The solar thermal park in Dorkwerd has been officially opened by René Paas, Commissioner of the King. It is the largest solar thermal park in the Netherlands.
Solar thermal energy is a method of storing solar energy in hot water. When the sun shines, the collectors capture sunlight and convert it into heat. This sustainable heat is stored in a buffer tank and then fed into the heat network.
A heat network is an underground pipe network that transports heat to buildings and homes via hot water. It heats homes and buildings and supplies hot water for showers, for example. A heat network thus provides an alternative to using gas to heat buildings, among other things.
Operational since the end of 2024
Dorkwerd is a project realised by developers Novar, K3 and technology partner TVP Solar. They are working together with Groningen municipality's public heat company WarmteStad and Waterbedrijf Groningen. Although officially opened this week, the solar thermal park will be operational by December 2024, supplying heat to WarmteStad's heat network.
The realisation of the solar thermal park was chosen after it became clear at the start of WarmteStad that ground heat was not an option due to the region's sensitivity to earthquakes. Alternative techniques were therefore sought, so solar thermal was eventually chosen.
Sustainable heat for 2,600 households
The solar thermal park will provide 2,600 households in Groningen with sustainable heat. It provides a peak annual capacity of 37 MWth.
The park has been realised on a former dredging depot owned by K3, whose activities include the extraction of sand, gravel and clay. The depot has a total area of 22 hectares. Of this, 12 hectares are earmarked for the solar thermal plant, while the remaining 10 hectares have been set up as a nature reserve.
24,000 solar collectors
The park contains 24,000 advanced solar collectors, supplied by TVP Solar. Thanks to a unique vacuum technology, these collectors convert sunlight into heat extremely efficiently, even on cloudy days or in winter. The panels heat water to around 95°C, which is piped to a buffer tank on the site.
The solar collectors differ from regular solar collectors. Whereas 'regular' collectors generate electricity, the solar collectors in Dorkwerd actually generate heat. Instead of cables, water runs along the solar collectors. This water heats up to about 95 degrees Celsius on a sunny day. A special vacuum technology in the collectors makes it possible to efficiently produce high temperatures.
Buffer tank of 6,000 m³
The parties first temporarily store the generated solar heat in a 6,000 m³ buffer tank on the site of the solar thermal park. This buffer tank enables flexible response to daily heat demand.
However, the biggest challenge lies in the seasonal differences. For instance, a lot of heat is produced in summer, while demand is high in winter. For this reason, an underground seasonal storage facility has been built at the Zernike WarmteCentrale. The storage uses an underground heat source at a depth of about 175 metres, in which up to 230 million litres of hot water can be stored.
In summer, the parties store excess heat in the underground. This is then pumped up again in winter. In this way, the heat is available at times of high demand but low sun and therefore production.
