Geothermal Energy Potential Research Articles

The DGE-ROLLOUT project: Deep Geothermal Energy potential of Carboniferous carbonate rocks in North-West Europe ‒ History, characterisation, modelling and exploration

The DGE-ROLLOUT project: Deep Geothermal Energy potential of Carboniferous carbonate rocks in North-West Europe ‒ History, characterisation, modelling and exploration

Deep geothermal energy potential at Weisweiler, Germany: Exploring subsurface mid-Palaeozoic carbonate reservoir rocks

Deep geothermal energy potential at Weisweiler, Germany: Exploring subsurface mid-Palaeozoic carbonate reservoir rocks

Prospects and Challenges of Geothermal Energy in Uganda

This paper explores geothermal energy use as a renewable energy option in Uganda. It is discussed in pursuit of sustainable development. Uganda has been undergoing fast economic growth particularly as demonstrated by its resilience against the effects of COVID-19, it must develop its renewable energy resources to match this growth. In this paper, we present the findings of an exploratory research to ascertain potential of geothermal energy for Uganda of 1500MW (3.6% of overall energy potential). The prospects and challenges of geothermal energy development are discussed. In concluding remarks good policies with strong political will, manpower training, financial support for research, and financial and subsidy incentive programs.

Heat Flow Distribution and Thermal Mechanism Analysis of the Gonghe Basin based on Gravity and Magnetic Methods

AbstractGeothermal resource is indispensable as a clean, renewable, stable and cheap resource. Nowadays in China, the Gonghe Basin, located in northeastern Qinghai Province, has been thought to be a promising geothermal area. To explore geothermal energy potential in and around the Gonghe Basin, geophysical means including magnetic and gravity methods were used to plot distribution. Firstly, we inversed Moho depth and Curie point depth in and around the basin using gravity and magnetic data, respectively, through an improved Parker–Oldenburg algorithm. Secondly, seven different thermal models were established, considering radiogenic heat, basement depth, anomalous heat source and simulated corresponding temperature field and heat flow. These were analyzed numerically and we found the high heat flow in the Gonghe Basin co‐acted with radiogenic heat, an anomalous heat source and conductive heat. The distribution of seismic activities indicates that the Langshan–Wuwei–Gonghe Fault might have provided channels for transporting heat effectively.

Gas geochemistry analysis in Candradimuka Crater, Mount Lawu, Central Java, Indonesia

Mount Lawu is a stratovolcano in Central Java that holds a large geothermal energy potential. Within Mount Lawu Geothermal Area, several thermal manifestations could be located one of them being Candradimuka Crater located at the proximity of Mount Lawu peak. This study aims to assess the gas geochemistry in Candradimuka Crater by obtaining gas sample within the crater area. Gas geochemistry analysis uses geothermometer, geoindicator, and N2-He-Ar ternary diagram to analyse the subsurface condition. The analysis reveals that the fluid circulating in the crater originated from meteoric water and that Mount Lawu reservoir temperature ranged between 250°C - 289°C. Based on geological observation and gas geochemistry, Candradimuka Crater is located within the upflow zone of Mount Lawu.

Review of the Heat Flow Mapping in Polish Sedimentary Basin across Different Tectonic Terrains

Heat flow patterns variability related to the age of the consolidated, and differences in, sedimentary thickness of the sedimentary succession are important constraints upon the thermal state of the sedimentary fill and its geothermal energy potential. Heat flow in the Permian basin of central Europe varies from a low of 40 mWm−2 in the Precambrian Platform to 80 mWm−2 in the Paleozoic basement platform influencing temperature for geothermal potential drilling depth. Continuity of thermal patterns and compatibility of heat flow Q across the Permian basin across the Polish–German basin was known from heat flow data ever since the first heat flow map of Europe in 1979. Both Polish and German heat flow determinations used lab-measured thermal conductivity on cores. This is not the case for the recent heat flow map of Poland published in 2009 widely referenced in Polish geological literature. Significant differences in heat flow magnitude exist between many historical heat flow maps of Poland over the 1970s–1990s and recent 21st century patterns. We find that the differences in heat flow values of some 20–30 mWm−2 in Western Poland exist between heat flow maps using thermal conductivity models using well log interpreted mineral and porosity content and assigned world averages of rock and fluid thermal conductivity versus those measured on cores. These differences in heat flow are discussed in the context of resulting mantle heat flow and the Lithosphere-Asthenosphere Boundary depth modelled differences and possible overestimates of deep thermal conditions for enhanced geothermal energy prospects in Poland.

