Biofuels: A High-Beam Perspective
Lee R. Lynd
Thayer School of Engineering & Department of Biology, Dartmouth
Mascoma Corporation
October 10, 2007
1
Imagining a Sustainable World
Sustainable
Resources
Primary
Intermediates
Sunlight
Secondary
Intermediates
Animals
Biomass
Organic
Fuels
Ocean/hydro
Transport.
Electricity
Hydrogen
Materials
Organic
Batteries
Minerals
2
Motors/
Lights
Heat
Geothermal
Choices
Food
Energy
Wind
Nuclear
Human
Needs
Sole Supply
Inorganic
Dimensions of well being for human society…
Sustainability
•Air •Water
Prosperity
• Rural/farm
• Poverty
• Balance
of payments
• Technology
export
Sustainable
Resources
•Soil
•Nutrient cycles
Primary
Intermediates
Sunlight
•Climate
Secondary
Intermediates
Ocean/
hydro
Food
Organic
Fuels
Energy
Motors/
Lights
Heat
Electricity
Hydrogen
• Oil: Magnet
for conflict
• Policy
compromises
Democratize
energy supply
Materials
Organic
Batteries
Minerals
Peace
Transport.
Geotherm.
Nuclear
Human
Needs
Animals
Wind
Biomass
•Habitat/
Biodiversity
Inorganic
… determined to a large extent by resource access & utilization -today & always
Convergence of factors makes this critical now - defining challenge of our time
3
Biomass Energy:
Dimensions of Evaluation, Inquiry & Envisioning
End-Uses & Feedstocks
What roles should biomass play in a sustainable world?
What forms of biomass are most promising?
Technology
What are the options for producing energy from cellulosic biomass ?
How do these compare - to each other, current energy supply technologies?
Resource & Environmental
Are there environmental benefits that might be realized?
Could enough biomass be produced to meaningfully address sustainability
& security challenges without compromising other important objectives?
4
End-Uses & Feedstocks
What roles should biomass play in a sustainable world?
What forms of biomass are most promising?
5
Hierarchy of Biomass End-Uses
Availability of Alternatives
End Use
NonSustainable
Sustainable
Biomass
Uniquely
Suited?
Size of
Demand
(relative)
Food (& Feed)
No
No
Yes
Large
Organic
Materials
Yes
No
Yes among
sustainable
Small
Transportation Energy Storage
6
Large
Liquid @
1atm
Yes
No
Yes among
sustainable
Non-liquid
Yes
Yes
No
Electricity
Yes
Yes
No
Large
Heat
Yes
Yes
No
Large
Biofuel Feedstock & Product Options
Starch-rich (grains)
• (e.g.) corn
Oil Seeds
• soy (US)
• rapeseed (EU)
Sugar-rich
• cane (Brazil)
• sugar beets (EU)
Cellulosic
Residues
• stalks, cobs, husks
• paper sludge
Crops
• switchgrass
• short rotation trees
7
{
{
{
{
Ethanol, or other alcohols & CO2
Animal feed
Coproducts
Biodiesel
Animal feed
Glycerin
Ethanol, or other alcohols & CO2
Coproducts
Process energy
(Electricity &/or
Lignocellulose residue
other coproducts)
{
{
Ethanol, or other alcohols, fuels & CO2
Coproducts
Process energy
Electricity &/or
Lignin-rich residues
other coproducts
Aquatic
• Not sufficiently defined to allow evaluation
• Worthy of investigation
Biomass Feedstocks, Especially Cellulosic,
are Cost Competitive with Conventional Energy Sources
Energy Carrier
Price
Common
$/GJ
Fossil
Petroleum
$65/bbl
Natural gas
$7.50/scf
Coal
$20/ton
w/ carbon capture @ $100/ton C
$11.3
$7.9
$0.9
$3.5
$0.045/kWh
$11.3
$0.23/lb
$2.30/bu
$50/tonne
$13.8
$6.6
$3.0
Some < 0
Electricity
Biomass
Soy oil
Corn kernels
Cellulosic cropsa
Cellulosic residues
a e.g.
switchgrass, short rotation poplar
At $3/GJ, the purchase price of cellulosic biomass is competitive with oil at $17/bbl.
