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Industrial Ecology – Winter 2006 – Session 7 – February 1 - Bren

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Industrial Ecology – Winter 2006 – Session 7 – February 1 - Bren Powered By Docstoc
					       Goal and scope
         definition




          Inventory
                                     Interpretation
           analysis




           Impact
         assessment




Industrial Ecology – Winter 2006 – Session 7 – February 1
                                   Interpretation


Life Cycle Interpretation is the phase in which the results of the study and all choices
and assumptions made during its course are evaluated in terms of soundness and
robustness, and overall conclusions are drawn and recommendations made.

ISO14043 makes recommendations but does not prescribe a fixed methodology.

Soundness can be checked through:
• Consistency check
• Completeness check
• Contribution analysis
Robustness can be check through:
• Perturbation analysis
• Sensitivity and uncertainty analysis


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.


             Industrial Ecology – Winter 2006 – Session 7 – February 1
                                    Interpretation
• Consistency check
  determines whether the assumptions, methods, models and data are consistent with
  goal and scope of the LCA study and with each other
• Completeness check
  makes sure that nothing important or relevant has been left out (e.g. through cut-off
  or data gaps or estimates)
• Contribution analysis
  establishes the contribution of various identifiable elements and parameters to the
  overall LCA result, e.g. an individual process, a group of processes, a life cycle stage,
  the packaging of the product, a specific intervention (like SO2 emissions).
• Perturbation analysis
  also known as marginal analysis, studies the effects of small parameter changes to
  the overall results.
• Sensitivity and uncertainty analysis
  studies the effect of variations in process data, boundary, allocation and model
  choices and other variables.




               Industrial Ecology – Winter 2006 – Session 7 – February 1
                                 Interpretation
               Case study 1: Disposable versus reusable diapers
Background:
• When Proctor & Gamble (P&G) 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 company’s annual revenues.
• It also became a symbol of the ‘throw-away’ society and was targeted by NGOs.
• To deflect criticism, P&G commissioned Arthur D. Little in 1990 to conduct a
   Life Cycle Analysis of both types of diapers to settle the debate.

The Life Cycle Analysis:
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.
Response:
• As a response to Arthur D. Little’s results, Greenpeace commissioned its own LCA.
  Here are the results of both studies:

               Industrial Ecology – Winter 2006 – Session 7 – February 1
                                 Interpretation
               Case study 1: Disposable versus reusable diapers


Results from Study A
  30


  25


  20

                                                                                                Disposable
  15
                                                                                                Reusable

  10


   5


   0
         Raw          Energy       Water    Emissions   Waste water Process         Post-
       materials    (10,000Btu)   (10gal)      to Air    effluents  waste (lbs)   consumer
         (lbs)                               (lbs/10)    (lbs/100)                waste (lbs)


                              Functional unit: Weekly diaper needs

                   Industrial Ecology – Winter 2006 – Session 7 – February 1
                                 Interpretation
               Case study 1: Disposable versus reusable diapers


Results from Study B
  160

  140

  120

  100
                                                                                                  Disposable
   80
                                                                                                  Reusable
   60

   40

   20

    0
          Raw         Energy    Water (gal)   Emissions     Waste      Process        Post-
        materials   (1000Btu)                    to Air     water     waste (lbs)   consumer
          (lbs)                               (lbs/100)   effluents                 waste (lbs)
                                                          (lbs/100)


                            Functional unit: Weekly diaper needs

               Industrial Ecology – Winter 2006 – Session 7 – February 1
                           Interpretation
         Case study 1: Disposable versus reusable diapers


Question:
Which case study was commissioned by which organization?

Proctor & Gamble                                    Study A

Greenpeace                                          Study B

Answer:
Both graphs show the results of Study A.

However, the Arthur D. Little study was only one of many LCAs that were
performed to compare disposable and reusable diapers.
Their conflicting results due to different inventory data, model assumptions,
boundary choices and calculation methods have prevented a
generally accepted conclusion.



          Industrial Ecology – Winter 2006 – Session 7 – February 1
                                    Interpretation
                  Case study 1: 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):


    1
  0.9
  0.8
  0.7
                                                                                  ALLEN DATA Disposable
  0.6
                                                                                  WRI DATA Disposable
  0.5
                                                                                  ALLEN DATA Reusable (10/90)
  0.4
                                                                                  WRI DATA Reusable (10/90)
  0.3
  0.2
  0.1
    0
          Energy          Water      Enissions to   Emission to    Solid waste
        (million Btu)   (1000 gal)     air (lbs)     water (lbs)   (cubic feet/
                                                                       lbs)




                   Industrial Ecology – Winter 2006 – Session 7 – February 1
                              Interpretation
            Case study 1: Disposable versus reusable diapers




