biogas

n. fuel that is derived from organic material (also biogas)

Biogas typically refers to a (biofuel) gas produced by the anaerobic digestion or fermentation of organic matter including manure, sewage sludge, municipal solid waste, biodegradable waste or any other biodegradable feedstock, under anaerobic conditions. Biogas is comprised primarily of methane and carbon dioxide.
See more at Wikipedia.org...

n. biogas

n. biofuel, fuel that is derived from organic material

n. biogas, gas made up of methane and carbon dioxide that is the result of organic decomposition