8
Comparative Land Productivity of Biofuel Options
402
Biofuel Yield (GJ fuel/ha)
400
350
Cellulosic
Ethanol
300
Long-term
productivity
250
Ethanol from
Corn/Maize
(kernels)
200
150
100
50
Biodiesel
(soy)
Near-term
productivity
134
89
16
0
Crop Yields (U.S.)
Near-term celllulosic: 5 dry ton/acre
Long-term cellulosic: 15 dton/acre
Corn yield: 160 bushel/acre
Soy yield: 42 bushel/acre
9
Fuel Yields
Cellulosic ethanol from RBAEF
Corn ethanol: 2.8 gal/bushel
Soy oil: 18% of bean (dry basis)
Biodiesel yield: 0.95 kg/kg soy oil
Different Plant Feedstocks are Responsive to Different Objectives
Large Scale
Production
Per
unit
Total
Fossil Fuel
Low Cost Fuels
(feedstock &
Rural
Petroleum Displacement/
GHG
conversion)
Economic
Displacement
Soil
Reductions Fertility
Development
(Security)
& Ag.
Now Future Per unit Total Per unit Total
Now
Future
Ecology
Cellulosic
Starch-rich
Sugar-rich
Oil seed
Ratings:
excellent
very good
good
fair
poor
10
Cellulosic biomass is the focus of all studies foreseeing
(very) large-scale widespread energy supply from plants.
• Environmentally benign/beneficial production
• Low purchase cost
• Large potential scale of production
Cellulosic Biomass
Structural part of plant matter - not seeds, not edible
11
Technology
What are the options for producing energy from cellulosic biomass ?
How do these compare - to each other, current energy supply technologies?
12
Biomass Energy Process Families
Liquid Biofuels
Biomass
(solid)
Pretreatment
Enzymatic/
Microbial
Hydrolysis
Distillation
Sugars
Fermentation
Or
Utilities &
Residue
Processing
Acid Hydrolysis
Thermochemical
Fuels
Biomass
(solid)
Gasification
Or
Pyrolysis
Or
Dedicated
Electricty
Generation
Combustion
Small Molecules
(reactive, fluid phase)
Separation
Catalytic
synthesis
Biotech.
fuels
Treated
Effluents
Hydrogen
FT Fuels
DME
Alcohols
Treated
Effluents
Steam (Rankine) Cycle
Or
Combined Cycle Gas Turbine
Or
Fuel Cell
13
Utilities &
Residue
Processing
Ethanol
Butanol
Electricity
Treated
Effluents
Energy Coproduction Strategies
Thermochemical Fuels
with Electricity
TC Fuel
Production
Heat
Electricity
Generation
Thermochemical Fuels
Electricity
Biofuels with Power
Biofuel
Production
Residues
Heat
Electricity
Generation
Biofuels with
Thermochemical
Fuels
Biofuel
Production
Residues
Heat
TC Fuel
Production
14
Biofuels
Electricity
Biofuels
Thermochemical Fuels
Oil Refining
(Numbers Denote Energy Flows)
Crude Recovery, TS&D
Fuels
100%
TS&D
Refining
100%
77%
96%
15%
(Still gas)
2.2%
9.5%
2.9% (FFE)
10.1% (FFE)
Input Mix
1%
1%
15%
2%
62%
19%
Input Mix
Coal
Residual oil
Natural gas
Electricity
Sources:
External energy inputs/efficiencies: GREET
Refinery outputs: EIA
15
Petrochemicals (3%)
Other
4.4%
Crude
Residual oil
Diesel
Gasoline
Natural gas
Electricity
ƒGasoline (42.0%)
ƒDiesel (23.8%)
ƒJet fuel (8.9%)
ƒLPG (2.6%)
0.4%
19%
4%
71%
6%
Input Mix
Diesel 100%
ƒCoke (5.2%)
ƒResidual oil (4.5%)
ƒAsphalt (3.6%)
ƒLubricants (1.0%)
ƒOther (1.0%)
Required
inputs?
