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The pursuit of sustainable power solutions has become imperative in the face of global environmental challenges and the growing energy demand. This abstract explores the advancements in renewable energy and energy storage technologies, aiming to create a comprehensive understanding of their role in achieving a sustainable future. Renewable energy sources, such as solar, wind, hydro, geothermal, and biomass, have gained significant traction due to their abundance, low environmental impact, and decreasing costs. Breakthroughs in photovoltaic technology have increased solar energy efficiency, making it a more viable option for widespread adoption. Similarly, innovations in wind turbine design and materials have bolstered the efficiency and reliability of wind power generation. However, the intermittent nature of renewable energy sources poses a challenge to their integration into the grid, highlighting the critical importance of energy storage systems. Advancements in energy storage technologies, including lithium-ion batteries, flow batteries, hydrogen storage, and thermal storage, have been instrumental in mitigating the variability of renewable sources. These developments have enhanced the stability and flexibility of energy systems, enabling a smoother integration of renewables into existing grids. Predictive analytics and control systems are pivotal in maximizing renewable resources' efficiency and storage units' efficiency while ensuring grid stability and reliability.

Accurate and efficient predictions of three-dimensional subsurface stress changes are required for the assessment of geothermal operations with respect to fault stability and the potential risk for induced seismicity. This work extends the model capabilities of Mechanical Analysis of Complex Reservoirs for Induced Seismicity (MACRIS) to account for high-resolution thermo-elastic stress evaluations in structurally complex (i.e. faulted) and matrix permeability dominated geothermal systems. By adopting a mesh-free approach suitable to industry standard flow simulation models, MACRIS is capable of preserving the complex 3D hydraulic development of the injected cold-water volume and the 3D geometrical complexities of the reservoir model. The workflow has been applied to three-dimensional models with clastic reservoir characteristics representative for low enthalpy geothermal exploitation in the Netherlands. The models are marked by a single fault, subject to no and normal offset. Comparison of simulated stress evolutions in MACRIS with alternative analytical solutions highlight the effects of stress arching involved in the poro- and thermo-elastic stress developments on complex faults intersected by or in direct contact with the cold-water volume. Results are in agreement with previous studies and show the effect of thermal stressing to be dominant, arching of stresses to occur at the rim of the cold-water volume, and in cooling reservoirs, the intersection area of the cold-water volume in direct contact with the fault plane to be the main driver for fault reactivation and subsequent seismic potential. Moreover, results show the effects of stress arching (i) to be enhanced in the case of reservoir throw and flow compartmentalization, and (ii) to be reduced by a relative increase in conductive heat transfer between the reservoir and surrounding formations.

Energy transitions are knowledge-intensive processes where a multitude of actors are trying to cope with inevitable knowledge gaps, surprises, and uncertainties. In this context, we focus on two techno-physical phenomena that are gaining practical relevance with the expansion of wind and geothermal energy extraction, and are surrounded by significant unknowns: wake effects and temperature plumes. Both phenomena can potentially affect the efficiency of energy production, but the extent of their impact is not yet known. Based on 28 semi-structured interviews with experts in the fields of wind and geothermal energy, we explore how different central actors perceive and interpret non-knowledge of wake effects and temperature plumes, and how they deal with it. We show that there are strategies for either using non-knowledge as a basis for action or simply ignoring it and sweeping knowledge gaps under the rug. Both strategies serve the function of protecting agency and keeping things going.

Pyrite is a ubiquitous sulfide mineral found in diverse geological settings and holds great significance in the formation of Au deposits as well as the safe utilization of groundwater due to its remarkable ability to incorporate substantial amounts of As. However, despite its importance, there remains a dearth of fundamental data on the partitioning of As between pyrite and fluid, which is key for accurately modeling the As distribution in these environments. Here, we present new insights into the partitioning behavior of As between pyrite and fluid at conditions that mimic natural fluid systems. Pyrite was synthesized by replacement of natural siderite in hydrothermal experiments at 200 °C and pH 5 applying a wide range of fluid As concentrations, spanning from 0.001 to 100 µg/g. The As distribution and concentration in synthetic pyrite was analyzed by quantitative LA-ICP-MS mapping providing a high spatial resolution and sensitivity at 2–3 µm image pixel size at a detection limit of ∼1 µg/g at the single pixel scale. Pyrite-fluid partitioning coefficients (DAs(py/fluid)) between synthetic pyrite and experimental fluid agree with previously published data for high fluid As concentrations of 1 µg/g to 100 µg/g (DAs < 2000). However, at low As concentrations in the experimental fluid (<1 µg/g), a steep increase in the DAs(py/fluid) values of up to ∼30,000 was detected, demonstrating even stronger As partitioning into pyrite. This is confirmed by the analyses of natural pyrite that precipitated from As-poor fluids (0.3–0.4 ng/g) within a deep anoxic aquifer in SE Sweden. The discovery holds significant implications for the mobility and scavenging of As, which in turn is important for understanding the formation and fingerprinting of mineral deposits as well as for the secure utilization of groundwater resources.

Pyrite is a ubiquitous sulfide mineral found in diverse geological settings and holds great significance in the formation of Au deposits as well as the safe utilization of groundwater due to its remarkable ability to incorporate substantial amounts of As. However, despite its importance, there remains a dearth of fundamental data on the partitioning of As between pyrite and fluid, which is key for accurately modeling the As distribution in these environments. Here, we present new insights into the partitioning behavior of As between pyrite and fluid at conditions that mimic natural fluid systems. Pyrite was synthesized by replacement of natural siderite in hydrothermal experiments at 200 °C and pH 5 applying a wide range of fluid As concentrations, spanning from 0.001 to 100 µg/g. The As distribution and concentration in synthetic pyrite was analyzed by quantitative LA-ICP-MS mapping providing a high spatial resolution and sensitivity at 2–3 µm image pixel size at a detection limit of ∼1 µg/g at the single pixel scale. Pyrite-fluid partitioning coefficients (DAs(py/fluid)) between synthetic pyrite and experimental fluid agree with previously published data for high fluid As concentrations of 1 µg/g to 100 µg/g (DAs < 2000). However, at low As concentrations in the experimental fluid (<1 µg/g), a steep increase in the DAs(py/fluid) values of up to ∼30,000 was detected, demonstrating even stronger As partitioning into pyrite. This is confirmed by the analyses of natural pyrite that precipitated from As-poor fluids (0.3–0.4 ng/g) within a deep anoxic aquifer in SE Sweden. The discovery holds significant implications for the mobility and scavenging of As, which in turn is important for understanding the formation and fingerprinting of mineral deposits as well as for the secure utilization of groundwater resources.

