life cycle assessment: laying the foundation for a transparent supply chain shopping bag case study...
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Life Cycle Assessment: Laying the Foundation for a Transparent Supply Chain
Shopping Bag Case Study
September 26, 2013
Dr. Anahita WilliamsonDirector
Kate WinnebeckLCACP, Senior EHS Specialist
New York State Pollution Prevention Institute at RIT
Life Cycle Assessment (LCA) is a technique used to quantify the environmental impact of a product from raw material acquisition through
end of life disposition (cradle-to-grave)
Life Cycle Assessment
Remanufacture
Recycle
Reuse
Waste Treatment
LCA Methodology• A Life Cycle Assessment is carried out in four distinct
phases: (ISO 14040, 14044)
– Step 1: Goal definition and scoping. Identify the LCA's purpose, the products of the study, and determine the boundaries. (what is and is not included in the study)
– Step 2: Life-cycle inventory. Quantify the energy and raw material inputs and environmental releases associated with each life cycle phase.
– Step 3: Impact analysis. Assess the impacts on human health and the environment.
– Step 4: Report results. Evaluate opportunities to reduce energy, material inputs, or environmental impacts at each stage of the product life-cycle.
Step 1: Goal Definition and Scoping
Define the goal:– Intended application of the study– Intended audience
Define the scope: – Identify the product system to be studied– Define the functional unit– Define the boundaries of the product system– Identify assumptions and limitations of the study– Select impact categories to be included
Today’s Example
• You own a grocery store and customers are starting to request that you sell reusable shopping bags. You are curious which type of bag has the lowest environmental impact. In order to quantify and compare the bag options, a streamlined LCA is performed.
• Goal: – Determine which grocery bag – single use paper,
single use plastic, reusable plastic, or reusable cotton – has the lowest environmental impact
Sustainability Victoria, Comparison of existing life cycle analysis of shopping bag alternatives, Apr07 .
Draw the System Boundaries
• Assumptions:– All bags are manufactured 100km from the customer– All bags travel 10km from the customer to the end of life– Half of paper bags are recycled at end of life, half go to landfill– Plastic & cotton bags go to landfill at end of life
1. As a group, draw the boundaries or process flow of the system
System Boundaries
50/50 to Landfill & Recycling
Cutting down trees
Paper bag
Transform trees into
paper
Form paper into bags
Packaging & Distribution
Use
Extracting petroleum
Single use & reusable plastic bag
Transform petroleum into plastic
Form plastic into bags
Packaging & Distribution
Use Landfill
Functional Unit
• The functional unit is a measure of the function of the studied system
– Provides a reference to which the inputs and outputs can be related
– Enables comparison of two essentially different systems
• Examples– The functional unit for a paint system may be defined as the unit
surface protected for 10 years– The functional unit for a printer may be defined as the number of
printed pages of an acceptable print quality – The functional unit for power generation systems may be defined
as 1kWh of electricity
The amount of shopping bags consumed by a household to carry 70 grocery items home from the supermarket each week for 52 weeks
Bag Type Single use plastic
Single use paper
Reusable plastic
Reusable cotton
Material HDPE Unbleached Kraft paper
Polypropylene Cotton
Mass per bag 7g 42.6g 95g 85g
Relative Capacity 1 0.9 1.1 1.1
Bags per Year 520 578 4.55 4.55
Mass bags per year
3640g 24622.8g 432.25g 386.75g
Functional Unit
Step 2: Life Cycle Inventory
• Highly data intensive
• Detailed mass & energy balances performed over life-cycle
• Advantages: measure data & define baseline metrics of life-cycle processes
• Challenges: Assumptions made when data unavailable
Outputs
Products
Air, Water and Solid Emissions
Inputs
Energy
Raw Materials
database
Inventory collected from multiple sources
Step 2: Life Cycle Inventory
Toner Life-cycle Inventory
Ref: A.Ahmadi,et.al, J.Clean.Prod., 2003
Ref: A.Ahmadi,et.al, J.Clean.Prod., 2003
Toner Life-cycle Inventory
Impact Assessment Results• Impact assessment converts the inventory into impact categories or
end points which details the human health and environmental effects.
High Density Polyethylene InventoryPeer reviewed datasets imbedded in softwareData has been collected by others and represents actual operations
Include:•Known inputs•Emissions to air•Emissions to water•Emissions to soil•Wastes and emissions sent to treatment
Ability to modify datasets based on your own data
2. As a group, choose one of the four bags and list the processes that are included in the inventory
Life Cycle Inventory
Reusable Plastic Bag Polypropylene, granulate 432.25gExtrusion, plastic film 432.25gTransport, 100km manufacturing to customer 0.043225tkmTransport, municipal waste collection, 10km customer to landfill 0.0043225tkmDisposal, polypropylene, to sanitary landfill 432.25gReusable Cotton Bag Textile, woven cotton, at plant 386.75gTransport, 100km manufacturing to customer 0.03867tkmTransport, municipal waste collection, 10km customer to landfill 0.0038675tkmDisposal, inert material, to sanitary landfill 386.75g
Single Use Plastic Bag Polyethylene, HDPE, granulate 3640gStretch blow moulding 3640gTransport, 100km manufacturing to customer 0.364tkmTransport, municipal waste collection, 10km customer to landfill 0.0364tkmDisposal, polyethylene, 0.4% water, to sanitary landfill 3640gSingle Use Paper Bag Kraft paper, unbleached, at plant 24622.8gProduction of paper bags 24622.8gTransport, 100km manufacturing to customer 2.4623tkmTransport, municipal waste collection, 10km customer to landfill/recycling 0.24623tkmDisposal, packaging paper, to sanitary landfill 12311gRecycling paper 12311g
Step 3: Impact Assessment
• Converts the inventory into impact categories or mid/end points which explain the environmental effect
• Impact categories may include: carcinogens, respiratory organics and inorganics, climate change, radiation, ozone layer, ecotoxicity, acidification/eutrophication, land use, minerals, fossil fuels
• Can apply weights to impact categories
Fate analysisExposure &
effect analysisDamage analysis
Normalization & weighting
Mineral & Fossil
Resources
Ecosystem Quality
Human Health
Impact Assessment
Total Normalized Impact
Normalized Environmental Impact
Step 4: Report Results
• Life cycle interpretation: findings of the inventory analysis or impact assessment are evaluated in relation to the goal and scope of the study to reach conclusions and recommendations
1. Identify significant issues
2. Evaluate results for completeness, consistency, and sensitivity of the data
3. Draw conclusions & make recommendations consistent with the goal & scope of the study
Interpreting Results
• Which bag has the lowest environmental impact? Which bag has the highest?
• Let’s consider cost of the bags.
• As the store owner, does the cost information change which type of bag you would promote? How?
• As a shopper, does the cost information change which type of bag you would use? How?
Bag Type Single use plastic Single use paper Reusable plastic Reusable cotton
Material HDPE Unbleached Kraft paper Polypropylene Cotton
Cost per bag $0.02 $0.07 $1 $6
Cost per year $10.40 $40.46 $4.55 $27.30
Anahita Williamson, PhDDirectorEmail: [email protected] Phone: 585-475-4561
Kate Winnebeck, LCACPSr. Environmental Health & Safety SpecialistEmail: [email protected] Phone: 585-475-5390
New York State Pollution Prevention Institutehttp://www.nysp2i.rit.edu