Thermal water has been pumped for the first time at the Graben-Neudorf geothermal project of Deutsche Erdwärme near Karlsruhe, Germany. The start of the “discovery test” is a major milestone for the project which will provide crucial information about the productivity and potential of the geothermal well.

Drilling of the well at Graben-Neudor started in mid-2022. The well was drilled to a depth of approximately 3900 meters, targeting a reservoir at the Buntsandstein, which has a high natural permeability and temperatures above 160 degrees Celsius.

A water vapor column about ten meters high signaled the successful start of the test. Thermal water with a brownish color and metallic odor was pumped into a specially designed water basin next to the derrick. One of the main objectives of the test is to assess if the water has the temperature and flowrate to support the target thermal capacity of 40 MW.

The discovery test is expected to last several days. Seismic monitoring remains continuously active. Data from the seismic monitoring can be viewed publicly on the project website.

If the discovery test is successful, the next step would be to try and pump the water back underground. However, this will need further approval from the Freiburg mining authority.

Should everything go according to plan, a combined geothermal power and heat plant can be operational at Graben-Neudorf in two years. Deutsche ErdWärme is also developing geothermal projects in Dettenheim, Waghäusel, and Karlsruhe-Neureut.

Earlier this year, Munich-based artist Ekkeland Götze made an art piece using earth or soil from the Graben-Neudorf geothermal site. The soil was collected at various points, from the borehole to the geothermal power plant. With material from the depth, the artist described the piece as the “deepest” work of art in the world.