“Plants need heat, light, CO2, water, and nutrients,” explains Michel Verheul. “In Norway, there is a general problem of too little light, so we have long-term experience with artificial lighting. Traditionally, Norwegian growers have been using sodium lamps. We found that switching to LED lighting could cut energy use for lighting by 40%. However, at some point the extra light didn’t improve yields.”
The scientists found that the limiting factor was CO2. The plants need CO2, but in a traditional greenhouse this greenhouse gas is – almost ironically - lost to the outside air. This does no good to the atmosphere while the greenhouse plants are deprived of this vital growth factor.
“Hence we came up with the idea to close the greenhouse. We got in touch with the company GreenCap Solutions which has invented a very interesting system of CO2 capture.”
While most other direct carbon capture systems use hazardous chemicals to extract CO2 from the air, this system does not. Instead, it employs a natural zeolite mineral with no chemical footprint, explains Verheul. Due to its unique properties, zeolite allows dynamic short-term capture and release of CO2 to a closed greenhouse. This enables micro-management of CO2 levels in the greenhouse.