GEOECOLOGICAL ASPECTS OF GEOTHERMAL POWER ENGINEERING 

S. V. Cherkasov^1,*, A. M. Farkhutdinov², I. M. Farkhutdinov¹

¹Vernadsky State Geological Museum RAS, ul. Mokhovaya 11, bld. 11, Moscow, 125009 Russia
²Bashkir State University, ul. Zaki Validi, 32, Ufa, 450076 Russia
^*E-mail: s.cherkasov@sgm.ru 

Geoecological aspects of geothermal power engineering are related to the existing technologies in using the Earth's heat. It is both the direct use (the use of hot groundwater for heat production, i.e., hydrothermal systems), and the production of electricity (enhanced  geothermal systems, EGS, as well as geothermal systems based on natural steam-water mixtures, i.e., petro- and hydrothermal systems, respectively).  The advantages of using geothermal resources in relation to other energy sources are considered in geoecological respect. Geoecological risks associated with the operation of geothermal natural and man-made systems are considered. These risks are related to possible chemical contamination resulting from the mineralized groundwater spills on the surface, with technological change in hydrodynamic equilibrium, with the depletion of the reservoir and lowering the temperature of underground waters caused by reinjection of the cooled heat-transfer fluid. These risks could be minimized by full reinjection of the used fluid, monitoring of heat-transfer fluid leaks, microseismic activity monitoring in the area of operation of petrothermal resources, predicting negative processes using computer mathematical modeling methods, and optimizing circulation systems for heat extraction.The experience of minimizing geoecological risks by the example of the Khankala experimental industrial geothermal station is considered in the article. The advantage of hydrothermal natural and technogenic systems over petrothermal ones at the current level of development of drilling and heat extraction technologies is proved proceeding from the qualitative analysis of geoecological risks and existing heat extraction technologies. It is determined that the deposits of geothermal water with full reinjection of the used fluid is the most environmentally friendly renewable energy source that does not depend on weather conditions. At the same time, it is noted that the technologies created for hydrothermal natural and human-made systems form the basis for both improving the efficiency of hydrothermal and petrothermal energy development.  

Keywords: geoecological risks, geothermal groundwater, geothermal resources, hydrothermal systems, renewable energy

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