Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 63
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts 2 Biomass Resources for Liquid Transportation Fuels America’s transportation systems will undergo major and multifaceted transformations as the nation addresses human-driven climate change, the availability and cost of liquid transportation fuels, and the need for energy security. Plant biomass has the potential to play an important role in America’s energy future. Plants convert solar energy to chemical energy naturally for their growth and development through the process of photosynthesis. Plant biomass can be produced sustainably and converted into liquid transportation fuels via biochemical conversion (Chapter 3) or thermochemical conversion (Chapter 4). Liquid transportation fuels derived from biomass feedstock are often referred to as biofuels. The amount of biomass that can be produced in an area depends on the local availability of sunlight, water, and other resources. In principle, biofuels are attractive alternatives to gasoline because they are made from renewable feedstocks and can decrease the net release of greenhouse gases by the transportation sector. Although those benefits are important, they must be viewed in the context of other societal needs that are also met by the nation’s land base, especially needs for food, feed, fiber, potable water, carbon storage in ecosystems, and preservation of native habitats and biodiversity. Responsible development of feedstocks for biofuels and expansion of biofuel use in the transportation sector would be economically, environmentally, and socially sustainable. This chapter addresses the questions raised in the statement of task regarding the following: The quantities of biomass that could potentially be produced and collected in a sustainable manner for use as feedstocks for liquid transportation fuels.
OCR for page 64
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts The input and costs involved in growing and harvesting the crops or in collecting the feedstock and delivering it to a biorefinery for production of liquid transportation fuels. The land-use, agricultural, price, greenhouse gas, and other environmental implications of biomass production for liquid fuels. Research and development (R&D) needed to advance production of biomass feedstock for transportation fuels. The chapter examines the quantities of different types of biomass that can be harvested or produced while minimizing competition between food and fuel and minimizing adverse environmental effects. It also assesses the total costs of various feedstocks that will be delivered to a processing plant for conversion to biofuel. The panel considered societal needs on the basis of recent analyses that have explored tradeoffs between using land for biofuel production and using it for food, feed, fiber, and other ecological services that land resources provide. CURRENT BIOMASS PRODUCTION FOR BIOFUELS Biofuel produced in the United States is overwhelmingly dominated by ethanol made from corn grain; biodiesel derived from soybean oil makes up most of the remainder. In the 2007 crop year (from September 2, 2007, to August 31, 2008), 3.0 billion bushels of corn, or 23 percent of the year’s harvest, was used to produce 8.2 billion gallons of ethanol (NCGA, 2008). Around 450 million gallons of biodiesel were also produced, about 90 percent of which was derived from the oil extracted from 275 million bushels of soybean, 17 percent of the year’s harvest (USDA-NASS, 2008a; NBB, 2008). On an energy-equivalent basis (in British thermal units), corn grain ethanol and soybean biodiesel together made up 2.1 percent of the liquid transportation fuel used in the United States in 2007 (EIA, 2008). The social, economic, and environmental effects of domestic biofuels have been mixed. Diverting corn, soybean oil, or other food crops to biofuel production could induce competition among food, feed, and fuel, but increases in crop price have helped to revive rural economies. From the perspective of farmers and small rural communities, development of ethanol plants has created greater local demand and higher prices for corn grain (and for soybean through parallel efforts associated with production of biodiesel). Local investment in and control of these plants have also provided well-paying employment opportunities
OCR for page 65
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts that reinvigorated many small midwestern communities, but some argue that the number of jobs added to the local economy is overestimated (Low and Isserman, 2009). For farmers, the increase in corn grain prices, which averaged $2.36 ± 0.40 per bushel of grain (25 kg) in 1973–2005 but $3.04 and $4.00 per bushel in 2006 and 2007 (USDA-NASS, 2008a), was of great importance. The increased prices were results of an increased global demand for corn as animal feed and for grain ethanol production. Higher commodity prices have also led to markedly higher values of fertile farmland, and have adversely affected low-income consumers in the United States and abroad and the drawing of land out of the U.S. Conservation Reserve Program (CRP). On a global scale, high commodity prices are expected to accelerate clearing of rain forest and savanna. There is growing concern about the use of grain for fuel instead of food. Other environmental concerns, especially the loss of nitrogen by leaching (Donner and Kucharik, 2008), have also been pointed out. Corn and soybean are renewable biofuel feedstocks, but large amounts of fertilizer and pesticide are often needed to grow them (Hill et al., 2006). The resulting greenhouse gas and other pollutant effects of those practices can be harmful to human health and the environment. Corn grain ethanol and soybean biodiesel are viewed by some as intermediate fuels in the transition from oil to advanced biofuels made from cellulosic biomass. As a biofuel feedstock, cellulosic biomass has numerous advantages over food and feed crops, including its availability from sources that do not compete with food and feed production. Biomass can be reclaimed from municipal solid-waste streams and from residual products of some forestry and farming operations. It can also be grown on idle or abandoned cropland, on which food or feed production is already minimal. Growing cellulosic biomass can require less fossil fuel, fertilizer, and pesticide inputs than growing corn and soybean (Tilman et al., 2006), especially if legumes (nitrogen-fixing plants) are included in the mix (NRC, 1989). In addition, cellulosic biomass can serve not only as a feedstock for biofuel production but also as a source of the heat and power required for biorefineries and thus displace fossil fuels and fossil-fuel-derived electric power (Morey et al., 2005). Therefore, this chapter focuses on the biomass resources available for cellulosic biofuel production. Sustainable Production of Biomass for Conversion to Biofuels Globally, about 12 billion acres of land are used for agriculture, about 4 billion of which are cultivated and the remainder used for grazing. Any substantial
OCR for page 66
