LCA in matrix notation

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LCA in matrix notation
Indicatorresults
Referenceflow
Matrices ofprocess inventories
Life cycle inventory
Process activitylevels
Characterizationfactors
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Goal and scopedefinition
Interpretation
Inventoryanalysis
Impactassessment
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Interpretation

• Life Cycle Interpretation is the phase in which
  the results of the study and all choicesand
  assumptions made during its course are evaluated
  in terms of soundness and robustness, and
  overall conclusions are drawn and recommendations
  made.
• ISO14044 distinguishes between three different
  elements
• Identification of significant issues based on
  LCI and LCIA results
• Completeness, sensitivity and consistency checks
• Conclusions, limitation and recommendations
• One of the main aims of Interpretation is to
  check the results of Inventory Analysis and
  Impact assessment against the Goal and Scope
  Definition of the study.

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Interpretation Identification of significant
issues based on LCI and LCIA results

• Significant inventory data such as energy,
  emissions, waste, etc.
• Significant impact categories such as resource
  use, climate change, toxicity, etc.
• Significant contribution from life cycle stages
  such as individual unit processes or whole
  process groups (e.g. use phase)

Typical life cycle GHG emissions of an ICE
passenger car
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Interpretation Completeness, sensitivity and
consistency checks

• Completeness check makes sure that nothing
  important or relevant has been left out (e.g.
  through cut-off, data gaps or missing impact
  category). Relevance of missing elements with
  respect to goal and scope of study needs to
  be discussed
• Sensitivity and uncertainty analysis studies
  the effect of variations in process data,
  boundary, allocation and modeling choices and
  other variables. The objective is to assess the
  reliability and robustness of the LCI and CLIA
  results.
• Consistency check determines whether the
  assumptions, methods, models and data are
  consistent with goal and scope of the LCA
  study and with each other. Examples are
  consistency in - data quality along a product
  life cycle or between different product systems
  - regional and temporal aspects - allocation
  rules and system boundaries - impact assessment

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Interpretation Conclusions, limitation and
recommendations

• Conclusions are based on the significant
  findings and their robustness.
• Limitations are based the completeness,
  sensitivity and consistency checks.
• Recommendations are based on the conclusions
  and their limitations.

• ISO 14044 also provides guidelines on
• how to report of LCA studies
• how to conduct a critical review of an LCA study

Critical reviews by external experts or panels on
interested parties are especially important if
the LCA study is intended to be used for a
comparative assertion intended to be disclosed to
the public.
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Case study Disposable versus reusable diapers

• Background
• When Proctor Gamble (PG) launched Pampers
  disposable diapers in the 1960s, it was
  considered to be the product breakthrough of the
  decade.
• By the early 1990s, Pampers contributed over 18
  to the companys annual revenues.
• It also became a symbol of the throw-away
  society and was targeted by NGOs.
• To deflect criticism, PG commissioned Arthur D.
  Little to conduct a Life Cycle Assessment of
  both types of diapers to settle the debate.

• The Life Cycle Asessment
• Arthur D. Little researchers started by defining
  a functional unit and the resulting reference
  flows. They made the following simplifying
  assumption
• The number of daily diaper changes is the same
  for both types of diapers.
• Based on the reference flows life cycle
  inventories for both product systems were
  calculated. The following assumption was made
• 90 of all reusable diapers are laundered at
  home.

Source World Resources Institute, 1994
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Case study Disposable versus reusable diapers
Raw cotton
Cotton fabric
Reusable diaper
Diaper use
Diaper laundry
Diaper landfill
Other materials
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Pulp and paper
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Absorbent gel
LDPE film PP fabric
Disposable diaper
Diaper use
Diaper landfill
Tapes, elastics, adhesives
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Source World Resources Institute, 1994
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Case study Disposable versus reusable diapers
Functional unit Weekly diaper needs
Source World Resources Institute, 1994
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Case study Disposable versus reusable diapers
This graph compares from two different sources,
Allen et al. (1992) which report data from a
Franklin Associates Study (1992) and the World
Resources Institute (WRI, 1994) which reports
data from the Arthur D. Little study (1990)
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Case study Disposable versus reusable diapers
The results from Allen et al. are mostly higher
than those from the WRI, up to a factor of 6.
The differences between disposable and reusable
diapers are smaller in the Allen et al. results
compared to the WRI results. However, the
general direction of the results are identical
Reusable diapers consume more energy and more
water consume less raw materials generate mor
e emissions to air and water generate less
waste

• Summary
• Many environmental choices are about trade-offs
  between different types of burdens
• Without impact assessment these burdens are very
  difficult to compare
• Without common methodology LCA results are very
  difficult to reproduce
• LCA results without comprehensive documentation
  are not very useful
• LCA methodology has come a long way since the
  early 1990s

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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
Commissioner
LCA practitioner
Goal
Compile life cycle inventory and compare
potential environmental impacts of production,
use and disposalof reusable and disposable
nappies
Scope
Temporal coverage 2001-2002 Allocation Physical
relationship, economic for retail energy
use Cut-off Capital equipment and human labor
excluded
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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
The use of nappies during the first 2.5 years of
a childs life, in the UK, for the period
2001-2002
Functional unit
Reference flows

• 4.16 disposable nappies of 44.6g daily over 2.5
  years
• 47.5 reusable nappies

• CML 2000 mid-point indicators
• global warming
• ozone depletion
• photo-oxidant formation
• depletion of abiotic resources
• eutrophication
• acidification
• human, aquatic and terrestrial toxicity

