Research into growing under solar panels

05-09-2025
In 2022, at a location of the KOB in Bavendorf, an orchard has been laid out where two types of solar panels are compared with a hail net. The solar panels have been chosen in such a way that the light interception of these panels equals the light interception of a hail net. In figures: the individual modules intercept 50% of the incident light. Because the modules do not cover the complete surface, the light interception of the total ‘roof’ is between 35 and 38%.

Half of the solar panels has been fitted like a small roof with an inclination angle of 10% over the tree rows (see photo); the other half is fitted out with panels that can turn with the sun (varying angle of inclination, see photo). In case of rain, these panels are placed in a horizontal position to protect the trees from the rain as much as possible. 

Under the panels the varieties Freya, Topaz, Natyra and Delcored have been planted. These varieties have low scab susceptibility or are scab resistant. The control block is provided with a grey hail net. 

The trees are still too young (2024 was the 3rd leaf) to be able to draw reliable conclusions on the influence of the solar panels on production and fruit size. It is possible, however, to offer a few tentative results on the basis of observations up till now:

• The differences in growth and production between varieties are big. Natyra clearly showed least growth and as a result has the lowest production.
• Under the hail nets, production is slightly higher than under the solar panels.
• The best coloured fruits are under the hail nets.
• Under the solar panels, ripening and picking date are a couple of days later.
• Under the solar panels there is less fruit rot.
• There is a negative effect of solar panels on woolly apple aphid.