Feasibility analysis of using mine water from abandoned coal mines in Spain for heating and cooling of buildings

Abstract

In 2017, renewable energy accounted for 19.5% of the total energy used for heating and cooling in the European Union. This paper analyses the technical and economic feasibility of using mine water from flooded underground coal mines in Spain to provide renewable thermal energy to buildings located in surrounding areas. High efficiency heat pump system is proposed to provide sustainable energy for district heating and cooling, leading to a reduction of greenhouse gas emissions to the atmosphere. The results obtained show that 20 MW of thermal energy is available for heat recovery from mine waters, compared to 4 MW of electrical power committed for pumping from inside the mines and heat pump consumption. The economic model that has been developed indicates that the feasibility of the geothermal plants depends on the amount of thermal energy demanded, the efficiency of the system and the distance from the abandoned mines to potential users. A mine water geothermal plant with 10 MW of power provides energy for about 1,700 households at a distance of 2 km with an investment cost of 3.25 MV. Regarding the reduction of CO 2 emissions, the emission factor is reduced to 0.048 kgCO 2 kWh À1 using this approach.

Geomechanische Auswirkungen saisonaler Wärmespeicherung in stillgelegten Bergwerken

“…From a thermal point of view, the mine heat storage is not effective in this particular layout. In general however, mine heat storage is feasible as demonstrated in Spain [24].…”

Environmental Changes Produced by Household Consumption

“…In addition, the Draft Law on Climate Change and Energy Transition [29] commits Spain to base its electricity system on renewable sources. As such, taking advantage of abandoned mining concessions for the generation of heat from within the earth (geothermal energy) to heat and cool surrounding buildings is envisaged, as has been demonstrated by various studies [30,31].…”

The Value of a Hole in Coal: Assessment of Seasonal Thermal Energy Storage and Recovery in Flooded Coal Mines

“…At present, increasing the exploitation of shallow low-enthalpy geothermal resources is being considered among other alternatives, such as green hydrogen and solar heating applications (Dodds and Demoullin, 2013;Dahash et al, 2019), to reduce the carbon intensity in combination with district heating networks (Sayegh et al, 2017). However, the exploitation of geothermal resources in large-scale open-loop schemes requires a considerable groundwater flow (Bertermann et al, 2015) and the proximity of the heat resource to the potential users (Menéndez et al, 2020).…”