Geothermal Field Research Articles

Atomic Arrangement, Hydrogen Bonding and Structural Complexity of Alunogen, Al2(SO4)3·17H2O, from Kamchatka Geothermal Field, Russia

Alunogen, Al2(SO4)3·17H2O, occurs as an efflorescent in acid mine drainage, low-temperature fumarolic or pseudofumarolic (such as with coal fires) terrestrial environments. It is considered to be one of the main Al-sulphates of Martian soils, demanding comprehensive crystal-chemical data of natural terrestrial samples. Structural studies of natural alunogen were carried out in the 1970s without localization of H atoms and have not been previously performed for samples from geothermal fields, despite the fact that these environments are considered to be proxies of the Martian conditions. The studied alunogen sample comes from Verkhne–Koshelevsky geothermal field (Koshelev volcano, Kamchatka, Russia). Its chemical formula is somewhat dehydrated, Al2(SO4)3·15.8H2O. The crystal structure was solved and refined to R1 = 0.068 based on 5112 unique observed reflections with I > 2σ(I). Alunogen crystalizes in the P-1 space group, a = 7.4194(3), b = 26.9763(9), c = 6.0549(2) Å, α = 90.043(3), β = 97.703(3), γ = 91.673(3) °, V = 1200.41(7) Å3, Z = 2. The crystal structure consists of isolated SO4 tetrahedra, Al(H2O)6 octahedra and H2O molecules connected by hydrogen bonds. The structure refinement includes Al, S and O positions that are similar to previous structure determinations and thirty-four H positions localized for the natural sample first. The study also shows the absence of isomorphic substitutions in the composition of alunogen despite the iron-enriched environment of mineral crystallization. The variability of the alunogen crystal structure is reflected in the number of the “zeolite” H2O molecules and their splitting. The structural complexity of alunogen and its modifications ranges from 333–346 bits/cell for models with non-localized H atoms to 783–828 bits/cell for models with localized H atoms. The higher values correspond to the higher hydration state of alunogen.

Characteristics of geothermal field and evaluation of geothermal resource potential in the Yingjiang Basin

Geothermal resource, a green and sustainable energy resource, plays an important role in achieving ‘emission peak’ and ‘carbon neutrality’ targets. The Yingjiang Basin is located in the eastern branch of the Mediterranean-Himalayan high-temperature geothermal belt and exhibits considerable potential for geothermal resources. However, current investigations into the distribution of deep geothermal resources in this region are somewhat limited. In this paper, the transient plane source (TPS) method is used to measure the thermal conductivity parameters of 31 rock samples within the study area. Additionally, the one-dimensional steady-state heat conduction equation is employed to calculate the deep geothermal field, considering the constraints of rock thermal properties and terrestrial heat flow in the study area. Furthermore, the “stripping method” is used to determine the contribution rate of sedimentary layer to terrestrial heat flow, while the volume method is applied to estimate the geothermal resources at burial depths of 3000–5000 m. The results show that (1) The heat generation rate of granite is the highest with an average value of 4.52 μW/m3, followed by gneiss with an average value in the range of 2.0–3.5 W/(m·K), mudstone and sandstone being the lowest with an average value between 1.0 and 2.0 W/(m·K). (2) The main contributor of terrestrial heat flow in the study area is mantle heat flow, and the contribution of sedimentary layers to terrestrial heat flow only accounts for about 2%. (3) The geothermal resources in Yingjiang Basin within the depth range of 3000–5000 m is 93.6 × 1015 kJ, or 3.2 × 109 tonnes standard coal equivalent (SCE).

