The National Academies Press

Currently Skimming:

Pages 181-262

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 181... ... 5 Environmental Effects and Tradeoffs of Biofuels P etroleum extraction, transport, reﬁning, and combustion have many known negative environmental effects, including disruption of sensitive ecological habitats and high greenhouse-gas (GHG) emissions. Read the entire page →
From page 182... ... 182 RENEWABLE FUEL STANDARD contributes to uncertainty in assessing environmental effects, are also pointed out in the following areas: • GHG emissions • Air quality • Water quality • Water quantity and consumptive use • Soil • Biodiversity • Ecosystem services • It uses regional environmental assessments of biofuel production as an illustration because the effects of biofuel production are location-speciﬁc, and conclusions drawn from regional environmental assessments could differ from an assessment of cumulative effects across the nation. • It discusses opportunities to minimize negative environmental effects at the end of the chapter. Read the entire page →
From page 183... ... 183 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS less of this pollutant than gasoline" are by themselves meaningless and often misleading unless the goal and scope of the study cited in support of this statement are presented. (See Box 5-1 for a description of the importance of care when reporting results from LCA studies.) Read the entire page →
From page 185... ... 185 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS GREENHOUSE-GAS EMISSIONS Feedstock Production One of the most debated topics surrounding the environmental effect of biofuels is the net GHG emissions from producing various feedstocks. Potential GHG emissions from bioenergy feedstock production include carbon dioxide (CO2) Read the entire page →
From page 186... ... 186 RENEWABLE FUEL STANDARD (Robert, 2002; Lamb et al., 2008; USDA-NIFA, 2009) Read the entire page →
From page 187... ... 187 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS sample results involving the minimization of GHG ﬂux per unit area, although the ﬂexibility of their framework allows for the calculation of other variables of interest, such as GHG ﬂux per unit of energy produced, which may be more useful for integration with full LCAs. In addition, Zhang et al. Read the entire page →
From page 188... ... 188 RENEWABLE FUEL STANDARD Growing perennial dedicated bioenergy crops could have less direct GHG emissions than growing row crops because their root systems contribute to sequestration of carbon. Surveys of common agronomic practices for growing Miscanthus show a broad range in nitrogen fertilizer use, typically around 50-100 lbs per acre per year (Heaton et al., 2004; Khanna et al., 2008) Read the entire page →
From page 189... ... 189 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS commodity crops and raise prices, thus triggering other agricultural growers to respond to market signals (higher commodity prices) and to expand production of the displaced commodity crop. Read the entire page →
From page 190... ... 190 RENEWABLE FUEL STANDARD competing demands for land, as well as the supply of land. A number of different economic models, including general-equilibrium and partial-equilibrium models, have been used to study indirect land changes, and the advantages and disadvantages of several approaches have been discussed elsewhere (Kretschmer and Peterson, 2010) Read the entire page →
From page 191... ... 191 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS brought into production. The results from Hertel et al. Read the entire page →
From page 192... ... 192 RENEWABLE FUEL STANDARD of simulations but assumed that during the time period of 2006-2015, population and crop yields would continue to grow. They estimated that the average land requirement for the incremental ethanol production was 0.32 acres of land to produce 1,000 gallons of ethanol. Read the entire page →
From page 193... ... TABLE 5-2 GHG Emissions from Market-Mediated Indirect Land-Use Changes as a Result of Expanding Corn-Grain Ethanol Production in the United States Estimated by Various Authors Economic GHG emissions models used from indirect Increase to estimate land-use in ethanol market- Land-cover change production mediated change data Emission (million (g CO2eq per effects used factors used MJ) Target year liters) Read the entire page →