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts expansion of agriculture to accommodate dedicated biofuel crops via the direct conversion of natural ecosystems—such as native rain forests, savannas, and grasslands—into cropland could threaten those ecosystems and reduce their biodiversity. Biofuels can also indirectly cause land to be cleared when fertile agricultural soils or food crops are used for biofuels. Such indirect land clearing provides land used to grow “replacement” food crops. Moreover, intact ecosystems are major storehouses of carbon: terrestrial vegetation stores as much carbon as the atmosphere does, and terrestrial soils store twice as much (Schlesinger, 1997). Dry biomass—whether wood of trees, hay, or corn stover—contains about 45 percent carbon. On combustion or decomposition, every ton of dry biomass contributes about 1.5 tons of carbon dioxide (CO2) to the atmosphere. In many cases, conversion of intact ecosystems to grain or fuel-crop production could incur losses of biomass and soil carbon to the atmosphere as CO2 that greatly exceeds the greenhouse gas savings associated with biofuel production on such lands for many years (Box 2.1) (Fargione et al., 2008; Searchinger et al., 2008). Biofuels offer opportunities for greenhouse gas reductions, but large amounts of cellulosic biomass will be needed. Sustainably produced biomass would be derived from various agricultural or forestry residues, from current waste streams, or from dedicated fuel crops grown on agricultural reserve land or on land so degraded that it is no longer cost-effective for commodity production (Tilman et al., 2006). The United Nations Environment Programme and other sources estimate that globally there are about 400–500 million hectares of such land (Campbell et al., 2008; Field et al., 2008). Collecting agricultural residues and producing biofuel crops both have environmental benefits and costs. Removing biomass and crop residues, such as corn stover, could increase soil erosion by wind and water and deplete soil carbon reserves, ultimately affecting water entry, retention, runoff, nutrient cycling, productivity, and other critical functions. Depending on the crop, soil type, and terrain, various amounts of biomass or crop residues need to be left on a field to mitigate soil erosion and sustain soil carbon and nitrogen (Wilhelm et al., 2007). The proportion of biomass that has to be left on the soil surface to prevent erosion is higher for annual crops than for perennial crops because of the tillage generally used to establish a new crop each year. Perennial crops, especially grasses, have dense long-lived root systems that can maintain soil resources. When ecosystems are cleared of perennial vegetation and converted to annual row crops, soil carbon stores tend to decline by 30–50 percent until a new equilibrium is reached (Davidson and Ackerman, 1993). Removal of plant residues, such
OCR for page 67
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts as corn stover or wheat or rice straw, without such offsetting practices as growing cover crops or decreasing tillage intensity, could reduce soil carbon to a lower equilibrium. A portion of the crop residue is needed for erosion and nutrient management and to sustain soil organic carbon, which is the carbon fraction associated with all types of organic matter, including plant and animal litter, microbial biomass, water-soluble organic compounds, and stabilized or recalcitrant organic matter (Stevenson, 1994; Johnson et al., 2006a). Removing plant residues for any purpose would decrease the annual carbon input, gradually diminish soil organic carbon (Figure 2.1), and threaten the soil’s production capacity (Johnson et al., 2006a). Therefore, a “systems” approach1 is required for sustainable biomass production to ensure that its production has a low impact on global food, feed, and fiber production and that addressing the biofuel problem does not aggravate other critical challenges, including soil, water, and air quality; carbon sequestration; greenhouse gas emissions; rural development; and wildlife habitat. A Landscape Vision of Feedstock Production The rapidly emerging technologies to develop and use lignocellulosic materials for production of bioenergy and bioproducts might offer an opportunity to reduce the environmental footprint of the transportation sector and improve the environmental sustainability of agriculture. For example, periodically mown perennial biomass crops could be used to reduce some of the agricultural production “externalities” if they are planted as buffer strips and in locations that would help to reduce soil erosion, improve water quality, sequester carbon, and provide wildlife habitat (Tilman et al., 2006; Doornbosch and Steenblik, 2007; Ernsting and Boswell, 2007; Fargione et al., 2008; Searchinger et al., 2008). Implementation of a landscape approach for producing biofuel feedstocks while addressing some of the externalities associated with agriculture could be made more feasible by precision agriculture (Giles and Slaughter, 1997; Tian et al., 1999; Ferguson et al., 2002; Khosla et al., 2002; Robert, 2002) and other changes (Zhang et al., 2002; Berry et al., 2003; Dinnes, 2004). Examples of how watershed-scale or landscape-scale management could potentially address those multiple 1 A “systems approach” to agriculture is a holistic or integrated framework that recognizes the connectivity of multiple processes that occur on the farm and in the ecosystem and that reach across spatial, temporal, and trophic dimensions and scales. The systems approach examines the connections and interactions between the different components that make up a system so that the relative effects of change on each component can be understood.
OCR for page 68
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts BOX 2.1 Effects of Land-Use Change on Greenhouse Gas Emissions Recent studies have focused on the life-cycle greenhouse gas emissions from different biofuels compared with gasoline or diesel. Despite some important disagreement, the prevailing view is that corn grain ethanol emitted less greenhouse gas than did gasoline, that biofuels from sugarcane provided an even greater benefit, and that cellulosic ethanol, once commercialized, would further increase the benefit (Farrell et al., 2006; Hill et al., 2006; Wang et al., 2007). Some earlier studies recognized that carbon sequestration achieved by changing practices to reduce carbon on a landscape could be offset by increased carbon releases on other landscapes, which would result in a smaller net decrease or even a net increase in total carbon emission (Murray et al., 2004; IPCC, 2006). However, emissions from change in land use were not explicitly included in the comparative analyses of different biofuels in the life-cycle assessment. If land is cleared and used to grow plants for biofuels, much of the carbon stored in the biomass and some of that in the soil is released as CO2. A more complete life-cycle analysis than the earlier biofuel analyses would deduct the carbon lost into the atmosphere from land-clearing and no longer being stored in an ecosystem. That approach is being implemented by the U.S. Environmental Protection Agency under the 2007 renewable fuels standard mandated in the Energy Independence and Security Act (EISA). Fargione et al. (2008) determined the greenhouse gas carbon released in converting forest or grassland to biofuel production, which they called the “carbon debt,” and the years of biofuel production required to “pay back” the debt. They argued that the carbon debt would arise from land where upland and lowland forest in Southeast Asia was converted to produce palm oil, where various forms of cerrado forest in Brazil were converted for production of biodiesel fuel, and where CRP grasslands were converted to corn for ethanol—scenarios with payback periods of 48 years (the CRP) to more than 400 years (lowland palm oil). If land converted to biofuel production had been sequestering carbon, as would occur with regrowing forests and conservation grasslands, it is also necessary to consider the greenhouse gas effects of forgoing the benefits that would have occurred on the same land if it had not been used for biofuel production. Similarly, in a global agricultural system, if land used for food production is converted to biofuel production, some portion of the decrease in food production will be replaced by cultivation elsewhere and to a substantial extent through the conversion of noncropland to cropland (Searchinger et al., 2008). This indirect cause of converting forest and grassland to cropland also creates a carbon debt that needs to be accounted for in order to evaluate effects on greenhouse gases fully. Searchinger et al. (2008) used the international model developed by the Center for Agricultural and Rural Development at Iowa State University and the Food and Agricultural Policy Research Institute at Iowa State University and the University of Missouri–Columbia to estimate emissions from such indirect land-use changes. They found that each acre of corn diverted to ethanol in the United States would result in roughly 0.8 acre of new cropland worldwide. They concluded that U.S. corn grain ethanol increased greenhouse gas emissions over 30 years by 93 percent relative to
