Geothermal drilling achieves deepest well in Frankfurt, Germany

Frankfurt am Main, Germany (source: Marco Verch Professional Photography / flickr, Creative Commons)

Ongoing drilling operations for a geothermal borehole in the Rebstock site in Frankfurt, Germany has now reached a depth of 292 meters. This makes it the deepest borehole ever drilling in the city, as reported by the Hessian State Office for Nature Conservation, Environment, and Geology (HLNUG).

Drilling in Rebstock is part of a research drilling program to investigate the geothermal potential in Frankfurt. Drilling started in November 2022 and aims for a total depth of 800 meters. The research borehole will provide insight on the characteristics of the “Rotliegend,” a potential reservoir rock that is being supplied by geothermal fluids inflowing from the Upper Rhine Graben at depths of more than 2000 meters.

The previous record for the deepest well in Frankfurt was attained back in 1893. The 286-meter borehole was drilled at the Fritz Reutlinger brewery and tapped a resource with a temperature of only 30 degrees Celsius. The borehole was not utilized and was sealed.

At the 800-meter target depth, the geothermal borehole is expected to access water at 40 degrees Celsius. After research drilling, the technical data will be made available on the HLNUG website for future developers, planners, drilling companies, and energy suppliers. The project partners hope to be able to supply the Rebstockbad and the Römerhöfe district with geothermal energy. The investigation is expected to be completed by May 2023.

Source: Frankfurter Rundschau