Sugarcane ethanol: Contributions to climate change - BAFF

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Chapter 7 Industrial interest in those areas comes from the energy sector, biotechnology as well as chemical industry. Given the policy targets on (second generation) biofuels in North America and the EU, high oil prices and increased pressure to secure sustainable production of biofuels (e.g. avoiding con�icts with food production and achieve high reduction in GHG emissions), pressure on both the market and policy to commercialize those technologies is high. When turn-key processes are available is still uncertain, but such breakthroughs may be possible already around 2010. 4. Energy and greenhouse gas balances of biofuels 4.1. Energy yields �e energy yield per unit of land surfaces resources depends to a large extent on the crop choice and the e�ciency of the entire energy conversion route from ‘crop to drop’. �is is illustrated by the �gures in Table 2. It is important to stress that when lignocellulose is the feedstock of choice production is not constrained to arable land, but amounts to the sum of residues and production from degraded/marginal lands not used for current food production. Ultimately, this will be the preferred option in most cases. Table 2. Indicative ranges for biomass yield and subsequent fuel production per hectare per year for different cropping systems in different settings. Starch and sugar crops assume conversion via fermentation to ethanol and oil crops to biodiesel via esterification (commercial technology at present). The woody and grass crops require either hydrolysis technology followed by ethanol or gasification to syngas to produce synthetic fuel (both not yet commercial conversion routes). Crop Biomass yield (odt/ha/yr) Wheat 4-5 ~50 Maize 5-6 ~60 Sugar beet 9-10 ~110 Soy bean 1-2 ~20 Sugarcane 5-20 ~180 Palm oil 10-15 ~160 Jathropha 5-6 ~60 SRC temperate climate 10-15 100-180 SRC tropical climate 15-30 170-350 Energy grasses good conditions 10-20 170-230 Perennials marginal/degraded lands 3-10 30-120 Energy yield in fuel (GJ/ha/yr) 172 Sugarcane ethanol
4.2. Greenhouse gas balances Biofuel conversion technologies �e net emissions over the full life cycle of biofuels – from changes in land use to combustion of fuels – that determine their impact on the climate. Research on net emissions is far from conclusive, and estimates vary widely. Calculations of net GHG emissions are highly sensitive to assumptions about system boundaries and key parameter values – for example, land use changes and their impacts, which inputs are included, such as energy embedded in agricultural machinery and how various factors are weighted. �e primary reasons for di�ering results are di�erent assumptions made about cultivation, and conversion or valuation of co-products. (Larson, 2005), who reviewed multiple studies, found that the greatest variations in results arose from the allocation method chosen for co-products, and assumptions about N 2 O emissions and soil carbon dynamics. In addition, GHG savings will vary from place to place – according to existing incentives for GHG reductions, for example. And the advantages of a few biofuels (e.g. sugarcane ethanol in Brazil) are location speci�c. As a result, it is di�cult to compare across studies; however, despite these challenges, some of the more important studies point to several useful conclusions. �is analysis notwithstanding, the vast majority of studies have found that, even when all fossil fuel inputs throughout the life cycle are accounted for, producing and using biofuels made from current feedstock result in substantial reductions in GHG emissions relative to petroleum fuels. In general, of all potential feedstock options, producing ethanol from maize results in the smallest decrease in overall emissions. �e greatest bene�t, meanwhile, comes from ethanol produced from sugarcane grown in Brazil (or from using cellulose or wood waste as feedstock). Several studies have assessed the net emissions reductions resulting from sugarcane ethanol in Brazil, and all have concluded that the bene�ts far exceed those from grain-based ethanol produced in Europe and the United States. Fulton (2004) attributes the lower life-cycle climate impacts of Brazilian sugarcane ethanol to two major factors: First, cane yields are high and require relatively low inputs of fertilizer, since Brazil has better solar resources and high soil productivity. Second, almost all conversion plants use bagasse (the residue that remains a�er pressing the sugar juice from the cane stalk) for energy, and many recent plants use co-generation (heat and electricity), enabling them to feed electricity into the grid. As such, net fossil energy requirements are near zero, and in some cases could be below zero. (In addition, less energy is required for processing because there is no need for the extra step to break down starch into simple sugars. Because most process energy in Brazil is already renewable, this does not really play a role.) Sugarcane ethanol 173
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Sugarcane ethanol Contributions to
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Table of contents Foreword 11 José
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Chapter 8 �e global impacts of US
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Foreword �e use of biofuels as a
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Executive summary Do biofuels help
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Executive summary 12. Projections o
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Chapter 1 Introduction to sugarcane
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Introduction to sugarcane ethanol A
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Introduction to sugarcane ethanol C
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Introduction to sugarcane ethanol F
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Introduction to sugarcane ethanol H
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Chapter 2 Production (million tons)
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Chapter 2 Table 2. Sugarcane produc
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Chapter 2 Harvested area (million h
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Chapter 2 million hectares 8 7 6 5
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Chapter 2 Table 5. Global significa
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Chapter 2 (FAOSTAT, 2008). �e lan
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Chapter 2 indicating that sugarcane
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Chapter 2 and vinasse produced duri
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Chapter 2 • • • • Harvested