Evaluation of the Shallow Geothermal Potential for Heating and Cooling and Its Integration in the Socioeconomic Environment: A Case Study in the Region of Murcia, Spain

In order to boost the use of shallow geothermal energy, reliable and sound information concerning its potential must be provided to the public and energy decision-makers, among others. To this end, we developed a GIS-based methodology that allowed us to estimate the resource, energy, economic and environmental potential of shallow geothermal energy at a regional scale. Our method focuses on closed-loop borehole heat exchanger systems, which are by far the systems that are most utilized for heating and cooling purposes, and whose energy demands are similar throughout the year in the study area applied. The resource was assessed based on the thermal properties from the surface to a depth of 100 m, considering the water saturation grade of the materials. Additionally, climate and building characteristics data were also used as the main input. The G.POT method was used for assessing the annual shallow geothermal resource and for the specific heat extraction (sHe) rate estimation for both heating and, for the first time, for cooling. The method was applied to the Region of Murcia (Spain) and thematic maps were created with the outputting results. They offer insight toward the thermal energy that can be extracted for both heating and cooling in (MWh/year) and (W/m); the technical potential, making a distinction over the climate zones in the region; the cost of the possible ground source heat pump (GSHP) installation, associated payback period and the cost of producing the shallow geothermal energy; and, finally, the GHG emissions savings derived from its usage. The model also output the specific heat extraction rates, which are compared to those from the VDI 4640, which prove to be slightly higher than the previous one.

Geothermal energy resources in Ethiopia: Status review and insights from hydrochemistry of surface and groundwaters

AbstractEthiopia has an estimated >10,000 MW of geothermal energy potential, more than double its current power generating capacity (4,400 MW). Electricity access stands at 44% of the total population, with 31% in rural areas, so effective development of this low‐carbon resource could make a significant impact to equitable delivery of electricity. However, geothermal energy exploitation must be done responsibly to protect valuable water resources under stress from climate‐change driven drought conditions and competing uses across agricultural, domestic, and industrial sectors. Our review provides progress updates on geothermal developments—which soon aim to deliver more than 1,000 MW of electricity—and performs a high‐level assessment of hydrochemical data for ground and surface waters across Ethiopia. A water quality database was built using publicly available information and three quality control criteria: well‐defined sample location, cation‐anion balance (CAB) of ±10%, and clear fluid type definition. Ethiopia hosts two major geothermal water types, sodium‐alkalinity dominated in the Main Ethiopian Rift and sodium‐chloride dominated in the Afar Depression, separated by sodium‐mixed waters between Dofan‐Fantale and Meteka. H and O stable isotopes suggest a largely meteoric source for geothermal waters, with δ18O enrichment adding to evidence of a high enthalpy resource at Tendaho. Hydrochemical investigations provide critical information for successful delivery of sustainable geothermal energy developments. However, the current lack of data available for Ethiopia poses a significant challenge for completion of predevelopment baselines and ongoing environmental impact assessment. We encourage the release of unpublished findings from private companies and government agencies to build upon our database and demonstrate social and environmental responsibility in the development of Ethiopian geothermal resources.This article is categorized under: Engineering Water > Methods

