the undecteable: transhumant nomads in palynological data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20730, https://doi.org/10.5194/egusphere-egu24-20730, 2024.

EGU24-21661 | Posters virtual | ITS3.2/ERE6.12

Post-war rewilding as a decision-making influence-factor 

Yuliia Spinova and Oleksii Vasyliuk

Military actions create a number of destructive effects on natural and agricultural landscapes. These influences, which can be seen now during Russia's war in Ukraine, are short-term and their role in the future will consist more in how exactly they will change the territories usage regime. Long-term inaccessibility of territories due to occupation, mining and land pollution are the cause of large-scale spontaneous restoration of semi-natural ecosystems. While Ukraine does not have the opportunity to implement restoration projects on the occupied lands, there continue natural transformation processes that will determine the content of decisions to be made.

For example, the former Kakhovske Reservoir, which HPP and dam were blown up by retreating Russian troops on June 6, 2023, and water flooded out of it. Our research showed almost immediately recovering of native vegetation there. By the end of the year, this recovery led to the natural young forest appearance on a large area freed from the artificial reservoir. This process will allow to restore up to 1,800 km2 of natural ecosystems (of which at least 1,000 km2 will be climate-resistant forests) and about 250 km of the free-flow Dnipro river. Such a large ecosystem restoration can become a decisive Ukrainian contribution to the European Union ecosystems revival by 2030.

On the other hand, if the project of the Kakhovske Reservoir restoration, which requires the destruction of all the mentioned square kilometers of natural ecosystems, will be implemented, this is categorically not in line with the ideas of sustainable development. Therefore, the natural processes of recovery will significantly influence the decision-making in Ukraine and its support by the partner states.

In fact, the scale of these processes is already impressive. A comparison of MODIS thermal imaging data for the year 2023 with similar ones of previous years shows that all areas where hostilities were/are being conducted, as well as mined, have turned into large-scale overgrowth with vegetation. Thus, intensive spontaneous vegetation overgrowth, caused by the local population outflow local population and the economic influence cessation of economic influence, including plowing and pesticides use, is already taking place on an area about 1 million hectares. In the short-term perspective undoubtedly there are significant component of invasive plant species, but native perennial species will gradually displace them over time.

Currently, it is not known how long the occupation will last, let alone its demining. According to preliminary estimates of the Cabinet of Ministers of Ukraine, announced in 2022 - more than 70 years. In this case carrying out demining, there may already grow a 70-year-old forest on the aftermost territories, and mines will be buried deep in the ground under tree roots. So already now the expediency of complete demining can be questioned and we offer not to plan it for the most injured territories and around protected areas. Spontaneous ecosystem restoration there can become a powerful contribution of Ukraine into state tasks on preservation of degraded lands, as well as international obligations in the field struggle from climate change.

How to cite: Spinova, Y. and Vasyliuk, O.: Post-war rewilding as a decision-making influence-factor, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21661, https://doi.org/10.5194/egusphere-egu24-21661, 2024.

EGU24-21994 | Posters virtual | ITS3.2/ERE6.12

Study of the military actions impact on the Buchansky district soils (Kyiv Region, Ukraine) 

Yuliia Spinova, Iryna Vyshenska, Anastasia Sakva, and Oleksii Vasyliuk

Soil damage as a result of military actions is primarily associated with shell bursts, as well as with the movement of heavy equipment, fortifications construction and related processes, such as fires caused by them and following changes in the phytodiversity.

The impact on the physical condition of soils occurs through a pneumatic effect - that is, upturning the soil by explosions, and changes due to the equipment movement, digging trenches and other fortifications.

Changes in the chemical and biological characteristics of the soil occur as a result of animal and human corpses decomposition products, of fuels and lubricants leakage from heavy equipment, and also a large amount of abandoned equipment, or its remnants, chemicals from projectiles and debris contamination.

Shelling accompanied by explosions, as well as the use of lighting and incendiary projectiles led to large-scale fires, which deplete soil nutrients (particularly humus and minerals such as magnesium and phosphorus). In addition to changing the chemical composition, high temperatures destroy pedobionts, which have a direct impact on both the chemical and physical condition of the soil, and are responsible for its fertility and stability. In the future, such changes may lead to accelerated erosion. Oil products from heavy machinery are quickly absorbed, especially into dry and sandy soils. As a result, physical and chemical characteristics change, water and air permeability and microbiological processes are disturbed, so soil degradation occurs. Besides the direct impact, the process of soil contamination with fuel substances can lead to easy ignition and large-scale fires.

The most widely used weapons in this war are 82 mm and 120 mm high-explosive shells, 125 mm high-explosive and cumulative shells, 122 mm, 152 mm, 203.3 mm, 240 mm high-explosive, incendiary and illuminating shells.

We made calculations of the burnings spread, identified correlations between them and shellings using QGis and NASA data on the Buchansky district for February 24, 2022 – June 26, 2022. In total, 2.712 burnings were detected for that 4 months of Russia's full-scale invasion on the territory of Buchansky district (area is 2.558 km²). Most of them took place within the settlements where battles were fought.

With satellite images from the open database of Maxar Technologies we analyzed the most affected soil surfaces in this district.

One of the chosen plots is represented by the Irpin River meadows and is the Emerald network site. 18 impact marks were counted here in total: 4 bursts from 82-mm shells, 8 bursts from 122-mm and 6 – from 152-mm shells. An additional external analysis of a young pine forest area showed the vegetation overgrowth is no more than 10% after 2.5 months of succession process and represented by ruderal and segetal plant species.

Moreover, 8 objects of the Nature Reserve Fund of Ukraine with particularly valuable ecosystems in the Buchansky district were affected by military operations and their stability is currently significantly reduced.

How to cite: Spinova, Y., Vyshenska, I., Sakva, A., and Vasyliuk, O.: Study of the military actions impact on the Buchansky district soils (Kyiv Region, Ukraine), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-21994, https://doi.org/10.5194/egusphere-egu24-21994, 2024.

EGU24-444 | ECS | Posters on site | ITS1.5/NP8.6

Multifractal analysis of recent precipitation projections in the context of climate change 

Pedro Henrique Dias Kovalczuk, Daniel Schertzer, and Ioulia Tchiguirinskaia

Despite efforts to obtain consistent results, the prediction of patterns in the behavior of geophysical fields still faces many uncertainties. However, these analyses are important for studying the effects of human action on the environment and the effects reflected in climate change. There is much evidence that Multifractals are capable of describing intermittent behavior and statistical data of all orders and over a wide range of scales. Therefore, this work consists of using the multifractal framework to analyze recent precipitation projection data in France, verifying the evolution of its parameters over a relatively long period of time (from 1951 to 2100) and over space, using 12 points on French territory with a resolution of 2.8º x 2.8º. For this, the Double Trace Moment technique was applied to determine the mean intermittency codimensions, the multifractality indexes and the maximum probability singularities. These results were compared to the article by J.-F. Royer et al., C. R. Geoscience 340 (2008) to verify if projections remained consistent with changes in data and economic scenarios. Despite the differences found in the range of parameter values ​​and scaling behavior, recent data also indicated an increase in intermittency over time and presented spatial behavior similar to old projections, which reinforces the expectation of an increase in precipitation extremes in the coming decades.

How to cite: Dias Kovalczuk, P. H., Schertzer, D., and Tchiguirinskaia, I.: Multifractal analysis of recent precipitation projections in the context of climate change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-444, https://doi.org/10.5194/egusphere-egu24-444, 2024.

EGU24-531 | ECS | Posters on site | ITS1.5/NP8.6

Combining Generative Adversarial Networks with Multifractals for Urban Precipitation Nowcasting  

Hai Zhou, Daniel Schertzer, and Ioulia Tchiguirinskaia

Precipitation nowcasting, referring to short-term forecasting ahead for 0 to 6 hours, is an important aspect of many urban meteorological and hydrological studies. This is due to the fact that reliable nowcasting can serve as an early warning of massive flooding and a guide for water-related risk management, making it highly significant in urban areas from a socio-economic perspective. Precipitation exhibits extreme variability over a wide range of space-time scales, so nowcasting is essentially a spatiotemporal sequence forecasting. Convolutional long short-term memory (ConvLSTM) models are frequently used to capture the spatiotemporal correlation, but they often struggle with an issue that produces blurry predictions. Therefore, generative adversarial network (GAN) architecture is employed to achieve more detailed and realistic predictions. The framework of universal multifractal (UM) with only three scale-independent parameters (α, C1, H) is also introduced in the deep learning model to characterize the extreme variability of precipitation. The developed hybrid approach using stochastic models physically based on the cascade paradigm ensures that intermittency is directly taken into account, including in the generation of uncertainty. In addition to the common evaluating metrics, like mean absolute error (MAE), root mean squared error (RMSE), critical success index (CSI), probability of detection (POD), power spectral density (PSD) and UM are also introduced to evaluate nowcasting performance in the spectrum space. This ongoing work is based on the previous research about combining recurrent neural networks with variational mode decomposition and multifractals to predict rainfall time series in Paris area.

How to cite: Zhou, H., Schertzer, D., and Tchiguirinskaia, I.: Combining Generative Adversarial Networks with Multifractals for Urban Precipitation Nowcasting , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-531, https://doi.org/10.5194/egusphere-egu24-531, 2024.

Urbanization induced carbon dioxide (CO2) emissions have attracted widespread attention.

A comprehensive attribution analysis model is designed to understand the inherent uncertainties in diagnosing the effects of urban expansion dynamics and modes on carbon dioxide (CO2) emissions. First, 68 selected cities across China are categorized into three types, including expanding, contracting, and staying cities, through developing an evaluation indicator system by integrating population, economy, construction, and social information. Next, the carbon dioxide (CO2) emissions of the cities were quantified. The Lasso method was employed to select the factors influencing CO2 emissions. For cities with different development modes, the XGBoost regression model with SHAP algorithm was employed to calculate the contribution rate of various factors to carbon emissions in different types of cities. Additionally, the analysis considered the temporal changes of these factors.

The main conclusions are as follows:

(i)Comparing urban built-up areas extracted from the nighttime light dataset with China's national land use and cover change dataset, the results reveal a minimum correlation of 0.72-0.82 and an average overall accuracy of 78%.

