The increasing global demand for nickel, driven by its critical role in stainless steel production and emerging battery minerals technologies, has intensified exploration efforts in geologically diverse terrains. This study focuses on the Cuddapah Basin, a Proterozoic sedimentary basin in southern India, which presents a complex geological framework with promising yet underexplored potential for nickel mineralization. Through an integrated approach combining lithological mapping, geophysical surveys, and geochemical analysis, this paper present fingerprints of geochemical and geophysical signatures to target Nickel Exploration. The preliminary findings indicate the presence of ultramafic intrusions and favourable host rocks such as picritic sills which are typically associated with nickel sulfide deposits. The western margin of the Proterozoic-aged Cuddapah Basin contains gabbro and plagioclase bearing sills within the Tadapathri formations These sills have 4-28% MgO and 30-1050ppm Ni and they are characterized by elevated Th/Nb which is indicative of contamination by upper crustal material. The low MgO mafic magmas have one to two orders of magnitude viscosity higher than the picritic sill they are emplaced all along the Cuddapah basin margin. No Ni-Sulphide mineralization is known in this belt, but trace interstitial sulphide is present. The following features of the Pulivendla-Vemula sill complex indicate that the rocks are prospective for magmatic sulfide exploration:1. Tholeiitic lavas and sills were emplaced during extensional intra-cratonic rifting at a time of major Ni ore formation at ~1.9 Ga metallogenic epoch i.e late Proterozoic-Archaean in age.2. Un-deformed fresh differentiated ultramafic sills have a range in Ni concentration over a narrow interval of forsterite content with primary olivine 3. These sills and other sills in the footprint of regional magnetic and gravity anomalies possibly contain feeders where immiscible magmatic sulfides may have formed. correlating between Werner depth estimations and seismic data, particularly in pinpointing fault zones. These zones act as critical conduits for fluid migration from the mantle to the surface, playing a vital role in both tectonic interpretation and mineralexploration4. Despite the absence of magmatic sulfide mineralization and magmatic breccias, there is untested potential within the basin stratigraphy for the development of intrusions which have a magnetic and density signal, possibly in association with a structural break as well as a diagnostic electromagnetic signal from highly conductive sulfide mineralization. However, the geological complexity, including structural deformation and metamorphic overprints, poses significant challenges in locating economically viable deposits. The study underscores the importance of advanced exploration techniques and multidisciplinary data integration to improve discovery success rates. Ultimately, this work contributes valuable insights into the Ni-mineral prospectivity of the P-V Picritic Sill in western margin of Cuddapah Basin and highlights its potential as a frontier region to relook for nickel exploration in India.

How to cite: Sunder Raju, P. V.: Fingerprints of Nickel Exploration in the Pulivendla-Vemula (P-V) sill in Cuddapah Basin:Geological Complexity and Discovery Potential, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1384, https://doi.org/10.5194/egusphere-egu26-1384, 2026.

Artisanal and small-scale mining (ASM) is an important source of livelihood in Mozambique, directly involving over 100,000 people, largely through informal and poorly regulated operations (Delve, 2020). ASM activities are concentrated in provinces with high mineral potential, including Manica, Tete, Zambézia, Niassa, Nampula and Cabo Delgado (Mapurango, 2014), and primarily involve the extraction of gold, precious and semi-precious stones, as well as construction materials. Despite its socio-economic relevance, the sector is characterised by weak technical organisation, limited regulatory integration and widespread informality.

This study examines the main safety and sustainability challenges associated with ASM in Mozambique, with particular emphasis on occupational health and safety and environmental management. The methodological approach is based on a review of secondary literature and documentary analysis of existing legal and policy frameworks. The analysis indicates that high levels of informality contribute to unsafe working conditions, inadequate use of personal protective equipment, frequent occupational accidents and significant environmental degradation, including soil and water contamination.

Recent regulatory interventions, such as the suspension of mining licences in Manica Province in October 2025 due to uncontrolled discharge of mining effluents, highlight the urgency of strengthening environmental governance and enforcement mechanisms. The results suggest that the adoption of sustainable mining principles—focused on risk management, environmental protection, decent working conditions and long-term economic viability—can substantially improve the performance of ASM operations. Practical measures include basic technical training, increased awareness campaigns on occupational health and safety, gradual adoption of appropriate technologies and progressive formalization supported by effective monitoring.

In conclusion, enhancing safety and sustainability in ASM is essential not only to reduce occupational and environmental risks but also to ensure that small-scale mining continues to positively contribute to local communities and the national economy.

How to cite: dos Santos, L. V. S., Guiliche, M. E., and Mugabe, J. A.: Safety and Sustainability in Artisanal and Small-Scale Mining Operations in Mozambique, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9067, https://doi.org/10.5194/egusphere-egu26-9067, 2026.

