Bio-gas is produced by the fermentation of organic matter in the absence of oxygen. Inside digesters, waste matter degrades and releases bio-gas, rich in methane, a secret energy produced by our waste! Following recuperation, the bio-gas can be eliminated by incineration in a flare-stack or made use of for energy, thanks in particular to cogeneration. The simultaneous production of electricity and heat can be used in industry to heat buildings for example, or even as a fuel.