There have been three generations of biomethane to date. These three generations involve different production techniques and biomass resources. The three generations are additional, and can be fed in to existing gas networks.
• biomethane from wet biomass-to-gas is produced using the methanization technique.It comes from the biodegradation of organic matter such as organic, household, and agricultural waste, or from wastewater plants.It is now available on an industrial scale.
• biomethane from dry biomass-to-gas is produced via the methanation technique.It comes from lignocellulose materials like wood or straw, as well as from paper industry by-products.
• biomethane from micro-algae is produced via a direct transformation process.It comes from micro-algae (and not from primary resources) grown in very high-yielding photosynthetic reactors using natural light, water and minerals, while recycling CO2. The technologies involved are still at an experimental scale.