We research the utilisation of the upper crust for geothermal energy and storage systems. This includes (i) providing quality-controlled data, innovative methods and the development of technologies to utilise the subsurface as part of a sustainable, environmentally sound energy supply. We focus on investigating new heating or cooling concepts from hydrothermal and petrothermal heat sources and developing options for the geological storage of large quantities (TWh) of surplus heat and energy carriers. The main purpose of our work in the Geoenergy Section is the exploration and development of deep reservoirs for energy utilisation. We combine laboratory studies on rock physics (including geomechanics, hydraulics and thermics) and fluid physics as well as fluid-rock interaction under simulated in-situ conditions with investigations in the field and in underground laboratories and combine the obtained data and findings in geological, geochemical, hydraulic, mechanical, thermal and coupled models. From the measured and modelled data, we derive concepts for the safe and efficient use of geological reservoirs and storage formations.