OCR for page 69
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts gasoline and that it would take 167 years to pay back the carbon debt. Ethanol made from switchgrass grown on former corn land increased emissions over 30 years by 50 percent relative to gasoline. Estimating effects of land-use change on greenhouse gas emissions requires a worldwide agricultural land-use model, a basis of estimating which ecosystems will contribute to new cropland, and a basis of estimating carbon release per hectare. Each step contains uncertainties. The path through which land conversion takes place is complicated, requiring consideration of animal-feed by-products of biofuel production, crop-switching, reduction in food demand as a result of higher prices, likely regions of expansion, different yields in different countries, and alternative means of increasing production (for example, increased fertilizer use, drainage, or irrigation). All those factors interact and require at least a partial-equilibrium model for analysis. Because of the complexity, the exact magnitude of indirect carbon debt is difficult to determine with great certainty. Nevertheless, the analyses of Searchinger et al. (2008) show that conversion of fertile farmlands to biofuel production is likely to have caused substantial indirect greenhouse gas release via land conversion to pasture or row crops and that indirect effects cannot be ignored in determining the full life-cycle greenhouse gas effects of biofuels. The best way to minimize such indirect effects is to avoid using for biofuel production those fertile lands that are well suited for food and feed production. One way to deal with indirect land-use conversion, followed by the EISA, is to require calculation of indirect land-use change for each source or type of biofuel and to mandate only the biofuels that achieve specified reductions in greenhouse gas emissions relative to those from gasoline. The requirement has the obvious benefit of encouraging only biofuels that, on balance, reduce greenhouse gas emissions. One limitation of the approach is the failure to consider effects on food production and prices or other environmental effects of agricultural expansion, including loss of biodiversity and other ecosystem services. An alternative approach that takes into account both food and carbon limitations would mandate or provide incentives only for biofuels that present little risk of substantial emissions from land-use change. Such a policy would emphasize biofuel production from waste products or from feedstocks grown on marginal land (that is, areas that sequester little carbon or produce little food but can produce biomass for biofuels). Such a policy would be designed to avoid greenhouse gases, biofuel-food competition, and other potential environmental effects of agricultural expansion on water quality or quantity and biodiversity. It would also avoid the difficulty of estimating greenhouse gas emissions from indirect land-use conversions accurately. In summary, the greenhouse gas benefit of biofuels compared with petroleum-based fuels depends not only on direct greenhouse gas emissions from biofuels during their life cycle (that is, from the growth of biomass to the production and burning of the biofuels) but also on any indirect emissions that might be incurred by changes in land use. The appropriate quantification of indirect greenhouse gas emissions is being debated. Policies could play an important role in ensuring that the biofuels produced provide environmental benefits.
OCR for page 70
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts FIGURE 2.1 Conceptual diagram of how agriculture has affected soil organic matter and what may occur after various strategies for crop-residue removal. concerns while supplying the necessary volume of biofuel feedstocks are presented in Appendix E. BIOMASS RESOURCES The following is an assessment of biomass resources for liquid fuel production using technologies available and management practices known in 2008 and projected to be available in 2020. It is predicated on two fundamental principles: (1) that biomass production for liquid fuels should not compete for land on which an existing crop is produced for food, feed, or fiber or compete for pasture land that will be needed to feed a growing and increasingly affluent population, even with yield increases, and (2) that the environmental impact on land used for biomass production should be no worse than that of its previous use and provide greater benefits wherever possible (for example, reducing fuel loads in fire-prone areas, managing volumes of urban waste, and increasing soil carbon sequestration in restoration of native grassland ecosystems). Although many other possible visions of biomass availability that do not hold as closely to those two principles are possible, the panel chose to conduct its assessment with those two in mind.2 2 These criteria are consistent with those of Johnson et al. (2006a,b), who concluded that (1) biomass feedstocks should come first from wastes that would otherwise go to landfills, (2) agricultural residues should be harvested only when the needs for protecting soil from wind and water erosion and loss of soil organic carbon have been met, (3) dedicated fuel crops should
OCR for page 71
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Among the biomass sources considered are corn stover, straw from wheat and seed grasses (for example, bluegrass and fescue), traditional hay crops (for example, alfalfa and clover), normal and high-yielding fuel crops, woody residues, animal manure, and municipal solid waste. Advantages of and concerns about each of these feedstocks are described below. The resource amounts that could be made available by using technologies and management practices of 2008 and the resource amounts projected to be available by 2020 are also described. Corn Stover In 2007, 13.1 billion bushels of corn grain was harvested in the United States from 86.5 million acres of cropland. Assuming a 1:1 ratio of dry weight of corn grain to stover (Johnson et al., 2006a), the amount of stover produced was estimated to be 370 million tons. Not all the corn stover can be used to produce biofuel, however, because this crop residue is also a “resource” that farmers use to mitigate wind and water erosion and to maintain soil organic matter. The amount of stover that needs to be left on the land for those purposes depends on the tillage practice being used as soil is being prepared for planting by plowing, ripping, or turning (Johnson et al., 2006a; Wilhelm et al., 2007). Perlack et al. (2005) estimated that no-tillage requires 0.35–0.5 ton of stover per acre to protect against wind and water erosion, but that amount of crop residue is not sufficient to control soil erosion if more aggressive tillage is used (Figure 2.2) and is not sufficient to sustain soil organic matter (soil carbon). To maintain soil organic matter, 2.3–5.6 tons/acre needs to be left in the field, depending on crop rotation and tillage practice (Wilhelm et al., 2007). Maintaining soil organic matter is crucial for sustaining soil structure, water entry and retention, nutrient cycling, biological activity, and other critical soil processes. Erosion control and maintenance of soil organic matter are critical factors to be considered in the estimation of the sustainable amount of corn stover that could be harvested to produce biofuel. The national average corn-grain production in 2008 was 151 bushels/acre (USDA-NASS, 2008b). If erosion is to be controlled and soil organic matter maintained, the potential harvestable corn stover even with no-tillage practices is reduced from 3.58 tons/acre to 0.06–1.25 tons/acre depending on the crop rotation (Figure 2.2). If more intensive tillage be developed regionally to meet local needs, and (4) management strategies must ensure that soils do not lose their ability to provide food, feed, fiber, and fuel.