(ii)The urbanization process of 68 cities exhibits a predominant pattern of normal fluctuations, with a coexistence of expansion and contraction. The results indicate that over the past 20 years, expanding cities have been concentrated mainly in coastal regions such as the Yangtze River Delta and the Pearl River Delta, while contracting cities are primarily found in inland areas characterized by traditional industrial cities. It is observed that the development processes of most cities involve an initial phase of intensive expansion (or contraction), followed by a gradual trend towards stability in the later stages.

(iii)The factors influencing carbon emissions in expanding and contracting cities share commonalities and differences. Population and energy efficiency both have significant impacts on carbon emissions in different types of cities. For expanding cities, the impact of green area on carbon emissions is more pronounced. Conversely, in contracting cities, the influence of foreign trade is more significant.

How to cite: Qian, J. and Cai, D.: The impact of the expansion and contraction of China’s cities on CO2 emissions,2002-2021,evidence from integrated nighttime light data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-821, https://doi.org/10.5194/egusphere-egu24-821, 2024.

EGU24-1003 | ECS | Orals | ITS1.5/NP8.6

A Transformer-Based Model for Effective Representation of Geospatial Data and Context 

Rui Deng, Ziqi Li, and Mingshu Wang

Machine learning (ML) and Artificial Intelligence (AI) models have been increasingly adopted for geospatial tasks. However, geospatial data (such as points and raster cells) are often influenced by underlying spatial effects, and current model designs often lack adequate consideration of these effects. Determining the efficient model structure for representing geospatial data and capturing the underlying complex spatial and contextual effects still needs to be explored. To address this gap, we propose a Transformer-like encoder-decoder architecture to first represent geospatial data with respect to their corresponding geospatial context, and then decode the representation for task-specific inferences. The encoder consists of embedding layers that transform the input location and attributes of geospatial data into meaningful embedding vectors. The decoder comprises task-specific neural network layers that map the encoder outputs to the final output. Spatial contextual effects are measured using explainable artificial intelligence (XAI) methods. We evaluate and compare the performance of our model with other model structures on both synthetic and real-world datasets for spatial regression and interpolation tasks. This work proposes a generalizable approach to better modeling and measuring complex spatial contextual effects, potentially contribute to efficient and reliable urban analytic applications that require geo-context information.

How to cite: Deng, R., Li, Z., and Wang, M.: A Transformer-Based Model for Effective Representation of Geospatial Data and Context, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1003, https://doi.org/10.5194/egusphere-egu24-1003, 2024.

EGU24-1223 | ECS | Orals | ITS1.5/NP8.6

Spatial and Temporal Analysis for Identifying the Movement of Chronic Kidney Disease (CKDu) Hotspots; in Reference to River Basins in North Central Province, Sri Lanka 

Charunika Sandamini Arambegedara, Yu Lijun, Danlu Cai, Jianfeng Zhu, Asanga Venura Ranasinghe, and Ambepitiyawaduge Pubudu De Silva

In recent years, Sri Lanka has experienced a high prevalence of chronic kidney disease (CKDu) in certain regions, especially in the North Central Province (NCP). The etiology of this disease is not yet clearly understood, although several hypotheses involving environmental and occupational factors have been proposed. To better understand the patterns of CKDu incidence and its potential relationship to environmental factors, a spatial and temporal analysis was conducted using geographic information system (GIS) tools. In this study, we identified the geographical hotspots of CKDu incidence over a period of eleven years (from 2010 to 2020) in the NCP, of Sri Lanka. The analysis was done for the districts of Anuradhapura and Polonnaruwa in NCP. Furthermore, we analysed the temporal trends of CKDu incidence by comparing the disease burden between different years. Finally, we examined the association between river basins and CKDu incidence by overlaying the spatial layers of the disease incidence and river basins. Our results showed that there were significant spatial and temporal variations in CKDu incidence in the region over the study period. The disease is characterized by a fluctuating trend. Also, the number of hotspots has decreased over time, and the number of CKDu-affected patients has also decreased. Similarly found that CKDu hotspots were concentrated around the mainly 4 river basins in the region, indicating a possible link between water resources and the disease. By identifying CKDu hotspots and understanding the disease's movement over time, public health officials can target their efforts more effectively, reducing the disease's impact on affected communities. This study provides important insights into the spatial and temporal patterns of CKDu and suggests the need for further research to investigate the potential environmental risk factors contributing to this disease.

 

Key Words: Chronic Kidney Disease of Unknown Etiology (CKDu), Hotspots Analysis, Spatial and Temporal Variation, Geographical Information System (GIS)

How to cite: Arambegedara, C. S., Lijun, Y., Cai, D., Zhu, J., Ranasinghe, A. V., and Silva, A. P. D.: Spatial and Temporal Analysis for Identifying the Movement of Chronic Kidney Disease (CKDu) Hotspots; in Reference to River Basins in North Central Province, Sri Lanka, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1223, https://doi.org/10.5194/egusphere-egu24-1223, 2024.

Cities play a crucial role in climate neutrality because although they occupy only 4% of the EU land area, they host 75% of its population. In addition, they consume over 65% of global energy and account for more than 70% of global CO2 emissions. As climate change mitigation depends on urban action, the EU has decided to support cities in accelerating their green and digital transformation. The EU Mission on Climate-Neutral and Smart Cities aims to make the participating cities climate neutral and smart by 2030, in areas such as energy, waste management, transport, and buildings, to improve the quality of life. A WEBGIS Smart City Geospatial Framework has been developed for the Limassol Municipality in Cyprus. The establishment of a Smart City Geospatial Framework is imperative for several reasons. Firstly, it enables data-driven decision-making, allowing city officials to make informed choices about urban planning and resource allocation. Secondly, it enhances the efficiency of public services, such as transportation and emergency response, by leveraging real-time spatial data. Moreover, the framework promotes sustainability by providing insights into environmental factors, contributing to eco-friendly urban development. Lastly, the integration of geospatial technologies fosters citizen engagement, transparency, and overall improvement in the quality of life for urban residents. Under this WEBGIS smart city framework, the authors explore the importance of supporting the Limassol Municipality under the EU Mission for climate-neutral and smart cities by 2030 initiative, using the proposed WEBGIS smart city framework.  Results are presented using the GIS dashboard.

How to cite: Papantoniou, A., Danezis, C., and Hadjimitsis, D.: Exploring the importance of using a novel Smart City Geospatial Integrated Framework for supporting Cities participating in EU Mission for climate-neutral and smart cities by 2030: the case study of Limassol in Cyprus., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1502, https://doi.org/10.5194/egusphere-egu24-1502, 2024.

Information on urban groundwater in Vienna is important not only to secure a sustainable use and supply but also to protect groundwater quality. Here, we provide a compilation of available information and data to cover all relevant aspects of hydrogeology within the city in order to improve planning and policy making with regard to water extraction, geothermal use and groundwater protection.

We propose a grouping of the Quaternary and Neogene sediments as well as of the underlying sedimentary rocks of the Flysch zone and the Calcareous Alps, into hydrogeological units with distinct properties. Each unit is described regarding lithology, aquifer type, groundwater occurrence and yield. Additionally, the area percentage of sealed ground surface and the conditions of groundwater recharge are defined. Finally, the types of groundwater use, withdrawal rates, hydrochemical signatures and heavy metal contents are characterized.

Limestones and dolomites of the Calcareous Alps represent high yield karst aquifers with calcium-magnesium-bicarbonate-type hydrochemistry, used as spa water drawn from 800 m deep, artesian wells.

Within the Flysch zone, clay- and marlstones act as aquitards while sandstones constitute fractured or double-porosity aquifers which are partially confined, of low yield and used locally for drinking water, industrial water and irrigation. At the surface, the zone occurs in the Vienna Woods, where groundwater recharge through rain water can be high within sandstone areas.

Where Neogene silts and clays contain sand and gravel layers, these represent porous aquifers of low to medium yield, used mainly for irrigation, industrial water and geothermal purposes. Groundwater recharge from the surface is impeded by a thick loess cover. In the eastern part of the city, groundwater in a conglomerate layer of 300 m thickness and 3000 m below ground, reaches temperatures of up to 100°C and is considered Vienna’s future geo-energy reservoir.

Pleistocene terraces are made of gravel and, with decreasing age, show decreasing amounts of sand and silt intercalations, while the groundwater shows increasing yield, increasing mineralisation and major ion contents shifting from Ca and Mg dominance towards more Na and K. The terraces’ occurrence coincides with intense urban land use, sealing of the ground surface, low recharge and potential infiltration of leaking sewage water.

Within the Danube plain, 60 % of the land is used for agriculture and recreation where rain water can infiltrate easily into Holocene gravel. Recharge also happens partially through river bank filtrate of the Danube, partially through artificial recharge. Among all groundwater units in Vienna, this continuous aquifer shows the highest yield and the most intense use for irrigation and groundwater heat pumps. During peak periods of water demand, groundwater is also used as drinking water.

Vienna’s water consumption amounts to 200 litres per person per day approximatively. In periods of normal demand, drinking water is provided exclusively by Alpine karst springs captured up to 120 km southwest of the city.

How to cite: Pfleiderer, S.: The hydrogeological units of Vienna - land use, groundwater use and groundwater chemistry, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1818, https://doi.org/10.5194/egusphere-egu24-1818, 2024.

