What Should We Expect from Biofuels?

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What Should We Expect from Biofuels?
USDA REE Energy Summit

• Robert C. Brown
• Bioeconomy Institute
• Department of Mechanical Engineering
• Iowa State University
• Ames, IA

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Concerns about global climate change will soon
drive energy and land use policies
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Whats the rush to get off imported petroleum?
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Two Kinds of Energy
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• Primary Energy Sources

• Primary Energy Sources - forms of energy as they
  are found in the natural environment

• Energy carriers

• Energy carriers - convenient and clean-burning
  forms of energy that are readily transported,
  stored, and utilized in distributed applications

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Primary Energy Sources
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Energy Carriers
Coal
Petroleum
Natural Gas
Tar sands
Oil shale
Methane hydrates
Nuclear
Wind
Hydropower and wave energy
Geothermal
Tidal energy
Solar electric
Photosynthesis (bioenergy)
Liquid Hydrocarbons
Hydrogen
Methane
Ammonia
Dimethyl ether
Ethanol
Methanol
Butanol
Fischer-Tropsch Liquids
Furans
Esters
Terpenes
Electricity
FOSSIL
RENEWABLE
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Fossil Energy vs. Renewable Energy
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Fossil energy is more highly concentrated
Renewable energy is obtained by harnessing and
concentrating energy flows in the biosphere
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Economies of Alternative Fuels
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• Dollar economy the amount of money expended in
  driving a unit distance (/km)
• Fuel economy the amount of primary energy
  consumed in driving a unit distant (MJ/km)
• Carbon economy the amount of carbon dioxide
  (equivalence) emitted during both production and
  utilization of fuel per unit distance driven (g
  CO2/km)
• Water economy the amount of water used to
  produce a fuel (L/km)

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Goal is to economize all four metrics
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Current approach to biofuels only economizes on
GHG emissions and water usage
Source Gifford and Brown (2010)
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What is the Perfect Energy Carrier for
Transportation Fuel?
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• Liquid at ambient conditions
• Immiscible in water
• Low toxicity
• High energy density
• Cold weather operability
• Stable during long-term storage
• Efficient production from a primary energy source

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Drop-In Fuels
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• Fully compatible with existing fuel
  infrastructure
• Hydrocarbons (alkanes and aromatics)
• Possibly butanol
• Are drop in fuels
• also the perfect fuel?
• Close enough

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Closer Look at Some Energy Carriers
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Diesel from domestic petroleum
Liquid Hydrocarbons
Hydrogen
Methane
Ammonia
Dimethyl ether
Ethanol
Methanol
Butanol
Fischer-Tropsch Liquids
Furans
Esters
Terpenes
Electricity
Compressed natural gas
Battery electric vehicles
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Gasoline from Domestically Produced Petroleum
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• Exploit domestic resources like the Bakken
  Formation in North Dakota and Montana
• Estimated recoverable reserves in Bakken recently
  increased from 150 million barrels to 3 to 4.3
  billion barrels
• Largest U.S. oil reserves outside Alaska

Six months of U.S. petroleum demand
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Compressed Natural Gas
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Pros
U.S. has 1,530 trillion cubic feet of natural gas
Can be burned in standard automobile engines
Cleanest fossil fuel
Cons
Widely used for other purposes
Not as convenient as liquid fuels
Produces greenhouse gas emissions
Would deplete domestic supplies in less than 40
years
EAI estimate
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What was T. Boone Pickens Thinking?
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Natural Gas Prices 2000-2008
http//www.neb.gc.ca/clf-nsi/rnrgynfmtn/prcng/ntrl
gs/cndnmrk-eng.html
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How About Electricity as Fuel?
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• Least expensive alternative fuel
• Potential for very low greenhouse gas emissions
  (depending upon energy source)
• Attractive vehicle platform

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The Problem with Batteries

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Energy Storage Technology Energy Cost ( per mile) Storage System Weight (kg) Storage System Capital Cost ()
Gasoline 0.13 30 68
E85 0.14 50 77
Compressed NG 0.08 120 300
Lead-acid battery 0.03 3200 22,000
Li-ion battery 0.03 480-2200 38,000-140,000
Energy Storage Technology Energy Cost ( per mile) Storage System Weight (kg) Storage System Capital Cost () Vehicle Operating Cost ( per mile)
Gasoline 0.13 30 68 0.25
E85 0.14 50 77 0.27
Compressed NG 0.08 120 300 0.29
Lead-acid battery 0.03 3200 22,000 0.27
Li-ion battery 0.03 480-2200 38,000-140,000 0.51
Cost of gasoline assumed to be 3.00 per gallon.
Storage system sized for 250 mile driving range.
Weight based on full fuel tanks. Operating costs
do not account for effect of storage weight on
vehicle range. Large range for lithium-ion
battery performance reflects range of claims
among various proponents and developers.
Source R. C. Brown
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We must learn to harvest energy flows in the
biosphere to provide us both food and fuel in a
sustainable manner.
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Why are we producing biofuels?
Annual energy resource Exajoules
Solar 2,700,000
Wind 2,300
Photosynthetic fixation 3,000
Annual energy consumption
Electricity 60
Primary energy use 470
Brown, expected release December 2009
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Political Challenges to Biofuels
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• Food vs. fuel debate
• Proposals to include indirect land use change in
  low carbon fuel standards

