USDA REE Energy Summit
What Should We Expect from
Biofuels?
Robert C. Brown
Bioeconomy Institute
Department of Mechanical Engineering
Iowa State University
Ames, IA
Concerns about global climate
change will soon drive energy and
land use policies
USDA REE Energy Summit
What’s the rush to get off imported
petroleum?
Who has the oil?
(bbs - billions of barrels)
Russia
Norway
72 bbls
Azerbaijan
Kazakhstan
Canada
39 bbls
16 bbls
United States
Iraq
21 bbls
115 bbls
Iran
Mexico
132 bbls
Columbia
Venezuela
China
17 bbls
India
Vietnam
Malasia
Kuwait
Egypt
Algeria Libya Sudan
39 bbls
99 bbls
77 bbls
Nigeria
Qatar
35 bbls
Equador
Brazil
Who uses the oil?
(thousand s of barrels per day)
6,000 +
3,000 - 5,999
2,000 - 2,999
1,000 - 1,999
0 - 999
Saudi Arabia
262 bbls
Angola
15 bbls
United Arab Emirates
97 bbls
USDA REE Energy Summit
Two Kinds of Energy
• Primary Energy Sources - forms of energy as
they are found in the natural environment
• Energy carriers - convenient and “cleanburning” forms of energy that are readily
transported, stored, and utilized in
distributed applications
RENEWABLE
FOSSIL
USDA REE Energy Summit
Primary Energy Sources
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
USDA REE Energy Summit
Fossil Energy vs. Renewable Energy
Renewable
energy is
obtained by
harnessing and
concentrating
energy flows in
the biosphere
Energy Flux (watts per square meter)
Fossil energy is
more highly
concentrated
10000
1000
100
10
1
0.1
USDA REE Energy Summit
Economies of Alternative Fuels
• 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)
USDA REE Energy Summit
Goal is to economize all four metrics
Wells-to-Wheels (WTW) Analysis of Various Transportation Fuels
18
16
14
12
Water Usage (L/km)
Energy Usage (MJs/km)
GHG Emissions (gCO2e/km)/100
Operating Cost (cents/km)
Current approach to biofuels only
economizes on GHG emissions
and water usage
10
8
6
4
2
0
Source: Gifford and Brown (2010)
USDA REE Energy Summit
What is the Perfect Energy Carrier
for Transportation Fuel?
•
•
•
•
•
•
•
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
USDA REE Energy Summit
Drop-In Fuels
• Fully compatible with existing fuel
infrastructure
– Hydrocarbons (alkanes and aromatics)
– Possibly butanol
• Are drop in fuels
also the “perfect fuel?”
– Close enough
USDA REE Energy Summit
Closer Look at Some Energy Carriers
Liquid Hydrocarbons
Hydrogen
Methane
Ammonia
Dimethyl ether
Ethanol
Methanol
Butanol
Fischer-Tropsch Liquids
Furans
Esters
Terpenes
Electricity
Diesel from
domestic petroleum
Compressed
natural gas
Battery
electric
vehicles
USDA REE Energy Summit
Gasoline from Domestically Produced
Petroleum
• 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
USDA REE Energy Summit
Compressed Natural Gas
Pros
Cons
U.S. has 1,530 trillion cubic
feet of natural gas*
Can be burned in standard
automobile engines
Widely used for other
purposes
Not as convenient as liquid
fuels
Cleanest fossil fuel
Produces greenhouse gas
emissions
*EAI estimate
USDA REE Energy Summit
What was T. Boone Pickens Thinking?
Natural Gas Prices
2000-2008
http://www.neb.gc.ca/clf-nsi/rnrgynfmtn/prcng/ntrlgs/cndnmrk-eng.html
USDA REE Energy Summit
How About Electricity as Fuel?