From page 194... ... TABLE 5-2 Continued 194 Economic GHG emissions models used from indirect Increase to estimate land-use in ethanol market- Land-cover change production mediated change data Emission (million (g CO2eq per effects used factors used MJ) Target year liters) Read the entire page →
From page 195... ... 195 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS actual land changes and their relation to increasing biofuel production in the United States will only be observed as markets adjust to increased biofuel production. Even with longterm empirical data on land-use and land-cover changes, measurements of associated GHG emissions, and data on agricultural markets, estimating the global GHG beneﬁts or emissions from U.S. Read the entire page →
From page 196... ... 196 RENEWABLE FUEL STANDARD in CO2 emissions from a bioreﬁnery that converts corn stover to ethanol biochemically compared to one that converts wood chips to ethanol thermochemically are estimated to be small (Foust et al., 2009; NAS-NAE-NRC, 2009) , particularly when they are compared to variations in CO2 emissions in other parts of the fuel production life cycle. Read the entire page →
From page 199... ... 199 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-3 Published Estimates of and Some Assumptions Used in Estimating LifeCycle Greenhouse-Gas (GHG) Emissions of Corn-Grain Ethanol Life-cycle GHG Region for which the Indirect land-use (g CO2 eq per MJ) Read the entire page →
From page 200... ... 200 RENEWABLE FUEL STANDARD FIGURE 5-3 Probability distributions for U.S. industry greenhouse-gas (GHG) Read the entire page →
From page 201... ... 201 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-4 Greenhouse-gas (GHG) Emissions from Corn-Grain Ethanol Relative to Gasoline as Determined by EPA in Its Final Rule for RFS2 Dried distillers grain with Bioreﬁnery Heat Source solubles (DDGS) Read the entire page →
From page 202... ... 202 RENEWABLE FUEL STANDARD Biofuels from Dedicated Energy Crops The use of herbaceous and woody dedicated energy crops for biofuels could lower or raise GHG emissions depending on how and where these crops are grown. If land already in food crop production or in pasture is converted to dedicated energy crops, the resulting carbon debt from market-mediated effects might be sufﬁciently high to offset any carbon savings otherwise realized (Roberts et al., 2010) Read the entire page →
From page 203... ... 203 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS • Data and estimates of market-mediated effects of land use, commodity markets, and energy markets over time; and • Information on the extent to which the introduction of new biofuels into fuel mar kets displaces petroleum-based fuel production, so as to verify the assumption of complete displacement of petroleum-based fuel by biofuels used in attributional LCAs. In preparing a complete LCA for assessing the future effects of achieving RFS2 on global GHG emissions, two sets of scenarios have to be evaluated and compared with each other. Read the entire page →
From page 204... ... 204 RENEWABLE FUEL STANDARD TABLE 5-5 Average Percent Change in Tailpipe Emissions Compared to a Reference Fuel Containing No Ethanol E10 E85 Nonmethane hydrocarbons (NMHCs) +9 –48 NDa Nonmethane organic gas +14 Acetaldehyde +108 +2540 1,3-Butadiene +16 –77 Benzene +15 –76 NDa Nitrous oxides (NOx) Read the entire page →
From page 206... ... 206 RENEWABLE FUEL STANDARD FIGURE 5-5 Human health damage costs (dollars per gallon of gasoline equivalent) of life-cycle air-quality impacts of gasoline, corn-grain ethanol, and cellulosic ethanol. Read the entire page →
From page 207... ... 207 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-6 Nationwide Emission Inventories for 2022 for the Renewable Fuel Standard (RFS) Read the entire page →
From page 208... ... 208 RENEWABLE FUEL STANDARD The qualitative effects of growing bioenergy feedstocks are not different than existing agriculture for the same crops. If growing bioenergy feedstocks increases the extent of agriculture of annual crops within a given basin, it could cause greater effects on water quality. Read the entire page →
From page 209... ... 209 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Models to assess the effects of changes in land use and stream or lake quality are many, and they differ in their goals, assumptions, approaches, complexity, and amount of input data required to analyze the problem. Some of the leading watershed and stream models include the Soil and Water Assessment Tool (SWAT, USDA) Read the entire page →
