life cycle assessment: framework

Life Cycle Assessment:Framework

Goal: Life cycle THINKING

• Many “centers” on campus have seminars with lunch and drinks provided. How should drinks be provided?– 12 oz. aluminum cans– 2 L bottles– 10 oz refillable glass bottles– Syrup concentrate

First step toward LCA

• What materials/resources do I need to consider for this analysis?

• Example on board. • List and link materials/resources over

the life cycle for your beverage container. Ignore the soda itself.

Activity Details

• Divide into groups– First - introductions, Second - assign recorder

• 10 minutes list and link materials/resources• 3 minutes each - share• 5 minutes identify common elements

Reflection on Activity

Components of LCA• Scope and Goal definition• Inventory• Impact Assessment• Interpretation (and Improvement)

• Each component included in any methodology followed

• Common terminology

Definitions

• Big set of definitions in ISO framework documents (e.g., p.1 of ISO 14040)

• Won’t review all of them here, but you need to know them.

• Main ones to know are: unit process, elementary flows, inputs, outputs

Definitions• Elementary flows - material or energy

entering or leaving the system, directly to/from the environment, without human transformation

• Unit process - smallest portion of a product being studied for which LCI data available

• Inputs / Outputs - materials or energy entering or leaving a unit process

Scope and Goal: LCA Uses

• Process analysis• Material selection• Product evaluation• Product comparison• Policy-making• Measuring performance• Marketing

Scope Considerations

• Setting all the parameters for study– e.g., functional unit, boundaries, data, etc.– Whether it will be critically reviewed

• Functional unit definition ensures unit consistency for validation and comparison

• May be iterative (update in progress)• Supports product system diagram

Product Systems

• Collections of unit processes, elementary flows, and product flows

• Also shows system boundary• Processes, flows maybe in / out of bounds

– In: fuel, energy, materials, …– Out: emissions, waste, …

Simple Example - Tree

SunlightCO2

O2

Biomass

Environ- ment

Tree EnergySystem?Wate

r

If we wanted to do a life cycle inventory of a tree, we could draw the boundary in one of several places

More Complex Example

• Realize LCA can be used for ‘products’, ‘processes’, ‘systems’, etc.

• We manufacture a part for new automobiles and ship it in cardboard boxes

• Currently, we “ship it and forget it”• Generates significant box waste (not for us!)• We want to reduce waste - how?• What are tradeoffs?

Original System

ManufactureSystem

PackagingTransport/Delivery

Energy

Emissions, Cardboard Box Waste

Car Assembly

Part

Energy

Cardboard Manuf.

UnboxedPart

Raw Mats, Energy

Emissions,Waste

BoxedPart

Packaging Takeback System

Manuf.System

PartPackaging

Transport/Delivery

Emissions, (Less?) Cardboard Waste

Car Assembly

Cardboard Manuf.

Unboxed Part

Empty Box

Transport/Logistics

Reused Box

Energy

Emissions

Packaging Takeback System

• Our new system uses less cardboard– Thus less waste, manufacturing impacts

• But uses more transportation to retrieve used boxes– Thus more energy use, emissions

• Unclear whether this tradeoff is beneficial• Perfect application for LCI/LCA

Example Goal/Scope• Goal: “To determine whether the new system is

better than the old”– More detail: which inventory items? How to assess?– Maybe air emissions, energy use, waste generated– Would a better goal originally have been to do LCA of

old system and suggest improvements?• Scope: Fairly detailed description of both

systems, items in/out of boundaries– e.g., might exclude impacts of product (relevant?)– But include packaging/logistics/reuse of systems

Next Step: Inventory

• In general, just “good research”• “Look up the data, add it up”

– However, data availability varies widely• Consider inputs, outputs of interest

– In: energy, resources, etc.– Out: emissions, waste, etc.

• Also may be iterative• Allocation an issue

Resources

• Don’t despair, you do not need to collect all of your own data for LCAs, for example:– US NREL LCI Database (various):

http://www.nrel.gov/lci/– BEES (construction materials):

http://www.bfrl.nist.gov/oae/software/bees.html

• You should look at these for ideas before finalizing ideas and scope for Course Project

Inventory Interpretation• How do results fit goal/scope?• Assessment of data quality• Sensitivity analysis on inputs/outputs

Improvement

• Are any parts of the inventory obvious targets for change?– Material with high energy requirements– Process with high VOC emissions– Life cycle stage that dominates

Impact?

• Haven’t addressed impact assessment here

• Least developed portion of LCA• Separate science and research• High uncertainty

Criticisms / Limitations• Data reliability and quality is questionable.• Models based on assumptions.• Problem boundaries are arbitrary. • Scale issues - global -> local, etc.• Uncertainty is everywhere• Spatial and temporal issues• Comparisons between studies difficult• No single, accepted method

Important Note on Context

• LCA should be one part of a broad environmental assessment

• If comparing with LCA, all assumptions and methods should be consistent– Especially problematic for validating

against external studies

Reminder: Pre-Assessment

See blackboard site