Biofuels: Optimism and Concerns - Desert Research Institute
Biofuels: Optimism and Concerns - Desert Research Institute
Biofuels: Optimism and Concerns - Desert Research Institute
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<strong>Biofuels</strong>:<br />
<strong>Optimism</strong> <strong>and</strong> <strong>Concerns</strong><br />
2008 MIT/NESCAUM<br />
Symposium on Urban Transportation<br />
Endicott House<br />
Dedham, Massachusetts<br />
August 13, 2008<br />
S. Kent Hoekman, Ph.D.<br />
<strong>Desert</strong> <strong>Research</strong> <strong>Institute</strong><br />
Division of Atmospheric Sciences<br />
Kent.Hoekman@dri.edu
Outline<br />
1. Background on U.S. Energy Usage<br />
2. Policy <strong>and</strong> Regulatory Drivers for <strong>Biofuels</strong><br />
3. Feedstocks for <strong>Biofuels</strong><br />
4. Biomass Conversion Technologies<br />
5. Environmental Considerations<br />
6. Promoting Responsible Growth of <strong>Biofuels</strong><br />
7. Summary <strong>and</strong> Conclusions<br />
2
Historical Energy Use in the U.S.<br />
(Years 1775 – 2005)<br />
Current use of every primary energy source is greater now<br />
than at any previous time in U.S. history<br />
Source: http://www.eia.doe.gov/emeu/aer/pdf/aer.pdf<br />
3
Recent <strong>and</strong> Future U.S. Energy Production<br />
(Years 1980 – 2030)<br />
Source: EIA Annual Energy Outlook 2008<br />
4
Quads<br />
U.S. Renewable Energy<br />
(2006; with projections to 2030)<br />
In 2006, about 6.3% of total U.S. energy consumption came from<br />
renewables (including hydroelectric).<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
2006<br />
2030<br />
Source: DOE-EIA; Annual Energy Outlook 2008<br />
Biomass Energy<br />
Municipal Waste<br />
Residential Wood<br />
Wind<br />
Solar<br />
Geothermal<br />
Hydroelectric<br />
Other Trans Fuels<br />
Biodiesel<br />
Ethanol<br />
Current annual gasoline consumption is about 140 billion gallons –<br />
equivalent to 17.6 Quads<br />
5
Drivers for <strong>Biofuels</strong> in the U.S.<br />
• “America is addicted to oil.”<br />
– President G. W. Bush; January 2006<br />
• Federal Executive Actions:<br />
– Advanced Energy Initiative (AEI) (2006)<br />
– 20-in-10 Plan (2007)<br />
• Federal Legislative Actions:<br />
– Energy Policy Act of 2005<br />
– Energy Independence <strong>and</strong> Security Act<br />
of 2007<br />
• State Actions:<br />
– California Low Carbon Fuel St<strong>and</strong>ard<br />
– California AB-32 (GHG reduction)<br />
State of the Union<br />
Address (1/31/07)<br />
6
Benefits <strong>and</strong> Challenges of <strong>Biofuels</strong><br />
Improved Energy<br />
Security<br />
• Increased domestic<br />
supply<br />
• Widely distributed<br />
resources<br />
• Greater supply<br />
reliability<br />
• Petroleum reduction<br />
Economic<br />
Productivity<br />
• Price stability<br />
• Increased rural<br />
development<br />
• Reduced trade<br />
deficit<br />
• Improved global<br />
competitiveness<br />
Environmental<br />
And Other<br />
Impacts<br />
• GHG impacts<br />
• Carbon<br />
sequestration<br />
• L<strong>and</strong> <strong>and</strong> water use<br />
• Wildlife habitat<br />
• Biodiversity<br />
• Food resources<br />
7
Terminology for Liquid Transportation Fuels<br />
(Common terms, but not universally accepted)<br />
1. Conventional Fuels: produced from petroleum<br />
2. Alternative Fuels: produced from non-petroleum sources,<br />
including other fossil sources (coal, natural gas)<br />
3. Renewable Fuels: produced from modern biological precursors<br />
(plants <strong>and</strong> animals)<br />
4. <strong>Biofuels</strong>: synonymous with “Renewable Fuels”<br />
5. 2 nd Generation <strong>Biofuels</strong>: <strong>Biofuels</strong> produced from non-food<br />
feedstocks – especially lignocellulose<br />
6. Biodiesel: methyl esters produced from fats <strong>and</strong> oils<br />
7. Renewable Diesel: non-fossil hydrocarbon fuel produced via<br />
hydroprocessing of fats <strong>and</strong> oils<br />
8. Cellulosic Fuels: produced via biochemical or thermochemical<br />
conversion of lignocellulosic materials<br />
9. Clean Fuels: ??<br />
8
Rapid Growth of <strong>Biofuels</strong> in the U.S.<br />
