Hydrogeothermal Resources Research Articles

Technologies of the Integrated Development of Hydrogeothermal Resources of the North Caucasian Region

This paper focuses on the technologies of the integrated development of high-parametric geothermal brines with steam release. They differ from each other depending on initial parameters. Such way of brine utilization will make it possible to transform thermal energy to electrical power along with significant increasing its salinity that contributes to chemical components extraction. The opportunity is considered of this technology application in the Tarumovka geothermal field with electric power generation in steam-turbine and binary power plants, and consequent obtaining valuable mineral components. The geothermal and biogas technologies are given proposing integrated utilization of thermal water for various applications. Such systems make it possible to use resource potential of geothermal well and biomass that will result in improvement of economic and environmental situation in the North Caucasus region.

Numerical optimization of geothermal energy extraction from deep karst reservoir in North China

Buildings of more than 34,000,000m2 areas are heated by hydro-geothermal energy in Tianjin, China. Karst reservoir is currently the most important hydro-geothermal resources under utilization. However, the imbalance between production and injection leads to a sharp decline of geothermal pressure. Thus, the geothermal doublet system composed of injection and production wells is required for sustainable production. This study takes Panzhuang karst geothermal reservoir (PGR) as an example, and establishes a regional-scale 3D realistic geothermal model to understand the natural status of temperature distribution in PGR, and the variation of temperatures in both production reservoirs, caprocks and deep wells under exploitation. Furthermore, the well placement is optimized, considering economic cost, to maintain the reservoir pressure and reduce the risk of heat breakthrough. The results show that the injection well should be placed downstream to the production well with a distance of 700 m. The optimized production and injection rates are estimated at 150 m3/h, which is able to maintain the wellhead temperature with the range from 97.5 °C to 99.5 °C, heat extraction rate of 12.4 MW for 50 years and the maximum pressure change in the reservoir below 140 kPa.

Systematic potential analysis on renewable energy centralized co-development at high altitude: A case study in Qinghai-Tibet plateau

In the context of global carbon reduction, many countries have established carbon–neutral commitments. With abundant wind–solar–hydro–geothermal resources, the development of renewable energy in the Qinghai–Tibet Plateau can meet the demand for carbon neutrality. Accordingly, this study aims to carry out an innovative and systematic assessment of renewable energy, considering the new pattern of multiple renewable energies (wind, solar, hydro, and geothermal energy) centralized co-development. A propagable analysis is conducted, based on two hypotheses, namely, considering resource conditions and taking plateau-specific practical constraints and energy storage into account. Resource concentration and synergy are further analyzed by a novel indicator and multiple scenarios are initiated to reduce the subjectivity, while various distance thresholds for substations with varying voltage levels are innovatively defined to optimize the assessment accuracy. Taking the Lhasa River Basin as the study area, results show that areas with suitable resources for two, three, and four types of renewable energy centralized co-development account for 41.3%, 32.7%, and 5.8% of the total area, respectively. After constraints considered, eligible areas for wind, photovoltaic, geothermal, and hydro power decline sharply to 6.0%, 22.3%, 13.5%, and 13.1% of the entire basin, with potentials of 4.91, 12.68, 10.77, and 0.97 GW. Under the highly suitable scenario, the proportions plummet to 0.2%, 1.6%, 0.6%, and 0.4%, with potentials of 0.12, 0.99, 0.29, and 0.02 GW, reflecting a high sensitivity to plateau-specific practical constraints. Wind power potential is the most sensitive to construction difficulty and investment reward among these resources, whereas hydropower potential has the strongest response to ecological protection. Results also show that more than a quarter of the renewable energy centrally developable areas have energy synergies, indicating the applicability of renewable energy centralized co-development.

Development of the Polish geothermal sector in the light of current possibilities of financial support for a geothermal investment

Geothermal energy is an internal heat of the Earth, that is a prospective and sustainable source of renewable energy. In Poland, despite having significant amount of low-temperature geothermal resources, its share in the national energy mix remains marginal but growing. Currently, the utilisation of geothermal resources is related to hydrogeothermal resources, that are used mainly in space heating, recreation and balneotherapy. Nevertheless, the indication of potential electricity production is under research. The utilisation of geothermal resources entails a plenty of environmental benefits that are particularly important in the context of the present pollution problem. Therefore, the development of the geothermal energy sector is of relevant importance and with appropriate legal and financial conditions it may have a bearing on improvement of the environment’s quality and, ipso facto, living in Poland. Thus, this paper presents numerous possibilities of obtaining a financial support for investments in geothermal energy sector. Selected funding and financial backing systems currently available in Poland are discussed. The importance of opportunity of obtaining a financial support for an investment as one of the crucial factors for the geothermal sector development is emphasised. Moreover, the examples of installations implemented in the country in the context of obtained funding are presented.

