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Energy from deep down: geothermal research platform in Groß Schönebeck celebrates its 25th anniversary

For a quarter of a century, Groß Schönebeck in Brandenburg has been home to researchers studying the geological underground to find sustainable ways of harnessing deep geothermal energy. These research findings cover the entire process chain, from exploring the reservoir to converting the energy after extraction.

What are the safest ways of exploring reservoirs with a potential for geothermal energy? What are ways to sustainably increase the productivity of thermal water? These are just two of the many research questions that have been studied at the Groß Schönebeck geothermal research platform in the past 25 years. The overarching objective is to use energy from deep down to turn it into heat and electricity.

Over time, the underground lab located approx. 50 kilometres to the north-east of Berlin has earned a reputation among international experts as an important scientific site for studying deep geothermal energy. The platform is operated by the GFZ Helmholtz German Research Centre for Geosciences.

Potential of deep geothermal energy

Deep geothermal energy draws on heat that is present naturally, 400m to several kilometres below the surface. Geothermal energy can provide base load power. Unlike wind or solar energy, it is continuously available, irrespective of the climate or season. Geothermal energy also comes with the advantage of very low carbon dioxide emissions. Geothermal energy makes sense for ecological reasons. With rising gas and petroleum prices, it is also becoming an interesting alternative from an economic point of view.

There are various regions in Germany that invite the use of geothermal energy for heat supply due to their geological conditions. These include the North German basin, which stretches across large parts of northern Germany. The presence of aquiferous rock and high underground temperatures means that there is high potential for the use of hydrothermal energy. Groß Schönebeck is a location situated at the southern edge of this region. The geothermal lab there is used as a reference site for the development of geothermal technologies for harnessing energy from rock reservoirs with low permeability.

Rooted in exploration drilling for natural gas

Today’s research site goes back to a former test drilling project for natural gas exploration. Beginning in 2001, adjustments were made to prepare the site for geothermal research. Five years later, a second deep borehole was drilled, allowing for a geothermal doublet to be established and tests to be run for harnessing hydrothermal heat. The first borehole is used to bring hot thermal water up from the depth. The heat is then used in the overground installation, before the water is sent back underground via the second borehole. Ever since this setup was put in place, researchers have been conducting a large number of experiments for optimisation and for harnessing the highest possible amounts of thermal water.

The two boreholes, which tap reservoirs as hot as 150° Celsius located at a depth of between 3.9 and 4.4 kilometres below the surface, continue to form the heart of the research platform in Groß Schönebeck. The structure of the sediment basins there is quite common across the world: the basins consist of several layers of rock holding hot water.

Over the past 25 years, research teams in Groß Schönebeck have implemented a number of different projects supported under the Federal Government’s Energy Research Programme. These include PERFORM and PERFORM II. The projects all aimed at improving the performance of geothermal systems. The RISSDom-A project has allowed researchers to study how artificial or natural fissures affect a given reservoir’s productivity. The project marks the first time that 3D vibroseismic studies were conducted at the Groß Schönebeck geothermal site, resulting in data that allowed for a detailed characterisation of the fissured and porose reservoir layers. Another project at Groß Schönebeck that received public-sector funding looked into the feasibility of geothermal electricity generation from deep hydrothermal reservoirs. In the course of this project, researchers further expanded the boreholes of the geothermal lab and set up a thermal water circuit.

Research site celebrates 25th anniversary

At the end of June, Groß Schönebeck celebrated the 25th anniversary of its research site by hosting a festive event. Researchers at the GFZ Helmholtz German Research Centre for Geosciences and their guests looked back at the site’s scientific and technological success stories over time. They also used the opportunity to present their ongoing projects and discuss ideas for the future with representatives from science, industry and government, and with local residents.

25 years of research in Groß Schönebeck stands for a continuous expansion of knowledge about the geological underground and about the sustainable use of deep geothermal energy. From finding a good use for an old borehole to building a geothermal doublet with the help of a new borehole, to installing a thermal water circuit, and to materials analyses to work on energy procedural technologies: the infrastructure at the site has been incrementally expanded by scientists whose geothermal research will certainly continue to provide new insights.