Impact categories
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Process flow diagram disposable nappies
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Process flow diagram home laundered reusable
nappies
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Process flow diagram commercially laundered
reusable nappies
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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
Normalization factor
Total estimated impact of Western Europe in 1995
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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
Sensitivity Analysis
Number of changes
Excreta as putrescible waste
Omitted materials
Equivalent COD and BOD emissions
Percentage of tumble drying
Average age of washing machines
Number of reusable nappies
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Life Cycle Assessment of Disposable and Reusable
Nappies in the UK
Conclusions
There is no significant difference between any of
the environmental impacts of the disposable, home
use reusable and commercial laundry systems that
were assessed.
Main sources of environmental impact Disposables
Reusables
Raw material production and conversion of nappy
components
Fuels and electricity used in washing and drying
Waste management
No substantial contribution to total impact
Main opportunities for improvement Disposables R
eusables
Mass reduction and improved materials
manufacturing
Increase energy efficiency of washing and drying
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The Use of Life Cycle Assessments
Who are the users? What are the uses?

• LCA
• Goal Scope
• Life Cycle Inventory
• Impact Assessment
• Interpretation

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The Users of Life Cycle Assessments

• Companies Especially in Scandinavian
  countries, Japan, Holland, Germany, Switzerland
  (e.g. Volvo, Electrolux, Honda, Toyota, Proctor
  Gamble, Unilever, Corus, Arcelor, Alcan,
  etc.) Through in-house experts, LCA
  consultancies or universities.

• Trade associations Especially for material
  commodities (e.g. plastics, steel, aluminum,
  concrete, etc.) Through the experts of their
  member companies, LCA consultancies or
  universities.

• NGOs Mostly commissioned to external LCA
  consultancies or universities.

• Government agencies Especially in
  Scandinavian countries, Japan, Holland, Germany,
  Switzerland, EU Through in-house experts, LCA
  consultancies or universities.

• Business analysts Typically analyze
  externally created LCA information on businesses
  and sectors.

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The Use of Life Cycle Assessments

• Companies Originally intended for external
  use, e.g. marketing. However, currently mainly
  for internal use due to bad initial
  experiences of external uses. Currently
  mainly retrospective and for learning proposes,
• instead of prospective use for decision making
  purposes. Currently, decisions based on LCA
  results are more operational than strategic.

• Trade associations Trade associations of
  material commodities producers more frequently
  use LCA for external purposes (e.g. marketing,
  as lobbying tool in the policy process).

• NGOs To create scientific foundations of
  campaigns or investigate claims by industry.

• Government agencies To analyze and design
  environmental policies and regulations
  (especially by the EPAs of European
  countries). EUs Integrated Product Policy
  recommends LCA.

• Business analysts To analyze and rate
  individual companies and industry sectors.

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Internal vs. external use of Life Cycle
Assessments

• Most companies currently use LCA for internal
  purposes.
• Internal uses are
• Hotspot analysis of existing or planed products
• Compare existing products with products under
  development
• Product/process design (short-term, operational)
• Product/process development (long-term,
  strategic)

• As LCA methodology matures, so do the number and
  frequency of external uses .
• External uses are
• Marketing, especially final product comparisons
  (credibility and complexity issues)
• Lobbying, especially commodity comparisons
• Providing information and education to customers
  and other stakeholders
• Eco-labeling (also called environmental product
  declarations EPDs)

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Simplified (Streamlined) Life Cycle Assessments

• Reasons for conducting simplified LCAs
• Lack of data
• Lack of information
• Lack of knowledge
• Lack of time and money
• Use as screening step prior to a comprehensive
  LCA

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Simplified (Streamlined) Life Cycle Assessments

• Ways to simplify LCAs
• consider only a limited set of elementary flows
  (inputs and outputs)
• consider only a limited amount of impact
  categories
• simplify the product system under investigation
• exclude certain product components or materials
• exclude certain processes
• use simplified models of products and processes
• consider only a limited set of life cycle stages
  (e.g. cradle-to-gate assessments)
• in comparative LCAs, consider only those system
  aspects that are different between the
  alternatives of providing the functional unit
• simplify the impact assessment methodology
• conduct only an inventory analysis
• use qualitative instead of quantitative methods

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Simplified (Streamlined) Life Cycle
AssessmentsExample The Environmentally
Responsible Product Assessment Matrix
(Graedel et al., Env. Sci. Tech., 29, 1995)
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Simplified (Streamlined) Life Cycle
AssessmentsExample The Environmentally
Responsible Product Assessment Matrix used to
compare 1950s and 1990s vehicles
Product manufacture ratings
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Simplified (Streamlined) Life Cycle
AssessmentsExample The Environmentally
Responsible Product Assessment Matrix used to
compare 1950s and 1990s vehicles
Product use ratings
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Simplified (Streamlined) Life Cycle
AssessmentsExample The Environmentally
Responsible Product Assessment Matrix used to
compare 1950s and 1990s vehicles
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Outlook and future developments

• Issues to be solved
• Availability and quality of data (especially
  important of SMEs) Development of publicly
  shared databases
• Impact assessment methodology not fully mature
  (especially toxicity indicators)
• Multidimensionality (multi criteria decision
  making)
• Relationship with Environmental Management
  Systems
• Product perspective is not whole system
  perspective (Most important example economic
  relationships)

• Technical developments
• Consequential LCA (to resolve allocation
  issues)
• Hybrid LCA (ProcessI/O LCA) (to resolve cut-off
  issues)
• Modeling economic relationships in and between
  product systems
• Modeling non-linear and dynamic relationships in
  and between product systems
• Modeling spatial aspects of LCI and LCIA