• Least expensive alternative fuel
• Potential for very low greenhouse gas emissions
(depending upon energy source)
• Attractive vehicle platform
Petroleum-based Gasoline
Natural Gas Combined Cycle Battery Electric
USDA REE Energy Summit
The Problem with Batteries
Energy Storage
Technology
Gasoline
E85
Compressed NG
Lead-acid battery
Li-ion battery
Energy Cost
($ per mile)
0.13
0.14
0.08
0.03
0.03
Storage
System
Weight
(kg)
30
50
120
3200
480-2200
Vehicle
Storage
Operating
System
Cost
Capital Cost
($ per mile)
($)
0.25
68
0.27
77
0.29
300
0.27
22,000
0.51
38,000140,000
*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
USDA REE Energy Summit
Why are we producing biofuels?
We must learn to harvest energy flows
in the biosphere to provide us both
food and fuel … in a sustainable
manner.
Annual energy resource
Exajoules
Solar
2,700,000
Wind
2,300
Photosynthetic fixation
3,000
Annual energy consumption
Electricity
Primary energy use
60
470
Brown, expected release December 2009
USDA REE Energy Summit
Political Challenges to Biofuels
• Food vs. fuel debate
• Proposals to include indirect land use
change in low carbon fuel standards
USDA REE Energy Summit
Food vs. Fuel Debate Laid to Rest
• “[All] available evidence suggests that biofuels had a
relatively small contribution to the 2008 spike in
agricultural commodity prices…”–U.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)
Indirect Land Use Change (ILUC)
in a nutshell
Farmers in the developing world will burn
down the world’s rain forests or plow
natural grasslands to replace lost food
imports, causing net increase in
greenhouse gas emissions.
USDA REE Energy Summit
Biofuels have been mandated to have
Lower Greenhouse Emissions than
Petroleum-Derived Gasoline
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
Advanced biofuel
Biomass-derived diesel
Cellulosic biofuel
20%
50%
50%
60%
Source: EPA 2009
USDA REE Energy Summit
ILUC Could be Game Changing
Changes in Greenhouse Gas Emissions Compared to Petroleum-Derived Gasoline
Corn EtOH
Corn EtOH
Corn EtOH NG Best Corn EtOH Corn EtOH Biomass Sugarcane Switchgrass Corn Stover
NG
Case
Coal
Biomass
CHP
EtOH
EtOH
EtOH
150%
125%
100%
75%
Direct Contributions
Direct and Indirect Contributions
2007 EISA LCFS Requirement for Cellulosic Biofuels
50%
25%
2007 EISA LCFS Requirement for Corn Ethanol
0%
-25%
-50%
Source: US EPA (2009)
USDA REE Energy Summit
Deforestation rate (square kilometers per year)
No Correlation Between Deforestation
Rate and Sugarcane Ethanol Production
35,000
30,000
25,000
y = 1050.6x + 14252
R² = 0.0111
20,000
15,000
10,000
5,000
0
2.5
3
3.5
4
4.5
5
Sugarcane ethanol production (billion gallons)
United Nations Food and Agriculture Organization (deforestation data)
and Brazilian Ministry of Agriculture (ethanol production data)
USDA REE Energy Summit
Deforestation rate (square kilometers/year)
No Correlation Between Deforestation
Rate and Soybean Prices
35,000
30,000
25,000
20,000
15,000
10,000
5,000
y = 766.77x + 13306
R² = 0.0188
0
$4.00 $4.50 $5.00 $5.50 $6.00 $6.50 $7.00 $7.50 $8.00
Soybean price (dollars per bushel)
Source: United Nations Food and Agriculture Organization (deforestation data) and Index Mundi (soybean price data)
USDA REE Energy Summit
Deforestation Rate (square kilometers/year
No Correlation Between Deforestation
Rate and Beef Prices
35,000
30,000
25,000
20,000
15,000
10,000
y = -101.45x + 28218
R² = 0.099
5,000
0
70.00
80.00
90.00
100.00
110.00
120.00
130.00
Beef Price (cents per pound)
Source: United Nations Food and Agriculture Organization
(deforestation data) and Index Mundi (beef price data)
USDA REE Energy Summit
Deforestation rate (square kilometers per year)
No Correlation Between Deforestation
Rate and Food Price Index
35,000
30,000
25,000
20,000
15,000
10,000
y = -64.819x + 24203
R² = 0.0163
5,000
0
75.00
80.00
85.00
90.00
95.00 100.00 105.00 110.00 115.00
Food Price Index
Source: United Nations Food and Agriculture
Organization (deforestation data) and Index Mundi
USDA REE Energy Summit
Corn Exports Actually Increased During
Period of Biofuels Land Use Change
Corn Usage (million bushels)
14000
Feed
Ethanol
Export
Other
12000
10000
8000
6000
4000
2000
0
97/98
99/00
01/02
Year
03/04
05/06
07/08
Source: USDA
USDA REE Energy Summit
Deforestation has no simple correlate
…field research…consistently 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.