How to cite: Touloumenidou, L.: Pumped‑Storage Hydropower in a Post‑Mining Landscapes: A Feasibility Study for Repurposing the Ptolemaida Lignite Basin in Western Macedonia, Greece, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6952, https://doi.org/10.5194/egusphere-egu26-6952, 2026.

Coal is an important major source of energy for sustainable development and growth of economy around the world. Coal fire and mine water issues are two aspects of mining-induced safety and eco-environmental issues which occurred during and after mining. In the present presentation, the author illustrates the understanding of these two issues by employing the theoretic analysis, the experimental simulation, the numerical simulation, and the field investigation, etc. Results from this research show that the rational scientific mining methods and technologies can be used to reduce the occurrence and influence of these two phenomena which leads to the possible sustainable exploitation of coal resource.

How to cite: Zeng, Q.: Coal fire & Mine water: two major post-mining issues, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4291, https://doi.org/10.5194/egusphere-egu26-4291, 2026.

This study evaluates annual changes in wind power density (WPD) in a domain covering the Iberian Peninsula and adjacent areas using several CMIP6 global climate models and the ensemble mean under historical (1961-1990) and SSP5-8.5 scenarios for two-time horizons—near future (2041–2070) and far future (2071–2100).

Results from the ensemble indicate a robust and generalized decrease in WPD throughout the 21st century. The most pronounced declines occur in windows starting mid-century (2050–2055), with reductions of about -90 W m^-2 century^-1 persisting for up to 40-year periods. Short-lived positive trends (≈ 50 W m^-2 century^-1) appear around 2030 and 2045, suggesting temporary peaks before a marked decline (≈ -100 W m^-2 century^-1) in later decades. Comparisons between future and historical periods reveal strong WPD decreases (-70 W m^-2), mainly offshore, particularly in far-future scenarios.

Inland areas may experience annual mean WPD values falling below the cut-in threshold (3 m/s, ≈ 15.5 W m^-2), rendering some older wind farms economically and technically unviable. Offshore regions, despite current technological priorities, face substantial WPD reductions (up to -60 W m^-2), while inland declines are significant in northeastern Spain, where major wind farms are located. These projected reductions—especially offshore (10–20%)—could challenge the financial viability of future wind energy projects.

How to cite: García-Miguel, A., Calvo Sancho, C., Díaz Fernández, J., González Alemán, J. J., López Reyes, M., Bolgiani, P., Martín Pérez, M. L., and Luna, M. Y.: Assessing future wind energy resources in the Iberian Peninsula under climate change scenarios, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6552, https://doi.org/10.5194/egusphere-egu26-6552, 2026.

This study presents a comprehensive methodological framework that integrates micro-scale urban geometry with macro-scale climate projections to improve the assessment of rooftop photovoltaic (PV) potential in urban environments. High-precision solar resource estimation is achieved through the use of very high–resolution Digital Surface Models (DSMs; 0.8 m) within the Solar Energy on Building Envelopes (SEBE) model, enabling detailed simulation of shading effects in dense urban fabrics.

Historical and present-day atmospheric inputs—including surface solar radiation, cloud cover, and aerosol optical depth—are obtained from the Copernicus Atmosphere Monitoring Service (CAMS) and combined with meteorological variables from ERA5-Land. Future rooftop PV potential is projected using a multi-model ensemble of CMIP6 climate simulations under the SSP2–4.5 and SSP5–8.5 emission scenarios. Statistical downscaling techniques are applied to translate large-scale climate projections to local urban conditions.

In addition, the study evaluates PV system performance during specific atmospheric episodes, quantifying the effects of dust intrusions and compound events—defined as the co-occurrence of high temperatures and elevated dust concentrations—on energy yield. Finally, cluster analysis is performed on the urban building stock of selected southeastern Mediterranean cities using key performance indicators, including received solar radiation, total energy yield, rooftop area, and building height.

The results demonstrate that integrating micro-scale urban morphology with macro-scale climate projections is critical for accurately estimating rooftop PV potential, particularly in regions characterized by complex urban structures and climate-sensitive atmospheric processes.

How to cite: Agazarian, N., Cartalis, C., Philippopoulos, K., and Agathangelidis, I.: Integrating Micro-Scale Urban Geometry with Macro-Scale Climate Projections to Improve Rooftop Photovoltaic Potential Assessment: An Application to Selected Urban Areas in the Southeastern Mediterranean, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14485, https://doi.org/10.5194/egusphere-egu26-14485, 2026.

