Evaluating Flensburg's geothermal potential

Stadtwerke Flensburg and Innargi have evaluated Flensburg’s geothermal potential in Flensburg.

Together with Stadtwerke Flensburg, Innargi has investigated whether Flensburg’s subsurface has sufficient potential for a climate-neutral heat supply with geothermal energy. The work has now been concluded.

Innargi has extensively analysed and evaluated data material from Flensburg’s subsurface as well as the district heating network. The process has been concluded faster than expected. The results show that Flensburg’s subsurface does not have enough potential to provide heat generation based on hydro-geothermal energy.

“We have been able to establish an exemplary open and trusting collaboration with Stadtwerke Flensburg within a short time, and therefore been given the opportunity to make an assessment quickly. There is warm water in the subsurface of Flensburg, but there is too little of it and the temperatures are too low to be able to use it as a heat source.”
Torben Krarup
Head of Subsurface, Innargi.

No costs were incurred for the municipal utilities in this project, as the Innargi has completely taken responsibility for this. Torben Krarup explains: “In Innargi, we are convinced that geothermal energy should not only be sustainable as a renewable energy source but must also be economically sustainable for households. That is why we recommend that Stadtwerke Flensburg pursue other ways to decarbonise the heat supply, as they do.”

Even if the subsurface does not have enough potential according to today’s technical possibilities, the topic of geothermal energy is now finally put on file at the municipal utilities. There are various research projects and ideas for new geothermal technologies that could make a re-evaluation useful if they reach the appropriate technical maturity. The municipality will regularly monitor this and examine whether there is something suitable for Flensburg.

Karsten Müller-Janßen, Head of the Plant Engineering Division at Stadtwerke Flensburg adds: “The current result of the geothermal investigation does not change the fact that by 2035 we want to make Stadtwerke Flensburg climate-neutral, as politically intended and described in our transformation plan. We can now use our resources to concentrate on other components for CO2 reduction, such as heat pumps.”

“Innargi has examined this very carefully and, thanks to the good cooperation with Innargi, we now have clarity that Flensburg’s subsurface resources are currently not sufficient for geothermal energy. However, this may be quite different in other regions or cities.”
Dr. Tom Trittin
Senior Management consultant at Stadtwerke Flensburg

About Stadtwerke Flensburg GmbH – climate neutral by 2035

As an environmentally conscious energy supplier, Stadtwerke Flensburg supplies around 60,000 households in the Flensburg region with electricity, district heating and drinking water. By 2025, the Flensburg-based energy supplier will be expanding its fibre-optic network nationwide throughout the city. Internet, telephone and TV are part of the offer for private and business customers.

The company sells electricity to private and business customers as well as natural gas in Schleswig-Holstein throughout Germany.

682 employees, including 54 trainees, are employed by one of the largest employers and training companies in Flensburg. Stadtwerke is one of the most important heat suppliers in Germany. More than 90% of all Flensburgers receive their heat in an environmentally friendly way by cogeneration from the municipal utilities.

Stadtwerke Flensburg is a 100% subsidiary of the city of Flensburg. Decarbonisation and digitalisation are core business topics. Stadtwerke Flensburg wants to become climate-neutral by 2035 if all the basic conditions allow it.

More info about Innargi A/S:

Innargi A/S is currently building the largest geothermal plant in the EU in Aarhus, Denmark, with a capacity of 110 megawatts. It will supply 36,000 households, or about 20% of the city, with renewable and emission-free heat.

With the expert knowledge of an experienced team of geologists, reservoir, energy plant, and drilling engineers as well as specialists with many years of experience in the district heating industry, Innargi has the necessary combination of know-how to be able to exploit the potential of geothermal energy in order to decarbonise heat supply.

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Contact for Additional Information

Stephan Ghisler-Solvang, Director Communication & Public Affairs

Phone: +45 61 22 93 92

E-Mail: [email protected]