?
TS&D
Refining
Biomass Production, TS&D
Biomass Refining
?
What will
we make
?
What will it cost?
Role of Biomass in America’s Energy Future Project
Co-led with Nathanael Greene (NRDC), 11 institutions
Sponsors: DOE, National Commission on Energy Policy, Energy Foundation
Examined resource and environmental issues
Forecast mature biomass processing technologies
16
Mature Biomass Refining Energy Flows (one of 24 scenarios)
26%
27%
Residue
WWT
Sludge
1%
Biogas 13%
0.1%
Steam Turbine
HRSG
17%
1%
0.1%
22%
35%
19%
GT
Liquid
9% 16%
1%
Gas Cleanup
Cooling/Heat Loss
Other Utilities
Solids
26%
4%
21%
0.6%
2%
Power 1%
FT Gasoline 6%
FT Diesel 10%
POX
2%
96%
54%
Drier
97%
Ethanol
WWT
6%
3%
Distillation
100%
Steam10%
10%
Steam
5%
CBP
100%
Feed Handling
Feedstock
Pretreatment
3%
NH3
1%
THERMOCHEMICAL
Power
3.7%
Power
3.6%
3.7%
FT Synthesis
1.6%
0.9%
Gasification
0.2%
0.1%
0.3%
BIOLOGICAL
Energy out/Ag inputs in:
Ag Inputs (Farming, feedstock transport) ~ 7 %
17
71/7 ≈ 10
Efficiency of Mature RBAEF Process Scenarios
Total
Efficiency
73.3
EtOH/protein/FT
EtOH/protein/GTCC power
69.4
EtOH/protein/Rankine power
61.2
76.5
EtOH/H2
EtOH/FT (1X)/CH4
76.5
EtOH/FT/GTCC power
70.4
EtOH/GTCC power
68.1
61.4
EtOH/Rankine power
H2/GTCC power
64.2
54.9
DME/GTCC power
FT fuels
+ Power
57.7
49.1
32.8
FT/GTCC power
GTCC power
Rankine power
-10
Bioethanol +
Coproducts
79.6
EtOH/FT (recycle)/CH4
0
Power
10
20
30
40
50
60
70
80
Energy out as a % of feedstock LHV
(bars starting below zero indicate a power requirement for the process)
18
EtOH
FT diesel
FT gasoline
DME
H2
CH4
Power
Protein
90
Scenario Comparison: Fuel price variable, power price constant, 5,000 tpd
2002
Crude :
2003
2004
($26/bbl) ($31/bbl) ($42/bbl)
Gasoline: ($0.83/gal) ($1.00/gal)($1.29/gal)
2005
2006
($57/bbl)
($66/bbl)
($75/bbl)
($1.68/gal) ($1.97/gal) ($2.20/gal)
Internal Rate of Return (%)
50%
EtOH-Rankine
EtOH-GTCC
EtOH-FT-GTCC
EtOH-FT(1X)CH4
EtOH-FT(recycle)CH4
Ethanol-H2
EtOHl-Prtn.-Rankin
EtOH-Protein-GTCC
EtOH-Protein-FT
FT-GTCC
DME-GTCC
H2-GTCC
Rankine
GTCC
45%
40%
35%
30%
25%
20%
15%
10%
5%
0%
$5
$10
$15
Fuel Price ($/GJ gasoline equiv.)
