Geothermal project in Aarhus enters its second test phase

Geothermal project in Aarhus enters its second test phase

Press release • February 8, 2024

The initial test drilling at the Port of Aarhus has been concluded, and Innargi is now moving the drilling rig to Skejbyvej, where the remaining tests will be carried out. In Skejby, the test phase includes two additional wells and a plant that can capture the heat from the geothermal water and transfer it to the water for district heating.

In close collaboration with the utility company Kredsløb, Innargi is in the process of developing a geothermal plant that will supply 20% of district heating to the residents of Aarhus by 2030. The ambition is for the complete plant to comprise 17 wells and 7 facilities with heat exchangers and heat pumps that will capture the heat from the geothermal water and transfer it to the district heating network.

But first, a test phase must be conducted. The first well has now been drilled, water has been pumped to the surface, and the drilling rig is in the process of being moved to Skejbyvej in Aarhus. This test phase ends in 2025.

Innargi has pumped about 1,500 m3 of geothermal water from the well at the harbour in Aarhus. The water temperature at the surface was measured at 75 degrees.

“We are very satisfied with the drilling process at the harbour and the temperature in the reservoir, though we would prefer a higher water production (flow rate). It is too early to conclude anything, as the well at the port is only the initial well of the testing phase. We will continue our work in Skejby, where we also plan to build a plant with heat exchangers and heat pumps and provide heat to Kredsløb, as the culmination of a successful test run. Not until then will we be able to comment on what the final design will look like.”

Lars Heineke,

Project Director at Innargi.

During the testing phase, the temperature, flow rate and chemical composition of the geothermal water are tested. The chemical composition has an impact on which materials will be included in the next wells and thus how expensive they will be to build.

“I am delighted that the first wells at the port have found warm water, so there is cause for cautious optimism. I will be following the upcoming drilling in Skejby with excitement, as geothermal heat will have a huge impact on Aarhus.”

Nicolaj Bang,

Alderman, Technology and Environment, Aarhus Municipality

Thanks to the neighbours

Together, Kredsløb and Innargi have conducted several neighbourhood meetings and sent out newsletters to neighbours close to the drilling site at the Port of Aarhus – and the feedback has been very understanding.

“We have been drilling around the clock and there have been lights on site – and although we do our best regarding soundproofing with an electric drilling rig, we know that the project has been both visible and audible. However, we have encountered an impressive understanding, or rather a curiosity, from the neighbours and have had very few complaints that we have been able to handle with good, direct dialogue. The people from Aarhus are supportive of the green transition. I’d like to thank you for that.”

Bjarne Munk Jensen

CEO of Kredsløb

Kredsløb and Innargi will continue their intensive dialogue with neighbours and informational meetings in Skejby. Most recently, all neighbours were invited to an informational meeting on January 22.

About the Aarhus plant

  • The geothermal heating plant in Aarhus will be the largest in the EU
  • Geothermal energy is expected to cover 20% of the district heating demand in Aarhus
  • In Aarhus, geothermal energy is expected to reduce annual CO2 emissions by approximately 165,000 tons of CO2 (reduction in immediate biogenic emissions and reduction due to alternative use of biomass)

About the partners

Kredsløb supplies district heating to 330,000 people and recycles waste for 170,000 households in Aarhus Municipality. Kredsløb has dedicated itself to making it easy for customers and partners to contribute to the green transition.

Innargi A/S was founded in 2017 by A.P. Møller Holding A/S and is today owned by A.P. Møller Holding, ATP, NRGi, and Sampension. Innargi’s mission is to enable geothermal energy as a source of heat in millions of homes with the expertise of an experienced team of engineers including geologists, reservoir, facility and drilling engineers, as well as through partnerships with district heating experts.


Learn more about the Aarhus Project

Kredsløb and Innargi have signed a 30-year agreement for the development and operation of the facility. In November 2023, drilling of the first of a total of 17 wells started. In 2025, we expect to deliver the first heat.

You can follow the progress of the project here.

Aarhus, Denmark