OCR for page 72
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts FIGURE 2.2 Tillage and crop-rotation effects on the amount of corn stover required to protect soil resources against wind or water erosion and to sustain soil carbon (organic matter) levels. Source: Adapted from Wilhelm et al., 2007. equivalent to moldboard plowing is used, as is the case for about 17 percent of U.S. corn cropland, all the corn stover in the corn–soybean rotation is required for maintenance of soil organic matter, and only 0.2 ton/acre would be available as a feedstock if corn is grown continuously. Using the higher harvestable value3 of 1.25 tons/acre and recognizing that only 70 percent of the available cropland area at most would be planted continuously in corn because of disease, insects, and other factors, the maximum sustainable amount of corn stover available as biofuel feedstock in 2007 would have been 75.7 million tons. That value, rounded to the nearest million tons, was used for the panel’s baseline estimate for the amount of corn stover that could be harvested sustainably. The panel’s projection of 112 million tons available by 2020 was calculated in a similar manner and allowed for increased yield as a result of genetic improvement and improved management. (See Appendix F for details of those estimates.) 3 The panel used the high harvestable value because it took a conservative approach to estimating the amount of stover that has to be left in the field to maintain soil.
OCR for page 73
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Wheat Straw and Seed-Grass Straw Wheat straw and grass straw can be biofuel feedstocks as the technology to convert them to liquid fuels develops. Banowetz et al. (2008) estimate that the Pacific Northwest states of Idaho, Oregon, and Washington could provide at least 6.5 million tons of crop residues with the wheat straw and grass straw yields in 2007 after the appropriate amount of wheat straw and grass straw are left on the field to protect soil resources. However, those straws are often distributed across the landscape at an average available density of about 1 ton/acre, so transporting them to centralized biomass-processing plants would probably increase transportation costs and transportation-dependent greenhouse gas releases. One approach for overcoming those limitations would be to establish localized preprocessing and densification centers. Similar estimates by Nelson (2002) for Kansas, Texas, Ohio, Illinois, and Missouri projected the availability of another 8.8 million tons of wheat straw for harvest from the Great Plains each year. The panel estimated that 15 million dry tons of wheat and grass straws per year could be available for fuel production on the basis of earlier studies. It assumed a 20 percent increase in available wheat and grass straws by 2020. Hay U.S. hay production ranged from about 50 million tons in 1999 to about 142 million tons in 2006 (USDA-NASS, 2008b). The average yield in 2007 was 2.4 tons/acre. Most hay is consumed as animal feed, but as with corn grain, average yields are often lower than many good producers achieve. On the basis of the 30-year record of increases in hay yields, the panel estimated that 10 percent of the average production for 2003–2007 (15 million tons) could be available for biofuel production without substantially affecting the hay price and supply. The portion of the hay crop used as biofuel feedstock was assumed to have very low nutritional quality for animal production because of excessive weathering. The low-quality hay would be marketed only in areas where biofuel plants provided an alternative marketing option to local farmers. The assumed supply of hay for use as a biofuel feedstock is small because hay production is dispersed, bulky, and expensive to transport. As with wheat and grass straws, the panel’s projection of available hay for biofuels in 2020 was based on a 20 percent yield increase as a result of better genetics and management practices.
OCR for page 106
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts REFERENCES Aden, A., M. Ruth, K. Ibsen, J. Jechura, K. Neeves, J. Sheehan, B. Wallace, L. Montague, A. Slayton, and J. Lukas. 2002. Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover. Golden, Colo.: National Renewable Energy Laboratory. Adler, P.R., S.J. Del Grosso, and W.J. Parton. 2007. Life-cycle assessment of net greenhouse gas flux for bioenergy cropping systems. Journal of Applied Ecology 17:675-691. Anderson, S.H., R.P. Udawatta, T. Seobi, and H.E. Garrett. 2009. Soil water content and infiltration in agroforestry buffer strips. Agroforestry Systems 75(1):5-16. Associated Press. 2008. Monsanto says its seeds will double yield of corn, soybeans and cotton by 2030. Available at http://www.iht.com/articles/ap/2008/06/04/business/NA-FIN-COM-USMonsanto-Future.php. Accessed March 4, 2009. Baker, T., I. Bashmakov, L. Bernstein, J.E. Bogner, P.R. Bosch, R. Dave, O.R. Davidson, B.S. Fisher, S. Gupta, K. Halsnaes, G.J. Heij, S. Kahn Ribeiro, S. Kobayashi, M.D. Levine, D.L. Martino, O. Masera, B. Metz, L.A. Meyer, G-J. Nabuurs, A. Najam, N. Nakicenovic, H.H. Rogner, J. Roy, J. Sathaye, R. Schock, P. Shukla, R.E.H. Sims, P. Smith, D.A. Tirpak, D. Urge-Vorsatz, and D. Zhou. 2007. Technical summary. In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, and L.A. Meyer, eds. New York: Cambridge University Press. Banowetz, G.M., A. Boatang, J.J. Steiner, S.M. Griffith, V. Sethi, and H. El-Nashaar. 2008. Assessment of straw biomass feedstock resources in the Pacific Northwest. Biomass and Bioenergy 32(7):629-634. Berdahl, J., A. Frank, J. Krupinsky, P. Carr, J. Hanson, and H. Johnson. 2005. Biomass yield, phenology, and survival of diverse switchgrass cultivars and experimental strains in western North Dakota. Agronomy Journal 97:549-555. Berry, J.K., J.A. Delgado, R. Khosla, and F.J. Pierce. 2003. Precision conservation for environmental sustainability. Soil and Water Conservation 58:332-339. Biomass Research and Development Board. 2008. Increasing Feedstock Production for Biofuels. Economic Drivers, Environmental Implications, and the Role of Research. Available at http://www.brdisolutions.com/Site%20Docs/Increasing%20Feedstock_revised.pdf. Accessed February 10, 2008. Blanco-Canqui, H., and R. Lal. 2007. Soil and crop response to harvesting corn residues for biofuel production. Geoderma 141:355-362. Bouton, J.H. 2007. Molecular breeding of switchgrass for use as a biofuel crop. Current Opinion in Genetic Development 17:553-558.