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Chapter 2 2.2. AEZ assessment of la
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Chapter 2 The quantified descriptio
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Chapter 2 Table 8 summarizes by reg
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Chapter 2 Table 9. Suitability of u
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Chapter 2 Table 10. Suitability of
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Chapter 2 of bio-diversity and land
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Chapter 2 FAO, 1987. 1948-1985 Worl
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Chapter 2 Smeets, E., M. Junginger,
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Chapter 3 Considering that this deb
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Chapter 3 1,000 ha 9,000 8,000 7,00
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Chapter 3 Another source of data on
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Chapter 3 Figure 3. Different land
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Chapter 3 1-Pastureand crops expans
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Chapter 3 Given that the model is u
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Chapter 3 to the case studies; (d)
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Chapter 3 Mato Grosso do Sul in 200
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Chapter 3 the Pasture class increas
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Chapter 3 Table 5. Number of sugarc
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Chapter 3 of 12.6% from 2001 to 200
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Chapter 3 Table 6. South-Centre: ex
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Chapter 3 4.5. Options for approach
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Chapter 3 states that have lost pas
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Chapter 3 It is important to contex
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Chapter 4 Mitigation of GHG emissio
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Table 1. Basic data: sugarcane prod
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Mitigation of GHG emissions using s
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GHG emission (kg CO 2 eq/m 3 etOH)
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Table 7. Soil carbon content for di
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5. Conclusions Mitigation of GHG em
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Chapter 5 Oil reserves - Gasoline/d
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Chapter 5 in research and developme
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Chapter 5 Table 3. Summary of main
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Chapter 5 3. Environmental indicato
Page 118 and 119: Chapter 5 Table 4. Carbon stock in
Page 120 and 121: Chapter 5 3.2. Water Total carbon i
Page 122 and 123: Chapter 5 3.3. Soil and fertilizers
Page 124 and 125: Chapter 5 3.4. Management of diseas
Page 126 and 127: Chapter 5 Table 10. Sugarcane and v
Page 128 and 129: Chapter 5 in the implementation of
Page 130 and 131: Chapter 5 Table 11. Continued. Crit
Page 132 and 133: Chapter 5 Brazilian Government. Lei
Page 134 and 135: Chapter 5 São Paulo State Governme
Page 136 and 137: Chapter 6 2. Development of the eth
Page 138 and 139: Chapter 6 blends by car manufacture
Page 140 and 141: Chapter 6 Brazil have been roughly
Page 142 and 143: Chapter 6 Overall there are few di
Page 144 and 145: Chapter 6 3.2.1. The impact of exis
Page 146 and 147: Chapter 6 �e use of ethanol in he
Page 148 and 149: Chapter 6 cropping systems that pro
Page 150 and 151: Chapter 6 certainty, the supply of
Page 152 and 153: Chapter 6 De Vries, B.J.M., D.P. va
Page 155 and 156: Chapter 7 Biofuel conversion techno
Page 157 and 158: Biofuel conversion technologies �
Page 159 and 160: Biofuel conversion technologies In
Page 161 and 162: Biofuel conversion technologies the
Page 163 and 164: Biofuel conversion technologies Imp
Page 165 and 166: Biofuel conversion technologies Pro
Page 167: Investment costs (Euro/kWth input c
Page 171 and 172: Reduction in CO equivalent emission
Page 173 and 174: Biofuel conversion technologies �
Page 175 and 176: Biofuel conversion technologies pot
Page 177 and 178: Chapter 8 The global impacts of US
Page 179 and 180: The global impacts of US and EU bio
Page 187 and 188: Table 1. Change in output due to EU
Page 191 and 192: Forest cover Pasture cover USEU 201
Page 193: The global impacts of US and EU bio
Page 196 and 197: Chapter 9 also risks and serious tr
Page 198 and 199: Chapter 9 Box 2. Bioethanol stoves
Page 200 and 201: Chapter 9 �e highest impact on po
Page 202 and 203: Chapter 9 the increased generation
Page 204 and 205: Chapter 9 o�ers to support the MD
Page 206 and 207: Chapter 9 Price variation (%) 14 12
Page 208 and 209: Chapter 9 Dufey et al., 2007a). Leg
Page 210 and 211: Chapter 9 manufactured directly fro
Page 212 and 213: Chapter 9 in mechanical aid for the
Page 214 and 215: Chapter 9 Table 1. Import tariffs o
Page 216 and 217: Chapter 9 3.8. Improving efficiency
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Chapter 9 some minimum transport in
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Chapter 9 IEA, 2004. Biofuels for T
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Chapter 10 Why are current food pri
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Why are current food prices so high
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2.4 Long-term drivers of supply Why
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3.1. Effects on the supply side Why
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3.3 Policy responses to rising food
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3.4. Other effects • Why are curr
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- - - - Why are current food prices
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18 16 14 12 10 8 6 4 2 0 5. The fut
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• • • Why are current food pr
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6.1. Policy implications Why are cu
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Why are current food prices so high
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Authors Dr. Marcos Adami, senior re
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Keyword index A Africa 204, 205, 20
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M maize 20, 83, 104, 173, 184, 187,
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Sugarcane ethanol: Contributions to climate change - BAFF

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