Perspectives of geothermal water use in the Podhale Basin according to geothermal step distribution

At present, hydro-geothermal resources in which waters in bores are the carrier of heat energy have commercial importance in Poland. Geothermal waters should feature the highest possible temperature in the outflow, low mineral content, high capacity and low deposit depth. Even though geothermal energy is included in renewable sources of energy, complete depletion of the deposit is the largest risk in extracting geothermal waters. This is why these waters should also feature deposit renewability. There are currently several geothermal provinces with beneficial geothermal conditions in Poland, with the area of the Podhale Basin in the Inner Carpathians region being regarded as the most promising. The Podhale deposit also meets all of the above listed conditions. The possibility of using hydrothermal energy in Poland is practically available throughout the country, but operational use of hot groundwater must be profitable for investors. From another point of view, the environmental impact of such investments should be minimized. This paper is concerned with the special variety of temperature of geothermal waters extracted in the area of the Podhale Basin, which is the basic aspect in using deposits of this type.

Technologies for the exploration of highly mineralized geothermal resources

The prospects of the integrated processing of the high-parameter geothermal resources of the East Ciscaucasia of artesian basin (ECAB) with the conversion of their heat energy into electric energy at a binary geoPP and the subsequent extraction of solved chemical compounds from thermal waters are evaluated. The most promising areas for the exploration such resources are overviewed. The integrated exploration of hightemperature hydrogeothermal brines is a new trend in geothermal power engineering, which can make it possible to significantly increase the production volume of hydrogeothermal resources and develop the geothermal field at a higher level with the realization of the energy-efficient advanced technologies. The large-scale exploration of brines can solve the regional problems of energy supply and import substitution and fulfill the need of Russia in food and technical salt and rare elements. The necessity of the primary integrated exploration of the oil-field highly mineralized brines of the South Sukhokumskii group of gas–oil wells of Northern Dagestan was shown in view of the exacerbated environmental problems. Currently, the oil-field brines with the radioactive background exceeding the allowable levels are discharged at disposal fields. The technological solutions for their deactivation and integrated exploration are proposed. The realization of the proposed technological solutions provides 300 t of lithium carbonate, 1650 t of caustic magnesite powder, 27300 t of chemically precipitated chalk, 116100 t of food salt, and up to 1.4 mln m3 of desalinated water from oil-field brines yearly. Desalinated water at the output of a geotechnological complex can be used for different economic needs, which is important for the arid North Caucasus region, where the fresh water deficiency is acute, especially in its plain part within the ECAB.

Environmental aspects of the geothermal energy utilisation in Poland

Geothermal energy is considered as a strategic and sustainable source of renewable energy that can be effectively managed in several economic sectors. In Poland, despite the abundant potential of such resources, its share in the energy mix of renewable energy sources remains insubstantial. The utilisation of geothermal resources in Poland is related to the hydrogeothermal resources, however, numerous researches related to petrogeothermal energy resources are being performed. The utilisation of each type of energy, including geothermal, has an impact on the natural environment. In case of the effective development of geothermal energy resources, many environmental benefits are pointed out. The primary one is the extraction of clean, green energy that is characterised by the zero-emission rate of pollutants into the atmosphere, what considering the current environmental pollution in many Polish cities remains the extremely important issue. On the other hand, the utilisation of geothermal energy might influence the natural environment negatively. Beginning from the phase of drilling, which strongly interferes with the local landscape or acoustic climate, to the stage of energy exploitation. It should be noted that the efficient and sustainable use of geothermal energy resources is closely linked with the current law regulations at national and European level.

