Use of closured open pit and underground coal mines for energy generation: Application to the Asturias Central Coal Basin (Spain)

Abstract

The idea to reducing the dependency of nuclear and fossil energy sources has risen in Spain, then, the use of closured coal mines for energy generation is thus in the political interest, and by 2020 it is intended that the country produces 20% of its energy from renewable sources, therefore replacing the energy based on fossil fuels. New studies on the framework of a circular economy have led to found new possibilities for closured coal mines in historical mine districts and mine water can be considered as a potential resource, converting mining exploitations into storage and production facilities of renewable energy and generating new economic activities in the mining regions. Abandoned and flooded mines constitute artificial karst type aquifers, and these created underground reservoirs can be economically managed to supply geothermal energy to villages around the shafts. This potential application of mine water, profitable in both economic and environmental terms, could contribute to improve economic and social conditions of traditional mining areas in gradual decline. On the other hand, the restored lands can be used for the production of biofuels through repopulation with fast-growing energy crops and high planting densities. This paper analyses the uses of mine water for energy generation both as geothermal resource and through pumped storage between an underground and a surface reservoir, furthermore the supply of productive restoration for biomass production in closured coal open pits is considered, in relation to their potential application to the closured coal mines from the Asturias Central Coal basin in Northern Spain.