Transcript Document
Life Cycle Assessment: Laying the Foundation for a Transparent Supply Chain
Shopping Bag Case Study
September 26, 2013
Dr. Anahita Williamson
Director
Kate Winnebeck
LCACP, Senior EHS Specialist
New York State Pollution Prevention Institute at RIT
Life Cycle Assessment
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) Material Extraction Processing Component Fabrication Product Assembly Packaging & Distribution
Reuse Remanufacture Recycle
Use End of Use Processing
Waste Treatment
LCA Methodology
• A Life Cycle Assessment is carried out in four distinct phases: (ISO 14040, 14044) – Step 1: Goal definition and scoping. is not included in the study) Identify the LCA's purpose, the products of the study, and determine the boundaries. (what is and – Step 2: Life-cycle inventory. phase. Quantify the energy and raw material inputs and environmental releases associated with each life cycle – Step 3: Impact analysis. Assess the impacts on human health and the environment.
– Step 4: Report results. product life-cycle. Evaluate opportunities to reduce energy, material inputs, or environmental impacts at each stage of the
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
Material Extraction Processing Bag Manufacture Packaging & Distribution Single use & reusable plastic bag Extracting petroleum Transform petroleum into plastic Form plastic into bags Packaging & Distribution Paper bag Cutting down trees Transform trees into paper Form paper into bags Packaging & Distribution Use Use Use End of Life Landfill 50/50 to Landfill & Recycling
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
Functional Unit
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
Material Mass per bag Relative Capacity Bags per Year Mass bags per year
Single use plastic
HDPE 7g 1 520 3640g
Single use paper
Unbleached Kraft paper 42.6g
0.9
578 24622.8g
Reusable plastic
Polypropylene 95g 1.1
4.55
432.25g
Reusable cotton
Cotton 85g 1.1
4.55
386.75g
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
Step 2: Life Cycle Inventory
Inventory collected from multiple sources
Inputs
Materials Manufacturing Energy
Outputs
Products Distribution Raw Materials database Customer use Air, Water and Solid Emissions End of use processing
Toner Life-cycle Inventory
Ref: A.Ahmadi,et.al, J.Clean.Prod., 2003
Toner Life-cycle Inventory
Ref: A.Ahmadi,et.al, J.Clean.Prod., 2003
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 Inventory
Peer reviewed datasets imbedded in software Data 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
Single Use Plastic Bag Polyethylene, HDPE, granulate Stretch blow moulding Transport, 100km manufacturing to customer Transport, municipal waste collection, 10km customer to landfill Disposal, polyethylene, 0.4% water, to sanitary landfill Single Use Paper Bag Kraft paper, unbleached, at plant Production of paper bags Transport, 100km manufacturing to customer Transport, municipal waste collection, 10km customer to landfill/recycling Disposal, packaging paper, to sanitary landfill Recycling paper Reusable Plastic Bag Polypropylene, granulate Extrusion, plastic film Transport, 100km manufacturing to customer Transport, municipal waste collection, 10km customer to landfill Disposal, polypropylene, to sanitary landfill Reusable Cotton Bag Textile, woven cotton, at plant Transport, 100km manufacturing to customer Transport, municipal waste collection, 10km customer to landfill Disposal, inert material, to sanitary landfill
3640g 3640g 0.364tkm
0.0364tkm
3640g 24622.8g
24622.8g
2.4623tkm
0.24623tkm
12311g 12311g 432.25g
432.25g
0.043225tkm
0.0043225tkm
432.25g
386.75g
0.03867tkm
0.0038675tkm
386.75g
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
Impact Assessment
Life Cycle Inventory
NOx SOx Pesticides Heavy metals CO2 VOCs Particulates Chemicals
Impact Categories
Concentration in air, water, food Concentration greenhouse gases Changed pH and nutrient availability Change in habitat Fossil fuel availability
Category Indicators
Local effects on species Climate change Ozone layer depletion Radiation Respiratory effects Cancer cases and types Surplus energy Fate analysis Exposure & effect analysis Damage analysis
Damage Categories
Human Health Ecosystem Quality Mineral & Fossil Resources
Single Score Indicator
Normalization & weighting
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.
Bag Type
Material Cost per bag Cost per year
Single use plastic
HDPE $0.02 $10.40
Single use paper
Unbleached Kraft paper $0.07 $40.46
Reusable plastic
Polypropylene $1 $4.55
Reusable cotton
Cotton $6 $27.30
• 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?
Anahita Williamson, PhD
Director Email: [email protected]
Phone: 585-475-4561
Kate Winnebeck, LCACP
Sr. Environmental Health & Safety Specialist Email: [email protected]
Phone: 585-475-5390 New York State Pollution Prevention Institute http://www.nysp2i.rit.edu