Geothermal Resources Research Articles

Recent progress and emerging technologies in geothermal energy utilization for sustainable building heating and cooling: a focus on smart system integration and enhanced efficiency solutions

Geothermal energy has gained prominence as a sustainable solution for heating and cooling, driven by technological innovations and the growing global demand for energy efficiency. Geothermal systems, particularly ground-source heat pumps (GSHPs), exhibit high energy efficiency, with coefficients of performance (COP) ranging from 3.5 to 6.0, while deep geothermal systems operate at temperatures of 50°C–200°C, supporting both power generation and large-scale heating applications. Enhanced Geothermal Systems (EGS) use hydraulic, chemical, and thermal stimulation to extract heat from low-permeability formations, significantly expanding the applicability of geothermal resources beyond traditional hotspots. Geothermal heat pumps are capable of achieving energy efficiency levels of 300%–600%, reducing CO2 emissions by 50%–70% when compared to fossil fuel-based HVAC systems. However, installation costs for GSHPs range from $2,500 to $5,000 per kW, while deep geothermal systems require higher capital investments. Despite these initial costs, operational expenses remain competitive at $0.01–$0.03 per kWh, and geothermal plants exhibit high-capacity factors of 70%–90%, outperforming solar (20%–30%) and wind (30%–50%) in terms of energy production consistency. The return on investment (ROI) for geothermal systems typically occurs within 5–15 years, depending on location and system scale. The integration of smart technologies, such as artificial intelligence (AI), machine learning (ML), and the Internet of Things (IoT), further enhances the efficiency of geothermal energy systems by enabling real-time monitoring, predictive maintenance, and load forecasting, optimizing overall performance and longevity. Hybrid systems, combining geothermal energy with solar, wind, and thermal energy storage, improve grid stability and further enhance energy efficiency. Despite challenges such as geological constraints, high initial costs, and regulatory barriers, policy frameworks and government incentives play a vital role in promoting the expansion of geothermal energy. The global geothermal capacity surpassed 16 GW in 2023 and is projected to exceed 24 GW by 2030, with significant deployments in countries like the U.S., Indonesia, Kenya, the Philippines, and Turkey. Notable geothermal projects include the Olkaria Geothermal Power Plant (800 MW, Kenya), The Geysers (1.5 GW, United States), Hellisheidi (303 MW electricity, 400 MW thermal, Iceland), and the Yangbajain Geothermal Power Station in China (25.5 MW and 100 GWh annual generation). As nations aim for carbon neutrality and energy security, geothermal energy is poised to play a crucial role in achieving sustainable energy transitions and mitigating climate change.

Separation of Regional and Residual Anomalies Using GGMPlus Gravity Data in Panti Sub-District, West Sumatra

This study addresses the limited application of GGMPlus satellite gravity data for regional and residual anomaly separation in geothermal exploration within Indonesia. The research aims to separate and analyze gravity anomalies to elucidate subsurface geological structures in Panti District, Pasaman Regency, West Sumatra. A quantitative-descriptive approach with an exploratory design was employed, utilizing secondary gravity data from the GGMPlus model comprising 4,537 measurement points at 200-meter intervals. Data processing involved Bouguer correction, Fourier transformation, and the application of a bandpass filter using Oasis Montaj software. The complete Bouguer anomaly in the study area ranges from –37.5 to –25.6 mGal. Frequency-based separation yielded regional anomalies ranging from –37.3 to –25.8 mGal, while residual anomalies varied between –0.77 and 0.72 mGal. The residual anomalies are interpreted as responses from shallow subsurface features, including sedimentary rocks and potential geothermal reservoirs. In contrast, the regional anomalies are associated with deeper geological structures, such as faults and intrusive bodies. These findings demonstrate that frequency-domain filtering provides an effective means of enhancing the interpretability of satellite-derived gravity data in geothermal investigations. The study confirms the utility of GGMPlus data and spectral filtering techniques in delineating subsurface targets and improving geophysical assessments for geothermal resource exploration.

