Life Cycle Assessment (LCA)

Sustainable OperationsProf. Gil Souza

1Life Cycle Assessment (LCA)

Quizzes • For each pair of products / processes below,

which one has the lowest environmental impact?– PET or aluminum packaging for soft drinks?– Remanufacturing or recycling?– Paper or plastic bags?– Ethanol or gasoline for powering automobiles?– Compact dish detergent or regular dish

detergent?– LED lights or CFL lights or incandescent lights?

Life Cycle Assessment (LCA) 2

Answer: You Need Life Cycle Assessment (LCA)

• LCA’s goal is to find the full range of environmental (and societal) damages assignable to products (or a process) through its entire life cycle – Raw material extraction and processing, manufacturing,

distribution, use, and disposal / recycling• Common categories of assessed damages (but not

limited to)– Global warming, toxicity (air, water, and land), ozone

layer depletion, acid rain, depletion of minerals and fossil fuels

• Data intensive process, usually done through software and existing databases

Life Cycle Assessment (LCA) 3

Structure / Scope of LCA

Life Cycle Assessment (LCA) 4Source: P&G website

Cradle to GateIncludes 4 stages

Cradle to GraveIncludes 6 stages

LCA Phases (ISO 14040 and 14044)

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Goal and Scope Definition

(Determining boundaries for study)

Goal and Scope Definition

(Determining boundaries for study)

Inventory Analysis (Data on inputs and

outputs quantities for all relevant processes)

Inventory Analysis (Data on inputs and

outputs quantities for all relevant processes)

Impact Assessment (Contribution to impact

categories, such as energy consumption,

through normalization and weighing

Impact Assessment (Contribution to impact

categories, such as energy consumption,

through normalization and weighing

Interpretation(Major

contributions, sensitivity analysis:

what can be learned from study?)

Interpretation(Major

contributions, sensitivity analysis:

what can be learned from study?)

Step 1: Determining Goal• Level of specificity in the study

– Is the product being analyzed specific to a company or a plant? Two different plants producing the same type of product could have different emission levels, for example• This requires an additional level of data collection that may be impractical

– Or, will we focus on industrial averages (e.g., impacts of using recycled aluminum in a design)?

• Level of accuracy in data collection / analysis– Should be high if used in driving public policy– If used in internal decision making for a firm, a reasonable estimate is

generally enough• How to display the results. Example: comparing two products

– Comparison should be made in terms of equivalent use– Example: bar soap vs. liquid soap; the basis should be an equal

number of hand washings

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Life StageMaterials choice

Energy useSolid residues

Liquid residues

Gaseous residues

Resource extractionProduct manufacturePackaging and transportationProduct use or consumptionMaintenance, recycling and disposal

Product Assessment MatrixEnvironmental concern

Step 1: Determining ScopeExample

Step 2: Inventory Analysis• Collect data on the impact of inputs and outputs

generated by each row (life cycle stage) on the assessed category of interest. Categories on previous example:– Materials choice– Energy use– Solid residues– Liquid residues– Gas residues

• Many databases exist for common materials and processes used (industry averages)

• Mostly done through software

8 MOTSustainability

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Materials Choice

• Recommendations based on availability on Earth, rate of depletion and toxicity

• Recommended:– Al, Br, C, Fe, H, Mn, N, O, S, Si, and Ti– Supplies are ample, potential for recycling is

good, and have no significant toxicity issues• Limit or avoid:– Ag, As, Au, Cd, Cl, Cr, Hg, Ni, Pb– Short supply and/or toxicity problems

10 Life Cycle Assessment (LCA)

Energy Use (GJ / Mg) in Production of Various Metals

Metal Primary Production

Secondary Production*

Steel 31 9

Copper 91 13

Aluminum 270 17

Zinc 61 24

Lead 39 9

Titanium 430 140* Consumer recycled material

Source: P. Chapman and F. Roberts, 1983

11 Life Cycle Assessment (LCA)

Solid Residues• Process residues– A result of manufacturing process– Example: fly ash from coal combustion

• Product residues– Intended to be part of the product– Example: plastic molding

• Packaging residues– 30% of all municipal solid waste…but– 40% of all U.S. goods are purchased by corporations

Liquid Residues of Common Industrial Processes and Products

Process Liquid Species

Trace Metals

Nutrients Solvents, Oils

Organics Acids Suspended Solids

Agriculture • • •

Chemical Mfg. + * * +

Electronics * +

Electroplating • * +

Fertilizer * +

Food production +

Leather making + *

Metal cleaning * * * *

Mining, smelting * •

Pesticides ** = Modest influence on local, regional or global scale; + = minor influence on local, regional, or global scale; • = major influence on local, regional, or global scale

Source: T. Graedel and B. Allenby, “Design for Environment”.

