WHY CELLULOSIC ETHANOL IS NEARER
THAN YOU MAY THINK
Bruce E. Dale
Dept. of Chemical Engineering & Materials Science
Michigan State University
www.everythingbiomass.org
Presented at:
2007 NACAA Conference
Grand Rapids, Michigan
July 16, 2007
1978 – 2007 CRUDE OIL PRICES
IT PAYS TO BE PATIENT
President Bush promotes
cellulosic ethanol
My career begins
Linked Sustainability Challenges of the
Coming Decades
• Diversify transportation fuels & end strategic
role of petroleum in the world
• Provide food for growing & wealthier population
(which will consume more meat)
• Control greenhouse gases & limit other human
emissions (for example, nitrogen & phosphorus
discharge to ground & surface waters)
• Provide economic opportunities for rural people
• These challenges & opportunities intersect at
biofuels, particularly cellulosic biofuels
• Abundant opportunities for creative design &
system level thinking
Some Basic Energy Facts
1. We do not need “energy”…we need services that
energy provides
2. The services we need from energy are (current
sources or carriers of these energy services)
•
•
•
Heat (natural gas, coal)
Light (coal, natural gas, hydro & nuclear)
Mobility (petroleum—97%, rest is ethanol)
3. Energy has fundamentally different qualities:
carriers are not all interchangeable “All BTU are
not created equal”
4. Industrial society literally stops without liquid fuels
5. Liquid fuels: not “energy” are required for mobility
for the next few decades at least!
The Problem:
Our Society STOPS
Without Liquid Fuels!
All Energy Carriers do Not Have Equal
Strategic Importance Either
1. Coal– U.S. & China have huge domestic reserves
2. Natural gas—imports significant, mostly from
Canada and Mexico
3. Petroleum– more than 60% imported (U.S.) and
rising
•
•
•
•
“We (U.S.) are addicted to oil” President Bush
Oil revenues sustain oppressive & aggressive regimes
Oil used as a political weapon
Oil revenues finance international terrorism
4. Petroleum dependence undermines
1. climate security (a chief source of greenhouse gases)
2. economic security (no fuels = no movement of goods =
no trade = no prosperity)
3. international security & world stability
Options for Dealing with Petroleum Issue
1. Decrease demand
•
More petroleum efficient vehicles
– Better mileage (start measuring vehicle efficiency by
“petroleum per mile” or “miles per gallon gasoline”
– Electrical/hybrid vehicles
•
Fewer miles traveled (better planning)
2. Increase supply
•
•
•
•
•
Athabasca oil sands (Canada)
Oil shale (U.S.)
Super heavy oil (Venezuela)
Coal to liquid fuels (U.S., South Africa, China)
Biofuels
– Biodiesel
– Ethanol (from sugar, from corn, from cellulosics)
Why Biofuels?
• Biofuels, including cellulosic ethanol, are one
of a small handful of petroleum alternatives
that can provide:
– (inter) national security advantages
– large greenhouse gas reductions
– economic advantages (lower cost fuels than
petroleum fuels)
• This presentation emphasizes cellulosic
ethanol
– From agricultural and forestry residues
– From “energy crops”
Ethanol Production Flowchart
Corn Process
Sugar
Corn
Kernels
Starch
Conversion
(Cook or
Enzymatic
Hydrolysis)
Fermentation
Distillation
Co-Product
Recovery
Animal Feed
Chemicals
Drying
Ethanol
Ethanol Production Flowchart
Corn Process
Sugar Cane Process
Sugar
Cane
Corn
Kernels
Starch
Conversion
(Cook or
Enzymatic
Hydrolysis)
Sugar
Fermentation
Distillation
Co-Product
Recovery
Animal Feed
Chemicals
Drying
Ethanol
Ethanol Production Flowchart
Cellulose Process
Corn Process
Sugar Cane Process
Sugar
Cane
Corn
Kernels
Cellulose
Cellulose
Pretreatment
Sugar
Starch
Conversion
(Cook or
Enzymatic
Hydrolysis)
Cellulose
Conversion
Hydrolysis
• Crop residues: corn stover, rice
straw, wheat straw, etc.
