Luc Janottin, a farmer in Sonchamp, France, shows me a sack of rotten cashews their producer couldn’t sell. It goes into the methane plant that he and five farmer neighbors built for about $6 million to diversify their businesses. Its giant metal domes consume 30 tons of organic material a day, mainly barley they grow as a cover crop.

“We have also started to take in more and more food-industry waste, like the pulp left over after you’ve extracted sugar from beets or insect-infested flour,” said Janottin, speaking in French.  

Large, metal biogas domes that transform agricultural waste into methane are sprouting all over the French countryside.

The barley and organic waste trucked in to Janottin’s farm are mashed up by a grinder, then turned into gas that’s piped into homes in a nearby town. The residue is used as fertilizer.  

French methane production is rising fast, said Anthony Mazzenga of the gas carrier GRTgaz.

“We already have 442 methane plants pumping gas into the network, and another 1,000 will be hooked up soon. Longer term, it would be perfectly possible to replace a third of our gas consumption with locally produced renewable gas like this,” he said, speaking in French.

What may slow things down is local resistance. Jean Lyon is president of a citizens group that’s trying to stop a biogas plant next to his village in the Vexin area, north of Paris.  

“So you move all this stuff and you let it rot for about eight to nine months. Anything rots open air is gonna stink!” Lyon said.

Janottin said he hasn’t had problems with his neighbors, perhaps in part because — to reassure them — he sited his biogas plant next to the farmhouse where he lives.