Pyrite is a ubiquitous sulfide mineral found in diverse geological settings and holds great significance in the formation of Au deposits as well as the safe utilization of groundwater due to its remarkable ability to incorporate substantial amounts of As. However, despite its importance, there remains a dearth of fundamental data on the partitioning of As between pyrite and fluid, which is key for accurately modeling the As distribution in these environments. Here, we present new insights into the partitioning behavior of As between pyrite and fluid at conditions that mimic natural fluid systems. Pyrite was synthesized by replacement of natural siderite in hydrothermal experiments at 200 °C and pH 5 applying a wide range of fluid As concentrations, spanning from 0.001 to 100 µg/g. The As distribution and concentration in synthetic pyrite was analyzed by quantitative LA-ICP-MS mapping providing a high spatial resolution and sensitivity at 2–3 µm image pixel size at a detection limit of ∼1 µg/g at the single pixel scale. Pyrite-fluid partitioning coefficients (DAs(py/fluid)) between synthetic pyrite and experimental fluid agree with previously published data for high fluid As concentrations of 1 µg/g to 100 µg/g (DAs < 2000). However, at low As concentrations in the experimental fluid (<1 µg/g), a steep increase in the DAs(py/fluid) values of up to ∼30,000 was detected, demonstrating even stronger As partitioning into pyrite. This is confirmed by the analyses of natural pyrite that precipitated from As-poor fluids (0.3–0.4 ng/g) within a deep anoxic aquifer in SE Sweden. The discovery holds significant implications for the mobility and scavenging of As, which in turn is important for understanding the formation and fingerprinting of mineral deposits as well as for the secure utilization of groundwater resources.

To effectively reduce building energy consumption, a novel full fresh air system with a heat source tower (HST) and a borehole heat exchanger (BHE) was proposed for space cooling and dehumidification in this paper. The cooling system only adopts geothermal energy to produce dry and cold fresh air for space cooling and dehumidification through the BHE and HST, which has the advantage of non-condensate water compared to BHE systems integrated with a fan coil or chilled beam. Based on the established mathematical model of the cooling system, this paper analyzed the system characteristics, feasibility, operation strategy, energy performance, and cost-effectiveness of the proposed model in detail. The results show that the mathematical model has less than 10% error in estimating the system performance compared to the practical HST-BHE experimental set up. Under the specific boundary conditions, the cooling and dehumidification capacity of this system increases with the decrease in the air temperature, air moisture content, and inlet water temperature of the HST. The optimal cooling capacity and the system COP can be achieved when the air-water flow ratio is at 4:3. A case study was conducted in a residential building in Shenyang with an area of about 1800 m2. It was found that this system can fully meet the cooling and dehumidification demand in such a residential building. The operation strategy of the cooling system can be optimized by adjusting the air-water flow ratio from 4:3 to 3:2 during the early cooling season (7 June-1 July) and end cooling season (3 August-1 September). As a result, the average COP of the cooling system during the whole cooling season can be improved from 6.1 to 8.7. Compared with the air source heat pump (ASHP) and the ground source heat pump (GSHP) for space cooling, the proposed cooling system can achieve an energy saving rate of 123% and 26%, respectively. Considering that the BHE of the GSHP can be part of the proposed HST-BHE cooling sys

Pyrite is a ubiquitous sulfide mineral found in diverse geological settings and holds great significance in the formation of Au deposits as well as the safe utilization of groundwater due to its remarkable ability to incorporate substantial amounts of As. However, despite its importance, there remains a dearth of fundamental data on the partitioning of As between pyrite and fluid, which is key for accurately modeling the As distribution in these environments. Here, we present new insights into the partitioning behavior of As between pyrite and fluid at conditions that mimic natural fluid systems. Pyrite was synthesized by replacement of natural siderite in hydrothermal experiments at 200 °C and pH 5 applying a wide range of fluid As concentrations, spanning from 0.001 to 100 µg/g. The As distribution and concentration in synthetic pyrite was analyzed by quantitative LA-ICP-MS mapping providing a high spatial resolution and sensitivity at 2–3 µm image pixel size at a detection limit of ∼1 µg/g at the single pixel scale. Pyrite-fluid partitioning coefficients (DAs(py/fluid)) between synthetic pyrite and experimental fluid agree with previously published data for high fluid As concentrations of 1 µg/g to 100 µg/g (DAs < 2000). However, at low As concentrations in the experimental fluid (<1 µg/g), a steep increase in the DAs(py/fluid) values of up to ∼30,000 was detected, demonstrating even stronger As partitioning into pyrite. This is confirmed by the analyses of natural pyrite that precipitated from As-poor fluids (0.3–0.4 ng/g) within a deep anoxic aquifer in SE Sweden. The discovery holds significant implications for the mobility and scavenging of As, which in turn is important for understanding the formation and fingerprinting of mineral deposits as well as for the secure utilization of groundwater resources.

To effectively reduce building energy consumption, a novel full fresh air system with a heat source tower (HST) and a borehole heat exchanger (BHE) was proposed for space cooling and dehumidification in this paper. The cooling system only adopts geothermal energy to produce dry and cold fresh air for space cooling and dehumidification through the BHE and HST, which has the advantage of non-condensate water compared to BHE systems integrated with a fan coil or chilled beam. Based on the established mathematical model of the cooling system, this paper analyzed the system characteristics, feasibility, operation strategy, energy performance, and cost-effectiveness of the proposed model in detail. The results show that the mathematical model has less than 10% error in estimating the system performance compared to the practical HST-BHE experimental set up. Under the specific boundary conditions, the cooling and dehumidification capacity of this system increases with the decrease in the air temperature, air moisture content, and inlet water temperature of the HST. The optimal cooling capacity and the system COP can be achieved when the air-water flow ratio is at 4:3. A case study was conducted in a residential building in Shenyang with an area of about 1800 m2. It was found that this system can fully meet the cooling and dehumidification demand in such a residential building. The operation strategy of the cooling system can be optimized by adjusting the air-water flow ratio from 4:3 to 3:2 during the early cooling season (7 June-1 July) and end cooling season (3 August-1 September). As a result, the average COP of the cooling system during the whole cooling season can be improved from 6.1 to 8.7. Compared with the air source heat pump (ASHP) and the ground source heat pump (GSHP) for space cooling, the proposed cooling system can achieve an energy saving rate of 123% and 26%, respectively. Considering that the BHE of the GSHP can be part of the proposed HST-BHE cooling sys

Pyrite is a ubiquitous sulfide mineral found in diverse geological settings and holds great significance in the formation of Au deposits as well as the safe utilization of groundwater due to its remarkable ability to incorporate substantial amounts of As. However, despite its importance, there remains a dearth of fundamental data on the partitioning of As between pyrite and fluid, which is key for accurately modeling the As distribution in these environments. Here, we present new insights into the partitioning behavior of As between pyrite and fluid at conditions that mimic natural fluid systems. Pyrite was synthesized by replacement of natural siderite in hydrothermal experiments at 200 °C and pH 5 applying a wide range of fluid As concentrations, spanning from 0.001 to 100 µg/g. The As distribution and concentration in synthetic pyrite was analyzed by quantitative LA-ICP-MS mapping providing a high spatial resolution and sensitivity at 2–3 µm image pixel size at a detection limit of ∼1 µg/g at the single pixel scale. Pyrite-fluid partitioning coefficients (DAs(py/fluid)) between synthetic pyrite and experimental fluid agree with previously published data for high fluid As concentrations of 1 µg/g to 100 µg/g (DAs < 2000). However, at low As concentrations in the experimental fluid (<1 µg/g), a steep increase in the DAs(py/fluid) values of up to ∼30,000 was detected, demonstrating even stronger As partitioning into pyrite. This is confirmed by the analyses of natural pyrite that precipitated from As-poor fluids (0.3–0.4 ng/g) within a deep anoxic aquifer in SE Sweden. The discovery holds significant implications for the mobility and scavenging of As, which in turn is important for understanding the formation and fingerprinting of mineral deposits as well as for the secure utilization of groundwater resources.

