Marcoussis solar farm: sheep, natural allies of green energy

Here, sheep are natural allies of solar panels. Unlike agrivoltaic projects, where agricultural production takes priority over energy production.

Eco-grazing has become established since 2021 on this former wasteland with a rugged profile unsuitable for mechanical mowing: 165 sheep graze in the 46-hectare enclosed park, developed by Engie and the intercommunal union of gas, electricity and new energies of Île-de-France (Sigeif).

Sheep were preferred to goats who were "too undisciplined, risking damaging the solar panels or tearing out cables with their horns", explains Sylvain Girard, president of Ecomouton, which provides the service on the site.

“Adapting the sheep”

The introduction of sheep to Marcoussis defied an unforeseen event: the presence of Spanish sainfoin, an invasive plant with flowers toxic to herbivores. “We had to adapt the sheep,” laments Pauline Duda, manager at Engie Green, operator of the site.

The Ouessant sheep was selected because it did not risk poisoning. “It is, to my knowledge, the only French breed of sheep that does not eat these flowers,” explains Sylvain Girard.

Marcoussis town hall initially planned to sell meat and wool in a short circuit. Edible but insufficiently profitable, the Ouessant sheep does not allow it. “It only yields 4,5 kg of meat, compared to 10 for a standard sheep, at the same slaughter cost,” explains Sylvain Girard.

Its wool is not commercially exploitable. It is donated and used by golf courses as a natural fertilizer. “Unfortunately, wool is considered waste. Its treatment is too expensive, 90% goes to the incinerator,” confirms Sylvain Fabiani, treasurer of the French Eco-pasture Federation.

“No simple clippers”

Ecomouton has 6.000 sheep on 450 sites in France. A quarter of the livestock is allocated to solar parks, the rest to industrial and logistics sites, prisons, nursing homes, etc. Its turnover increased by 10% in 2023, in line with the boom in the sector in France. .

Animal et Cité, which references animal professionals, listed 27 eco-grazing providers in France in 2014. It counts 350 today.

A dynamic driven by the benefits of practice. “Eco-grazing is conducive to pollinators, coprophagous insects and birds. Our sheep serve biodiversity and the environment. They are not simple lawnmowers,” says Sylvain Fabiani.

The Marcoussis land was not agricultural, the project therefore does not fall within the definition of agrivoltaism, which avoided the conflicts of use that we see arising here and there, and which the law has recently tried to eliminate. channel.

“Bring synergies”

“Agrivoltaïsm is above all an agricultural tool. We must identify relevant projects in which energy provides synergies,” underlines Stéphanie-Anne Pinet, general delegate of France Agrivoltaïsme, an association bringing together players in the sector.

For example, “feedback confirms the protective effect of photovoltaic panels against hazards such as frost, hail, drought and heat waves,” assures Ms. Pinet.

The installation of solar panels is relevant for livestock farming in meadows, with summer shade helping the animals. Conversely, less light degrades cereal production.

The National Research Institute for Agriculture, Food and the Environment (INRAE) is assessing the impact on livestock meadows.

"The results are mixed. The growth of the grass changes little but its composition is modified. The species present under the panels evolve and the plant cover degrades", notes Catherine Picon-Cochard, research director at Inrae.

To dispel controversies, the 2023 renewable energy acceleration law regulates practices. Solar panels cannot lead to a reduction in agricultural production. And each project must provide at least one of the following four benefits: improved yield, adaptation to climate change, protection against hazards or improved animal welfare.

So many requirements for “developing projects that meet both the challenges of food and energy sovereignty”, according to Stéphanie-Anne Pinet.