In the future, heat or electricity could be extracted from the earth's interior using thermal water at around 150 geothermal plants in Germany (Landkarte "Tiefe Geothermieprojekte in Deutschland", Bundesverband Geothermie e.V., 2025). In order to access the hot water, an injection well and a production well are required, which must be planned and implemented individually depending on the composition of the thermal water and the properties of the reservoir. Researchers at TU Bergakademie Freiberg are now developing an open source software that simulates the entire process during operation for a specific location. This enables geothermal plants to drill and produce electricity and/or heat without disruption.
"In order to operate a geothermal power or heating plant without disruptions, one is mainly interested in how much of the thermal water naturally present underground arrives at the above-ground power plant with what temperature, chemical composition and physical properties during extraction," says project manager Professor Moh'd Amro. According to the geothermal fluid mechanics expert of TU Bergakademie Freiberg, these factors can be controlled primarily by continuously monitoring the pressure, temperature, pH value and flow rate: "These factors are of fundamental importance for regulating the effects on the geomechanics of the near-borehole area as well as precipitation and corrosion in the borehole, as they determine the flow of hot water through the earth's interior to the heating plant. If these factors are well coordinated, the water runs smoothly and maintenance-related downtimes of the plant are reduced under optimal conditions."
Making simulation available for geothermal plants
Numerical simulations are already being used for the planning of the borehole as well as for the operation of the plants. For the first time, the Freiberg team's new software will calculate the optimum conditions both for the flow of hot thermal water to the heating plant through the borehole and for the subsequent injection of cold water in the second borehole in order to avoid unwanted downtimes. "The calculations not only take into account the temperature and pressure of the water flow, but also other factors such as geomechanics, precipitation and possible sand production in the area close to the borehole." The team draws the calculation basis for the new software from published operating data of geothermal plants as well as geothermal research projects from Germany and around the world.
The prototype of the software is expected to be tested in use at several geothermal plants in the coming year and will ultimately be made available to all interested users as free open source software. "We want to provide operators of geothermal plants with a tool that will help them to better monitor, understand and control the drilling process from the reservoir to the surface," says Amro. "Thanks to the feedback from the application, we can take into account the experiences of the individual geothermal regions in Germany in the research project and thus generate a proactive transfer of knowledge and best practices for future projects."
With the newly approved deep geothermal energy project, which was initiated in collaboration with my colleague Dr Hakan Alkan, my team here at the university wants to raise awareness of deep geothermal energy, which is still underestimated, and thus make an active research contribution to the implementation of the ambitious energy transition! My professorship has thus completed the transformation of research activities from fossil fuels to deep geothermal energy, but also to issues of large-scale underground storage of green hydrogen and the topic of underground storage of carbon dioxide.
Prof. Moh'd Amro
About the WellFrei research project
The research project "Borehole flow simulator for geothermal energy production under consideration of different borehole and reservoir conditions" (WellFrei) has been funded since 1 September 2025 with a total of 302,000 euros over a project duration of two years. The Chair of Geostreaming, Production and Storage Technology at the Institute of Drilling Technology and Fluid Mining at TUBAF is the sole applicant and processor of the project. The acronym WellFrei stands for the deep geothermal borehole ('well') and Frei for the university town of Freiberg. The professorship's other research projects on deep geothermal energy include the joint project agEnS to optimise the drilling path in a geothermal reservoir in the Upper Rhine Graben and the research project GeBoLop, which is dedicated to increasing the service life of borehole shaft pumps in extremely hot reservoirs.
Background: Function of a power plant for hydrothermal geothermal energy
To supply heat with the help of geothermal heating plants, thermal water from depths of over 400 metres is used. Geothermal power generation requires water with temperatures of over 120 degrees Celsius, which is typically tapped at depths of around 2,000 - 4,000 metres. The hot thermal water is brought to the surface via a production well, where it circulates in a closed circuit. Through a heat exchanger, it transfers its heat to a heat transfer medium, which drives turbines (in a second circuit) to generate electricity. Heat can also be extracted and utilised as district heating. The cooled thermal water is then channelled back underground via an injection well. (Source: German Geothermal Energy Association)
Further information
- WellFrei FKZ 03EE4074 Funding is provided by the Federal Ministry for Economic Affairs and Energy (BMWE).
- Collaborative project "Demonstration of an adaptive, multilateral reservoir exploration for geothermal energy for seismicity and cost mitigation in the Upper Rhine Graben" agEnS
- Collaborative project "Closed lubricant circuit for geothermal borehole shaft pumps; sub-project: Development and testing of an innovative lubricant recirculation system for borehole shaft pumps in geothermal energy" GeBoLop
Master's programme in geothermal energy prepares students for the energy source of the future