In this study, we present an efficient and flexible adjoint-based framework for history matching and forecasting geothermal energy extraction at a large scale. In this framework, we applied the Principal Component Analysis to reduce the parameter space for representing the complex geological model. The adjoint method is implemented for gradient calculation to speed up the history-matching iteration process. Operator-based linearization (OBL) used in this framework makes the calculation of the physical state and its derivatives very efficient and facilitates the matrix assembly in the adjoint method. This study primarily focuses on history matching based on combined observation of well production and in-situ electromagnetic measurements to predict the temperature front. However, different types of misfit terms can be added to the objective function based on practical considerations. For example, our history-matching case studies include model misfit terms applied for regularization purposes. The measurement data is extracted from the true model, and realistic measurement errors are considered. Also, in this work, we propose an optimal weighting strategy for the terms of the objective function to balance their sensitivity with respect to the model control variables. The high efficiency of the framework is demonstrated for the geothermal doublet model implemented at the heterogeneous reservoir with multiple realizations. The framework allows for generating posterior Randomized Maximum Likelihood (RML) estimates of the entire ensemble of the realizations with a reasonable computational cost. Results show that the framework can achieve reliable history-matching results based on the doublets production data and the reservoir electromagnetic measurement., Reservoir Engineering

Geological Carbon Storage (GCS) is considered a promising technology to lower atmospheric emissions of CO2. Guaranteeing the sealing capacity of caprocks in this case becomes paramount as CO2 storage scales up to the gigaton scale. Many laboratory experiments have been performed with samples of intact rock, showing that low-permeability and high-entry pressure caprocks have excellent sealing capacities to contain CO2 deep underground. However, discontinuities, such as bedding planes, fractures, and faults, affect the rock properties at the field scale, being at the same time challenging to monitor in industrial-scale applications. The main objective of the thesis is to develop a methodology to characterize potential sites for low-carbon geo-energy applications at multiple scales in space and time, taking into account coupled processes. To achieve this objective, it is necessary to understand the complexity of the problem at multiple scales, starting from large-scale investigations, passing through in-situ underground rock laboratories, to laboratory investigations. This is why this thesis approaches characterizations that span a wide range of spatiotemporal scales from the order of millimeters and nanoseconds to the order of kilometers and decades. To achieve this general objective, the first part of the thesis explores four analytical solutions of pore pressure diffusion with periodic sources under relevant model geometries and boundary conditions to enable real-time interpretation of in-situ data. We compare the results with numerical solutions, assuming the same conditions as the analytical cases and incorporating reservoir deformation due to pressure waves. Encompassing three different cases to span a wide array of scenarios, we evaluate the attenuation of the signal at varying distances from the source. Numerical and analytical solutions fit when identical assumptions are upheld. Furthermore, the influence of effective mean stress variations yields errors of le

En el trabajo de grado expuesto a continuación se presenta un modelo de negocio para una empresa dedicada a la generación de electricidad a partir de la energía geotérmica en Colombia, por medio de cinco capítulos principales. El primero de estos consistió en realizar un diagnóstico del sector minero energético y del subsector energía, así como en evaluar los factores políticos, económicos, sociales, tecnológicos, legales y ambientales; adicionalmente, se evaluaron las cinco fuerzas de Porter y se desarrolló una matriz DOFA para identificar las fortalezas y debilidades del negocio propuesto, y las oportunidades y amenazas del entorno, a partir de las cuales se elaboraron estrategias de crecimiento, adaptación, defensa y supervivencia para la compañía. El segundo capítulo comprende el estudio de mercado, en donde se estableció la justificación y antecedentes del proyecto; y las estrategias de distribución, precio, promoción, comunicación, servicio y aprovisionamiento del producto. Por otra parte, el desarrollo del tercer capítulo, correspondiente al estudio de ingeniería, abarca la presentación y justificación de la organización, la descripción y ficha técnica del servicio, el diagrama del proceso administrativo y flujo de proceso de las operaciones, y la distribución en planta.

To effectively reduce building energy consumption, a novel full fresh air system with a heat source tower (HST) and a borehole heat exchanger (BHE) was proposed for space cooling and dehumidification in this paper. The cooling system only adopts geothermal energy to produce dry and cold fresh air for space cooling and dehumidification through the BHE and HST, which has the advantage of non-condensate water compared to BHE systems integrated with a fan coil or chilled beam. Based on the established mathematical model of the cooling system, this paper analyzed the system characteristics, feasibility, operation strategy, energy performance, and cost-effectiveness of the proposed model in detail. The results show that the mathematical model has less than 10% error in estimating the system performance compared to the practical HST-BHE experimental set up. Under the specific boundary conditions, the cooling and dehumidification capacity of this system increases with the decrease in the air temperature, air moisture content, and inlet water temperature of the HST. The optimal cooling capacity and the system COP can be achieved when the air-water flow ratio is at 4:3. A case study was conducted in a residential building in Shenyang with an area of about 1800 m2. It was found that this system can fully meet the cooling and dehumidification demand in such a residential building. The operation strategy of the cooling system can be optimized by adjusting the air-water flow ratio from 4:3 to 3:2 during the early cooling season (7 June-1 July) and end cooling season (3 August-1 September). As a result, the average COP of the cooling system during the whole cooling season can be improved from 6.1 to 8.7. Compared with the air source heat pump (ASHP) and the ground source heat pump (GSHP) for space cooling, the proposed cooling system can achieve an energy saving rate of 123% and 26%, respectively. Considering that the BHE of the GSHP can be part of the proposed HST-BHE cooling sys

The pursuit of sustainable power solutions has become imperative in the face of global environmental challenges and the growing energy demand. This abstract explores the advancements in renewable energy and energy storage technologies, aiming to create a comprehensive understanding of their role in achieving a sustainable future. Renewable energy sources, such as solar, wind, hydro, geothermal, and biomass, have gained significant traction due to their abundance, low environmental impact, and decreasing costs. Breakthroughs in photovoltaic technology have increased solar energy efficiency, making it a more viable option for widespread adoption. Similarly, innovations in wind turbine design and materials have bolstered the efficiency and reliability of wind power generation. However, the intermittent nature of renewable energy sources poses a challenge to their integration into the grid, highlighting the critical importance of energy storage systems. Advancements in energy storage technologies, including lithium-ion batteries, flow batteries, hydrogen storage, and thermal storage, have been instrumental in mitigating the variability of renewable sources. These developments have enhanced the stability and flexibility of energy systems, enabling a smoother integration of renewables into existing grids. Predictive analytics and control systems are pivotal in maximizing renewable resources' efficiency and storage units' efficiency while ensuring grid stability and reliability.

Reducing energy costs in Europe is more challenging than before due to extreme price increases. The use of local renewable energy sources is one way to contribute to this effort. In the case of spa resorts, the use of heat from hot springs for therapeutic baths is an option. It is necessary to cool down this thermal mineral water to a temperature acceptable to the human body. However, due to the high mineral content of this water, heavy fouling can be a problem for conventional heat exchangers. The purpose of this study is to identify the suitable cooling technology in terms of required cooling capacity and waste heat recovery capability. The cooling technology was selected on the basis of a literature search. A pilot cooling unit consisting of vacuum cooler and plate heat exchanger was designed and tested in a real spa resort for six months. Both selected technologies have demonstrated the ability to cool thermal mineral water in long-term operation, as well as the possibility to utilize waste heat for domestic hot water heating. However, fouling problems occur in the plate heat exchanger. The vacuum cooler demonstrated greater operational robustness and resistance to encrustation.