The data from Allen et al. is almost consistently higher than the data from the WRI,
up to a factor of 6.
The ratios between disposable and reusable diaper data is consistently smaller in
the Allen et al. data compared to the WRI data.
However, the general directions of the results are identical:
Reusable diapers consume             more energy and more water
                  consume            less raw materials
                  generate           more emissions to air and water
                  generate           less waste




             Industrial Ecology – Winter 2006 – Session 7 – February 1
                              Interpretation
            Case study 1: Disposable versus reusable diapers




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




             Industrial Ecology – Winter 2006 – Session 7 – February 1
                            Interpretation
                Case study 2: Resilient Floor Coverings

Products considered: Floorings based on
• Polyvinyl chloride (PVC), polymer of CH2=CHCl. PVC products contain
  Phthalates which can leach out. PVC production also generates dioxins as
  production by-products.
• Polyolefins, which is the collective name for Polyethylene (PE) and
  Polypropylene (PP).
• Linoleum, which is made of linseed oil and wood flour on a carrier of jute


Case study is based on
Günther & Langowski (1997) Life Cycle Assessment Study on Resilient Floor
Coverings, International Journal of LCA 2(2), pp. 73 – 80


The LCA study excluded the use phase of the product, i.e. only contains the
production and end-of-life stages.


           Industrial Ecology – Winter 2006 – Session 7 – February 1
                                Interpretation
                    Case study 2: Resilient Floor Coverings

               Typical material compositions of the three studied products




PVC flooring                  Polyolefin flooring           Linoleum flooring
PVC                   40%     Limestone             55%     Wood powder            30%
Limestone             35%     Polyolefins           40%     Linseed oil            25%
Plasticizer: DEHP     20%     Pigments              5%      Limestone              20%
Pigments              5%                                    Jute                   10%
                                                            Colophony              5%
                                                            Cork                   5%
                                                            Pigments               5%


      Functional unit: Typical use of 20m2 of flooring over a period of 20 years


               Industrial Ecology – Winter 2006 – Session 7 – February 1
                          Interpretation
              Case study 2: Resilient Floor Coverings

                                               Water demand (cubic meter)
       Gross energy demand (MJ)
                                           2
3500
3000                                     1.5

2500                                       1
2000                                     0.5
1500                                       0
1000                                             PVC      Polyolefins Linoleum
500
  0
       PVC     Polyolefins Linoleum

       Non-renewable

       Renewable


         Industrial Ecology – Winter 2006 – Session 7 – February 1
          Interpretation: Case study 2: Resilient Floor Coverings
         Chemical waste (kg)                        Global warming potential CO2 eq
                                           400
8
6                                          300

4                                          200

2                                          100
0                                               0
        PVC       Polyolefins   Linoleum              PVC     Polyolefins   Linoleum

         Municipal waste (kg)                       Acidification potential (Mol H+)
80                                         50
                                           40
60
                                           30
40
                                           20
20                                         10
    0                                       0
        PVC        Polyolefins Linoleum              PVC     Polyolefins Linoleum

              Industrial Ecology – Winter 2006 – Session 7 – February 1
                         Interpretation
             Case study 2: Resilient Floor Coverings


In their study Günther & Langowski conclude that concerning
the different flooring options, there is no material specific ranking
possible, for ‘best’ or ‘worst’ environmental performance.

Does this follow conclusively from the presented results?




Discuss Günther & Langowski’s choice of impact categories.
How does it compare to the categories of the UNEP/SETAC
Life Cycle Initiative?
How appropriate is the choice given the subject of the study?



       Industrial Ecology – Winter 2006 – Session 7 – February 1
                               Interpretation
                   Case study 2: Resilient Floor Coverings

The study of Günther & Langowski received the following critique from Finnveden in
a letter to the Int. J. of LCA, 2(4), pp.185-186, 1997:
• Impact categories human toxicity and ecotoxicity are missing but critical to fully
  assess PVC.
• Based on the considered impact categories (Gross energy, water demand,
  chemical waste, solid waste, global warming potential and acidification potential)
  Polyolefins seem the better alternative to PVC.
• PVC production can be based on olefins but has the additional toxicological
  impacts of the production, use and disposal of chlorine, stabilizers and plasticizers.
• Apart from CO2eq emissions, Linoleum also seems to be a better alternative
 to PVC. In the Günther & Langowski study the GWP of Linoleum comes largely
 from their model of linoleum landfilling and anaerobic decomposition. This model is
 very sensitive to assumptions about waste management practices.
• The use of pesticides in the life cycle of Linoleum makes a toxicological
  comparison with PVC difficult.


             Industrial Ecology – Winter 2006 – Session 7 – February 1

				
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