Technology | The greenhouse as a source of energy, Koppert Cress

Koppert Cress wants to lead the way in reducing CO2 emissions.

Reducing CO2 emissions

The horticultural sector still uses a lot of gas to produce food. As a result of the climate agreement, the horticultural sector is further compelled to heat greenhouses using other, more sustainable methods. Koppert Cress wants to lead the way in reducing CO2 emissions. An important solution that we use here for this purpose is thermal energy storage.

Thermal energy storage

To manage the climate in the greenhouse, we either add heat or we remove heat, i.e. cool it. This heat and cold are stored in underground sand layers to a depth of around 170 metres. We use the cold from the ground to cool the greenhouse. The excess heat in the greenhouse, caused by solar radiation, is removed and stored. We also capture other heat via solar thermal collectors; residual heat from light fittings; cold stores and offices; and thermal energy from surface water. We use the stored heat to heat the greenhouse again in winter. According to provincial regulations, you may only store water up to 25°C in the ground. However, thanks to a Green Deal with the Dutch government, we are permitted to store water with a temperature of 40°C. This means that the same amount of stored water can contain much more energy, which makes the system considerably more efficient. The storage temperature is also closer to the temperature at which the energy is used, which means we don't need to use the heat pump as much.

Solar thermal collectors

Solar thermal collectors have been installed on the company roof to provide additional heat capacity. These heat the colder return water from the greenhouse to 45°C before it enters the thermal energy storage system. This unique system of solar thermal collectors has been developed especially for this application and scale. Thanks to the competitive prices with which Koppert Cress can purchase green electricity, it is more cost-effective to use the roof to collect solar energy than it is to use it to generate electricity.

The greenhouse as a source of energy

Houses have been built in the vicinity of the company in recent years. These houses form an integral part of Koppert Cress’ energy management system and are now heated by the thermal energy storage system. These types of developments help the horticultural sector evolve from being an ‘energy guzzler’ to being an energy supplier. The total area belonging to Koppert Cress has more than tripled over the last decade. Nevertheless, there has been a reduction in gas consumption during this period. This can mainly be attributed to use of the thermal energy storage system. Within a few years, Koppert Cress will be connected to a cooperative heating grid for geothermal energy, which will enable the company to reduce its gas consumption right down to zero.