Research project shows the way for geothermal energy in Denmark

Published 19-11-2020

The Danish underground holds an enormous, unexploited geothermal potential. That is the conclusion of the recently finished research project Geotherm, which GEUS has done in collaboration with partners from the world of research, the industry and the district heating sector.


Today, approximately 60 % of Danish households are supplied with district heating. Just under half of that district heating comes from non-renewable energy sources, e.g. coal and natural gas. And only 0.1 % of the district heating from renewable energy sources comes from geothermal energy. However, this is not the case because the preconditions for geothermal energy are poor in Denmark – on the contrary:

“We know that the Danish underground contains significant geothermal resources and we also estimate that a large part of the Danish households could be heated with geothermal energy,” says Lars Henrik Nielsen, project manager and Head of Department for Stratigraphy at GEUS.

Known methods from the oil industry

According to Lars Henrik Nielsen, the reason that geothermal energy is not more widespread in Denmark is the large geological, technical and financial uncertainties connected to establishing a geothermal power plant. Thus, the aim of the Geotherm project has been to reduce those uncertainties.

“A significant barrier to the establishment of a large-scale geothermal energy production in Denmark is the uncertainty in the geological prognosis – meaning the risk of drilling in an area where the underground subsequently turns out to be unsuitable as a geothermal reservoir. Therefore, an important purpose for the Geotherm project was to optimise the geological prognosis and minimise the risk of useless and costly drillings,” Lars Henrik Nielsen says.

In order to do that, the researchers have adopted and adapted methods known from the oil and gas industry to make detailed descriptions of the geological layers and map possible geothermal reservoirs in the underground.

“Going forward, the results from the Geotherm project will make it easier to estimate where it makes sense to look for the geothermal resource – meaning where both infrastructure and the right type of underground are present,” Lars Henrik Nielsen says.

Best practice reports

As part of the project, the research team has produced a number of best practice reports and concluding reports, presenting the data and results of the project. The reports contain recommendations on how to obtain the best possible data to reduce the geological risks in geothermal projects, which types of materials that are most suited, and how to estimate whether a geothermal project can become profitable and should continue.

At GEUS, the work to improve the conditions for geothermal energy in Denmark continues.

“We will continue our efforts to reduce the geological risks in close collaboration with other partners in the field. In that regard, we hope to get an opportunity to add a calculation module to our geothermal energy portal, which can estimate the amount of heat that can be utilised in a given place,” Lars Henrik Nielsen says.

Lars Henrik Nielsen
Chief Consultant
Henrik Vosgerau
Senior Researcher
Geophysics and Sedimentary Basins
Anders Mathiesen
Senior Adviser
Geophysics and Sedimentary Basins


The project was supported by the Innovation Fund Denmark and consists of 11 partners:

GEUS, University of Aarhus (AU), FORCE Technology, Geoop, Qeye Labs Aps, Helmholtz–Zentrum Potsdam Deutsches GeoForschungsZentrum (GFZ), Bureau de recherches géologiques et minieres (BRGM), University of Lund (LU), HGS (c/o HOFOR District Heating) and the two geothermal energy plants in Sønderborg and Thisted.