How to cite: Singh, J.: Hierarchical Bayesian Modeling of Solar Irradiance under Extreme Weather in the Tucson Electric Power Region, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22088, https://doi.org/10.5194/egusphere-egu26-22088, 2026.

Wastewater treatment plants are essential environmental infrastructures that operate continuously and require considerable electrical energy, while simultaneously conveying persistent flows that dissipate low-grade hydraulic energy. Recovering even a fraction of this overlooked resource could support decarbonisation targets and provide autonomous power for environmental monitoring and digital water services, without additional land take or large hydropower installations. Within the Horizon Europe project H-HOPE – Hidden Hydro Oscillating Power for Europe – this study investigates how the selection of structural materials affects the performance of vortex-induced vibration energy harvesters (VIV-EH) deployed in controlled water environments. Rather than optimising device geometry or control strategies, the analysis focuses on how broad material classes influence feasibility, energy potential, and environmental suitability when integrating harvesters into existing wastewater infrastructure. Operational records from a municipal wastewater treatment plant in northern Italy were analysed. A validated one-dimensional modelling framework was used as a comparative tool to estimate annual energy production for harvesters manufactured from widely available metallic and composite materials under realistic operating conditions.

Results show a consistent trend: lighter materials with favourable stiffness-to-mass ratios generate larger oscillation amplitudes and substantially higher harvested energy. Fibre-reinforced composites achieve the highest performance, with an estimated annual production of approximately 800–875 kWh/year for the specific case study. Aluminium alloys produce slightly lower yields (≈800 kWh/year) while retaining advantages in recyclability and manufacturability. In contrast, high-density metals such as structural and stainless steel, typically yield 450–480 kWh/year, highlighting how increased mass suppresses the vortex-induced response. These differences arise solely from material choice, without modifying hydraulic conditions, device geometry, or plant operation.

From a renewable-energy perspective, these results indicate that material-driven design is a practical lever for scaling small, autonomous generators across water networks, providing reliable power for sensors, process control and digital water management. Because devices exploit existing hydraulic infrastructure, they can be replicated modularly and integrated alongside other renewables as part of distributed energy portfolios, supporting resilience and local self-sufficiency. However, performance advantages must be considered alongside environmental trade-offs. Composites show limited recyclability and higher embodied energy compared with metals such as aluminium and stainless steel, which favour circularity but offer lower energy conversion. The study relies on a simplified modelling framework and a single representative site, broader validation under different hydraulic regimes and long-term material ageing will require pilot-scale deployment. Despite this, the comparative trends provide robust guidance for design and prioritisation.

Overall, the study demonstrates that targeted material selection can unlock “hidden hydropower” within wastewater systems, delivering incremental yet scalable renewable generation aligned with European decarbonisation goals while enhancing the sustainability and reliability of essential water services.

How to cite: Siviero, M., Guðlaugsson, B., Nascimben, F., Finger, D. C., Benato, A., and Cavazzini, G.: Material Selection for Vortex-Induced Vibration Energy Harvesting in Water Systems: Environmental and Performance Insights from the Verona Case Study in Italy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18202, https://doi.org/10.5194/egusphere-egu26-18202, 2026.

Investment decisions for offshore wind-to-hydrogen (W2H) projects are often framed as “better forecasts reduce uncertainty,” but it is less clear when higher-fidelity scenario modelling meaningfully changes a financing decision versus merely narrowing outcome ranges. We address this question using a decision-coupled evaluation that scores forecast skill on propagated economic distributions and links it directly to financeability metrics.

Using 61 years of ERA5 wind data at 150 m hub height, we generate 1000 synthetic 23-year hourly wind scenarios per method and propagate them through a techno-economic model of a 375 MW offshore W2H project (development in 2024, operation in 2026-2050, base hydrogen price €8/kg, discount rate 7%). We compare three probabilistic scenario generators: historical bootstrapping, parametric Weibull fitting, and a calibrated probabilistic long short-term memory (LSTM) sequence model (used as a benchmark rather than architectural novelty).

We evaluate (a) continuous ranked probability score (CRPS) of levelized cost of hydrogen (LCOH), net present value (NPV), and internal rate of return (IRR), (b) decision bandwidths W(Y) = P₉₅(Y) – P₅(Y), (c) threshold-crossing probabilities P_r(NPV>0) and P_r(IRR>10%), and (d) a local elasticity E(Y) = dW(Y)/dCRPS that maps marginal forecast skill to risk-band compression. Finally, we run a financing price sweep to identify the minimum hydrogen offtake price that achieves a 90% probability target for NPV > 0 and the joint target NPV > 0, IRR > 10%.