EGU24-2965 | Orals | ITS1.5/NP8.6

How do urban river networks regulate city climate? A case study in Shanghai, China 

Jiyun Song, Dachuan Shi, and Qilong Zhong

Urban blue (water) and green (vegetation) spaces are natural refuges of cool spots for citizens to escape from the extreme heat outdoors and have been widely used in traditional and modern urban designs called ‘water towns’ (i.e., buildings are sited along rivers and trees), particularly in Southern China with rich water resources. This study represents the first comprehensive investigation into the cooling effect of urban river networks at different climatic scales in Shanghai, a Chinese megacity characterized by a significant presence of water towns. At the neighborhood scale, we conducted fine-resolution street-level monitoring of microclimatic data along various rivers during the 2022 heatwave periods in central Shanghai and applied an advanced spatial regression algorithm to quantify the synergistic effect of river and vegetation. At the city scale, we quantified the cooling buffer zones and cooling intensities of urban river networks by integrating fine-resolution urban river network maps with multi-source remotely sensed datasets. We found that the width of rivers, coverage ratio, density, and morphology of river networks are the key factors affecting the cooling potential. The confluence or proximity of river tributaries can also bring an enhanced cooling effect than standalone ones. In a diurnal cycle, rivers can lead to an averaged cooling intensity of 0.4–0.8 °C in air temperature with a maximum value of 3.5 °C in the afternoon, as well as a cooling distance ranging from 100 m to 700 m at various riverside neighborhoods. On the other hand, city-scale results show that river networks can provide a considerable cooling buffer zones covering 36.9% of Shanghai and a maximum cooling intensity of 5.5 °C in surface temperature. Our study implies that urban river networks cannot be neglected in urban climatic studies and should be incorporated into a new conceptualization of water-included urban local climate zone classifications in the world urban database.

How to cite: Song, J., Shi, D., and Zhong, Q.: How do urban river networks regulate city climate? A case study in Shanghai, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2965, https://doi.org/10.5194/egusphere-egu24-2965, 2024.

EGU24-3246 | Posters on site | ITS1.5/NP8.6

WRF-SUEWS Coupled System: Development and Prospect 

Ting Sun, Hamidreza Omidvar, Zhenkun Li, Ning Zhang, Wenjuan Huang, Simone Kotthaus, Helen Ward, Zhiwen Luo, and Sue Grimmond

We present the coupling of the Surface Urban Energy and Water Scheme (SUEWS) into the Weather Research and Forecasting (WRF) model, which includes pre-processing to capture spatial variability in surface characteristics. Fluxes and mixed layer height observations from southern UK were utilised to assess the WRF-SUEWS system over two-week periods across different seasons. Mean absolute errors are lower in residential Swindon compared to central London for turbulent sensible and latent heat fluxes (QH, QE), with increased accuracy on clear days at both locations. The model's performance exhibits clear seasonality, showing enhanced precision for QH and QE during autumn and winter due to more frequent clear days than in spring and summer. Using the coupled system, we explored how anthropogenic heat flux emissions affect boundary layer dynamics by contrasting areas with varying human activities within Greater London; higher emissions not only raise mixed layer heights but also create a warmer, drier near-surface atmosphere. Future updates will align the coupled system with the latest SUEWS version, focusing on detailed surface-layer diagnostics that can support various urban climate applications such as building energy modelling and human thermal comfort assessments.

How to cite: Sun, T., Omidvar, H., Li, Z., Zhang, N., Huang, W., Kotthaus, S., Ward, H., Luo, Z., and Grimmond, S.: WRF-SUEWS Coupled System: Development and Prospect, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3246, https://doi.org/10.5194/egusphere-egu24-3246, 2024.

Urban overheating is becoming an increasingly pressing concern under the dual challenges of global warming and urban heat island effect. One effective way to mitigate urban overheating problems is to create urban cool spots via urban blue-green spaces (BGS).  To investigate the synergistic cooling effect of urban BGS, we proposed a new urban BGS coupling system by integrating a new urban water module with the state-of-the-art urban vegetation module in the framework of an urban canopy model (UCM). This coupled BGS system can represent complicated radiative exchanges between building, tree, and water, and simulate dynamic variations of shadow length, temperature, humidity, as well as energy and water fluxes within the urban street canyon. The new urban BGS model has been evaluated in typical neighborhoods with building and trees siting along rivers (also named ‘water towns’) in two Chinese megacities, i.e., Shanghai and Hong Kong. Based on this model, we investigated the synergistic cooling effect of BGS in different ‘water town’ design scenarios with different combinations of BGS characteristics (e.g., tree crown radius and height, river width, the distance between tree and river) and street canyon characteristics (e.g., geometries and orientations). Our study emphasizes the importance of optimizing 'water town' design to offer more effective cool spots for urban citizens facing escalating heat stress.

How to cite: Shi, D. and Song, J.: Investigating the synergistic cooling effect of urban blue and green spaces via an advanced urban canopy model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4483, https://doi.org/10.5194/egusphere-egu24-4483, 2024.

EGU24-6045 | Orals | ITS1.5/NP8.6 | Highlight

Improved representation of anthropogenic deposits in 3D urban geological subsurface models 

Jeroen Schokker and Joris Dijkstra

The urban subsurface is increasingly disturbed by human activity and/or covered by anthropogenic deposits. This is particularly true for city centres, with thick and heterogeneous subsurface archives related to historical urban development, as well as for modern residential and industrial areas, that are often built on extensive sheets of filling sand. The anthropogenic deposits may be very diverse in nature, ranging from natural aggregates (crushed rock, gravel, sand or clay) to various types of novel anthropogenic materials (e.g. steelworks slags, concrete and rubble), as well as mixtures of these.

Although anthropogenic deposits could be represented on subsurface maps and in 3D models, these deposits are often omitted. Their lateral extent and thickness are not well constrained and relevant information on the lithological properties of the deposits is generally lacking. At the same time, the demand for complete and detailed subsurface information in the built environment is increasing and relates to anything from building stability and ground heat extraction to preserving cultural heritage and mitigating the effects of climate change.

This presentation therefore focusses on the lithological characterisation and stratigraphical subdivision of anthropogenic deposits in order to improve their representation in 3D geological subsurface models. We will evaluate current lithological standards and stratigraphic approaches and present the principles of the approach that we are developing in the Netherlands. We will discuss the practical consequences and give examples of bringing our approach into practice. Ultimately, a well-thought lithological description and classification system of anthropogenic deposits is a prerequisite to produce reliable subsurface and coupled surface-subsurface models. In that way, we can address the many challenges related to the ever-increasing use of  urban space and thus improve the wellbeing of our citizens.

How to cite: Schokker, J. and Dijkstra, J.: Improved representation of anthropogenic deposits in 3D urban geological subsurface models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6045, https://doi.org/10.5194/egusphere-egu24-6045, 2024.

EGU24-7877 | ECS | Orals | ITS1.5/NP8.6

Multiscale characterisation of varied risks for transportation infrastructures under climate change 

Yangzi Qiu, Pierre-Antoine Versini, Nathanaël Mifsud-Couchaux, and Ioulia Tchiguirinskaia

The infrastructures of Régie Autonome des Transports Parisiens (RATP) system are significant for the transportation of the Île-de-France region, providing essential social and economic services. In order to assess and mitigate the negative impact of climate change, this study aims to characterise the flood and heat wave risks of RATP infrastructures under climate change on multiple scales. Extreme flood events and heat wave events may result in the functional disruptions to the RATP infrastructures by interrupting circulation for more or less long periods. Therefore, a better understanding of the multi-scales risk (combining hazard, exposure and vulnerability indicators) of RATP infrastructures could enhance their resilience to climate change. With this respect, a multi-scale analysis of flood and heat wave risks of RATP infrastructures is presented by integrating the Universal Multifractal (UM) framework and analytic hierarchy process (AHP). The UM framework is a stochastic method that allows analysis of the natural hazards (extreme precipitation and temperature) and risks under three future climate scenarios (RCP2.6, RCP4.5, RCP8.5) across a range of scales. The AHP method is applied for quantifying the various risks by weighting hazard, exposure and vulnerability indicators based on experts’ knowledge. The results show that a certain number of RATP stations and lines are prone to flood and heat waves under climate change, especially in the RCP8.5 scenario. By undertaking the multiple scales of flood and heat wave risks of RATP infrastructures, this study seeks to contribute valuable insights that will inform strategic planning and resilience-building initiatives for RATP infrastructures under climate change (adaptation measures). It provides a theoretical basis for multiple risk assessments in other metropolitan areas worldwide.

How to cite: Qiu, Y., Versini, P.-A., Mifsud-Couchaux, N., and Tchiguirinskaia, I.: Multiscale characterisation of varied risks for transportation infrastructures under climate change, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7877, https://doi.org/10.5194/egusphere-egu24-7877, 2024.

EGU24-8391 | Orals | ITS1.5/NP8.6

Urban hydrogeologic uncertainty characterisation to evaluate risk of groundwater flooding 

Charalampos Ntigkakis, Stephen Birkinshaw, Ross Stirling, and Brian Thomas

Groundwater flooding within the urban infrastructure can play a major role in determining the resilience of urban environments. Urban groundwater models can be used to simulate the complex interactions between surface water and groundwater within the urban system and can be developed to jointly account for groundwater-surface water processes and subsurface characterization. They can be used to simulate potential groundwater flooding and help understand the role of groundwater in urban resilience to climate change. However, urban groundwater is a component of the wider urban water system that has traditionally been overlooked, and the complex interactions between surface water and groundwater may obscured by urban infrastructure and its influence on groundwater flow. Furthermore, the subsurface characterisation is an integral part of any groundwater model, however it’s influence on model performance is not yet fully understood. Therefore, the inherent complexities of the urban environment, combined with the scarcity of appropriate groundwater and subsurface data, can lead to increased model uncertainty. It is argued that robust urban groundwater modelling depends on a strong conceptual understanding of the groundwater system, and constraining the uncertainty in the subsurface characterisation.

This project aims to assess model sensitivity to the geological interpretation in simulating groundwater dynamics that represent regions of groundwater flooding. It accounts for uncertainty in the subsurface information to develop an ensemble of different geological interpretations and evaluate the influence of the subsurface characterisation on groundwater flow model performance, within the Ouseburn watershed in the greater Newcastle upon Tyne area.

How to cite: Ntigkakis, C., Birkinshaw, S., Stirling, R., and Thomas, B.: Urban hydrogeologic uncertainty characterisation to evaluate risk of groundwater flooding, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8391, https://doi.org/10.5194/egusphere-egu24-8391, 2024.

