Groundwater Potential for the Utilisation of Shallow Geothermal Energy from a Closed Coal Mine

Abstract

In accordance with the programme of closure works and the implementation of ecological spatial rehabilitation in the area of the Slovenian coal mine Trbovlje–Hrastnik (RTH), there is a great opportunity to exploit shallow geothermal energy from water and ground sources. In the RTH area, there is great energy potential in the utilisation of underground water and heat from the earth. In our research, we have focussed on the use of geothermal energy with heat pumps from groundwater (water/water system) and from ground collectors and wells up to a depth of 150 m (rock/water system). With the water/water system, we have an average of 2.7 MW of thermal energy available, with the rock/water system having 7.5 kW of thermal energy from a 150 m deep well. With the rock/water system in particular, the development of an industrial zone in the RTH area can also provide for a greater demand for thermal energy. The thermal energy obtained in this way is utilised via heat pumps to heat and cool commercial, residential and industrial buildings. The utilisation of shallow geothermal energy can make a major contribution to carbon neutrality, as the use of geothermal energy has no negative impact on the environment and causes no greenhouse gas emissions. The aim of the paper is to provide an overview of the methods used to analyse heat storage in aquifers of abandoned coal mines, to represent these storages in RTH with a basic mathematical–statistical inventory of what is happening in the aquifer, and to investigate the possibility of using shallow geothermal energy with the help of modelling the use of shallow geothermal energy. The results and analyses obtained can make an important scientific contribution to the use of geothermal energy from abandoned and closed mines.