Since this summer, the greenhouse roof of microgreens grower Koppert Cress in Monster has been looking different from most of the other greenhouse roofs in the area. Director-owner Rob Baan calls it an ‘energy roof ‘.
The roof of the 2.3-ha greenhouse has been covered with 1,582 solar collectors. In the summer, the company cools its greenhouses with water from an underground geothermal system at 170m depth. The solar collectors on the ‘energy roof’ can heat the water that cools the greenhouse from 18º-23ºC to 45ºC before injecting it into the geothermal system.
Koppert Cress got special permission, through a Green Deal with the government, to pump 40ºC water back into the geothermal system instead of the standard 25ºC. The combination ‘energy roof’, geothermal system and Green Deal enables the company to cool its greenhouses efficiently in summer, while collecting and storing heat to warm the greenhouses in winter. This way, the nursery makes optimal use of its geothermal system and it will be less dependent on fossil fuels.
There aren’t any solar panels that generate electricity on the greenhouse. According to Baan, they don’t need those because they’re importing green electricity from Norway. “Considering their low prices, it doesn’t make sense for us to generate our own electricity.”