Danish Aarhus announces large geothermal district heating project

Danish Aarhus announces large geothermal district heating project View over the city of Aarhus, Denmark (source: flickr/ IMBiblio, creative commons)
Alexander Richter 14 Jan 2022

The city of Aarhus in Denmark and Danish Innargi, announce a project to develop the largest geothermal district heating system in the European Union.

The geothermal based heating company Innargi, established by A.P. Moller Holding, has entered a 30-year agreement to develop and operate EU’s largest geothermal heating plant in the city of Aarhus, Denmark. By providing circular, constant baseload energy for district heating, Innargi offers a green and sustainable alternative to biomass, coal and gas.

Buildings account for 13% of all greenhouse gas emissions in the EU, equaling 432,000,000 tonnes of greenhouse gasses every year. With large-scale geothermal heating plants, it is possible to heat millions of homes with green energy, also when there is no wind or sun. When geothermal energy replaces hydrocarbon based heating, an average household can reduce its CO2 footprint by up to 6 tonnes per year.

“It is critical to rethink our heating sources and bring geothermal into play when planning the future energy mix. We see a huge potential for geothermal based heating in many European cities that are struggling to phase out coal to meet the climate targets. We believe countries like Denmark, Germany and Poland offer the right subsurface conditions to significantly reduce the need for coal, gas and imported biomass. Today’s announced 30-year agreement is an important first step of our journey. We are very glad to see the strong support from the Danish government and Aarhus municipality, including the trust in our team and technology, to develop, what will become, EU’s biggest geothermal based plant.” so Samir Abboud, CEO at Innargi.

Aarhus municipality has 330,000 citizens and 180,000 households. 95% of the households are connected to the district heating system. The planned capacity of the geothermal heating plant in Aarhus is 110MW, equaling 20% of Aarhus’ district heating demand, and the annual CO2 emissions are expected to be reduced by up to 165,000 tonnes. Subject to a successful appraisal process, the geothermal plant will be completed in 2029 with an expected operation of at least 30 years.

“This is a historic day for district heating in Aarhus, and I am proud that we can continue to make the heat of the Aarhusians ever greener. Geothermal energy is a renewable energy source and thus an important step in our efforts to obtain much more renewable energy into the district heating. Geothermal energy is a prerequisite for us to be able to reach 2030 with the aim of phasing out imported wood pellets, ”says Bjarne Munk Jensen, CEO of AffaldVarme Aarhus.

Innargi will build and operate the 110 MW geothermal plant. In 2025, the plant may begin to supply heat to the people of Aarhus, and the plant is scheduled to be fully expanded by 2030, when it will cover approx. 20% of the district heating demand.

Denmark is at the forefront

The expectation is that the project will inspire many large cities in Europe working on phasing out of coal and gas. That is also the ambition of A.P. Møller Holding, which founded Innargi in 2017.

“We founded Innargi because we wanted to bring our underground competencies into play for the benefit of the green conversion. Geothermal energy can provide heat regardless of whether the sun is shining or the wind is blowing, and therefore used as base heat as a replacement for coal, gas and biomass. It has a positive influence on greenhouse gas emissions, as the direct emissions from buildings account for 13% of total greenhouse gas emissions in Europe. We see great opportunities to develop green heat for the people of Aarhus and hopefully millions of homes in European cities where there is political willingness to geothermal, ”says Robert Uggla, CEO of A.P. Møller Holding A / S.

Press meeting – January 14, 2022 of Innargi, AffaldVarme Aarhus and city of Aarhus (source: AffaldVarme)

Heat from the earth’s interior

Geothermal energy is heat energy coming from the earth’s interior. Two to three km down in the Danish subsoil, in many places there is 60-80 degrees hot geothermal water. In a geothermal plant the hot geothermal water is pumped up to the surface, where the heat is harvested and transferred to the water in the district heating network in a closed circuit. The geothermal water is then pumped back into the subsoil. The energy source is inexhaustible.

Specifically, Innargi will now drill the first exploration wells in Aarhus. They must show whether the subsoil can provide the expected heat and provide the final knowledge for the final design of it upcoming facilities.

The district heating is getting even greener

The district heating of the future rests on an interplay between many different green energy sources: solar, surplus heat, seawater, geothermal, etc. For AffaldVarme Aarhus, it’s about getting the different sources to play intelligently together so that the consumer price of heat is always the best possible.

“Geothermal energy plays a key role here, because geothermal energy is a secure source of renewable energy, that can supply heat 365 days a year. Geothermal energy is thus a crucial step towards that burn less biomass in the future, ”says Bjarne Munk Jensen.

With the plant in Aarhus, it is possible to reduce the amount of wood pellets that must be imported 55,000 tons per year. This means that direct biogenic CO2 emissions are reduced by 95,000 tonnes, and if the saved biomass is used for eg methanol for transport, further savings can be made 70,000 tonnes of CO2 – equivalent to emissions from 30,000 petrol cars.

Innargi takes the underground risk

The biggest risk associated with geothermal is that the subsoil cannot deliver the expected heat, or that underground-related operational problems arise during the expected life of the plant of 30 years. Innargi carries the underground risk in all phases of the project. That way, neither AffaldVarme gets Aarhus or consumers unforeseen expenses if something does not go as planned.

The project also provides a plus on the economy. The heat from the plant will be significantly cheaper than the heat that AffaldVarme currently receives from Studstrupvaerket, and this with an agreement realized without financial support from the state.

ATP and NRGi are investing in the spread of geothermal energy

At the same time as the agreement between AffaldVarme Aarhus and Innargi is announced, ATP and NRGi as a co-investor in Innargi Holding A / S. Thus, Innargi can reach out to the many opportunities that arise in both Denmark and Europe when heat production in the big cities is to made CO2-neutral.

“While sun and wind come and go, the heat from the inside of the earth is always there. It makes geothermal one stable renewable energy source. It is necessary if we are to succeed in the green transition. We is at ATP proud to enable a project with a huge Danish and international potential, where at the same time, there will be returns to pick up in the long run for our members, ”says Bo Foged, CEO of ATP.

For NRGi, the investment is also about supporting the integration between the electricity and heating sector. “At NRGi, we work for the green transition. We want to increase the amount of renewable energy by investing in new renewable energy projects – an ambition that was further strengthened in 2021, where we entered into a partnership agreement with Sampension. And then we focus on the interaction between the electricity and heating sector, where geothermal energy is a way of using electricity for heating. The flagship project in Aarhus will hopefully be copied in many cities, while at the same time supporting it in itself strategic energy planning, which all major energy players work with in Aarhus, ”says CEO. director Jacob Vittrup from NRGi.

The agreement on capital increase is awaiting the Danish Energy Agency’s approval.

Mayor of Aarhus Jacob Bundsgaard: “In Aarhus, we have an ambitious goal of being a CO2-neutral city by 2030. In that account, the heat supply to the citizens and companies means a lot. Therefore, it is a great pleasure that Aarhus now can take the first steps in a very ambitious and green project where 20% of the heat comes from one new renewable energy source. ”

Councilor for Environment and Technology in Aarhus, Steen Stavnsbo: “Geothermal energy is green energy and is an important piece in a modern and future CO2-neutral energy system. With geothermal energy as a new, renewable heat source, our heat supply will be greener, and this will bring Aarhus closer to the ambition of being climate neutral. In the long run, is it is a project that has a potential that extends far beyond the municipal boundaries and the surrounding municipalities, which we currently supply with district heating. ”

Source: Innargi & AffaldVarme Aarhus