Oilfield geothermal resources of the Upper Assam Petroliferous Basin, NE India

Extracting geothermal energy from the oil-producing fields is an experimental venture globally. The exploitation and utilization of geothermal energy can partly reduce the larger dependence on conventional non-renewable energy sources like oil, gas, coal, and other fossil fuels, and has a bright prospect. The Upper Assam Basin is a mature petroliferous basin of NE India, where there are several hundred low production, high water cut, or abandoned oil and gas wells that can be retrofitted as geothermal wells instead of drilling new ones. This will help bridge the gap of growing energy demand and limited supply in energy-deficient state like Assam. Situated away from the active plate boundaries and in lack of active volcanism, the Upper Assam Basin remains a low-to-medium enthalpy geothermal fluid regime. The deeper reservoir in this regard can, therefore, be the best candidate for the introspection of the potential geothermal energy reservoir reconnaissance. The selection of a deeper horizon considered in the present case has been the stratified reservoirs of the Lakadong-Therria (Lk-Th) Formation, Sylhet Group of the Lower Eocene age occurring at a variable depth of 3400 m–4600 m. The Lk-Th Formation possesses a fair-quality reservoir with lateral continuity and favourable petrophysical properties. In this study, representative gamma-ray (GR) and resistivity (R) logs were examined to work out lithology, and bed boundary demarcation, etc. The total Formation thickness varies from 97 to 157 m; the individual sand body thickness is up to 6 m. Other reservoir parameters, e.g., porosity (Φ = 8–33 %), water saturation (Sw = 4.57–95.15 %), geothermal gradient (2.71 °C/100m to 3.92 °C/100 m at 4300 m and 3608 m) respectively, and theoretical estimate of high heat flux in the range 70–100 mW/m2/s, are the necessary yard-stick to measure the subsurface geothermal reserves. Efficient energy extraction will have the potential in facilitating energy utilization for industrial purposes, especially in tea processing units present nearby oilfields and also for power generation by the binary mechanism.

Crustal architecture, heat transfer modes and geothermal energy potentials of the Algerian Triassic provinces

The Triassic province is located within the Eastern Algerian Sahara, towards the Eastern edge of the M'zab Dorsal. Several hydrothermal reservoirs have been identified within this area along the Oued Righ valley and Rehabi-Berriane structural axis, forming an area of high temperature geothermal activity. The genetic mechanism of this geothermal system is currently unclear and needs urgent scientific reaction. In this work, we present a new conceptual model of the geothermal system in the Triassic provinces, using the structural model obtained through integrated study of recent edge detection techniques and the calculation of thermal proprieties of the middle and the lower crust. This multidisciplinary approach proposes a novel heat transfer mechanism and reservoir architecture within the province. We used spectral analysis on aeromagnetic data to determine the Curie point depth, geothermal gradient, heat flow, and radiogenic heat production. The results outlined the major structural trends within the Eastern Algerian Sahara. Deep heat flow sources were observed between 12.5 to 23 km depths and the geothermal gradient within the lower crust reaches 35 °C/km. The measurement of the thermal properties in petroleum wells indicates different thermal distributions. The delineated geothermal pattern is linked to the deformation of the Moho and the presence of deep-seated faults along the middle and lower crustal boundary. The shallow Curie point depth can be interpreted to be a result of the crustal thinning giving the high heat flow values. These results provide a physical representation of the heat transfer modes in the Oued Righ and constitute a unique continuous geothermal system within the eastern Algerian Sahara.

2D Forward Modeling Geothermal System Gravity Data in South Solok Region, West Sumatra

Indonesia has the greatest potential for geothermal energy in the world. Geothermal has an important role as an alternative fuel because it is a renewable energy source, but its use has not been maximized. One of the areas that have the greatest potential for geothermal energy in South Solok, West Sumatra. Therefore, this study was conducted to determine the geothermal system in the South Solok area, West Sumatra by using the gravity method. The gravity data processing stage requires some software to get the CBA value(Complete Bouguer Anomaly), map contours of the CBA. Anomaly separation with the butterworth filter method, determination of residual anomaly slice points, and 2D modeling of geothermal systems. Based on modeling, the qualitative interpretation interprets the Complete Bouguer Anomaly map which is suspected as a geothermal prospect area is a low anomaly ranging from 7.9 mgal - 9.4 mgal which is marked in dark blue. Meanwhile, quantitative interpretation produces modeling of the AB and CD slicing with a total of four layers. This layer consists of clay rock as a cap rock, sandstone as a reservoir, granite as a heated rock as a heat source, and the last layer in the form of magma as a heat source. The anomaly modeling of these two sections is dominated by granite rock with a density value of 2500 kg/m3 for the AB section and 2550 kg/m3 for the CD section.