Preparation of copper mine tailings-based geopolymers as thermal storage functional backfill materials.

Preparation of copper mine tailings-based geopolymers as thermal storage functional backfill materials.

Integrated structural analysis for geothermal exploration: A new protocol combining remote sensing and aeromagnetic geophysical data.

Geothermal energy holds significant potential as a sustainable and clean source, yet efficient exploration methodologies remain critical for identifying viable sites. This paper presents a novel protocol for the identification and analysis of structural lineaments in geothermal fields, crucial for coherent geothermal exploration. The approach integrates surface data from remote sensing and data from airborne magnetic geophysical surveys that provide information on the subsurface structures, to analyze structural lineament density analysis, orientation, and high permeable zones, and assess geothermal potential. By combining information from these two sources, the study demonstrates the relationships between structural lineaments and areas of high permeability, shedding light on geothermal resource distribution. This twofold structural analysis not only enhances our ability to identify potential geothermal sites but also contributes to a deeper understanding of the geological factors influencing geothermal reservoirs. This integrated approach advances geothermal exploration in line with the global shift towards sustainable energy.•The straightforward nature of the approach enables its versatile application for predicting various geological processes beyond geothermal exploration.•The application of this protocol is accessible to a broader audience of researchers, as it does not require knowledge of programming language.•The results obtained from this approach demonstrate high predictive performance, underscoring reliability in identifying and analyzing structural elements in geothermal fields.

Delineating crustal domains favorable for exploring enhanced geothermal resources based on temperature, petro- and thermophysical properties of rocks: A case study of the Soultz-sous-Forêts geothermal site, France

Delineating crustal domains favorable for exploring enhanced geothermal resources based on temperature, petro- and thermophysical properties of rocks: A case study of the Soultz-sous-Forêts geothermal site, France

Investigation of evaluation models for geothermal resources and intermittent operation/cycle thermal storage mode in closed coal mines

Investigation of evaluation models for geothermal resources and intermittent operation/cycle thermal storage mode in closed coal mines

Prospects and challenges for utilisation of low- to medium-temperature geothermal resources in Tanzania

Prospects and challenges for utilisation of low- to medium-temperature geothermal resources in Tanzania

New assessment of geothermal resources in Morocco: Evaluation of the curie point depth method using magnetic data for geothermal gradient and heat flow estimation

New assessment of geothermal resources in Morocco: Evaluation of the curie point depth method using magnetic data for geothermal gradient and heat flow estimation

Parametric analysis of geothermal reservoir performance in Mesozoic sandstone formations within the North German Basin developed by multi-well systems

In the context of the heat transition in Germany, the decarbonization of the heating and cooling industry via renewable energy sources requires the usage of comprehensive strategies and novel engineering solutions. With regard to district heating in urban areas, middle-deep geothermal resources offer a great potential which has not been fully utilized yet due to the required minimum temperature of district heating networks, leading to the additional employment of industrial and high-capacity-power heat pumps. However, the controlling factors on the optimal and sustainable development of those middle-deep geothermal resources are not fully elucidated yet. By evaluating numerical approaches against analytical model solutions, this work systematically analyzes the impact of reservoir quality and operational controlling factors on the performance of Mesozoic sandstone reservoirs in the North German Basin (NGB) targeted by multi-well arrangements. For the first time, we compare in a comprehensive manner previous analytical model results with our numerical findings to characterize more broadly the quantitative influence of different controlling factors on the thermal breakthrough occurrence time, the maximum cooling rate after the occurrence of the thermal breakthrough and the end production temperature. Moreover, we especially focus and illustrate the controls on the behavior of the production temperature after the thermal breakthrough has occurred and conduct a one-factor-at-a-time (OAT) parametric sweep analysis with regard to the thermal utilization time or life span of a geothermal facility. Based on our numerical results, we set up a ranking scheme showing the influence of varying controlling parameters on the considered performance parameters. One of the striking findings of our scenario analysis relates to the thermal breakthrough occurrence time, which is 17 ± 3% higher for a geothermal doublet array compared to a single doublet. Yet, the maximum cooling rate of the production temperature after the thermal breakthrough is higher for the array layout, depending on the number of neighboring injection wells. Our comprehensive numerical study, therefore, illustrates in detail the complex thermo-hydraulic interaction of geothermal doublet arrays, the controls on the defined thermal lifetime as well as the optimization possibilities of middle-deep geothermal resources.