EGU24-8476 | Orals | ITS1.5/NP8.6

Subsurface in territorial soil desealing strategies 

Cecile Le Guern, Fabien Prézeau, Pierre Chrétien, and Blandine Clozel

Desealing appears as an option to disartificialise soils. It embraces several territorial issues like water management, adaptation to climate change, the well-being of inhabitants and biodiversity. In practice, many desealing operations are carried out. The areas to be desealed are most often linked to opportunities such as development projects or target actions (like school playgrounds). There are in fact few potential maps to support desealing strategies. Existing methods systematically take certain criteria into account (e.g. water infiltration). Environmental criteria are however more or less considered.

The DésiVille project (2021-2024) aims to provide decision-making tools to support desealing strategies. In particular, it is preparing a methodological guide to map the potential for desealing, in order to propose a harmonized and concerted framework. The methodology considers 4 thematics: i) the characteristics of the sealed surfaces, ii) the potential of infiltration of soils, iii) the environmental risks and the protection of resources, and iv) the benefits of desealing.

The thematics linked to the potential of infiltration of soils and to the environmental risks consider information on the subsurface. In particular the presence of clay and the groundwater depth feed the potential of infiltration. The environmental risks and protection of resources integrate the presence of soluble rocks, the risk of soil pollution, the risk of flooding due to groundwater rise, the geotechnical risk, area of protection of the water resource. A multicriteria spatial analysis crosses the information per thematic on one side, and among thematics on the other side. The study case of Nantes Métropole (France) illustrates the influence of the potential of infiltration and of the environmental risks and protection of resource on the global potential of desealing maps.

The subsurface needs to be considered to build desealing strategies. More generally, it is essential to consider it in urban planning and development. Although out of sight, it must not be out of mind.

How to cite: Le Guern, C., Prézeau, F., Chrétien, P., and Clozel, B.: Subsurface in territorial soil desealing strategies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8476, https://doi.org/10.5194/egusphere-egu24-8476, 2024.

EGU24-8492 | Posters on site | ITS1.5/NP8.6

The subsoil of the city of Naples: accomplishment of a digital platform for its representation, management and protection 

Paolo Maria Guarino, Antonino Barba, Fausto Marra, Fabio Pascarella, and Mauro Roma

Naples is the third largest Italian city by size and population. Over 75% of its area is urbanized and the development of the city, often disorderly over the centuries, have occurred despite that the city is exposed to numerous geological hazards, namely: the volcanic and seismic hazard associated with a possible reactivation of Vesuvius and Phlegraean Fields volcanic centres; the seismic hazard connected with the  Apennine seismic activity; the landslide hazard due to the geologically immature landscape and the sinkhole hazard associated with the anthropic use of the subsoil. The studies undertaken and commissioned in the past by the Municipal Administration of Naples, starting from those aimed at facing the so-called Naples’ Subsoil Emergency in the early 2000s, have allowed the acquisition of a large amount of geological information relating to the subsoil, which requires a new and more modern data management structure. For this purpose, the Ufficio Servizio Difesa Idrogeologica del Territorio of the Municipality of Naples has started a project aimed at valorising and updating the enormous amount of data in its possession, through the creation of an digital platform aimed at representing the subsoil of the municipal territory. In this work the preliminary results of the project are presented. The objective of the project is to build a dataset of the geological subsoil information, structured by means of a system of coherent and organic relationships, which will concern not only the geological features (stratigraphic logs, geotechnical parameters etc.) but also the anthropic features (man-made cavities, underground services, tunnels etc.) and that will be included, in the future, within a broader digital  platform concerning the housing and underground public facilities. ISPRA, via the Department for the Geological Survey of Italy, has carried out numerous studies in the Neapolitan area in recent years, also in collaboration with the Municipality of Naples. In this context, ISPRA will provide scientific support and data in its possession for the construction of an updated geological model of the subsoil and the revision of the city’s geological map. With the accomplishment of the project, the digital platform of the subsoil of the city of Naples will become the reference geo-informatics tool of the municipal GIS; it will also have a strong participatory value open to all stakeholders, with the possibility of activating exchanges between citizens and institutions aimed at a continuously updating the acquired knowledge.

How to cite: Guarino, P. M., Barba, A., Marra, F., Pascarella, F., and Roma, M.: The subsoil of the city of Naples: accomplishment of a digital platform for its representation, management and protection, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8492, https://doi.org/10.5194/egusphere-egu24-8492, 2024.

EGU24-8678 | ECS | Posters on site | ITS1.5/NP8.6

Remotely sensed monitoring of urban greening in China from 1990-2019 to support SDG11 

Ping Zhang, Hao Wu, Hao Chen, and Qiangqiang Sun

Understanding and accurate identification of long-term urban greening dynamics in China are critical for the sustainable urban management (Sustainable Development Goals, SDG11) and living environment of humans. But it was often challenging because a lack of continuous high-frequent data at high spatial resolution and over large time scales. Here, we proposed a framework for identifying detailed evolution processes and regime shifts in relation to urban greening based on characterization of urban greenness in continuous fields over space and time. We utilized annual, fractional estimates of urban green vegetation (GV) endmember time series from per-pixel Landsat composites, using a standardized spectral mixture Vegetation-Impervious surface-Soil (VIS) model in China over the past three decades. A Google Earth Engine platform-based non-linear model (logistic curves) was developed to derive the magnitude, timing and duration of urban greening at a per-pixel basis during these time series records. These parameters were combined to characterize heterogeneous pattern of urban greening throughout the entire China in 1990-2019. We found that the unmixed fractions of urban GV exhibited a generally consistent agreement with estimated fractions from high-spatial-resolution Google earth images (RMSE =11.30%), demonstrating its high suitability and reliability. Using detailed geographic process model with logistic trajectory fitting curves, our findings indicate that the ratio of the area with significant greening trends during 1990-2019 account for nearly 3.0% to the overall urbanized area in China. These greening changes are predominantly distributed in eastern coastal region and northeast Plain. In particular, the Jing-jin-ji, Ha-Chang and Middle-Southern Liaoning are the top three urban agglomerations contributing the greening for this period. Notably, Urumqi, the capital city in north-western China, has the highest ratio of the area with significant increasing GV relative to the urbanized space of the entire city, due to great achievements of urban green construction (i.e., the newly established parks or street plants), and relatively low greenness before 1990. Based on the derived change parameters, our results also reveal the economic impacts on the timing of urban greening are prevalent. For instance, the timing of turning points for urban greening in three major highly-urbanized and developed urban agglomerations, that is, the Jing-jin-ji, Yangtze River Delta, Pearl River Delta showed 2-3 years earlier than other regions. Compared to the state-of-the-art approaches, this framework has the potential to detect high-frequent urban greening process as continuous spatial and time fields with multi-dimensional thematic, thus could help support sustainable urban management practices.

How to cite: Zhang, P., Wu, H., Chen, H., and Sun, Q.: Remotely sensed monitoring of urban greening in China from 1990-2019 to support SDG11, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8678, https://doi.org/10.5194/egusphere-egu24-8678, 2024.

EGU24-9413 | ECS | Orals | ITS1.5/NP8.6

Enhancing Building Height Estimation through Occlusion Reduction with Advanced Deep Learning Models 

Yizhen Yan, Bo Huang, Weixi Wang, Linfu Xie, Renzhong Guo, and Yunxiang Zhao

Building heights play a crucial role in various urban research fields, including 3D modeling, urban environmental analysis, sustainable development, and urban planning and management. Numerous methods have been developed to derive building heights from different data sources, including street view imagery, which offers detailed, ground-level perspectives of buildings. However, occlusions from street elements such as trees and vehicles present significant challenges, especially in densely built or complex urban areas. To address this challenge, we propose the use of advanced deep learning models for occlusion reduction, enhancing building height estimation from street view images. As trees typically cause the most occlusion, we employ an open-set detector and a large segmentation deep neural network to create tree masks in the images. Subsequently, we use a stable diffusion model for image inpainting, restoring parts of buildings occluded by trees. These inpainted images are then processed through building instance segmentation, yielding clearer building boundaries for height estimation. Moreover, we integrate a single-view metrology-based height estimation method with a building footprint auxiliary approach, leveraging their respective strengths and mitigating the impact of varying distances between street view cameras and buildings. Our methodology is validated using a dataset comprising 954 buildings and 3814 images. Experimental results demonstrate that our approach increases the percentage of height estimates within a two-meter error margin by approximately 7%, confirming its effectiveness. This work offers a cost-effective solution for large-scale building height mapping and updating, and it opens new avenues for urban research requiring accurate building height data.

How to cite: Yan, Y., Huang, B., Wang, W., Xie, L., Guo, R., and Zhao, Y.: Enhancing Building Height Estimation through Occlusion Reduction with Advanced Deep Learning Models, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9413, https://doi.org/10.5194/egusphere-egu24-9413, 2024.

EGU24-9711 | Orals | ITS1.5/NP8.6

GeoSciences IR: a geological research infrastructure for land management in urban areas 

Luca Guerrieri, Marzia Rizzo, and Roberto Passaquieti

A full access to high-quality geological data is fundamental to address all different aspects of land management, such as adapting to existing geohazard and ensuring the availability of georesources (e.g. critical raw materials and geothermal energy). This is particularly relevant in urban areas, where a multidisciplinary and integrated approach to diverse geological issues is imperative.

GeoSciences IR is a geological research infrastructure currently being implemented through NextGenerationEurope funds, with the aim of meeting the needs of Regional Geological Surveys (RGS), the local technical offices having a specific mandate on geological topics at regional and local level, including the urban environment.

Through the GeoSciences IR platform, it will be possible to access data, services, tools, and training modules developed in accordance with the FAIR principles and the INSPIRE Directive, which require fully open accessibility, interoperability, and reusability.

The priority topics of GeoSciences IR have been selected according to the RGS'needs and encompass various geological themes, including 2D and 3D geological mapping, marine geology, geoheritage conservation, geohazard mapping and monitoring, sustainable mining, and land consumption.

Among datasets under preparation, some will be of more specific interest for the urban environment, including i) stratigraphies from boreholes; ii) characterization of local geohazard related to landslides, sinkholes, active and capable faulting; iii) structural works for the mitigation of hydrogeological risk; iv) ground motion mapping and monitoring for low-velocity slope movements and subsidence; v) soil sealing and land consumption monitoring.

