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Life cycle assessment: Concepts & use
Rich Helling The Dow Chemical Company Sustainable Chemistry 5 December 2017
Decisions are multi-attribute, complex & subjective
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$ Energy
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Life cycle assessment (LCA) provides environmental insights for decisions
Product life cycles
Know the inputs & outputs!
Ener
gy &
mat
eria
ls Em
issions & wastes
Calculate potential impacts
Σ Flow × Characterization Factor all stages all species
Potential Environmental Impact
=
Ene
rgy
& m
ater
ials
Em
issions & w
astes
*as defined by the international LCA standard ISO 14044
Key LCA concept: the functional unit
Functional Unit: The quantified performance of a product system, so that one can make valid comparisons of them.
Can of paint: not a
functional unit
Cover 1 m2 interior surface for 50 years;
a functional unit
LCA cannot tell if something is “green” or “sustainable”, only how A compares to B
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GHGs ENERGY ACID GAS
NUTRIENTS LAND WATER
Option A
Option B
Option A
Option B
Option A
Option B Option A
Option B
Option A
Option B
Option A
Option B
Simple carbon footprint example
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Raw material
extraction Refining Use End of
Life
2 kg CO2 5 kg CO2 1 kg CH4 10 kg CO2
Stage Emissions Characteri
zation Factor (CF)
Emissions x CF = GWP
Raw Matl’s 2 kg CO2 1 2
Refining 5 kg CO2 1 5
Manu-facturing 1 kg CH4 25 25
0.01 kg N2O 298 3
EOL 10 1 10
TOTAL life cycle GHG emissions (GWP) 45 kg CO2-eq
Characterization Factors (Global
Warming Potential)
GHG GWP
(kg CO2-eq/kg GHG)
CO2 1
CH4 25
N2O 298
0.01 kg N2O
ISO standards define process and expectations for comparative LCA claims
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ISO
ISO process reflects good project management
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ISO
In practice, start simple & iterate as needed
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Comparative Assertions
Information about our products
Internal decisions
Life cycle thinking & discussion
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Example: Polyurethane-Based Shoe Soles
Ref: Shawn Hunter, Rich Helling, Andrea Benvenuti, Renato Paludetto, Giuseppe Lista “The Green Footprint Project: Improving LCA in by Careful Bio-Feedstock Selection ” SusPolyUrethane 2013, 8 May 2013, Amsterdam
Many roads to shoe soles…
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Adipic acid
Azelaic acid
Why might bio-based materials have sustainability advantages?
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Σ add it up
Atmospheric CO2 incorporated into
product
But, GHGs also emitted throughout life
cycle
How does the total compare to fossil PU?
GHG advantage is not guaranteed – must conduct the LCA!
PU Shoe Sole LCA
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Goal: To assess the life cycle impacts of polyurethane shoe soles made from fossil-based and renewable-based polyesters
PU production
Polyester production
Adipic Acid production
Fossil feedstock
PU production
Polyester production
Azelaic Acid production
Bio-based feedstock
1 kg bio-based PU
?
1 kg fossil-based PU
Life Cycle Impact Assessment = sum of all potential impacts across the life cycle
Functional Unit: 1 kg of polyurethane foam
Significant GHG Advantage for PU from tallow (waste)
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Tallow-based PU is advantaged in all categories except water
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Sensitivity Analyses on the bio-feedstock options
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Waste fat for tallow is not a waste (has burdens)
Use of vegetable oil in place of tallow
EIO-LCA
Results depend on choice of feedstock & burdens
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Impact Category Fossil-based Tallow-based Tallow-based (with burdens)
Vegetable oil-based
Global Warming
Fossil Energy
Acidification
Eutrophication
Ozone Depletion
Smog Creation
Land Use
Water Use
highest impact potential
lowest impact potential
somewhere in the middle
Hefty® EnergyBagTM LCA
Ref: Han Zhang, Rich Helling, Jill Martin ” Scoping Life Cycle Assessment of Hefty® EnergyBagTM Program: An Innovative Plastic Waste Management System ” ACLCA XVII, Portsmouth, NH, October 4, 2017 ® ™ Hefty and EnergyBag are trademarks of Reynolds Consumer Products, LLC
®™Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow
Flexible Plastic Packaging (FPP): Recycling Challenges
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Infrastructure Collection and Sortation
Technical Use of multiple materials
makes FPP difficult to recycle
Consumer Behavior Consumers want to do the right thing but are confused
End Markets Limited currently
Consumers receive Hefty® EnergyBagTM
When bag is full, put it in regular recycle bin/cart
Bags and other recyclables are picked up by local haulers
Bags are sent to and sorted at the local Material Recovery
Facility (MRF)
Sorted bags can be sent to energy recovery facilities, such as pyrolysis and cement kiln
