“Simple, cheap and green”: Geothermal district heating in Vridsløsemagle, Denmark
Overview
Located in the Northeast of Zealand, Denmark, the small town of Vridsløsemagle is warming up with healthy and sustainable heat thanks to its new geothermal district heating system.
Too far from the nearest city, and with a very modest heat demand, Vridsløsemagle couldn’t feasibly be connected to a traditional district heating system. The solution was to install a community networked geothermal system.
Heat is extracted from 23 vertical 200-meters-deep geothermal boreholes and recovered from the uninsulated pipes of the network. Then, it is distributed to the connected households, just like any other district heating system.
“We’re getting a shared solution that is simple, cheap, and green. We avoid having to see and hear a lot of individual heat pumps, and the economics are just as good. We also avoid the responsibility for operation and maintenance, so in my view, it’s a win-win-win.” - Christian Thomsen, inhabitant of Vridsløsemagle
A success story
To kickstart this project, Høje Taastrup (HTF) - Denmark's biggest consumer-owned heating company -, needed at least 35 families interested in joining the network. To bring them onboard, HTF organised public meetings and raised awareness about the benefits of a district heating system. As a result, 50 households expressed their interest, almost half of the town’s population.
“This could work well in many places. Collective solutions make sense — they are more efficient than individual ones. And it makes sense to have a professional operator behind it, so that citizens aren't left to handle everything themselves.” - Astrid Birnbaum, HTF Director
By replacing traditional oil boilers with geothermal heat, the inhabitants of Vridsløsemagle saw their heating bill dramatically reduced. Now, the average yearly cost rounds DKK 11,230 (€ 1.505,46), almost a third of the average amount for oil boilers: DKK 28,904 (€ 3.874,79).
Due to its attractive prices and environmental benefits, there are now about 60 households connected to the system, and more are expected to join.
Technical Details:
Supply: 60 households with more able to join in future expansions
Total pipe length (including service lines): ~4.3 km
Pipe materials: Uninsulated PE (polyethylene)
Pipe dimensions:
280 mm diameter near the pump station
160 mm diameter on main lines
32 mm diameter on service lines
Number of boreholes: 23 vertical closed-loop
Depth per borehole: 200 meters
Total length of collector pipes in boreholes: 4.6 km
Collector pipe diameter: 40 mm
System capacity: 585 kW
Estimated peak supply requirement: 475 kW