Controlling effects of cap rocks on the formation of deep geothermal resources

Cap rocks with high thermal insulation are important for deep geothermal systems at a depth of 3000‒6000 m. Based on the deep geothermal geological conditions in the Fujian-Guangdong-Hainan area of South China, this study established an ideal geological model of reservoir-cap rock assemblages and simulated the geothermal field distribution of cap rocks of different thicknesses and thermal conductivity. The simulation results show that the vertical geothermal temperature distribution in an uplifted area of a depression was present as inverted mirror reflections relative to the elevated area of the basement. Specifically, the isotherms above the elevated area are convex in shape, while those below the elevated area are concave. There is a temperature equilibrium line between the convex and concave isotherms. The heat flow moves from the depressed area to the uplifted area below the temperature equilibrium line and migrates in an opposite direction above the line. On this base, this study conducted the inversion of geothermal temperature fields in typical areas with thin, moderately thick, and thick cap rocks. The results indicate that, at the depth of 3000–6000 m, areas with thin cap rocks (igneous rock zone in the coastal area of Fujian) mainly host moderate- to low-temperature hydrothermal resources; areas with moderately thick cap rocks (Yuezhong Depression) have the geothermal temperature ranging between 100 °C and 200 °C and may develop moderate- to high-temperature hydrothermal resources and hot dry rocks (HDRs), with the former superimposing on the latter; and areas with thick cap rocks (onshore Beibuwan Basin) have a geothermal temperature of 120‒220 °C, and contains mainly moderate- to high-temperature hydrothermal resources and HDRs. Therefore, it is recommended that the evaluation, exploitation, and utilization of deep geothermal resources be carried out according to the burial depth of the temperature equilibrium line and the specific demand for geothermal resources.

Integrated application of gravity, aeromagnetic, and electromagnetic methods in exploring the Ganzi geothermal field, Sichuan Province, China

The Ganzi geothermal field is located in the Songpan-Ganzi orogenic belt in Sichuan Province. Many hot springs are exposed along the Yalahe valley in Ganzi geothermal field, which is a favorable area for high-temperature geothermal resource exploration. However, the geological model of heat exchange, the regional structure controlling hydrothermal convection and the development model of geothermal reservoirs are still unclear. Therefore, further studies are necessary to meet the geothermal exploration requirements in the middle and deep strata of this geothermal field. In this study, a geological model of the geothermal system of Ganzi geothermal field is proposed. We are convinced that there exists a hydrothermal convection system in the Ganzi geothermal field, the heat transfer of which is accomplished through deep-rooted major faults. Therefore, the identification of deep-rooted major faults and the description of geothermal reservoirs are the research objects of the integrated geophysical methods. The main factors controlling the geothermal reservoirs in the deep-rooted Xianshuihe major fault and Yalahe fault zones are analyzed by using gravity, aeromagnetic, and electromagnetic methods and techniques. The analysis results of regional gravity and aeromagnetic anomalies show that the Xianshuihe major fault has produced obvious gravity and aeromagnetic anomalies on the surface, and thus the position and strike of this fault can be accurately predicted by inversion of the aeromagnetic anomalies. Geothermal reservoirs show low-resistivity anomalies in the electromagnetic profile. The inversion results of the controlled source audio-frequency magnetotelluric (CSAMT) data show that geothermal reservoirs are mainly developed along the Yalahe valley, and the west side of the valley is more favorable for geothermal exploration. This study is of guiding significance to the efficient exploitation and utilization of the Ganzi geothermal field.

Anatomy of the convective geothermal system from geophysical and hydrochemical data: A case study from the Changshou geothermal field, South China

There are abundant low-medium temperature geothermal resources in southern China; however, a lack of research into their properties restricts the utilization of the geothermal energy. To expand the geothermal energy potential in southern China, it is vital to clarify the nonvolcanic geothermal system mechanisms. This study aimed to elucidate the mechanisms for the Changshou geothermal field, as a representative structurally controlled convective geothermal system, by analyzing the geophysical and hydrochemical data. The surface-to-subsurface (400 m depth) electrical resistivity structure of the geothermal field was obtained by 2D inversion of two intersecting controlled-source audio-frequency magnetotellurics and electrical resistivity tomography geophysical profiles. We identified the cap rock, reservoir, and fluid pathways of the geothermal system and verified them via drilling results. The cap was composed of Quaternary sediments and Cretaceous sandstone with moderate resistivity (10–50 Ωm), and the geothermal reservoir and fluid pathways were composed of dolomites and fracture zones with low resistivity (less than 5 Ωm), respectively. The hydrochemical results showed that the geothermal water was of the type HCO3·SO4−Ca·Mg, with low values of total dissolved solids resulting from shallow groundwater mixing. Isotope analyses indicated that the geothermal water was derived from precipitation in the Dahong Mountains, southeast of the geothermal field. The average temperature of the geothermal reservoir, as estimated by chalcedony and K-Mg geothermometers, was 53°C. Based on the geothermal gradient calculation, the circulation depth of the groundwater was 1500 m, with the circulation process driven by heat flows originating deep within the earth. The Changshou geothermal field was identified as a potential source of energy for residential heating in winter, owing to the large flow (2700 m3/d) and high permeability (24.03 m/d) of the geothermal reservoir.

