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“ 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 incorporate geothermal ,” says Robert Uggla , chief executive officer of AP Møller Holding .
HEAT FROM THE EARTH ’ S INTERIOR Geothermal energy is heat energy coming from the earth ’ s interior . Two to three kilometres down in the Danish subsoil , in many places there is 60 – 80-degree 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 the upcoming facilities .
The district heating of the future rests on an interplay between many different green energy sources : solar , surplus heat , seawater and geothermal . 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 ”, said Bjarne Munk Jensen .
With the plant in Aarhus , it is possible to reduce the amount of wood pellets that must be imported at 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 example , 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 of the involved parties or consumers will get any 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 is currently received , and this with an agreement realised without financial support from the state .
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 .”
Councillor 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 , 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 .” RACA
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RACA Journal I March 2022 www . hvacronline . co . za