A Structural-Thermal Model of the Karkonosze Pluton (Sudetes Mountains, SW Poland) for Hot Dry Rock (HDR) Geothermal Use

Abstract The main objective of this study was to develop a spatial temperature distribution of the Karkonosze Pluton to indicate optimum locations for HDR systems at drillable depth. HDR geothermal technology makes it possible to extract heat from the Earth in areas where no hydro-geothermal resources are present. To produce electricity in a binary cycle, system temperatures of > 100°C are usually required. In this paper, the authors have analysed the potential opportunities for applying HDR technology in the area of the Karkonosze Pluton, which is regarded as an optimum location for the application of the HDR concept (due to the potential for stimulation offered by the mechanical properties of the granites, radiogenic heat production, modern tectonic activity, and the thickness of the pluton). The model used in the analysis, which takes into account a hypothetical assessment of the manner and paths of fluid migration within the pluton, provides an insight into the spatial distribution of subsurface temperatures. It thus allows the location of relatively shallow high-temperature zones, which are optimal for the efficient application of HDR technology, to be identified. With respect to this technology, the Szklarska Poręba area and the NE part of the pluton seem to be better targets than the Cieplice central area, where the model indicated much lower temperatures (e.g. at a depth of 5,000 m, estimated temperatures in the vicinity of Szklarska Poręba were about 185°C and in the vicinity of Cieplice they were about 140°C).

INTEGRATED EXPLORATION OF GEOTHERMAL RESOURCES

The aim. The aim is to develop the energy efficient technologies to explore hydro geothermal resources of different energy potential. Methods. Evaluation of the effectiveness of the proposed technologies has been carried out with the use of physical and mathematical, thermodynamic and optimization methods of calculation and the physical and chemical experimental research. Results. We propose the technology of integrated exploration of low-grade geothermal resources with the application of heat and water resource potential on various purposes. We also argue for the possibility of effective exploration of geothermal resources by building a binary geothermal power plant using idle oil and gas wells. We prove the prospect of geothermal steam and gas technologies enabling highly efficient use of thermal water of low energy potential (80 - 100 ° C degrees) to generate electricity; the prospects of complex processing of high-temperature geothermal brine of Tarumovsky field. Thermal energy is utilized in a binary geothermal power plant in the supercritical Rankine cycle operating with a low-boiling agent. The low temperature spent brine from the geothermal power plant with is supplied to the chemical plant, where the main chemical components are extracted - lithium carbonate, magnesium burning, calcium carbonate and sodium chloride. Next, the waste water is used for various water management objectives. Electricity generated in the binary geothermal power plant is used for the extraction of chemical components. Conclusions. Implementation of the proposed technologies will facilitate the most efficient development of hydro geothermal resources of the North Caucasus region. Integrated exploration of the Tarumovsky field resources will fully meet Russian demand for lithium carbonate and sodium chloride.

Geothermal energy and its application opportunities in Serbia

Geothermal energy is accumulated heat in the fluid and rock masses in the Earth 's crust. The natural decay of radioactive elements (uranium, thorium and potassium) in rocks produces heat energy. The simplest use of geothermal energy for heating is by heat pump. Geothermal energy can be used for production of electricity. It uses hot water and steam from the earth to run the generator. Serbia has significant potential for geothermal energy. Development of geothermal resources till 2015. will replace at least 500.000 tons of imported liquid fuels per year. The total amount of accumulated heat in geothermal resources in a depth of 3 km is two times higher than the equivalent thermal energy that could be obtained by burning all types of coal from all their sites in Serbia! The total abundance of geothermal resources in Serbia is 4000 l/s. Abundance of wells in Vojvodina is 10-20 l/s, and the temperature is from 40 to 60°C. Exploitation of thermal waters in Macva will cause heating of following cities: Bogatic, Sabac, Sremska Mitrovica and Loznica, with a total population of 150.000 people. The richest hydrogeothermal resources are in Macva, Vranje and Josanicka Banja. Using heat pumps, geothermal water can be exploited on the entire territory of Serbia! Although large producer, Serbia is importing food, i. e., fruits and vegetables. With the construction of 100-150 ha of greenhouses which will be heated with geothermal energy, Serbia will become an exporting country.

