Which two crops can be grown energy efficient together?

Which combination of two crops in a greenhouse can be grown fossil-free and with less than 100 kWh/m2 of energy per year? The Kas als Energiebron innovation program posed this question to the Greenhouse Horticulture and Flower Bulbs Business Unit of Wageningen University & Research. That maximum appears to be achievable with a combination of seven months of sweet peppers and 4,5 months of green potted plants. Researcher Arca Kromwijk (WUR): “It is very interesting to start with energy availability and look at suitable combinations of different crops from there.”