19
$20
$0.05/kWh
$0.20/lb protein
35/65 D/E
7.0% loan rate
$44/dry ton
Scenario Comparison: Fuel price variable, power price constant, 5,000 tpd
2002
2003
2004
Crude: ($26/bbl) ($31/bbl) ($42/bbl)
Gasoline: ($0.83/gal) ($1.00/gal)($1.29/gal)
2005
2006
($57/bbl)
($66/bbl)
($75/bbl)
($1.68/gal) ($1.97/gal) ($2.20/gal)
Internal Rate of Return (%)
50%
EtOH-Rankine
EtOH-GTCC
EtOH-FT-GTCC
EtOH-FT(1X)CH4
EtOH-FT(recycle)CH4
EtOH-H2
EtOH-Prtn.-Rankine
EtOH-Protein-GTCC
EtOH-Protein-FT
FT-GTCC
DME-GTCC
H2-GTCC
Rankine
GTCC
45%
40%
ts
uc
d
p ro
co
nd
a
ls)
ue
f
ucts
x
d
a
o
pr
(m
d co
ol
n
n
a
a
ol
eth
han
t
o
i
e
B
Bio
35%
30%
25%
20%
nd p
el s a
u
F
TC
15%
ower
10%
Power
5%
0%
$5
$10
$15
Fuel Price ($/GJ gasoline equiv.)
20
$20
$0.05/kWh
$0.20/lb protein
35/65 D/E
7.0% loan rate
$44/dry ton
17.5
15.5
TC fuels and
Power
Bioethanol and
TC Coproducts
Dedicated
Power
13.5
11.5
9.5
7.5
5.5
3.5
GTCC
Rankine
H2
DME/GTCC
FT/GTCC
EtOH/Protein/FT
EtOH/Protein/GTCC
EtOH/Protein/Rankine
EtOH/H2
EtOH/FT (recycle)/CH4
EtOH/FT (1X)/CH4
EtOH/FT/GTCC
EtOH/GTCC
1.5
-0.5
21
Bioethanol
(max fuels) and
TC Coproducts
EtOH/Rankine
Oil Displacement (GJ/dry ton)
Comparative Petroleum Displacement
Current US Power Mix
Future US Power Mix
Comparative Greenhouse Gas Displacement
22
Bioethanol
(max fuels) and
TC Coproducts
1,400
1,200
TC fuels and
Power
Bioethanol and
TC Coproducts
Dedicated
Power
1,000
800
600
400
GTCC
Rankine
H2
DME/GTCC
FT/GTCC
EtOH/Protein/FT
EtOH/Protein/GTCC
EtOH/Protein/Rankine
EtOH/H2
EtOH/FT (recycle)/CH4
EtOH/FT (1X)/CH4
EtOH/FT/GTCC
0
EtOH/GTCC
200
EtOH/Rankine
GHG Displacement (kg/dry ton)
(Ignoring soil carbon & point source carbon capture for the moment)
Current US Power Mix
Future US Power Mix
Results from ~ two dozen biomass mature technology processing scenarios
support the following working hypotheses
All the most cost-effective scenarios feature biological processing - expected to
be the cheapest way to process the carbohydrate fraction of biomass
However, post biological thermochemical processing is very important
• Responsible for processing ~ 40% of the energy in the original feedstock
• Adds substantially to efficiency, revenues, greenhouse gas displacement
• Strong thermodynamic synergies with biological processing
Production of ethanol in combination with several coproduct combinations is
cost-competitive with gasoline at oil prices > $30/barrel
Biofuels &
coproducts*
Metric
GHG emission reductions**
+++
TF fuels &
power
+++
Relative cost effectiveness
+++
++
+
Petroleum displacement
+++
++
-
*Thermochemical fuels (TF) and/or power and in some cases protein
**Greenhouse gas emission reductions, per ton (or per acre) basis
23
Power
+++
Resource & Environmental
Could enough biomass be produced to meaningfully address sustainability
& security challenges without compromising other important objectives?
Are there environmental benefits that might be realized?
24
Environmental Benefits?
