Low-enthalpy Geothermal Energy Potential of Mine Water from Closured Underground Coal Mines in Northern Spain

Abstract

The contribution of renewable energies to the world's total energy demand has increased particularly during the last decades, and they will continue gaining market share. The European energy and climate policies have as one of their targets 20% of final energy from renewable origin by 2020. Underground coal mines closured and flooded constitute large underground reservoirs that can be economically managed to supply geothermal energy (heating and cooling) by means of heat pumps. This paper analyzes the geothermal potential of the water stored inside the coal mines of the Asturian Central Coal Basin (ACCB) and the reduction of CO2 emissions compared to the use of fossil fuels. The results of the study that has been carried out show a capacity of 50 MWt. The potential for generation thermal energy is 112,000 MWh/year with an electric consumption of 14,000 MWh/year. The Coefficient Of Performance (COP) medium is 8 kWht/kWhe. The reduction of CO2 emissions compared to other fuel sources can reach 80%.