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Transcript of Ethanol
Ethanol
Solar Energy
Photosynthesis
Biomass
Corn/Cane
Ethanol Bioethanol
Natural Vegetation(grass, foliage, timber)
Energy crops Ag and Urban Wastes
Crops
Avg. 0.3 - Max 6.7% of Incident Sunlight Converted to Biomass1
20 - 40%2,3,4
1 - Kheshgi et al. 2000 2 - Cook et al. 19913 - Lynd et al. 19914 - Wooley et al. 1999
33 - 54%1
Cellulosic Sources
• Bioethanol defined as being derived from cellulose/hemicellulose
• Types of energy crops:– Hybrid Poplars– Cottonwoods– Willows– Switchgrass
Poplars
Poplar Plantation
Poplar Cutting
Switchgrass Stand
Switchgrass
Cellulosic Biomass Composition
Cellulose 45%Hemicellulose 30%Lignin 15%Other 10%
Herbaceous Energy Crops
Cellulose 43%Hemicellulose 27%Lignin 17%Other 13%
Agricultural Residues
Municipal Solid Waste
Ash 15%Lignin 10%Hemicellulose 9%Other carbohydrates 9%Protein 3%Other 9%
Cellulose 45%
Cellulose 45%Hemicellulose 25%Lignin 22%Extractives 5%Ash 3%
Woody Crops
DOE approach
• Use of idle crop land (82 million acres)– 392 million acres are suitable for biomass
• best land is in the north central region
– Short-rotation woody crops expected annual yields of 5 or more dry tons
per acre could be grown on 225 million acres (2423 million tons) – Herbaceous energy crops with similar yields could be grown on 324
million acres (1427 million tons) – It would take 82 million acres (6 dry tons/acre) to produce 492 million tons
of dry biomass. This would yield to produce ~ 40 billion gallons of ethanol - enough to replace 22% of US gasoline consumption on an energy basis.
– If you used all 392 million acres ~ 190 million gallons, slightly more than enough ethanol to replace gasoline consumption.
U.S. Crop Suitability Map
Source: Oak Ridge National Laboratory
Source: ORNL County Level Study
Ethanol production using Switchgrass on Idled Cropland1
Idled
Cropland
(million acres)
Ethanol Produced
(million gallons)
2010 Demand Met using
Optimistic Biomass Yields
(%)
Region Medium2 Optimistic2 Region US
New England >1 22 24 >1 <1
Mid East 1 426 478 1 <1
Southeast 10 4,370 5,492 11 3
Great Lakes 6 2,443 2,896 9 9
Plains 20 7941 9,570 68 5
Southwest 8 3,426 4,175 17 2
Rocky
Mountain
0 0 0 0 0
Pacific 0 0 0 0 0
48 States 56 18,619 22,634 - 11
1 – Numbers may not add due to rounding
2 – Defined in Table 1.
Gasoline requirements per region (% of Total - 1.2 billion gallons)
27%
16%14%15% 8%
5%
3%
12%
5%
> 5 to 10%
> 10 to 20%
> 20%Do to rounding values may not equal 100%
Land Use in the Contiguous 48 States
Use Acreage(Million Acres)
Proportion ofTotal Area
(%)
Grassland Pasture& Range
ForestCroplandSpecial UseOther Use
589
55946019492
31
302410
5
Ne
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lan
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Mid
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So
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ea
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Gre
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ake
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Pla
ins
So
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we
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cky
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cific
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Sta
tes
0
50
100
150
200
250
300
350
Vol
ume
of E
than
ol (
Bill
ion
Gal
lons
)
US Region
2000 Ethanol Requirements
2010 Ethanol Requirements
Production Capacity
Ethanol Supply & Demand
1997 1998 1999 2000 2001 2002 2003 20040
500
1000
1500
2000
2500
3000
3500
Eth
an
ol A
mo
un
t (m
illio
n g
allo
ns)
Year
Supply
Demand
Projected Demand
Projected with no MTBE
Data from Urbanchik, 2000
Ethanol fuel properties in relation to fuel performance
Energy density
Heat of vaporization
Lower flame temperature
Relative volume ofcombustion products
Octane Number
0.65-0.69
2.3
0.976
1.07
1.15
Lower mpgLarger tank
More air to cylinderIncreased powerDecreased cooling needs
Higher efficiencyin optimized engine
Increases work from gas expansion
Allows increased compression ratio and hence higherPower and efficiency
PropertyEthanol/Gasoline
ValueImpact
From Lynd 1996;Bailey 1996
QuickTime™ and aPhoto - JPEG decompressor
are needed to see this picture.