PROSPECTS OF GEOTHERMAL RESOURCES DEVELOPMENT FOR EAST CISCAUCASIA

Abstract . Work subject. Aim. The Northern Caucasus is one of the prospective regions for development of geothermal energy.The hydrogeothermal resources of the only East Ciscaucasian Artesian basin are estimated up to 10000 MW of heat and 1000 MW of electric power. For their large-scale development it is necessary to built wells of big diameter and high flow rate involving huge capital investments. Reconstruction of idle wells for production of thermal water will allow to reduce capital investments for building of geothermal power installations. In the East Ciscaucasian Artesian basin there are a lot of promising areas with idle wells which can be converted for production of thermal water. The purpose of work is substantiation possibility of efficient development of geothermal resources of the Northern Caucasus region using idle oil and gas wells. Methods. The schematic diagram is submitted for binary geothermal power plant (GPP) with use of idle gas-oil wells where the primary heat carrier in a loop of geothermal circulation system is used for heating and evaporation of the low-boiling working agent circulating in a secondary contour of steam-power unit. Calculations are carried out for selection of the optimum parameters of geothermal circulation system for obtaining the maximum useful power of GPP. The thermodynamic analysis of low-boiling working agents is made. Development of medial enthalpy thermal waters in the combined geothermal-steam-gas power installations is offered where exhaust gases of gas-turbine installation are used for evaporation and overheat of the working agent circulating in a contour of GPP. Heating of the working agent in GPP up to the temperature of evaporation is carried out by thermal water. Results. The possibility of efficient development of geothermal resources of the Northern Caucasus region by construction of binary geothermal power plants using idle oil and gas wells is substantiated. The capacities and the basic characteristics of GPP in the promising fields are considered. Prospectivity of geothermal and steam-gas technologies is showed which allow using the low enthalpy thermal waters (80–100 оС) for electrical energy generation. Conclusions. 1. One of the ways of efficient involvement of geothermal resources in a power balance of the region is construction of the binary GPP using a fund of idle oil and gas wells. The capital expenditure for their reconstruction for production of thermal water is much lower than costs of construction of new wells. At the same time use of idle wells doesn't allow to receive big capacities on GPP because of restriction of a circulating flow rate because of small diameters of wells. Construction of binary GPP on existing wells will enhance energy security and reliability of power supply of socially important objects, will improve an ecological situation by replacement of organic fuel and will increase a share of renewable energy in a regional power balance. 2. Building of geothermal and steam-gas units will allow using the middle enthalpy thermal water for electric power generation, achieving the deeper temperature drop of thermal water that is important for improvement of the economic parameters of geothermal production and most effectively utilizing the heat of the gas-turbine exhaust gas.

Up-to-date state and prospects for the development of geothermal resources of the North Caucasus region

The modern state of production and use of geothermal resources of the region is evaluated and the low efficiency of their development is shown. Promising developmental technologies of hydrogeothermal resources of various energy potentials with attachment to concrete geothermal deposits are presented. Technologies on the complex development of hydrogeothermal resources with the use of water for drinking or industrial water supply, the thermal potential for various energy needs, and the extraction of the gas and mineral components dissolved in water are highly efficient technologies, which make it possible to solve important environmental, economical, and social problems of the region.

Geothermal energy and its application opportunities in Serbia

Geothermal energy is accumulated heat in the fluid and rock masses in the Earth 's crust. The natural decay of radioactive elements (uranium, thorium and potassium) in rocks produces heat energy. The simplest use of geothermal energy for heating is by heat pump. Geothermal energy can be used for production of electricity. It uses hot water and steam from the earth to run the generator. Serbia has significant potential for geothermal energy. Development of geothermal resources till 2015. will replace at least 500.000 tons of imported liquid fuels per year. The total amount of accumulated heat in geothermal resources in a depth of 3 km is two times higher than the equivalent thermal energy that could be obtained by burning all types of coal from all their sites in Serbia! The total abundance of geothermal resources in Serbia is 4000 l/s. Abundance of wells in Vojvodina is 10-20 l/s, and the temperature is from 40 to 60°C. Exploitation of thermal waters in Mačva will cause heating of following cities: Bogatić, Šabac, Sremska Mitrovica and Loznica, with a total population of 150.000 people. The richest hydrogeothermal resources are in Mačva, Vranje and Jošanička Banja. Using heat pumps, geothermal water can be exploited on the entire territory of Serbia! Although large producer, Serbia is importing food, i. e., fruits and vegetables. With the construction of 100-150 ha of greenhouses which will be heated with geothermal energy, Serbia will become an exporting country.