• Currently dominated by corn-based<br />
ethanol<br />
– 6.4 billion gallons in 2007<br />
– Supplies about 4% of U.S. gasoline<br />
dem<strong>and</strong><br />
– Requires about 15% of U.S. corn crop<br />
• Biodiesel is growing, but still small<br />
– 0.45 billion gallons in 2007<br />
– Supplies ~1% of U.S. diesel dem<strong>and</strong><br />
– Main feedstocks:<br />
• U.S. – soy oil <strong>and</strong> waste oils<br />
• Europe – rapeseed oil<br />
9
Billion Gallons/Year<br />
2005<br />
Energy Act<br />
2007 Energy Act<br />
U.S. Renewable Fuels Production<br />
<strong>and</strong> Volume Requirements, bg/y<br />
36<br />
32<br />
Production Volumes<br />
Energy Act Requirements<br />
28<br />
24<br />
Cellulosic<br />
Ethanol<br />
20<br />
16<br />
Other Renewables<br />
Biodiesel<br />
12<br />
8<br />
4<br />
Ethanol<br />
Biodiesel<br />
Corn Ethanol<br />
Corn Ethanol<br />
0<br />
Year<br />
36 bg/y represents about 25% of current gasoline volume<br />
10
Biomass Resource Base in U.S.<br />
Primary<br />
Secondary<br />
Tertiary<br />
Forest Resources<br />
• Logging residues<br />
• Forest fuel treatment<br />
• Fuel wood<br />
• Mill residues<br />
• Pulping liquors<br />
• Wood processing residues<br />
• Construction debris<br />
• Demolition debris<br />
• Urban tree trimmings<br />
• Packaging waste<br />
Agricultural Resources<br />
• Crop residues<br />
• Grain<br />
• Perennial grasses<br />
• Woody crops<br />
• Animal manures<br />
• Food/feed processing<br />
residues<br />
• Municipal solid waste<br />
(MSW)<br />
• L<strong>and</strong>fill gases<br />
11
U.S. Forest Biomass Resources,<br />
million dry tons/year (mdt/y)<br />
Source: DOE/USDA, The Technical Feasibility of a Billion-Ton Annual Supply<br />
(April 2005)<br />
12
Potential U.S. Agricultural Biomass<br />
Resources (mdt/y)<br />
Source: DOE/USDA, The Technical Feasibility of a Billion-Ton Annual Supply (April 2005)<br />
13
Major <strong>Biofuels</strong> Production Pathways<br />
Feedstock Process Main Fuel Products<br />
Starch, Sugar<br />
Corn, sugar cane,<br />
sorghum, etc.<br />
Lignocellulose<br />
Wood waste<br />
Grasses<br />
Trees<br />
Ag. waste<br />
Triglycerides<br />
Vegetable oils<br />
Animal fats<br />
Algal lipids<br />
Hydrolysis/<br />
Fermentation<br />
Biochemical<br />
Pretreatment<br />
Enzymatic Hydrolysis<br />
Fermentation<br />
Thermochemical<br />
gasification<br />
pyrolysis<br />
Transesterification<br />
Hydroprocessing<br />
Ethanol<br />
Ethanol<br />
Alcohols,<br />
Hydrocarbons<br />
Fatty Acid Methyl<br />
Esters (Biodiesel)<br />
Hydrocarbons<br />
(Renewable Diesel)<br />
14
DOE’s Integrated Biorefinery Concept<br />
Source: NREL (2006)<br />
15
Environmental <strong>Concerns</strong> with <strong>Biofuels</strong><br />
• Water quantity <strong>and</strong> quality<br />
• Runoff of nutrients <strong>and</strong><br />
agricultural chemicals<br />
• Long-term impacts of crop<br />
residue removal<br />
• Disruption of habitat<br />
• Effects on biodiversity<br />
• Sustainability of agricultural<br />
<strong>and</strong> forestry practices<br />
For ecologic dimensions of biofuels, see links at:<br />
www.esa.org/science_resources/biofuelsResources.php<br />
16
Life-Cycle Impacts of <strong>Biofuels</strong><br />
Many different life-cycle assessments<br />
(LCA) have been conducted by many<br />
different researchers.<br />
Very controversial area. Results<br />
depend upon assumptions about:<br />
‣ Allocations of energy <strong>and</strong> GHGs to coproducts<br />
‣ Agricultural practices <strong>and</strong> resulting GHG<br />
emission rates (especially N 2 O)<br />
‣ Type <strong>and</strong> extent of fossil energy used in<br />
life-cycle<br />
‣ L<strong>and</strong> use changes: CO 2 debt created<br />
by l<strong>and</strong> clearing <strong>and</strong> new cultivation<br />
17
Many LCA Studies Conducted for Ethanol<br />
• Recent model developed by<br />
Ferrell et al. to harmonize<br />
assumptions used in many LCA<br />
studies.<br />
• In general, results show:<br />
- Small energy <strong>and</strong> GHG benefits<br />
from corn-derived ethanol<br />
- Large benefits from cellulosic<br />
ethanol<br />
• Limitation: study considers only<br />