From page 210... ... 210 RENEWABLE FUEL STANDARD represents 5 to 10 percent of the nitrogen applied to corn and a signiﬁcant economic loss for the farmer. But it also impairs downstream uses all the way from the farm to its ultimate discharge in the Gulf of Mexico. Read the entire page →
From page 211... ... 211 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-7 Net Change in Flow-Normalized Nitrate Concentration and Flux Between 1980 and 2008 Flow-Normalized Concentration of Nitrate as N Flow-Normalized Flux of Nitrate as N Total Annual Flow Normalized Annual Total Yield (Flux Mean Flow- Annual Flow- Per Unit Normalized Normalized Area) in Change, Concentration Change, 1980- Change, Flux in 1980, 1980 (kg/ 1980-2008, Change, 108 kg/yr km2/yr) Read the entire page →
From page 212... ... 212 RENEWABLE FUEL STANDARD estimate the effect of increasing biofuel production as a result of RFS2, as their baseline scenario is no ethanol production. Before RFS went into effect in 2005, 3.9 billion gallons of ethanol were produced. Read the entire page →
From page 213... ... 213 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-8 Application Rates onto Land for Nitrogen, Phosphorus, and Pesticides (and Soil Erosion) as a Result of Growing Corn as Feedstock for Ethanol Production Nitrogen (N) Read the entire page →
From page 214... ... 214 RENEWABLE FUEL STANDARD ﬂoodplain alluvial soils to corn than from upland sloped soils, so the location of the land conversion within the watershed is important (Schilling and Wolter, 2008) Read the entire page →
From page 215... ... 215 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Conversion to Fuels Waste streams from ethanol distilling plants include salts, which are formed by scaling and evaporation in the cooling towers and boilers. If these deposits are not removed (a process called "blow down") Read the entire page →
From page 216... ... 216 RENEWABLE FUEL STANDARD TABLE 5-9 Compositional Analysis of Two Ethanol Plant Discharges Adapted from NRC 2008 Siouxland Ethanol Facility Little Sioux Ethanol Facility (Sioux Center, Iowa) Simulated Blowdown Big Sioux Constituent, mg/L (oz/gallon × 10–3) Read the entire page →
From page 217... ... 217 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS in environmental assessments of planned cellulosic bioreﬁneries (DOE, 2005; ENSR AECOM, 2008; DOE-EERE, 2010b) Read the entire page →
From page 219... ... 219 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS FIGURE 5-8 U.S. irrigation corn for grain. Read the entire page →
From page 221... ... 221 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-10 Comparison of Water Requirements for Ethanol Production from Corn Grain, Sugarcane, and Other Potential Energy Crops Crop Water requirements, Biofuel conversion, L Crop water Crop water m3 water/Mg crop fuel/Mg crop requirement for requirement per unit biofuel, m3 water/ energy, m3 water/GJ (gallons water/ton) (gallons fuel/ton crop) Read the entire page →
From page 222... ... 222 RENEWABLE FUEL STANDARD itself includes evaporative losses from cooling tower circulation and during the drying process for stillage. Water use for biodiesel reﬁneries includes water used in processing the feedstock, separation of products and coproducts, and conditioning. Read the entire page →
From page 223... ... 223 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS FIGURE 5-10 Ethanol bioreﬁneries superimposed on a map of the major bedrock aquifers and their water usage rates. Read the entire page →
From page 224... ... 224 RENEWABLE FUEL STANDARD volumes. Because much water is lost by evaporation in bioreﬁneries, development and implementation of new technologies to reduce evaporative loss from processing biomass to fuel provide opportunities to reduce consumptive water use in bioreﬁneries (Huffaker, 2010) Read the entire page →
From page 225... ... 225 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS diesel, or electricity used for farming, but those water inputs are small proportions of the life-cycle water use (King and Webber, 2008; Harto et al., 2010) Read the entire page →
From page 226... ... 226 RENEWABLE FUEL STANDARD TABLE 5-12 Embodied Water in Ethanol (EWe) and Total Consumptive Water Use (TCW) Read the entire page →
From page 227... ... 227 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS TABLE 5-13 Consumptive Water Use over the Life Cycle of Biofuel and PetroleumBased Fuel Production Estimated by Different Studies Life-cycle consumptive water use, gallons of water per gallon of gasoline equivalent Reference Corn-grain ethanol Switchgrass ethanol Petroleum-based fuel 1500 923-1307 Not estimated Fingerman et al., 2010 1.9-5.9a 42-640 2.9-640 Harto et al., 2010 1.4-2.9a 62-2400 Not estimated King and Webber, 2008 3.4-6.6b 15-490 2.9-15 Wu et al. 2009 aPetroleum-based fuel considered is conventional gasoline. Read the entire page →
