Starting today: Seismic surveys will map the subsurface across Denmark

Starting today: Seismic surveys will map the subsurface across Denmark

News • May 1, 2023

Today, Innargi starts extensive seismic surveys of the subsurface in Aarhus, Holbæk and the Greater Copenhagen area. The aim is to investigate how best to utilize the potential for geothermal energy by mapping the subsurface.

In Aarhus, Innargi is currently developing the largest geothermal plant for district heating in the EU together with the district heating company Kredsløb. And at the end of last year, Innargi signed an agreement with the district heating company Fors in Holbæk and district heating companies HOFOR, VEKS and CTR in the Greater Copenhagen area to investigate the possibilities for geothermal energy there.

In order to gain more knowledge about the subsurface in Aarhus, Holbæk as well as Greater Copenhagen, Innargi will, starting 1 May, conduct extensive seismic surveys of the subsurface.

“The mapping will, among other things, show us more about the layers in the subsurface and how deep we need to drill to find the geothermal water. This is important for our geologists to know when they assess how we can make the most of the hot water under our feet,” says Asbjørn Haugstrup, Director of Communications and Public Affairs at Innargi.

The survey will start in Aarhus on May 1. The four special trucks will then continue to Holbæk, where the surveys will take place between May 4 and 15. In the Greater Copenhagen area, the survey will be carried out between May 15 and June 30.

Innargi is collaborating with the engineering consultancy GEO and the French subcontractor GTG to carry out the seismic surveys.

How the subsurface mapping is carried out

The seismic surveys are carried out by four special trucks sending vibrations into the subsurface along a carefully planned route. The vibrations are recorded by geophones placed along the roadside. They are a kind of microphone the size of a cell phone.

The mapping will take place at night to minimize disruption to traffic. People living near the planned route will see the four white trucks passing by their homes between 10 p.m. and 6 a.m.

If you live nearby, you may hear the trucks passing by and feel some vibrations from about 10 minutes before the trucks pass until 10 minutes after the trucks have passed. The vibrations last for 20 seconds at a time, and they are not dangerous to people or buildings.

Geothermal energy can contribute to the green transition in Denmark

Today, geothermal energy accounts for less than 1% of Denmark’s district heating but has the potential to cover up to 30% of Denmark’s district heating. This corresponds to the heat consumption of 600,000 households. In this way, geothermal energy is important for Denmark’s ambition to be climate neutral by 2045.

Find more information about the surveys and see the routes here (In Danish): www.geotermipåvej.dk