Biogas is the product of anaerobic digestion (decomposition without oxygen) of organic matter. It is mostly made up of methane and carbon dioxide, as opposed to natural gas, which is composed of nearly all methane and other hydrocarbons. Biogas is sometimes called swamp gas, landfill gas, or digester gas, all due to the way it is formed. When its composition is upgraded to a higher standard of purity, it can be called renewable natural gas and used as an alternative fuel in the same forms as conventionally derived natural gas: compressed natural gas (CNG) and liquefied natural gas (LNG).
Biogas comes from a variety of sources, including but not limited to sewage sludge, agricultural wastes, industrial wastes, animal by-products, and municipal solid wastes. The benefits of using biogas are many, and they are similar to the benefits of using natural gas. It is a domestic and renewable resource and directly eliminates greenhouse gas emissions by preventing methane release into the atmosphere (methane is 21-times stronger as a greenhouse gas than carbon dioxide). Its production positively affects local economies by providing jobs. Furthermore, the anaerobic digestion required to produce biogas treats waste naturally, requires less land area than aerobic composting, reduces the amount of waste material, reduce waste odors, and produce sanitized compost and nutrient-rich liquid fertilizer.
Biogas is growing as an alternative fuel. A 2007 report estimated that 12,000 vehicles are being fueled with upgraded biogas worldwide, with 70,000 biogas-fueled vehicles predicted by 2010. A majority of these vehicles are in Europe. However, Gober (or Gobar) gas, a biogas created from cow dung, is also growing as a fuel in India and Pakistan.
Links
- To learn more about biogas, please visit the Department of Energy's Alternative Fuels Data Center.
- For more information on anaerobic digestion and biogas safety, please visit Penn State University's biogas homepage.
- To get in contact with biogas consultants, equipment dealers, and funders, visit Penn State University.