OCR for page 107
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Broussard, Whitney, and R. Eugene Turner. 2009. A century of changing land-use and water-quality relationships in the continental US. Frontiers in Ecology and the Environment 7(6):302-307. Brueggeman, R., N. Rostoks, D. Kudrna, A. Kilian, F. Han, J. Chen, A. Druka, B. Steffenson, and A. Kleinhofs. 2002. The barley stem rust-resistance gene Rpg1 is a novel disease-resistance gene with homology to receptor kinases. Proceedings of the National Academy of Sciences USA 99:9328-9333. Cameron, D. 2007. Rivals give Monsanto food for thought. Financial Times, September 4. Campbell, J.E., D.B. Lobell, R.C. Genova, and C.B. Field. 2008. The global potential of bioenergy on abandoned agriculture lands. Environmental Science and Technology 42:5791-5794. Cassman, K.G., and A.J. Liska. 2007. Food and fuel for all: Realistic or foolish? Biofuels, Bioproducts and Biorefining 1:18-23. Christian, D., A. Riche, and N. Yates. 2008. Growth, yield and mineral content of Miscanthus x Giganteus grown as a biofuel for 14 successful harvests. Industrial Crops and Products 28(3):320-327. Christian, D.G., N.E. Yates, and A. Riche. 2005. Establishing Miscanthus sinensis from seed using conventional sowing methods. Industrial Crops and Products 21(1):109-111. Coughenour, C.M., and S. Chamala. 2000. Conservation Tillage and Cropping Innovation: Constructing the New Culture of Agriculture. Ames: Iowa State University Press. Davidson, E.A., and I.L. Ackerman. 1993. Changes in soil carbon inventories following cultivation of previously untilled soils. Biogeochemistry 20:161-193. Dinnes, D.L. 2004. Assessments of Practices to Reduce Nitrogen and Phosphorus Nonpoint Source Pollution of Iowa’s Surface Waters. Iowa Department of Natural Resources and USDA-ARS National Soil Tilth Laboratory. Available at ftp://ftp.nstl.gov/pub/NPS/NPS%20Nutrient%20Pollution%20Assessments%20of%20Conservation%20Practices.pdf. Accessed April 25, 2008. Donner, S.D., and C.J. Kucharik. 2008. Corn-based ethanol production compromises goal of reducing nitrogen export by the Mississippi River. Proceedings of the National Academy of Sciences USA 105(11):4513-4518. Doornbosch, R., and R. Steenblik. 2007. Biofuels: Is the cure worse than the disease? In Round Table on Sustainable Development. Paris: Organisation for Economic Cooperation and Development. Duffy, M. 2007. Estimated Costs for Production, Storage, and Transportation of Switchgrass. Available at http://www.extension.iastate.edu/agdm/crops/pdf/a1-22.pdf. Accessed April 25, 2008. Edwards, William. 2007. Estimating a Value for Corn Stover. Available at http://www.extension.iastate.edu/agdm/crops/pdf/a1-70.pdf. Accessed April 25, 2008.
OCR for page 108
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts EIA (Energy Information Administration). 2008. Annual Energy Review 2007. DOE/EIA-0384(2007). Washington, D.C.: U.S. Department of Energy, Energy Information Administration. English, B.C., D.G. de la Torre Ugarte, K. Jensen, C. Hellwinckel, J. Menard, B. Wilson, R. Roberts, and M. Walsh. 2006. 25% Renewable Energy for the United States by 2025: Agricultural and Economic Impacts. University of Tennessee, Knoxville. Available at http://www.25x25.org/storage/25x25/documents/RANDandUT/UTEXECsummary25X25FINALFF.pdf. Accessed April 25, 2008. EPA (U.S. Environmental Protection Agency). 2007. Municipal Solid Waste Generation, Recycling, and Disposal in the United States: Facts and Figures for 2006. Available at http://www.epa.gov/epaoswer/nonhw/muncpl/pubs/msw06.pdf. Accessed April 25, 2008. Ernsting, A., and A. Boswell. 2007. Agrofuels: Towards a Reality Check in Nine Key Areas. Available at http://www.tni.org/reports/ctw/agrofuels.pdf. Accessed April 25, 2009. Fargione, J., J. Hill, D. Tilman, S. Polasky, and P. Hawthorne. 2008. Land clearing and the biofuel carbon debt. Science 319:1235-1238. Farrell, A., R. Plevin, B. Turner, A. Jones, M. O’Hare, and D. Kammen. 2006. Ethanol can contribute to energy and environmental goals. Science 311:506-509. Ferguson, R.B., G.W. Hergert, J.S. Schepers, C.A. Gotway, J.E. Cahoon, and T.A. Peterson. 2002. Site-specific management of irrigated maize: Yield and soil residual nitrate effects. Soil Science Society of America Journal 66:544-553. Field, C.B., J.E. Campbell, and D.B. Lobell. 2008. Biomass energy: The scale of the potential resource. Trends in Ecology and Evolution 23:65-72. Fight, R.D., and R.J. Barbour. 2005. Financial Analysis of Fuel Treatments. Portland, Oreg.: U.S. Department of Agriculture, Forest Service. Fike, J., D. Parrish, D. Wolf, J. Balasko, J. Green, Jr., M. Rasnake, and J. Reynolds. 2006. Long-term yield potential of switchgrass-for-biofuel systems. Biomass and Bioenergy 30(3):198-206. Firbank, Les G. 2008. Assessing ecological impacts of bioenergy projects. Bioenergy Research 1(1):12-19. Fornara, D.A., and D. Tilman. 2008. Plant functional composition influences rates of soil carbon and nitrogen accumulation. Journal of Ecology 96(2):314-322. French, B. 1960. Some considerations in estimating assembly cost functions for agricultural processing operations. Journal of Farm Economics 62:767-778. Giles, D.K., and D.C. Slaughter. 1997. Precision band sprayer with machine-vision guidance and adjustable yaw nozzles. Transactions of the American Society of Agricultural and Biological Engineers 40:29-36.