Since 1968, studies have been conducted in the “Macizo Volcánico del Ruiz” that prove the great potential that exists in the region for the generation of electricity from geothermal energy. However, this development has not materialized yet. For this reason and with the aim of contributing to the development of geothermal energy in Colombia, the barriers that have been emerging in the implementation of the project were analyzed and to try to overcome some of these, a cascade development methodology was implemented based on a single producing well. The results showed that, with this new approach, the development of the field could be done in less time, with greater energy efficiency, adapting to the needs of the surrounding communities., Desde 1968, en el Macizo Volcánico del Ruiz se han realizado estudios que comprueban el gran potencial que existe en la región, para la generación de electricidad a partir de la energía geotérmica, sin embargo, este desarrollo no se ha materializado hasta la fecha. Por esta razón y con el ánimo de aportar en el desarrollo de la geotermia en Colombia, se analizaron las barreras que han venido surgiendo en la implementación del proyecto y para intentar superar algunas de estas se implementó una metodología de desarrollo en cascada a partir de un solo pozo productor. Los resultados mostraron que, con este nuevo enfoque, el aprovechamiento del campo se podría realizar en un menor tiempo, con una eficiencia energética mayor, adaptándose a las necesidades de las comunidades aledañas.

Factors such as fossilisation, diversification of energy resources, sustainable development, and energy security are attracting global attention for the development and expansion of renewable energy sources. Environmental issues arising from fossil fuel consumption are being addressed, but concerns remain about the renewability and availability of new energy sources. Mexico is one of the ten countries in the exploitation of geothermal energy, with a history of approximately five decades. This study examines Mexico's five major geothermal fields: Cerro Prieto, Los Azufres, Los Humeros, Las Tres Vírgenes, and Domo San Pedro. Currently, Mexico is working with international geothermal companies. However, there are more power plants and substantial cooperation to obtain this energy for industry and homes. This study is focused on the potential of geothermal exploitation in Mexico and its position worldwide after the introduction of geothermal energy in Mexico. Next, five geothermal fields are introduced in Mexico, and the potential and capacities of each are discussed. Finally, the future energy scenarios in Mexico are reviewed, with an emphasis on geothermal energy., Factores como la fosilización, la diversificación de los recursos energéticos, el desarrollo sostenible y la seguridad energética están atrayendo la atención mundial hacia el desarrollo y la expansión de las fuentes de energía renovables. Se están abordando los problemas medioambientales derivados del consumo de combustibles fósiles, pero sigue preocupando la renovabilidad y disponibilidad de nuevas fuentes de energía. México se encuentra entre los diez primeros países en explotación de energía geotérmica, con una historia de unas cinco décadas. El presente estudio examina los cinco principales campos geotérmicos de México: Cerro Prieto, Los Azufres, Los Humeros, Las Tres Vírgenes y Domo San Pedro. México trabaja actualmente con empresas geotérmicas internacionales; sin embargo, necesita más centrales y una mayor cooperación para hacer llegar esta energía a la industria y los hogares. El presente estudio analiza el potencial de la explotación geotérmica en México y su posición en el mundo tras la introducción de la energía geotérmica, después se discute el potencial y capacidades de cada uno de los campos geotérmicos. Finalmente, se revisan los escenarios energéticos futuros de México en general con énfasis en la energía geotérmica.

Reducing energy costs in Europe is more challenging than before due to extreme price increases. The use of local renewable energy sources is one way to contribute to this effort. In the case of spa resorts, the use of heat from hot springs for therapeutic baths is an option. It is necessary to cool down this thermal mineral water to a temperature acceptable to the human body. However, due to the high mineral content of this water, heavy fouling can be a problem for conventional heat exchangers. The purpose of this study is to identify the suitable cooling technology in terms of required cooling capacity and waste heat recovery capability. The cooling technology was selected on the basis of a literature search. A pilot cooling unit consisting of vacuum cooler and plate heat exchanger was designed and tested in a real spa resort for six months. Both selected technologies have demonstrated the ability to cool thermal mineral water in long-term operation, as well as the possibility to utilize waste heat for domestic hot water heating. However, fouling problems occur in the plate heat exchanger. The vacuum cooler demonstrated greater operational robustness and resistance to encrustation.

Reducing energy costs in Europe is more challenging than before due to extreme price increases. The use of local renewable energy sources is one way to contribute to this effort. In the case of spa resorts, the use of heat from hot springs for therapeutic baths is an option. It is necessary to cool down this thermal mineral water to a temperature acceptable to the human body. However, due to the high mineral content of this water, heavy fouling can be a problem for conventional heat exchangers. The purpose of this study is to identify the suitable cooling technology in terms of required cooling capacity and waste heat recovery capability. The cooling technology was selected on the basis of a literature search. A pilot cooling unit consisting of vacuum cooler and plate heat exchanger was designed and tested in a real spa resort for six months. Both selected technologies have demonstrated the ability to cool thermal mineral water in long-term operation, as well as the possibility to utilize waste heat for domestic hot water heating. However, fouling problems occur in the plate heat exchanger. The vacuum cooler demonstrated greater operational robustness and resistance to encrustation.

Long-term energy storage is expected to play a vital role in the deep decarbonization of building energy sectors, while enhancing the flexibility of buildings to withstand future climate variations. However, it is challenging to design distributed multi-energy systems (DMES) while taking into account the uncertainties introduced by climate change, since stochastic optimization of such systems is difficult. The present study introduces a stochastic optimization model to address this bottleneck, taking into account DMES including aquifer thermal energy storage (ATES) as the long-term thermal storage. For the first time, a novel optimization algorithm links ATES with the DMES optimization model with the support of a simplified geotechnical model. Subsequently, a case study was conducted, focusing on a residential district in Chicago where the impact of future climate condition, energy demand, and solar and wind energy potentials were evaluated using Weather Research and Forecasting (WRF) data (up to 2080) and the EnergyPlus model. The study revealed that ATES is an attractive way to improve the renewable energy penetration level and minimize the dependence on fossil fuels with reasonable support from the grid to assist the fluctuations in both demand and generation. Furthermore, ATES notably reduces fuel consumption and dependence while greatly enhancing the flexibility of the energy system to withstand fluctuations in demand and renewable energy generation brought by future climate variations. These qualities will make ATES an important part of distributed energy systems, even though it is not currently the lowest cost alternative due to lack of technology maturity. The design platform introduced in the present study can be used to design DMES enhancing flexibility to accommodate future climate variations.

