The greenhouse industry has traditionally used natural gas for heating. However, this production method results in high greenhouse gas emissions. By switching to electric lighting in the greenhouses, the industry faces a possibility to a more climate friendly method of operation.
Fruit and vegetables produced in Norway account for around 35–40% of the products on sale in shops. There is potential to increase the Norwegian production significantly, especially in the greenhouse sector.
The traditional use of natural gas for heating result in high CO2 emission. Researchers at NIBIO have helped to develop new operating methods involving a switch from heat to light, 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.
Light, and not heat, is the limiting factor for plant production. A new cultivation system, developed at NIBIO, increased tomato production from 40 kg to 120 kg by using supplemental light. In addition, CO2 emissions were reduced by 60% and energy consumption by 40% per kg of tomatoes.
Switching to electric lighting is expensive, considering the current high electricity prices. However, calculations performed by NIBIO have shown that investing in LED lighting can pay off.
Recently, NIBIO tested a new system that controls and regulates heat, humidity and CO2 level in a greenhouse with supplemental lighting. This system increased production while windows were kept closed. Combined with a facility that captures CO2 from outdoor air, CO2 emissions from tomato production were reduced to zero.