Example of LCA 1: Paper vs. Plastic Bag

Category Paper Bag Plastic Bag

Raw materials Wood (renewable) Oil / gas (non-renewable)

Energy to make 1.7 mJ 1.5 mJSolid waste 50 g 14 gTotal emissions to air 2.6 kg 1.1 kgGlobal warming equivalents (CO2 equivalents)

0.23 kg 0.53 kg

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Source: Institute for Lifecycle Energy AnalysisCompares one paper bag with two plastic bags (similar carrying capacity)Assumes current recycling rates

It depends!It depends!

Example of LCA 2: Impact on Global Warming of Different NEC Products

Life Cycle Assessment (LCA) 14Source: www.nec.co.jp

Example of LCA 3: Lamps (Energy Consumption)

Life Cycle Assessment (LCA) 15Source: www.osram-os.com

Example of LCA 3: Lamps (Toxicity Potential)

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•Toxicity here is mainly caused by power consumption due to by-products: arsenic, sodium dichromate, hydrogen fluoride•Measured in 1,4 dichlorobenzene equivalent

Example of LCA 4: Corrosion Protection Systems (After Scaling)

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Source: Technical University of Berlin

Example of LCA 5: Materials for Residential Construction

Life Cycle Assessment (LCA) 18Source: Kozak and Galston (2001)

Application of LCAWhich option is better for the environment:

remanufacturing or recycling?

Answer: It depends!(But remanufacturing is typically better)

19Life Cycle Assessment (LCA)

Example A. Two Automotive Parts (Low Level of Technological Obsolescence)

6205

3150

742

0

1000

2000

3000

4000

5000

6000

7000

Disposal Recycling Remanuf.

Energy consumption (KWh/ton) for steel part: (gear) alternatives for end-of-life

29450

4405 25970

5000

10000

15000

20000

25000

30000

Disposal Recycling Remanuf.

Energy consumption (KWh/ton) for aluminum part (transmission): alternatives for end-of-life

Source: Bert Bras (2009)

•In “disposal” a new part has to be produced from virgin raw materials

•In recycling, a new part is produced from recycled materials

•In remanufacturing, the part is remanufactured and reused

20Life Cycle Assessment (LCA)

Remanufacturing is clearly better!

Example B. Cell Phones: Impact on Global Warming (Primarily Energy Consumption)

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Most carbon footprint (and also energy use) occurs in purchased pars (manufacturing and raw material extraction.) Remanufacturing is best!

Example C. Desktop PCs: Impact on Global Warming (Primarily Energy Consumption)

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Most carbon footprint (and also energy use) occurs in purchased pars (manufacturing and raw material extraction.) Remanufacturing is best!

Example D. Internet Switching Equipment: Impact on Global Warming (Primarily Energy Consumption)

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Most carbon footprint (and also energy use) occurs during the use. Recycling is best, if newer equipment is more energy efficient!

Example E. Refrigerators: Impact on Cumulative Energy Consumption

Source: Quariguasi Frota Neto et al. 2008

Again, most energy consumption occurs in usage. Best to replace old appliances with energy efficient new appliances.

Recycling is best!

24Sustainable Operations

DistributionManufacturing

Use

Limitations of LCA: Examples• Weights given to different impacts

– What is more important? Use of water resources or CO2 emissions?

• Drawing the boundaries– Cradle to Gate or Cradle to Grave?– Do we consider supporting activities for the system?

• Example: a warehouse stores the product. Direct energy consumption for the warehouse should be part of the system, but emissions associated with garbage pickup for the facility probability shouldn’t be.

• Social and economic impacts– Environmental impacts are relatively easy to measure, but socio-

economic impacts are difficult to quantify• Renewable vs. non-renewable resources• Remanufacturing, recycling, and reuse

– Consideration of recycling makes significant impact, even though that depends on recycling rates

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Further Resources• The web has an incredible amount of

information on LCA• For starters, please check the document

“LCA_guide_EPA.pdf” on Angel, which has a more detailed guide to LCA (by the EPA), and it includes a list of software vendors

• See http://www.life-cycle.org/

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