BIOMASS

Biomass comes directly or indirectly from recent photosynthesis, i.e., biomass is an indirect form of solar energy. Most biomass energy is utilized via direct combustion, although some is indirectly used via the production of fuel gases and liquids. Possible options for fuel production from biomass include methanol from woody biomass, and ethanol from fermentation of biomass-derived sugars (e.g., large-scale sugarcane use in Brazil, and some made from corn in the U.S.). Sewage gas (almost pure methane) is produced in the decay process of some biomass.

The heating value of biomass materials is lower than that of fossil fuels, and thus, biomass is uneconomical to transport over long distances. Biomass materials include wood, plants, and solid wastes (municipal and agricultural). The municipal wastes include plastics, paper, cardboard, and yard cuttings; the agricultural wastes include nut hulls, rice hulls, corn cobs, coffee grounds, and bagasse. In Hawaii, sugar cane refuse (bagasse) is used to generate electricity. In 1992, biomass was used to generate 7,300 MW of electricity.

methane_gas

Methane gas extraction from landfill [Source: Tennessee Valley Authority (TVA)].


Last updated: December 12, 2005

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