Life Cycle Assessment
A product-oriented method
for sustainability analysis
UNEP LCA Training Kit
Module b – Overview of LCA
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Contents
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What is LCA?
Why LCA?
The ISO 14040 framework
– Goal and scope definition
– Inventory analysis
– Impact assessment
– Interpretation
What is LCA? (1)
•
•
Officially:
Life Cycle Assessment
Here confined to:
quantitative environmental Life Cycle Assessment of products
– environmental
– Life Cycle
– Assessment
– quantitative
– products
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What is LCA? (2)
• At least three different meanings:
– LCA as a field of study
– LCA as a technique
– LCA as a specific study
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What is LCA? (3)
• Basically: tool for decision-support
– computational aspects
• which data
• which models
• which formulas
– procedural aspects
• who to involve
• how to report
• how to use
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What is LCA? (4)
• ISO-standardised procedure (ISO 14040, created in 19972000; revised in 2006)
– Structured framework: four phases
– Rules, requirements and considerations specified
– Specific data and calculation steps not specified
– Much attention for transparency in reporting
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ISO 14040 framework (1)
Life cycle assessment framework
Goal
and scope
definition
Direct applications:
Inventory
analysis
Interpretation
-
Product development
and improvement
-
Strategic planning
-
Public policy making
-
Marketing
-
Other
Impact
assessment
Source: ISO 14040
ISO 14040 framework (2)
• ISO: Compilation and evaluation of the inputs, outputs and the
potential environmental impacts of a product system
throughout its life cycle
– International Standard ISO 14040
– complementary International Standards ISO 14041,
14042, 14043
– no Technical Report to 14040, but Technical Reports to
14041 and 14042
– 14044 merges the revised 14040-14043 (2006)
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Why LCA? (1)
• Why a product-oriented information tool?
– Increased attention for product policy
• several national policy plans
• EU’s Integrated Product Policy
• UNEP’s International Declaration on Cleaner
Production
• etc.
– Influence consumption and production patterns
• clean(er) production
• ecolabel
• product stewardship
• etc.
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Why LCA? (2)
• Why an integrated information tool?
– Prevent problem shifting
• to other life cycle stages
• to other substances
• to other environmental problems
• to other countries
• to the future
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Why LCA? (3)
• Why a method?
– To structure the large amount of complex data
– To facilitate comparisons across product alternatives
– To enable benchmarking
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Why LCA? (4)
• Why complex data?
Product property
Incandescent lamp
Fluorescent lamp
power consumption
60 W
18 W
life span
1000 hr
5000 hr
mass
30 g
540 g
mercury content
0 mg
2 mg
etc
…
…
ISO 14040 framework (3)
Life cycle assessment framework
Goal
and scope
definition
Direct applications:
Inventory
analysis
Interpretation
-
Product development
and improvement
-
Strategic planning
-
Public policy making
-
Marketing
-
Other
Impact
assessment
Source: ISO 14040
Phase 1: Goal and scope definition (1)
• Phase of life cycle assessment in which the aim of the study,
and in relation to that, the breadth and depth of the study is
established
– goal definition
– scope definition
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Phase 1: Goal and scope definition (2)
• Goal definition:
– intended application
• product development and improvement
• strategic planning
• public decision making
• marketing
• other
– reasons for carrying out the study
– intended audience
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Phase 1: Goal and scope definition (3)
• Scope definition:
– function, functional unit and reference flow
– initial choices
• system boundaries
• data quality
• …
– critical review and other procedural aspects
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Phase 1: Goal and scope definition (4)
• Functional unit:
– comparison on the basis of an equivalent function
– example: 1000 liters of milk packed in glass bottles or
packed in carton, instead of 1 glass bottle versus 1 carton
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Phase 1: Goal and scope definition (5)
• Critical review and other procedural aspects
– critical review to ensure the consistency, scientific validity,
transparency of the report, etc.
– internal review, external review, review by interested
parties
– procedural embedding of LCA: LCA as a (participatory)
process
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Phase 2: Inventory analysis (1)
• Phase of life cycle assessment involving the compilation and
quantification of inputs and outputs, for a given product
system throughout its life cycle
• Steps:
– preparing for data collection
– data collection
– calculation procedures
– allocation and recycling
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Phase 2: Inventory analysis (2)
• Central position for unit process
– smallest portion of a product system for which data are
collected
• Typical examples:
– electricity production by coal combustion
– PVC production
– use of a passenger car
– recycling of aluminum scrap
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Phase 2: Inventory analysis (3)
• Data collection for unit processes:
– flows of intermediate products or waste for treatment
– elementary flows from or to the environment
coal
electricity
electricity production
generator
fly ash
Phase 2: Inventory analysis (4)
equipment
• Combination of unit
processes into a
product system
• Graphical
representation in a flow
diagram
coal mining
coal
steel
generator production
generator
electricity production
product system
fly ash
system boundary
fly ash treatment
gypsum
electricity
reference flow
Phase 2: Inventory analysis (5)
Source: http://www.fibersource.com/f-tutor/LCA-Page.htm
Phase 2: Inventory analysis (6)
• Calculation procedures
– relate process data to the functional unit (matrix algebra)
– allocation of multiple processes (multiple outputs, multiple
inputs, re-use and recycling)
coal
generator
electricity
electricity production
with cogeneration
of heat (CHP)
heat
fly ash
– aggregation over all unit processes in the inventory table
Phase 2: Inventory analysis (7)
• Inventory table
Elementary flow
Incandescent lamp
Fluorescent lamp
CO2 to air
800000 kg
50000 kg
SO2 to air
1000 kg
80 kg
Copper to water
3g
20 g
Crude oil from earth
37000 kg
22000 kg
etc
…
…
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Phase 3: Impact assessment (1)
• Assessment of the importance of the potential environmental
effects with the aid of the results of the inventory analysis
• Steps:
– selection and definition of impact categories, indicators
and models
– classification
– characterisation
– normalisation
– aggregation and/or weighing
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Phase 3: Impact assessment (2)
Example
Cd, CO2, NOx, SO2, etc.
