Utrecht University: Research into ultra-deep geothermal energy in Utrecht East stops, but research into less deep geothermal heat continues

There is insufficient certainty about the presence of ultra deep heat in the subsurface of Utrecht East for the further development of ultra-deep geothermal energy (UDG). This has been shown by seismic research carried out by Energie Beheer Nederland (EBN). Based on this finding, the Gold consortium (Geothermie Oost Utrecht Duurzaam) has had to decide to terminate the research project. With possible options lying between two and three kilometres (a little less deep) in the ground, geothermal heat is still in the picture as a sustainable source of heat for the area.

Making it gas free
On the basis of a joint sustainable energy demand and a climate-neutral future in Utrecht East, Utrecht University, Utrecht University Medical Center, Stichting Kantorenpark Rijnsweerd and energy specialist EQUANS joined forces nine years ago. Over the past few years, Utrecht University, as part of the Gold Consortium, has been investigating the possibilities of using sustainable geothermal heat to make the buildings and offices in the area gas-free.

At the right depth
Gold was a project within the Green Deal Ultradiepe Geothermie (UDG), a collaboration between the national SCAN programme of the Ministry of Economic Affairs and Climate, EBN, TNO and five consortiums. Based on seismic data from SCAN, an attempt was made to map the depth and thickness of the targeted limestone layer as accurately as possible. “First of all, we wanted to know whether the limestone layer was present at a certain depth. Every kilometre you go into the ground it gets about thirty degrees warmer. Add to that the surface temperature and at a depth of five to six kilometres you will find a temperature of around 180 degrees Celsius.”


Rob Mathlener is speaking. As interim head of the Energy team at Utrecht University, he is responsible for making the university’s energy supply more sustainable. This means a direct interest in geothermal energy. Especially for Gold, extra seismic lines were shot in addition to SCAN. These extra lines were paid for by the municipality of Utrecht, the province of Utrecht and the partners in the Gold consortium. Mathlener: “Through this cross about Utrecht Oost we now know much more, but unfortunately the images did not provide enough clarity for a follow-up.”

‘Of course it is a pity that Gold stops after nine years. But with this outcome we have found an answer to our central research question and laid a basis for further research’
“Of course it is a pity that Gold stops after nine years. But with this outcome we have found an answer to our central research question and laid a basis for further research”, continues Rob Mathlener. “Can we extract heat from earth layers deeper than four kilometres to make the Utrecht Science Park and the neighbouring Rijnsweerd office park more sustainable? With the data that the current technology provides, we cannot answer with a ‘yes’. This insight may change in the future once more research has been done, but at the moment the knowledge of the subsurface does not offer sufficient certainty for the commercial development of ultra-deep geothermal energy.”

Research into less deep geothermal energy
In the coming years, EBN will be carrying out research drilling to the east of Utrecht into the application of geothermal heat from earth layers that are less deep in the ground. Whether the research by EBN paves the way for a possible sequel for geothermal heat production in Utrecht East is still in the future, according to Matlener. “We leave further research to market parties. Naturally, Utrecht University is always willing to help find a way to make the heat supply in the area more sustainable.”

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