Quantitative analysis of naphthalene, 1-naphthol and 2-naphthol at nanomol levels in geothermal fluids using SPE with HPLC

Naphthalene (NAP), 1-naphthol (1-NAP) and 2-naphthol (2-NAP) are the thermal decomposition products of naphthalene sulfonates making them potentially new geothermal reservoir permeability tracers, however, to date, no sensitive and fast detection method for these compounds has been developed. In order to facilitate sensitive and rapid analysis of these compounds in geothermal brines and associated steam condensates, a high-performance liquid chromatography (HPLC) method combined with solid-phase extraction (SPE) has been developed.•A method for determination of naphthalene, 1- and 2-naphthol from brines has been developed.•These compounds have been detected in steam samples from three New Zealand geothermal fields.•As breakdown products of NDS/NSA, these compounds have potential use as geothermal tracers.

Three-dimensional magnetotelluric inversion for the characterization of the Sol de Mañana high-enthalpy geothermal field, Bolivia

We describe the three-dimensional magnetotelluric modeling results of Laguna Colorada - Sol de Mañana geothermal field in SW Bolivia. It is located near Laguna Colorada in the foothills of the Western Cordillera of the Andes and at the margin of the Altiplano-Puna Magma Body (APMB), which is characterized by a vast electrical conductivity anomaly and corresponding seismic anomalies in the mid and deep crust. The magnetotelluric (MT) data comprising 70 stations were modeled by a 3-D inversion. The final model shows a broad conductor at a few hundred meters in depth, which we interpret as the confining cap layer. Beneath, equally widespread, a layer of intermediate resistivity marks the high-temperature hydrothermal reservoir. Detailed interpretation of MT data with information from existing wells suggests a potential for a high-enthalpy geothermal field.

Environmental fate and ecological impact of the potentially toxic elements from the geothermal springs.

Potentially toxic elements from geothermal springs can cause significant pollution of the surrounding environment and pose potential risk to the ecosystem. The fate of potentially toxic elements in the water-soil-plant system in the Yangbajain geothermal field on the Tibetan Plateau, China was investigated to assess their impact on the eco-environment. The concentrations of Be, F, As, and Tl were highly elevated in the headwaters of the Yangbajain geothermal springs, and their concentrations in the local surface water impacted by the geothermal springs reached 8.1μg/L (Be), 23.9mg/L (F), 3.83mg/L (As), and 8.4μg/L (Tl), respectively, far exceeding the corresponding thresholds for surface and drinking water. The absence of As-Fe co-precipitation, undersaturated F-, and weak adsorption on minerals at high geothermal spring pH may be responsible for the As- andF-rich drainage, which caused pollution of local river. As concentrations in the leaves of Orinus thoroldii (Stapf ex Hemsl.) Bor were up to 42.7μg/g (dry weight basis), which is an order of magnitude higher than the allowable limit in animal feeds. The locally farmed yaks are exposed to the excessive amount of F and As with high exposure risk through water-drinking and grass-feeding.

A natural state model in TOUGH2 for the Las Tres Virgenes geothermal field, Baja California Sur, Mexico

The availability of geothermal resources in Baja California has been thoroughly documented in the past. This region currently experiences a deficit in electricity production and it is, to date, disconnected from the National Electric Grid. It is therefore essential to provide strategies for a sustainable production of geothermal electricity in this region that besides, contributes to the increasing need for decarbonization of electricity industry. Here we propose an updated conceptual model of the Las Tres Virgenes hydrothermal system, a currently exploited geothermal area that has been active for more than two decades. The objective of this model is to provide thermal and aquifer relationships that gave rise to this system in its natural state. To achieve this, an updated structural model is presented based on recent geological interpretations of the area. Geochemical and geophysical evidences are also integrated in a conceptual model. A detailed pre-processing step of geological data is incorporated to preserve as much as possible the critical field evidences in the discrete model. Numerical simulations are then conducted using TOUGH2 and the equation of state for water and air (EOS3). As a result, the geothermal field is conceived, and numerically validated, as a fault-hosted fossil aquifer. The upflow that feeds the reservoir interacts with a network of faults. Since the faults hosting the aquifer belong to the regional structural feature of Santa Rosalia Basin, it is imperative to deepen the study of these system with regard to their storativity and permeability since they may control the fate of the system in the long term.

