Introduction to Biomass
"Woodchips, Stalks, and Switchgrass" - Cellulosic Biomass Resources Cellulosic feedstocks such as switchgrass, first came to the attention of many in America when President Bush spoke in his January 31, 2006, State of the Union address of producing biofuels by 2012 using "woodchips, stalks and switchgrass" as the source of cellulosic biomass for producing ethanol. The President also put forward the advanced energy initiative which supported a 22% increase in clean-energy research and set a goal of replacing 75% of the oil imports from the Middle East by 2025. The 2007 State of the Union address re-enforced the concept of using cellulosic biomass for producing ethanol. The president ramped up the goals for alternative fuel use by proposing that the U.S. reduce gasoline consumption by 20% in ten years. The legislation that was passed in 2007 to support the President’s goals, the Energy Independence and Security Act (EISA) of 2007 (H.R. 6), established Renewable Fuel Standards that will require, by 2022, very large supplies of cellulosic biomass in addition to the grains and oils already being used. The potential exists in the U.S. for large supplies since cellulosic biomass can include everything from primary biomass sources of energy crops and forest thinnings or residuals harvested or collected directly from the land, to secondary biomass sources such as sawmill residuals, to tertiary biomass 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 potential future availability of agricultural and forestry biomass in the U.S. was reported in 2005 in a joint DOE and USDA document entitled “Biomass as Feedstock For a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply” ; Perlack et al. (2005). The report indicates a technical availability of about 200 million dry tons from the agriculture sector with yields, collection technology and crop management approaches in place in 2001. However scenarios of possible future changes in crop yield, crop management and harvest technology, and in use of perennial energy crops (such as switchgrass) suggests that about 400 to nearly 1 billion dry tons could be technically derived from the agricultural sector later this century. Details on individual crops are provided in the Feedstocks Section of the Biomass Energy Data Book. 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. The major crops (especially corn) are the primary source of lignocellulosic biomass from the agricultural sector. Changes in the way that land is managed will be necessary for increasing biomass resource availability in the U.S. An update of the biomass supply assessment is currently underway including consideration of economic constraints. The current summary tables will be replaced with updated information when they become available. One of the larger unexploited sources of cellulosic biomass is wood that needs to be removed from forests to reduce the risk of forest fires. Well over 8 billion dry tons of biomass has been identified by the U.S. Forest Service as needing fuel treatment removal (Perlack et al., 2005). The amount of this biomass potentially available for bioenergy uses is estimated to be about 60 million dry tons annually. This estimate takes into consideration factors affecting forest access, residue recovery and the desirability of using some of the recoverable biomass for conventional wood products. The fraction that could be available annually for bioenergy and bioproducts is less than 1% of the total size of the fuel treatment biomass resource. The other large underutilized sources of woodchips are logging residues and urban wood residues. In the case of forest biomass, the relatively high costs of removal, handling, and transportation have not, in the past, compared favorably to their relatively low value as bioenergy resources. Factors affecting the rate at which this source of material will become available for bioenergy includes public opinion toward this type of removal, as well as delivered costs and the extent to which technology is developed for utilizing small diameter wood for products other than bioenergy. The compost market already competes for urban wood resources. A factor that could greatly affect the amount of wood used for bioenergy, especially of forest fuel treatment removals, is that the definition of “renewable biomass” in EISA 2007 does not include thinnings and residues from federal forests, and some woody feedstocks from private forests except where that biomass is “obtained from the immediate vicinity of buildings, and other areas regularly occupied by people, or of public infrastructure, at risk from wildfire.” While the legislation does not prohibit the use of forest thinnings and fuel reduction treatments from federal forests for bioenergy or bioproducts, it does exclude them from qualifying as feedstocks suitable for meeting the Renewable Fuel Standard targets in EISA 2007. Bills were introduced in both the Senate (S. 2558) and House (H.R. 5236) in an attempt to revise the definitions to include sustainably collected fuel reduction treatments from federal forestlands. Those bills have been referred to committees. The Biomass
Research and Development Technical Advisory Committee has provided
numerous
recommendations to DOE, USDA and other
Federal Agencies on the research and development needed to
ensure that
a broad portfolio of diverse domestic feedstocks is available
for our nation's energy and chemical supplies. The Executive
Summary
of the Roadmap for Bioenergy and Biobased Products in the
U.S. states
that significant research breakthroughs are needed in a number
of
key area including
advances
in plant science to improve the cost effectiveness of converting
biomass to fuel, power, and products. Additionally, it recommends
that R&D in geographical information systems will help the
U.S. more accurately identify biomass availability. Finally,
it recommends a focus on advancements in harvesting methods for
both
agricultural and forest resources. Additionally,
the report Increasing Feedstock Production for Biofuels:
Economic Drivers, Environmental Implications, and the Role of
Research was released in 2008. The White House. 2007 and 2008 State of the Union addresses. http://www.whitehouse.gov/news The Energy Independence and Security Act of 2007 (H.R.6); final version: http://thomas.loc.gov/cgi-bin/query/z?c110:H.R.6 Perlack, R.D., Wright L.L., Turhollow, A.F., Graham, R.L., Stokes, B.H., and Erbach, D.C., 2005. Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply. DOE/GO-102005-2135 also ORNL/TM-2005/66. A joint U.S. Department of Energy and U.S. Department of Agriculture report available online at: http://www1.eere.energy.gov/biomass/publications.html Biomass Research and Development Technical Advisory Committee. Roadmap for Bioenergy and Biobased Products in the United States, October 2007. At: http://www1.eere.energy.gov/biomass/pdfs/obp_roadmapv2_web.pdf Biomass Research and Development Technical Advisory Committee. Increasing Feedstock Production for Biofuels: Economic Drivers, Environmental Implications, and the Role of Research, 2008. Available at: http://www.brdisolutions.com |
