III
Next-Generation Technologies and Feedstocks
Several presenters described the efforts of federal agencies and the private sector to develop next-generation bioenergy technologies and prospects for transitioning from a biofuel industry dominated by corn-based ethanol to one based on a more diverse set of feedstocks. One of the largest of these programs is the U.S. Department of Energy’s (DOE’s) Biomass Program.1 This program is currently focused on deploying cellulosic technologies—building pilot commercial-scale biorefineries, often partnering with industry. The program also conducts basic technology development research focused both on cellulosic ethanol as well as on other advanced fuels, such as green diesel and green gasoline, which can be substituted for petroleum-based fuels.
Annual DOE funding for these activities has averaged about $100 million. The 2009 stimulus funding increased the level of funding dramatically—by an additional $800 million. The additional funds are being used for demonstration and pilot-scale refineries, as well as supplementing previously funded commercial-scale biorefinery projects. DOE also funds analytical work in the areas of lifecycle analysis of water, greenhouse gas emissions, and land-use changes.
DOE currently funds three Bioenergy Centers, one which includes a focus on sustainability, the Great Lakes Bioenergy Research Center (GLBRC) in Madison, Wisconsin. The GLBRC sustainability program is designed to improve carbon balances across the entire biofuel life cycle and to seek ways to enhance ecosystem services in biofuel landscapes. Other GLBRC activities seek to improve plant biomass, biomass processing, and cellulosic conversion technologies.
Many private companies, such as British Petroleum (BP), are also conduct-
ing research on next-generation biofuels. In addition to supporting the Energy Biosciences Institute in Berkeley, California, BP has formed partnerships with DuPont and Verenium.
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The DuPont program is focused on developing efficient ways to produce biobutanol, a fuel with a lower emissions profile and higher energy density than corn-based ethanol. A pilot plant is under construction in the United Kingdom, and a second plant is expected to be built in the United States in the 2012-2013 timeframe.
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BP is also partnering with Verenium, a startup company developing cellulosic conversion technologies. It is planning to build the first cellulosic commercial-scale biofuel production plant in Florida next year with full production predicted to begin by 2012. The plant will use a biochemical pathway that BP expects to be more competitive in the long run because costs are not as dependent on scale as are plants using thermal chemical or biochemical processes.
During the workshop, a representative from a venture capital firm talked about research being done by ZeaChem, which bypasses more traditional thermochemical and biochemical processes. The new process can be used to produce both biofuels and industrial chemicals using cellulosic feedstocks.
Another presenter described efforts to develop other biomass-derived fuels—hydrocarbon biofuels. He explained that hydrocarbon biofuels have the same energy content as petroleum, and thus do not create a mileage penalty. He added that these fuels can use the existing infrastructure facilities developed for gasoline—transport pipelines, fuel pumps, and storage facilities eliminating the need to duplicate infrastructure.
Several presentations discussed potential future feedstocks. For example, the U.S. Forest Service and the Oak Ridge National Laboratory are currently updating bioenergy feedstock estimates in the 2005 billion-ton study.2 The initial study suggested that about 400 million tons could be provided from wood sources— logging residue, forest thinnings, mill residue, and urban wood wastes. Short-rotation woody crops were counted as an agricultural source. These estimates are now being revised to indicate the economic feasibility and sustainability of woody biomass feedstocks at a county level. Unlike other potential cellulosic feedstocks, woody biomass already represents a large share of total U.S. renewable energy supplies, and can be used for liquid fuels as well as to produce electricity and heat. With more than half the states in the nation now having renewable portfolio
2 |
Perlack, Robert D., Lynn L. Wright, and Anthony F. Turhollow. 2005. Biomass as a Feedback for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply. A report prepared for the United States Department of Energy and the United States Department of Agriculture. Oak Ridge, TN: Oak Ridge National Laboratory. Available at www.ornl.gov/~webworks/cppr/y2001/rpt/123021.pdf. |
standards, demand for woody biomass to produce electricity is likely to grow, competing with its use as a liquid transportation fuel feedstock.
Several federal agencies and land grant universities are collaborating in a regional biomass feedstock partnership to conduct field trials of potential feedstocks and to assess the impacts of these crops on soil carbon, hydrology, and water quality, as well as direct greenhouse gas emissions. An important aspect of the research is exploring how energy crops can best be integrated with current cropping systems. USDA is supporting research to assess how crop residues, such as corn stover, can be used as cellulosic feedstocks and harvested in ways that maintain soil organic carbon and protect croplands from erosion. USDA is also conducting research to develop varieties of perennial grasses and management practices that promote greater biomass feedstock yields.
One important issue that arose in numerous discussions was the need to understand the impacts of changes in land use. Many participants expressed concern about potential negative impacts associated with the expansion of biofuel production on marginal lands and the withdrawal of land from the Conservation Reserve Program (CRP). Growing economic pressures are likely to lead to the expansion of feedstock production on these lands without an adequate understanding of the value of the ecosystem services provided by these lands and the potential impacts if these services are lost. However, some research is now underway to assess the likely impacts of changes in land use associated with the expansion of energy crops and the potential effects on watershed scale hydrological flows, changes in soil nutrients, biodiversity, and pest suppression. (Appendix F).
A member of a National Academies committee assessing the status of various technologies for the production of alternative liquid transportation fuels discussed the major conclusions of a recent report.3 The study found that biomass (from plants and wastes) could be cost-competitive with petroleum over the next 10-25 years, leading to lower greenhouse gas emissions and reduced dependence on imported petroleum. The report estimates that approximately 500 million tons of biomass feedstocks could reasonably be produced annually and converted to fuels without major environmental impacts or impacts on food availability (Table 1). Different cellulosic feedstocks with woody biomass are expected to have the lowest costs, followed by straw and high-yield grasses. The report suggests that 0.5 million barrels/day of gasoline equivalent can be produced by 2020 and 1.7 million barrels/day by 2035.
Reaching these levels by 2020 will require increased funding for large demonstration facilities and adoption of low-carbon fuel standards; a carbon price, or explicit carbon-reduction targets; and accelerated federal investments in these
3 |
America’s Energy Future Panel on Alternative Liquid Transportation Fuels, National Academy of Sciences, National Academy of Engineering, and National Research Council. 2009. Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts. Washington, DC: National Academies Press. Available at http://www.nap.edu/catalog.php?record_id=12620. |
TABLE 1 Estimated Cellulosic Feedstock Production for Biofuels
Feedstock Type |
Millions of Dry Tons |
|
Current |
2020 |
|
Corn stover |
76 |
112 |
Wheat and grass straw |
15 |
18 |
Hay |
15 |
18 |
Dedicated fuel crops |
104 |
164 |
Woody residuesa |
110 |
124 |
Animal manure |
6 |
12 |
Municipal solid waste |
90 |
100 |
Total |
416 |
548 |
aWoody residues currently used for electricity generation are not included in this estimate. Source: NRC America’s Energy Futures Report: “Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts,” Workshop Presentation by John Miranowski, June 23, 2009. |
new technologies. Many participants noted that to ensure the sustainability of these new fuels, economic incentives will also need to be provided to farmers and developers to use a systems approach—addressing soil, water, and air quality; carbon sequestration; wildlife habitat; and rural development. As it is expected to take at least until 2030 to attain large-scale cellulosic fuel production, most participants agreed that meeting this goal will require the building of tens to hundreds of conversion plants, as well as associated transport and distribution infrastructure facilities.