Aarhus geothermal district heating
Overview
A new geothermal district heating plant is under construction in Denmark's second-largest city of Aarhus. Directed by Danish geothermal-based heating company Innargi in collaboration with local district heating provider AffaldVarme Aarhus and district heating company Kredsløb, the city aims to become home to the largest geothermal district heating system in the European Union.
The launch of drilling operations was marked by a momentous event, showcasing the towering 31-meter tall drilling rig at the Aarhus Harbour. The drilling rig is set to delve to a depth of 2.5 kilometers, a process expected to last several months with the first facility in Skejby to begin delivering heat to Aarhus residents by 2025.
The establishment of geothermal district heating is a crucial step towards Aarhus's goal of becoming carbon-neutral by 2030. With the implementation of geothermal energy, Kredsløb aims to significantly reduce the importation of wood pellets, thereby curbing CO2 emissions and mitigating environmental impact.
Beneficiaries
The new district heating plan will provide heating for thousands of homes, expected to meet 20% of the district heating demand in Aarhus municipality, encompassing 330,000 citizens and 180,000 households.
Anticipated to boast a capacity of 110MW, the geothermal heating plant holds the promise of substantial environmental benefits, with annual CO2 emissions set to plummet by up to 165,000 tonnes.
Geothermal power holds immense promise, blessed with stability and sustainability that surpasses weather-dependent renewables. Despite its potential, geothermal energy remains underutilized in Denmark, comprising less than 1% of district heating. However, research indicates vast untapped potential lying beneath Denmark's subsoil. With the capacity to cover half of the country's heating needs, geothermal energy stands as a formidable ally in the fight against climate change.
Technical details
The plant is expected to be completed by 2029, with an operational lifespan of at least 30 years. The goal is for the entire facility to consist of 17 wells and 7 installations equipped with heat exchangers and heat pumps, which will harness the heat from the geothermal water and convey it to the district heating grid. Before proceeding further, a trial period needs to be initiated. The initial well has already been drilled, water has been extracted to the surface, and the drilling equipment is currently being relocated to Skejbyvej in Aarhus. This testing phase is anticipated to conclude in 2025.
Innargi has extracted approximately 1,500 cubic meters of geothermal water from the well located at the harbour in Aarhus. The surface water temperature was recorded at 75 degrees Celsius.
The innovative system will indeed tap into the earth's core, extracting water from depths of two to three kilometres with temperatures ranging from 60 to 90 degrees Celsius. This heat will then be harnessed and channelled into the district heating network, providing a sustainable source of warmth for Aarhus residents.
Summary
Depth of drilling: 2.5 kilometres
Geothermal power: 110 MW
Units covered: 180,000 households
CO2 emissions avoided: 165,000 tons of CO2
Sources:
Innargi: Green milestone for Denmark: Geothermal drilling has started in Aarhus
Innargi: Geothermal project in Aarhus enters its second test phase
Innargi: project Aarhus
State of green: Arhus announces EU's largest geothermal district heating system
Thinkgeoenergy: Drilling starts for Aarhus