Decommissioned open-pit mines are potential geothermal sources of heating or cooling for nearby population centres

In the shift to cleaner technologies, coal thermal power plants and mines will be decommissioned earlier than planned. These open-pit coal mines show potential as a geothermal source/sink for space heating and cooling, yet this post-closure use option remains unexplored. Here, we assess the techno-economic feasibility of providing heating and cooling using a decommissioned mine pit as a source or sink of heat for nearby population centres. Mixed integer quadratically constrained programming is employed for operational optimisation. The results show that thermal provisioning, considering centralised and decentralised arrangements, is economically competitive under specific scenarios regarding commodities prices, thermal demands and pit source temperature. Notably, a higher pit temperature reduces the overall thermal provisioning costs for residential thermal demands. Improvements in the economics due to transmission pipeline insulation are limited. While an expected decline in the system lifecycle costs occurs for decreasing electricity prices, the results highlight that the relative economic competitiveness of the thermal systems is tied to the individual alternatives’ performance at the same commodities prices. Overall, this paper identifies general conditions for techno-economic competitiveness for the implementation of shallow geothermal systems in the context of mine closure.

Mauricio Carcamo-Medel, Raul Fuentes, Guillermo Narsilio