Biogas

Biogas refers to gas used in energy production produced from biological processes rather than chemical processes. Biogas is generated from anaerobic digestion (the breakdown of organic matter by bacteria without oxygen), resulting primarily in methane gas, carbon dioxide (CO2), and trace amounts of nitrogen, hydrogen, and carbon monoxide. It differs from natural [Page 66]gas—commonly used as a fuel source—in that it has not had all other gases (aside from methane) removed through chemical processing. Biogas occurs naturally in compost heaps, as swamp gas, and as a result of enteric fermentation in cattle and other ruminants, which are the estimated source of 3 percent of greenhouse gas emissions related to global warming. The biogas produced from anaerobic digestion can be burned to produce heat, or used ...