In Sava, Drava and Slavonia-Srijem depression there is average temperature gradient of around 50°C/km and vertical conductive heat flow of around 75 mW/m2 (Jelić et al., 1995), which as the geothermal energy source is studied within the meaning of the heat transfer source, circulating (injecting, then producing) instead of producing heat transmission fluid. That concept, known as the enhanced geothermal system (EGS) or hot dry rock has several prerequisites – high grade metamorphic rock that contains 15 times more geothermal energy than sedimentary rock, temperature sufficient for a cost-effective conversion to electricity and low investment prediction in the meaning of building the facilities and extensive research and analyses. CO2, which is observed as the alternative heat transmission fluid to the water is attractive because EGS is expected to be accompanied with injected fluid loss, i.e. a part of the injected fluid will be trapped in the formation. Taking into account that carbon dioxide is greenhouse gas and that its reduced emission can be profitable for countries that are part of EU ETS CO2 market there is one more factor that reduces cost of the CO2 EGS. Lithological data from the oil and gas wells in Sava depression were examined for preliminary estimate of possible EGS reservoirs and estimate of electricity production as a function of temperature and inflow rate of heat transmission fluid, i.e. water and CO2 is done

Rudarstvo, nafta i geološko inženjerstvo