Introduction: The world is facing an economic crisis that has led to high energy prices in the EU. These high energy prices have been a contributing factor to the challenging economic situation in Sweden, affecting businesses, industries, and households. EU countries have limited access to energy and rely mostly on imports. The key objective is to reduce these costs through the utilization of renewable energy resources. Geothermal ventilation, in particular, is an efficient and promising source. However, this system has not yet been implemented in Sweden. The aim of this study is to investigate and analyze the effectiveness of horizontal ground geothermal ventilation systems in the context of Swedish conditions.Method: This study includes quantitative and qualitative data from a case study. Data collection involved literature study, interviews with various stakeholders, and simulations using Ansys software to analyze air flows and temperature conditions.Results: This section presents the results of a comprehensive study on basic geothermal ventilation in villas, carried out in accordance with Swedish environmental regulations. Interviews with representatives from ventilation companies and Jönköping municipality showed mixed opinions about the system's potential. While some expressed interest and approval due to energy savings and environmental adaptation, others had concerns about profitability and cost-effectiveness. Testing the system's efficiency using thermal exchange simulation software showed lower-than-expectedresults, indicating the need for further improvements. However, despite its lower efficiency, the geothermal ventilation system was still considered an environmentally friendly alternative to conventional methods, helping to reduce the environmental impact of the construction industry.Analysis: Ground geothermal ventilation system meets Swedish environmental standards and contributes to energy savings in new buildings. Although the system meets the stan

Introduction: The world is facing an economic crisis that has led to high energy prices in the EU. These high energy prices have been a contributing factor to the challenging economic situation in Sweden, affecting businesses, industries, and households. EU countries have limited access to energy and rely mostly on imports. The key objective is to reduce these costs through the utilization of renewable energy resources. Geothermal ventilation, in particular, is an efficient and promising source. However, this system has not yet been implemented in Sweden. The aim of this study is to investigate and analyze the effectiveness of horizontal ground geothermal ventilation systems in the context of Swedish conditions.Method: This study includes quantitative and qualitative data from a case study. Data collection involved literature study, interviews with various stakeholders, and simulations using Ansys software to analyze air flows and temperature conditions.Results: This section presents the results of a comprehensive study on basic geothermal ventilation in villas, carried out in accordance with Swedish environmental regulations. Interviews with representatives from ventilation companies and Jönköping municipality showed mixed opinions about the system's potential. While some expressed interest and approval due to energy savings and environmental adaptation, others had concerns about profitability and cost-effectiveness. Testing the system's efficiency using thermal exchange simulation software showed lower-than-expectedresults, indicating the need for further improvements. However, despite its lower efficiency, the geothermal ventilation system was still considered an environmentally friendly alternative to conventional methods, helping to reduce the environmental impact of the construction industry.Analysis: Ground geothermal ventilation system meets Swedish environmental standards and contributes to energy savings in new buildings. Although the system meets the stan

This review paper summarizes recent developments regarding geothermal exploitation using coaxial deep borehole heat exchangers (DBHE). Specifically, this study focuses on field tests, analytical and semi-analytical approaches, and numerical simulations. First, field tests and applications of coaxial DBHE are summarized and future work for the field tests is suggested. Then, the ongoing analytical and numerical modeling approaches on coaxial DBHE are evaluated regarding the capability and incapability of describing physical behaviors. Lastly, key factors for the design of coaxial DBHE are summarized and discussed based on collected results. Regarding field tests, future work should focus more on (1) long-term performance; (2) effect of groundwater flow within formation and fractures; (3) technology for larger diameter boreholes; (4) new and cheap materials for insulated inner pipe; (5) treatment of fluid, pipe wall, and different working fluid; (6) economic analysis of coaxial DBHE-based geothermal power plant. As for the analytical methods and numerical simulations, it is important to consider the dependence of fluid and formation properties on pressure and temperature. Besides, verification and calibration of empirical models for working fluids other than water such as CO2 should be performed based on laboratory and field tests. Different borehole properties and pump parameters should be optimized to obtain the maximum thermal power of a coaxial DBHE, and an insulated inner pipe is recommended by many researchers. An intermittent working pattern of the DBHE could be more realistic when modeling a DBHE. To further improve the performance of coaxial DBHE, continuous research to enhance heat transfer and working fluid performance is still important.

One of the biggest challenges in developing renewable energy, such as geothermal energy, is understanding how to be accepted by the community impacted by the development. However, very few studies attempted to numerically express the time-dependent process of social acceptance in renewable energy projects. We quantify how social acceptance for a geothermal energy project is acquired from the involved communities. First, we present a compartment model for simulating how the numbers of supporters and opponents of developing geothermal energy change over several decades. We then introduce a time-varying index, an effective susceptibility number (R_e), similar to the effective reproduction number used in modeling epidemiologic phenomena. Second, we share our findings about the history of the number of supporters and opponents of the geothermal power plant construction project in Japan based on the articles published in local and national newspapers between 1970 and 2020. Our simulation results show that the proposed compartment model could predict documented changes in the numbers of supporters and opponents. Also, the effective susceptibility number (R_e) could represent the frequency of interactions among the community members. We suggest that an effort should be made to avoid having R_e < 1 in the community, to maintain a steady increase in the number of supporters to eventually acquire the social acceptance of a geothermal energy project. Our simple but novel approach using the compartment model will help better understand the dynamics and predict the community acceptance process in geothermal and other renewable energy projects.

Reducing energy costs in Europe is more challenging than before due to extreme price increases. The use of local renewable energy sources is one way to contribute to this effort. In the case of spa resorts, the use of heat from hot springs for therapeutic baths is an option. It is necessary to cool down this thermal mineral water to a temperature acceptable to the human body. However, due to the high mineral content of this water, heavy fouling can be a problem for conventional heat exchangers. The purpose of this study is to identify the suitable cooling technology in terms of required cooling capacity and waste heat recovery capability. The cooling technology was selected on the basis of a literature search. A pilot cooling unit consisting of vacuum cooler and plate heat exchanger was designed and tested in a real spa resort for six months. Both selected technologies have demonstrated the ability to cool thermal mineral water in long-term operation, as well as the possibility to utilize waste heat for domestic hot water heating. However, fouling problems occur in the plate heat exchanger. The vacuum cooler demonstrated greater operational robustness and resistance to encrustation.

Geothermal energy is a cleaner and more sustainable source of power, which plays a key role in the transition to a low-carbon economy. Sustainable and safe exploitation of geothermal resources, however, depends on our ability to understand and manage the associated seismic risks. In 2018, Nature's Heat geothermal project began operations in Kwintsheul, Netherlands, aiming to supply heat to 64 hectares of greenhouses. Between July and October 2019, a temporary seismic array was installed to monitor for possible seismic activity at the site. Microseismic moment-tensor inversion is a valuable tool for understanding the mechanics and structure of geothermal reservoirs, and for optimizing their exploitation. It can be challenging, though, to apply this technique when there are high levels of ambient seismic noise, as is often the case in geothermal operations in densely populated areas. In this study, we evaluate the feasibility of inverting the centroid moment tensor of microseismic events in Kwintsheul, using probabilistic moment-tensor inversions. We first test the probabilistic inversion using synthetic recordings of ambient seismic noise, after which we apply the technique to the low-magnitude (Md=0.16) event recorded on July 14, 2019. Our results give insight into the challenges and limitations of applying moment-tensor inversion to low-magnitude events in the context of geothermal operations in the Netherlands., Applied Geophysics and Petrophysics

Ground source heat pump (GSHP) technology has gained significant attention as a viable solution for the heating, ventilation, and air conditioning (HVAC) of buildings. One of the factors that can impact the performance of GSHP systems is the soil moisture content. In this study, an innovative approach, referred to as soil impedance topology, is introduced as an alternative to traditional methods for measuring soil moisture content in geothermal heat pump systems. This method is inspired by pipeline grid utilizes impedance measurement, which provides a direct measurement of soil moisture content without the need for sensors. The study also proposes a changing rule of impedance with varying moisture content, where capacitance increases and resistance decreases when the soil moisture content is less than 20% but stabilizes beyond a water content of 20%. The accuracy of the topological mechanism prediction method is high, as demonstrated through the verification of the Smith circle and measured data. However, it is noted that the performance may be insufficient in the high frequency band and high soil moisture content. The use of impedance topology provides a more accurate and reliable method for measuring soil moisture content as well as for modeling and predicting heat transfer rates and system performance. This technology has strong potential to improve efficiency, reduce energy costs, and enhance the environmental sustainability of geothermal heat pump systems.