OCR for page 109
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Graham, R.L., and M.E. Walsh. 1999. A National Assessment of Promising Areas for Switchgrass, Hybrid Poplar, or Willow Energy Crop Production. Oak Ridge, Tenn.: Oak Ridge National Laboratory. Groom, M.J., E.M. Gray, and P.A. Townsend. 2007. Biofuels and biodiversity: Principles for creating better policies for biofuel production. Conservation Biology 22:602-609. Heaton, E., T. Voight, and S.P. Long. 2004a. A quantitative review comparing the yields of two candidate C4 perennial biomass crops in relation to nitrogen, temperature and water. Biomass and Bioenergy 27:21-30. Heaton, E.A., J. Clifton-Brown, T.B. Voight, M.B. Jones, and S.P. Long. 2004b. Miscanthus for renewable energy generation: European Union experience and projections for Illinois. Mitigation and Adaptation Strategies for Global Change 9:433-451. Heaton, E.A., F.G. Dohleman, and S.P. Long. 2008. Meeting US biofuel goals with less land: The potential of Miscanthus. Global Change Biology 14(9):2000-2014. Heggenstaller, A.H., R.P. Anex, M. Liebman, D.N. Sundberg, and L.R. Gibson. 2008. Productivity and nutrient dynamics in bioenergy double-cropping systems. Agronomy Journal 100:1740-1748. Hess, J.R., C.T. Wright, and K.L. Kenney. 2007. Cellulosic biomass feedstocks and logistics for ethanol production. Biomass, Bioproduction and Biorefining 1:181-190. Hill, J., E. Nelson, D. Tilman, S. Polasky, and D. Tiffany. 2006. Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels. Proceedings of the National Academy of Sciences USA 103(30):11206-11210. Hill, J., S. Polasky, E. Nelson, D. Tilman, H. Huo, L. Ludwig, J. Neumann, H. Zheng, and D. Bonta. 2009. Climate change and health costs of air emissions from biofuels and gasoline. Proceedings of the National Academy of Sciences USA 106:2077-2082. Hoskinson, R.L., D.L. Karlen, S.J. Birrell, C.W. Radtke, and W.W. Wilhelm. 2007. Engineering, nutrient removal, and feedstock conversion evaluations of four corn stover harvest scenarios. Biomass and Bioenergy 31:126-136. IPCC (Intergovernmental Panel on Climate Change). 2006. Guidelines for National Greenhouse Gas Inventories, Volume 4, Agriculture, Forestry and Other Land Use. Available at http://www.ipccnggip.iges.or.jp/public/2006gl/vol4.html. Accessed April 24, 2009. Johnson, J.M.F., R.R. Allmaras, and D.C. Reicosky. 2006a. Estimating source carbon from crop residues, roots, and rhizodeposits using the national grain-yield database. Agronomy Journal 98:622-636. Johnson, J.M.F., D. Reicosky, R. Allmaras, D. Archer, and W. Wilhelm. 2006b. A matter of balance: Conservation and renewable energy. Journal of Soil and Water Conservation 63:121-125.
OCR for page 110
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Johnson, J.M.F., M.D. Coleman, R.W. Gesch, A.A. Jaradat, R. Mitchell, D.C. Reicosky, and W.W. Wilhelm. 2007. Biomass-bioenergy crops in the United States: A changing paradigm. American Journal of Plant Science and Biotechnology 1(1):1-28. Kaliyan, N., and R.V. Morey. 2009. Factors affecting strength and durability of densified biomass products. Biomass and Bioenergy 33:337-359. Karlen, D.L., and S.J. Birrell. Unpublished. Crop Residue—What’s It Worth? U.S. Department of Agriculture and Iowa State University. Available at http://www1.eere.energy.gov/biomass/pdfs/Biomass_2009_Sustainabiliy_III_Karlen.pdf. Accessed April 25, 2009. Kaylen, M., D.L. Van Dyne, Y.S. Choi, and M. Blase. 2000. Economic feasibility of producing ethanol from lignocellulosic feedstocks. Bioresource Technology 72:19-32. Khanna, M., and B. Dhungana. 2007. Economics of Alternative Feedstocks in Corn-Based Ethanol in Illinois and the US: A Report from Department of Agricultural and Consumer Economics. Urbana-Champaign: University of Illinois. Available at http://www.farmdoc.uiuc.edu/policy/research_reports/ethanol_report/Ethanol%20Report.pdf. Accessed April 25, 2009. Khanna, M., B. Dhungana, and J. Clifton-Brown. 2008. Costs of producing Miscanthus and switchgrass for bioenergy in Illinois. Biomass and Bioenergy 32(6):482-493. Khosla, R., K. Fleming, J.A. Delgado, T.M. Shaver, and D.G. Westfall. 2002. Use of site-specific management zones to improve nitrogen management for precision agriculture. Journal of Soil and Water Conservation 57:513-518. Kumar, A., J. Cameron, and P. Flynn. 2003. Biomass power cost and optimum plant size in western Canada. Biomass and Bioenergy 24(6):445-464. Kumar, A., J. Cameron, and P. Flynn. 2005. Pipeline transport and simultaneous saccharification of corn stover. Bioresource Technology 96(7):819-829. Kumar, A., and S. Sokhansanj. 2007. Switchgrass (Panicum vigratum, L.) delivery to a biorefinery using Integrated Biomass Supply Analysis and Logistics (IBSAL) model. Bioresource Technology 98:1033-1044. Lal, R. 2007. Biofuels from crop residues. Soil and Tillage Research 93:237-238. Landis, D.A., M.M. Gardiner, W. van der Werf, and S.M. Swinton. 2008. Increasing corn for biofuel production reduces biocontrol services in agricultural landscapes. Proceedings of the National Academy of Sciences USA 105:20552-20557. Lewandowski, I., J. Scurlock, E. Lindvall, and M. Christou. 2003. The development and current status of perennial rhizomatous grasses as energy cops in the US and Europe. Biomass and Bioenergy 25(4):335-361. Liang, H.Y., C.J. Frost, X.P. Wei, N.R. Brown, J.E. Carlson, and M. Tien. 2008. Improved sugar release from lignocellulosic material by introducing a tyrosinerich cell wall pep-tide gene in poplar. CLEAN—Soil, Air, Water 36:662-668.