Users will also benefit from the full interoperability among services and will be able to access innovative tools based on specific algorithms available for cloud data processing.

Furthermore, a specific section of GeoSciences IR will be dedicated to e-learning modules built to increase the transfer of knowledge from scientists to end-users of GeoSciences IR. These modules have mainly focused on the methodological approach for data collection and on the use of available datasets and tools.

GeoSciences IR is under implementation by a large consortium composed by 13 Italian universities and 3 research institutes, coordinated by ISPRA, Geological Survey of Italy. The infrastructure will open to the public in 2025 and will be maintained for at least 10 years.

In this long-term perspective, a dialogue with external stakeholders (from institutions and the private sector) has already started with the aim of building a reference infrastructure for geological data in Italy, taking into account also their feedback and, in some cases, including additional contributions in terms of data, services and tools. Meanwhile, a constant interaction has been established with other existing research infrastructures available at European level (e.g. EPOS ERIC, EGDI) to ensure their complementarity and identify eventual gaps and overlaps.

How to cite: Guerrieri, L., Rizzo, M., and Passaquieti, R.: GeoSciences IR: a geological research infrastructure for land management in urban areas, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9711, https://doi.org/10.5194/egusphere-egu24-9711, 2024.

EGU24-11021 | ECS | Orals | ITS1.5/NP8.6

Simulating Temperature and Evapotranspiration using a Universal Multifractal approach 

Arun Ramanathan, Pierre-Antoine Versini, Daniel Schertzer, Ioulia Tchiguirinskaia, Remi Perrin, and Lionel Sindt

Abstract

Temporal structure functions are usually defined as the q-th order statistical moment of the absolute fluctuation in a time series over a temporal lag at a given resolution. However, applying this in analyzing a temperature time series results in the possibility of simulating only a similar fluctuation over a temporal lag at a resolution and not the temperature directly. Since the aim is to simulate a temperature time series this simulated fluctuation series can be added to an assumed mean temperature to obtain a temperature time series. However, proceeding this way seems to necessitate some ad-hoc moving average technique that seems difficult to be physically reasoned. Secondly but more importantly both diurnal and seasonal periodicity have to be forcibly introduced once again in a non-rigorous manner. A drastic yet reasonably useful alternative would be to modify the definition of the structure-function instead. For order of statistical moment q  the modified structure function is now defined here as

Sq(Δt)=⟨ΙTλ - Tλ/2,2Ιq

Where the scale ratio λ∝1/ΙΔtΙ; 2m/2m=1≤λ≤Λ=2m/20 and ΙΔtΙ is the time lag, whereas 2m is the largest possible scale out of the scales analyzed that can be represented as a power of 2. While Tλ is the temperature at scale ratio λ or scale l, Tλ/2,2 is the upscaled (by a scale ratio of 2) temperature at scale ratio λ/2 or scale 2l, and the subscript ‘2’ indicates that each element of  Tλ/2 (upscaled temperature) is repeated twice consecutively. It should be noted that Tλ/2,2 is not the same as Tλ because the former is an upscaled series, twice repeated (consecutively) of the latter. The largest scale ratio considered in the analysis is Λ. By defining the structure-function in this way temperature at a larger scale after being repeated a sufficient number of times can be directly added to the fluctuation at a smaller scale to result in the temperature at a smaller scale. The universal multifractal parameters obtained from the modified structure-function analysis are not necessarily equal to those obtained from the usual structure-function analysis (i.e. the two different structure functions follow two different scaling laws). An iterative curve fitting technique is used to estimate the values of Universal Multifractal (UM) parameters C1, H, and a  while the value of α  is estimated using a normalized form of the modified structure function along with the un-normalized one. A simulation procedure that utilizes the aforementioned modified structure function definition is proposed here to generate temperature scenarios. Finally, reference evapotranspiration is estimated based on the simulated temperature using a simple empirical power law function. The actual evapotranspiration is estimated using the reference evapotranspiration and water content via a different, simpler empirical function. The tentative methodology proposed here when used along with simulated reference rainfall scenarios could help design zero-emission green roof solutions.

 

Keywords

Multifractals, Non-linear geophysical systems, Cascade dynamics, Scaling, Hydrology, Meteorology.

How to cite: Ramanathan, A., Versini, P.-A., Schertzer, D., Tchiguirinskaia, I., Perrin, R., and Sindt, L.: Simulating Temperature and Evapotranspiration using a Universal Multifractal approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11021, https://doi.org/10.5194/egusphere-egu24-11021, 2024.

EGU24-13309 | ECS | Orals | ITS1.5/NP8.6 | Highlight

Urban energy futures: Unraveling the dynamics of city-scale building energy use and CO2 emissions under mid-century scenarios 

Chenghao Wang, Janet Reyna, Henry Horsey, and Robert Jackson

Residential and commercial buildings jointly account for 39% of energy consumption and 28% of greenhouse gas emissions in the U.S. In densely populated urban areas, the share of energy use and emissions attributable to buildings can be even higher. The future evolution of building energy use and associated carbon emissions is uncertain, with potentially substantial variations in climate conditions, socioeconomic development, and power sector trajectories; accounting for these in future projections is often compounded by limited data availability and resolution of conventional modeling approaches. To address these challenges, in this study, we employed a bottom-up, high-resolution modeling approach and evaluated city-scale building energy consumption and CO2 emissions across 277 urban areas in the U.S. under various mid-21st century scenarios. Our findings reveal substantial spatial and temporal variations in future changes in building energy use and CO2 emissions among U.S. cities under a variety of climate, socioeconomic, and power sector evolution scenarios. On average, a 1°C warming at the city scale projects a 13.8% increase in building energy use intensity for cooling, accompanied by an approximately 11% decrease in energy use intensity for heating, albeit with notable spatial disparities. Collectively, driven by global warming and socioeconomic development, mid-century city-level building energy use is projected to rise on average by 17.5–39.8% under all scenarios except for SSP3-7.0 when compared with the last decade. In contrast, city-level building CO2 emissions are projected to decrease in most urban areas (averaging from 10.6% to 66.0% under different scenarios), with spatial variations primarily influenced by climate change and power sector decarbonization.

How to cite: Wang, C., Reyna, J., Horsey, H., and Jackson, R.: Urban energy futures: Unraveling the dynamics of city-scale building energy use and CO2 emissions under mid-century scenarios, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13309, https://doi.org/10.5194/egusphere-egu24-13309, 2024.

EGU24-14334 | Orals | ITS1.5/NP8.6

Realtime monitoring of urban flooding by ensemble Kalman filters 

Le Duc, Juyoung Jo, and Yohei Sawada

Urban drainage models have been used in many cities for analysis, prediction, and control related to urban flooding. Many sources of uncertainties exist in these models comprising model parameters, meteorological forcings, and surface conditions. Thus, it is necessary to calibrate models before using them in reality. A common choice in calibration is to fit the model outputs with observations through many cases. This strategy is known as the offline mode in calibration and works on the stationary assumption of model parameters. If parameters vary in time, this method usually yields the climatological range of the parameters, which are not necessarily optimal in specific cases. In this study, instead of the offline model we follow the online mode in estimating model parameters by using an ensemble Kalman filter (EnKF). Furthermore, we estimate not only model parameters but also model states simultaneously utilizing the EnKF. Note that originally, EnKF is a data assimilation technique that is based on sampling in estimating any system states given observations, and later is used for the purpose of parameter estimation. The combination of EnKF and an urban drainage model is expected to lead to a real-time monitoring system for urban flooding similar to reanalysis systems in numerical weather prediction.

How to cite: Duc, L., Jo, J., and Sawada, Y.: Realtime monitoring of urban flooding by ensemble Kalman filters, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14334, https://doi.org/10.5194/egusphere-egu24-14334, 2024.

EGU24-14606 | ECS | Orals | ITS1.5/NP8.6

A cross-scale methodological framework for the quantification of the impact of urban features on intra-city microclimate 

Xiaotian Ding, Yongling Zhao, Dominik Strebel, Yifan Fan, Jian Ge, and Jan Carmeliet

Evaluation of the outdoor thermal comfort and comprehension of the impact of urban morphology are essential for assessing heat-related risks and implementing urban planning strategies that enhance the resilience of urban populations to extreme heat events. However, the challenge lies in achieving city-wide thermal comfort mapping at high spatial and temporal resolutions, which requires consideration of the complex urban morphology (urban geometry and land cover) at a microscale, as well as the background meteorological factors at larger scale. Here, we introduce an effective framework for city-scale thermal comfort mapping at high spatial-temporal resolution that integrates WRF-UCM and SOLWEIG model, aiming to achieve fine-grained thermal comfort mapping at the city scale and to explore the impact of urban morphology on these thermal conditions.

In the proposed framework, we employ the WRF-UCM model (The Weather Research and Forecasting model coupled with the urban canopy model) to establish the background meteorological condition at local-scale (500m resolution). Additionally, we utilize the SOLWEIG (Solar and Longwave Environmental Irradiance Geometry) model for the simulation of mean radiant temperature at a finer micro-scale (10m resolution), a critical determinant of thermal comfort. These simulations are performed using detailed 3D urban morphological data and land cover information. Subsequently, the Universal Thermal Climate Index (UTCI) is calculated on hourly basis, integrating the aforementioned factors.

A case study conducted for a Chinese city with a population of 15 million demonstrates a significant correction between the rise in the UTCI during daytime and an increase in impervious surface area, evidenced by a maximum correlation coefficient of 0.80. Furthermore, our findings emphasize the significance of tree canopy coverage in mitigating heat, demonstrating that an implementation of 40% tree cover could diminish daytime UTCI by approximately 1.5 to 2.0 ºC. This methodological framework is not only instrumental in assessing heat-related risks and human thermal discomfort within intricate urban environments but also offers pivotal insights for the adoption of climate-resilient urban planning strategies.

How to cite: Ding, X., Zhao, Y., Strebel, D., Fan, Y., Ge, J., and Carmeliet, J.: A cross-scale methodological framework for the quantification of the impact of urban features on intra-city microclimate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14606, https://doi.org/10.5194/egusphere-egu24-14606, 2024.

