For 18 months, technicians from the Fontenet photovoltaic park have been crossing the 650 Charollais sheep of shepherd Judickaël Richard, 50 years old, breeder in Saint-Loup (Charente-Maritime). Operated by the German BayWa re, this 81 hectare site is located on the former air base 129 Saint-Jean-d'Angély-Fontenet. Since 2019, sheep have been used to maintain it and replace mechanical mowers. The shepherd is paid for this, 38,000 euros per year.
“This allowed me to increase the herd and allows me to pay myself a salary. Without Fontenet, I would have stopped this activity”explains the breeder, who is bearing the brunt of the drop in meat prices even though he sells through a short circuit. The latter also noticed that, since his sheep grazed in the shade of the panels, they reproduced more. On average, they went from “1.3 to 1.4 lambs per year to 1.7 -1.8 lambs per year”specifies the breeder. The reasons for this are not very clear. But the R&D program of the National Research Institute for Agriculture, Food and the Environment (INRAE) provides first clues.
A more digestible herb
Regularly, Amélie Stepec, an engineer from the institute, comes to the park to carry out surveys on the plants growing there, under the panels, in the inter-rows and in a control area, where meteorological sensors have also been installed since 2020. The Fontenet park participates, with two other solar sites located in Allier and Aude, in the Solar research program (Optimization Solutions and Levers for agrivoltaism) managed by the new National Research Center on Agrivoltaism (PNR agriPV).
On the three parks of the Solar program, Amélie Stepec has already been able to observe under the panels a drop of 3 to 4°C in the ground temperature, an increase of up to 11% in soil humidity and a lower forage quality. improved. Ultimately, there is a greater proportion of nitrogen and minerals, making their feed more digestible for the sheep. These first results were presented on June 11 at the agricVoltaics conference in Denver in the United States, but they are only provisional. “The panels create a microclimate, explains Théo Girardin, research engineer at the PNR AgriPV at Inrae. But depending on the year, it will have a positive or negative impact on yields and forage quality. You need to have data over 4 to 5 years”.
-Results which remain provisional
Even provisional, these results are also useful to BayWa re, which will have to provide data on its projects to Ademe, which is responsible for evaluating agrivoltaic technologies. They will also allow it to better size its new AGRiPV projects so that they respect the three main criteria of the decree published in April 2024: 10% maximum loss of agricultural area, 40% maximum rate of soil coverage by panels and 90% guaranteed return. Which today is difficult to guarantee a priori.
