PlanEnergi has been consultant to the plant owner, Marstal District Heating, since 1995. The first project was 8,000 m2 of solar thermal collectors in 1995-96. These were expanded to 18,300 m2 in 2002-04, along with a 10,000 m3 pit heat storage. In the SUNSTORE 4 project, the final steps towards a 100 % RES-district heating system were taken by extending the system with:
- 15,000 m2 of solar thermal collectors
- 75,000 m3 pit heat storage
- 0,5 MW (cooling) heat pump
- 4 MW wood chips boiler, with a 750 kWel ORC (Organic Rankine Cycle)
The system came into use in the summer of 2012, making it the world’s second largest solar district heating system at the time. The project received funding from the 7th Framework Program of the EU.