Crust-mantle differentiation and thermal accumulation mechanisms in the north China plain

The North China Plain, which is the central part of the lithospheric thinning in the North China Craton, is rich in clean geothermal energy. However, a current lack of understanding about the thermal accumulation mechanisms of the deep geothermal resources in this area is hindering the exploration, exploitation, and utilization of these resources and the achievement of the carbon reduction targets. Based on deep drilling and the tests of thermal property parameters at different depths, this study calculated the terrestrial heat flow and the heat flux at different depths of the lithosphere in the North China Plain and revealed the lithosphere thermal structure characteristics and the thermal accumulation mechanisms in the plain, obtaining the following results. The North China Plain has widely varying terrestrial heat flow of 33.5–92.1 mW/m2 (average: 62.1 ± 17.04 mW/m2). The average mantle heat flow and crustal heat flow in the plain are 42.05 ± 13.90 mW/m2 and 20 mW/m2, respectively, which account for approximately 67% and 33% of the total surface heat flow in the plain, respectively. This plain has a greatly varying Moho depth of 30–40 km and a Moho temperature of 420–920 °C mostly. The thermal lithosphere in the North China Plain has a thickness of 80–100 km and a thermal structure of the cold crust and hot mantle type. It has thinned on a large scale due to the extensional process, and the mantle-derived materials have migrated upward along the weak structural plane (e.g., deep faults) after pressure release and remelting. The resultant high mantle heat flow serves as a stable heat source for the formation of layered medium-low temperature geothermal fields.

Surface geochemical anomaly pattern of medium-to-high temperature geothermal systems in South China and its application

The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion, volatilization, upward migration, and loss of gas in the strata. As a result, a low-concentration gas field will be formed in the strata above geothermal reservoirs. Geothermal reservoirs could in turn heat formation water and increase the solubility of soluble inorganic salts in the surrounding rocks and the total dissolved solids (TDS) content in the formation water. Since water can strongly wet and permeate strata, the dissolved inorganic salts migrate into upper strata along with water, giving rise to the formation of a high-concentration inorganic salt field in the strata above geothermal reservoirs. A higher geothermal reservoir temperature corresponds to more significant characteristics mentioned above. Therefore, a medium-to-high temperature geothermal system has a surface geochemical anomaly pattern of high inorganic salt concentrations and low gas concentrations (also referred to as the high-salt and low-gas pattern). This pattern is applied to the surface geochemical exploration of the two geothermal fields in Guangdong Province, i.e., the Huangshadong geothermal field in Huizhou City and the Xinzhou geothermal field in Yangjiang City, revealing low-concentration gas fields above both. The application results also show that the exposed thermal spring water in both geological fields has higher concentration of dissolved inorganic salt than the surface water and nearby seawater, forming high-amplitude anomalies on the surface above geothermal reservoirs. These characteristics, as well as the measured temperature at known geothermal wells, verify the validity of the high-salt and low-gas pattern of medium-to-high temperature geothermal systems proposed in this study. Moreover, the high-salt and low-gas pattern proposed predicts three favorable medium-to-high temperature geothermal zones in the surface geochemical exploration of the Shiba Basin near the Huangshadong geothermal field.

Ubiquitous Earthquake Dynamic Triggering in Southern California

AbstractEarthquakes can be dynamically triggered by the passing waves of other distant events. The frequent occurrence of dynamic triggering offers tangible hope in revealing earthquake nucleation processes. However, the physical mechanisms behind earthquake dynamic triggering have remained unclear, and contributions of competing hypotheses are challenging to isolate with individual case studies. To gain a systematic understanding of the spatiotemporal patterns of dynamic triggering, we investigate the phenomenon in southern California from 2008 to 2017. We use the Quake Template Matching catalog and an approach that does not assume an earthquake occurrence distribution. We develop a new set of statistics to examine the significance of seismicity‐rate changes as well as moment‐release changes. Our results show that up to 70% of 1,388 global M ≥ 6 events may have triggered earthquakes in southern California. The triggered seismicity often occurred several hours after the passing seismic waves. The Salton Sea Geothermal Field, San Jacinto fault, and Coso Geothermal Field are particularly prone to triggering. Although adjacent fault segments can be triggered by the same earthquakes, the majority of triggered earthquakes seem to be uncorrelated, suggesting that the process is primarily governed by local conditions. Further, the occurrence of dynamic triggering does not seem to correlate with ground motion (e.g., peak ground velocity) at the triggered sites. These observations indicate that nonlinear processes may have primarily regulated the dynamic triggering cases.

