Geological and economical prospectives of developing geothermal energy in Ukraine

Abstract

Purpose. To solve the problem, the objective of the paper has been formulated as follows: to perform comprehensive technical and economic assessment of the efficiency of geothermal resources development at various depths within the zones with the increased values of heat flow in the earth’s crust. The methodology. The analysis of the zones of the earth's crust, which have elevated geothermal gradient values with the selection and hydrogeological description of potential for the use of thermal aquifers located within the Transcarpathian Downfold, Volhynia-Podilia Plate, Dnieper-Donets Depressionwas carried out. The economic, hydro and thermodynamic calculations of the possibility of their development are carried out. Findings.. Taking into account the determined significant mineralization of the thermal water, geotechnical scheme of its environmentally safe use has been substantiated; the scheme suggests water pumping onto the surface, heat extraction, and water pumpback into the bed. The proposed circulation system is characterized by the increased energy balance since it helps extract almost all the heat of ground water as well as a certain share of the heat from the enclosing rocks. To evaluate the efficiency of the technique under different conditions, a mathematical model has been developed to determine changes in the temperature of water during its circulation, power costs for that process, and thermal efficiency of the module. The originality. The considered geocirculation system, which involves thermal water pumping onto the surface, heat extraction from the water, and water pumpback into the bed, solves a problem of its utilization and increases considerable the percentage of geothermal energy recovery at the expense of its combined intake both from the ground water and water-bearing rocks. Practical implications.. The studies have allowed evaluating economic efficiency of the development of geothermal resources in Ukraine and determining net present value of geocirculation system depending upon the depth of reservoir geothermal gradient, and water consumption.