direct effects, not indirect effects<br />
due to l<strong>and</strong> use changes<br />
Source: Farrell et al, Science, 311, 506-508 (2006)<br />
18
General Observations Regarding LCA of <strong>Biofuels</strong><br />
• Importance of indirect effects is now recognized<br />
– No consensus on how to quantify these effects<br />
– No consensus on how (or if) to incorporate into policy<br />
• LCA results are highly scenario specific – very difficult to<br />
generalize for a particular biofuel<br />
• 2 nd generation biofuels are clearly preferred over 1 st<br />
generation biofuels<br />
• Recent publications of interest:<br />
- R.Hammerschlag, Environ. Sci. Technol. 40, 1744-1750 (2006)<br />
- E.A.Farrell et al., Science, 311, 506-508 (2006)<br />
- J.P.W.Scharlemann <strong>and</strong> W.F.Laurance, Science 319, 43-44 (2008)<br />
- J.Fergione et al., Science 319, 1235-1238 (2008)<br />
- T.Searchinger et al. Science 319, 1238-1240 (2008)<br />
19
Promoting Responsible Growth of <strong>Biofuels</strong> (1 of 4)<br />
1. Avoid “One-Size-Fits-All” Approach<br />
– Maximize usage of local/regional biomass resources<br />
– Minimize transportation of feedstocks<br />
– Exp<strong>and</strong> diversity of feedstocks, processes, <strong>and</strong> products<br />
– There is no single best technology<br />
• Match technology with available feedstock<br />
• Integrate technologies – biorefinery concept<br />
20
Promoting Responsible Growth of <strong>Biofuels</strong> (2 of 4)<br />
2. Emphasize Sustainability of <strong>Biofuels</strong><br />
– Life-cycle assessments (LCA) are very important<br />
• Must be improved/exp<strong>and</strong>ed<br />
• Consider both direct <strong>and</strong> indirect effects<br />
• Consider energy, GHG, environ., <strong>and</strong> ecological impacts<br />
• Develop common metrics that accurately reflect true impacts<br />
– Minimize tradeoff between food <strong>and</strong> fuel. Consider 1 st<br />
generation biofuels as temporary transition to 2 nd generation<br />
– Economic sustainability is also important<br />
Source: CEC Report 600-2007-004-Rev., August 2007<br />
21
Promoting Responsible Growth of <strong>Biofuels</strong> (3 of 4)<br />
3. Promote Consumer Acceptance<br />
– Dem<strong>and</strong> high fuel quality<br />
• At refinery gate, <strong>and</strong> in marketplace<br />
• Develop <strong>and</strong> enforce product specifications<br />
– Maximize use of existing infrastructure<br />
• Refining, blending, storage, distribution, marketing<br />
• Minimize changes for consumer<br />
– Ensure acceptable cost, availability, convenience, <strong>and</strong><br />
performance of products<br />
22
Promoting Responsible Growth of <strong>Biofuels</strong> (4 of 4)<br />
4. Integrate Biomass-to-<strong>Biofuels</strong> Supply Chain<br />
– All steps in supply chain are important<br />
– Entire chain must be economically sustainable<br />
Source: DOE Biomass Multi-Year Program Plan (2007)<br />
23
Summary <strong>and</strong> Conclusions (1 of 2)<br />
1. 2 nd Generation biofuels can<br />
play an important role in<br />
stabilizing GHGs <strong>and</strong><br />
reducing petroleum<br />
dependency.<br />
2. <strong>Biofuels</strong> industry is<br />
currently undergoing rapid<br />
transformation <strong>and</strong> growth.<br />
• Many biochemical <strong>and</strong><br />
thermochemical<br />
technologies are being<br />
explored<br />
• No single “best approach”<br />
is likely to emerge<br />
Source: http://celebrating200years.noaa.gov<br />
24
Summary <strong>and</strong> Conclusions (2 of 2)<br />
3. U.S. has abundant natural resources to support<br />
production of 2nd generation biofuels sufficient to<br />
displace 30-40% of conventional fuels.<br />
4. Sustainable implementation of biofuels requires:<br />
• Careful attention to adverse impacts on natural resources,<br />
environment, <strong>and</strong> ecology<br />
• Development of common metrics <strong>and</strong> methods for assessing<br />
life-cycle impacts<br />
5. For widespread consumer acceptance, biofuels must<br />
be conveniently available, affordable, <strong>and</strong> compatible<br />
with conventional fuel/vehicle systems.<br />
25
Thank You!