Results show that improved scenario modelling can substantially reduce economic distribution error and compress risk bands: the LSTM lowers CRPS by 30% for LCOH and NPV and by 25% for IRR versus the best bootstrap/Weibull configurations. However, under base assumptions the financeability thresholds are nearly invariant across methods: the 90%-target required hydrogen price is €7.76-7.78/kg for P_r(NPV>0) and €9.16-9.18/kg for P_r(NPV>0 and IRR>10%), with cross-method spread below €0.02/kg indicates a threshold-saturated regime where better modelling mainly narrows uncertainty rather than shifting the decision boundary. Sensitivity analysis indicates decision value is highest in moderate-margin regimes (roughly €5.5-8/kg) and diminishes at high profitability where models converge.

This work reframes “better scenarios” into an investment-relevant diagnostic: use elasticity and threshold behaviour to identify when modelling improvements will shift financeability versus only compress risk bands, supporting more defensible screening and policy design.

How to cite: Aditama, P. and Zia, A. W.: When Does Better Scenario Modelling Improve Financeability? A Decision-Coupled Evaluation for Offshore Wind-to-Hydrogen, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5058, https://doi.org/10.5194/egusphere-egu26-5058, 2026.

High wind and solar penetrations would make bulk energy storage increasingly important for electricity system reliability. We introduce a deficit stretch framework that relates the temporal structure of generation shortfalls to optimal storage configurations in a decarbonizing grid and links the intensity, duration, and frequency of deficits to storage needs and cost–reliability trade-offs. Using Karnataka (India) as a case study, we simulate wind–solar–demand scenarios to examine (i) drivers of deficit-stretch emergence, (ii) which wind–solar–storage portfolios align with available storage technologies, and (iii) how these choices map onto Pareto frontiers of cost versus reliability. We cluster deficit stretches to identify characteristic storage durations (across hours to seasons) enabling a direct mapping from variability patterns to feasible technology options. Results indicate that solar share largely controls the deficit stretch duration spectrum. The proposed framework offers an empirical approach leading from analysis of renewables variability to consideration of bulk energy storage portfolios amidst cost–reliability tradeoffs and is extendable to other regions as well.

How to cite: Gangopadhyay, A. and K Seshadri, A.: Designing cost-effective storage portfolios in decarbonizing power systems: a deficit stretch approach, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3742, https://doi.org/10.5194/egusphere-egu26-3742, 2026.

How to cite: Davis, D. and Saraf, N.: Unfolding the rise in cooling demand from residential buildings sector in India, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8851, https://doi.org/10.5194/egusphere-egu26-8851, 2026.

Accurate assessment of ecological vulnerability in island systems under natural and anthropogenic pressures is crucial for ecosystem stability and sustainable development. Constructing an adaptive and scientific framework for evaluating ecological vulnerability in island regions remains a key challenge. This study introduces a novel Pressure–Vigor–Organization–Resilience (PVOR) model for assessing ecological vulnerability, applied to the main island of Malta. A combined weighting approach using game theory was used to determine composite indicator weights, while multi-source data (e.g., remote sensing and geospatial data) were integrated to investigate the long-term spatiotemporal evolution of ecological vulnerability from 2000 to 2020 and its driving factors.

The results show that: (1) Over 20 years, the ecological vulnerability index (EVI) of Malta fluctuated but declined from 0.65 to 0.58. From 2000 to 2015, vulnerable areas were mainly located in the eastern built-up zones. By 2020, the area of highly vulnerable zones decreased by 86% due to ecological protection policies and the COVID-19 pandemic, with minor increases in vulnerability (less than 5 km²) along the southwestern coastline. (2) Ecological vulnerability exhibited significant spatial clustering (global Moran’s I > 0.80, p < 0.01), with high-value clusters in the east and low-value clusters in the west and north. (3) Key driving factors include habitat quality, landscape fragmentation, population density, and development intensity, with interaction effects being stronger than individual factors. (4) Based on both static and dynamic vulnerability assessments, ecological zoning was defined, and targeted management strategies were proposed.

This study provides a scientific foundation for ecological restoration and sustainable development in Malta, offering a transferable framework for other island systems.

How to cite: Wang, L., Chi, J., and Xiao, X.: Spatiotemporal Patterns of Ecological Vulnerability in Malta: An Empirical Analysis Using the PVOR Model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7454, https://doi.org/10.5194/egusphere-egu26-7454, 2026.

An aquathermal energy system is a sustainable heating and cooling technology for buildings by utilizing low-grade thermal energy from water sources. This contribution presents a full scale pilot at the TU Delft campus that investigates and show-cases the potential of a campus pond to supply thermal energy to the Firma van Buiten (FvB) building, which is a restaurant/meeting location.

The contribution focuses on sensor integration and data acquisition, heat balance modeling, and design considerations for an aquathermal system. Initially, a field campaign was conducted to assess the pond's dimensions, collect bathymetric data, and install temperature sensors at various locations and depths.

