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Life-cycle Analysis with the
GREET Model
Michael Wang
Systems Assessment Center
Energy Systems Division
Argonne National Laboratory
Presentation at the SwRI LCA Symposium
Nov 3, 2021
greet.es.anl.gov
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Transportation accounts for 33% of US total GHGs; GREET includes all transportation subsectors
Road (72%*) Air (11%*)
Rail (2%*) Marine (3%*)
GREET
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• Light-duty vehicles
• Medium-duty vehicles
• Heavy-duty vehicles
• Various powertrains:
Internal combustion
Battery electric
Fuel cells
Freight transportation
GREET includes
• Diesel
• Electricity
• CNG/LNG
The sector is under pressure to
reduce air emissions and GHG
emissions. GREET includes
• Ocean and inland water
transportation
• Baseline diesel and alternative
marine fuels
Globally, a fast growing sector
with GHG reduction pressure.
GREET includes
• Passenger and freight
transportation of various
alternative fuels blended with
petroleum jet fuels
* Share of US transportation GHG emissions; remaining 12% is from pipelines and offroad.
GREET now also cover the building sector LCA.
GREET covers many groups of energy systems
Petroleum Sector:• Conventional oil
• Shale oil
• Oil Sands
Natural Gas Sector:• Conventional NG
• Shale gas
Gasoline
Diesel
Jet fuel
Liquefied petroleum gas
Naphtha
Residual oil
1st Gen Feedstocks:
• Corn
• Sorghum
• Soybeans
• Rapeseeds
• Sugarcane
• Palm
2nd Gen Feedstocks:
• Dedi. energy crops
• Crop residues
• Forest residues
• MSW
• Animal wastes
Algae
Natural gas
Coal
Residual oil
Biomass
Nuclear
Hydro
Wind
Solar
Electric Systems:• Electricity generation at
US plant level
• Aggregate to national,
NERC, and state level
• With CCS, if applicable
Natural gas
Biomass
Coal
Petroleum coke
Coke oven gas
Electrolysis with electricity
Nuclear energy
Hydrogen Economy:• Gaseous hydrogen
• Liquid hydrogen
• With CCS, if applicable
• NG end use in electric,
industrial, and residential
sectors
• Transportation sector:
CNG, LNG
• Alternative fuels: LPG,
methanol, DME, FT
diesel, FT jet
Renewable
Energy/Fuels:• Ethanol
• Biodiesel
• Renewable diesel
• Renewable gasoline
• Renewable jet fuel
• Renewable natural gas
Renewable Hydrogen via
electrolysis:• Wind
• Solar
• Nuclear
CO2 Sources• Ethanol plants
• NG SMR plants
• Cement plants
• Etc.
Electro-Fuels• Gasoline
• Diesel
• Jet fuel
• Methanol
4Besides energy systems, GREET also includes
plastics and products.
Life cycle of petroleum fuels
▪GREET covers from petroleum recovery to fuel use (combustion) by including all energy
inputs and emissions for each stage.
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Exploration
and recovery
Transportation
of crude
Petroleum
refining
Fuel
transportation
and distribution
Fuel
combustion
Energy sources
Coal Natural gas Oil RenewablesEmissions
Crude oil
Co-reactants,
Catalysts,
Methanol,
Corn-derived ethanol
Well-To-Wheels (WTW)
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GREET system boundary for biofuel LCA: direct activities and indirect effects are included
Key factors determining biofuel LCA
results❑ LCA system boundary
❑ Feedstock types
❑ Conversion technologies: energy balance
and materials inputs such as enzyme and
catalyst
❑ Technology improvement over time
❑ Biorefineries with distinctly different
products: co-product methods
❑ Direct and indirect land use changes
Approach to developing a materials inventory (bill of materials) for vehicles in GREET 2
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Vehicle ModelVehicle fuel economy
Vehicle and component weights
ASCM1 Dismantling
Reports
Other literatureEngineering
Calculations
Vehicle Components
• Body
• Powertrain
• Transmission
• Chassis
• Electric traction motor
• Generator
• Electronic controller
Battery
• Startup (Pb-Acid)
• Electric-drive
• Ni-MH
• Li-ion
Fluids
• Engine oil
• Power steering fluid
• Brake fluid
• Transmission fluid
• Powertrain coolant
• Windshield fluid
• Adhesives
1. Automotive System Cost Model, IBIS Associates and Oak Ridge National Laboratory
GREET relies on a variety of data sources