Potential of geothermal energy in the onshore sedimentary basins of Uruguay

In Uruguay, current geothermal energy applications are restricted to recreational and balneology uses of the low-temperature Guaraní Aquifer System (Norte Basin). By integrating geological and geophysical data, we characterized three potential geothermal systems, one in each onshore sedimentary basin. In the Norte Basin, an intermediate-temperature geothermal system (> 95°C) is associated with deep aquifers (~3,500 m) in undrilled structural lows. The thermal waters could be used for a variety of indirect and direct applications. In the Santa Lucía and Laguna Merín basins, low-temperature geothermal systems (~50°C) are proposed, associated with reservoirs at depths of more than 1,000 m.

Evaluation of shallow geothermal energy resources in the Beijing-Tianjin-Hebei Plain based on land use

To discover the characteristics, distribution and potential of shallow geothermal energy in the Beijing-Tianjin-Hebei Plain area. This paper, based on a large amount of data collection and field investigations, evaluateed the shallow-layer geothermal energy in the study area through the analytic hierarchy process and comprehensive index method. Based on suitability zoning results superimposed with 1:100000 land use data, the study area is divided into encouraged, controlled, restricted and prospective mining areas regarding the development of shallow geothermal energy, and the economic availability of shallow geothermal energy in the encouraged and controlled areas are evaluated. The results show that the shallow geothermal energy in the Beijing-Tianjin-Hebei Plain can meet the heating and cooling demand of 6×108 m2 of buildings, equivalent to 1.15×107 t of standard coal, thus reducing carbon dioxide emissions by 2.73×107 t and reducing sulfur dioxide emissions by 1.95×105 t. According to the development and utilization mode, the energy demand level and the Beijing-Tianjin-Hebei coordinated development plan, the development and utilization of geothermal resources in the plain area has two types: Urban concentrated mining areas and rural scattered mining areas. The scale and level of intensive utilization of regional geothermal resources are of great significance.

Exploration of Shallow Geothermal Energy Aquifers by Using Electrical Resistivity Survey in Laki Range Jamshoro district Sindh, Pakistan

Geothermal water is increasingly used around the world for its exploitation. Bulk electrical resistivity differences can bring significant information on variation of subsurface geothermal aquifer characteristics. The electrical resistivity survey was carried out in Laki range in lower Indus basin in the study area to explore the subsurface geothermal aquifers. The Schlumberger electrode configuration with range from 2 m to 220 m depth was applied. Three prominent locations of hot springs were selected including Laki Shah Saddar, Lalbagh and Kai hot spring near Sehwan city. After processing resistivity image data, two hot water geothermal aquifers were delineated at Laki Shah Sadder hot springs. The depth of first aquifer was 56 m and its thickness 38 m in the limestones. The depth of second aquifer of 190 m and with thickness of 96 m hosted in limestone. In Lalbagh hot springs two geothermal aquifers were delineated on the basis of apparent resistivity contrast, the depth of first aquifer zone in sandstone was in sandstone 15 m and thickness 12 m, while the depth of second aquifer was 61m and thickness was 35m. In Kai hot springs two hot water geothermal aquifers were delineated. The depth of first geothermal aquifer was 21m and thickness was 18 m and the depth of second aquifer was 105 m and thickness was 61m present in sandstone lithology. Present work demonstrates the capability of electrical resistivity images to study the potential of geothermal energy in shallow aquifers. These outcomes could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems.