From page 228... ... 228 RENEWABLE FUEL STANDARD include management practices in feedstock production, feedstock and residue removal, and discharges from conversion to fuels. Feedstock Production Among the key debates associated with biofuel production are the net effects of feedstock production on ecosystem carbon storage, particularly with respect to soil carbon storage. Read the entire page →
From page 229... ... 229 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS threshold (Van Groenigan et al., 2010) (see also "Water Quality" section above) Read the entire page →
From page 230... ... 230 RENEWABLE FUEL STANDARD lead to a decline in biodiversity (GAO, 2009) Read the entire page →
From page 231... ... 231 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS and 1.5 million acres of land that are not suitable for crop production. In addition, some acreage of herbaceous perennial grasses for biofuels is likely to be managed monoculture, which is likely to support lower diversity than a mixed grass stand. Read the entire page →
From page 232... ... 232 RENEWABLE FUEL STANDARD reviewed 25 studies involving manipulations of CWD (that is, removed or added downed woody debris and snags) and found that diversity and abundance of cavity-nesting and open-nesting birds and of invertebrates were substantially and consistently lower in treatments with less CWD. Read the entire page →
From page 233... ... 233 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS biodiversity could be affected by land-cover change, associated with bioenergy feedstock production. Monitoring of land-cover change, including identifying land taken out of CRP that was subsequently used for producing bioenergy feedstocks, would help identify and assess any effects of increasing biofuel production on biodiversity. Read the entire page →
From page 234... ... 234 RENEWABLE FUEL STANDARD FIGURE 5-11 Conceptual framework for comparing tradeoffs of ecosystem services under different land uses. NOTE: "The provisioning of multiple ecosystem services under different land-use regimes can be illustrated with these simple ‘ﬂower' diagrams, in which the condition of each ecosystem service is indicated along each axis. Read the entire page →
From page 235... ... 235 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS comprehensive estimates at national and international scales are necessary to inform decision-making. In addition, an individual bioreﬁnery might have localized environmental effects that are not of concern beyond the local scale. Read the entire page →
From page 236... ... 236 RENEWABLE FUEL STANDARD Direct Facility Effects DOE judged that impacts from construction and operation of the cellulosic biofuel facility in Emmetsburg, Iowa, would not exceed national or local environmental standards, including those requiring accounting for social effects. There would be positive effects on employment (ENSR AECOM, 2008) Read the entire page →
From page 237... ... 237 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS with all environmental assessments, there could be unique circumstances including special issues associated with soil erosion, water supplies, or wildlife that vary from one location to another within the region. Feedstocks The proposed Abengoa facility would initially use cellulosic biomass consisting primarily of corn and grain-sorghum stover and wheat straw produced principally or primarily on farmland classiﬁed as highly productive, with some residues from lower classiﬁed soils (DOE-EERE, 2010b) Read the entire page →
From page 238... ... 238 RENEWABLE FUEL STANDARD FIGURE 5-12 Average 2004-2006 saturated thickness for the High Plains Aquifer in Kansas. Read the entire page →
From page 239... ... 239 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS FIGURE 5-13 Usable lifetime of the High Plains Aquifer in Kansas estimated on the basis of groundwater trends from 1996 to 2006 and the minimum saturated requirements to support well yields of 400 gallons per minute under a scenario of 90 days of pumping with wells on ¼ sections. Read the entire page →
From page 240... ... 240 RENEWABLE FUEL STANDARD conversion process developed by the Inbicon Company of Denmark. An environmental assessment has not been conducted for cellulosic biofuel production. Read the entire page →