Food not FUEL
LCFS
iLUC
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Food vs. Fuel Debate Laid to Rest
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• All available evidence suggests that biofuels
  had a relatively small contribution to the 2008
  spike in agricultural commodity pricesU.K.
  Department of Environment, Food and Rural Affairs
  (Mar 2010)
• Ethanol production is just one of seven sources
  of commodity price inflation. The rise in global
  demand, energy prices, speculation, the weak
  dollar export restrictions and poor weather also
  contributed to the surge in corn prices...Scott
  Faber, Grocers Manufacturers Association (Jan
  2009)

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Indirect Land Use Change (ILUC) in a nutshell
Farmers in the developing world will burn down
the worlds rain forests or plow natural
grasslands to replace lost food imports, causing
net increase in greenhouse gas emissions.
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Biofuels have been mandated to have Lower
Greenhouse Emissions than Petroleum-Derived
Gasoline
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Lifecycle Greenhouse Gas Thresholds for Biofuels
as Specified by the 2007 Energy Independence and
Security Act (EISA) (Percent reduction relative
to 2005 gasoline baseline).
Renewable fuel 20
Advanced biofuel 50
Biomass-derived diesel 50
Cellulosic biofuel 60
Source EPA 2009
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ILUC Could be Game Changing
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Changes in Greenhouse Gas Emissions Compared to
Petroleum-Derived Gasoline
Source US EPA (2009)
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No Correlation Between Deforestation Rate and
Sugarcane Ethanol Production
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United Nations Food and Agriculture Organization
(deforestation data) and Brazilian Ministry of
Agriculture (ethanol production data)
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No Correlation Between Deforestation Rate and
Soybean Prices
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Source United Nations Food and Agriculture
Organization (deforestation data) and Index Mundi
(soybean price data)
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No Correlation Between Deforestation Rate and
Beef Prices
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Source United Nations Food and Agriculture
Organization (deforestation data) and Index Mundi
(beef price data)
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No Correlation Between Deforestation Rate and
Food Price Index
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Source United Nations Food and Agriculture
Organization (deforestation data) and Index Mundi
(Food Price Index)
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Corn Exports Actually Increased During Period of
Biofuels Land Use Change
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Source USDA
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Deforestation has no simple correlate
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field researchconsistently finds that land-use
change and associated carbon emissions are driven
by interactions among cultural, technological,
biophysical, political, economic, and demographic
forces within a spatial and temporal context
rather than by a single crop market. Kline, K.
L. and Dale, V. H. (2008) Biofuels Effects on
land and fire Letter to the editor, Science 321,
199.
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Latest Opinion from the EPA
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• Modern corn ethanol plants, biodiesel plants, and
  cellulosic ethanol plants all comply with the
  mandated GHG reductions
• What changed in a years time?
• as the state of scientific knowledge continues
  to evolve in this area, the life cycle GHG
  assessments for a variety of fuel pathways are
  likely to be updated.
• These updates included
• new studies that showed crop yields to increase
  with higher crop prices, which reduces demand for
  new land
• new research that shows distillers dried grains
  to be an efficient animal feed, meaning corn
  demand and exports as a result of biofuels
  agriculture are not as impacted as originally
  assumed and
• new pasturelands are likely to be established
  from existing grasslands rather than from
  destruction of forestland.

EPA (2010) EPA finalizes regulations for the
National Renewable Fuel Standard program for 2010
and beyond, Office of Transportation and Air
Quality, EPA-420-F-10-007, February. Available on
the Web at http//www.epa.gov/otaq/renewablefuels
/420f10007.pdf (accessed March 15, 2010).
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Real Problem Unsustainable Food Agriculture
Around the World
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Land use change due to U.S. biofuels production 10.8 million ha (total)
Land lost to agriculture due to soil degradation 510 million ha (annually)
Searchinger (2008) International Food Policy
Institute
Desertification Photo credit Asian Development
Bank
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Three distinct approaches to advanced biofuels
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• Biochemical based conversion of cellulosic
  biomass to ethanol
• Thermochemical based conversion of cellulosic
  biomass to a variety of biofuels
• Lipid-rich biomass converted to biodiesel or
  synthetic diesel (hydrocarbon-based fuel)

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Biochemical based cellulosic ethanol
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• Uses enzymes and microorganisms to convert
  biomass into ethanol
• Focus of the last thirty years of federal
  research
• Builds upon technology developed for grain
  ethanol industry

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Biochemical platform Unlocking the worlds
carbohydrate reservoir through biotechnology
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Glycosidic bond
Starch ? 1-4 linked glucan
Glycosidic bond
Cellulose ? 1-4 linked glucan
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Why is cellulose so difficult to turn into
fermentable sugars?
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• Starch is a storage polysaccharide designed by
  nature as a food reservoir
• Cellulose is a structural polysaccharide, part of
  a lignocellulosic composite designed by nature to
  resist degradation

