1 Background, aim, and scope
2 Materials and methods
2.1 Specifying uncertainty
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Parameter uncertainty: uncertainty in observed or measured values used as input to a model
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Model uncertainty: uncertainty about the way the interaction between technosphere and biosphere has to be modeled leads to uncertainty
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Scenario uncertainty: relates to choices made in constructing scenarios. Typical choices include choice of impact assessment method and allocation
2.2 Comparison situation 1
Life cycle stage (label) | Scenario | Intrapractitioner | Multipractitioner comparison using product category rules | Multipractitioner comparison using ISO 14044 |
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Comparison situation 1 | Comparison situation 2 | Comparison situation 3 | ||
Use phase (wash) | Wash temperature | Fixed (at 40°C) | Fixed (at 40°C) | Switch 30°C or 40°C |
g CO2 eq emissions electricity generation | Fixed (at 570 g CO2 eq/kWh) | Fixed (at 570 g CO2 eq/kWh) | Variable | |
Efficiency washing machine | Fixed (at 0.0277 kWh/°C wash) | A-class washing machine—variable | A-class washing machine—variable | |
Formula manufacturing (manufactE) | Emissions during product formulation | Variable | Variable | Variable |
Chemical manufacturing (ingrAm, ingrE) | Amount of ingredients in detergent | Variable | Variable | Variable |
g CO2 eq emissions ingredient production | Fixed (according to TEAM database information) | Variable | Variable | |
Packaging production (packE, packAm) | g CO2 eq emissions packaging production | Fixed (according to TEAM database information) | Variable | Variable |
Amount of package material | Variable | Variable | Variable | |
Transport (trAm, trE) | Transport distances raw materials | Variable | Variable | Variable |
Transport distances finished product | Variable | Variable | Variable | |
Emissions during transport | Fixed (according to TEAM database information) | Variable | Variable | |
Packaging waste treatment (packwasteAm, packwasteE) | Fractions of waste going to recycling and final waste treatment | Variable | Variable | Switch: include or exclude package waste treatment |
Emissions during waste treatment package material | Fixed (according to TEAM database information) | Variable | Variable | |
Wastewater treatment (thod, wwtp) | Theoretical oxygen demand chemicals | Variable | Variable | Variable |
Wastewater treatment plant emissions | Fixed (assuming full degradation of organic chemicals) | Variable | Switch: include or exclude waste water treatment |
2.3 Comparison situation 2
2.4 Comparison situation 3
2.5 Sources for uncertainty information
2.6 Carbon footprint model for laundry detergents
2.7 Stepwise sensitivity and uncertainty analysis
2.8 Sensitivity analysis
2.9 Refined uncertainty specification in the comparison situations
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Collecting specific information about uncertainty for most influential parameters
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Assessing the suitability of the distribution function (although fitting distribution functions was often impossible due to limited data availability)
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Assessing possible existence of correlation coefficients between the most influential parameters
2.10 Uncertainty analysis
2.11 Subjective versus analytical approach
3 Results
Parameter | Unit | Comparison situation 1 | Comparison situation 2 | Comparison situation 3 |
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∆CF deterministic | g CO2 eq/wash | 73 | 73 | 82 |
Mean | g CO2 eq/wash | 73 | 73 | 81 |
SD | g CO2 eq/wash | 4 | 44 | 114 |
10th percentile | g CO2 eq/wash | 68 | 16 | −63 |
90th percentile | g CO2 eq/wash | 78 | 130 | 226 |
Min | g CO2 eq/wash | 61 | −75 | −340 |
Max | g CO2 eq/wash | 89 | 226 | 483 |
CF ul > CF cp | % | 0 | 5 | 23 |