In the sedimentary bedrock of southwest Scania, located in the southernmost part of Sweden, there are several low-enthalpy Mesozoic sandstone aquifers situated at different depths. These aquifers collectively hold the potential for direct-heat geothermal utilization. Given the energy supply challenge across Europe, there is a growing need to characterise the geothermal resources and quantify their energy content. Despite this demand, the assessment of geothermal resources in Sweden has not been performed to any larger extent in comparison to assessment studies of similar geothermal aquifers in Europe. This limitation is concerning, as these aquifers should be acknowledged as national renewable energy assets. This study presents a first-ever geothermal assessment using the stored heat “Heat-In-Place” (HIP) method on the Cretaceous Arnager Greensand over southwest Scania. The results present a set of maps that illustrate the stored heat in the subsurface for the Arnager Greensand, and additional maps detailing the spatial distribution, such as the depth to the formation, thickness, and reservoir temperature. The Arnager Greensand stores a total of 3270 PJ in a range of 1.25 – 4.53 GJ/m2 over SW Scania. The stored heat values are slightly higher with a total of 3610 PJ in the range of 1.37 – 4.99 GJ/m2 in the rock matrix and reservoir fluids separately. The produced maps show the regional geothermal signatures of the Arnager Greensand where the stored heat is particularly marked in the southern parts of the region covering the Falsterbo Peninsula. The relatively greater stored heat in this area can be attributed to the greater thickness of the Arnager Greensand formation. The region from the Falsterbo Peninsula to Malmö and Trelleborg demonstrates relatively greater stored heat values, offering potential for further local geothermal investigations. Its proximity to urban and industrial areas significantly enhances the feasibility of integrating a well-doublet system in

Geothermal energy is considered as renewable energy and environmentally friendly. However, during the exploration process, a Geothermal Power Plant (PLTP) commonly leaves various environmental problems, such as destroyed conservation areas, floods, landslides, and reduced clean water sources. The impact of the Baturraden Geothermal Power Plant exploration also has resulted in water pollution of the Mengaji and Prukut rivers, which eventually could no longer be used as clean water sources for people’s daily lives, especially women. This PLTP Baturraden case study aimed to observe the relationship between environment, gender, and geothermal energy, especially the impact of geothermal power plant exploration. This research used a qualitative method by collecting primary data through interviews and secondary data through literature studies. This study showed that PLTP Baturraden exploration had negative impacts in 2017-2018 water pollution of Prukut River as a clean water source and directly affected women in Panembangan, Cilongok. Using a gender analysis, environmental destruction is analyzed through three things, namely formal and informal constraints, division of labor, and access to resources which have a worsening impact on women.

In a transition to a sustainable energy system, governmental actors initiate participatory processes to gain better insights in questions and concerns of stakeholders, or to create support for decisions. Those participatory activities are embedded in institutionalized and formal decision making procedures. Participatory approaches promise to function as alignment mechanisms between those policies and society. The aim of this paper is to contribute to more successful alignment mechanisms. Based on a thematic analysis of 18 interviews and approximately one hundred policy documents, we relate stakeholders' uncertainties about ultra-deep geothermal energy to their preferred modes of participation. These stakeholders were (in)directly involved in the Dutch Green Deal program, in this case the Green Deal Geothermal Energy in the province North Brabant. Based on the analysis, we identify four participatory storylines and develop a more systemic view on different participatory activities: ‘participatory repertoires’. We conclude that unproductive power-politics between different political-administrative levels, and emerging local and wider publics that hamper alignments, may be prevented. This can be done by prioritizing societal dialogue on normative uncertainties in a range of combinations with local dialogue on normative, conceptual uncertainties, and with national or local joint fact finding on informational uncertainties.

Natural fractures play a crucial role in many sustainable subsurface applications, particularly in reservoirs with low primary porosity and permeability. Therefore, fracture analysis has become a fundamental aspect of geosciences, often starting with fracture interpretation from borehole image logs. It has been widely recognized that interpretations come with uncertainties; nevertheless, there is a current lack of both quantitative and qualitative understanding regarding differences among interpretations. This study aims to address this gap, by performing a statistical analysis on five interpretations of the same well, highlighting their differences and similarities. Based on the results from the analysis, a workflow was created to reduce uncertainties in fracture interpretations from image logs. The created workflow was then applied to two wells in the Geneva Basin, Switzerland; associated with a geothermal project aiming to produce heat and electricity from the Upper Cretaceous limestone rocks. Research has shown that these rocks form a tight reservoir, and fluid flow will rely on the presence of fracture networks. In the two wells, a total of eight fracture sets were defined based on movement and relative chronology, and used to reconstruct the fracture history of the basin. This led to the identification of four Mesozoic to Cenozoic stress regimes: 1) a normal or strike-slip regime, 2) a NE-SW reverse regime, 3) a normal regime, and 4) a NW-SE reverse regime. The latter is considered the main deformation event of the region: the Late Miocene fold-and-thrust tectonics. In the Geneva Basin, this event is represented by a pair of NE-SW striking conjugates, which forms the majority of observed fractures. The fifth fracture set is believed to be fault-related and was only observed in one of the wells. Beyond the regional implications, this study emphasizes the importance of uncertainty reduction in the early stages of fracture analysis, and its eff, GEothermie2020 project, Geo-Energy Engineering

The CO\textsubscript{2} Plume Geothermal (CPG) Consortium was created in March 2023 to demonstrate the potential and technical feasibility of CO\textsubscript{2} Plume Geothermal at candidate sites in an integrated academic and industry synergistic collaboration. Following 12 years of theoretical CPG research, the consortium will execute a field demonstration in order to de-risk future commercial scale projects. Tracer campaigns performed during a field demonstration can provide information on how the plume evolves over time, which may be extrapolated in time and space to estimate the long-term, large-scale heat recovery potential for commercial CPG projects. Gas tracers, however, have not yet been employed for these purposes. Here we define the optimal tracer field campaign recommendations based on reservoir simulations of the Sleipner field in offshore Norway. We found that the determination of CO\textsubscript{2} plume development and sweep conformance was optimized using 7 tracers (N=7) in one-month intervals (dt=1). Additionally, we found that our homogeneous model possesses the largest sweep of the three models, as a uniform permeability permits greater flow of CO\textsubscript{2} at greater depths in the reservoir. Based on our results, we recommend injecting 35 kg (5 kg each) of 7 perfluorocarbon tracers over 5-6 hours in one-month intervals for determination of CO\textsubscript{2} plume development. However, for different reservoirs of interest, similar simulations, such as used in this study, should be run to identify a suitable number of tracers (N) and a suitable injection interval (dt) for determining CO\textsubscript{2} plume development and convergence for that site. From our findings, a tracer campaign would help reduce uncertainty in modelling, predictions and history-matching and improve understanding of sweep efficiency and long-term heat recovery. Tracer campaigns performed during a CPG pilot demonstration can then enhance the sweep efficiency as, Applied Geophysics | IDEA League