When soil fertility and rural ecology advocates consider replacing row
crops with cellulosic perennials & covercrops, they like what they see
Much lower use of herbicide, pesticides
Radically reduced erosion
Much higher nutrient capture and reduced surface water eutrophication
Enhanced wildlife habitat and biodiversity
Strong potential for recycling mineral nutrients from the processing
facility to the field
Soil carbon accumulation
• Perennial grasses accumulate organic matter at substantial rates
(~1 tonne C/ha/yr) over timeframes from many decades to a few centuries
• Occurs faster with harvest than without - surprising but true
Marked potential to couple and drive these benefits with revitalization
of rural economies
25
Inputs
Biofuel GHG Accounting Revisited
CO2
ƒLiquid fuel
ƒFertilizer
ƒOther
Photosynthesis
Nutrient
recycle
End use
Soil Carbon
Accumulation
Geo/Ocean
Reservoirs
Biomass
CO2
point
source
Biofuel
Coproducts
CO2 point source
Conversion
(e.g. power, feed)
CO2 Equivalent Emission
(% Gasoline base case, per mile, not cumulative)
• Two possibilities for removing
carbon
from the
atmosphere,
each
EtOH
& FT Fuels
&with
Power
EtOH
& Power
carbon
flows
comparable to avoided
Primary
Cycle
0 emissions from fuel substitution
0
+8 GHG levels
•Inputs
Neither is infinite, both buy us +10
time and “lower the hump”of
Coproducts
-56
-4
• Soil carbon accumulation could potentially be coupled with fertility
enhancement,
reclamation of degraded
lands
N recycle
-3
-2
Soil carbon accumulation -43 to -159
CO2 capture, sequestration
-128
26
-33 to -122
-98
Biofuels as Part of a Broader Greenhouse Gas Mitigation Strategy
An Illustrative Example
CO2 Emission Reduction Strategies
A. 1/3 current transport fuel from
cellulosic biofuels, coproduce power
B. 40% electrical power from carbonneutral sources
C. Triple transportation sector efficiency
Biofuels C Sequestration
Opportunities
29.8% remaining
23.3%
45.2%
27.7%
21.1%
6.5%
Soil carbon
27
Point source
Combined
29.8%
remaining
C
24.5%
A
24.5%
B
21.2%
Total CO2 Emissions
Transport & Power Generation
Life Cycle & Resource Issues
Life Cycle Issues
Resource Issues
Usually considered on a per unit basis
Even with positive effects
per acre, an acre devoted
to bioenergy production is
not available exclusively for
Food production
e.g. Per ton, per gallon, per mile, per acre
In general, production & utilization of
cellulosic biomass score very well
• Spectacular greenhouse gas emission benefits from near-zero to potential “GHG sponge”
• Substantial soil fertility, water quality, &
biodiversity benefits when cellulosic perennials,
cover crops are incorporated into ag. systems
Wildlife habitat/biodiversity
Recreation
A greater challenge
NRDC: Several important potential benefits,
no show-stoppers
⎞
Benefits
⎟ × ⎛⎜ Units Utilized ⎞
Benefits (+or−) =
⎟ ⎝
⎠
Unit Utilized ⎠
⎛
⎜
⎜
⎝
28
Resource Sufficiency: Radically Different Conclusions
Large contribution possible & desirable
United States
Biomass will eventually provide over 90% of U.S. chemical and over 50% of
U.S. fuel production (NRC, 1999, Biobased Industrial Products,).
20% of petroleum demand in 2025 (Lovins et al., 2004, Winning the Oil End Game).
1.3 billion tons of biomass could be available in the mid 21st century - 1/3 of current
transport fuel demand (Perlack et al., 2005, “Billion Tons Study”).
50 % current transportation sector energy use, and potentially nearly all gasoline,
by 2050 (Greene et al., 2004, Growing Energy)
Goal of 100 billion gallons of ethanol by 2025 (Ewing & Woolsey, 2006,
A High Growth Strategy for Ethanol)
Worldwide
Biomass becomes the largest energy source supporting humankind by a factor of 2
(Johanssen et al., 1993, Renewables-Intensive Global Energy Scenario).
