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TRANSCRIPT
Biofuels and Carbon: Implications for
Powertrain Strategies
John M. DeCiccoUniversity of Michigan Energy Institute
UMTRI Automotive Futures Conference on Powertrain Strategies for the 21st Century
July 22, 2015
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Particular Agricultural
InterestsEnergy Security
Concerns
CO2
Emissions Reduction
Support for Biofuels
Renewable Fuel Standard (RFS)• Legislation 2005 EPAct: RFS1, 7.5 Ggal (billion gallons) by 2012 2007 EISA: RFS2, ramp up to 36 Ggal by 2022, along
with lifecycle GHG targets for categories of fuel
• As in California’s Low-Carbon Fuel Standard (LCFS), an unprecedented requirement to use lifecycle analysis (LCA) for regulation
• Most recent EPA RFS proposed rule 15.9, 16.3, 17.4 Ggal in 2014, 2015, 2016, versus
~18, 20, 22 Ggal, respectively, as called for by EISA Cellulosic biofuel: 33 Mgal, versus 1.75 Ggal in 2014
as called for by EISA
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U.S. biofuel consumption
0
5
10
15
2000 2005 2010 2015
Billi
on G
allo
ns p
er Y
ear
Source: EIA Monthly Energy Review, Tables 3.7, 10.3, 10.4
Ethanol
Biodiesel
For reference, total U.S. liquid motor fuel (gasoline + diesel) consumption was 180 billion gallons per year as of 2014.
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Re-examining the environmental rationale for biofuels
• A growing number of questions are being raised about real-world impacts
• Back to basics: Biofuels and Carbon 101
• What went wrong when developing the prevailing public policy view?
• Policy and strategy implications
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6
Biofuels are carbon neutral
Source: http://www.ethanolrfa.org/pages/ethanol-facts-environment
The biosphere is already recycling carbon to and from the atmosphere
P = net flow of CO2 from atmosphere into biosphere through photosynthesis (Net Primary Production, NPP)
R = return flow of CO2 from biosphere into atmosphere (Heterotrophic Respiration, Rh) from metabolism by organisms other than primary producers (such as plants, algae, etc.)
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Fuel-related CO2
emissions in the context of the carbon cycle
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Implication: for biofuels to reduce CO2
emissions, feedstock production must meet a necessary condition of:
d(NEP)/dt > 0
i.e., growth and harvest of their feedstock must increase the net rate at which CO2 is removed from the atmosphere.
Schematic for carbon balance analysis of a vehicle-fuel system
End-use CO2emissions
Processemissions
Carbon uptake
System BoundarySoil carbon
Harvest
Carbon imported from fossil resources
MotorFuelProcessing
of feedstocks into products
Carbon exported to feed and food system
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Motor Vehicles
Key carbon flows across system boundary
Fuel ProcessingCropland
Export for Food / Feed
Export in Coproducts
Net CO2Uptake
End-use CO2Emissions
System Boundary
Fossil Resource
Biogenic Process CO2 Emissions
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Carbon balance analysis
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• Examine CO2 flows (both emissions and uptake) when and where they occur Biofuel use per se does not appreciably change
tailpipe CO2 emissions Processing emissions are at least as great for
biofuels as they are for fossil fuels Any potential benefit must come from an increase in
the rate of net CO2 uptake
• Bottom line: No commercial-scale biofuel production meets the
threshold test for a CO2 reduction benefit Production efficiency gains do not change this result
Source: DeCicco, J.M. 2013. Biofuel's carbon balance: doubts, certainties and implications. Climatic Change 121(4): 801-814. dx.doi.org/10.1007/s10584-013-0927-9
Direct GHG emissions impact of using corn ethanol instead of gasoline
+4% +55% +8% +69%
Source: Direct Carbon Balance Accounting for Biofuel Production: Methodology and Case Study, University of Michigan Energy Institute (forthcoming August 2015). 12
What went wrong? • Politically, the strength of one leg of support
(certain agricultural interests) trumped careful analysis of energy and environmental rationales for renewable fuels No one bothered to validate the LCA models used to
justify biofuels’ presumed CO2 benefits The problem is LCA model structure and application
(not just disagreements over data) Argonne's GREET model gives misleading results for
transportation fuels policy
• Congress gave EPA an intractable task California’s LCFS is also deeply flawed
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GREET Model for Fuel Lifecycle Analysis
WHERE IS THE LAND?
Source: Wang, M.Q. 2005. Updated energy and greenhouse gas emissions results for fuel ethanol. 14
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A need to rethink fuel strategies• Lifecycle analysis (LCA) is scientifically incorrect
Not grounded in biogeochemical basics of the carbon cycle Static accounting cannot be used for a dynamic system;
liquid fuels require dynamic stock-and-flow analysis Prior land use (not just land-use change) always matters, but
as practiced to date, LCA misspecifies the baseline
• For transportation fuels, GHG mitigation requires Increasing the rate of net CO2 removal upstream;
substituting fuels downstream has no benefit Replacing fossil carbon with biogenic carbon is not a sufficient
condition for reducing the net CO2 flow to atmosphere
• Implications for vehicle-fuel systems planning Biofuel production likely to stagnate (RFS slowdown/rollback?) Long-term business case for biofuels will erode as policy and
investment strategies face up to scientific and market realities
Toward a better analytic paradigm
Three-Legged Stool Binary Tree
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Clarifying the “Liquid Carbon Challenge”
Reduce the demand for fuel Limit growth of travel demand (control VMT) Reduce vehicle energy intensity (improve MPG)
Reduce GHG impact of the fuel system
Capture carbon onboard vehicles (not feasible)
Use chemically carbon-free fuels (electricity, hydrogen) to shift emissions, and thereby the control problem, somewhere else
Balance CO2 emitted by vehicle with CO2 removal somewhere else• Increase net CO2 uptake in biosphere (raise NEP)
• Avoid CO2 releases that would otherwise occur
• Sequester additional CO2 in the geosphere
Transport sector CO2 mitigation options break down as:
The baseline always
matters!
Source: DeCicco, J.M. 2015. The liquid carbon challenge: evolving views on transportation fuels and climate. WIREs Energy Environ 4(1): 98-114. doi:10.1002/wene.133
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Conclusions• For several decades now, numerous federal and state
policies have sought to catalyze a viable market for alternative transportation fuels Do such efforts rest on sound public policy premises?
• Is replacing petroleum a legitimate policy goal, • or is policy better focused on reducing its associated risks
(which are largely scale related)?
For advanced biofuels in particular, after more than 30 years of R&D and greatly increased public and private investments over the past decade, how credible is the vision?
• Regarding fuels and climate policy: Downstream substitution of liquid fuels provides no climate
mitigation benefit and is therefore a misplaced priority.
As the number of interests that take climate risk seriously grows, support for biofuels will inexorably erode.