Geothermal energy in Germany: Revolutionary solution for the energy transition?

Geothermal energy in Germany: Revolutionary solution for the energy transition?

Geothermal energy in Germany is playing an increasingly central role in the energy transition and the desired climate-neutral energy supply. A current research project led by Johannes Gutenberg University Mainz (JGU) is investigating temperature-related rock changes in geothermal reservoirs in order to better understand risks such as earthquakes and increase social acceptance of geothermal projects. The project, called TRIGGER, was started on April 1, 2025 and receives around two million euros in funding from the Federal Ministry for Economic Affairs and Energy, of which around one million euros is earmarked for the JGU groups. Those involved at JGU include experts from various fields such as volcanic seismology, tectonics and structural geology as well as geodynamics and metamorphic processes, which illustrates the comprehensive approach to research. Loud University of Mainz A central aim of the investigations is the analysis of deformations, fluid flows and fracture processes within the rocks.

An important aspect of geothermal energy use are the temperature gradients, which average three degrees per 100 meters in Germany and even reach up to five degrees in the Upper Rhine Graben. The deep geothermal energy projects focus on thermal water reservoirs that are over 1,500 meters deep and can be economically used to generate electricity or heat. Injection temperatures in the Upper Rhine Graben are typically 70 degrees Celsius. The Federal Ministry of Education and Research also supports research to improve the use of deep geothermal energy in order to overcome technical challenges and increase the availability of suitable geological formations, for example in the North German Basin and the Alpine foothills.

Exploration and use of deep geothermal energy

Deep geothermal energy offers the potential to cover up to 25% of Germany's heat needs. Nevertheless, less than 1% of the heat generated from renewable sources in Germany currently comes from deep geothermal sources. To further advance this technology, geophysical methods are needed to locally identify heat sources in the subsurface. How deep geothermal energy works is based on extracting hot water from one well and returning cooled water to another, allowing heat to be efficiently distributed across district heating networks.

The city of Berlin plans to become climate neutral by 2045, and switching its heat supply to renewable energy sources is a crucial part of this strategy. Over 90% of current heat comes from fossil fuels, which urgently needs to change. Geologists estimate that deep geothermal energy could potentially provide up to 20 percent of the heat needed in the metropolitan region. The technology has already proven itself in many German systems and could soon be used as an essential component in local and district heating networks. However, special regional conditions and resources must first be comprehensively examined in order to exploit the full potential Berlin.de notes.

Technical challenges and opportunities

One of the biggest challenges in using deep geothermal energy is the technical and economic risks that inhibit widespread implementation. Induced seismicity is a central topic that is being addressed within the framework of the research projects initiated. Continued investigation of the microstructural and microchemical composition of samples is intended to provide a deeper understanding of geothermal processes, thereby helping to minimize these risks and maximize the efficiency of geothermal energy use. Experts emphasize that this research will also be used to develop tools that optimize the planning, implementation and monitoring of deep geothermal energy projects in order to promote widespread use, such as BMBF reported.

In summary, geothermal energy in Germany could play a crucial role in achieving climate goals, provided appropriate research efforts are continued and the remaining challenges are overcome.