From page 241... ... 241 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS North Central Region Feedstocks The Northern Hardwoods Sugar Maple-Beech-Birch community of forests extends from Northern Minnesota through New England and into Maine (Covington, 1980; Drever et al., 2008) Read the entire page →
From page 242... ... 242 RENEWABLE FUEL STANDARD technical advances can affect realized yields in speciﬁc locations and result in annual and year-to-year variability (Easterling et al., 2007) Read the entire page →
From page 244... ... 244 RENEWABLE FUEL STANDARD Determining best management practices for the production of different feedstock types in various regions and developing sustainability standards or certiﬁcation processes could provide opportunities to enhance environmental beneﬁts and minimize negative environmental effects. Therefore, the national and international community has been working to select a set of indicators that can be used to measure the environmental effects of increased biofuel production. Read the entire page →
From page 245... ... 245 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS CONCLUSION The environmental effects of biofuel production in the United States can be discussed in several contexts. For example, one context includes mitigating the net environmental costs; this chapter provides many speciﬁc examples of how biofuel production could result in positive, neutral, or negative environmental outcomes depending on the particular environmental effect of concern, the crop used, the land used to cultivate the crop and its prior use, the management practices used, and other factors including environmental effects from market-mediated land-use and land-cover changes. Read the entire page →
From page 246... ... 246 RENEWABLE FUEL STANDARD United States that would result in net GHG emissions, the policy cannot prevent marketmediated effects on land-use or land-cover changes nor can it control land-use changes outside the United States. Therefore, the extent to which RFS2 contributes to lowering global GHG emissions is uncertain. Read the entire page →
From page 247... ... 247 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Soil Quality Whether the environmental effects on soil quality are positive or negative depend, in large part, on the feedstock grown, prior condition of the land, and management practices used. Overharvesting of crop or forest residues can certainly have negative effects on soil quality. Read the entire page →
From page 248... ... 248 RENEWABLE FUEL STANDARD Adams, D.M., R.W. Haynes, and A.J. Read the entire page →
From page 249... ... 249 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Bouwman, A.F., I Read the entire page →
From page 250... ... 250 RENEWABLE FUEL STANDARD Cassman, K.G., S Read the entire page →
From page 251... ... 251 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS DOE-EERE (U.S. Department of Energy - Energy Efﬁciency and Renewable Energy) Read the entire page →
From page 252... ... 252 RENEWABLE FUEL STANDARD Evans, A.M., R.T. Perschel, and B.A. Read the entire page →
From page 253... ... 253 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Geist, H.J., and E.F. Lambin. Read the entire page →
From page 254... ... 254 RENEWABLE FUEL STANDARD Hochman, G., D Rajagopal, and D Read the entire page →
From page 255... ... 255 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Khanna, M., B Dhungana, and J Read the entire page →
From page 256... ... 256 RENEWABLE FUEL STANDARD Liu, Y., M.A. Evans, and D Read the entire page →
From page 257... ... 257 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Murray, B.C., B Sohngen, and M.T. Read the entire page →
From page 258... ... 258 RENEWABLE FUEL STANDARD Overmars, K.P., E Stehfest, J.P.M. Read the entire page →
From page 259... ... 259 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS Reitz, S.R., G.S. Read the entire page →
From page 260... ... 260 RENEWABLE FUEL STANDARD Shi, A.Z., L.P. Read the entire page →
From page 261... ... 261 ENVIRONMENTAL EFFECTS AND TRADEOFFS OF BIOFUELS UNL (University of Nebraska, Lincoln) Read the entire page →
From page 262... ... 262 RENEWABLE FUEL STANDARD West, T.O., C.C. Brandt, L.M. Read the entire page →

From page 181...

... 5 Environmental Effects and Tradeoffs of Biofuels P etroleum extraction, transport, reﬁning, and combustion have many known negative environmental effects, including disruption of sensitive ecological habitats and high greenhouse-gas (GHG) emissions.