Biomass Energy Overview
In 2010, biomass energy production contributed 4.3 quadrillion Btu (British thermal units) of energy to the 75 quadrillion Btu of energy produced in the United States or about 5.7% of total energy production. Since a substantial portion of U.S. energy is imported, the more commonly quoted figure is that biomass consumption amounted to 4.3 quadrillion Btu of energy of the 98 quadrillion Btu of energy consumed in the United States in 2010 or about 4.4%. 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. However, the contribution of biofuels has nearly tripled since 2005 and now accounts for about 43% of all biomass consumed. While most biofuels feedstocks are currently starches, oils and fats derived from the agricultural sector, whole plants and plant residues will soon be an important feedstock for cellulosic biofuels. Algae are being developed as a source of both oil and cellulosic feedstocks. The industrial sector (primarily the wood products industry) used about 2.2 quadrillion Btu in 2010. The residential and commercial sectors consume 0.05 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 now at about 1 quadrillion Btu. This is less than the total amount of biofuels produced because some liquid biofuels are used by other sources.
The tables in the introduction showing the accounting of energy production and consumption are all derived from Energy Information Administration (EIA) reports. Information on assumed Btu content of most fuels and the assumptions used in estimating the total Btus consumed in the US can be found in the EIA Monthly Energy Review at: http://www.eia.gov/totalenergy/data/monthly/pdf/sec13.pdf. A key point is that gross heat contents (higher heating values) of fuels and biomass feedstocks are used rather than the net heat contents (lower heating values) commonly used in Europe. Differences may range from 2 to 10%. The assumptions for the gross heat content of wood and consumption estimation were found under a discussion of “wood conversion to Btu” in the EIA glossary that can be accessed at http://www.eia.gov/tools/glossary/. The EIA glossary explains that many factors can affect wood heat content but EIA calculations always assume 20 million Btu per cord of wood. This is actually slightly higher than the heat content values for wood found from multiple other sources. A table, showing both higher and lower heating values for many biomass fuels, is included in appendix A of the Biomass Energy Data Book. Factors for translating cords to other units of wood are also found in the appendix A. The EIA glossary also notes that EIA biomass waste data includes energy crops grown specifically for energy production. This is likely due to the fact that insufficient amounts of dedicated energy crops are currently being used to warrant separate tracking.
The Renewable Fuels Association characterized 2007 as a year that ushered in a new energy era for America. The enactment of the Energy Independence and Security Act of 2007 (H.R. 6) coupled increased vehicle efficiency with greater renewable fuel use. The law increased the Renewable Fuel Standard (RFS) to 36 billion gallons of annual renewable fuel use by 2022 and required that 60 percent of the new RFS be met by advanced biofuels, including cellulosic ethanol. The recent increase in the percentage of biomass consumed in the U.S. is largely due to the increased production and consumption of biofuels.
Biomass energy production involves the use of a wide range of technologies to produce heat, steam, electricity and transportation fuels from renewable biomass feedstocks. Descriptions of many of the biomass technologies currently in commercial use or being tested are included in the Biomass Energy Data Book. Information on the characteristics and availability of utilized or potential biomass feedstocks as well as information on relevant policies are also included. Information on economics and sustainability is included to a limited extent since the limited information publically available is generally based on estimates rather than factual data.
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