OCR for page 111
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Liebig, M.A., S.L. Kronberg, and J.R. Gross. 2008. Effects of normal and altered cattle urine on short-term greenhouse gas flux from mixed-grass prairie in the northern Great Plains. Agriculture Ecosystems and Environment 125:57-64. Low, S.A., and A.M. Isserman. 2009. Ethanol and the local economy: Industry trends, location factors, economic impacts, and risks. Economic Development Quarterly 23:71-88. Mapemba, L.D., F.M. Epplin, R.L. Huhnke, and C.M. Taliaferro. 2008. Herbaceous plant biomass harvest and delivery cost with harvest segmented by month and number of harvest machines endogenously determined. Biomass and Bioenergy 32(11)1016-1027. Mapemba, L., F. Epplin, C. Taliaferro, and R. Huhnke. 2007. Biorefinery feedstock production on conservation reserve program land. Review of Agricultural Economics 29(2):227-246. McAloon, A., F. Taylor, W. Yee, K. Ibsen, and R. Wooley. 2000. Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks. Golden, Colo.: National Renewable Energy Laboratory. McCarl, B., D. Adams, R. Alig, and J. Chmelik. 2000. Competitiveness of biomass fueled electrical power plants. Annals of Operations Research 94:37-55. McLaughlin, S.B., D.G. de la Torre Ugarte, C.T. Garten, Jr., L.R. Lynd, M.A. Sanderson, V.R. Tolbert, and D.D. Wolf. 2002. High-value renewable energy from prairie grasses. Environmental Science and Technology 36:2122-2129. McLaughlin, S.B., and L.A. Kszos. 2005. Development of switchgrass (Panicum virgatum) as a bioenergy feedstock in the United States. Biomass and Bioenergy 28:515-535. Meksem, K., E. Ruben, D. Hyten, M. Schmidt, and D.A. Lightfoot. 2001. High-throughput detection of polymorphism physically linked soybean cyst nematode resistance gene Rhg4 using Taqman probes. Molecular Breeding 7:63-71. Milbrandt, A. 2005. A geographic perspective on the current biomass resource availability in the United States. Available at http://www.osti.gov/bridge. Accessed November 9, 2008. Monti, A., S. Fazio, and G. Venturi. 2009. The discrepancy between plot and field yields: Harvest and storage losses of switchgrass. Biomass & Bioenergy 33(5):841-847. Morey, R.V., D. Tiffany, and D. Hatfield. 2005. Biomass for Electricity and Process Heat at Ethanol Plants. St. Joseph, Mich: American Society for Agricultural and Biological Engineers. Murray, B.C., B.A. McCarl, and H.C. Lee. 2004. Estimating leakage from forest carbon sequestration programs. Land Economics 80:109-124. Myers, N., and J. Kent. 2003. New consumers: The influence of affluence on the environment. Proceedings of the National Academy of Sciences USA 100:4963-4968. NBB (National Biodiesel Board). 2008. U.S. Biodiesel Production Capacity. Jefferson City, Mo.: NBB.
OCR for page 112
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts NCGA (National Corn Growers Association). 2008. World of Corn. Chesterfield, Mo.: NGCA. Nelson, R.G. 2002. Resource assessment and removal analysis for corn stover and wheat straw in the eastern and midwestern United States: Rainfall and wind-induced soil erosion methodology. Biomass and Bioenergy 22:349-363. NRC (National Research Council). 1989. Alternative Agriculture. Washington, D.C.: National Academy Press. NRC. 2008a. Achievements of the National Plant Genome Initiative and New Horizons in Plant Biology. Washington, D.C.: The National Academies Press. NRC. 2008b. Water Implications of Biofuels Production in the United States. Washington, D.C.: The National Academies Press. Perlack, R., and A. Turhollow. 2002. Assessment of Options for the Collection, Handling, and Transport of Corn Stover. Oak Ridge, Tenn.: Oak Ridge National Laboratory. Perlack, R., and A. Turhollow. 2003. Feedstock cost analysis of corn stover residues for further processing. Energy 28:1395-1403. Perlack, R.D., L.L. Wright, A.F. Turhollow, R.L. Graham, B.J. Stokes, and D.C. Erbach. 2005. Biomass as feedstock for a bioenergy and bioproducts industry: The technical feasibility of a billion-ton annual supply. Washington, D.C.: U.S. Department of Agriculture and U.S. Department of Energy. Perrin, R., K. Vogel, M. Schmer, and R. Mitchell. 2008. Farm-scale production cost of switchgrass for biomass. BioEnergy Research 1(1):91-97. Petrolia, D.R. 2008. The economics of harvesting and transporting corn stover to fuel ethanol: A case study for Minnesota. Biomass and Bioenergy 32(7):603-612. Pineiro, G., E.G. Jobbagy, J. Baker, B.C. Murray, and R.B. Jackson. 2009. Set-asides can be better climate investment than corn ethanol. Ecological Applications 19:277-282. Raghu, S., R.C. Anderson, C.C. Daehler, A.S. Davis, R.N. Wiedenmann, D. Simberloff, and R.N. Mack. 2006. Adding biofuels to the invasive species fire? Science 313:1742. Reijnders, L. 2004. Conditions for the sustainability of biomass based fuel use. Energy Policy 34:863-876. Rice Chromosomes 11 and 12 Sequencing Consortia. 2005. The sequence of rice chromosomes 11 and 12, rich in disease resistance genes and recent gene duplications. BMC Biology 3:20. Robert, P.C. 2002. Precision agriculture: A challenge for crop nutrition management. Plant and Soil 247:143-149. Robertson, G.P, V.H. Dale, O.C. Doering, S.P. Hamburg, J.M. Melillo, M.M. Wander, W.J. Parton, P.R. Adler, J.N. Barney, R.M. Cruse, C.S. Duke, P.M. Fearnside, R.F. Follett, H.K. Gibbs, J. Goldemberg, D.J. Mladenoff, D. Ojima, M.W. Palmer, A. Sharpley, L. Wallace, K.C. Weathers, J.A. Wiens, and W.W. Wilhelm. 2008. Sustainable biofuels redux. Science 322:49.