USDA REE Energy Summit
Latest Opinion from the EPA*
• Modern corn ethanol plants, biodiesel plants, and cellulosic
ethanol plants all comply with the mandated GHG reductions
• What changed in a year’s 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).
USDA REE Energy Summit
Real Problem: Unsustainable Food
Agriculture Around the World
Land use change due to U.S.
biofuels production*
Land lost to agriculture due
to soil degradation**
10.8 million ha
(total)
5–10 million ha
(annually)
*Searchinger (2008)
**International Food Policy Institute
Desertification
Photo credit: Asian Development Bank
USDA REE Energy Summit
Three distinct approaches to
advanced biofuels
• 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)
USDA REE Energy Summit
Biochemical based cellulosic ethanol
• 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
USDA REE Energy Summit
Biochemical platform: Unlocking the
world’s carbohydrate reservoir through
biotechnology
Starch
Glycosidic
bond
 1-4 linked glucan
Cellulose
 1-4 linked glucan
Glycosidic
bond
USDA REE Energy Summit
Why is cellulose so difficult to turn into
fermentable sugars?
• 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
USDA REE Energy Summit
Gasifier
Gas Cleaning
Catalytic
Reactor
Biobased
fuels and
chemicals
Syngas
Air
Diesel Fuel
Steam
Pyrolyzer
Bio-oil vapor
Bio-Oil
Recovery
Steam
Reformer
Low molecular weight compounds
High molecular weight compounds
Hydrogen
Hydrocracker
Fast Pyrolysis
Gasification
Thermochemical-based biorefineries
USDA REE Energy Summit
Gasification Platform
• 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
USDA REE Energy Summit
Gasification Platform
• 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
Raw Syngas
Gasifier
Biomass
Oxygen/Steam
Particulate
Removal
Biofuel
Sulfur Nitrogen Catalytic
Tar
Alkali
Removal Removal Removal Removal Synthesis
Fast Pyrolysis
Fast pyrolysis - rapid
thermal decomposition
of organic compounds
in the absence of
oxygen to produce
predominately liquid
product
Biochar
USDA REE Energy Summit
Py Products
• 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
Bio-oil
compounds known as
bio-oil recovered from
pyrolysis vapors and
aerosols (smoke)
USDA REE Energy Summit
Fast Pyrolysis Platform
• 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
40
Fluid bed
Free fall
Auger
USDA REE Energy Summit
Lipid-Based Biofuels
•
•
•
•
•
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.