• Forestry residues/slash
• Energy crops: switchgrass, poplar,
Miscanthus, many others
• Municipal & construction wastes, etc
Fermentation
Distillation
Co-Product
Recovery
Animal Feed
Chemicals
Drying
Ethanol
Ethanol Production Flowchart
Cellulose Process
Corn Process
Sugar Cane Process
Sugar
Cane
Corn
Kernels
Cellulose
Cellulose
Pretreatment
Sugar
Starch
Conversion
(Cook or
Enzymatic
Hydrolysis)
Fermentation
Distillation
Drying
Co-Product
Recovery
Animal Feed
Chemicals
Cellulose
Conversion
Hydrolysis
•
•
•
•
•
•
Corn Stover
Switchgrass
MSW
Forest Residues
Ag Residues
Wood Chips
Thermochemical
Conversion
• Heat and Power
• Fuels and Chemicals
Ethanol
Major Cost Elements:
Petroleum Fuels & Biofuels
For all commodity products (fuels, bulk
chemicals, semiconductor chips, potato
chips, etc.) two things determine the
final selling price:
1. Cost of raw material (the feedstock)
2. Cost of processing the feedstock to the
desired product(s)
For gasoline, diesel, etc. the cost to make
them depends on petroleum cost (70%)
and processing cost (30%)
Adapted from Lynd & Wyman
160
Energy content
Cost of biomass, $/ton
140
120
100
80
60
Forages & hay crops-typical prices
Our margin for processing: here to here
and beyond
40
20
0
0
10
20
30
40
50
60
Cost of oil, $/barrel
Plant material is much, much cheaper than oil on both energy & mass basis
Impact of Processing Improvements: Oil’s
Past & Future
• Historically, petrochemical
processing costs exceeded
feedstock costs
Relative Cost
• Petroleum processing
efficiencies have increased
and costs have decreased
dramatically but reaching
point of diminishing returns
• Petroleum raw materials have
long-term issues
Early Years
Today's Mature
Processes
Oil
– Costs will continue to increase as
supplies tighten
– High price variability
– Impacts national security
– Climate security concerns
– Not renewable
Future
Processing
•
From J. Stoppert, 2005
Not a pretty picture for our
petroleum dependent society
Brazil Has Been Reducing Sugar Ethanol Costs for 30 Years
Cellulosic Ethanol Costs Have Declined and Will Decrease More!
Ethanol-Brazil
Gasoline-Rotterdam
Impact of Processing Improvements: The
Future of Cellulosic Biomass Conversion
•
•
Relative Cost
•
?
•
•
Processing is dominant cost
of cellulosic biofuels today
Cellulosic biomass costs
should be stable or decrease
Processing costs dominated
by pretreatment, enzymes &
fermentation
Biomass processing costs
must (& will) decrease
Two ways to do this:
1. “Learning by doing” in large
scale plants
2. Applied (cost focused) research
•
Today
Future
Adapted from J. Stoppert, 2005
Much more attractive future
–
–
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Domestically produced fuels
Environmental improvements
Rural/regional economic
development
Testing AFEX pretreatment technology
Key Processing Cost Elements
33%
Biomass Feedstock
Feed Handling
Capital Recovery
Charge
5%
Pretreatment / Conditioning
Grid Electricity
SSCF
Raw Materials
Cellulase
12%
9%
Distillation and Solids
Recovery
Total Plant
Electricity
(after ~10x cost reduction)
10%
Wastewater Treatment
Process Elect.
Fixed Costs
18%
4%
Net 4%
Boiler/Turbogenerator
Utilities
4%
Storage
(0.20)
Biomass Refining CAFI
(0.10)
1%
-
0.10
0.20
0.30
0.40
Central Role and Pervasive Impact of
Pretreatment for Biological Processing
Enzyme
production
Biomass
production
Harvesting,
storage,
size reduction
Pretreatment
Enzymatic
hydrolysis
Sugar
fermentation
Hydrolyzate
conditioning
Hydrolyzate
fermentation
Ethanol
recovery
Residue
utilization
Biomass Refining CAFI
Waste
treatment
Cellulosic Biomass to Ethanol
Cellulosic
Biomass
Production
Biomass Conversion
Research Lab at Michigan
State Works Here Using
AFEX Process
DOE 2005
How does AFEX work?
