Par
Coralie Maux-Renard
Published on
Nov. 24, 2024 at 7:00 a.m.
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Since November 4, 2024 and until Monday December 2, residents of Capelle-les-Grands (Eure) and surrounding areas* can come consult the file “extension” of the methanizer of the Duclos family in their town hall. A term somewhat poorly chosen by state services.
No expansion of buildings
In fact, the methanizer operating since September 2023 is not going to get bigger, but increase its gas production.
“It’s a error in titlethe capacity was planned from the start in the building permit, the tanks are already present, that changes nothing,” indicates Laurent Duclosco-manager of the site with his brother Richard and his son Baptiste.
For a little over a year, the family could only produce two thirds of its capacity. To be able to create an additional third, the file passed through the hands of different State services (Departmental Directorate of Territories and the Sea, Regional Directorate of the Environment, Planning and Housing, etc.) and then was subject to public consultation.
A 30% increase
From next January, the methanizer should move to 100% capacity. For the moment, the site produces 150 m3 (n)** and will rise to 190 m3 (n) per hour in 2025. For now, the site produces gas for 6,000 homes and later 8,000.
This is the equivalent of a farm of 350 cows.
The gas from Capelle-les-Grands, and in the other methanizers in the region, makes it possible topower the entire intercom from Bernay, to Serquigny and Nassandres. “Our gas powers theArkema factory. The intercom will be completely energy independent before 2030,” indicates Laurent Duclos.
The increase in capacity will make it possible to “send gas to Paris”.
The project of a lifetime
Laurent Duclos, his brother Richard and his son Baptiste, owning a farm of dairy cows and fields of cultivation, decided since 2020 to embark on this methanizer project.
“We thought about it carefully for three years before laying the first stone,” underlines Laurent Duclos. Rather than turning to a model changing gas into electricity, the family preferred a device that can directly recover gas and supply homes in the area.
“We wanted blend into the background », he says, pointing to the vats as green as the hedges and the roof as gray as the Norman sky. “We want to stay on good terms with our neighbors,” smiles Baptiste Duclos, co-manager.
To be as compatible as possible with other local residents, the owners chose a model of methanizer that emits as little odor as possible and have it installed far from homes. “Our goal was to be 500 m from all houses », Indicates the manager.
Namely that the law provides for a minimum distance of 100 m. “We live closest, it’s a guarantee for the neighbors that they won’t cause any nuisance,” assures the owner.
As food mainly comes from rye and corn crops surrounding fields, the family will build a road on their plot. “We make sure to facilitate circulation », describes Baptiste Duclos.
The managers try to clean the road as soon as they get it dirty and adapt their schedules to avoid tractor passages during the day.
Once all the materials have been transformed (see insert), the digestatea liquid resembling compost, is used in the fields. “It’s a circular economywe have cultures that work 100% digestate », explains the co-manager whose fertilizer bills have been divided by three.
How does the methanizer work?
The Duclos methanizer is fueled mainly by plants, such as rye. This intermediate crop is harvested. The stems are kept to feed the methanizer. The 60 hectares of beets are planted, then transformed into sugar. “We recover 3,000 tonnes of pulp which also goes to the methanizer,” says Laurent Duclos, co-manager of the site. Cow slurry and corn complete the methanizer. The Sdomode (Household Waste Destruction Union in the west of the Department of Eure) also contributes to feeding the system by supplying food leftovers from canteens, transformed into “waste soup”.
External waste is first sterilized so that no pathogenic element remains at the end in the digestate spread on the plots. Every hour, the methanizer is supplied with a ton of “fuel”. “It’s like the artificial stomach of a cow,” image Baptiste Duclos, co-manager of the site. It takes nearly 120 days for solid plants to transform into gas and liquid (digestate). In a large tank, the digester, the organic matter is heated to 40 degrees so that the bacteria “have an ideal environment”. The gas bubbles emerge and rise into the tarpaulin. The gas snakes underground to drop in temperature, then gets rid of CO2, water and sulfur. A crucial step to have quality gas.
The gas is transported by GRDF and purchased by Engie.
For the moment, the methanizer injects only methane into the GRDF (Gaz Réseaux Distribution France) network. THE CO2 is rejected in the atmosphere. Later, the family wishes to add a unit for recover the dioxide of carbon, which can be sold to sparkling drink brands.
* Cordebugle, La Chapelle-Hareng, La Haye-Saint-Sylvestre, Le Planquay, Plainville, Saint-Aubin-du-Thenney, Saint-Germain-la-Campagne, Saint-Mards-de-Fresne, Saint-Victor-de- Chrétienville and Valailles.** The normo cubic meter is a unit of measurement of the quantity of gas corresponding to the content of a volume of one cubic meter, for a gas being under normal conditions of temperature and pressure.
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