Seasonal heat storage has been studied in Germany for over 30 years, but to date only a few pilot plant facilities have been built, such as those for borehole geothermal energy storage, pit storage or aquifer storage. A promising yet underutilized approach is the use of abandoned, groundwater-flooded mines for thermal energy storage. These offer high storage capacities due to their large volumes and extensive contact surfaces...

As a renewable energy source, geothermal mine water systems utilize abandoned mines for heating and cooling and contribute to the reduction of CO 2 emissions. There are five different systems for mine water heat recovery, including both open and closed types. A comprehensive review of geothermal mine water systems worldwide, both planned and existing, as well as their accompanying studies, shows that such systems have already...