- Install photovoltaic panels above the crops. High enough for tractors to pass underneath. This is the whole principle of agrivoltaism, one of the tracks of the ecological transition.
- It has the advantage of killing two birds with one stone, by reconciling electricity production and cultivation on the same plot. A great asset in the fight against artificialisation of soils.
- But Antoine Nogier, president of Sun'Agri and Christian Dupraz, researcher at Inrae, also see in these solar panels above the fields a precious help for agriculture where it is already grappling with global warming.
"In the past, we planted apricot trees between the vines, every three or four rows," recalls Pierre Escudié. He talks about the time when his grandparents, then his parents, took care of the Domaine des Nidolières, the wine estate in the hands of the family for eight generations, in Tresserre, near Perpignan. “At the time, the idea was much more to have two crops, and thus an additional income, than to shade the vines and thus protect them from the heat. "
The apricot trees have disappeared. “It is complicated, from an administrative point of view, to have two crops on the same plot, says the 69-year-old winemaker. And then these trees have the disadvantage of competing with the vine by drawing from the soil their share of water and nitrogen. On the other hand, the sun is still beating just as hard in Tressere. More than before, to listen to Pierre Escudié. “When we reached 33 ° C, it was exceptional. We reach 34, 35 or even 36 ° C almost every summer, ”he explains.
Solar panels instead of apricot trees
It is the haunt of the winemaker. "The risk, in hot weather, is that the grapes ripen too quickly, from August, and are too loaded with sugar, explains Christian Dupraz, researcher in agroforestry at the National Research Institute for Agriculture, food and the environment (Inrae). It makes alcohol, of course, but not good wine. "
Far in any case from what Pierre Escudié wants to do. So the winemaker took the lead. Not by replanting apricot trees between its vines, but by saying “banco” to Sun'Agri. Since 2009, the company has been working on the development of a system of photovoltaic panels to be installed above crops. High enough for tractors to pass underneath. Sufficiently removable, too, so that the panels can sometimes let in the light that crops need, sometimes provide shade or protect them from heavy rain, frost and excess weather.
A win-win called "agrivoltaism"
"It is the same principle as the louver in your office, compares Antoine Nogier, founding president of Sun'Agri. At times, you are happy that it lets the sun through, and at other times, that it shades you. This is exactly what we do with our solar panels, remotely controlled by an algorithm that takes into account many parameters to constantly maximize the well-being of the plant. "
This win-win - electricity production and crop protection - has a name: agrivoltaism. At Nidolères, it is still difficult to get an idea of its contribution. The agrivoltaic power plant, inaugurated in November 2018, covers 4.5 hectares of land, out of the 50 that make up the estate. Above all, under the panels, no mature vines yet, but young plants for which the winemaker hopes for a first harvest next year. "We can already say that, under the panels, the vines grow as well as on the control plot," says Pierre Escudié, with a smile.
A first world congress, in October, in Perpignan
Christian Dupraz invites in any case to retain this idea. "Agrivoltaism is an important avenue of research and development for the ecological transition", he insists. The researcher wants as proof the first world congress which will be dedicated to him, in October in Perpignan, and of which he will chair the scientific committee. Nearly 300 researchers from 27 countries are expected to participate. "For ten years, projects have spread everywhere," notes Christian Dupraz. In the Po plain, the Italians of Remtec have already installed large-scale agrivoltaïc power plants above cereal crops. "
What about France? It is not lagging behind, continues the agronomist, who talks about fifty agrivoltaism projects recently identified by the working group in which he participates with people from the Environment and Environmental Management Agency. energy (Ademe). “Everyone is interested in it. Large operators, such as Total, but also regions, Occitania relying heavily on agrivoltaism in its energy transition scheme to become a positive energy region by 2050. ”
Fighting against snacking on agricultural land
To explain this craze, Antoine Nogier begins by talking about the fight against the artificialisation of soils, a real issue all around the Mediterranean, where the CEO of Sun'Agri prioritizes his solution. In these sun-drenched regions, "there is a lot of pressure from some energy companies to buy up farmland and transform it into a solar power plant on the ground," he begins. Even if the rules have hardened in recent years to prevent this, many players remain on the lookout and seek to pre-empt land in the hope that one day the regulations will soften. However, the maintenance of this agricultural land is vital, all the more knowing that it will be necessary to feed 10 billion inhabitants in 2050 and that the yields of the areas today exploited stagnate, or even decrease. "
This is the whole promise of agrivoltaism. It is not only a question of reconciling electricity production and agriculture on the same surface, but of bringing a real boost to plants, thanks to solar panels in regions which are already taking a heavy toll on global warming. "This applies to the vines, but also to a good number of market gardening and tree crops," says Antoine Nogier. In particular those linked to a terroir, which one cannot really move from a region without losing their identity ”.
