The demand for heat generation based on renewable energies has become increasingly important during the last decades, especially
in urban areas. Geothermal energy, the heat stored in the upper part of the Earth?s crust, offers a huge but largely untapped
potential. Specifically, the use of near-surface geothermal energy increased significantly in Germany. Medium and deep geothermal
energy systems provide a wide range of applications for environmentally friendly, large scale heat provision. Aquifer Thermal Energy
Storage (ATES) systems, for example, offer great potential for heat supply in major cities (Fig. below, left). A case study, led by GFZ,
investigated the potential of an ATES system in the centre of Berlin. The research well Gt BCh 1/2015 on the campus of the Technical
University of Berlin was established, geologically characterized, and hydraulically tested.
Deep geothermal systems play another important role within the future energy supply. In hydrothermal systems, direct use or conversion
of extracted heat to electricity can be obtained at economically feasible costs (Fig. below, right). These resources, however,
are limited in most countries due to local geological conditions. Nonetheless, sufficient heat in place is encountered in other geological
settings such as the so called ?petrothermal? systems, which could cover the heat demand for centuries. However, the initial productivity
of these systems is often too low for an economically viable utilization. Further research and demonstrators are needed to
improve the efficiency and sustainability of geothermal energy systems. Gro? Sch?nebeck, the geothermal research site of the GFZ,
has been established as a research platform for technology development and process understanding in order to achieve a broader
spectrum of technical solutions for using this domestic form of energy.