The heat balance model uses data from the pond and a nearby weather station to quantify temperature effects on the surface water system. By performing a heat balance of the water body, considering various factors, including solar radiation, wind speed, air temperature, and heat fluxes, the study evaluates the extractable thermal energy from the pond and assesses its suitability for low-temperature heating and cooling applications.

Finally, a design analysis of the pilot aquathermal system is presented, considering technical feasibility, integration with existing building energy systems, and potential scalability across the campus. The contribution also provides recommendations for implementing a more sophisticated data acquisition and monitoring system.

The findings provide practical insights for advancing sustainable energy solutions in dense urban environments and support the broader implementation of aquathermal technologies in the Netherlands.

How to cite: Fremouw, M., Koulidis, A., and Bloemendal, M.: Assessing and Designing a Pilot Aquathermal System on the TU Delft Campus, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19295, https://doi.org/10.5194/egusphere-egu26-19295, 2026.

Contourite sandstones exhibit high lateral continuity, moderate to high porosity (depending on diagenetic overprint), and are typically overlain by fine-grained marls, making them promising candidates for subsurface CO₂ storage. This study investigates contourite channel deposits of late Miocene age that outcrop in the Rifian Corridor (northern Morocco). A fine-grained, bioclastic–siliciclastic sandstone and a medium- to coarse-grained sand representing potential reservoir materials were selected for controlled CO₂–rock interaction experiments.

CO₂ exposure tests were conducted in a batch reactor at 8 MPa and 40 °C for 30 days. Textural and pore-space changes were assessed through comparative SEM imaging, and bulk-rock and brine chemical compositions were analysed before and after exposure. The first reservoir sample experienced only minor dissolution features and limited particle detachment. In contrast, the fine-grained reservoir candidate underwent pronounced physical disintegration during CO₂ exposure. Chemical alteration was modest in both lithologies, expressed mainly as slight increases in dissolved ion concentrations in the brines.

These results highlight contrasting mechanical responses of contourite channel facies to CO₂ exposure and underscore the importance of lithological variability when evaluating contourite systems for CO₂ storage applications.

This research was conducted within the ALGEMAR Project (Ref. PID2021-123825OB-I00), funded by the Plan Nacional of Spanish Ministry of Science and Innovation

How to cite: Berrezueta, E., Kovács, T., Ordóñez-Casado, B., LLave, E., Benjumea, B., Canteli, P., Mediato, J., Hernández-Molina, J., and de Weger, W.: CO2 storage potential of contourite channels – Laboratory studies on geochemical reactions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9664, https://doi.org/10.5194/egusphere-egu26-9664, 2026.

This study investigates mineralogical and geochemical alterations at the matrix scale in carbonate-rich sandstone exposed to supercritical CO₂ (SC-CO₂) and formation brine. Batch experiments were conducted under reservoir conditions (≈8 MPa, 333ºK) to simulate the early stages of CO₂ injection in a deep sedimentary formation of the Guadalquivir Basin (southern Spain).

Rock samples were analysed before and after exposure using scanning electron microscopy (SEM) with microanalysis, X-ray fluorescence (XRF), and X-ray diffraction (XRD). Complementarily, chemical analyses of the brine before and after the experiments were performed. The interaction with CO₂-rich brine caused a marked pH decrease, leading to carbonate dissolution and minor alteration of clay minerals. The Ca concentration in the brine increased by about 300%, confirms active carbonate dissolution driven by CO₂-induced acidification. These reactions, together with particle detachment and micro-scale pore modification, indicate dynamic fluid-rock interactions within the calcarenite matrix.

The results show up that the studied reservoir rocks maintain overall structural integrity under CO₂-rich conditions while undergoing measurable geochemical alteration. This experimental framework provides a reproducible approach to evaluate mineral reactivity and textural evolution in carbonate-rich sandstone reservoirs, offering relevant insights to the design and assessment of CO₂ sequestration projects in comparable geological settings.

This research was conducted within the UNDERGY Project (Ref. MIG-20211018), funded by the Programa Misiones CDTI 2021 of the Spanish Ministry of Science and Innovation and the Next Generation EU Fund.

How to cite: Ordóñez-Casado, B., Ledesma, S., Mediato, J., Kóvacs, T., Chinchilla, D., González-Menéndez, L., and Berrezueta, E.: Carbonate-rich Sandstone Reactivity to Supercritical CO₂ and Brine: A Case Study from the Guadalquivir Basin, Spain, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10232, https://doi.org/10.5194/egusphere-egu26-10232, 2026.

