Abstract :
[en] The Grewfarm project is a photovoltaic greenhouse development initiative in the Walloon Region, supported by three competitiveness clusters (Wagralim, MecaTech, GreenWin) and led by a consortium bringing together academic research institutions (UMons, ULiège, HEPH Condorcet) and private companies (Green Energy 4 Seasons, DHK).
The main objectives are: (i) to develop an innovative range of photovoltaic greenhouses, (ii) to design production auxiliaries controlled by new software, and (iii) to develop services for the study and implementation of agrivoltaic projects.
ULiege and HEPH Condorcet are responsible for assessing the agronomic performance of these greenhouses based on the shading rate generated by the installation of solar panels on the roof. The production of a variety of vegetable crops - both summer and winter, as well as mid-season crops - will be monitored over two years at two sites: Ath (BE-7800) and Gembloux (BE-5030). A pilot photovoltaic greenhouse has been installed at each site, with two levels of solar panel coverage: 30% (moderate coverage) and 50% (high coverage). Additionally, the Gembloux site includes an open-field plot, while the Ath site has a conventional tunnel greenhouse.
Results from the first year of monitoring indicate a reduction in photosynthetically active radiation (PAR), measured as daily light integral (DLI), of approximately 30%, 50%, and 60% under the conventional tunnel greenhouse, and the zones with moderate and high solar panel coverage, respectively, compared to an open-field plot.
For the summer crops tested in 2024, average production decreases of approximately 23% were observed between the zone with moderate and high solar panel coverage. More specifically, for certain crops (cucumbers, tomatoes, peppers, strawberries), yield reductions compared to a reference tunnel greenhouse averaged 28.5% and 44.4% in the photovoltaic greenhouse under moderate and high coverage conditions, respectively.
Those observation need to be continued in 2025. In the long term, the collected data on crop production will be compared with the solar energy production of the photovoltaic greenhouse to determine the optimal solar panel coverage rates that enable vegetable production and energy generation within the same space.