(kg/functional unit)
Impact
category
LCI results assigned to
impact category
Acidification
Acidifying emissions
(NOx, SO2, etc.
assigned to acidification)
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Draf t
Life cycle inventory results
Characterisation model
Category indicator
Proton release
(H+ aq)
Environmental relevance
Category endpoint(s)
- forest
- vegetation
- etc.
Phase 3: Impact assessment (3)
• Example of a category indicator
– Global Warming:
Global Warming Potential (GWP): measure for Global
Warming in terms of radiative forcing of a mass-unit
Example calculation:
5 kg CO2 (GWP = 1)
+
3 kg CH4 (GWP = 21)
=
1 x 5 + 21 x 3 kg CO2 - equivalents (= 68 kg CO2 –
equivalents)
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Phase 3: Impact assessment (4)
• Characterisation:
• Simple conversion and aggregation of GHGs:
IndicatorResultcat 
 CharFactcat ,subs  InventoryResultsubs
subs
GWP (1 and 21)
CO2, CH4
68 kg CO2-eq
5 and 3 kg
climate change
IPCC climate model
infrared radiative forcing
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Phase 3: Impact assessment (5)
• Impact categories, characterisation methods and
characterisation models: some baseline examples
impact category category indicator characterisation model characterisation
factor
abiotic depletion ultimate reserve irt Guinee & Heijungs 95
ADP
annual use
climate change infrared radiative
IPCC model
GWP
forcing
stratospheric
strat. ozone
WMO model
ODP
ozone depletion breakdown
human toxicity
PDI/ADI
Multimedia model, e.g.
HTP
EUSES, CalTox
ecotoxicity
PEC/PNEC
Multimedia model, e.g.
AETP, TETP, etc.
(aquatic,
EUSES, CalTox
terrestrial etc.)
photo-oxidant
trop. ozone
UNECE Trajectory model POCP
formation
formation
acidification
deposition/ac.critical RAINS
AP
load
...
...
...
...
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Phase 3: Impact assessment (8)
Impact category
Incandescent lamp
Fluorescent lamp
Climate change
120000 kg CO2-eq
40000 kg CO2-eq
Ecotoxicity
320 kg DCB-eq
440 kg DCB-eq
Acidification
45 kg SO2-eq
21 kg SO2-eq
Depletion of resources
0.8 kg antinomy-eq
0.3 kg antinomy-eq
etc
…
…
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Phase 3: Impact assessment (7)
• Impact category results still difficult to understand:
– difference in units
– difference in scale
• Normalisation step to relate the results to a reference value
– e.g., total world impacts in 2002
– result often referred to as the normalised environmental
profile
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Phase 3: Impact assessment (8)
Impact category
Incandescent lamp
Fluorescent lamp
Climate change
1.210-11 yr
410-12 yr
Ecotoxicity
1.610-10 yr
2.210-10 yr
Acidification
910-11 yr
4.210-11 yr
Depletion of resources
2410-12 yr
910-13 yr
etc
…
…
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Phase 3: Impact assessment (9)
• Even after normalisation no clear answer
– aggregation of (normalized) impact category results into a
single index
– subjective weighting factors needed
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Phase 3: Impact assessment (10)
• Example of a weighted environmental index
Weighed index
Incandescent lamp
Fluorescent lamp
Weighted index
8.510-10 yr
1.410-10 yr
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Phase 4: Interpretation (1)
• Conclusions, recommendations, analysis, all related to goal
and scope of the research
– among others based on data quality and sensitivity
analysis
– also: critical review by independent experts
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Phase 4: Interpretation (2)
• Example of a contribution analysis
Process
Incandescent lamp
Fluorescent lamp
Electricity production
88%
60%
Copper production
5%
15%
Waste disposal
2%
10%
Other
5%
15%
Total climate change
120000 kg CO2-eq
40000 kg CO2-eq
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Phase 4: Interpretation (3)
• Example of an uncertainty analysis
climate change
160000
140000
120000
100000
80000
60000
40000
20000
0
Incandescent lamp
Fluorescent lamp