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Thermochemical-based biorefineries
Biobased fuels and chemicals
Catalytic Reactor
Gasifier
Gas Cleaning
Syngas
Gasification
Air
Diesel Fuel
Steam
Fast Pyrolysis
Bio-oil vapor
Pyrolyzer
Hydrogen
Steam Reformer
Bio-Oil Recovery
Hydrocracker
Low molecular weight compounds
High molecular weight compounds
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Gasification Platform
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• Advantages (compared to biochemical platform)
• Tolerates relatively dirty biomass feedstock
• Produces uniform intermediate product (syngas)
• Proven method for cracking the lignocellulosic
  nut
• Allows energy integration in biorefinery
• Disadvantages (compared to biochemical platform)
• Gas cleaning technologies still under development
• Synfuel processing occurs at high pressures

5 tpd gasification plant at BECON
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Gasification Platform
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• Research at ISU
• Gasification at process development unit and
  pilot scales
• Gas clean-up
• Syngas burner design
• Techno-economic analysis
• Catalytic synthesis to Fischer Tropsch liquids
  and ethanol

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Fast Pyrolysis
Fast pyrolysis - rapid thermal decomposition of
organic compounds in the absence of oxygen to
produce predominately liquid product
Biochar
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Py Products
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• Gas non-condensable gases like carbon dioxide,
  carbon monoxide, hydrogen
• Solid mixture of inorganic compounds (ash) and
  carbonaceous materials (charcoal)

• Liquid mixture of water and organic compounds
  known as bio-oil recovered from pyrolysis vapors
  and aerosols (smoke)

Bio-oil
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Fast Pyrolysis Platform
USDA REE Energy Summit

• Advantages include
• Liquid fuel
• Decoupled conversion processes
• Easier to transport than biomass or syngas
• Disadvantages
• High oxygen and water content makes bio-oil
  inferior to petroleum-derived fuels
• Phase-separation and polymerization and
  corrosiveness make long-term storage difficult

Fluid bed
Free fall
Auger
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Lipid-Based Biofuels
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• Oil Palm High yielding but there are concerns
  about encroachment of palm oil plantations on
  tropical rainforests.
• Jatropha Grows on waste lands with yields up to
  200 gal/acre but it is not a domesticated crop.
• Jojoba Grows in deserts to yield up to 200
  gal/acre of waxy ester but it is very expensive.
• Microalgae High yielding (up to 5500 gal/acre)
  and suitable for waste lands but economical
  harvest and extraction not yet developed.
• Salicornia Salt-tolerant but yields only 100
  gal/acre.

Salicornia Bigelovii
Jatropha
Jojoba
Microalgae
Oil Palm
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Lipids are close to hydrocarbons
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Triglycerides three fatty acids attached to
glycerol backbone found in oil seeds and
microalgae
Waxy esters fatty acid and fatty alcohol
combination found in jojoba seeds
Isoprene building block of terpenes natural
hydrocarbons usually produced in small quantities
in plants and microorganisms
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Looking Forward
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Much of the current debate on bioenergy
obscures the sectors huge potential to reduce
hunger and poverty If we get it right, bioenergy
provides us with a historic chance to
fast-forward growth in many of the worlds
poorest countries, to bring about an agricultural
renaissance and to supply modern energy to a
third of the worlds population. Jacques
Diouf, Director-General, UN Food and Agriculture
Organization
Highest Annual Precipitation
Highest Annual Solar Irradiance
Highest Human Development Need
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Potential Show Stopper Poor Fertility of Soils
in the Tropics
Shaded areas are among the worlds most weathered
and leached soils (Oxisols and Ultisols)
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A New Kind of Agriculture Land Application of
Biochar to Build Soils
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Biochar Byproduct of Fast Pyrolysis and
Gasification
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Terra Preta Soils

• Created hundreds of years ago by pre-Colombian
  inhabitants of Amazon Basin
• Result of slash and char agriculture
• Much higher levels of soil organic carbon
• Far more productive than undisturbed oxisol soils

Applied to the land, biochar serves as both soil
amendment and carbon sequestration agent
Glaser et al. 2001. Naturwissenschaften (2001)
883741
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Greenhouse gases reduced by carbon storage in
agricultural soils
Carbon Stored (lb/acre/yr)
Char from pyrolyzing 75 of corn stover (assuming
corn yield of 180 bu/acre and 25 charcoal yield)
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Is merely reducing GHG emissions enough?
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Future of Fuels?
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• Secretary of Energy Steven Chu advocates solar
  fuels without inefficiency of biomass
  production
• Microorganisms absorb sunlight, water, and CO2
  and pump out transportation fuels
• Artificial photosynthesis accomplish both charge
  separation and chemical synthesis
• Solar thermochemical fuelshigh temperature solar
  concentrators with chemical boilers decompose
  water and/or CO2 as syngas for subsequent fuel
  synthesis

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Questionshttp//www.washingtonpost.com/wp-dyn/cont
ent/article/2010/04/22/AR2010042205126_pf.html
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