How to attain emission free greenhouses

Fruit and vegetables produced in Norway account for around 35–40 per cent of the selection of produce on sale in shops. There is enormous potential to increase the Norwegian production significantly, especially in the greenhouse sector.

The traditional use of natural gas for heating produces high levels of CO₂ emissions. Researchers at NIBIO have helped to develop new operating methods involving a switch from heat to light. This is the most effective measure to reduce greenhouse gas emissions in the greenhouse industry.

“A greenhouse is a solar collector that captures twice as much energy as it uses in a year. By closing the air vents and accumulating the heat in a water tank, we collect the heat during the day for use at night. Our calculations have shown that this will reduce the energy consumption of heating by 50 per cent,” explains NIBIO researcher Michel Verheul.

In greenhouse production it is light, not heat, that is the limiting factor for production. A new cultivation system at NIBIO has shown that tomato production increased from 40 kg to 120 kg by installing lighting. In addition, CO₂ emissions were reduced by 60 per cent and energy consumption by 40 per cent per kg of tomatoes. 

Switching to electric lighting could be very costly, especially considering the current high electricity prices. However, calculations performed by NIBIO have shown that investing in LED lighting can pay off.

NIBIO has also tested a new cultivation system using lighting that regulates heat, humidity and CO₂ level in the greenhouse. The system was combined with a facility that captures CO₂ from outdoor air.

The results showed that the CO₂ emissions from tomato production were reduced all the way down to 0.