Marstal Fjernvarme

Marstal Fjernvarme is a district heating network on the island of Ærø that collects solar energy through rooftop installations to warm homes and buildings. The system stores excess heat underground during summer months and releases it during colder seasons to maintain a continuous supply to residents.

The heating network began operations in 1962 and shifted toward renewable energy starting in 1994 with solar collectors installed at a local swimming pool. This transition established the system as an early model for community-based solar heating in Denmark.

The district heating system demonstrates Danish engineering excellence through community ownership and operation by local residents of Marstal.

The system operates most effectively during sunny months when heat can be collected and stored in abundance. Visitors should know that the underground heat storage reservoirs are not directly accessible, but the concept can be understood through information displays and educational materials available at the site.

The system uses an intelligent control mechanism that adjusts pump operations based on solar radiation levels, significantly reducing energy losses in the pumping process. This automated approach makes the installation highly efficient and low-maintenance over many years of operation.

Location: Ærø Municipality

Website: https://solarmarstal.dk

GPS coordinates: 54.85229,10.50630

Latest update: December 14, 2025 18:41