Where wind turbines and solar cells depend on the weather, the hot water in the subsoil is a renewable energy source that we can use every day of the year. Aarhus will use this to make district heating even greener.
What is geothermal?
A few kilometers below the Earth’s surface, hot water flows in cavities between porous sandstones. The heat flowing from the Earth’s interior is heating the water.
Under large parts of Denmark – i.a., under Aarhus – the water flows freely between these cavities. It creates enormous reservoirs of hot water, which can be pumped up and used as a renewable energy source.
This type of renewable energy is called geothermal.
How geothermal district heating works
When we transfer the heat from the hot water in the subsoil to the water in the district heating network, it takes place in a closed circuit:
We pump up hot water from the subsoil to a geothermal plant.
In the geothermal system, we then transfer the heat from the water to the water in the district heating system — the cooled water from the subsoil we pump directly back to the same depth.
Why is geothermal climate-friendly?
Geothermal energy is a renewable energy source, as are solar and wind. But where wind turbines and solar cells depend on particular weather, geothermal heat is available every day of the year.
In Aarhus, geothermal district heating can cover approx. 20% of district heating consumption, allowing the city to save on other energy sources and reduce the need to burn straw and biofuels. We expect geothermal energy to reduce annual CO2 emissions by approx—165,000 tons in Aarhus.
Aarhus will get geothermal district heating in 2030
AffaldVarme Aarhus collaborates with Innargi A / S to bring geothermal district heating to the city. Innargi is responsible for drilling and establishing geothermal plants.
Of course, it takes time to drill up to 3 km into the subsoil, and the plan is that the inhabitants of Aarhus can start warming up with geothermal district heating in 2030.
Who is Innargi?
Innargi originates from A.P. Møller Holding, which has 50 years of experience in drilling in the North Sea. Based on that experience and with an expert team of geologists, drilling engineers, reservoir, and facility technicians, Innargi has set out to explore the enormous potential for geothermal energy that is underground.
In Aarhus, Innargi is responsible for all phases – from the first test wells until the heated district heating water is delivered to the inhabitants over the next 30 years.
That is why AffaldVarme Aarhus works with geothermal energy
In 2030, the heat and power from AffaldVarme Aarhus must be climate neutral. Therefore, we will use even greener energy sources – and here, geothermal energy plays an important role.
Geothermal energy is a renewable and stable energy source that is not dependent on specific weather conditions and does not smell, make noise, or pollute. In this way, the inhabitants of Aarhus can get heat and hot water from green geothermal district heating every day for many years to come.
Find more information here