Oil Palm
Jatropha
Jojoba
Microalgae
Salicornia
Bigelovii
USDA REE Energy Summit
Lipids are “close to hydrocarbons”
H3C
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
H3C
H3C
C
H2
C
H2
C
H2
H2
C
H2
C
H2
C
C
H2
C
H2
C
H2
H2
C
H2
C
H2
C
C
H2
C
H2
C
H2
H2
C
H2
C
H2
C
C
H2
C
H2
C
H2
H2
C
H2
C
C
H2
C
H2
H2
C
C
H2
H2
C
H2
C
C
H2
C
H2
H2
C
C
H2
H2
C
H2
C
H2
C
C
H2
C
H2
C
H2
H2
C
H2
C
H2
C
C
H2
C
H2
C
H2
H2 O
C C O
CH2
H2 O
C C O
CH
H2 O
C C O
CH2
O
CH3 (CH2) 7
C
H
C
(CH2)m
CH3 (CH2) 7
C
C
H
H
n=8,10,12,14
m=7,9,11,13
Isoprene:
building block of terpenes;
natural hydrocarbons usually
produced in small quantities in
plants and microorganisms
(CH2) n
O
CH3
C
H
C
H
H
C
C
H
H
C
H
USDA REE Energy Summit
Looking Forward
‘Much of the current debate on bioenergy […] obscures the sector’s huge potential to reduce
hunger and poverty …If we get it right, bioenergy provides us with a historic chance to fastforward growth in many of the world’s poorest countries, to bring about an agricultural
renaissance and to supply modern energy to a third of the world’s population.”
–Jacques Diouf, Director-General, UN Food and Agriculture Organization
Highest Annual Solar Irradiance
Highest Annual Precipitation
Highest Human Development Need
USDA REE Energy Summit
Potential Show Stopper:
Poor Fertility of Soils in the Tropics
Shaded areas are among the world’s most weathered
and leached soils (Oxisols and Ultisols)
USDA REE Energy Summit
A New Kind of Agriculture: Land
Application of Biochar to Build Soils
Increases:
Nutrient Availability
Microbial Activity
Soil Organic Matter
Water Retention
Crop Yields
Decreases:
Biochar: Byproduct
of Fast Pyrolysis
and Gasification
Fertilizer Needs
Greenhouse Gas Emissions
Nutrient Leaching
Erosion
USDA REE Energy Summit
Terra Preta Soils
Terra Preta
Oxisol
• Created hundreds of
years ago by preColombian inhabitants
of Amazon Basin
• Result of slash and char
agriculture
• Much higher levels of
soil organic carbon
• Far more productive
than undisturbed oxisol Applied to the land, biochar serves as both
soil amendment and carbon sequestration
soils
agent
Glaser et al. 2001. Naturwissenschaften (2001) 88:37–41
USDA REE Energy Summit
Carbon Stored (lb/acre/yr)
Greenhouse gases reduced by carbon
storage in agricultural soils
Char from pyrolyzing 75% of corn stover (assuming
corn yield of 180 bu/acre and 25% charcoal yield)
USDA REE Energy Summit
Is merely reducing GHG emissions enough?
“Desire to reduce airborne CO2 raises
the question of whether CO2 could be
drawn from the air artificially. There are
no large-scale technologies for CO2 air
capture now… At $100/tC, the cost of
removing 50 ppm of CO2 is ~$10 trillion.”
James Hansen
NASA Goddard Institute for Space
Studies
Scrub CO2 From the Air, Win $25
Million -- But How?
James Owen
for National Geographic News
February 16, 2007
It's Richard Branson's 25-million-U.S.dollar question: Can someone develop an
effective, economical way to reduce
global warming by sucking greenhouse
gases from the atmosphere?
Last week the British tycoon and former
U.S. Vice President Al Gore announced
the Virgin Earth Challenge. The program
offers the biggest science prize in history
to anyone who can come up with a
commercially viable system for removing
human-produced carbon dioxide (CO2)
from the atmosphere.
USDA REE Energy Summit
Future of Fuels?
• 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 fuels—high temperature solar
concentrators with “chemical boilers” decompose water and/or
CO2 as syngas for subsequent fuel synthesis
USDA REE Energy Summit
Questionshttp://www.washingtonp
ost.com/wpdyn/content/article/2010/04/22/A
R2010042205126_pf.html