Biomass Overview

Biomass is material that comes from plants. Plants use the light energy from the sun to convert water and carbon dioxide to sugars that can be stored, through a process called photosynthesis. Some plants, like sugar cane and sugar beets, store the energy as simple sugars. These are mostly used for food. Other plants store the energy as more complex sugars, called starches. These plants include grains like corn and are also used for food.

Another type of plant matter, called cellulosic biomass, is made up of very complex sugar polymers (complex polysaccharides), and is not generally used as a food source. This type of biomass will be the future feedstock for bioethanol production. Specific feedstocks being tested include agricultural and forestry residues, organic urban wastes, food processing and other industrial wastes, and energy crops. For more detailed information on current and future biomass resources in the United States see the feedstock section.

In 2005, biomass production contributed 2.7 quadrillion Btu of energy to the 69.1 quadrillion Btu of energy produced in the United States or about 4% of total energy production. Since a substantial portion of U.S. energy is imported, the more commonly quoted figure is that biomass contributed 2.7 quadrillion Btu of energy to the 99.8 quadrillion Btu of energy consumed in the United States or about 3%. At present, wood resources contribute most to the biomass resources consumed in the United States and most of that is used in the generation of electricity and industrial process heat and steam. The industrial sector (primarily the wood products industry) used about 1.4 quadrillion Btu in 2005. The residential and commercial sectors consume .04 quadrillion Btu of biomass; however, this figure may understate consumption in these sectors due to unreported consumption, such as home heating by wood collected on private property. The use of biomass fuels such as ethanol and biodiesel by the transportation sector is small but rising rapidly.

There are many types of biomass resources currently used and potentially available. This includes everything from primary sources of crops and residues harvested/collected directly from the land, to secondary sources such as sawmill residuals, to tertiary sources of post-consumer residuals that often end up in landfills. Biomass resources also include the gases that result from anaerobic digestion of animal manures or organic materials in landfills. The estimated availability of agricultural and forestry biomass in 2001 was recently reported in a document entitled “Biomass as Feedstock For a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply;” prepared by Oak Ridge National Laboratory staff (for the Department of Energy) together with scientists from the U.S. Department of Agriculture (USDA), Agricultural Research Service and USDA Forest Service. The ultimate limit for the amount of biomass that can be sustainably produced on agricultural land in the United States depends on land availability. The areas of the country with adequate rainfall and soil quality for production and harvest of energy crops are roughly the same areas where major crops are currently produced in the United States. Changes in the way that land is managed will be necessary for increasing biomass resource availability in the U.S.

For additional overview information, visit the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy's Biomass Program at: http://www1.eere.energy.gov/biomass/index.html