Biomass energy is produced from non-fossilized materials derived from plants. Wood and wood waste are the largest sources of biomass energy followed by energy from municipal solid waste (MSW) and alcohol fuels. In 2004, biomass accounted for 47% of renewable energy consumption, with about 50% of this used for heating, 40% for electrical power production, and the rest as transportation fuel.
Wood – Wood biomass includes wood chips from forestry operations, residues from lumber, pulp/paper, and furniture mills, and fuel wood for space heating. The largest single source of wood energy is “black liquor,” a residue of pulp, paper, and paperboard production. It supplies over 50% of these industries’ energy requirements. Lumber mills and furniture manufacturers use chips, sawdust and bark for nearly 60% of their energy requirements. A small but growing amount of wood is co-fired with coal in utility power plants. Cordwood, wood chips, and pellets made from sawdust are used for space and water heating in buildings, including in over two million households as primary or supplemental heating fuels.
Municipal Solid Waste and Biogas – Waste-to-energy facilities burned 29 million tons of MSW in 2004 to produce heat and electricity. There are also about 380 landfills that recover methane, which forms as waste decomposes in low-oxygen (anaerobic) conditions. The methane is burned to produce electricity and heat. Methane is also produced in anaerobic “digesters” for heat and electricity generation at municipal sewage treatment facilities, concentrated livestock operations, and dairy farms.
Biofuels – Biofuels include alcohol fuels, such as ethanol, and “biodiesel,” a fuel made from grain oils and animal fats. Most biofuel used in the United States is fuel ethanol produced from corn. Nearly all fuel ethanol is consumed as a gasoline oxygenate in oxygenated or reformulated gasoline or as a gasoline enhancer in fuels such as “gasohol” (also known as E-10, a 10% ethanol- 90% gasoline fuel). In 2004, total consumption of fuel ethanol was about 3.5 billion gallons, the equivalent of about 2.3 billion gallons of gasoline on an energy content basis, or the amount of gasoline consumed in 4.3 million passenger cars. Biodiesel use is small but its use in diesel engines and for heating is increasing.
Source: Energy Information Administration