Dialogue

Rimbach’s mayor, Holger Schmitt, described the information event as an important component for transparency and public information, particularly with regard to the upcoming next phase of the project. “We in politics and administration in Rimbach and the surrounding municipalities are following developments with great interest and will continue to contribute with a critical perspective,” Schmitt said in his welcoming remarks.

In the technical presentation section of the event, GeoLaB project leader Dr. Bastian Rudolph from Karlsruhe Institute of Technology provided an overview of the importance of geothermal energy and the objectives of the research project. The planned underground rock laboratory is intended to enable the investigation of geothermal reservoir technologies under realistic yet controlled conditions. The findings are expected to be transferable to suitable sites throughout Europe. Rudolph also explained the next steps after the Tromm region was deemed suitable for GeoLaB research at the end of April. “To prepare for the approval process, we are planning further drilling operations and geophysical investigations. We are also searching for a suitable entrance for the tunnel. In doing so, we aim to keep impacts on people and nature during the construction phase as low as possible,” Rudolph explained. He also explicitly addressed the planned dimensions of the GeoLaB underground laboratory, noting that the tunnel is currently being planned with a length of one to two kilometers and a diameter of approximately six meters.

Following this, hydrogeologist Christoph Schüth from TU Darmstadt explained that data relating to water resources around the Tromm area have already been collected for the past two years through an extensive monitoring network. According to Schüth, this large-scale monitoring effort is complemented by long-term data from public authorities and is being continuously expanded by the GeoLaB team. Over time, this will create a solid basis for the approval process and allow potential impacts to be identified at an early stage.

Following the presentations, numerous visitors took the opportunity to ask questions and continue discussions directly with the experts. The concluding information market allowed participants to gain deeper insights at several themed stations — including the GeoLaB project and its dialogue initiatives, the geology of the Tromm region, water-related topics, and the digital twin used to visualize research data — and to engage directly with the scientists.

The event is part of an ongoing dialogue process with the public that will continue throughout the further planning stages.

On Sunday, October 12, 2025, the GeoLaB team participated in the Rimbacher Herbst, just as in the previous year. Visitors took the opportunity to engage in in-depth conversations with us about geothermal energy in general, about the GeoLaB project in particular, and to ask their questions. We thank everyone for their interest and the stimulating exchange!

We also brought along experiments on different types of rocks and their water permeability. Those who wanted to dive deeper into the topic could talk with Prof. Schüth and Dr. Horovitz from TU Darmstadt. Both are experts in hydrogeology and are currently studying the groundwater resources in the Tromm region for the GeoLaB project.

The GeoLaB project once again offered the opportunity to look over the shoulders of scientists at their research work. This time, the GFZ German Research Centre for Geosciences in Potsdam, one of the project partners in the GeoLaB research network, invited visitors to the Tromm.

At the beginning of September, GFZ carried out the second seismic survey campaign within the GeoLaB project. This time, the signals were also recorded from the borehole, providing an even more detailed picture of the Tromm. Anyone interested in this topic could visit an information booth at the nature playground on September 6, 2025, to talk with scientists and learn more about seismics.

The GeoLaB team invited the public to an open-air information market at the drilling site on the Tromm. On Sunday, June 29, 2025, GeoLaB staff provided information about the project. From 2 to 5 p.m., interested visitors could drop by without registration and learn about the project, geology, and the drilling activities at various booths — all under sunny and blue skies.

Around 180 people visited the construction site on these two days. At three different times (10:45 a.m., 12:00 p.m., and 1:15 p.m.), groups were guided onto the site and received information from members of the GeoLaB team about the geology of the Odenwald, the drilling process, the planned scientific investigations, and their significance for the GeoLaB project. Visitors came with many questions. On March 8, they were even able to watch as a granite core (10 cm in diameter) was pulled from the borehole.

For safety reasons, the number of participants had to be limited, and attendance was only possible with prior registration. The tours proved very popular and were fully booked quickly.

Many citizens once again took the opportunity to get answers to their questions in personal conversations: Why is the laboratory currently being planned in the Odenwald? How long will the preparatory survey campaigns on the Tromm last? Can we benefit from the investigations? Why is the BGE (Federal Company for Radioactive Waste Disposal) involved in this project?

By the way, you can also find the answers to these and other questions here on our website in the FAQ section.

We sincerely thank all visitors for their questions and the lively conversations!

“We don’t just want to explain our research in theory — we want people to experience it,” explained Katharina Schätzler, head of communications for the GeoLaB project, describing the idea behind the excursion. The group of participants approached the truck on foot, stopping at several stations along the way. Only at the final stop, directly at the parking area next to the truck, were the vibrations noticeable. The measuring devices brought along also showed no signal before that point.

In addition to answering many general questions about the project and the exploration activities now beginning, the scientists provided insights into the world of rocks with small experiments. This, too, sparked great interest among the participants.

This was especially well received by the children. Adults took the opportunity to learn more about the project in the Odenwald and get answers to their questions: Why is the laboratory currently being planned in the Odenwald? How long will the survey campaign on the Tromm last? Can we benefit from the investigations? Why is the BGE (Federal Company for Radioactive Waste Disposal) involved in this project?
By the way: You can also find the answers to these and other questions here on our website in the FAQ section.
We sincerely thank all visitors for their questions and the lively conversations!

Background: GeoLaB aims to research the environmentally friendly and safe geothermal use of crystalline rocks. An underground laboratory for geothermal research is planned for this purpose. This is to be built in the Odenwald or the Black Forest.

In the Odenwald, the area around the Tromm is of scientific interest. The rock here is similar to the deep rock that can be used geothermally to generate heat, e.g. deep underground in the Upper Rhine Graben. In contrast to this deep rock, the rock in the ridge of the Tromm is accessible to science. Experiments can be carried out here in a controlled manner and observed in space and time. Investigations are currently underway to determine whether the area is actually suitable for the underground laboratory.

These initial information events in Grasellenbach and Rimbach focused on the scientific plans, possible restrictions for local residents during the construction phase and possible economic development opportunities for the region.

Thank you for your interest, your questions and a lively discussion. If you have any further questions, please do not hesitate to contact us.