CELLULOSIC ETHANOL & SUSTAINABILITY: THERE IS NO “FOOD

VS. FUEL” CONFLICT

Bruce E. DaleDept. of Chemical Engineering & Materials Science

Michigan State Universitywww.everythingbiomass.org

Presented at:American Chemical Society Meeting

Chicago, IllinoisMarch 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 SupplyMaterial

(billion kg)

Africa Asia Europe North

America

Central

America

Oceania South

America

Sub

Total

Corn

stover0.0 33.9 28.6 134 0.0 0.2 7.2 203.6

Barley

straw0.0 2.0 44.2 9.9 0.2 1.9 0.3 58.5

Oat straw 0.0 0.3 6.8 2.8 0.0 0.5 0.2 10.6

Rice

straw20.9 668 3.9 10.9 2.8 1.7 23.5 731.3

Wheat

straw5.3 145 133 50.1 2.8 8.6 9.8 354.4

Sorghum

straw0.0 0.0 0.4 6.9 1.2 0.3 1.5 10.3

Bagasse 11.7 74.9 0.01 4.6 19.2 6.5 63.8 180.7

Subtotal 38.0 924 216 219 26.1 19.7 106.3 1549.4

• 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

Why are Yields Important?

Yields & Photosynthetic Efficiencies of Some Crops

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

PROTEIN TOTAL ENERGY

ANIMAL CLASS (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

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.

Ruminant Animals & Biorefineries

LotsofHay

Mobile Cellulose Biorefinery (a.k.a. Cow)

Stationary Cellulose Biorefinery

Ruminant Bioreactor:

Capacity ~ 40 Gal Fermentor

Biomass Input ~ 26 Lb/Day*

SSCF Bioreactor:

Biomass Input ~ 5,000 Dry Ton/Day= 10 M Dry Lb/Day

Capacity ~ 45 M Gal Fermentor

*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.

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 $/gal

ethanol

$/gal gas

equivalent

$/gal diesel equiv.

EtOH/

Rankine

$0.60 $0.91 na

EtOH/

GTCC

$0.63 $0.95 na

EtOH/FT/

GTCC

$0.72 $1.09 $1.02

EtOH/Protein/

Rankine

$0.49 $0.74 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

DOE 2005

Cellulosic Biomass

Production

Biomass Conversion Research Lab at

Michigan State Works Here Using AFEX Process

Reactor Explosion

AmmoniaRecovery

BiomassTreatedBiomass

RecycleAmmonia

GaseousAmmonia

Reactor Expansion

AmmoniaRecovery

BiomassTreatedBiomass

Ammonia

GaseousAmmonia

Heat

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

How does AFEX work?

“Absolutely!”

Composition of Crops

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

100.0%

Corn Corn Stover Soybean Alfalfa Switchgrass

Crops

Rat

io [

%] Ash

Lignin

Carbohydrates

Lipids

Proteins

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”