Biogas is a mixture of various types of gases, largely methane and carbon dioxide. Biogas is produced by a process called “anaerobic digestion”, which is the bacterial fermentation - without oxygen - of biomass that can include: agro-industrial waste, solid and liquid waste from livestock farms, sewage sludge, by-products from agriculture, the organic fraction of solid urban waste (OFMSW) and specifically-grown crops. Biogas enables the economical, sustainable and programmable production of energy, feeding it into a cogeneration plant that in turn generates totally renewable electrical and thermal energy.