Energy from closed mines: Underground energy storage and geothermal applications

In the current energy transition, there is a growing global market for innovative ways to generate clean energy. Storage technologies are potential and flexible solutions to deal with the intermittent nature of renewable resources. Closed mines can be used for the implementation of plants of energy generation with low environmental impact. This paper explores the use of abandoned mines for Underground Pumped Hydroelectric Energy Storage (UPHES), Compressed Air Energy Storage (CAES) plants and geothermal applications. A case study is presented in which the three uses are combined in just one mine. This preliminary study allows estimating an electrical energy generation of 153 and 197 GWH year(-1) at the UPHES and CAES systems, respectively, and a thermal energy generation of 0.41 GWh year(-1) at the geothermal system, with a total cost of 358 M(sic). An underground closed mine can be used to store energy for re-use and also for geothermal energy generation, providing competitive renewable energy with a low CO2 footprint. These initiatives aid to ensure sustainable economic development of communities after mine closure.