An asset for cultures?
And the goal of photovoltaic panels "is not only to improve yields, says Antoine Nogier. It is also to produce by consuming less water, since the shade of the panels prevents, during hot weather, that the plant is subjected to a strong stress which makes it spend more energy and therefore consume more water. It is still to improve the quality of production, by better controlling the arrival of sugars in the grape, for example, for wine. "
And then there are the Ice Saints, these famous drops in temperature that occur in May to sometimes cause frosts. "But the buds, which are very sensitive to it, come out earlier than before, often now before the Ice Saints," explains Christian Dupraz. Here again, by placing the solar panels horizontally, we can avoid freezing below and thus limit breakage. "
The INRAE researcher does not promise a miracle with agrivoltaism, however. Everything will depend on the weather. "Some years, these solar panels above the fields will be a valuable asset for crops, others, very little, if at all," he says.
"Always give priority to the plant"
The other difficulty of agrivoltaism is to find this balance between sufficient electricity production for the panels to be profitable and the well-being of the plant, which must remain the number one criterion, insist both Christian Dupraz and Antoine Nogier. "This implies providing greater spacing between the rows of photovoltaic panels than for a ground-based plant, and accepting that they do not always follow the inclination of the sun, which would have made it possible to optimize the production of electricity ”, explains Antoine Nogier. Thus, at the Domaine des Nidolères, the agrivoltaic power plant reaches 2.1 megawatts of installed power. “It is much more than a photovoltaic installation on the roof of an agricultural shed, but it remains low compared to a ground power plant. "
Research suggests hope that one day we can do better. "Chinese researchers are working, for example, on photovoltaic panels which would allow useful light to pass through to plants, while others are working on bi-facial panels, which would use light on both sides", enthuses Christian Dupraz. This is already a subject of discussion for this first world congress of agrivoltaism.
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What economic model for agrivoltaism?
He is still looking for himself. One thing is certain: the initial investment is not negligible. "A system like the one we installed in Tresserre costs around half a million euros per hectare in initial investment and is only profitable after a certain time," says Antoine Nogier.
A sum payable by the farmer? Not necessarily. "We must favor systems where the farmer is the main or even sole investor, but we know very well that few of them have the capacity and the desire to invest such sums on such projects", continues Antoine Nogier.
In the economic model favored by Sun'Agri, one or more investors can intervene alongside the farmer, through an ad hoc company which will own the agrivoltaic power station installed on the farmer's land. This company is remunerated with the electricity produced, the farmer, he benefits from the contributions of photovoltaic panels on his crops, and benefits from electrical revenues through his participation in the capital of the ad hoc company .
And what about Sun'Agri? “In the long term, we would like to focus on piloting photovoltaic panels, our trademark, and position ourselves as a trusted third party between the farmer and the energy company,” explains Antoine Nogier. In other words, the one who ensures that the well-being of the plant is always the number one criterion in the management of photovoltaic panels. "
- Global warming
- Energetic transition
- Solar panels
- Weather
- Agriculture
- Planet