Underground coal gasification (UCG) offers a viable approach for extracting deep-seated coal deposits with minimal surface disruption. The thermomechanical behavior of adjacent rock formations, particularly shale, which typically acts as a ceiling or floor rock, has a significant impact on the success of UCG operations. This study examines the pore structure evolution of shale samples at increased temperatures from room temperature to 800 °C, approximating the thermal range experienced during UCG procedures. The primary goal is to understand how high-temperature exposure changes the porosity and microstructure of shale, altering gas movement, confinement, and overall system stability.

Shale samples were collected from Jharia Basin, India, and were heated in a muffle furnace at gradually increasing temperatures. The pore properties were assessed by Low-Pressure Gas Adsorption (LPGA), Helium Pycnometry, and Scanning Electron Microscopy (SEM). SEM imaging showed considerable microcrack formation and intergranular pore growth at temperatures above 300 °C. LPGA data showed a shift from microporous to meso- and macroporous materials as temperature increased, implying gradual pore coalescence. The Helium Pycnometer results verified a temperature-dependent increase in apparent porosity, which corresponded well to the observed physical degradation. The findings show a non-linear rise in total porosity and considerable microstructural disintegration of shale at high temperatures, which can improve gas flow paths but may expose the confining layers' stability. These thermal changes are critical to UCG operations because they affect both gas recovery efficiency and subsurface safety. The work sheds light on the thermal behavior of shale under UCG-relevant conditions, emphasizing the importance of complete thermomechanical studies in site selection and operational planning for UCG projects.

Keywords: Underground Coal Gasification, LPGA, Permeability, temperature, Porosity.

How to cite: Sahoo, S. S.: Temperature-Induced Pore Structure Evolution in Shale: Implications for Underground Coal Gasification Applications , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19786, https://doi.org/10.5194/egusphere-egu26-19786, 2026.

Groundwater-induced subsurface collapse presents a critical geotechnical hazard in karst terrains, which poses heavy risks to global public safety and infrastructure. Despite the substantial economic impact, predicting these failures remains challenging due to sparse subsurface monitoring and the difficulty of integrating indirect, multi-modal satellite data into traditional models. To address the challenge of low observability, we present a physics-informed neural network (PINN)-based digital twin for simulating coupled hydro-mechanical processes. The framework integrates NASA GPM (IMERG) precipitation data and Sentinel-1 InSAR surface deformation measurements to constrain subsurface dynamics. Implemented in the West-Central Florida Karst Belt, the model represents a three-dimensional domain of unconsolidated overburden overlying a weathered limestone aquifer. Subsurface dynamics are governed by transient Darcy flow and an effective stress relationship, while progressive material weakening is captured through a continuous damage variable, d, which evolves via stress redistribution and pore-pressure diffusion. Through minimizing the residuals of these governing equations, the PINN identifies the start of collapse, defined as the point where localized damage exceeds a critical threshold. Our results indicate that the digital twin produces physically consistent fields with 25–30% lower error in pore pressure and damage predictions compared to simulations that are uncoupled. Predicted collapse initiation times, Tc, remained within 18–23% of benchmark solutions, capturing time-accelerated failure during intense recharge events. Sensitivity analysis reveals that hydraulic conductivity, K, accounts for over 63% of damage variance, highlighting the model's physical interpretability. This framework provides a scalable approach for real-time hazard assessment in data-poor karst regions globally.

How to cite: Korada, S. and Liu, W.: PINN-Based Digital Twins for Modeling Groundwater-Induced Subsurface Collapse under Low-Observability Hydro-Mechanical Conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16204, https://doi.org/10.5194/egusphere-egu26-16204, 2026.

The growing demand for Critical and Strategic Raw Materials (CRMs, SRMs) and the limited availability of primary resources in Europe have renewed regulatory and scientific interest in mine waste and tailings as secondary raw material sources (European Critical Raw Materials Act 2023; Hool et al. 2024). Accordingly, efficient and environmentally sustainable extraction technologies are necessary to minimize both environmental impact and processing costs (Whitworth et al. 2022). Among emerging solutions to conventional acidic leaching, glycine has been attracting attention as a non-toxic and biodegradable amino acid capable of forming stable complexes with calcophile elements under alkaline conditions and low temperatures, enabling low-cost, possible industrial applications for recovering precious and critical metals from mine waste and tailings (O’Connor et al. 2018; Barragán-Mantilla et al. 2024; Eksteen et al. 2018). This study investigated the application of glycine leaching as a green chemical approach for the recovery of copper from fine-grained historical tailings samples from the Fenice–Capanne mine, Tuscany, Italy.

