Optimization of light, energy and water use efficiencies in an improved Venlo greenhouse

The amount of light received during winter in the Netherlands is a limiting factor in the development of greenhouse protected crops. Obtaining good yields in this period would suppose a greater economic profitability for the growers, because the horticultural products have a greater economic value in the market in this period. As a possible solution, researchers from Wageningen University & Research (WUR) Business Unit Greenhouse Horticulture, together with a consortium of greenhouse suppliers, designed and built a new improved Venlo greenhouse called "Winter light" (WL), with the purpose of increasing the amount of solar light inside the greenhouse with the focus on the winter months when light is the limiting production factor. The objective of this study was to compare the WL with a conventional Venlo greenhouse, both with cucumber cultivation (Cucumis sativus L.), to determine its hypothetical advantage in the efficiency of the use of inputs of light, water and energy. For this, 2.5 cultivation cycles were carried out from December 2016 until May 2019 in the experimental centre of WUR Greenhouse Horticulture at the location of Bleiswijk (WL) and in a conventional greenhouse of a local producer located in the municipality of Berkel en Rodenrijs (REF). The results showed increases in the WL efficiencies compared to REF greenhouse of 47% for heating, 15% for the efficiency in the use of radiation by the crop, and 6% in the efficiency in the use of water. In addition, a simulation was carried out to investigate the energy input in artificial light necessary in the REF greenhouse to reach the same level of production in both greenhouses. It was possible to conclude that the set of improvements applied together with a correct management of microclimate, cultivation and crop care make the WL a more efficient greenhouse for all the studied input.