Which material is the main combustible component of biogas?

Methane is the main combustible component of biogas.

Biogas forms when microorganisms break down organic material without oxygen in a process called anaerobic digestion. The gas mixture typically contains methane and carbon dioxide, along with small amounts of water vapor, hydrogen sulfide, and other gases. Methane provides most of its usable energy because it burns readily.

Feedstocks include manure, sewage sludge, food waste, and crop residues. In a digester, microbes convert complex organic matter through several biological stages. The remaining material, called digestate, can sometimes be used as a soil amendment after appropriate treatment.

Raw biogas is not the same as biomethane. Biogas contains substantial carbon dioxide and impurities, while biomethane is upgraded to a higher methane concentration for pipeline injection or vehicle fuel. Methane is also a powerful greenhouse gas if it escapes untreated.