Half of municipal heating is to come from climate-neutral sources by 2030. Deep geothermal energy can make a major contribution to this goal of the German government because it provides a constant supply of local energy regardless of the weather and takes up little space in residential areas.
A joint roadmap by institutions of the Helmholtz Association, including the Karlsruhe Institute of Technology (KIT), and the Fraunhofer-Gesellschaft shows that deep geothermal energy has a market potential in Germany that opens up expansion targets of more than a quarter of Germany's annual heat demand (over 300 TWh). The paper makes recommendations for action to achieve this goal - clear expansion targets, large-scale geological exploration, investment in key technologies and the development of skilled workers are needed.
The heating sector accounts for 56% of the national energy demand. Only 15 % of heat is renewable. The roadmap now presented discusses the contribution of geothermal energy to the heating transition. The focus is on hydrothermal reservoirs, i.e. thermal water-bearing rocks at depths of between 400 meters and 5,000 meters. Geothermal water can be extracted at temperatures between 15 and 180 °C from such deep wells. They are available regardless of the season and time of day and can be used in particular for local and district heating and even for low-temperature processes in industry. The technology is mature and has been used for decades in many European cities, such as Paris and Munich.
According to the estimates in the roadmap, hydrothermal geothermal energy - combined with large heat pumps - as a heat source for district heating networks could cover around a quarter of Germany's total heat demand, theoretically around 300 terawatt hours of annual energy with 70 gigawatts of installed capacity. For comparison: in 2020, 42 plants nationwide supplied 359 megawatts of installed heat output and 45 megawatts of electrical output.