Urban areas are major contributors to climate change, accounting for 71 to 76% of CO2 emissions from global final energy use [1]. Nevertheless, cities are growing in both size and number. By 2030, it is projected that 730 million people will live in megacities (cities with at least 10 million inhabitants) compared to 500 million people in 2016 [2]. The number of megacities will also increase from 29 to 43 [3]. On the other side, solar radiation is an important component in the energy balance of urban areas. Urban form impacts the production of building-integrated photovoltaics, solar heat gains and heating/cooling demand of buildings. Relevant urban form characteristics include urban layout, population density, and individual building characteristics, such as height, wall orientation, roof slope, and construction material. Optimization of the urban form design can contribute to better energy performance of buildings. However, optimization is a large multivariable problem that is computationally intensive. A good understanding of the urban form impact can guide the optimization. In this work, the influence of shadow from surrounding buildings on solar radiation incident on buildings is studied provided a three-dimensional (3D) model of an area.

Open Access 3D models for many cities are made available by local authorities. Standardized data formats for 3D modelling are well-established. The scientific community has been working towards understanding urban forms, their impact on energy demand, and the potential for realizing sustainable urban forms. So far, the available work relied on different tools to analyze the impact of urban form on space heating/cooling demand for a specific city making reproducibility difficult. 

This work shows the advantage of using the standardized CityJSON format to establish an open-source Python-based framework to calculate hourly solar irradiance on building facades, considering the shadow of surrounding buildings, generate a thermal model of building envelopes, and calculate heat losses, gains, and the heating load of a building. The proposed methodology involves three phases. First is data collection and pre-processing. Second is the calculation of direct solar radiation on building facades and roofs. For that, hourly sun positions have been determined.  Maximum shadow length is calculated for each sun position. The geometry of buildings is analyzed, shared walls are excluded, and exemplary window vertices are allocated on the free walls such that the window-to-wall ratio ranges between 15% and 25%. Orientations of walls and slopes of tilted roofs were identified. Hyper-points are deployed on each surface in a 0.5m grid. With that, shadow height at each hyper-point and direct solar radiation were calculated. Third is the estimation of the heating or cooling load.

An exemplary neighborhood in Munich is presented as a real case study. Preliminarily results confirm that urban form is influencing the energy performance of buildings. Less shadowing on a building implies higher solar exposure but not necessarily reduced heating demand despite identical thermal properties of buildings’ envelope.

 

 

References:

[1] United Nations. (2017). Urban Environment. https://unfccc.int/resource/climateaction2020/media/1308/Urban_Environment_17.pdf

[2] United Nations. (2016). The World’s cities in 2016: data booklet. http://digitallibrary.un.org/record/1634928

[3] European Commission. (2020). Urbanisation worldwide. https://knowledge4policy.ec.europa.eu/foresight/topic/continuing-urbanisation/urbanisation-worldwide_en

How to cite: Alfouly, M. and Hamacher, T.: Evaluating Urban Form Influence on Solar Exposure and Corresponding Building Energy Demands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15532, https://doi.org/10.5194/egusphere-egu24-15532, 2024.

EGU24-15561 | Orals | ITS1.5/NP8.6

How do geological surveys respond to evolving uses and interaction in the urban subsurface? 

Tim Kearsey, Stephanie Bricker, Ricky Terrington, Holger Kessler, Helen Burke, and Steve Thorpe

The UK Government Office for Science has recently commissioned a Foresight Project on the ‘Future of the Subsurface’. The project draws on experts across different government departments and industry - including representative from the geological and environmental community, planning specialists, infrastructure and service providers, city authorities and energy specialists - to understand the future demands that will be placed on the subsurface to deliver our sustainable development goals; What are the high-value future societal subsurface uses? What climatic and environmental pressures are expected? What policy interventions will be required to protect and enhance the value of the subsurface in the longer-term? We present outcomes from the Foresight project's subsurface issues paper, alongside recommendations from the National and Regional level expert elicitation. Drawing on our research in urban geosciences and subsurface assessment we highlight how geological surveys can, and are, responding to the issues and recommendations highlighted by the Foresight project.  Some common themes emerge for which the geological survey has a role, for example, ensuring coordinated and interdisciplinary approaches to planning; Assessing opportunities to update or streamline subsurface governance and regulation; Improving the coverage, quality, availability and interoperability of data.

In addition to these overarching principles, the variability of regional geology in the UK and its impact on subsurface issues is a prominent outcome of the Foresight project and necessitates place-based approaches, tailored to distinct geologies and geographies, to define a hierarchy of subsurface need.  The UK has a particularly varied geology spanning the whole Phanerozoic this means that there are very different geological problems in different cities. Taking this placed-based approach we show how the evolution of 3D geology mapping and geospatial tools at the British Geological Survey (BGS), has shifted towards multi-assessment to appraise the diverse integrated and competing subsurface uses. We highlight the practical applications of 3D models in improving data availability and accessibility e.g. by updating geological maps, enhancing data products, and facilitating user accessibility through tools like model viewers. The paper concludes by emphasizing the importance of geological information to help facilitate dialogue and stakeholder consultation, and support evidence-based policymaking.

How to cite: Kearsey, T., Bricker, S., Terrington, R., Kessler, H., Burke, H., and Thorpe, S.: How do geological surveys respond to evolving uses and interaction in the urban subsurface?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15561, https://doi.org/10.5194/egusphere-egu24-15561, 2024.

EGU24-16662 | Orals | ITS1.5/NP8.6 | Highlight

Different Approaches to the Impacts of Climate Change, with a Common Goal: a Healthy Planet 

Ioulia Tchiguirinskaia, Yangzi Qiu, and Daniel Schertzer

This work has benefited from a multidisciplinary scientific and technical contributions geared by the HM&Co Lab of the Ecole des Ponts ParisTech (hmco.enpc.fr) towards the sustainable, desirable, and resilient city. The deepening of the Universal Multifractal (UM) concepts and the encouragement of their operational applications have been linked to several initiatives launched in recent years to better integrate the heterogeneity/intermittency into public policy practices. Considering the complex, dynamic interactions between geophysical and anthropogenic fields within a conurbation such as the Ile de France region, a transition towards the shared value economy has been considered to best stimulate sober and collaborative development, and there exist at least 3 ways to approach today’s discussions about future transformations. Their intercomparison is the core of this presentation.

Following the United Nations 2030 Agenda, the first most conventional approach is based on notions of sustainable development, supported by appropriate adaptation and mitigation of climate change.

Combining the notions of extreme variability and complexity would require linking together geophysical and urban scales within extreme variability, and therefore considering geosciences, and not just geophysics! Such a synergistic and integrative approach would help move beyond traditional silo thinking, addressing the complexity of data- and/or theory-driven urban geosciences.

Finaly, combining the notions of scaling and nonlinear variability would ultimately require linking cascades, multiplicative chaos, and multifractals. This would initiate a break with linear stochastic models towards stronger heterogeneity / intermittency, which would in turn lead to a plausible clustering of field and activity fluctuations. The appearance of multifractal phase transitions then becomes possible, considerably amplifying the impact of any action, and would make future transformations fully efficient, effectively imitating the way in which Nature acts. This will be finally illustrated using several examples of so-called Nature Based Solutions (NBS).

How to cite: Tchiguirinskaia, I., Qiu, Y., and Schertzer, D.: Different Approaches to the Impacts of Climate Change, with a Common Goal: a Healthy Planet, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16662, https://doi.org/10.5194/egusphere-egu24-16662, 2024.

EGU24-17225 | Orals | ITS1.5/NP8.6

Geophysics for urban subsurface characterization: Two case studies from Spain 

Beatriz Benjumea, Carlos Marín-Lechado, Beatriz Gaite, Ana Ruíz-Constán, Martin Schimmel, Fernando Bohoyo, and Zack J. Spica

This work focuses on two case studies carried out in Spain, where urban geophysics plays an important role in subsurface characterization. The application of geophysical methods in urban scenarios faces several challenges related to environmental noise (seismic or electromagnetic) or logistical constraints (lack of open space, complexity of instrumentation setup). In order to overcome these problems, research efforts are needed on both acquisition and processing aspects. The first case study presents the use of an innovative technology to acquire seismic data in the city of Granada. Distributed Acoustic Sensing (DAS) is based on the measurement of strain rate along a buried optical fiber that provides seismic measurements in a dense array of sensors. In our study, the fiber is a pre-existing underground telecommunications cable that crosses the city from northwest to southeast. We used 10 hours of ambient noise recordings to obtain subsurface reflection images that provide critical information for ground motion studies and seismic hazards in the metropolitan area. The second case study is located in the autonomous city of Melilla (North Africa). In this work, a gravimetric survey was carried out over the urban area with the aim of delineating the bedrock using 3D gravimetric inversion. We integrated the resulting geophysical model with surface geological observations, electrical resistivity tomography sections and borehole data to produce a 3D geological model of the city. Both studies highlight the suitability of geophysical information to complement the urban geological and geotechnical dataset to characterize and image the city underground.

How to cite: Benjumea, B., Marín-Lechado, C., Gaite, B., Ruíz-Constán, A., Schimmel, M., Bohoyo, F., and Spica, Z. J.: Geophysics for urban subsurface characterization: Two case studies from Spain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17225, https://doi.org/10.5194/egusphere-egu24-17225, 2024.

