In the shadow of solar panels

Combining food production and energy production: that's the challenge of agrivoltaics. A concept born in Montpellier that has since spread all over the world: installing solar panels on agricultural plots. Christian Dupraz, researcher at the Absys laboratory laboratory, the man behind the idea.

100 gigawatts of photovoltaic energy by 2050 - that's the target announced by the French President in February 2023. " It's a tall order: south-facing roofs, parking lots and brownfield sites won't be enough to meet this ambitious but necessary target," says Christian Dupraz. For the agroforestry researcher, the solution can be summed up in one word: agrivoltaics.

Agrivoltaics means combining photovoltaic panels and agricultural crops on the same plots of land. " The concept was born in Montpellier in 2009, with the world's very first prototype installed in Lavalette," recalls Christian Dupraz, the man behind the project. "When you look at the light output of an agricultural plot, you see that crops only use a third of the sun's rays. The remaining two-thirds, which is not used for agricultural production, can be used to generate photovoltaic energy, so the process makes better use of the sun", explains the crop modeler.

Mobile panels

And to ensure that crops get their fair share of sunlight, there are two options: either install panels at a reduced density on the plot, "or use mobile panels that can be moved aside to let light through to the crops when they need it", explains the Absys laboratory researcher. A well-designed agrivoltaic power plant can therefore fully maintain agricultural yields, and sometimes even improve production by protecting crops against climatic excesses.

"The panels protect the soil and crops from excessive sunlight, which reduces their water requirements by 20% to 30% and represents a significant saving in irrigation costs. They also limit the risk of crop scorching in the event of heatwaves, while protecting them from hail and tempering the effects of frost", explains the researcher, who points out that the crops protected by the panels can be of any type: market gardening, fruit trees, cereals, etc. "But also for vines, which have suffered in recent years from a lack of sunlight. But also for vines, which in recent years have suffered from excessive sunshine, which makes the grapes too sweet and reduces wine quality. Several winegrowers have installed agrivoltaic power plants and are very satisfied.

Cheaper electricity

And the electricity generated in this way can either be sold back to the grid, or used for self-consumption. There is growing interest in this technology, especially as photovoltaics has recently become the cheapest form of electricity," points out Christian Dupraz. We have calculated that by equipping less than 2% of France's cultivated area with new-generation agrivoltaic systems, we can produce the electricity equivalent of all our current nuclear power plants, without any reduction in agricultural production". With an agrivoltaic power plant inaugurated every two months in France, the idea is catching on.