Modelling Geothermal Energy Extraction from Low-Enthalpy Oil and Gas Fields Using Pump-Assisted Production: A Case Study of the Waihapa Oilfield

As the energy sector transitions toward decarbonisation, low-to-intermediate temperature geothermal resources in sedimentary basins—particularly repurposed oil and gas fields—have emerged as promising candidates for sustainable heat and power generation. Despite their widespread availability, the development of these systems is hindered by gaps in methodology, oversimplified modelling assumptions, and a lack of integrated analyses accounting for long-term reservoir and wellbore dynamics. This study presents a detailed, simulation-based framework to evaluate geothermal energy extraction from depleted petroleum reservoirs, with a focus on low-enthalpy resources (<150 °C). By examining coupling reservoir behaviour, wellbore heat loss, reinjection cooling, and surface energy conversion, the framework provides dynamic insights into system sustainability and net energy output. Through a series of parametric analyses—including production rate, doublet spacing, reservoir temperature, and field configuration—key performance indicators such as gross power, pumping requirements, and thermal breakthrough are quantified. The findings reveal that: (1) net energy output is maximised at optimal flow rate (~70 kg/s for a 90 °C reservoir), beyond which increased pumping offsets thermal gains; (2) doublet spacing has a non-linear impact on reinjection cooling, with larger distances reducing thermal interference and pumping energy; (3) reservoirs with higher temperatures (<120°C) offer significantly better thermodynamic and hydraulic performance, enabling pump-free or low-duty operations at higher flow rates; and (4) wellbore thermal losses and reinjection effects are critical in determining long-term viability, especially in low-permeability or shallow fields. This work demonstrates the importance of a coupled, site-specific modelling in assessing the geothermal viability of petroleum fields and provides a foundation for future techno-economic and sustainability assessments. The results inform optimal design strategies and highlight scenarios where the geothermal development of oil and gas fields can be both technically and energetically viable.

Geothermal favourability in data-scarce regions: incorporating physical and socio-economic factors into a modified Play fairway approach, southwestern Yukon, Canada

Geothermal energy could be used to reduce or replace diesel for heating in remote northern communities. Geothermal development has primarily focused on shallow, high-temperature resources, but interest in low-temperature and deep geothermal resource exploration has increased as energy costs and climate change policy have evolved. Here, we evaluated the low-temperature geothermal favourability in southwestern Yukon by adapting Play fairway analysis to data-scarce regions. Play fairway analysis is a spatial statistical tool that uses a layered data approach to model favourability and risk assessments for resource exploration. Previous Play fairway analyses concentrate on the physical aspects of geothermal favourability: heat, permeability, and fluid availability. This study presents an overview of potential direct and indirect physical parameters that could be used in a geothermal Play fairway analysis in data-scarce regions and introduces the importance of considering socio-economic data in the exploration phase. The socio-economic controls are grouped into quantitative and qualitative parameters that describe population trends and community interests. The framework presented is then applied to a Play fairway analysis for southwestern Yukon. Based on the physical and socio-economic analysis, there is interest in exploring geothermal potential along the Denali fault near Duke River to support the community of Burwash Landing.