Biomass potential comparable to total worldwide energy demand (Woods & Hall,
1994; Yamamoto, 1999; Fischer & Schrattenholzer, 2001; Hoogwijk et al., 2005)
29
Resource Sufficiency: Radically Different Conclusions
Large contribution not possible and/or not desirable
David Pimentel’s group (8 papers, 1979 to 2002)
“Use of biomass energy as a primary fuel in the United States would be impossible
while maintaining a high standard of living”
“Large-scale biofuel production is not an alternative to the current use of oil and
is not even an advisable option to cover a significant fraction of it.”
Others
Power density of photosynthesis is too low for biofuels to have an impact on
greenhouse gas reduction (Hoffert et al., 2002)
Impractically large land requirements for biomass energy production on a scale
comparable to energy/petroleum use (Trainer, 1995; Kheshgi, 2000; Avery, 2006)
2030: Ethanol (corn and cellulose) 2.5% of transportation energy - 2% of this
cellulosic (EIA, 2006)
Any substantial increase in biomass harvesting for the purpose of energy
generation would deprive other species of their food sources and could cause
collapse of ecosystems worldwide (Huesemann, 2004)
Because of large land requirements, biofuels are not a long-term practical solution
to our need for transportation fuels (Jordan and Powell, July 2006, Washington Post)
30
Biomass resource sufficiency: The world is confused & uncertain
The math is not the problem
{
VMT
MPG • YP/F
{
NNLFP =
-I
1
P
NNLFP: Net new land, ignoring changed land for food production (acres)
VMT: Vehicle miles traveled (miles/yr)
MPG: Miles/gallon gasoline equivalent
YP/F: Process yield (gallons gasoline equivalent/ton dry biomass)
I: Feedstock produced from currently-managed lands (ton dry biomass)
P: Productivity of biomass production (tons/acre/year)
31
Productivity (tons/acre/yr)
Factors Impacting Biomass Feedstock Availability:
Feedstock Productivity (P)
30
Current
Projected
25
20
16.5
25
24
15
12.5
15
7.5
10
5
5
1.3
0
Pimentel et Current SG
Corn Miscanthus SG, 2050 Energy Crops Energy Crops Energy cane,
projected
al. (2002) (McLaughlin) Whole plant (Heaton & (McLaughlin) U.S., 10 years U.S., Mature
U.S. Ave.
Long)
(R. Hamilton)
(V. Khosla)
(Botha, Reinach)
Heaton and Long: 3 site average in Illinois over 2 years, direct comparison with switchgrass
(Cave-in-Rock), which averaged 4.6 tons/acre/yr
Richard Hamilton (Ceres) “[Available information]…strongly suggest[s] that over the next decade or so
the deployment of modern breeding technologies will result in average energy yields of at least 15 tons
per acre, and that these averages can be sustained across a broad range of geographic and environmental
conditions, including the approximately 75 million acres of crop and pasture land in the United States that
could easily be converted to their cultivation without impacting domestic food production.”
32
Land Area (Millions of Acres)
Land Area Required for Current U.S. Light Duty Mobility in
Relation to Vehicle Efficiency
Land used
for animal
feed
160
140
120
100
Without Residue Utilization
80
60
Idled by federal
programs, mid 80smid 90s
40
CRP
20
With Residue Utilization
0
1
2
3
4
Vehicle Efficiency Multiplier
High Vehicle Efficiency
A central feature of all sustainable
transportation
scenarios
5
6
Battery/EV; H2/fuel cell:
Avoids otherwise small travel radius
•LDV VMT = 2.5 trillion vehicle miles traveled
•Waste availability: 200 million dry tons
biofuelsaverage, tentative)
•Switchgrass productivity: 10 dry tonss/acre/year (20Cellulosic
to 30 year projected
•Fuel yield: 100 gallons/dry ton
Avoids otherwise large footprint
33
Doesn’t increasing biofuel production mean either producing less food or
recruiting new land into growing biomass and hence lost wildlife habitat?
Not necessarily!
