Download Life Cycle Impact Assessment

Life Cycle
Impact Assessment
Martin Luther
University
Halle
(Saale)
Industrial
Ecology
– Winter
2006
– Session 5 – January 27
Life Cycle Impact Assessment
Goal and scope
definition
Inventory
analysis
Interpretation
Impact
assessment
Industrial Ecology – Winter 2006 – Session 5 – January 27
CD_JEP-32005-2004
Life Cycle Impact Assessment
Impact Assessment is aimed at understanding and evaluating the magnitude and
significance of the potential environmental impacts of a product system (ISO14040).
Life Cycle Inventories (LCIs
(LCIs)) by themselves do not characterize the environmental
performance of a product system. Impact Assessment (IA) aims at connecting, to
the extent possible, emissions and extractions listed in LCIs on the basis of impact
pathways to their potential environmental damages.
Life Cycle Inventory results
Classification
Impact categories
Characterization
Category indicator results
Normalization
Environmental profile
Weighting
One-dimensional environmental score
Industrial Ecology – Winter 2006 – Session 5 – January 27
Elements of LCIA according to ISO 14042
Mandatory elements
Selection of impact categories, category indicators and characterization models
Assignment of LCI results (classification)
Calculation of category indicator results (characterization)
Category indicator results (LCIA profile)
Optional elements
Normalization of category indicator results relative to reference information
Grouping
Weighting
Data quality analysis
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
The environmental mechanism (impact pathway)
Impact pathways consist of linked environmental processes,
processes and they express the causal
chain of subsequent effects originating from an emission or extraction (environmental
intervention).
Examples:
Increase in effectiveness of communication of results (generally)
SO2
emissions
Acid
rain
Acidified
lake
Source
Dead
fish
Loss of
biodiversity
Endpoint
Midpoint
CFC
emissions
Tropospheric
OD
Stratospheric
OD
UVB
exposure
Human
health
Increase in uncertainty for predicting the environmental impact from the initial interventions
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Impact Categories
According to ISO14042, LCI results are first classified into impact categories that are
relevant and appropriate for the scope and goal of the LCA study.
Example:
Carbon dioxide
Climate change
Methane
CFCs
Stratospheric ozone depletion
Nitrogen oxides
Sulphur dioxide
Photochemical oxidant formation
Acidification
A category indicator,
indicator representing the amount of impact potential, can be located at any
place between the LCI results and the category endpoints. There are currently two main
Impact Assessment methods:
• Problem oriented IA methods stop quantitative modeling before the end of the impact
pathway and link LCI results to so-defined midpoint categories (or environmental
problems), like acidification and ozone depletion.
• Damage oriented IA methods, which model the cause-effect chain up to the endpoints
or environmental damages, link LCI results to endpoint categories.
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Impact categories proposed by UNEP/SETAC Life Cycle Initiative in
in 2003
Midpoint categories
(environmental problems)
Endpoint categories
(environmental damages)
Photochemical oxidant formation
Human toxicity
Human Health
Ozone depletion
Climate change
Biotic & abiotic
natural environment
Acidification
LCI
results
Eutrophication
Biotic & abiotic
natural resources
Ecotoxicity
Land use impacts
Biotic & abiotic
manmade resources
Species & organism dispersal
Abiotic resources depletion
Missing: Casualties
Noise
Biotic resources depletion
Source: Int J of LCA 9(6) 2004
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Classification and characterization
Practical guide to classification and characterization:
• Choose impact categories
• Define a category indicator for each impact category
• Identify those LCI results that contribute to the indicator
• choose characterization model and characterization factor
Characterization model:
The chain of physical, chemical and biological events in the natural environment
that link a particular environmental intervention to a particular impact is called an
environmental process.
For each impact category, the characterization model should model all relevant
environmental processes (to a greater or lesser extent).
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Classification and characterization
Example:
In general:
Cd, CO2, NOX, SO2, etc.
(kg/functional unit)
LCI results
Impact category
LCI results assigned to
Impact category
Characterization model
Category indicator results
Category endpoint
Acidification
Acidifying emissions
NOX, SO2, etc.
(kg/functional unit)
Proton release
(H+ aq)
- Forests
- Fish populations
- etc.
Source: ISO14042
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Classification and characterization – Example 1
Impact category
LCI results
Characterization model
Category indicator
Characterization factor
Unit of indicator result
Substance
ammonia
hydrogen chloride
hydrogen fluoride
hydrogen sulfide
nitric acid
Nitrogen dioxide
Nitrogen monoxide
Sulfur dioxide
Sulphuric acid
Acidification
Emissions of acidifying substances to the air (in kg)
RAINS10 model, developed by IIASA, describing the fate
and deposition of acidifying substances, adapted to LCA
Deposition/acidification critical load
Acidification potential (AP) for each acidifying emission to
the air (in kg SO2 equivalents/kg emission)
kg SO2 eq
AP (in kg SO2 equivalents/kg emission)
1.88
0.88
1.60
1.88
0.51
0.70
1.07
1.00
0.65
Source: (Guinée et al., 2002)
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Classification and characterization – Example 2
Impact category
LCI results
Characterization model
Category indicator
Characterization factor
Unit of indicator result
Stratospheric ozone depletion
Emissions of ozone-depleting gases to the air (in kg)
The model developed by WMO, defining the ozone
depletion potential of different gases
Stratospheric ozone breakdown
Ozone depletion potential in the steady state (ODP∞) for
each emission (in kg CFC-11 equivalents/kg emission)
kg CFC-11 eq
Substance
Halon-1301
Halon-1211
Halon-1202
Tetrachloromethane
CFC-11
CFC-12
HCFC-123
HFC-142b
Methyl Bromide
ODP∞ (in kg CFC-11 equivalents/kg emission)
12
5.11
1.25
1.2
1
0.82
0.012
0.043
0.37
Source: (Guinée et al., 2002)
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Classification and characterization – Example 3
Impact category
Climate change
LCI results
Emissions of greenhouse gases to the air (in kg)
Characterization model
the model developed by the IPCC defining the global
warming potential of different gases
Category indicator
Infrared radiative forcing (W/m2)
Characterization factor
Global warming potential for a 100-year time horizon
(GWP100) for each GHG emission to the air
(in kg CO2 equivalents/kg emission)
Unit of indicator result
kg CO2 eq
Substance
Carbon dioxide
Methane
CFC-11
CFC-13
HCFC-123
HCFC-142b
Perfluoroethane
Perfluoromethane
Sulphur hexafluoride
GWP100 (in kg CO2 equivalents/kg emission)
1
21
4000
11700
93
2000
9200
6500
23900
Source: (Guinée et al., 2002)
Industrial Ecology – Winter 2006 – Session 5 – January 27
Impact Assessment
Summary
• At present, there is no agreement on one standard format for LCIA.
• ISO14042 contains guidelines and recommendation for LCIA.
• According to ISO14042, mandatory elements of LCIAs are
selection of impact categories, category indicators and characterization models,
classification and characterization.
• A very popular method is the so-called problem-oriented (midpoint)
approach that has been developed, amongst others, at CML, University of Leiden,
in The Netherlands.
• Other currently used LCIA methods include damage-oriented (endpoint) methods,
like EPS and Eco-Indicator99 (both Dutch), and distance-to-target methods like the
Critical Volumes approach of BUWAL, the Swiss EPA.
• All examples in this introduction are based on the problem oriented approach
• Normalization is generally recommended and helps to better understand the relative
importance and magnitude of the indicator results.
• Weighting is much debated and ISO14042 explicitly mentions that
they are based on value choices and not on natural science.
Industrial Ecology – Winter 2006 – Session 5 – January 27