A study on the effects of fault architecture on fluid circulation in the Gediz Graben by the finite volume method

It is widely recognized that in geothermal fields, meteoric water infiltrates deep into the subsurface of the earth and then travels through cracks and fractures, returning to the surface as it becomes heated. The patterns of fluid flow are primarily determined by the interaction between forces driven by gravity and pressure gradients. The ultimate forms of fluid flow patterns are primarily determined by the anisotropies of permeability associated with fault zones. In this study, a series of numerical simulations utilizing the finite volume approach were conducted to investigate the effects of fault zone architecture on fluid flow patterns and temperature distributions. Four distinct types of fault zone architecture were created in the simulations, including localized barrier, combined conduit-barrier, localized conduit, and distributed conduit. The results revealed that fault zone architecture has only a minor effect on fluid flow velocities and temperature distributions, except in cases along faults with very high permeabilities. The simulations suggest that this type of 2-D numerical modeling can be easily applied and utilized in other faulted geothermal systems.

Surface subsidence and uplift resulting from well interventions modeled with coupled analytical solutions: Application to Groningen gas extraction (Netherlands) and CO2-EOR in the Kelly-Snyder oil field (West Texas)

This study presents a novel analytical model for history-matching the observed subsidence and/or uplift due to, respectively, fluid extraction from – or injection into – the pore space of subsurface reservoirs. Development of the model was prompted by the need to have a fast evaluation tool to support the various exploitation modes of subsurface reservoirs, either in fluid extraction projects (hydrocarbons, aquifers, geothermal fields) or in fluid storage projects (waste water, natural gas, hydrogen, and CO2-sequestration). The model proposed here is a novel analytical solution method obtained by coupling the vertical strain changes in a reservoir due to changes in reservoir pressure with a buckling plate model for the overburden. After a brief review of state-of-the-art (numerical and analytical tools), the coupled reservoir pressure change and overburden buckling model (in brief: pressure change-buckling model) is presented. Subsequently, the coupled pressure change-buckling model is applied in two case studies. The first case study history-matches the subsidence of the Groningen Field (Netherlands) over the period 1963–2020, due to the pressure depletion caused by natural gas extraction. The second case study applies the model to history-match the uplift history above an oil field in Scurry County (West Texas) over the period 2007–2011, due to net fluid injection related to enhanced oil recovery (EOR) activities. Separately, in addition to history-matching applications the coupled pressure change-buckling model can also be applied in forward modeling mode to predict the surface response of future operations involving pressure changes in subsurface reservoirs.

Shallow Ground Characterization Of Gedongsongo Geothermal Field Based On Microtremor Data

Shallow Ground Characterization Of Gedongsongo Geothermal Field Based On Microtremor Data

A Review of Critical Element Concentrations in High Enthalpy Geothermal Fluids in New Zealand

This review compiles publicly available datasets describing the chemical composition of geothermal fluids from eight wells in the Taupo Volcanic Zone (TVZ) and Ngāwhā, New Zealand. Our review allows previously reported geothermal reservoir water compositions at various locations around the TVZ (and Ngāwhā) to be assessed and compared for the first time. The combined data present a new perspective on potential critical elements of geothermal resources and will be a valuable tool for future research projects and investment opportunities. Composition data were used to estimate the annual flux of different elements in New Zealand geothermal systems. Several elements found in New Zealand geothermal fluids are currently considered ‘critical’ for the transition to a carbon-neutral economy and are present in economically extractable quantities. We estimate that each year, approximately 1100 tons of lithium pass as heat exchange fluids through Wairakei geothermal power station. An overview of the critical elemental capture and extractive potential from New Zealand’s geothermal fields is provided.

Field investigation on geothermal pavements

This article investigates the thermal response of a geothermal pavements located in Adelaide, South Australia. This geothermal pavement field trial is believed to be the first full-scale instrumented system of its kind in the country, and one of the handful around the world to date providing a rare set of experimental data. The ground temperature and weather parameters were monitored for over two years, including during two thermal response tests (TRTs) undertaken under different weather conditions. The annual ground temperature profile under the pavement provides helpful information for geothermal pavements design and model validation. Results revealed the significant impact of weather conditions on the TRTs due to the shallow burial depth of the pipe heat exchanger. To minimise these effects, it is then recommended to perform TRT or thermal performance testing during mid-season. Comparison of test results showed that the effect of ambient temperature was more intensive in summer due to the presence of heat-absorbing asphalt at the surface. In addition, the high amount of absorbed heat at the surface reduced the pavement depth-temperature fluctuations in winter as well as the temperature difference between days and nights, leading to a better performance.