Review of artificial intelligence applications in geothermal energy extraction from hot dry rock

AbstractThe geothermal resources in hot dry rock (HDR) are considered the future trend in geothermal energy extraction due to their abundant reserves. However, exploitation of the resources is fraught with complexity and technical challenges arising from their unique characteristics of high temperature, high strength, and low permeability. With the continuous advancement of artificial intelligence (AI) technology, intelligent algorithms such as machine learning and evolutionary algorithms are gradually replacing or assisting traditional research methods, providing new solutions for HDR geothermal resource exploitation. This study first provides an overview of HDR geothermal resource exploitation technologies and AI methods. Then, the latest research progress is systematically reviewed in AI applications in HDR geothermal reservoir characterization, deep drilling, heat production, and operational parameter optimization. Additionally, this study discusses the potential limitations of AI methods in HDR geothermal resource exploitation and highlights the corresponding opportunities for AI's application. Notably, the study proposes the framework of an intelligent HDR exploitation system, offering a valuable reference for future research and practice.

DELINEATING RESISTIVITY VALUES OF POTENTIAL GEOTHERMAL AREAS ALONG THE BOGOR FAULT USING 2D MAGNETOTELLURIC INVERSION

Kepahiang Regency, located in an active fault zone, has great geothermal potential with an estimated capacity of up to 154 MW(e), making it a strategic renewable energy source to be developed. This research discusses the geothermal potential in the Kabawetan area, Kepahiang, Bengkulu. The main objective of this research is to evaluate the potential of geothermal resources around the Bogor segment by analyzing the subsurface structure using the Magnetotelluric inversion method and 2D resistivity modeling, in order to identify prospective geothermal reservoir zones. It can evaluate the potential of geothermal reservoirs in Kepahiang. The method used is the Magnetotelluric method, which utilizes the Earth's natural electromagnetic field to determine the distribution of resistivity in the subsurface. The results of 2D modeling with the MT method show potential zones associated with variations in subsurface thermal conditions and the presence of conductive clay minerals with resistivity values between 0.14-1 Ωm. These minerals are thought to be associated with the overburden (reservoir) of the geothermal system that has a depth of 2-4 km. The subsurface layer containing hot water and steam originating from heat emitted from the earth's core with a resistivity value of 2.5-45 Ωm at a depth of 1-4 km is thought to be caprock in the geothermal system, a resistivity value of 120-800 Ωm is thought to be hot rock with a depth between 1.5-10 km. It is estimated that there is a type of andesite rock that has been fractured as a reservoir of geothermal fluid. The findings of this research are expected to contribute to renewable energy as an alternative energy in the future, not only for energy needs but also for regional economic development through tourism and to support sustainable governance.

Geothermal resources in the northern Harrat Rahat volcanic field, Saudi Arabia: A drilling and field data assessment

Geothermal resources in the northern Harrat Rahat volcanic field, Saudi Arabia: A drilling and field data assessment

Scattering and Absorption Imaging of the Hengill High‐Temperature Geothermal Area, Southwest Iceland

AbstractWe applied 3D scattering and absorption imaging to the Hengill volcanic area (southwest Iceland), where high‐enthalpy geothermal reservoirs are presently harnessed. These techniques have shown the potential for detecting magmatic intrusions and fluid reservoirs in volcanic regions. Here, we target seismic scattering and absorption as proxies of the elastic and anelastic properties of the crust to understand their potential in areas of geothermal energy extraction. The harnessed Nesjavellir geothermal field was used as a benchmark to extend interpretation into non‐harnessed areas and provide better insight when evaluating exploitable geo‐resources. Shallow, high‐scattering anomalies mark the sub‐vertical Hengill fissure swarm. Deeper low‐scattering volumes likely highlight sub‐horizontal magmatic intrusions beneath the Hengill central volcano, whose less fractured volume acts as a barrier for the surrounding seismicity. At Nesjavellir, high absorption co‐located with high scattering volumes spatially correlates with previously detected high Vp/Vs volumes, suggesting the existence of fluid‐ and/or melt‐filled complex seismically active networks of faults and fractures. Our results suggest the presence of geothermal reservoirs in non‐harnessed areas (Mosfellsheiði and Ölkelduháls) shown by similar high‐absorption anomalies at depths comparable with the Nesjavellir geothermal resource. Scattering and absorption imaging complement more standard imaging techniques, improving interpretation in geothermal resource exploration.