OCR for page 113
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Schilling, K.E., M.K. Jha, Y-K. Zhang, P.W. Gassman, and C.F. Wolter. 2008. Impact of land use and land cover change on the water balance of a large agricultural watershed: Historical effects and future directions. Water Resources Research 44: W00A09. Schlesinger, W.H. 1997. Biogeochemistry: An Analysis of Global Change. 2nd ed. San Diego, Calif.: Academic Press. Schmer, M.R., K.P. Vogel, R.B. Mitchell, L.E. Moser, K.M. Eskridge, and R.K. Perrin. 2006. Establishment stand thresholds for switchgrass grown as a bioenergy crop. Crop Science 46:157-161. Schmer, M.R., K.P. Vogel, R.B. Mitchell, and R.K. Perrin. 2008. Net energy of cellulosic ethanol from switchgrass. Proceedings of the National Academy of Sciences USA 105:464-469. Searchinger, T., R. Heimlich, R.A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, S. Tokgoz, D. Hayes, and T-H. Yu. 2008. Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land use change. Science 319:1238-1240. Searcy, E., P. Flynn, E. Ghafoori, and A. Kumar. 2007. The relative cost of biomass energy transport. Applied Biochemistry and Biotechnology 137-140(1-12):639-652. Secchi, S., and B.A. Babcock. 2007. Impact of high crop prices on environmental quality: A case of Iowa and the Conservation Reserve Program. Ames: Iowa State University. Available at http://www.card.iastate.edu/publications/DBS/PDFFiles/07wp447.pdf. Accessed April 25, 2009. Shinners, K.J., G.C. Boettcher, R.E. Muck, P.J. Weimer, M.D. Casler. 2006. Drying, harvesting, and storage characteristics of perennial grasses as biomass feedstocks. ASABE Paper No. 061012. St. Joseph, Mich.: American Society of Agricultural and Biological Engineers. Skinner, J.S., J. von Zitzewitz, L. Marquez-Cedillo, T. Filichkin, P. Szücs, K. Amundsen, E.J. Stockinger, M.F. Thomashow, T.H.H. Chen, and P.M. Hayes. 2005. Barley contains a large cbf gene family associated with quantitative cold tolerance traits. In Advances in Plant Cold Hardiness: Molecular Genetics and Transgenics, T.H.H. Chen, M. Uemura, and S. Fujikawa, eds. Oxon, United Kingdom: CAB International. Sokhansanj, S., and A. Turhollow. 2002. Baseline cost for corn stover collection. Applied Engineering and Agriculture 18:525-530. Stevenson, F.J. 1994. Humic Chemistry: Genesis, Composition, Reactions. 2nd ed. New York: Wiley. Summit Ridge Investments, LLC. 2007. Eastern Hardwood Forest Region Woody Biomass Energy Opportunity. Granville, Vt: Summit Ridge Investments. Suzuki, Y. 2006. Estimating the Cost of Transporting Corn Stalks in the Midwest. Ames: Iowa State University College of Business, Business and Partnership Development. Tian, L., J.F. Reid, and J.W. Hummel. 1999. Development of a precision sprayer for site-specific weed management. Transactions of the ASABE 42:893-900.
OCR for page 114
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts Tilman, D., J. Hill, and C. Lehman. 2006. Carbon-negative biofuels from low-input high diversity grassland biomass. Science 314:1598-1600. U.S. Census Bureau. 2008. Projections of the Population and Components of Change for the United States: 2010 to 2050. Washington, D.C.: U.S. Census Bureau. USDA-FSA (U.S. Department of Agriculture, Farm Service Agency). 2008a. Conservation Reserve Program: Summary and Enrollment Statistics—Fiscal Year 2007. Washington, D.C.: USDA-FSA. USDA-FSA. 2008b. Conservation Reserve Program: Monthly Summary—June 2008. Washington, D.C.: U.S. Department of Agriculture. USDA-NASS (U.S. Department of Agriculture, National Agricultural Statistics Service). 2007a. Agricultural Prices 2006 Summary. Washington, D.C.: U.S. Department of Agriculture, National Agricultural Statistics Service. USDA-NASS. 2007b. Agricultural Prices December 2007. Washington, D.C.: U.S. Department of Agriculture, National Agricultural Statistics Service. USDA-NASS. 2008a. Quick Stats. Available at http://www.nass.usda.gov/QuickStats/PullData_US.jsp. Accessed October 6, 2008. USDA-NASS. 2008b. Crops and Plants. Available at http://www.nass.usda.gov. Accessed August 22, 2008. USDA-NRCS (U.S. Department of Agriculture, Natural Resources Conservation Service). 2003. Costs Associated with Development and Implementation of Comprehensive Nutrient Management Plans. Part I: Nutrient Management, Land Treatment, Manure and Wastewater Handling and Storage, and Recordkeeping. Available at http://www.nrcs.usda.gov/technical/NRI/pubs/cnmp1full.pdf. Accessed October 13, 2008. Vadas, P.A., K.H. Barnett, and D.J. Undersander. 2008. Economics and energy of ethanol production from alfalfa, corn, and switchgrass in the upper Midwest, USA. BioEnergy Research 1:44-55. Vogel, K. 2007. Switchgrass for Biomass Energy: Status and Progress. Available at http://ageconsearch.umn.edu/bitstream/8030/1/fo07vo01.pdf. Accessed March 2, 2009. Vogel, K., J. Brejda, D. Walters, and D. Buxton. 2002. Switchgrass biomass production in the Midwest USA: Harvest and nitrogen management. Agronomy Journal 94:413-420. Wang, M., W. May, and H. Huo. 2007. Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types. Environmental Research Letters 2:1-9. Wilhelm, W.W., J.M-F. Johnson, D.L. Karlen, and D.T. Lightle. 2007. Corn stover to sustain soil organic carbon further constrains biomass supply. Agronomy Journal 99:1665-1667. Wu, M., Y. Wu, and M. Wang. 2006. Energy and emissions benefits of alternative transportation liquid fuels derived from switchgrass: A fuel life cycle assessment. Biotechnology Progress 22(4):1012-1024.
OCR for page 115
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts York News-Times. 2009. Seed companies look to increase corn yields. Available at http://www.yorknewstimes.com/articles/2009/02/04/news/doc49891c8e093e3392930640.txt. Accessed March 4, 2009. Zhang, N., M. Wang, and N. Wang. 2002. Precision agriculture—A worldwide overview. Computers and Electronics in Agriculture 36:113-132.
OCR for page 116
Liquid Transportation Fuels from Coal and Biomass: Technological Status, Costs, and Environmental Impacts This page intentionally left blank.