"When lettuce is grown in closed climate chambers, the risk of crop failure is reduced." This is the opinion of researcher Jeroen van Roy, following research he is conducting for the Energy Knowledge Centre (KCE) of Thomas More University of Applied Sciences. Within KCE, he is mainly concerned with greenhouse horticulture and climate chambers and tries to make the latter more sustainable so that more growers can make use of them.
"If you want to grow in a greenhouse for a whole year, you need extra light, because in winter there is not enough sun to keep production optimal. That is why we are researching how we can gradually change the amount of light because plants prefer a constant climate. We ensure this by intelligently controlling the lighting: on very sunny days we illuminate less and on dark days more. The aim is to save energy without affecting crop production. This system is called light integration. We then look into how we can make the best possible use of additional lights. For instance, when does it still make sense to add light and what does the extra light do for the plant at that moment?
Striving for energy-efficient greenhouse horticulture
"What surprised me at first was how much is already being done in greenhouse horticulture to make production as energy-efficient as possible. I think it's a shame that this is rarely mentioned in the media. For example, many companies work with a Combined Heat and Power installation. This is an installation that generates both electricity and heat. The electricity can then be used to light the greenhouse or put it on the grid, and the heat is used to heat the greenhouse. A system like this usually starts from natural gas that is burned and that produces flue gases. These flue gases contain CO2, which the plants absorb as a nutrient."
Growing lettuce without sunshine
"Apart from generating energy, the energy story is also about controlling the climate. You can do that well in greenhouses, but you have even more control over all the factors in climate chambers. In climate chambers, we grow crops without sunlight in a closed room. All crops have different needs: lettuce, for example, needs a cool night. You can perfectly control these needs in such a climate chamber because there is no sunlight. When everything is in order, the big advantage is that there is less chance of pests, diseases, and crop failure. In Flanders, this is not yet done on a large scale because there is still some work to be done to make the chambers more sustainable, but we are working on that now."
Source: Thomas More