EGU24-18514 | ECS | Posters on site | ITS1.5/NP8.6

Modeling the Interplay between Urban Environmental Characteristics and Cyclist Route Preferences 

Pranav Pandya, Maider Llaguno-Munitxa, Martin Edwards, Emilie Lacroix, and Gabriele Manoli

As cities grapple with the multifaceted challenges posed by climate change, the Brussels Capital Region (BCR) stands at the forefront of fostering sustainable urban mobility, particularly through the development of cycling infrastructure aimed at bolstering public health and well-being. Policy initiatives implemented in BCR such as 'Good Move' and 'Ville 30' have acted as catalysts, prompting a paradigm shift towards specialized cycling lanes and facilities, thereby enhancing the safety and convenience of cycling as a viable transportation alternative. However, the growing recognition of urban heat stress and thermal discomfort as significant public health concerns, particularly for users of urban soft mobility means, highlights the pressing need for immediate and targeted interventions from urban stakeholders. While it is widely recognized that weather conditions, especially during very hot and cold days, influence cycling behavior, as do urban environmental features like the urban fabric and the presence of green infrastructure in a street, there remains a need to establish quantifiable metrics for assessing the impact of thermal comfort on cycling behavior. This study aims to address this gap, offering a nuanced examination of the cycling routes and cycling behavior of the BCR. We propose a multidisciplinary approach that integrates geospatial, psychological, and environmental sciences to examine the complex interplay between cycling path planning, urban design, micrometeorology, and thermal comfort. Data spanning from 2019 to 2022 has been sourced from multiple channels, including Brussel Mobility, Google Street View (GSV) with semantic image classification, Local Climate Zone (LCZ) maps, and meteorological stations. Geospatial data for Elsene and Etterbeek has been collected. The initial findings reveal that creating green pathways in urban areas can lessen heat stress and enhance comfort for cyclists. Moreover, cyclists are inclined to steer clear of extremely hot or cold weather conditions. Integrating urban microclimatological conditions into the framework of urban cycling design, this research aims to steer policy development towards creating urban soft mobility solutions that are more comfortable, climate-adaptive, and prioritize health considerations.

How to cite: Pandya, P., Llaguno-Munitxa, M., Edwards, M., Lacroix, E., and Manoli, G.: Modeling the Interplay between Urban Environmental Characteristics and Cyclist Route Preferences, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18514, https://doi.org/10.5194/egusphere-egu24-18514, 2024.

EGU24-18610 | Orals | ITS1.5/NP8.6 | Highlight

From paper reports to 3D models for all – Irish geodata in urban settings 

Sophie O'Connor and Beatriz Mozo Lopez

Communicating the subsurface is a challenge. Geoscientists are trained to visualise what is underneath them and to see the subsurface in 3D, whereas planners, policy makers and the people impacted by both (i.e., the public) are not.

Over many years, Geological Survey Ireland has developed several services in different formats to help pull together information about the subsurface, to present it in an organised manner and to portray it in three dimensions. Underpinned by the organisation’s commitment to open data and re-use of public sector information, these services are:

  • National Geotechnical Borehole Database
  • Geotechnical Viewer
  • 3D models and model viewer

Assembled over several decades, the National Geotechnical Borehole Database has expanded with the submission of ground investigations that have been carried out ahead of development projects by the private and public sectors. It acts as a secure, national repository and is a valuable resource for:

  • planning and optimising future ground investigations;
  • understanding the subsurface and urban geology;
  • for helping construct 2D and 3D models.

For ease of access, data and reports from the National Geotechnical Borehole Database are published on the Geotechnical Viewer, freely available to all.  The online Geotechnical Viewer displays ground investigations as digitised, georeferenced polygons, with an associated downloadable report in .pdf format. Several thousands of ground investigations projects are presented.

With time and technical and software advances, Geological Survey Ireland has produced urban 3D geological models using the National Geotechnical Borehole Database. A primary function of these models is visual communication of the subsurface to geoscientists, professionals from other disciplines, researchers, students and members of the public.

Our urban 3D models can assist with:

  • Resource (water and geothermal) mapping;
  • Understanding and characterising urban geology, with potential relevance for basement impact assessment, Sustainable Drainage Systems (SuDS), flooding and, subsurface management;
  • Optimising geotechnical investigation, design and construction;
  • De-risking human activities from impact of our subsurface environment;
  • Investigating impact of human activities on environment around and beneath us, e.g., dewatering;
  • and informing policy, planning, protective and climate adaptation measures.

3D geological models allow everyone to visualise the subsurface and can be used to communicate the geoscience behind policy, thereby making defensible decisions visible. To ensure the 3D models are easily accessible by all, Geological Survey Ireland have a 3D model viewer where no software or zip file downloads are needed. The 3D model viewer has Interactive and Augmented Reality functionality.

Recognising the importance of freely available, accessible data for non-geoscientists, Geological Survey Ireland has created and smoothed pathways for stakeholders to access and visualise geological data in urban settings.

How to cite: O'Connor, S. and Mozo Lopez, B.: From paper reports to 3D models for all – Irish geodata in urban settings, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18610, https://doi.org/10.5194/egusphere-egu24-18610, 2024.

EGU24-18749 | Posters on site | ITS1.5/NP8.6

Tackling practical challenges in anomaly detection for real-time monitoring of urban waste water networks 

Lennart Schmidt, Felix Weiske, Manfred Schütze, Phillip Grimm, Julius Polz, and Jan Bumberger

Waste water networks constitute a crucial element of urban infrastructure that are influenced by an observed increase in urban flooding events. To ensure regular network operation and minimal environmental impact, anomaly detection of urban waste water networks timeseries can serve as a real-time monitoring tool to detect a) sensor defects and b) system anomalies such as leaks or blockages. However, setting up such a monitoring system in practice can face significant challenges. These include limited amounts of labeled anomalies, heterogenous data quality, inconsistent measurement frequencies as well as instationarity of the system (sensor displacement and drop-out, changes in network layout). For the waste water network of a medium-sized German city, we set up machine learning based anomaly detection and present strategies to tackle aforementioned challenges. Our results show that autoencoder-based model architectures are valuable tools in such a context where only a minimal fraction (<0.01%) of the data is labeled. Both a well-parametrized interpolation strategy and a model architecture that is largely robust to missing values are essential prerequisites for adequate model performance. Based on our results, we derive general strategies to aid in setting up anomaly detection systems in real-world use cases.

How to cite: Schmidt, L., Weiske, F., Schütze, M., Grimm, P., Polz, J., and Bumberger, J.: Tackling practical challenges in anomaly detection for real-time monitoring of urban waste water networks, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18749, https://doi.org/10.5194/egusphere-egu24-18749, 2024.

The urban heat island effect is a well-documented phenomenon in cities, particularly in metropolitan areas, with recognized environmental consequences. Mitigating this effect through urban green space planting strategies has been widely acknowledged. However, the extent of the spatial heterogeneity of the cooling effect across different urban functional zones remains insufficiently explored at a fine scale of urban green space.

In this study, we employed a robust semi-supervised deep learning method to precisely segment urban green spaces from high-resolution remote sensing images and developed a 0.5 m fine-scale urban green space product tailored for the Beijing metropolitan area. Leveraging the fine-grained urban green space segmentation results, we modeled cooling efficiency through a nonlinear relationship, quantified as the temperature reduction for a 1% urban green space cover increase. We also conducted a comprehensive assessment of differential cooling efficacy, considering both reference temperature and urban green space cover levels, across diverse urban functional zones at the scale of 300 m × 300 m urban grids.

The results revealed substantial disparities in cooling efficiency among different urban functional zones and different levels of urban green space coverage in Beijing. To be specific, with a 1% increase in urban green space, the commercial zone, residential zone, industrial zone, transportation zone, and public zone can achieve a cooling effect with a mean of 0.095 ± 0.075°C, 0.075 ±0.065°C, 0.075±0.065°C, 0.070±0.060°C and 0.055±0.045°C respectively. By uncovering spatial variations and heterogeneity in cooling effects, our study underscores the critical need for customized strategies in urban green space planning based on functional zone characteristics and offers valuable insights into urban planning and sustainable development practices.

How to cite: Zeng, Y., Guo, J., and Zhu, X. X.: Differential Cooling Efficacy of Fine-Grained Urban Green Spaces Across Diverse Functional Zones: A Case Study in the Beijing Metropolitan Area, China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18781, https://doi.org/10.5194/egusphere-egu24-18781, 2024.

EGU24-20304 | ECS | Orals | ITS1.5/NP8.6

Asssessing the impacts of extreme rainfall on urban transport: a complex systems approach 

Alistair Ford, Yimeng Liu, Richard Dawson, and Saini Yang

Extreme rainfall causes disruption and damage to urban transport networks through flooding, resulting in economic impacts for residents and businesses. The impact of such extreme weather events is the result of a complex interaction between the hazard (shaped by the nature of the rainfall and urban characteristics such as topography and land-use), exposure (the spatial and temporal intersection of the flood footprint with urban infrastructure and assets), and vulnerability (the ability of those assets and their users to cope with the level of flooding).

This paper demonstrates a complex systems approach to understand the role of these three components of the impact on urban transport systems by dynamically coupling a hydrodynamic flood model (such as CADDIES 2D or CityCAT) with an agent-based transport model (SUMO). By simulating a range of extreme rainfall events at a range of times of day, the modelling approach allows quantification of the scale of the impact (both direct and indirect) and assessment of adaptation options to reduce the disruption. Inclusion of coupled dynamic models allows the exploration of both hard, including engineered and nature-based approaches, and soft measures such as early warning and home working. This allows for a more-complete cost-benefit analysis of interventions and understanding of their effectiveness.

The modelling approach is demonstrated for a range of extreme rainfall events on commuting journeys on the road network in the city of Beijing, China. The results show that whilst grey and green approaches to adaptation can reduce the impact of extreme rainfall on the transport network, the benefits of soft measures, such as demand reduction by increased home working, are greater. Such soft measures also have additional co-benefits for reduction in emissions from transport, and potentially a lower implementation cost. Only by considering these interactions in a complex systems approach can such an assessment be undertaken.

 

How to cite: Ford, A., Liu, Y., Dawson, R., and Yang, S.: Asssessing the impacts of extreme rainfall on urban transport: a complex systems approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20304, https://doi.org/10.5194/egusphere-egu24-20304, 2024.

EGU24-20495 | Posters on site | ITS1.5/NP8.6

Giasone: a method to assess sustainability of georesources cultivation 

Gabriele Leoni, Giovanni De Caterini, Marco D'Antona, Stefano De Corso, Claudia Delfini, Marco Di Leginio, Massimo Diaco, Giovanni Finocchiaro, Fiorenzo Fumanti, Luca Guerrieri, Mauro Lucarini, Ines Marinosci, Michele Munafo', Nicolo' Giovanni Tria, and Daniele Spizzichino

The concept of georesources, within the framework of the new environmental strategies of the European Union's (EU) Green Deal, has gained an expanded perspective, beyond the traditional approach linked to the mining industry. Georesources are defined as natural resources or elements of the landscape, physical space, and territory, to which economic, environmental, or social value is attributed. This definition encompasses raw materials, water resources, soil conservation, as well as intangible elements such as geoheritage, natural landscape, and ecosystem balance.

