Courgeon, Messei, Sées, Saint-Mars-d’Egrenne, Saint-Quentin-les-Chardonnets, Valframbert… In the four corners of Orne, domes flourish in the countryside. In recent years, methanization projects, the production of gas from organic materials, including agricultural waste, have multiplied. Bigger, more powerful, methane digesters have conquered the agricultural sector and its wallets.
In Saint-Symphorien-des-Bruyères, northeast of Orne, three domes are visible within a radius of ten kilometers. Fourteen farmers started the Agrimethane site in Ouche in 2022, after twelve years of reflection. “We ensure gas production for 3,700 homes all year round”presents Christophe Mesenge, farmer and member of the collective.
The example of gas distributed at L’Aigle
Every day, the materials pass through a crusher then into the three digesters. “We can inject up to 130 tonnes of materials per day, describes Flora Rouillé, co-responsible for the site. Effluents (agricultural waste) represent 60% of what is injected. The rest is corn, intermediate energy crops and external materials such as milk unfit for consumption and unsold food. »
This input tank is heated to 50°C for eighty days in the three digesters to dissolve the bacteria. At the outlet: biogas. Well, almost. “We have around 55% biogas, explains Christophe Mesenge. The last digester removes the 45% of carbon dioxide in the methane. »
The gas is then sent to a transformer, where it is purified. “It finally goes into a GRDF pipeline and is distributed to L’Aigle and the surrounding area. Since we had a countdown (installation which connects gas networks between several territories)we can export it to the Paris region”, develops the farmer. All production is controlled on computers. In the event of surplus production, the methanizer can send its gas to another network thanks to reverse flow. And in the event of a malfunction, a system interrupts the process.
L’Orne,…
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