Comparative Study on Geothermal Potential Exploration Efficiency in the Donetsk and Ruhr Coal Mining Areas

In this study, we compared the closed mines of the Donetsk basin of Ukraine and the Ruhr coal mining area of Germany by the conditions of mine water heat recovery. The set of criteria includes maximum thermal capacity, heat pump COP , the relation of energy gained to energy spent, potential profit of operation, and CO 2 emission reduction. The complex indicator of efficiency that comprises all these parameters was used to rank eight mine drainage stations in Ukraine and the same number in Germany. Based on the calculations for potential open-loop and closed-loop systems, we revealed statistically significant correlations between expected energy efficiency, the water temperature, and the flooding interval length for 27 mines in Ukraine and 28 mines in Germany. The average expected thermal capacity of closed-loop systems at the current water level in the mines of the two basins is similar, against the background of higher heterogeneity of geothermal conditions in Donbas and greater depths and higher temperatures in Ruhr area mines. The similarity of mining conditions and estimated energy efficiency indicators of geothermal systems for two basins is in favor of the feasibility and efficiency of such systems in Ukrainian mining sites.