In the geothermal exploration well, NLW-GT-01, in the West Netherlands Basin, a very tight reservoir with low porosity (≤5.0%) and matrix permeability (≤ 0.1mD) has been encountered in the Main Buntsandstein Subgroup. The impact of natural fractures, which can significantly impact fluid flow in tight reservoirs, has been studied. However, there is a lack of consensus in different studies on the fracture classification. In this study, a re-evaluation is performed of the well data of the NLW-GT-01 and VAL-01 wells. An analysis comparing core, geophysical, and image logs is performed to document the drivers and characteristics of natural fracture distribution in the WNB and investigate the geological and geomechanical parameters influencing the development of fractures in the Main Buntsandstein Subgroup. On the core of NLW-GT-01 and VAL-01, five types of fractures are classified veins, joints, Mode II fractures, stylolites and drilling-induced fractures. The natural fractures have a dominant NW-SE strike orientation. The drilling-induced fractures and the borehole breakouts indicate a NE-SW oriented in-situ minimum stress and an NW-SE oriented maximum stress. The natural fractures are favourably oriented to be open based on their orientation compared to the in-situ stress orientation. The fractures are associated with large-scale tectonic events. During the burial of the formation related to the extensional phase of the WNB during the Mesozoic, veins, joints, conjugate fractures, and stylolites could be formed. During the inversion of the basin in the Late Mesozoic-Cenozoic, tectonic stylolites could have been formed, and the previously formed conjugate fractures could have been reactivated. Natural fractures are concentrated in more heterolithic intervals of the VAL-01 and NLW-GT-01 wells in both image logs and cores. These heterolithic sections display alternations of medium sandstones with silt- and claystones. The identification, Geo-Energy Engineering

The level of advancement in the understanding of the mechanical properties of volcanic rocks is comparatively lower than that of sedimentary rocks. As part of the SUCCEED Project (Synergetic Utilisation of CO2 Storage Coupled with Geothermal Energy Deployment), which aims to investigate the feasibility of injecting captured and produced CO2 into the reservoirs to enhance geothermal production and achieve permanent CO2 storage at the Hellisheiði Geothermal Field in Iceland, this experimental research provides significant insights into the petrophysical and mechanical properties of the volcanic rocks collected from surface outcrops. The subsurface in Hellisheiði is mainly built up of hyaloclastite formations and interglacial basaltic lavas. During a field campaign samples were collected in different outcrops, ensuring that the samples were of high quality and sufficiently diverse to enable comprehensive analysis. Four samples per block and rock type have been prepared from the collected blocks, and they have been subjected to different laboratory tests to evaluate their petrophysical properties, such as porosity, density, and permeability, and their geomechanical behavior, using Unconfined Compression Test (UCS), Active-Source Acoustic Test, and Splitting Tensile Strength Test. Additionally, laboratory experiments have been conducted to investigate the impact of rapid cooling on rock damage due to thermal fracturing. The results show that there are interdependent relationships between porosity, bulk density, ultimate strength, Young's modulus, and wave velocities that can be observed when considering average values per rock. The rocks studied showed a negative correlation between porosity and other parameters and a direct correlation between ultimate strength and Young's Modulus. When examining individual rock samples, no significant correlations were observed between porosity and other parameters, however, those correlations where evident when comparing between diffe, SUCCEED Project, Applied Earth Sciences

It is universally acknowledged that climate change brings widespread attention to solar greenhouse plant carbon sequestration. Suitable technologies in solar greenhouses were, are, and will be play a leading role in this vital transition. The primary aim of this research is to examine the energy efficiency and carbon sequestration potential of a solar-assisted ground-source heat pump (SAGSHP) heating system. This hybrid system, which integrates a horizontal ground-source heat pump (GSHP) system with PVT and heat storage, can efficiently fulfill the heating demands of a greenhouse and function as a positive energy building. Four plants include cucumber, tomato, cowpea, and lettuce were selected to compare the carbon absorption effects. Results show that the hybrid system outperforms conventional systems, with a coefficient of performance (COP) of 6.71 during peak hours and PVT efficiency over 57.88%, which effectively meet the heat load of the greenhouse and keep the indoor heat comfortable. In addition, for the carbon sequestration potential of four plants, tomato exhibited the highest photosynthetic carbon sequestration of 3522 kgCO2·m−2. Cowpea showed the strongest daily carbon sequestration capacity at 26.86 gCO2m−2d−1 and better economic income. Through the application of this enhanced solar greenhouse, people can enhance the utilization of solar energy, establish flexible interaction between energy and information flow, and make a promising option for sustainable building design.

The utilization of geothermal energy is becoming increasingly important in the current transition towards sustainable energy sources. Among the various methods of utilizing geothermal energy, the use of hybrid geothermal power plants that exploit CO2 fluid for preheating in electricity generation has been identified as an attractive approach. Additionally, the shallow ground source heat pump (SGSHP) has been proven to be superior in previous experimental studies. However, the full-scale utilization of geothermal energy, through generating electricity from geothermal power plants and applying waste heat with SGSHPs for auxiliary heating, needs further exploration. This study proposes a novel CO2 hybrid geothermal system that incorporates a GSHP heating system. The hybrid geothermal system uses CO2 as the underground working fluid, and the electricity and waste heat are used to assist the GSHP for heating, ventilation, and air conditioning. The proposed system can produce 11.41 MW of electricity, 80 °C of hot water, and 34.76 MW of cold energy by driving 50 MW of the geothermal heat. Through a comprehensive analysis of the economy, energy, exergy, and environment, the results demonstrate that the maximum exergy damage of the refrigeration power cycle is 37999.33 kW, which has the highest exergy losses. The exergy loss of the steam turbine heat power conversion in the geothermal power generation process is the highest, but this loss can be effectively reduced through heat integration. The optimal cooling temperature of the coupled system should be set at 8 °C, and it has a good investment prospect. In summary, the CO2 hybrid geothermal system can realize effective cogeneration and fully utilize geothermal energy. Therefore, it has great potential to contribute to the transition towards a sustainable energy future.

Reservoir impoundment is usually accompanied by induced/triggered seismicity. The rise in the number of planned hydropower plants requires improving the understanding of the causes of this induced/triggered seismicity, which eventually could serve to propose mitigation measures to reduce the induced/triggered-seismicity risk. We investigate the case of reservoir-triggered seismicity at Nova Ponte, Brazil, where triggered seismicity started shortly after reservoir impoundment, with the maximum magnitude of M3.5 when reaching the highest water level on the dam, and followed by delayed seismicity, with the largest earthquake being a M4.0 about 4.5 years after impoundment. We have built a hydro-mechanical fully-coupled numerical model reproducing the T shape of the reservoir and including the three geological layers placed below the reservoir down to 10 km depth. Simulation results serve to identify the nodal plane, from the two nodal planes of the proposed focal mechanism, which nucleated the seismicity of the M3.5 earthquake: a vertical, E-W-oriented strike-slip fault with a reverse-displacement component. The initial seismicity was triggered by the undrained response of the subsurface to the loading of the reservoir. We also find that the delayed seismicity was triggered by pore pressure diffusion, bringing a critically oriented vertical fault to failure conditions. The vertical permeability to allow the pore pressure perturbation to reach the depth of the M4.0 earthquake, i.e., 3 km depth, in 4.5 years is 6.6·10-15 m2, two to three orders of magnitude higher than the expected permeability of the host rock, a low-permeability mica-schist. We contend that hydro-mechanical models are a useful tool to understand the triggering mechanisms of reservoir-triggered seismicity.