Evolution of mesomechanical properties of granite minerals after high-temperature exposure

Hot dry rock (HDR) is a promising geothermal resource whose efficient development is crucial for alleviating energy shortages and achieving sustainable development. Accurate evaluation of the mechanical properties of HDR reservoirs is a key prerequisite for the efficient exploitation of geothermal resources. This study focuses on granite from the Gonghe in Qinghai, China, and systematically investigates the hardness, elastic modulus, fracture toughness, and creep behavior of four mineral components—quartz, orthoclase, plagioclase, and biotite—of granite under high-temperature conditions using nanoindentation and electron microscopy. The results show that biotite, due to its layered structure, undergoes penetration failure during micro-indentation, leading to significant differences in mechanical properties at the nano- and microscales. The mechanical properties of quartz and biotite at the microscale are temperature-sensitive, with a significant reduction in elastic modulus above 400 °C, primarily due to the α–β phase transition of quartz and the propagation of intergranular microcracks in biotite. Furthermore, creep tests reveal that biotite exhibits a creep rate an order of magnitude higher than the other minerals at the microscale, while quartz shows a significant decrease in creep parameters at high temperatures, suggesting that high-temperature thermal damage could exacerbate long-term deformation risks in reservoirs. This study reveals the response mechanisms of granite mineral mechanical properties to temperature variations, providing a theoretical foundation for the modification of HDR reservoirs and efficient geothermal development. The findings are significant for optimizing HDR geothermal extraction techniques, improving energy utilization efficiency, and ensuring engineering safety.

Present-day geothermal regime of the Junggar Basin, northwest China: Implication for hydrocarbon distribution and geothermal resources

Present-day geothermal regime of the Junggar Basin, northwest China: Implication for hydrocarbon distribution and geothermal resources

Utilizing geothermal botanical resources: Evaluating antiplanktonic and biofilm inhibitory effects of Jaboi area plant extracts

Context: Biofilm formation exacerbates infections and stimulates antimicrobial resistance, prompting a search for potent antimicrobial agents from diverse sources. Plants in unique environments, such as geothermal areas, offer prospective medicinal benefits due to their resilience against pathogens. Aims: To investigate the antiplanktonic and antibiofilm activities of five selected endemic plants from the geothermal area in Sabang comprising Hydnophytum formicarum Jack (Rubiaceae), Syzigium myrtifolium Walp (Myrtaceae), Aporosa octandra (Buch.-Ham. ex D.Don) Vickery (Phyllanthaceae), Memecylon coeruleum Jack (Melastomaceae) and Memecylon edule Roxb (Melastomaceae). Methods: The ethanol extracts were prepared using the maceration method. The identification of phytochemicals was carried out using TLC with specific spraying reagents. The volatile compounds were identified using GC-MS. The evaluation of antiplanktonic and antibiofilm activities was conducted by using the microdilution method against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 27853. Results: H. formicarum and M. edule extracts demonstrated the highest antiplanktonic activity against both bacteria. M. edule showed superior ability to prevent biofilm formation in S. aureus, while A. octandra exhibited the highest antibiofilm activity against P. aeruginosa. M. edule showed relatively potent antiplanktonic and antibiofilm activity. The GC-MS analysis revealed the presence of bioactive compounds from saturated and unsaturated fatty acids, phenols, terpenes, furan compounds, and sugars. Conclusions: M. edule from geothermal areas demonstrated potent antimicrobial activity against S. aureus biofilms and P. aeruginosa, indicating its potential against biofilm-related infections and antimicrobial resistance.

Spectral decomposition-based temperature and water-saturation-constraint dynamical simulations detect high-temperature geothermal energy resource

Spectral decomposition-based temperature and water-saturation-constraint dynamical simulations detect high-temperature geothermal energy resource

The geothermal resources of Vulcano Island (Aeolian Archipelago, Italy)

The geothermal resources of Vulcano Island (Aeolian Archipelago, Italy)