CELLULOSIC ETHANOL _ SUSTAINABILITY by RG

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									CELLULOSIC ETHANOL & SUSTAINABILITY: THERE IS NO “FOOD VS. FUEL” CONFLICT
Bruce E. Dale Dept. of Chemical Engineering & Materials Science Michigan State University www.everythingbiomass.org Presented at: American Chemical Society Meeting Chicago, Illinois March 26, 2007

Some Expressions of Food vs. Fuel Concerns*
• ―Anything but a marginal contribution from biofuel would pose a serious threat to both food security and the natural resource base‖ • ―Koonin’s analysis does not address the environmental costs (specifically land degradation) of producing biofuels‖ • ―…the ecological devastation wrought by industrial biofuel production must be severe.‖ • ―Ethanol from corn is neither scalable nor sustainable.‖ • ―…the production of relatively inefficient transportation fuels at the expense of soil resources and in the face of increasing global populations is irresponsible.‖ • *All from Science. Vol. 312. 23 June 2006. Letters.

Some Key Facts are Ignored or Missed
1. Corn ethanol is self limiting. Other uses will limit corn utilization for fuels 2. Cellulosic ethanol will not affect food supplies, if anything it will increase them
• • • • Billions of tons of cellulosic residues (& lots of underutilized land also) Energy crops can be grown on marginal lands Energy crop yields will increase—further reducing competition for land for food Food (actually animal feed) can & will be coproduced with energy crops

Sugarcane Bagasse

Courtesy of Dr. Charles Wyman, U. Calif. Riverside

Rice Hulls Pile

Courtesy of Dr. Charles Wyman, U. Calif. Riverside

Significance of the 1.3 Billion Ton Biomass Scenario

Based on ORNL & USDA Resource Assessment Study by Perlach et.al. (April 2005) http://www.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf

Courtesy M. Pacheco, NREL

International Crop Residue Supply
Material (billion kg)
Corn stover Africa Asia Europe North America Central America Oceania South America Sub Total

0.0

33.9

28.6

134

0.0

0.2

7.2

203.6

Barley straw
Oat straw Rice straw

0.0
0.0 20.9

2.0
0.3 668

44.2
6.8 3.9

9.9
2.8 10.9

0.2
0.0 2.8

1.9
0.5 1.7

0.3
0.2 23.5

58.5
10.6 731.3

Wheat straw Sorghum straw
Bagasse Subtotal

5.3 0.0
11.7 38.0

145 0.0
74.9 924

133 0.4
0.01 216

50.1 6.9
4.6 219

2.8 1.2
19.2 26.1

8.6 0.3
6.5 19.7

9.8 1.5
63.8 106.3

354.4 10.3
180.7 1549.4

Why are Yields Important?
• Increased biomass yields:
– boost farmer returns per acre – reduce raw material and capital costs of biorefinery – reduce total land required to meet human needs, thus more parks, preserves, wilderness

• But temperate/tropical yields of grasses/legumes vary between 2-50 tons/acre/year—huge range • Very little work done to breed, cultivate most grasses for total biomass yields-- great potential for increase • At 2% plant solar energy conversion efficiency (vs. 12% theory), 3% of our land covered with biomass equals total U. S. petroleum energy used

Yields & Photosynthetic Efficiencies of Some Crops
Location Minnesota N. Zealand Australia Colombia Hawaii Java Puerto Rico Crop Corn Grass Rice Pangola Cane Cane Napier Yield,tpay 11.0 13 16 22.4 33.4 38.8 47.3 SEC % 0.79 1.02 1.04 1.50 2.24 2.59 2.78

From Tab. 23, Klass vol. 12. Kirk Othmer Enc. Chem. Technol.

Miscanthus late summer- annual shoots (20 tons/acre/yr)

courtesy Dr. Steve Long

Will People Go Hungry Because of Biofuels?
• Macronutrients: 2000 cal & 50 gm protein/person/day • Total U.S. human demand: 205 trillion cal & 5.1 trillion grams protein/yr • 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 • 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)

• Can address perceived ―food vs. fuel‖ conflict by providing animal feeds more efficiently, on less land • Ruminants (dairy & beef cattle) consume ~70% of all calories and protein fed to livestock

U.S. Livestock Consumption of Calories & Protein
HERD SIZE
ANIMAL CLASS Dairy
(THOUSANDS)

TOTAL PROTEIN
(MILLION KG/YR)

TOTAL ENERGY
(TRILLION CAL/YR)

15,350 72,645 60,234

10,400 25,100 6,900

184.8 525.3 136.2

Beef Hogs Sheep Egg production Broilers produced Turkeys produced
Total consumed by U.S. livestock

10,006
446,900

461
2,470

10.6
4.3

8,542,000 269,500

9,540 1,760

150.3 28.6

56,630

1,040.00

Human requirements

5,114

205

Two Technical Prerequisites for Large Scale Biofuels
1. Effective, economical pretreatment to increase accessibility/digestibility of cellulose and hemicellulose (60-80% of forages, etc) 2. Complete utilization of all biomass components: carbohydrates, lignin, protein, lipids, minerals, pigments, pectin, organic acids, etc.