Hydrogen is attracting global attention as a key future low-carbon energy carrier which could replace hydrocarbon usage in transport and fuel-intensive industry. However, to supply energy in the TWh-range necessary for Net Zero it requires storage at much larger volumes than the currently deployed surface tanks or salt caverns storage. A potential solution for large-scale hydrogen storage are porous saline aquifers and depleted hydrocarbon fields. This perspective is promising but remains technically challenging given the lack of active hydrogen storage knowledge and experience. Here we present the SHINE (Safe underground Hydrogen storage IN porous subsurface rEservoirs) project, recently funded under the Horizon 2020 MSCA Doctoral Networks scheme, which is a consortium of five Universities/Research Institutes and six energy companies with the aim of exploring the feasibility of hydrogen storage in porous reservoirs, addressing the technical, geological, biological, hydrogeological and geomechanical challenges related to hydrogen storage in subsurface porous reservoirs. For this purpose, 10 new doctoral students will be trained to tackle this scientific challenge. We will introduce the main concepts behind SHINE, the research package structure which aims at integrating analytical, monitoring and computational techniques to analyse how hydrogen may react with the subsurface minerals, fluids and microbial community potentially affecting the storage operations. SHINE will also model the stress field changes across hydrogen reservoir/caprocks and monitor their geomechanical response during repeated injection/production cycles. The expertly trained cohort of young research scientists resulting from the SHINE consortium will significantly enhance and improve our understanding of this underground storage strategy. This will support the implementation and de-risking of potential porous rock hydrogen storage projects by providing the necessary insights into this large scale

Hydrogen is attracting global attention as a key future low-carbon energy carrier which could replace hydrocarbon usage in transport and fuel-intensive industry. However, to supply energy in the TWh-range necessary for Net Zero it requires storage at much larger volumes than the currently deployed surface tanks or salt caverns storage. A potential solution for large-scale hydrogen storage are porous saline aquifers and depleted hydrocarbon fields. This perspective is promising but remains technically challenging given the lack of active hydrogen storage knowledge and experience. Here we present the SHINE (Safe underground Hydrogen storage IN porous subsurface rEservoirs) project, recently funded under the Horizon 2020 MSCA Doctoral Networks scheme, which is a consortium of five Universities/Research Institutes and six energy companies with the aim of exploring the feasibility of hydrogen storage in porous reservoirs, addressing the technical, geological, biological, hydrogeological and geomechanical challenges related to hydrogen storage in subsurface porous reservoirs. For this purpose, 10 new doctoral students will be trained to tackle this scientific challenge. We will introduce the main concepts behind SHINE, the research package structure which aims at integrating analytical, monitoring and computational techniques to analyse how hydrogen may react with the subsurface minerals, fluids and microbial community potentially affecting the storage operations. SHINE will also model the stress field changes across hydrogen reservoir/caprocks and monitor their geomechanical response during repeated injection/production cycles. The expertly trained cohort of young research scientists resulting from the SHINE consortium will significantly enhance and improve our understanding of this underground storage strategy. This will support the implementation and de-risking of potential porous rock hydrogen storage projects by providing the necessary insights into this large scale

Numerous geoenergy projects (geologic carbon storage, geothermal systems, gas storage or hydraulic fracturing) involve injection of fluids at depth. The resulting changes in effective stress often induce (micro)seis- micity. While damages are usually minimal, public perception may be dam- aged if seismicity is perceived, thus compromising the project viability. The problem is worsened by the numerous processes involved (hydraulic, me- chanical, thermal, and often chemical), by the fact that they are intimately coupled, and by the diversity of failure settings. As a result, understanding is hard, which hinders not only numerical simulation, but also the design and operation of remediation and mitigation actions. We first review cou- pled process, from the traditional impact of pore pressure increase on sta- bility, to stress transfer driven by pressure gradients or thermal contrac- tion. This leads to a broad view of the induced seismicity operational mechanisms, which we summarize in five operational failure mechanisms (i.e., directly linked to fluid operation): pressure buildup, pressure dissipa- tion, displacement transfer, thermal contraction, and buoyancy. Under- standing them is needed to move beyond the traditional traffic light system into active pressure management to control induced seismicity.

Hydroshearing, or shear stimulation, is recognized as the main method to exploit geothermal energy in hot low-permeability crystalline rocks at depth. It consists of enhancing permeability via injection-induced shear slip and dilation of preexisting fractures. , . Hydroshearing usually causes some induced microseismicity, sometimes of sufficient magnitude to be felt on the surface. Thus, high pressure fluid injection to enhance fracture permeability should be made carefully to avoid inducing earthquakes above the acceptable magnitude.

Fluid injection-induced earthquakes involve a series of complex physical processes. Evaluating these processes at the basin scale requires an amount of input data and a super computational ability to solve in near-real time risk analysis, which remains the most critical challenge in geo-energy related applications. Although the current computational tools can achieve a good simulation for the field scale problems, they are far away from the requirements of the basin scale analysis. Alternatively, we can apply verified analytical solutions of certain processes to speed the whole calculations when moving from the field to the basin scale. With this in mind, we adopt the analytical solutions for pore pressure diffusion and stress variations due to fluid injection into the reservoir. With the superposition principle, the analytical solutions can address the coupling problem of multi-injection wells at the basin scale. We then assess faults stability and the associated induced seismicity potential using the hydro-mechanical perturbations throughout the basin computed analytically. To handle the uncertainty of geological properties, including the fault and reservoir geometries, hydraulic and mechanical properties, we perform Monte Carlo simulations to analyze their effects on induced seismicity potential. Such comprehensive parametric space analysis currently represents an insurmountable obstacle to be solved numerically, even calculating the problem in parallel. We propose a feasible methodology to mitigate the magnitude of induced seismicity, and even to avoid large earthquakes for subsurface energy-related projects, based on the results obtained both at the field and basin scales. This development will represent a great tool for risk evaluation of induced earthquakes not only in the period of site selection, but also in the whole lifetime of geo-energy projects.

The majority of available climate change mitigation pathways, targeting net-zero CO2 emissions by 2050, rely heavily on the permanent storage of CO2 in deep geologic formations at the gigatonne scale. The spatial and temporal scales of interest to geologic carbon storage (GCS) raise concerns about CO2 leakage to shallow sediments or back into the atmosphere. The assessment of CO2 storage performance is subject to huge computational costs of numerically simulating CO2 migration across geologic layers at the basin scale and is therefore restricted in practice to multi-century periods. Here, we present a computationally affordable and yet physically sound model to understand the likelihood of CO2 leakage over geologic time scales (millions of years) (Kivi et al., 2022). The model accounts for vertical two-phase flow and transport of CO2 and brine in a multi-layered system, comprising a sequence of aquifers and sealing rocks from the crystalline basement up to the surface (a total thickness of 1600 m), representative of a sedimentary basin. We argue that the model is capable of capturing the dynamics of CO2 leakage during basin-wide storage because the lateral advancement of CO2 plume injected from a dense grid of wellbores transforms into buoyant vertical rise within a short period after shut-in. A critical step in the proposed model is its initialization, which should reproduce the average CO2 saturation column and pressure profiles. We initialize the model by injecting CO2 at a constant overpressure into an upper lateral portion of the target aquifer while the bottom boundary is permeable to brine, resembling brine displacement by CO2 plume or leakage at basin margins. The optimum model setting can be achieved by adjusting the brine leakage parameter through calibration. We solve the governing equations using the finite element code CODE_BRIGHT. Discretizing the model with 7,100 quadrilateral elements and using an adaptive time-stepping scheme, the CPU time for the s