Our Storage & Underground Systems business area, with its Competence Centres "Mining Exploitation", "Near-Surface Geothermal Energy", "Deep Geothermal Energy and Borehole Systems" and "Storage for Materials and Heat", develops innovative solutions for underground and surface extraction and storage systems and their coupling to local to municipal supply infrastructures. Even after the end of the fossil energy age, underground space will continue to be of special importance for the extraction and storage of thermal energy and energy raw materials. The underground remains a central element of future networked energy infrastructures. This includes large-scale thermal phase change storage as well as material storage for hydrogen, carbon dioxide or natural gas. Our research activities address special applications for the heating and cooling supply of industry and agriculture, such as the reuse of deep boreholes, disused mining infrastructures of opencast mines and of underground mines as well as mine waters. Our services include research-oriented site analyses and feasibility studies for energy technology applications between thermal geophysics and thermal building physics or industrial process control for large near-surface geothermal plants. To this end, we use thermal response tests (TRT) or enhanced geothermal response tests (EGRT), among other methods, to assess the fundamental suitability, design and economic viability of planned geothermal plants. Based on site factors and building characteristics, concepts for heating and/or cooling are created.