Integrating Feedstock Production Into Currently-Managed Land (I)
Food production is usually assumed to remain static, or extrapolated,
in analyses of biomass supply.
Yet new demand for non-nutritive cellulosic biomass due to cost-competitive
processing technology would very likely result in large changes.
Farmers would rethink what they grow and how they grow it.
Feed protein/feedstock coproduction
Bioenergy cover crops
New crop varieties with higher fiber yields
Increase production on under-utilized land (e.g. hay, pasture)
Agricultural residue recovery, enhanced by appropriate crop rotations
Feedlot pretreatment to make calories more accessible
34
Feed Protein/Feedstock Coproduction
Concept
Switchgrass
Feed Protein
Protein Recovery/
Processing
(& Pretreatment)
Fuels/
Chemicals
Composition & productivity comparison
Protein
Mass Productivity
(Mass Fraction)
(tons/acre/year)
Switchgrass
5.0 – 10
.08 - 0.12 (early cut)
Crop
Soybeans
1.1 – 1.3
0.36 - 0.5 (bean only)
Protein Productivity
(tons/acre/year)
0.4 – 1.2
0.40 – 0.65
• Production of perennial grass could potentially produce the same amount of feed
protein per acre while producing a large amount of feedstock for energy production
• Requires readily foreseeable processing technology to recover feed protein
• Many positive indications of feed protein quality, but not fully established
• Not pursued now because of absence of demand for cellulosic residues
• Cellulosic feedstocks could also be coproduced from large biomass soybeans
35
Reimagining Agriculture to Accommodate Large Scale Energy
Production
New demand --> new rewards & opportunities --> new agriculture
New uses for existing crops
(e.g. corn stover)
New combinations of existing crops
New & improved crops &
cropping systems
This new agriculture
has received only scant
investigation worldwide
Different solutions will
be most practical in
different local situations
36
Bioenergy cover cropping in Iowa,
A. Heggenstaller, M. Liebman, R. Anex
Returning to that simple equation…
Parameter
-I
Ratio
Least
Most
Efficient Efficient (Max/Min)
VMT (trillion miles, 2050)
6.1
MPG (LDV)
21
YP/F (gallons/ton)
4.5
1
P
Source
(High, Low)
1.4
“Car Talk” scenarios
50
2.4
Current, D. Friedman
36
91
2.5
Recent NREL, RBAEF
0
600
P (tons/acre/year)
1.3
24
18
NNLFP (million acres)
5,328
14
381
I (million tons)
37
{
{
NNLFP =
VMT
MPG • YP/F
Infinite
Many, “Billion tons”
D. Pimentel, V. Khosla
Opportunities to Increase Bioenergy Feedstocks from Managed Lands
Category of Change
Illustrative Large Impacts
Primarily technological
(process yield, crop
productivity)
Anticipated improvement in process yield & energy crop
productivity together would increase per acre biofuel yield
by ~ 8-fold (1370 gal gasoline equivalent, GE, per acre)
Primarily behavioral
(diet, exports, VMT)
80 million acres currently devoted to producing export crops
has a biofuel production potential of 110 billion gal GE
Shifts in meat consumption could make available large
acreages (~50 million acres), with a corresponding biofuel
production potential on the order of 80 billion gal GE
Drive less, mass transport, “smart growth”
Both technological &
behavioral
(MPG, integration of
feedstock production
into managed land)
Multiple complimentary
changes
Bioenergy cover crops, feasible on perhaps 1/3 of agricultural
land: ~ 66 billion gal GE
1/2 soy replaced by switchgrass with constant feed protein
Production: ~48 billion gal GE
Technically-possible mileage increases could decrease fuel
demand by 2.5-fold
Becomes realistic to consider meeting all U.S. mobility demand
from biofuels, with some scenarios requiring little if any new
land to achieve this
Energy crops, 15 dt/yr (Ceres); Cover crops, 5 dt/yr (D. Bransby); 91 gal GE/dry ton (RBAEF)
38
New Land Required to Satisfy Current U.S. Mobility Demand
CRP Land
(30 MM)
U.S. Cropland
(400 MM)
Status quo
36 gal Geq/ton, current mpg, no ag. integration, 5 tons/acre*yr
Advanced
processing
91 gal Geq/ton
Vehicle efficiency 2.5X↑
Biomass yield 2.5X↑
165
65
1,030
410
LDV
HDV
Agricultural integration
I. Soy Æ switchgrass
or large biomass soy
-10
Early-cut switchgrass produces more feed protein/acre
than soy; similar benefits from “large biomass soy”
II. Corn stover (72%)
-50
Feasibility of stover utilization enhanced by rotation
Cover crops, other residues, increased productivity
of food crops, increased production on under-utilized land…
III. Other
0
39
200
400
600
800
1,000
New Land Required (million acres)