R u m i n a n t An i m a l s & B i o r e f i n e r i e s
Mobile Cellulose Biorefinery (a.k.a. Cow) Stationary Cellulose Biorefinery

=
Ruminant Bioreactor:
Biomass Input ~ 26 Lb/Day*
Capacity ~ 40 Gal Fermentor
*Rasby, Rick. ―Estimating Daily Forage Intake of Cow s‖. University of Nebraska-Lincoln Institute of Agriculture and Natural Resources, http://beef.unl.edu/stories/200608210.shtml, 10/02/06.

SSCF Bioreactor:
Biomass Input ~ 5,000 Dry Ton/Day = 10 M Dry Lb/Day
Capacity ~ 45 M Gal Fermentor

Cow is 3x more efficient than bioreactor

What Might the Future Look Like?
•
– – – –

Land available (million acres)
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

• •
•

•
– –

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 We can (and will) integrate animal feed and biofuel production to their mutual advantage
Increasing food supplies Reducing biofuel costs

Biomass Processing to Fuels: Estimated Costs at Process Maturity*
Scenario EtOH/ Rankine EtOH/ GTCC EtOH/FT/ GTCC
EtOH/Protein/ Rankine

$/gal ethanol $0.60 $0.63 $0.72
$0.49

$/gal gas equivalent $0.91 $0.95 $1.09
$0.74

$/gal diesel equiv. na na $1.02
na

*From “Growing Energy:The Role of Biofuels in America’s Energy Future” 2004 NRDC

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
If farmers merely supply biomass, they will not benefit much from the biofuels revolution Environmental benefits depend largely on local factors—requires local control & optimization 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 Supply chains established for grains, not so much for grasses Cellulosic biomass is bulky, difficult to transport Need to resolve ―food vs. fuel‖: actually ―feed & fuel opportunity‖

•
– – – –

Is there a common solution?
Regional Biomass Processing Center– concept worthy of further study and development Pretreat biomass for biorefinery & ruminant animal feeding Much lower capital requirements—accessible to rural interests Perhaps some high value uses: materials, nutraceuticals, enzymes, etc.

Some Key Facts are Ignored or Missed
1. Corn ethanol is self limiting. Other uses will limit corn utilization for fuels 2. Cellulosic ethanol will not affect food supplies, if anything it will increase them
• • • • Billions of tons of cellulosic residues (& lots of underutilized land also) Energy crops can be grown on marginal lands Energy crop yields will increase—further reducing competition for land for food Food (actually animal feed) can & will be coproduced with biofuels to their mutual benefit

Questions ??

―Absolutely!‖

Hysteria over Corn Ethanol?*
• ―No crop grown in the United States consumes and pollutes more water than corn‖ • ―Needed for the production of one gallon of ethanol are 1,700 gallons of water, mostly in the form of irrigation.‖ • ―and creates 12 gallons of a sewage-like effluent‖ • ―It takes more energy in the form of fossil fuels to make corn-based ethanol than we get from it‖ • ―USDA (a wholly owned subsidiary of agribusiness)‖
• *Fisherman Magazine…April 2007

Let’s Be Smarter this Time
“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

Cellulosic Biomass Production

Biomass Conversion Research Lab at Michigan State Works Here Using AFEX Process

DOE 2005

How does AFEX work?
Recycle Ammonia

Ammonia Recovery

Gaseous Ammonia

Biomass

Heat

Reactor

Expansion Explosion

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

 Minimize sugar degradation, relatively mild conditions

―Absolutely!‖

Composition of Crops
100.0% 90.0% 80.0% 70.0% Ash Lignin Carbohydrates Lipids Proteins

Ratio [%]

60.0% 50.0% 40.0% 30.0% 20.0% 10.0% 0.0% Corn Corn Stover Soybean Alfalfa Switchgrass

Crops

Some Early Findings
• Corn stover removal provides less soil organic carbon but reduces nitrous oxide emissions from soil and also reduces inorganic nitrogen losses by leaching. • Winter cover crop enhances soil organic carbon, reduces nitrous oxide emissions from soil and also reduces inorganic nitrogen losses by leaching.

• Utilizing lignin to generate electricity and steam further reduces crude oil use and greenhouse gas emissions associated with producing feedstocks for biobased products. • Results from CENTURY are very location specific: ―All Biomass Is Local‖

TOWARD A SUSTAINABLE ECONOMY

―ALL BIOMASS IS LOCAL‖


								
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