Life Cycle Assessment (LCA)
Sustainable Operations
Prof. Gil Souza
Life Cycle Assessment (LCA)
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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)
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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)
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Structure / Scope of LCA
Cradle to Gate
Includes 4 stages
Cradle to Grave
Includes 6 stages
Life Cycle Assessment (LCA)
Source: P&G website
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LCA Phases (ISO 14040 and 14044)
Goal and Scope
Definition
(Determining
boundaries for study)
Interpretation
Inventory Analysis
(Data on inputs and
outputs quantities for
all relevant processes)
(Major
contributions,
sensitivity analysis:
what can be learned
from study?)
Impact Assessment
(Contribution to impact
categories, such as
energy consumption,
through normalization
and weighing
Life Cycle Assessment (LCA)
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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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Step 1: Determining Scope
Example
Life Stage
Resource
extraction
Product
manufacture
Packaging and
transportation
Product use or
consumption
Maintenance,
recycling and
disposal
Product Assessment Matrix
Environmental concern
Materials
Solid
Liquid
Energy use
choice
residues residues
Gaseous
residues
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
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MOT
Sustainability
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
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Energy Use (GJ / Mg) in Production of
Various Metals
Metal
Primary
Production
31
Secondary
Production*
9
91
13
270
17
Zinc
61
24
Lead
39
9
430
140
Steel
Copper
Aluminum
Titanium
* Consumer recycled material
Source: P. Chapman and F. Roberts, 1983
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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
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Life Cycle Assessment (LCA)
Liquid Residues of Common Industrial Processes and
Products
Process
Liquid Species
Trace
Metals
Agriculture
Chemical Mfg.
Nutrients
•
+
Electronics
Electroplating
•
*
Food production
+
Mining, smelting
Acids
Suspended
Solids
•
•
*
*
+
*
+
+
+
+
Metal cleaning
Organics
*
Fertilizer
Leather making
Solvents,
Oils
*
*
*
*
*
*
•
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
Energy to make
Solid waste
Total emissions to air
1.7 mJ
50 g
2.6 kg
Plastic Bag
Oil / gas (nonrenewable)
1.5 mJ
14 g
1.1 kg
Global warming
equivalents (CO2
equivalents)
0.23 kg
0.53 kg
Raw materials
Paper Bag
Wood (renewable)
Source: Institute for Lifecycle Energy Analysis
Compares one paper bag with two plastic bags (similar carrying capacity)
Assumes current recycling rates
It depends!
Life Cycle Assessment (LCA)
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Example of LCA 2: Impact on Global
Warming of Different NEC Products
Electricity Cell Phones
cons. (use)
4%
Assembly
at NEC
7%
Distribution
0.5%
Disposal
0.5%
Fax Machines
Distribution
0.4%
Disposal
0.1%
Purchased
parts
23%
Purchased
parts
88%
Desktop PCs
Assembly at
NEC
1%
Electricity
cons. (use)
76%
Distribution
1.0%
Disposal
0.2%
Assembly
at NEC
1%
Switching Equipment
Purchased
parts
2%
Electricity
cons. (use) Purchased
39%
parts
59%
Assembly
at NEC
1%
Electricity
cons.
(use)
98%
Life Cycle Assessment (LCA)
Source: www.nec.co.jp
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Example of LCA 3: Lamps (Energy Consumption)
Lamps in Comparison
(Use During 25,000 Hours)
Energy [kW]
3500
3000
2500
2000
1500
1000
500
0
Use [kWh]
Production [kWh]
25 x GLS
3290
15.3
2.5 x GFL
658
10.2
Life Cycle Assessment (LCA)
1 x LED
658
9.9
Source: www.osram-os.com
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Example of LCA 3: Lamps (Toxicity Potential)
•Toxicity here is mainly caused by power
consumption due to by-products: arsenic, sodium
dichromate, hydrogen fluoride
•Measured in 1,4 dichlorobenzene equivalent
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Example of LCA 4: Corrosion
Protection Systems (After Scaling)
Source: Technical University of Berlin
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Example of LCA 5: Materials for
Residential Construction
Life Cycle Assessment (LCA)
Source: Kozak and Galston (2001) 18
Application of LCA
Which option is better for the environment:
remanufacturing or recycling?
Answer: It depends!
(But remanufacturing is typically better)
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Example A. Two Automotive Parts (Low Level of
Technological Obsolescence)
Energy consumption (KWh/ton) for steel part:
(gear) alternatives for end-of-life
Energy consumption (KWh/ton) for aluminum part
(transmission): alternatives for end-of-life
30000
7000
29450
6000
25000
6205
5000
20000
4000
15000
3000
3150
10000
2000
5000
4405
2597
0
1000
742
0
Disposal
Recycling
Remanuf.
Disposal
Recycling
Remanuf.
•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
Remanufacturing is clearly better!
Life Cycle Assessment (LCA)
Source: Bert Bras (2009)
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Example B. Cell Phones: Impact on Global
Warming (Primarily Energy Consumption)
Electricity
cons. (use)
4%
Assembly at
NEC
7%
Cell Phones
Distribution
0.5%
Disposal
0.5%
Purchased
parts
88%
Most carbon footprint (and also energy use) occurs in
purchased pars (manufacturing and raw material extraction.)
Remanufacturing is best!
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Example C. Desktop PCs: Impact on Global
Warming (Primarily Energy Consumption)
Desktop PCs
Electricity
cons. (use)
39%
Assembly at
NEC
1%
Distribution
1.0%
Disposal
0.2%
Purchased
parts
59%
Most carbon footprint (and also energy use) occurs in
purchased pars (manufacturing and raw material extraction.)
Remanufacturing is best!
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Example D. Internet Switching Equipment: Impact on
Global Warming (Primarily Energy Consumption)
Switching Equipment
Purchased
parts
2%
Assembly
at NEC
1%
Electricity
cons. (use)
98%
Most carbon footprint (and also energy use) occurs during the use.
Recycling is best, if newer equipment is more energy efficient!
Life Cycle Assessment (LCA)
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Example E. Refrigerators: Impact on Cumulative
Energy Consumption
Distribution
Manufacturing
Use
Again, most energy consumption occurs in usage. Best to replace
old appliances with energy efficient new appliances.
Recycling is best!
Source: Quariguasi Frota Neto et al. 2008
Sustainable Operations
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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 socioeconomic 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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