Renewable Gas Guarantees of Origin are issued for those gases that are environmentally friendly and CO2 free. Most popular renewable gas in the EU is biomethane. By the process of anaerobic digestion, organic waste produces biogas. The CO2 component gets removed from this biogas, which makes it CO2 free, environmentally friendly, and ready to be injected into the gas grid. For each MWh injected into the grid, the biomethane producer gets 1 RGGO, which can be sold together or separately with the gas. Slightly less popular renewable gases that are also in the RGGO system are bio-SNG (synthetic natural gas) and green hydrogen.