Farm-produced green gas

Posted on 08 July 2015.

Organic waste is converted into biogas and fertilizer by anaerobic digestion. This process, which has won over the agricultural sector, also appeals to towns.

An economic alternative to the rising cost of fossil fuels – when used as a fuel biomethane emits very little CO2 and no fine particles.

Peggy will have to swap her pot of milk for a tank. Because it won’t be milk she’ll be selling in the market town but biogas. For example in Mortagne-sur-Sevre in the Vendée. Centrally positioned between four farms raising calves, cows, ducks and pigs are two gleaming domes. They house a farm-based biogas plant: AgriBioMéthane. Every year 21 metric tons of slurry, manure and animal fat from slaughterhouses in the area are converted into biomethane and fed back into the distribution network of Gaz de France (GrDF).

Purified biogas becomes biomethane and town gas

Biogas production has not surprisingly won over the agricultural sector. By recycling otherwise unused waste, it produces not only biogas but also fertilizer - the residue from the process. This renewable energy can be used to produce both electricity and heat. But once purified – removing for example the CO2 and oxygen it contains from the natural gas - it becomes biomethane, which can then be sent into piped gas networks. The idea of producing biogas also appeals to local authorities because it offers an environmentally friendly solution to reducing waste.

Biogas for 4000 people

The proof: Le Plessis-Gassot in the Val-d'Oise area is now home to the Electr'od power station, the largest unit in France producing electricity and heat from non-recyclable waste. For the first time ever a town is using biogas in a brand new heating and hot water system - and to top off the benefits, it reduces residents’ energy bills by over 90%! And in south west France the first industrial biogas plant has just been opened, the Grand Auch biogas plant. It recycles up to 40,000 metric tons per year of waste from agriculture, food processing industries and local authorities for a biogas production equivalent to the consumption of 4,000 people. By 2030, the gas system could contain as much as 10% biomethane - and gradually help to make France more energy independent. And in addition to being clean and renewable, biogas is a local energy source and so part of a circular economy.