Use energy to run plant and produce cement or to produce
new fuel or plastics
Hefty® EnergyBagTM Process
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M R F
Functional Unit The output of the system is to produce products (diesel, naphtha, fuel gas or cement) and manage non-recycled plastic (NRP) waste (feedstock for chemical recycling vs. landfill)
Therefore, the functional unit for today’s presentation is:
Produce 1kg of diesel and manage 1.11kg of NRP (cradle to gate)
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System Boundary, Diesel Case
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EnergyBag production
LLDPE
Extrusion
Pallet
Cardboard box
EnergyBag shipping
Curbside collection
MRF processing
Transport from MRF
to end user Pyrolysis Diesel
Convention diesel
production Diesel
Curbside collection
MRF processing
Transport from MRF to landfill
Landfill
Naphtha Fuel gas Char
Transport
Landfill
Diesel truck
operation
Diesel truck
operation
Bag distribution
Benchmark processes
Non-recycled plastic
Pyrolysis usually largest contributor
27 Method: TRACI 2.1 V1.01 / US 2008; Cumulative Energy Demand V1.08
Potential environmental impacts to produce 1kg diesel and manage 1.11kg of NRP
Hefty® EnergyBagTM diesel has lower potential impacts vs. conventional system
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Environmental impact to produce 1kg diesel and manage 1.11kg of NRP
Sensitivity Analysis – impact of distance from MRF on LCA metrics
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Use of nitrapyrin on US corn
Ref: Helling, Rich and Brian Wendelburg “Uncertainty & sensitivity in LCA: Use of nitrapyrin to reduce greenhouse gas emissions from US corn production” ACLCA XVII, Portsmouth, NH, October (2017)
Nitrification inhibitor
•Reduce N losses
•Improve N uptake by plants
•A meta-analysis of field studies give statistical measurements of benefits: • Lower greenhouse gas emission • Lower leaching of N • Improved yields
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Simple process map
Produce TG Produce
formulation
Ship to Iowa
Package in Iowa
Apply to field
Use phase emissions
End of life
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Corn farming models
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Kim, et al., IJLCA
Michigan State University
ecoinvent Agri-footprint
by
Blonk Consultants
Corn in Iowa – use of Instinct HL shows clear GWP advantage & some marine eutrophication
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Sensitivity analysis: Climate change benefit using different corn farming models
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kg CO2eq/kg w/o
kg CO2eq/kg with
Decrease, CO2eq/kg
Decrease, %
Kim, et al. 0.27 0.18 0.086 32%
Agri-footprint
0.51 0.42 0.096 19%
ecoinvent 0.64 0.56 0.070 11%
Uncertainty – climate change and eutrophication results are robust to uncertain model inputs
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Conclusions
Summary
• LCA is usefull to find & improve hotspots and make comparisons
• LCA does not determine greeness or sustainability • Always start simple and add complexity & detail as needed! • Polyurethane example: feedstock choices – both physical and
attribution – matter! • EnergyBag example: a two-part functional unit can be a useful
basis for waste-based processes • Nitrapyrin example: importance of sensitivity and uncertainty
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Questions?
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Acknowledgements
The “Green Footprint Project” was part of the EU “LIFE+” program:
LIFE07 ENV/IT/000412
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References • Helling, Rich “Life cycle assessment: Concepts & use” Michigan DEQ Sustainability Series Webinar,
22 June 2017 https://attendee.gotowebinar.com/recording/2505699422317413889 • Han Zhang, Rich Helling, Jill Martin ” Scoping Life Cycle Assessment of Hefty® EnergyBagTM
Program: An Innovative Plastic Waste Management System ” ACLCA XVII, Portsmouth, NH, October 4, 2017
• Shawn Hunter, Rich Helling, Andrea Benvenuti, Renato Paludetto, Giuseppe Lista “The Green Footprint Project: Improving LCA in by Careful Bio-Feedstock Selection ” SusPolyUrethane 2013, 8 May 2013, Amsterdam.
• Helling, Richard, Renato Paludetto, Andrea Benvenuti, and Giuseppe Lista “Life Cycle Assessment of polyurethanes for shoe soles with at least 20% renewable (bio-based) content: the Green Footprint Project” ISO 14044 Public Report, The Dow Chemical Company, August (2011)
• Pahola Thathiana Benavides, Pingping Sun, Jeongwoo Han, Jennifer B. Dunn, Michael Wang “Life-cycle analysis of fuels from post-use non-recycled plastics” Fuel 203 (2017) 11–22 http://dx.doi.org/10.1016/j.fuel.2017.04.070
• Helling, Rich and Brian Wendelburg “Uncertainty & sensitivity in LCA: Use of nitrapyrin to reduce greenhouse gas emissions from US corn production” ACLCA XVII, Portsmouth, NH, October (2017)
• Wolt, Jeffrey D., “A meta-evaluation of nitrapyrin agronomic and environmental effectiveness with emphasis on corn production in the Midwestern USA” Nutrient Cycling in Agroecosystems, vol. 69, pp 23-41 2004
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