Description
This circular economy example deals with the production of biogas and biomethane at the Méthavalor plant in the Grand Est region, France.
Biogas is a sustainable gas generated using different biodegradable materials and waste, through a fermentation process called anaerobic digestion. In order to inject biogas into the natural gas grid or use it as a transport fuel, carbon dioxide is then removed. This upgraded gas is called biomethane.
Sydeme – a local syndicate for transport and treatment of household waste, manages the project and is responsible for the treatment and transport of household waste. Sydeme covers 14 inter-communalities, formed by 298 communes totalling approximately 385,000 inhabitants. Every year, 45,000 tonnes of waste are processed through anaerobic digestion and turned into biomethane, which is injected into the gas grid by GRDF (Gaz Réseau Distribution France), the main natural gas distribution network operator of the country.
Added value
The production of biomethane, electricity and heat fits into the circular economy model as waste is reused to produce biogas, which is then upgraded to biomethane quality before being injected into the grid. This biomethane is also used to fuel the fleet used for waste collection. The digestate from the production of biogas is used as fertiliser but also composted in an environmentally friendly way. The biomethane injected supplies 375 households with green gas every year.
The injection into the gas grid started in 2013. The plant size amounts to 50 Nm3. The capacity of the plant is 4.5 GWh per year. 10,000 tonnes of solid digestate are composted and 18,000 tonnes of liquid digestate are spread each year.
The activity of the plant has brought many local benefits, such as creating jobs, protecting the environment, providing sustainable energy for households and high quality fertilisers for farmers.
Challenges
- Produce simultaneously electricity, heat and biomethane ready for injection into the gas grid: to make it easier to recover different types of biowaste and produce these three outputs, the Méthavalor site has developed a unique and efficient system of waste separation by flux.
- Create a integrated circular economy system, from the collection of waste to the production of biogas and digestate used to benefit local actors and citizens.