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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)
Life Cycle Assessment (LCA) 5
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
Life Cycle Assessment (LCA) 6
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
9
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
Life Cycle Assessment (LCA) 13
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)
Life Cycle Assessment (LCA) 16
•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)
Life Cycle Assessment (LCA) 17
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)
Life Cycle Assessment (LCA) 21
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)
Life Cycle Assessment (LCA) 22
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)
Life Cycle Assessment (LCA) 23
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
Life Cycle Assessment (LCA) 25
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/
Life Cycle Assessment (LCA) 26