Introduction to biogas and biomethane
Biogas is produced by the anaerobic digestion (without oxygen) of organic matter from agricultural, livestock and forestry residues, municipal solid waste and wastewater. It comes from renewable sources, unlike fossil natural gas, but has a similar composition with a high methane content. Biomethane is biogas that has undergone an “upgrading” process, which removes impurities and CO₂ to reach roughly 95% methane; it can be injected into the gas grid mixed with natural gas and used for electricity, heat and vehicles.
Uses and applications of biomethane
Biomethane is a direct substitute for natural gas and can be injected into the existing grid without additional infrastructure investment. It can decarbonise homes and industry, power vehicles as bio-CNG (compressed) or bio-LNG (liquefied), decarbonise industrial processes that cannot be electrified, serve as a feedstock for renewable hydrogen and support the circular economy by managing organic waste.
The situation of biogas and biomethane in Spain and Europe
Spain has high potential thanks to its agricultural, livestock and urban waste, but development has lagged other European countries because of regulatory and administrative barriers, complex environmental permitting and social-acceptance issues. CNMC Circular 2/2025 (BOE-A-2025-7661), which regulates access to and injection of renewable gases into the gas system, is a decisive advance, and the Guarantees of Origin system for renewable gases should, together with a clearer regulatory framework, boost project development. The International Energy Agency estimates biomethane could cover up to 10% of global gas demand by 2050, and the REPowerEU package gives it a priority role, with a target of 35 bcm of annual production by 2030. Biomethane still costs more than fossil natural gas.
Conclusions: challenges and opportunities
Social acceptance is the main obstacle, often due to limited public knowledge of how biomethane is produced and of its benefits. Biomethane recovers organic matter that would otherwise go to landfill, reducing waste and supporting the circular economy; it creates jobs, boosts rural development, strengthens energy security and reduces dependence on fossil gas. Its consolidation depends on social acceptance and on a regulatory environment that provides legal certainty and recognises its environmental value.