Corn Milling Liquefaction Saccharification Fermentation
Distillation Dehydration
Centrifugation
Evaporation
Dry FeedMixing Drying Cooling
Corn
-Amylase Gluco-amylase Yeast
Fuel GradeEthanol
Denaturant
Distillers Dried Grains w/ soluble
Dry Milling Simplified Process
Net Corn Costs
Other Operating Costs
Annualized Capital Costs
Total Production Costs
0.45
0.34-0.45
0.26-0.49
1.05-1.40
0.37
0.31-0.47
0.20-0.44
0.90-1.33
$/gal
Dry Mill Wet Mill
Current Ethanol Costs
How much land for corn ethanol?
• 2.5 gallons of ethanol from a bushel of corn• US average corn yield per acre was 132 bushels
for the period from 1997 to 1999• Thus, a little under 3.9 million acres of corn is
needed to meet the current ethanol demand• 9.6 million acres would be needed to meet the
2004 ethanol demand
Issues
• The projected 2004 demand is essentially equivalent to the ethanol produced from cane sugar in Brazil (3.1 vs 3.4 billion gallons).
• Infrastructure development - mainly dry mills
• Co-products
• Energy Balance
Energy Requirements
• Units of Fossil Energy/Unit of Fuel Energy
– Gasoline 1.29 – Diesel 1.19
– Corn ethanol 0.99
• Sources: Sheehan [1998], Riley [1995], Shapouri [1995]
Reasons to use Bioethanol
• Energy security
• Petroleum prices rise
• CAFE Increase
• Serious about greenhouse gas emissions
Size ReductionDilute AcidPretreatment
Liquid Solid Separation
DetoxificationVia
Ion Exchange
Enzyme Production SSCF Fermentation
SeparationSolids ProcessingCogen
Biomass
Fuel GradeEthanol
Simplified Bioethanol Process
Energy Requirements
• Units of Fossil Energy/Unit of Fuel Energy
– Gasoline 1.29 – Diesel 1.19
– Corn ethanol 0.99– E95 (lignocell) 0.25
• Sources: Sheehan [1998], Riley [1995], Shapouri [1995]
Current Ethanol Costs
Net Feedstock Costs
Other Operating Costs
Annualized Capital Costs
Total Production Costs
0.45
0.34
0.26
1.05
0.37
0.31
0.22
0.90
$/gal
Dry Mill Wet Mill
0.37
0.25
0.54
1.16
Cellulosic
Effect of Biomass Cost on Ethanol Production Cost
$ 1.00/gal ethanol
$ 1.20/gal ethanol
E85 Costsvs
Gasoline Costs
Gasoline Cost
Volume Basis
Energy Basis
Dedicated E85 Vehicle
1.0 1.5 2.00.5
0.5
1.0
1.5
2.0
0.5
1.0
1.5
2.0
0.5
1.0
1.5
2.0
Ble
n de d
Fu e
ls C
ost s
($/
g al )
Gasoline Costs ($/gal)
$1.14
$0.94
$1.72
$1.42
$1.53
$1.26
Fuel Economics• Cellulosic ethanol currently costs too much• Gasoline $/gal $/liter
Refinery gate price: 0.80 0.21Transportation, storage, retailing: 0.40 0.11Taxes: 0.30 0.08Total (price at pump) 1.50 0.40
• EthanolProduction cost: 1.20 0.32Assume distribution $/gal as above 0.40 0.11Hold total tax revenue constant 0.20 0.05Total 1.80 0.48Total ($/volume gasoline equivalent) 2.70 0.71
Fuel/Vehicle Issues for Transition
• E10: current gasoline ICE are able to use up to E10• High level blends (up to E85): Flexible fueled ICE
– 2 million current vehicles in U.S.– Requires vehicle modifications– Dedicated vehicles slightly more efficient
• Start by all vehicles using E10 (50 billion liters for U.S., 10 X present production)
• Manufacture flexible fueled vehicles, gradually shifting to dedicated vehicles as ethanol production increases
For lignocellulosic ethanol to penetrate transportation fuel market:
• Technological advances & cost reductions• Infrastructure development• Higher petroleum prices• Stringent GHG emissions legislation• Subsidize production (via lower taxes)• Consumer demand for renewable fuels• Consumer acceptance of land use
0
20000
40000
60000
80000
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O2
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iv./v
ehic
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Operation
Fuel Cycle
Global Warming Potential for Alternative Fuel Vehicle Options
Ethanol OptionsLave 2000
Environmental Impact
• food vs. energy
• land use competition
• soil quality
• water quality
• chemical inputs
• biodiversity– monoculture
– suitability for wildlife habitat
– landscape effects
– stability
Could the U.S. produce sufficient ethanol from energy crops to fuel its
light-duty fleet? • To replace the 130 billion gallons (490 billion liters) of
gasoline, would require 300-500 million acres (approx. ¼ of land area lower 48 states)
• Investment in infrastructure (production facilities, distribution systems, retail stations) - $900 billion (over a decade)
Does this make sense?