Large-Scale Geothermal Collector Systems for 5th Generation District Heating and Cooling Networks

Low temperature district heating and cooling networks (5GDHC) in combination with very shallow geothermal energy potentials enable the complete renewable heating and cooling supply of settlements up to entire city districts. With the help of 5GDHC, heating and cooling can be distributed at a low temperature level with almost no distribution losses and made useable to consumers via decentralized heat pumps (HP). Numerous renewable heat sources, from wastewater heat exchangers and low-temperature industrial waste heat to borehole heat exchangers and large-scale geothermal collector systems (LSC), can be used for these networks. The use of large-scale geothermal collector systems also offers the opportunity to shift heating and cooling loads seasonally, contributing to flexibility in the heating network. In addition, the soil can be cooled below freezing point due to the strong regeneration caused by the solar irradiation. Multilayer geothermal collector systems can be used to deliberately generate excessive cooling of individual areas in order to provide cooling energy for residential buildings, office complexes or industrial applications. Planning these systems requires expertise and understanding regarding the interaction of these technologies in the overall system. This paper provides a summary of experience in planning 5GDHC with large-scale geothermal collector systems as well as other renewable heat sources.

The Use of Geothermal Energy to Heating Crops under Cover: A Case Study of Poland

Among the many different applications of geothermal energy, its use for agricultural production purposes is noteworthy. The use of geothermal water in greenhouse cultivation is the most modern form of production; it enables the implementation of the production cycle throughout the year while reducing energy costs. In this paper, based on basic heat transfer relations, the heat demand of modern greenhouse constructions was determined. The monthly and year-round heat demand was determined for facilities with diversified heights of the side walls. Depending on the type of unit of greenhouse area analysed (1 ha), the calculated annual heat demand ranged from 11.05 to 12.46 TJ. Based on data on the geothermal energy potential in Poland, investment costs and payback periods were determined for the analysed locations. The locations of the facilities were selected based on traditions of plant cultivation in the greenhouse facilities and the availability of geothermal energy. The analysis showed that, under the adopted conditions, without additional co-financing, and in one of the considered locations, the investment will result in positive financial effects after 15 years. In the case of co-financing, at the level of currently existing values, all locations—irrespective of the assumed period of exploitation—showed satisfactory financial effects.

Upgrading a District Heating System by Means of the Integration of Modular Heat Pumps, Geothermal Waters, and PVs for Resilient and Sustainable Urban Energy

Krakow has an extensive district heating network, which is approximately 900 km long. It is the second largest city in terms of the number of inhabitants in Poland, resulting in a high demand for energy—for both heating and cooling. The district heating of the city is based on coal. The paper presents the conception of using the available renewable sources to integrate them into the city’s heating system, increasing the flexibility of the system and its decentralization. An innovative solution of the use of hybrid, modular heat pumps with power dependent on the needs of customers in a given location and combining them with geothermal waters and photovoltaics is presented. The potential of deep geothermal waters is based on two reservoirs built of carbonate rocks, namely Devonian and Upper Jurassic, which mainly consist of dolomite and limestone. The theoretical potential of water intake equal to the nominal heating capacity of a geothermal installation is estimated at 3.3 and 2.0 MW, respectively. Shallow geothermal energy potential varies within the city, reflecting the complex geological structure of the city. Apart from typical borehole heat exchangers (BHEs), the shallower water levels may represent a significant potential source for both heating and cooling by means of water heat pumps. For the heating network, it has been proposed to use modular heat pumps with hybrid sources, which will allow for the flexible development of the network in places previously unavailable or unprofitable. In the case of balancing production and demand, a photovoltaic installation can be an effective and sufficient source of electricity that will cover the annual electricity demand generated by the heat pump installation, when it is used for both heating and cooling. The alternating demand of facilities for heating and cooling energy, caused by changes in the seasons, suggests potential for using seasonal cold and heat storage.