Hydrogeothermal resources of Middle Lithuania

The main geothermal prospects are related to West Lithuania, while the potential of Middle Lithuania was little considered before. The Cambrian sandstone reservoir was identified as a potential hydrothermal resource in Middle Lithuania. Other large-scale geothermal aquifers have too low temperatures. The study indicates that the effective thickness of the Cambrian geothermal aquifer of Middle Lithuania ranges within 15–58 m, the average porosity of sandstones is 13–20% and permeability averages 370 mD; therefore, these sandstones are classified as a good reservoir. The geothermal potential was calculated for geothermal well doublet. The productivity of the geothermal well doublet is estimated to be as high as 53–175 m 3 /h in the southern part of the study area, while reaching only 16–43 m 3 /h in the north. Accordingly, the geothermal energy production of the well doublet varies from 0.44 MWh to 1.37 MWh in the northern area, ranging from 1.69 MWh to 6.02 MWh in the south. The water of the Cambrian formation is of the NaCl type with a high salinity (98–130 g/l). The thermochemical modelling indicates that depending on water composition, either the precipitation of gypsum or carbonates and hydroxides should be expected in the geothermal system, while other major mineral phases remain unsaturated in the geothermal loop. Analysis of the available geothermal resources and their comparison with the heat energy needs of Middle Lithuanian customers indicate that one or two doublet installations exploiting the Cambrian geothermal aquifer may cover the basic needs in the central heating of towns in the region. It is concluded that the Cambrian geothermal aquifer is highly promising for district heating in Middle Lithuania.

Hydrogeothermal resources in spa areas of Serbia: Main properties and possible improvement of use

Geological complexity of the territory of Serbia is a world curiosity: six main geo-tectonic regions and tens sub-regions are delineated in a small area of 88,000 km2. Geologic origin and regional structure of some areas has long been the subject of discussion. Notable magmatism and associated tectonic events in the Earth's crust provided for a fairly large hydrogeothermal resource potential, which is manifested in more than 250 warm (mainly mineral) springs and more than 100 hydrothermal wells. Thermal springs and wells together discharge some 5 m3/s. This potential is used in part for balneal therapy (waters differ in temperature and chemical composition) in the spa areas of Serbia. The amounts of thermal water unused therapeutically or the amounts of heat energy from unused geo-thermal water may be used in almost all spas for space heating/cooling and thus increase the efficiency of the thermal water energy utilization. This also will be cost-effective, reduce emission of noxious gases, and improve the environmental-health image of the resorts. The hydrogeothermal resources are described for 29 spas with 700 l/s total discharge capacity of water temperature between 25?C and 96?C, or an overall heat energy of 78.40 MWt. Feasibility of additional energy utilization of thermal water in spas is generally considered.

Mineral waters and hydrogeothermal resources in Bulgaria

Thermal mineral waters and extractable geothermal energy are an important and still underestimated natural wealth of Bulgaria. Their diversity is due to the complex geological structure, intense neotectonic activity, and the resulting complex character of meteoric water circulation. Reproductive hydrogeothermal systems with low-mineralized thermal waters of meteoric origin and resrvoir temperatures ranging between 30 and 100 (maximum 120) °C occur in the southern and north-eastern part of the country. Their total reproductive potential is estimated at 14–15 m3s−1. In the northern part (Moesian platform), regional hydrogeothermal reservoir with connate (marine) and mixed (marine and meteoric) mineral waters and brines are identified, the temperatures varying from 40 to 140 (maximum 150) °C. Huge resources of geothermal energy with commercial importance are accumulated in them. The hydrogeothermal wealth of Bulgaria provides as important basis for the development of balneological and multi-seasonal tourism, bottling industries, geothermal heating of buildings and greenhouses, aquaculture and other related activities.

Thermomineral waters and hydrogeothermal resources in the western part of the Chalkidiki Peninsula (Northern Greece)

The geologic conditions in the western part of the Chalkidiki Peninsula are favourable for the formation, reproduction and accumulation of six to seven types of mineral waters, and of considerable resources of low-enthalpy geothermal energy and endogeneous CO2. Low-mineralized thermal waters with nitrogen gas composition and comparatively low (25-45°C) temperatures form small accumulations related to fault structures in ophiolitic bodies and metamorphic rocks in the NW of the peninsula. Within the other, bigger part of the peninsula, deposits and regional reservoirs of carbonated (saturated in endogenous CO2) mineral waters with bicarbonate (HCO3), bicarbonate-chloride (HCO3-Cl) or chloride (Cl) composition have been formed. The total mineralisation of these waters increase from 2-5 to 30-40 g/l in function of the depth of the reservoirs, and the temperature increase is from 20-30° to 80-90°, correspondingly. The principal reservoir of carbonated mineral waters and geothermal resources is a considerably tectonised formation of Upper Jurassic limestones which has been buried under Neogene marine sediments at depth from 200-300 to 2000-3000 m. The study and prospects for development of Chalkidiki centers of multiseasonal and curative tourism and a parallel industrial exploitation of geothermal energy and natural CO2.