Recycle
Ammonia
Biomass
Ammonia
Recovery
Gaseous
Ammonia
Heat
Reactor
Explosion
Expansion
Treated
Biomass
 Biomass heated (~100 C) with concentrated ammonia
 Rapid pressure release ends treatment
 99% of ammonia is recovered & reused, remainder
serves as N source downstream for fermentation
 AFEX covered by multiple U. S. and international patents
 Sugars not degraded, fermentation inhibitors NOT
produced
Before and After AFEX
Pretreatment Economic Analysis by NREL
$/gal EtOH
Proof Year: 4th Year of Operation
1.75
AFEX:
$1.41/gal
1.50
1.25
1.00
0.75
MESP
Cash
Cost
0.50
Plant
Level
0.25
0.00
Dilute Acid
Net Stover
Other Variable
Hot Water
AFEX
Fixed w/o Depreciation
ARP
Depreciation
Lime
Income Tax
Corn Dry Mill
Return on Capital
Results of AFEX Economic Analysis*
• Reduce ammonia loadings
• Reduce required ammonia recycle
concentrations (manage system water)
• Reduce capital cost of AFEX
• *Analysis performed by Dr. Tim Eggeman of NREL
Improvements in AFEX Give
Improved Ethanol MESP
Stover Feedstock Cost
Processing Cost
$1.60
$1.40
Original estimate2,205 dry ton/day scale
Reduced ammonia loading & concentration
MESP ($/gal)
$1.20
$1.00
Plus new ammonia recovery
approach
$0.80
$0.60
$0.40
$0.20
$0.00
NREL-2004 SSF-COMP- SSF-NEWUPD
UPD
CBP-NEWUPD
Simulation
Mature
Final Result will be Low Cost
Ethanol from Cellulose
Stover Feedstock Cost
$1.60
Processing Cost
2,205 dry ton/day scale
MESP ($/gal)
$1.40
D
~$0.62
$1.20
$1.00
$0.80
$0.60
$0.40
$0.20
$0.00
NREL-2004
SSF-COMPUPD
SSF-NEWUPD
Simulation
CBP-NEWUPD
Mature
Ethanol from Cellulosics: Look for Fast Growth!
courtesy Dr. Steve Long UICU
What Happens Because of Inexpensive Ethanol?
• Petroleum dominance declines
– Reduce petroleum’s influence on prosperity & politics
– Less chance for international conflict
– Greater economic growth opportunities for poor nations
• Environmental improvements possible
– Reduced greenhouse gases
– Reduced nitrogen & phosphorus-related pollution
– Improved soil fertility
• Rural economic development possible
– Local cellulosic biomass processing
– Greater wealth accumulation in rural areas
– Less migration to cities to find economic opportunity
• Less expensive food (animal feed) possible
– Improved animal feeds: protein & calories
– Less expensive, more abundant human food
Will People Go Hungry Because of Biofuels?
• Three major U.S. crops alone (corn, soy, wheat) produce
1300 trillion kcal & 51 trillion grams protein/yr
• Could meet U.S. human demand for protein & calories
with 25 million acres of corn (~5% of our cropland)
• Most U. S. agricultural production (inc. exports) is fed to
animals-- i.e., we are meeting their protein/calorie needs
from our land resources. Their needs are:
– 1040 trillion kcal/yr ( 5 times human demand)
– 56.6 trillion gm protein/yr (10 times human demand)
• Thus we can address perceived “food vs. fuel” conflict by
providing animal feeds more efficiently, on less land
• Dairy & beef cattle consume more than 70% of all
calories and protein fed to livestock
• As nations grow richer, they want more protein,
especially more meat….
U.S. Livestock Consumption of Calories & Protein
HERD SIZE
TOTAL
PROTEIN
TOTAL ENERGY
(THOUSANDS)
(MILLION KG/YR)
(TRILLION CAL/YR)
Dairy
15,350
10,400
184.8
Beef
72,645
25,100
525.3
Hogs
60,234
6,900
136.2
Sheep
10,006
461
10.6
Egg production
446,900
2,470
4.3
Broilers produced
8,542,000
9,540
150.3
Turkeys produced
269,500
1,760
28.6
Total consumed by
U.S. livestock
56,630
1,040.00
Human requirements
5,114
205
ANIMAL CLASS
Coproducing Animal Feeds and Biofuels
• Must supply animals (fish, poultry, swine, cattle) with:
– Calories (food energy), and
– Protein
• Can grow grasses with high protein content & recover
the protein with well-known (since 1945) technology
• Grasses/crop residues/woody materials also have lots
of calories as sugars “locked up” in plant cell walls.
