To reduce the environmental impacts of the aviation sector as air traffic grows steadily, the aviation industry has paid increasing attention to bio-based alternative jet fuels (AJFs), which may provide lower life-cycle petroleum consumption and greenhouse gas (GHG) emissions than petroleum jet fuel. This study presents well-to-wake (WTWa) results for four emerging AJFs: ethanol-to-jet (ETJ) from corn and corn stover, and sugar-to-jet (STJ) from corn stover via both biological and catalytic conversion. Three H2 options for STJ via catalytic conversion are investigated: external H2 from natural gas (NG) steam methane reforming (SMR), In-situ H2 and H2 from biomass gasification. Results demonstrate that the feedstock is a key factor in the WTWa GHG emissions of ETJ: corn- and corn stover-based ETJ are estimated to produce WTWa GHG emissions that are 16% and 73%, respectively, less than those of petroleum jet. As for the STJ pathways, this study shows that STJ via biological conversion could generate WTWa GHG emissions 59% below those of petroleum jet. STJ via catalytic conversion could reduce the WTWa GHG emissions by 28% with H2 from NG SMR or 71% with H2 from biomass gasification than those of petroleum jet. Corn- and corn stover-based ETJ as well as corn-stover-based STJ show potentials to reduce WTWa GHG emissions compared to petroleum jet. On the other hand, ETJ offers unique opportunities to exploit extensive existing corn ethanol plants and infrastructure, and to provide a boost to staggering ethanol demand, which is largely being used as gasoline blendstock.

1. WELL-TO-WAKE ANALYSIS OF ETHANOL-TO-JET
AND SUGAR-TO-JET PATHWAYS
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JEONGWOO HAN
Argonne National Laboratory
July 11 – 12, 2017
Arlington, VA
BIOECONOMY 2017
DOMESTIC RESOURCES FOR A VIBRANT FUTURE

2. Introduction
 Solutions for sustainable growth of aviation traffic
– Fuel consumption reduction: More efficient aircraft, shorter routing, and optimized
management and planning
– Greenhouse Gas (GHG) emissions reduction: Low-carbon bio-based jet fuels, such as
hydroprocessed renewable jet (HRJ), biomass-based Fischer-Tropsch jet (FTJ), Sugar-
To-Jet (STJ), Alcohol-To-Jet (ATJ), etc.
 Most Well-to-Wake (WTWa) analyses are focused on HRJ and FTJ
GHG
3.0 Trillion MJ[1]
4.9 Trillion MJ[1]
U.S. Aviation Sector
Year 2015 Year 2050
161 million tonne CO2e[2] Global jet fuel consumption in 2012: 11.2 Trillion MJ[3]
[1] U.S. EIA. Annual Energy Outlook 2017.
[2] U.S. EPA. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2015.
[3] U.S. EIA. International Energy Statistics

3. Sustainable Growth of Aviation Traffic
❶
❷
❸
2005 2010 2020 2030 2040 2050
Biofuels
-50% by 2050
GHGEmissions
C Neutral Growth
❶ Improve fleet fuel efficiency by 1.5% per year from now until 2020
❷ Cap net emissions from 2020 through carbon neutral growth
❸ by 2050, net aviation carbon emissions will be half of what they were in 2005.

4. System Boundary of Ethanol-To-Jet (ETJ) and
Sugar-To-Jet (STJ) Pathways
4
[4] Wang et al. 2016. NREL/TP-5100-66291.
[5] Davis et al. 2013. NREL/TP-5100-60223.
[6] Davis et al. 2015. NREL/TP-5100-62498.
Key Issues:
1. H2 sources for STJ via catalytic conversion
2. Co-product handling methods

5. Key Inputs of Ethanol-To-Jet (ETJ) and Sugar-To-
Jet (STJ) Pathways
5
Feedstock Corn Corn Stover
Conversion ETJ ETJ
Biological
STJ
Catalytic STJ
Ext. H2 In-Situ H2 Gasi. H2
Jet yield (MJ jet/kg feedstock) 6.78 4.71 4.42 8.39 4.85 5.6
Natural gas use (kJ/MJ jet) 439 - - - - -
Hydrogen use (kJ/MJ jet) 81.3 80.9 123 528 - -
Electricity use (Wh/MJ jet) 27.3 - - - 1.81 -
Gasoline yield (kJ/MJ jet) 210 212 - - - -
Diesel yield (kJ/MJ jet) 113 115 - - - -
DGS yield (dry g/MJ jet) 57 - - - - -
Electricity yield (Wh/MJ jet) - 32 22.3 12.6 - 2.8

6. ETJ with Corn ETJ with Stover STJ with Stover
Corn stover-based ETJ can reduce WTWa GHG
emissions by 73% relative to petroleum jet
 Key WTWa GHG emissions sources:
– Corn-based ETJ: Corn farming, ethanol production and land use change (LUC)
– STJ via catalytic conversion: H2 from NG steam methane reforming (SMR)
6
Based on
 Han et al. 2017 Biotechnology
for Biofuels