Effects of different fracture parameters on microseisms induced by hydraulic fracturing

The microseism induced by hydraulic fracturing is of great significance to the development of geothermal reservoirs and the site selection of geothermal systems. In this study, taking geothermal field data from Qiabuqia as a geological reference, several models are developed for hydraulic fracturing simulations based on the models included in the commercial FracMan™ software suit. A series of numerical simulations are carried out to explore the effects of different fracture parameters, including the existence of faults, in-situ stress state, fracture occurrence, and fracture distribution near faults, on the induced microseisms. The results show that during hydraulic fracturing, the existence of faults does affect the propagation direction of the newly generated fractures, causing the fractures to extend toward the fault. The faults also increase the magnitude of microseismic events and make the distribution of microseismic events farther. Under three different in-situ stress states, the magnitudes of induced microseisms and the distance between microseismic events and injection wells are different, mainly due to the different forms of energy release. The total energy of induced microseisms under the reverse faulting stress state (RF) is the largest. Under the normal faulting stress state (NF), the number of microseismic events is the least, with only 28, and these microseismic events are concentrated near the well, with the farthest distribution distance of only 150 m. The fracture occurrence has a significant effect on induced microseisms, mainly affecting the number and distribution range of induced microseisms. With the same number of fractures, as the fracture concentration to the fault increases, both the maximum magnitude and the farthest distribution distance of the induced microseisms increase.

Hydrothermal fluid flow modeling using numerical simulation to identify potential reservoir zones in the Mount Rajabasa geothermal field

The exploration of geothermal resources on Mount Rajabasa is still at an exploratory stage. Various exploration methods and conceptual models have been developed, however, there is no accurate numerical model for hydrothermal fluid movement. In this study, we use numerical simulations to develop a preliminary model of hydrothermal fluid flow to identify the reservoir potential zone in Mount Rajabasa. The numerical simulation method was conducted using the USGS HYDROTHERM code. Input and validation parameters were calculated based on manifestation measurements and previous studies. Results from the study indicate that the geothermal reservoir lies below Mount Rajabasa and Balirang, with dimensions of approximately 4 ​km long and a thickness of 2–2.5 ​km. The water mass flow model also exhibited similarities to field conditions, including fluids at temperatures more than 100 ​°C that appeared in the W. Simpur, G. Botak, W. Merak, and Pangkul manifestation areas in the 40,000th iteration year as a steady-state condition. The mass movement model of the steam reaches 1×10−7g/s.cm2 forming a centered pattern under the peaks of Mount Rajabasa and Balirang with a pattern consistent with the resistivity distribution model of the previous magnetotelluric study. The model predicts a reservoir fluid temperature range of 250–380 ​°C. Furthermore, the model indicates that the reservoir is located between 800 and 1200 ​m below the surface. The model estimates that the reservoir contains a majority of water in the two-phase zone, with a thick layer of cap rock beneath the Rajabasa peak.

Assessment of geothermal potential of Kumaun Himalaya: A perspective for harnessing green energy

Energy is an essential part of human life, and its demand has exponentially increased after the industrial era, especially in developing countries. India has many geothermal springs (GTSs ∼340) in orogenic and non-orogenic belts, but their potential must be better known and utilized as an efficient green energy resource. Therefore, we attempted for the first time to estimate the reservoir temperature of geothermal springs (n = 17) using dissolved silica geothermometry along the Goriganga, Ramganga, and Kali rivers in the Kumaun Himalaya, Uttarakhand. The average and highest reservoir temperatures were 113 °C and 135 °C at Savildhar, respectively. The average reservoir and fluid circulation depths were ∼1.24 km and 1.27 km, respectively. An inverse relationship between reservoir temperatures and the distance of geothermal fields from the Main Central Thrust evinces structural control over the geothermal fields. Most of the studied GTSs (n = 14) have reservoir temperatures between 100 °C and 150 °C, making them medium enthalpy and suitable for Binary Organic Rankine Cycle power plants. Two springs with reservoir temperatures between 70 °C and 100 °C can be used for industrial, space heating, balneotherapy, and other direct uses. Since geothermal power plants do not require any fuel to produce electricity, this study emphasizes on exploiting the geothermal potential of Himalayan geothermal springs.