The evaluation of geothermal energy potential by swot analysis: the case of Aydin

Enerji, dünyada sadece ekonomik kalkınmanın değil, sosyal ve kültürel gelişmenin, buna bağlı olarak da büyüme ve kalkınmanın en temel girdileri arasındadır. Türkiye de baş döndürücü bir hızla artan teknolojiye ayak uydurma çabaları ve hızlı nüfus artışının körüklediği enerji talebiyle, enerjiye yatırımınıöncelikli yatırım kalemleri arasına alan ülkeler arasındadır. Petrol, doğalgaz başta olmak üzere birincil enerji kaynakları açısından dışa bağımlı olan ve bu kaynaklarda yaşanan fiyat dalgalanmalarının olumsuz etkilerine maruz kalan Türkiye, topraklarındaki zengin enerji kaynaklarını ortaya çıkarma mecburiyetiyle karşı karşıyadır. “Milli Enerji ve Maden Politikası”nı benimseyen Türkiye, yatırımlarına hız vermekte ve özellikle yenilenebilir enerji alanında çalışmalarını kesintisiz sürdürmektedir.Çalışmada, Türkiye’nin yenilenebilir kaynaklardanjeotermalin, Aydın ili örneklemesi ile SWOT analizi yapılmış, jeotermalin enerji sektörü açısından güçlü ve zayıf yönleri ortaya konulmuş, olası fırsatlar vetehditler analiz edilerek kazanım ve olası kayıplar tartışmaya açılmıştır. Analiz için geniş bir literatür çalışması yapılmış, konu ile ilgili sivil toplum kuruluşları, üreticiler, kamu ve özel sektör temsilcilerinin görüşleri irdelenmiş ve TÜİK, T.C. Enerji ve Tabi Kaynaklar Bakanlığı, MTA, TMMBO, IRENA, JESDER verilerinden yararlanılmıştır. Çalışmanın amacı, jeotermalin genelde Türkiye, özelde Aydın ili için önemini ortaya koymak, Aydın ili için taşıdığı risk ve kazanımlara işaret etmek ve konuya tüm paydaşların dikkatini çekerek gerekliçalışmaların yapılmasına katkı sağlamaktır.

Renewable energy sources potential evaluation in Romania

Renewable energy sources (wind energy, solar energy, energy hydropower, ocean energy, geothermal energy, biomass and biofuels) are alternatives to conventional fuels in the greenhouse gases emissions reduction process. Because of the EU legislation support, the renewable energy sources have evolved significantly in recent years and in 2009 EU set a target of 20% energy consumption comes from renewable energy sources by 2020. In 2018, the target has been set for 32% of energy consumption from renewable energy sources by 2030. There is currently a debate on the policy framework future for the period after 2030. Greenhouse gas emissions is considered a serious threat regarding climate change, with potentially disastrous effects on humanity. The use renewable energy sources (RES), together with improved energy efficiency, can contribute to the reduction of energy consumption, the reduction of greenhouse gas emissions and, consequently, to prevent dangerous climate change. The potential of biomass, solar, hydro, wind and geothermal energy is very important, especially in recent years, due to financial support mechanisms such as green certificates, which in many European countries helped this sector to developed progressively.

Sustainable Modularity Approach to Facilities Development Based on Geothermal Energy Potential

The study presented in this paper assessed the multidisciplinary approach of geothermal potential in the area of the most southeastern part of the Pannonian basin, focused on resources utilization. This study aims to present a method for the cascade use of geothermal energy as a source of thermal energy for space heating and cooling and as a resource for balneological purposes. Two particular sites were selected—one in a natural environment; the other within a small settlement. Geothermal resources come from different types of reservoirs having different temperatures and chemical compositions. At the first site, a geothermal spring with a temperature of 20.5 °C is considered for heat pump utilization, while at the second site, a geothermal well with a temperature of 54 °C is suitable for direct use. The calculated thermal power, which can be obtained from geothermal energy is in the range of 300 to 950 kW. The development concept was proposed with an architectural design to enable sustainable energy efficient development of wellness and spa/medical facilities that can be supported by local authorities. The resulting energy heating needs for different scenarios were 16–105 kW, which can be met in full by the use of geothermal energy.