7. Trade-off between GHG emissions and petroleum
savings exists for STJ via catalytic conversion
• For STJ produced via catalytic conversion, a trade-off exist between GHG
emissions and petroleum savings by different H2 sources.
• For the other pathways, GHG emissions and petroleum savings are
directionally correlated. 7
Per-tonne results can show the
resource utilization impacts clearly

8. Conclusions
• WTWa GHG emissions reductions relative to
petroleum jet
 Corn-based ETJ: 9 – 16%
 Stover-based ETJ: 68 – 73 %
 Stover-based STJ (Biological): 59%
 Stover-based STJ (Catalytic): 28 – 71%
• H2 source for stover-based STJ (catalytic) is
critical.
• ETJ offers unique opportunities to exploit
extensive existing corn ethanol plants and
infrastructure.
8

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10. Well-To-Wake Analysis of Ethanol-To-Jet and Sugar-To-Jet Pathways
Bioeconomy 2017: Domestic Resources for a Vibrant Future Jeongwoo Han
Argonne National Laboratory
9700 S. Cass Avenue | Argonne, IL 60439
Visit www.greet.es.anl.gov
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Background
GHG
3.0 Trillion MJ
4.9 Trillion MJ
U.S. Aviation Sector
Year 2015
Year 2050
161 million tonne CO2e
Global jet consumption in 2013:
11.2 Trillion MJ
• Solutions for sustainable growth of
aviation traffic
 More efficient aircraft, shorter routing, and
optimized management and planning
 Low-carbon bio-based jet fuels, such as
hydroprocessed renewable jet (HRJ),
biomass-based Fischer-Tropsch jet (FTJ),
Sugar-To-Jet (STJ), Alcohol-To-Jet (ATJ), etc.
• Need to evaluate environmental
sustainability of alternative jet fuels
 Most well-to-wake (WTWa) analyses are
focused on HRJ and FTJ
 Emerging technologies (e.g., ETJ and STJ)
have yet to be evaluated
• Steady growth in jet fuel
demand
❶ Improve fleet fuel efficiency by 1.5% per year from now until 2020
❷ Cap net emissions from 2020 through carbon neutral growth
❸ by 2050, net aviation carbon emissions will be half of what they
were in 2005.
❶
❷
❸
2005 2010 2020 2030 2040 2050
Biofuels
-50% by 2050
GHGEmissions
C Neutral Growth
Well-to-wake GHG emissions results
Major GHG
emissions sources
 Corn-based ETJ:
Farming + LUC
 STJ w/ Catalytic:
H2
ETJ with Corn ETJ with Stover STJ with Stover
Feedstock Corn Corn Stover
Conversion ETJ ETJ
Biological
STJ
Catalytic STJ
Ext. H2 In-Situ H2 Gasi. H2
Jet yield (MJ jet/kg feedstock) 6.78 4.71 4.42 8.39 4.85 5.6
Natural gas use (kJ/MJ jet) 439 - - - - -
Hydrogen use (kJ/MJ jet) 81.3 80.9 123 528 - -
Electricity use (Wh/MJ jet) 27.3 - - - 1.81 -
Gasoline yield (kJ/MJ jet) 210 212 - - - -
Diesel yield (kJ/MJ jet) 113 115 - - - -
DGS yield (dry g/MJ jet) 57 - - - - -
Electricity yield (Wh/MJ jet) - 32 22.3 12.6 - 2.8
System boundaries and key inputs/outputs
• WTWa GHG emissions reductions relative to petroleum jet
 Corn-based ETJ: 9 – 16%
 Stover-based ETJ: 68 – 73 %
 Stover-based STJ (Biological): 59%
 Stover-based STJ (Catalytic): 28 – 71%
• H2 source for stover-based STJ (catalytic) is critical.
• ETJ offers unique opportunities to exploit extensive
existing corn ethanol plants and infrastructure.
• U.S. EIA. Annual Energy Outlook 2017.
• U.S. EPA. Inventory of U.S. Greenhouse Gas Emissions
and Sinks: 1990-2015.
• U.S. EIA. International Energy Statistics
• UNFCCC Climate Talks, The right flight path to reduce
aviation emissions
• Davis et al. (2013) NREL/TP-5100-60223.
• Davis et al. (2015) NREL/TP-5100-62498.
• Han et al. (2017) Biotechnology for Biofuels.
• For STJ produced via catalytic conversion, a trade-off exist
between GHG emissions and petroleum savings by
different H2 sources.
• For the other pathways, GHG emissions and petroleum
savings are directionally correlated.
Stover resource utilization
Conclusions
References