Historical tailings samples were preliminarily characterised in terms of granulometry, geochemical and mineralogical composition using multiple methodologies, such as ICP-MS, HH-XRF, SEM-EDS and SEM-MLA for the definition of metal grades and the identification of metal-bearing minerals. Batch leaching tests were conducted using a glycine solution under controlled conditions, including alkaline pH, a constant liquid-to-solid ratio, and progressively increasing leaching times. The performance of glycine as a lixiviant was evaluated in terms of metal extraction efficiency and selectivity using HH-XRF on solid residues and ICP-OES on leaching liquors. Particular focus was addressed on Cu and associated Zn extraction. As a term of comparison, the same samples were leached using sulphuric acid leaching.

Preliminary results indicated that glycine leaching enabled the selective extraction of Cu and minor Zn while limiting the dissolution of Fe, and competitive recovery rates when compared to traditional sulphuric acid leaching. It highlighted its potential as an environmentally friendly leaching agent. The outcomes of this study could contribute to the assessment of sustainable options for the recovery of CRMs and SRMs from mine tailings within a sustainable and circular economy approach.

How to cite: Baldassarre, G., Zasa Courtial, V., Bellopede, R., and Marini, P.: Selective recovery of copper from mine tailings using a green leaching agent, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19216, https://doi.org/10.5194/egusphere-egu26-19216, 2026.

CO₂ storage in basalt is considered one of the safest geological sequestration methods, as injected CO₂ reacts with basaltic minerals to form stable carbonates. Flood basalt provinces offer additional advantages, particularly their very low matrix permeability and their three-tier structure, where a vesicular or fractured zone lies between two low permeable massive units. The vesicular zone is often regarded as a suitable storage interval because of its high lateral permeability. These basalt flows are often intersected by dykes, which are commonly dominated with cooling joints. Similar dyke swarms are a characteristic feature of many basaltic terrains around the world, including the Columbia River Basalt Group, the Deccan Traps, and the Spanish Peaks. In India, such fractured dykes frequently serve as pathways for groundwater recharge during the monsoon. As the Deccan basalts in India, are now being examined as a potential large-scale CO₂ storage reservoir, the presence of tens of thousands of dykes presents a serious challenge. These dykes may act as conduits for groundwater contamination or possible leakage routes for injected CO₂. In this study, we numerically examined the effect of a fractured dyke with high vertical permeability intersecting a storage layer at 1.5 km depth using a multiphase flow model. Supercritical CO₂ was injected into a 50 m thick storage interval fully saturated with brine. The permeability of both the dyke and the host layer was derived from discrete fracture network modelling of representative field exposures. The results show that the dyke allows upward migration of CO₂, indicating a clear leakage risk that questions the practical feasibility of large-scale storage in such settings. Because sealing individual dykes is not realistic, and many serve as natural groundwater pathways, the hydrodynamics of dyke systems must be carefully evaluated before any CO₂ injection activity. The results also indicate that sills may offer a more secure storage option.

How to cite: Das, D., Pavan, T., and Vedanti, N.: CO₂ Migration and Leakage Risk in Dyke-Dominated Basaltic Reservoirs: A Multiphase Flow Modelling Study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1226, https://doi.org/10.5194/egusphere-egu26-1226, 2026.

South Korea depends largely on imports to secure its critical minerals. In the case of lithium, 66% of the demand is imported from China and 31% from Chile, while the price of Lithium continues to rise with the growth of the battery market. By the end of 2025, copper prices are expected to continue rising due to the supply crisis, intensifying the competition for securing resources. To address this international resource-securing crisis, this research focuses on the possibility of recovering metals from waste resources generated by domestic renewable energy facilities.

South Korea operates four Future Waste Resources Base Collection Centers to collect waste batteries from electric vehicles(EV), waste solar panel and wind turbine, conducting performance assessment and resale. However, a detailed analysis of whether waste batteries and panels are reused or recycled is not traceable, thereby limiting the accurate measurement of resource-circulation efficiency.

Although the recovery rates of waste batteries is high(about 14,000 units in 2024), but it is not traceable whether they are reused for energy storage systems(ESS) or recycled for resource recovery. To address this limitation, since 2025, the introduction of the Battery Lifecycle Management System has enabled full lifecycle tracing of EV batteries, whereas batteries from other sources remain outside the tracking system.

Since 2023, the implementation of the Extended Producer Responsibility system for waste solar panels has aimed to enhance resource-circulation efficiency. But the actual quantities recycled, reused, or simply discarded remain unclear, even if the projected amount of waste solar panels in 2025 is 14,596 tons according to the Korea Environment Institute.

