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Biomass includes all plant and plant-derived material — essentially all energy originally captured by photosynthesis. This means that biomass is a fully renewable resource and that its use for biomass-derived fuels, power, chemicals, materials, or other products essentially generates no net greenhouse gas. (You must consider any fossil-fuel use to grow, collect, and convert the biomass in a full life-cycle analysis, but the carbon dioxide released when biomass is burned is balanced by the carbon dioxide captured when the biomass is grown.) Its production and use will also generally be domestic, so it has substantial environmental, economic, and security benefits.
Biomass is already making key contributions today. It has surpassed hydro-electric power as the largest domestic source of renewable energy. Biomass currently supplies over 3% of the U.S. total energy consumption — mostly through industrial heat and steam production by the pulp and paper industry and electrical generation with forest industry residues and municipal solid waste (MSW). Of growing importance are biomass-derived ethanol and biodiesel which provide the only renewable alternative liquid fuel for transportation, a sector that strongly relies on imported oil.
In addition to today's uses of biomass, and historic ones for food, shelter, and clothing, there is significant potential for new biomass feedstocks to dramatically expand the use of biomass in order to continue to reduce our reliance on fossil fuels. The first feedstocks for this "new" biomass might come from opportunities with particular industrial residues, but beyond that, large-scale expansion of biomass is expected to come from forestry and agricultural residues. The latter includes cellulosic stalks, leaves, husks, and straw in addition to the starchy grains and oily seeds currently used. In the longer term, the biomass industry could support dedicated energy crops specifically grown for energy use.
Of the many possible conversion technologies for expanded biomass use, two of the most promising are the sugar platform and the thermochemical platform. These are referred to as "platforms" because the basic technology would generate base or platform chemicals from which industry could make a wide range of fuels, chemicals, materials, and power. These platform chemicals and wide range of products are analogous to the current petrochemicals industry. The promotion of "biorefineries" as a major new domestic biomass industry is, along with reducing dependence on imported oil, the major objective of the Biomass Program.
The Biomass Program process design for sugar platform technology uses thermochemical hydrolysis pretreatment of hemicellulose and enzymatic hydrolysis of cellulose to break those two polymeric carbohydrates down to their component sugars for subsequent fermentation or other processing to valuable fuels, chemicals, and materials. Separated lignin — the third component comprising the bulk of biomass material — can also be processed into valuable products or can be burned to provide heat, steam, and electricity for the process operation.
Thermochemical platform technology heats biomass with limited oxygen to gasify it to synthesis gas (a mixture of carbon monoxide and hydrogen) or liquefy it to pyrolysis oil. Because combustion and catalytic conversion processes are a function of the interaction of the individual molecules of feedstock material with oxygen or a catalyst, respectively, work better with liquids and gases than with solids. Therefore, biomass converted to synthesis gas, pyrolysis oil, or hydrothermal liquid (from another thermochemical platform process) burns more efficiently than if it were in its original solid state. Or, instead of burning them, these biomass-derived gases or liquids can be catalytically converted to other valuable fuels, chemicals, or materials.
For Further Reading
Some of the following documents are available as Adobe Acrobat PDFs. Download Acrobat Reader.
- Biofuels for Your State: Helping the Economy and the Environment (PDF 322 KB)
- Biopower Program, Activities Overview (PDF 389 KB)
- The Biomass Economy, Excerpt from National Renewable Energy Laboratory 2002 Research Review, 1st Edition (PDF 664 KB)
- The National Bioenergy Center: Laying the Foundation for Biorefineries (PDF 544 KB)
- Browse biomass topics in the EERE Energy Information Portal
- Search the Biomass Document Database
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