Local, emission-free and base-load capable: Geothermal energy is considered an essential building block of the energy transition. With GeoLaB, a new and unique research infrastructure directly underground, the Karlsruhe Institute of Technology (KIT), the German Research Centre for Geosciences GFZ and the Helmholtz Centre for Environmental Research UFZ now want to accelerate research and prepare the technology for widespread use. The project is to be realised in either 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 underground is available regardless of the time of year or day, which makes geothermal energy base-load capable. It is also renewable, as heat flows back into the reservoir due to temperature conditions and transport processes.

"Geothermal energy has huge potential. In Germany alone, we could use it to replace a third of the gas demand 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 Research Field Energy of the Helmholtz Association. "But to ensure that we can use the necessary technologies safely and that the environmental impact remains minimal, we will now develop geothermal energy accordingly with the help of GeoLaB."

Experiments directly underground

The new large-scale research infrastructure, the Geothermal Laboratory in the Crystalline Basement, or GeoLaB for short, will be used to research fundamental questions of reservoir technology and borehole safety of geothermal plants directly underground. To this end, the project partners of the Helmholtz Association, together with external partners under the leadership of KIT, are developing a new mine in the Black Forest or Odenwald. After the mine has been excavated, a tunnel about one kilometre long 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 experiments in the rock with flow rates relevant for geothermal energy, will be carried out under the thickest possible rock layer of approximately 400 metres.

As a joint research infrastructure of the Research Fields Energy and Earth and Environment, the Helmholtz Association is investing 35 million euros in GeoLaB as a strategic expansion investment. For the construction of GeoLaB, KIT (as the coordinating Helmholtz Centre and representing the partners GFZ and UFZ) is entering into a cooperation with the Bundesgesellschaft für Endlagerung GmbH (BGE).

With the participation of BGE, synergies between the two major societal tasks, energy transition and nuclear waste disposal, are to be utilised. The mining expertise for the construction of the GeoLaB is also to be made available to the BGE. However, a final repository will not be constructed at the site, as the unstable geology in or around the Upper Rhine Graben would not be suitable for this. Instead, the BGE would like to build up fundamental experience and expertise in the construction of a mine in crystalline rock.

Basic research and a rapid transfer of knowledge

"With the underground laboratory, we are entering new scientific territory and taking geothermal research worldwide a decisive step further," says Professor Oliver Kraft, Vice President for Research at KIT. "Using state-of-the-art methods, we are able to record thermal, hydraulic, chemical and mechanical parameters. In this way, we are gaining a fundamental understanding of geothermal transport processes and will also make a significant contribution to safety research for geothermal energy."

With regard to a rapid transfer of the research results into practical applications, the Scientific Director of the GFZ German Research Centre for Geosciences, Professor Susanne Buiter, adds: "The heat from the depths is a mineral treasure that we have not yet sufficiently researched, let alone put to use. However, we need not only the data for this, but also rapid approval procedures and an open dialogue with citizens. Here, too, the research in GeoLaB will make important contributions and enable a knowledge-based approach. In this way, different forms of geothermal energy could soon make a major contribution to the heat transition in many urban areas."

Research helps minimise risks

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

In most cases, however, the necessary flow rates can only be achieved there through appropriate upgrading measures, the expert explains. "A crucial task of the 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 the GeoLaB will significantly expand knowledge about the complex processes in crystalline rock under increased flow rates. The findings would then be transferable to other crystalline reservoirs worldwide.

Applied research with modern methods

According to Professor Ingo Sass, Head of the Geoenergy Section at the GFZ and Professor of Applied Geothermal Energy at the Technical University of Darmstadt, GeoLaB is being built specifically in the crystalline subsurface: "Because we know that the majority of major German cities have this type of rock at depths that can be reached by drilling. 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 digitalisation of underground laboratories," says Professor Olaf Kolditz from the Helmholtz Centre for Environmental Research - UFZ. "With a digital twin (Virtual GeoLaB), there will be modern data storage combined with integrated process models to better plan and evaluate experiments and to look into the future. Virtual reality methods, which have already proven themselves in other underground laboratories, will also be used - also to make the complex processes underground visible and understandable."

GeoLaB as an investment in the future

"The use and development of state-of-the-art observation and evaluation methods with GeoLaB will shape the safe and ecologically sustainable use of geothermal energy and underground space for generations to come," says GeoLaB's technical coordinator, Professor Eva Schill, who heads the Geoenergy Cluster at KIT's Institute for Nuclear Waste Disposal (INE) and is also involved in GeoLaB with TU Darmstadt. "As an interdisciplinary and international research platform, GeoLaB will generate synergies and set standards in research in cooperation with our research partners, industry and specialised authorities."

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

Further information: https://www.geolab.kit.edu/

Scientific contact:

Prof. Dr. Ingo Sass
Section head Geoenergy
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Telegrafenberg
14473 Potsdam
Phone: +49 331 288-27598
Email: ingo.sass@gfz-potsdam.de

Media contact:

Dr. Uta Deffke
Public and Media Relations
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Telegrafenberg
14473 Potsdam
Phone: +49 331 288-1049
Email: uta.deffke@gfz-potsdam.de