The SUNSTORE2 was a project to enlarge the solar collector area of the original plant with approximately 10,000 m2 and add pit heat storage, to enable the solar collector plant to cover 30% of the town’s yearly thermal energy consumption.
The project had the following objectives and results:
The result was, that the 10,000 m3 pit heat storage in Marstal was constructed at 67 EUR/m3 and using the same prices/unit a 100,000 m3 storage can be constructed at 31 EUR/m3 (price level 2004)
The result was an efficiency improvement of 19% and a 5% higher price. Thus the cost efficiency was 13% better.
The 10,000 m3 pit heat storage was built and six different solar collectors are demonstrated.
In Marstal 8,019 m2 of new ARCON-HT collectors and 10,000 m3 pit heat storage was established for less than EUR 2.28 million. The production is around 3,800 MWh/year. If the financial costs are 6.7%/year, the heat price is 0.04 EUR/kWh. The plant has covered 28% of the total energy production in both 2007 and 2008.
After the SUNSTORE2-project, the solar plant Marstal Fjernvarme now covers the heat demand nearly 100 % in the 3 summer months. The number of clients connected to the district heating system is today 1,460 and district heating covers 95% of the heat consumption in Marstal. The SUNSTORE 4 project makes it possible to connect Ommel, a small village, with another 120 clients.