The concept of sustainability integrates with a technical principle that promotes the improvement of land conditions in natural, ecological, social, economic, and cultural terms. This perspective acknowledges that the European territory is the result of millennia of transformations by humans, with activities such as agriculture, land exploitation, and the use of natural resources that have altered environments.

The EU action plan aims to promote sustainability as a central element of economic growth, guiding capital flows towards a more sustainable economy. A priority is to define a classification of sustainability for georesources cultivation, based on technical-scientific and industrial standards, to which the sustainability of investments in the sector can be referred.

The Green Deal aims to address challenges related to climate change by promoting a new economy based on sustainable development, ecosystem protection, biodiversity conservation, and climate change mitigation. EU economic strategies are oriented towards assigning 'value' to environmental aspects, stimulating innovation and competitiveness in a dynamic market.

The concept of environmental value extends to various areas such as energy efficiency, renewable energy, sustainable agriculture, green mobility, and new technologies. This includes the creation of green jobs to ensure a fair transition to a new sustainable economy and reduced inequalities.

In the context of georesources, traditionally associated with the exploitation of non-renewable and renewable resources, an analytical approach is proposed to assess sustainability not only in the extractive field but also in the context of land planning within a broader geographic context.

For the quantitative assessment of the value of georesources in the policies outlined in the Green Deal, a parametric method based on the integrated analysis of the following themes is proposed: Geography, Hydrography, Environment, Sociology, Nature, and Economics to characterize the intrinsic value of georesources.

The use of GIS as a multidisciplinary analysis tool for integrating environmental and socio-economic data allows for a dynamic approach in identifying the intricate relationships of various themes, simplifying the representation of land status.

For each area identified through the comparison of indicators, a "georesource sustainability" index - the GIASONE index - is calculated by a weighted sum of the indices related to each theme. The use of the parametric method also allows for the comparison of different scenarios under varying environmental and socioeconomic conditions, useful for planning decisions.

How to cite: Leoni, G., De Caterini, G., D'Antona, M., De Corso, S., Delfini, C., Di Leginio, M., Diaco, M., Finocchiaro, G., Fumanti, F., Guerrieri, L., Lucarini, M., Marinosci, I., Munafo', M., Tria, N. G., and Spizzichino, D.: Giasone: a method to assess sustainability of georesources cultivation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20495, https://doi.org/10.5194/egusphere-egu24-20495, 2024.

Recently, we have seen an increase in models that combine powerful technical simulations with efficient visualizations and user interfaces that support decision-making in environmental and urban policies. These tools, known as Digital Twins (DTs) have been currently applied to water management and cities, however, their use tends to be limited to reduced groups of technical experts, policymakers and city officials, with the models behind these tools not being openly available, even though they may be publicly funded. Simultaneously developers, who may be interested in using these models to assess their proposals, cannot access them and must develop their local models, in many cases trying to catch up with new legislation.  A more efficient and open method could be implemented based on sharing evidence-based models through the planning application process. We call this an Integrated Water Planning Portal (IWPP), which consists of a web platform that gives developers access to a water systems model to test their proposals and use this work in the planning application process, which can be done through the same platform. In parallel to this, planners can use the portal to review this work, comment on it or give a final planning verdict. For such a system to work, robust data-sharing and model deployment protocols need to be implemented to strike a balance between accuracy, understandability and data protection. We present work on the feasibility of IWPP, based on prototype development and semi-structured interviews with stakeholders in the UK water management field. Evidence from this work suggests a targeted approach to modelling and data collection which is presented in a model framework. This approach satisfies the requirements of different stakeholders and provides a robust base for further development of tools such as IWPP.

How to cite: Rico Carranza, E.: Integrated Water Planning Portal: Feasibility study for a development-oriented digital twin to facilitate integrated water management through targeted data and model sharing., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20502, https://doi.org/10.5194/egusphere-egu24-20502, 2024.

EGU24-20648 | ECS | Orals | ITS1.5/NP8.6 | Highlight

Current status of the Urban Geo-climate Footprint project 

Azzurra Lentini, Jorge Pedro Galve, Moreno Beatriz Benjumea, Stephanie Bricker, Xavier Devleeschouwer, Paolo Maria Guarino, Timothy Kearsey, Gabriele Leoni, Romeo Saverio, Guri Venvik, and Francesco La Vigna

The Urban Geo-climate Footprint (UGF) project has been developed in the context of the Urban Geology Expert Group of Euro Geo Surveys, aimed to define a new methodology to classify and cluster cities by geological and climatic point of view.

The basic assumption of the UGF approach is that cities with similar geological-geographical settings should have similar challenges to manage, due to both common geological issues and climate change subsoil-related effects. Following this approach, a holistic tool consisting in a complex spreadsheet has been developed and applied to more than 40 European cities, in collaboration with several Geological Surveys of Europe.

It is demonstrated as the Urban Geo-climate Footprint tool is currently capable of providing a semi-quantitative quick representation of the pressures driven by geological and climatic complexity in the analysed cities, providing for the first time such classification for the urban environment.

Through the wide application of this methodology several benefits could be reached as the general awareness increase of non-experts and the enhanced reading-the-landscape capacity of decision makers about the link between geological setting and the increase in pressures due to climate change and anthropogenic activity.

Furthermore, the UGF approach would facilitate the possibility to exchange best practices among similar cities for planning purposes, and it would support the decision processes to define and differentiate policies and actions, also supporting policy and cooperative geoscience and climate justice.

 

How to cite: Lentini, A., Galve, J. P., Benjumea, M. B., Bricker, S., Devleeschouwer, X., Guarino, P. M., Kearsey, T., Leoni, G., Saverio, R., Venvik, G., and La Vigna, F.: Current status of the Urban Geo-climate Footprint project, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20648, https://doi.org/10.5194/egusphere-egu24-20648, 2024.

EGU24-20734 | Orals | ITS1.5/NP8.6

UNDER: Geosystem services underneath for sustainable communities and improved spatial planning practices 

Fredrik Mossmark, Jenny Norrman, Paula Lindgren, Emrik Lundin Frisk, Lorena Melgaço, Marilu Melo Zurita, Victoria Svahn, Tore Söderqvist, Olof Taromi Sandström, and Yevheniya Volchko

Geosystem services (GS) can be defined as the contributions humans derive from the subsurface: the use of the subsurface to build and construct within and on top, groundwater, energy and material extraction, storing of e.g. water, energy and carbon dioxide, providing habitats for diverse species and support for surface life, and serving as an archive of cultural and geological heritage. Sectorial management and lack of consequent consideration of subsurface geosystem services and competing or complementary subsurface uses promote the first-come-first-served principle, potentially hindering a sustainable management of the subsurface and compromising inter- and intra-generational equity. The research project “UNDER: Geosystem services underneath for sustainable communities and improved spatial planning practices” has the overall goal to develop a framework for systematic and structured consideration of geosystem services in Swedish planning practices that can support a path towards sustainable cities and communities. The specific objectives of the UNDER project are to: i) advance the concept of GS by identifying and mapping associated societal values (social, environmental and economic), ii) identify methods to assess societal values and investigate possibilities for integration in existing tools, iii) identify structures of governance and develop a broader and practice-informed understanding of the different societal actors in subsurface planning, and iv) create a participative learning environment, extended beyond the project implementation period leading to transformative processes in planning practice. The project is case study driven and works in collaboration with Swedish municipalities. Four ongoing spatial planning processes in Swedish municipalities have been selected as case studies, which will provide a variety of spatial planning contexts and objectives. The project is a multi-disciplinary, international project with funding from the Swedish research council Formas, running during 2021 - 2025. The presentation of the project will focus on the project activities, preliminary results, and future work.

How to cite: Mossmark, F., Norrman, J., Lindgren, P., Lundin Frisk, E., Melgaço, L., Melo Zurita, M., Svahn, V., Söderqvist, T., Taromi Sandström, O., and Volchko, Y.: UNDER: Geosystem services underneath for sustainable communities and improved spatial planning practices, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20734, https://doi.org/10.5194/egusphere-egu24-20734, 2024.

EGU24-22240 | Orals | ITS1.5/NP8.6

Urban geology as part of 3D city models - challenges and solutions 

Rouwen Lehne, Sonu Roy, Heiner Heggemann, and Christoph Schueth

While 3D city models are now available for many large and medium-sized cities and are increasingly being used, the urban subsurface (= urban geology) continues to be neglected in such models in most cases. The reasons for this are both inhomogeneous and complex geological/hydrogeological information, which at the same time is not assembled in a context-specific way, as well as a lack of standards, interfaces and exchange formats.

To overcome these barriers, geological and hydrogeological 2D and 3D content is currently being elaborated for several urban areas in the federal state of Hesse in close cooperation with the municipal cooperation partners using all available input data (in particular, however, boreholes, geological cross sections and groundwater level measurements), which are being assembled with a view to defined "urban geoparameters".

In addition, an attempt will be made to visualize the urban underground infrastructure (man-made objects) in 3D space and thus bring it into a synopsis with the geological and hydrogeological 2D and 3D content.

The synopsis, in turn, should be carried out in the respective working environments as far as possible, i.e. using the software solutions operated by the cooperation partners. To ensure this, both suitable interfaces and a suitable exchange format are required in the 3D data management systems for geological/hydrogeological models. The OGC API 3D GeoVolume and Styles interfaces and the 3D Tiles exchange format are considered to be the solution here.

With this presentation, we would like to present the current state of work with a focus on the parameterisation and packaging of geological and hydrogeological 2D and 3D data for urban areas.

How to cite: Lehne, R., Roy, S., Heggemann, H., and Schueth, C.: Urban geology as part of 3D city models - challenges and solutions, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22240, https://doi.org/10.5194/egusphere-egu24-22240, 2024.

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