Geothermal research drilling ongoing in Frankfurt, Germany

Skyline of Frankfurt/ Germany (source: flickr/ /xingxiyang, creative commons)

A research drilling programme is currently ongoing to investigate the geothermal potential in the Rebstock site in Frankfurt, Germany. Drilling has been ongoing since November and is expected to be completed by March 2023. The drilling contract has been awarded to Daldrup & Söhne AG.

Previous investigations in the area have indicated that there is a geothermal resource with a temperature of 40 degrees Celsius at a depth of 800 meters. The research borehole is intended to provide more insight into the geothermal anomaly to better determine if geothermal energy can be used to supply heat to the city. The heat can conceivably be used for large building complexes, or possibly new construction projects in Rebstockbad and Römerhöfe.

Research drilling is planned to a depth of 700 to 800 meters, possibly making the borehole the deepest in the Frankfurt city area. The research borehole will provide insight on the characteristics of the reservoir rock – the so-called “Rotliegend.” The composition of the thermal water will also be analyzed. This thermal water is inferred to be supplied by an inflow from the Upper Rhine Graben at depths of more than 2000 meters.

Funding for research drilling is being provided by the Hessian State Office for Nature Conservation, Environment, and Geology (HLNUG). The Leibniz Institute of Applied Geophysics (LIAG), the Technical University of Darmstadt, the Technical University of Freiberg, and Vulcan Energie Resources GmbH were all partners in planning the scope of the investigation.

After research drilling, the technical data will be made available on the HLNUG website for future developers, planners, drilling companies, and energy suppliers. A similar study had just recently been reported in the city of Offenbach.

There are currently around 250 geothermal probe systems installed in Frankfurt with a total heating capacity of around 10,000 kW. There are currently no medium-depth geothermal projects in Frankfurt, but this may change based on the findings of research drilling at Rebstock.

Source: Zfk and Bundesverband Geothermie