Baseline technologies and systems
• Energy Information Administration’s data and its Annual Energy Outlook projections
• EPA eGrid for electric systems
• US Geology Services for water data
Field operation data
• Oil sands and shale oil operations
• Ethanol plants energy use
• Farming data from USDA
Simulations with models
• ASPEN Plus for fuel production
• ANL Autonomie for fuel economy
• EPA MOVES for vehicle emissions, EPA AMPD for stationary emissions
• LP models for petroleum refinery operations
• Electric utility dispatch models for marginal electricity analysis
Collaboration with other organizations
Industry inputs
• Fuel producers and technology developers on fuels
• Automakers and system components producers on vehicles
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GREET results inform various DOE offices and programs
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(DOE EERE Record 21003, Sept. 2021)
▪ Life-cycle GHG emissions of a small SUV
▪ Generated with GREET2020
▪ Combination of powertrain and fuel
technologies for deep decarbonization by
2050
GHG emissions of vehicle manufacturing cycle for a small SUV
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(DOE EERE Record 21003, Sept. 2021)
Comparative life-cycle GHG emissions of a mid-size global average car by powertrain, 2018 (tonnes per vehicle lifetime)
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Source: IEA (2019), "Global EV Outlook 2019", IEA, Paris
ICE HEV PHEV BEV FCEV 0
5
10
15
20
25
30
35
40
45
t CO2-eq Effect of larger
battery (+ 200 km)
Tank-to-wheel fuel
cycle
Well-to-tank fuel
cycle
Vehicle cycle -
batteries (200 km)
Vehicle cycle -
assembly, disposal
and recycling
Vehicle cycle -
components and
fluids
Variability relative
to vehicle size
GREET life-cycle GHG emissions of ethanol: feedstock is the main driver
12
9552
328
11-4
-150
-100
-50
0
50
100
150
With LUC Without LUC With LUC With LUC With LUC
Gasoline Corn ethanol Sugarcaneethanol
Corn stoverethanol
Switchgrassethanol
Miscanthusethanol
WT
W G
HG
em
issio
ns,
g C
O2e/M
JWTP Biogenic CO₂ in Fuel PTW LUC WTW
Carbon intensity of corn ethanol without LUC
▪ Corn ethanol CIs have
decreased over the last 15
years (23% or 14gCO2e/MJ)
▪ Corn ethanol CI (including
LUC) in 2019 shows 44%
reduction compared to fossil
baseline (93 gCO2e/MJ)
▪ Ethanol production-related
emissions have decreased
30% (11 gCO2e/MJ; 36→25)
▪ Corn farming shows
reductions in GHG, 15% (5
gCO2e/MJ; 33→28)
5856
5553 53
51 51 5149 47 46 45 46
44 45
-20
-10
0
10
20
30
40
50
60
70
80
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
Co
rn e
tha
no
l c
arb
on
in
ten
sity
with
ou
t LU
C (
gC
O2e
/MJ)
Corn farming energy Fertilizers and chemicals Displacement credit Ethanol production
Transportation Combustion Total CI
13
A recent application of GREET LCA for EVs in global GHG regulations
15
Observations: Values and Limitations of LCA❑ LCA is a major step to holistically evaluate sustainability of a technology
▪ From singular stages to the complete supply chain so that shift in environmental burdens from one stage to the other is not missed
▪ LCA thinking has helped changes in corporation and consumer behaviors▪ LCA based regulations have helped promotion of sustainable technologies▪ Process level details along a technology’s supply chain provide insights of opportunities and challenges of a
technology’s sustainability
❑ LCA results are still subject to variations and uncertainties▪ LCA system boundary depends on scope of LCA▪ Attributional and consequential LCA address different questions and have completely different boundaries▪ Co-product methods in LCA can be subjective and affect LCA results significantly▪ Data availability and representation
✓ Temporal variation✓Geographic/spatial variation✓Data uncertainty (e.g., sources of process energy/chemicals, methane emissions, land use changes from
biofuels)▪ Limitations of comparative results from LCA
✓ Current vs. uncertain future✓Different technology readiness levels (TRLs) across processes and pathways✓ Resource and infrastructure availability✓ Economics, production scalability, and market acceptance/competitiveness
