Chagny: the circular economy on a local scale

Methanisation fits in perfectly with the transition to a more energy-efficient and ecological world. Locally produced biomethane enables greenhouse gas emissions to be cut, waste to be recycled and imports of natural gas to be reduced. It also enables a region to diversify its energy mix, create jobs and revenues that are anchored in the local community and build synergies between local businesses.

Biomethane creates a virtuous circle, allowing locally generated waste to be recycled into renewable low-carbon energy. The growth outlook for this technology is substantial: the Energy Transition for Green Growth Act of 17 August 2015 sets a target of generating 10% of France's gas consumption by 2030. Concrete projects such as the one at Chagny contribute towards meeting this nationwide target.

The biomethane life cycle at Chagny

Trucks collect the household waste of around half the households in the département of Saône-et-Loire – over 300,000 people, producing an average of 73,000 tonnes of waste each year.

This waste is brought to the ECOCEA site, which is home to a mechanical biological treatment plant. Organic waste is separated from the plastics, metals and other waste materials for fermentation.

After the sorting process, the organic waste is placed in a methaniser, enabling biogas to be obtained via an anaerobic digestion process. The solid residue from this process, known as the "digestate", is mixed with green waste and used as compost.

The biogas is made up of methane, carbon dioxide and hydrogen sulphide. Once obtained, it is then refined using membrane filters to produce methane. Methane produced in this way is referred to as "biomethane".

SMET 71 injects the compressed methane into the gas supply grid operated by GRTgaz at an injection station close to the ECOCEA site. The GRTgaz station enables the quantity of biomethane to be measured, allows its composition to be checked and odorises it so that it can be mixed in with natural gas. Biomethane has the same properties as natural gas.

TERREAL's plant is directly linked to the GRTgaz grid. Gas from the grid (biomethane plus natural gas) is used to operate the kilns and make terracotta roofing tiles.