• Pretreatment processes required to “unlock” these
sugars to make cellulosic ethanol could also unlock
these sugars for ruminant animal feeding
• Cellulose-based biorefineries could also be in the
animal feed business: this is a really important “food
vs. fuel” opportunity
Ruminant Animals & Biorefineries:
Improve Cellulose Conversion for Biorefinery
= Improve Cellulose Digestibility for Cows
Mobile Cellulose Biorefinery
(a.k.a. Cow)
Stationary Cellulose Biorefinery
=
Ruminant Bioreactor:
SSCF Bioreactor:
Biomass Input ~ 26 Lb/Day*
Biomass Input ~ 5,000 Dry Ton/Day
= 10 M Dry Lb/Day
Capacity ~ 45 M Gal Fermentor
Capacity ~ 40 Gal Fermentor
Cow is 3x more efficient than industrial bioreactor
*Rasby, Rick. “Estimating Daily Forage Intake of Cows”. University of Nebraska-Lincoln
Institute of Agriculture and Natural Resources, http://beef.unl.edu/stories/200608210.shtml,
10/02/06.
What Might the Future Look Like?
•
Land available (million acres)
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Cropland (430): corn, wheat, soy, sorghum, alfalfa, hay, CRP
Permanent pasture (570)- half suitable for mechanical harvest
Most of these acres suitable for perennial grasses
Does NOT include forests
Assume we can develop a pretreated perennial grass
yielding 10 tons/acre/yr with 10% protein, 75% cellulose +
hemicellulose (90% digestible), 15% lignin and ash
Supply ruminants 710 trillion cal/yr & 36 trillion grams
protein/yr using ~40 million acres of productive grasses
Leaves available >600 million acres for other feeds,
human foods and biofuel production
I simply do not agree that land for food is a limiting
resource for biofuel production—animal feed is the issue
Thinking Ahead: Farmers & Biofuels
“More
than a century of bitter experience
has taught farmers that when they
simply sell a raw crop, they fall ever
further behind.”
David Morris “The American Prospect” April 2006
Capturing Local Benefits from Biofuels
•
Some issues for farmers/local interests
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–
•
If farmers merely supply biomass, they will not benefit much from
the biofuels revolution
Investment required for cellulosic ethanol biorefinery is huge ~
$250 million and up—difficult for farmers to participate
Some issues for biofuel firms/larger society
–
–
–
•
Supply chain issues are enormous—need 5,000 ton/day from
~1,000 farmers: chemicals/fuels industries have zero experience
with such large agricultural systems
Cellulosic biomass is bulky, difficult to transport
Need to resolve “food vs. fuel” problem: actually “animal feed and
fuel opportunity”
Is there a common solution?
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–
–
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Regional Biomass Processing Center– concept worthy of study
Pretreat biomass for biorefinery & ruminant (cattle) feeding
Much lower capital requirements—accessible to rural interests
Develop additional products over time—animal feed protein,
enzymes, nutraceuticals, biobased composites, etc
Ethanol: Some Myths and Realities
•
•
•
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Myth: Ethanol has a negative “net energy”
Reality: Gasoline’s “net energy” is worse than ethanol’s
and anyway this metric is irrelevant
Myth: Ethanol will drive up food prices
Reality: Complicated: no easy sound bites for fuels
derived from oilseeds or grains. Cellulosic ethanol will
reduce food prices
Myth: Ethanol is bad for the environment
Reality: Compared with what? Corn ethanol is
superior to gasoline now for most metrics. Cellulosic
ethanol will be even better
Myth: Ethanol will always cost more than gasoline
Reality: Ethanol from corn costs ~$1.20/gal; ethanol
from cellulosics, when mature, will cost $0.60/gal
1978 – 2007 CRUDE OIL PRICES
IT PAYS TO BE PATIENT
President Bush promotes
cellulosic ethanol
My career begins
“Absolutely!”
Questions ??