What Is Biomass?

• Many sources contribute renewable biomass
  
  Biomass energy, at the level of consumption, is virtually indistinguishable from other energy. The main difference is its source. Biomass refers to relatively recently living organic material such as wood, leaves, paper, food waste manure and other items usually considered garbage. Biomass fuel sources burn cleaner than fossil fuels; that is, they emit less carbon dioxide and other greenhouse gases and do not pose the environmental risk of nuclear energy. Unlike fossil fuels, the carbon emitted from the production of biomass energy does not significantly upset the atmospheric balance because it has not left the carbon cycle, a process which takes carbon dioxide from the air during photosynthesis and stores it in the living tissue of plant cells. In 2008, biomass produced about 0.5 percent of total U.S. energy consumption.
  
  

How is Biomass Used?

• Compost is a low-tech form of biomass energy
  
  The most simple use of biomass to produce energy is burning. The energy can be used directly as light and heat or can be transformed to produce electricity by boiling water, which produces steam and spins a turbine. Another low-tech uses of biomass energy is mulching, which uses the organic content of biomass to fertilize soil and feed plants. The more high-tech methods of extracting energy from biomass also involve transforming the physical organic matter itself into a more combustible material. Hydrogasification adds hydrogen gas to carbon in biomass to produce highly flammable methane. Hydrogenation actually converts biomass into oil by combining it with carbon monoxide. Other methods convert biomass into fuels that can be used everyday in trucks and cars.
  
  

Biofuel

• Biodiesel is the world's cleanest burning automobile fuel
  
  Because of auto emissions' high contribution to air pollution, relatively clean-burning bio ethanol and biodiesel are probably the most significant energy contributions of biomass. A variety of distillation and fermentation processes produce ethyl alcohol from biomass, which is then convertible into the biofuel ethanol. The most common sources of biofuel ethanol are sugar cane, beets, corn and molasses, though virtually any sugar or starch that can produce alcohol can produce bio ethanol. Alcohol-based fuels, however, are only about one third as efficient as gasoline and are highly corrosive to engines. Safer watered-down versions of ethanol lead to reduced efficiency and intermittent engine operation. On the other hand, pure biodiesel is the lowest emission biomass energy fuel source and is ideal for transportation. It begins as vegetable oil or animal fat which, when heated to lower its viscosity and combined with ethanol or methanol, produces an extremely efficient fuel that contains more hydrogen and oxygen and less carbon than fossil fuel diesel. Though it actually cleans engines as it is burned, automobiles manufactured for conventional diesel shouldn't use more than a 15 percent biodiesel mixture.
  
  

Anaerobic Digestion

• Digesters break down sewage into usable material
  
  A final use of biomass to produce energy is anaerobic digestion. This high-tech and expensive process harnesses microorganisms to break down liquid biodegradable wastes such as sewage in highly sensitive digesting tanks. This reduces the amount of gas escaping into the atmosphere and captures it for potential use as fuel. Despite the difficulties associated with anaerobic digestion, it has been cited by the United Nations as one of the most promising applications of biomass energy technology.