Mine Water as an Energy Source: Overview of Technical Basics, Existing Plants, and Monitoring Results

Abstract 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 been installed as heating and cooling applications at more than 51 sites. Approximately 85 MW of heating and 20 MW of cooling capacity worldwide are currently provided by geothermal mine water systems, and due to rising energy prices, new systems are increasingly being planned and installed. Most systems have supplied single properties with heating and cooling capacities below 200 KW; however, a trend towards larger systems that are able to provide energy for entire neighborhoods or districts can be observed. In this study, a comparison of monitoring results of four locations in Europe and North America shows that the parallel use of mine water for heating and cooling can achieve seasonal performance factors (SPF) of up to 10 for the overall system. Thus, even with high electricity prices, operational costs for geothermal mine water energy of between 5 and 10 ct/kWh heat are possible. Therefore, depending on fossil energy prices, performance factors of over 3 (Europe) or over 3.5 (USA) are feasible.