While attention is often given to the recycling of wind turbine blades, wind power facilities also possess significant potential for metal resource recovery, as they contain approximately 4.3 tons of copper per MW in onshore installations and 9.6 tons per MW in offshore installations. In particular, a recovery potential of approximately 1,870 tons of copper is estimated from about 483MW of wind power facilities that are expected to reach the end of their life cycle in the early 2030s. Nevertheless, the recycling status of components other than nacelles and blades, such as towers and cables, remains entirely unverified.

Therefore, the introduction of a full-lifecycle tracing system for renewable energy waste resources is proposed. Similar to the Battery Lifecycle Management System, identification numbers are assigned to solar panels and wind power facilities so that the entire process from production to disposal and recycling can be traced, thereby visualizing the domestic circulation path of metal resources and providing a basis for enhancing the actual recycling rate.

How to cite: Kim, J. and Park, H.-D.: Lifecycle Traceability System for Metal Recovery from Renewable Energy Waste in South Korea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6063, https://doi.org/10.5194/egusphere-egu26-6063, 2026.

The global energy transition is accelerating due to the climate crisis, with nations aiming for net-zero emissions as outlined in the “UAE Consensus” from the 28th United Nations Climate Change Conference (COP28). Sub-Saharan Africa must balance climate resilience and economic growth. Geothermal energy, a low-carbon, under-explored alternative to fossil fuels, can help Nigeria meet expanding energy needs. The study which aims to aims to develop an integrated, multi-scale approach for assessing geothermal resource potential employed a multi-criteria decision-making framework combining Fuzzy AHP and TOPSIS to assess geothermal potential across Nigeria’s 37 states. Fuzzy AHP provided weighted criteria, while TOPSIS calculated performance scores based on each state’s proximity to the ideal solution. Initial findings suggest that most of the highest-ranked states for geothermal potential align within regions influenced by the most recent magmatic activities in Nigeria, which occurred during the Tertiary period The analysis showed a wide spread of results, reflecting significant regional variability in geothermal conditions. Nasarawa, Bauchi, and Benue ranked highest, indicating strong geothermal suitability. Lagos, Gombe, and Ogun ranked lowest, while states such as Rivers, Katsina, and Niger showed moderate potential. Meanwhile, we will undertake targeted fieldwork in high-prospect states to map structural features at outcrop scale and conduct geochemical analysis.

How to cite: Yohanna, O.: Integrated Approach for Low-Enthalpy Geothermal Resource Appraisal and Assessment in Nigeria: Implications for Net-Zero Target , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20884, https://doi.org/10.5194/egusphere-egu26-20884, 2026.

Abstract

Fracture characterization and modeling are essential for hydrocarbon exploration and enhanced production. To model the fracture network in the Asmari reservoir of the Rag-e-Sefid Oilfield (SW Iran), this research characterizes fracture intensity using well, fracture driver, and fracture controller data. First, these data are analyzed to estimate fracture intensity. Then, fracture intensity is modeled using geostatistical methods. The geostatistical outputs are compared and calibrated based on the structural setting of the study area and the fracture indicator. Finally, selected fracture intensity data are integrated into a single model using an artificial neural network, resulting in a comprehensive fracture intensity model for the Asmari reservoir of the Rag-e-Sefid Oilfield. The results show that fracture intensity increases near the Rag-e-Sefid and Nourooz-Hendijan-Izeh Faults and in the fold forelimb and crest. The highest fracture intensity in the Asmari reservoir is observed at the intersection of structures with the N-S Arabian trend and the NW-SE Zagros trend, where the fold axis has rotated. Generally, the northwestern part of the Rag-e-Sefid anticline has higher fracture intensity than the southeastern part. The high fracture intensity in the northwest part of the Rag-e-Sefid Oilfield is related to inversion tectonics, multi-stage reactivation along pre-existing basement structures, and an older deformation history in this area compared to its southeastern part. The Asmari reservoir in the NW part of the Rag-e-Sefid anticline contains a greater share of oil and gas in its hydrocarbon traps than the SE part. Moreover, the results of this study indicate that the simultaneous use of different data and the integration of geostatistical and artificial neural network methods can effectively predict fracture distribution in hydrocarbon reservoirs and be used as a suitable technique for fracture modeling in natural oil and gas fields. This research suggests that artificial intelligence and quantum computing techniques provide efficient solutions for characterizing and modeling the entire scale of geological fractures in hydrocarbon reservoirs.

Keywords: Fracture modeling, Geostatistical and neural network methods, Asmari reservoir, Rag-e-Sefid Oilfield, SW Iran

How to cite: Tajmir Riahi, Z., Faghih, A., Soleimany, B., Sarkarinejad, K., and Payrovian, G. R.: Fracture modeling of the hydrocarbon reservoir using geostatistical and neural network methods in the SW Iran Oilfield , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2105, https://doi.org/10.5194/egusphere-egu26-2105, 2026.