Karlsruhe Institute of Technology: GeoLaB- future with geothermal energy

Local, emission-free and capable of base load: Geothermal energy is considered an essential component of the energy transition. With GeoLaB, a new and unique research infrastructure directly underground, the Karlsruhe Institute of Technology (KIT), the German Research Center for Geosciences GFZ and the Helmholtz Center for Environmental Research UFZ now want to accelerate research and prepare the technology for widespread use. The project is to be implemented either in the Black Forest or the Odenwald, and the Helmholtz Association is funding it with 35 million euros.

In order to achieve climate neutrality and at the same time become less dependent on energy imports, the use of deep geothermal energy is suitable in most regions of Germany. Heat from the subsoil is available regardless of the time of year or day, which makes geothermal energy suitable for base loads. In addition, it is renewable, because due to the temperature conditions and the transport processes, heat flows into the reservoir.

“Geothermal energy has huge potential. In Germany alone, we could replace a third of the gas required for our heat – and in view of the climate catastrophe and the geopolitical world situation, we can no longer do without it,” says Professor Holger Hanselka, President of KIT and Vice President for the Energy Research Area of ​​the Helmholtz Association. “But so that we can also use the necessary technologies safely and the environmental impact remains minimal, we will now further develop geothermal energy accordingly with the help of GeoLaB.”

Experiments directly underground

With the new large-scale research infrastructure, the Geothermal Laboratory in the Crystalline Basement, GeoLaB for short, fundamental questions of reservoir technology and borehole safety of geothermal systems are to be researched directly underground. To this end, the project partners of the Helmholtz Association, together with external partners under the leadership of KIT, are excavating a new mine in the Black Forest or Odenwald. After the expansion, an approximately one kilometer long tunnel will lead to caverns. From there, in this world’s first underground research laboratory for deep geothermal energy, controlled high-flow experiments, i.e. flow tests in the rock with flow rates relevant for geothermal energy, are carried out under a rock layer of about 400 meters that is as thick as possible.

As a joint research infrastructure for the research fields Energy and Earth and Environment, the Helmholtz Association is investing 35 million euros in GeoLaB as a strategic expansion investment. In order to set up GeoLaB, KIT (as the coordinating Helmholtz center and on behalf of the partners GFZ and UFZ) enters into a cooperation with the Bundesgesellschaft für EndRepository GmbH (BGE).

With the participation of the BGE, synergies between the two major social tasks, energy transition and nuclear disposal, should be used. The mining competences for the construction of the GeoLaB should also be made accessible to the BGE. However, no repository will be built at the site, and a turbulent geology such as in or on the Upper Rhine Graben would not be suitable for this either. Rather, the BGE would like to build up basic experience and skills when driving a mine in crystalline rock.

Basic research and rapid knowledge transfer

“With the underground laboratory, we are breaking new scientific ground and taking geothermal research a decisive step forward worldwide,” says Professor Oliver Kraft, Vice President for Research at KIT. “Using the latest methods, we are able to record thermal, hydraulic, chemical and mechanical parameters. In this way we will gain a fundamental understanding of the geothermal transport processes and will also make a significant contribution to safety research for geothermal energy.”

With regard to a rapid transfer of research results into practical application, the scientific director of the GFZ German Research Center for Geosciences, Professor Susanne Buiter, adds: “The heat from the depths is a natural resource that we have not yet adequately researched, let alone put to use to have. We not only need the data for this, but also rapid approval procedures and an open dialogue with citizens. Here, too, research in GeoLaB will make important contributions and enable a knowledge-based approach. Different forms of geothermal energy could soon make a major contribution to the heat transition in many urban areas.”

Research helps to minimize risks

The fact that geothermal energy has so far only been used selectively in Germany is partly due to citizens’ concerns about artificially caused earthquakes. “These occur primarily when fluids are improperly injected into a reservoir,” says Professor Thomas Kohl from the Institute for Applied Geosciences (AGW) at KIT and scientific coordinator of the project. In principle, however, the application of such enhanced geothermal systems (EGS) is necessary in order to make the great potential of geothermal energy economically usable, regardless of location, even in regions with crystalline bedrock. These layers of rock have the greatest potential for geothermal energy and are fundamental to future energy security.

In most cases, however, the necessary flow rates can only be achieved there through appropriate upgrading measures, explains the expert. “A decisive task of research with the GeoLaB will therefore be to improve the understanding of induced seismicity and to experimentally demonstrate measures to prevent it,” says Kohl. He expects that the experiments in GeoLaB will significantly expand knowledge about the complex processes in crystalline rock under increased flow rates. The findings could then also be transferred to other crystalline reservoirs around the world.

Application-oriented research with modern methods

For this reason, GeoLaB is being erected specifically in the crystalline subsoil, according to Professor Ingo Sass, Head of the Geoenergy Section at the GFZ and Professor for Applied Geothermal Energy at the TU Darmstadt: “Because we know that the vast majority of German cities have this type of rock that is more accessible with drilling have depth. The transfer effect of GeoLaB can therefore be of enormous importance for the heat transition in metropolitan areas.”

“With GeoLaB, we also want to set new standards for the digitization of underground laboratories,” says Professor Olaf Kolditz from the Helmholtz Center for Environmental Research – UFZ. “With a digital twin (Virtual GeoLaB), there will be modern data storage combined with integrated process models in order to be able to better plan and evaluate experiments and look into the future. Methods of virtual reality are also used, which have already proven themselves in other underground laboratories – also so that the complex processes underground become visible and understandable”.

GeoLaB as an investment in the future

“The use and development of state-of-the-art observation and evaluation methods with the GeoLaB will shape the safe and ecologically sustainable use of geothermal energy and the underground space for generations,” says the technical coordinator of GeoLaB, Professor Eva Schill, who runs the geoenergy cluster at the institute for Nuclear Waste Management (INE) of the KIT and is also involved with the TU Darmstadt in GeoLaB. “As an interdisciplinary and international research platform, GeoLaB will create synergies and set standards in research in cooperation with our research partners, industry and the specialist authorities.”

GeoLaB also ensures the training of a new generation of researchers and technicians, for which various measures are already being planned. In addition, extensive opportunities for participation are created for citizens. These can, for example, be developed and implemented together with the citizens and interest groups of the region in a co-design process.

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