1,200
Approaches to Energy Planning & Analysis
1. Bury our heads in the sand. Pretend that energy challenges are not real or will go away.
2. Extrapolate current trends.
3. Hope for a miracle (e.g. Hoffert et al., Science, 2002).
• Acknowledge the importance of sustainable and secure energy supplies
• Dismiss foreseeable options as inadequate to provide for the world’s energy needs
• Call for “disruptive” advances in entirely new technologies whose performance
cannot be foreseen.
4. Innovate & change.
• Define sustainable futures based on mature but foreseeable technologies
in combination with an assumed willingness of society to change in ways that increase
resource utilization efficiency
• Work back from such futures to articulate transition paths beginning where we are now
#1 and #2 do not offer solutions to sustainability and security challenges.
#3 should be pursued but is too risky to rely on.
#4 is the most sensible choice if it is assumed that problems associated with
sustainability and security are important to solve.
40
Environmental “footprint”: Land area required to provide for resource
consumption & waste assimilation on a sustainable basis
Population
6 billion
6 billion
6 billion
6 billion
10 billion
1.20
12.0
1.00
10.0
8.0
Built-up
Forest
6.0
4.0
2.0
Assumed
Footprint
0.0
61
World (2003)
India
Denmark
USA
Denmark
0.60
0.40
Fishing
GrazingLand
Number
of Earths
1.366
0.4
3.2
5.2
5.1
www.footprintnetwork.org
41
0.80
Energy
Number of Earths
Billion global hectares
14.0
71
0.20
Cropland
0.00
76
81
86
91
96
Year
Wackernagel et al., PNAS (2002)
The Next Industrial Revolution?
Hawkins, Lovins, and Lovins, “Natural Capitalism”
The first industrial revolution
Context: Resources plentiful, people scarce
Response
Dramatic increases in
• Labor productivity (output/person/hour): 100-fold higher
• Fraction of energy supply from non-sustainable sources: from 0 to ~80%)
• Resource consumption per capita
• Population
• Level of services (mobility, housing, dietary variety, information) expected
The second industrial revolution
Context: Resources scarce, people plentiful
Response
Population stabilization (appears to be happening)
Dramatic increases in
• Resource productivity (service delivered/resource invested)
• Reliance on sustainable resources, especially for energy
42
Collaborators
Economic & Process Analysis - Mark Laser, Charles Wyman, Eric Larson,
Bruce Dale, RBAEF team
Resource & environmental analysis - Nathanael Greene, John Sheehan,
Rob Anex, Tom Richard, RBAEF team, Reimagining Agriculture Team
Cellulolytic yeasts - Emile van Zyl, Riaan Den Haan, John McBride
Metabolic engineering of T. saccharolyticum & thermophilic SSF - Joe Shaw
Kara Podkaminer
Ecology of microbial cellulose utilization - Gideon Wolfaardt, Paul Weimer,
Javier Izquierdo
Physiology of microbial cellulose utilization - Percival Zhang, Yanpin Lu,
Nicolai Panikov
Science of biomass recalcitrance - Bioenergy Science Center team
Technology development & commercialization - Mascoma Corp. team
43