While near-surface geothermal energy supplies individual buildings in combination with heat pumps, heat from the deeper subsurface can be fed directly into district heating networks. Deep geothermal energy can thus supply entire neighborhoods with heat. There are 42 deep geothermal energy sites in Germany. A further 100 projects are scheduled to be connected to the grid by 2030. This technology is expected to cover a large part of Germany's heating needs in the future. However, there are a number of hurdles to overcome along the way.
ED: What are your research projects about?
Prof. Michael Drews: Although deep geothermal energy is based on a simple concept, its implementation is complex and requires a broad spectrum of geoscientists and engineers. The Bavarian Geothermal Alliance brings together these skills through collaboration between various disciplines, departments, and universities. My field of work focuses on the potential and optimization of deep geothermal energy, so how we can safely, sustainably, and efficiently use geothermal energy from depths up to six kilometers.
Our research is centered around the subsurface part - the “geo” in geothermal energy. We address tectonics and geomechanics, sedimentology and geophysics, rock physics, and drilling technology: Knowledge of the geological conditions of the subsurface to be developed is immensely important. Where should drilling take place and which rock layers are to be expected? Is there sufficient thermal water underground and will it be available for the entire period of use? Whether a deep geothermal project can be implemented successfully and safely depends crucially on knowledge of the subsurface´s geology.
What challenges do you encounter on your way into the subsurface?
The deep drilling required for geothermal energy is expensive and must be carried out safely and efficiently in order for deep geothermal energy to be competitive. To ensure this, it is essential to have a good understanding of the subsurface when drilling to depths of several kilometers. Our research focuses on mechanical interaction: we try to characterize the subsurface as accurately as possible in terms of the pressures and stresses interacting with the boreholes.
We want to avoid events during drilling, such as unwanted inflows of formation water and gas or borehole instabilities. Understanding of pressure and stress conditions is also key during the production and reinjection of thermal water from and into the subsurface. A lack of understanding of these parameters can lead to artificially generated micro-earthquakes, which in some cases can be felt on the surface.
How high is the risk of an earthquake in Bavaria caused by hydrothermal geothermal energy?
In southern Bavaria, where we use hydrothermal geothermal energy, the risk of noticeable earthquakes is very low - naturally occurring and noticeable seismic activity is practically non-existent in southern Bavaria. Nevertheless, slight but noticeable micro-seismicity has occurred. Although this usually causes no damage, it understandably does not contribute to public acceptance.
What can be done to increase renewable energies?
Every municipality must now submit a plan outlining how it intends to advance its heat supply and become climate neutral. Deep geothermal energy is a real option, especially if a district heating network already exists. The city of Munich is a pioneer in this field and is currently implementing its seventh project to operate the district heating network using deep geothermal energy.
Our contribution to the expansion of geothermal energy is to provide planners, plant operators, and authorities with regional geological context, geoscientific models, and concepts. This enables them to better understand the geothermal system and to implement the development and extraction of geothermal energy safely and efficiently on a local and project-specific basis. To achieve this, we combine techniques from various disciplines, such as drilling technology and geophysics, to minimize risks in energy production from deep geothermal projects and to maximize safety and efficiency.
What methods do you use in your research?
In addition to the data and experience gained from geothermal projects, we have access to hundreds of boreholes and geophysical data from the time of oil and gas production between the 1950s and 1980s. This is a huge amount of data, which we are now evaluating holistically for the first time for our research. The quality and structure of the data play an important role in this. One of our goals is to set new standards and, for example, to establish a global and standardized database for measurements and indicators that tell us something about the pressure conditions in the subsurface.
We also work with international partners, such as the Norwegian state research institute SINTEF, to test the use of artificial intelligence. How can we use AI to automatically minimize drilling risks based on borehole measurements? How can we use AI to make the evaluation of this huge dataset more efficient?
How did the idea to offer the course on citizen participation procedures come about? What would you like to pass on to students?
Students in the Master's program in Geothermics/Geoenergy receive interdisciplinary training in geosciences, mechanical engineering, legal issues, business administration, and citizen participation - a key qualification for providing adequate information and communication on the subject. Together with the University of Applied Sciences Neu-Ulm, I am supervising a doctoral thesis on this topic as part of the BayWiss program, which is why I am very pleased to be offering the course on citizen participation together with them starting this winter semester.
Above all, students should be enabled to understand and anticipate the concerns of the population regarding deep geothermal energy. They should be empowered to communicate facts clearly and in a way that is generally understandable. At information events, citizens express concerns and ask questions that are not necessarily expected from a technical perspective - from a scientific perspective, this form of public engagement therefore always offers a gain in knowledge.
Prof. Drews successfully completed the tenure track process in September 2025. We congratulate Prof. Drews on this well-deserved recognition!
The Bavarian Geothermal Alliance is a joint project funded by the Bavarian State Ministry of Science and the Arts, which was launched in 2016. Under its umbrella, the Ludwig Maximilian University of Munich (LMU), Munich University of Applied Sciences (HM), Friedrich Alexander University of Erlangen-Nuremberg (FAU), University of Bayreuth (UBT), and the Technical University of Munich (TUM) pool their research activities. It brings together the geosciences and engineering sciences and also facilitates knowledge transfer between science, industry, and politics.
FAU and TUM offer a master's degree program in GeoThermics/GeoEnergy, which is partially funded by the Bavarian Geothermal Alliance. Starting in the second semester, classes are held at TUM in Munich on Thursdays and Fridays.