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4 Inventory Analysis

Section 4 presents the life cycle inventory results for the six lamps types assessed, for the following:

  • by life cycle stage for baseline scenario (i.e. 9% recovery and recycling);
  • for whole life comparing different recovery and recycling rates (Baseline 9%, Scenario 1: 50%, Scenario 2: 80% and Scenario 3: 0%); and
  • for end-of-life comparing different recovery and recycling rates (Baseline 9%, Scenario 1: 50%, Scenario 2: 80% and Scenario 3: 0%).

The inventories generated provide data on hundreds of internal and elemental flows for each lamp type.   Appendix C shows the results Tables for the inventory analysis.  The sections below provide a description and interpretation of these inventory results.

4.1 Inventory Data by Life Cycle Stage

Table  to Table C1f in Appendix C present the inventory results by life cycle stage for each of the lamps assessed in the study. 

The results indicate that in general the use phase dominates the inventory results across the life cycle.  For example, for carbon dioxide emissions to air or non-renewable energy, the use phase accounts for around 90% to 99% of the life cycle, while the manufacturing phase accounts for around 0.5% to 10%.  As would be expected, the lamps that have a higher wattage (HPS, MH and MV) show higher consumptions in the use phase compared to the lower wattage lamps (LFL, CFLe and CFLi).

The reason for the relatively higher inventory data for CFLi lamps in the manufacturing phase, compared to other lamp types, is due to the electronics incorporated into the lamp unit.

The results in relation to mass of mercury emissions to air, water and land show that emissions are very small in total mass, with the majority of emission being to land, followed by emission to water.  Emissions to air are relatively minimal relative to land and to water.  Of emissions to land and water, the disposal phase produces the majority of emissions (around 50% to 80%) followed by the use phase.   For CFLi lamps the manufacturing phase contains a higher amount of mercury emissions, compared to other lamps types, due to the electronics incorporated into the lamp unit.

Please refer to Section 5 for details of the scale of environmental impacts of the mercury emissions.  
Table 6 shows an example set of result for a CFLi lamp.

Table 6 Life Cycle Inventory – Baseline: 9% Recycling – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation)

  Unit Manufacture Import and distribution Retail and use Waste disposal NZ Recycling Displaced material benefits Total
Total mercury use in lamp manufacture – internal flow mg 5.0 0.0 0.0 0.0 0.0 0.0 5.0
Coal – resource kg 17.6 0.0 83.4 0.0 0.0 0.0 101.0
Natural gas – resource m3 3.4 0.0 133.2 0.0 0.0 0.0 136.6
Oil  – resource m3 1.5 0.1 2.5 0.0 0.0 0.0 4.1
CO2 (fossil) to air kg 40.9 0.2 415.4 0.0 0.0 -0.1 456.4
CO to air kg 0.0 0.0 0.1 0.0 0.0 0.0 0.2
SOx to air kg 0.4 0.0 1.0 0.0 0.0 0.0 1.4
NOx species to air kg 0.1 0.0 0.9 0.0 0.0 0.0 1.1
N2O to air kg 0.0 0.0 0.0 0.0 0.0 0.0 0.0
CH4 to air kg 0.2 0.0 1.8 0.0 0.0 0.0 1.9
VOC to air kg 0.0 0.0 0.2 0.0 0.0 0.0 0.2
Particulates to air kg 0.1 0.0 0.3 0.0 0.0 0.0 0.4
Hg to air mg 0.00000002 0.00000000 0.00000000 0.00000000 0.00000000 0.00000000 0.00000002
Hg to water mg 0.00000057 0.00000000 0.00000015 0.00000078 0.00000000 -0.00000001 0.00000149
Hg to land mg 0.00000000 0.00000000 0.00000001 0.00000182 0.00000000 0.00000000 0.00000183
Energy – Non renewable Mj 600.8 2.9 6,839.1 0.4 0.7 -3.1 7,440.8
Energy – Renewable Mj 33.7 0.0 756.2 0.0 0.1 -0.2 789.9

Note: a negative number represents an environmental benefit

4.2 Inventory Data for Whole Life

Table C2a to Table C2f in Appendix C presents the whole-life inventory results for each of the lamps assessed in the LCA for the following scenarios:

  • Baseline performance for 2007: 9% recovery and recycling;
  • Scenario 1: 50% recovery and recycling;
  • Scenario 2: 80% recovery and recycling; and 
  • Scenario 3: 100% landfill.

The results indicate that environmental benefit arises from increasing the recycling levels for all lamp types.  However, the benefits achieved are very small across the whole life cycle.  For example, for carbon dioxide emissions to air or non-renewable energy, an increase in recycling rate from 9% to 80% provides a benefit of around 0.25% of the total life cycle. 

Please refer to Section 5 for details of the scale of environmental impacts of the mercury emissions.  
Table 7 shows an example set of results for a CFLi lamp.

Table 7 Life Cycle Inventory – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation)

 

Unit

Baseline: 9% recovery and recycling

Scenario 1: 50% recovery and recycling

Scenario 2: 80% recovery and recycling

Scenario 3: 100% landfill

Total mercury use in lamp manufacture – internal flow mg 5.0 5.0 5.0 5.0
Coal – resource kg 101.0 101.0 100.9 101.0
Natural gas – resource m3 136.6 136.5 136.4 136.7
Oil  – resource m3 4.1 4.0 3.9 4.1
CO2 (fossil) to air kg 456.4 456.0 455.8 456.5
CO to air kg 0.2 0.2 0.2 0.2
SOx to air kg 1.4 1.4 1.3 1.4
NOx species to air kg 1.1 1.1 1.1 1.1
N2O to air kg 0.0 0.0 0.0 0.0
CH4 to air kg 1.9 1.9 1.9 1.9
VOC to air kg 0.2 0.2 0.2 0.2
Particulates to air kg 0.4 0.4 0.4 0.4
Hg to air mg 0.00000002 0.00000001 0.00000000 0.00000002
Hg to water mg 0.00000149 0.00000111 0.00000083 0.00000158
Hg to land mg 0.00000183 0.00000101 0.00000042 0.00000201
Energy – Non renewable Mj 7,440.8 7,429.9 7,421.9 7,443.2
Energy – Renewable Mj 789.9 789.6 789.5 789.9

4.3 Inventory Data for End-of-Life Phase

Table C3a to Table C3f in Appendix C presents the end-of-life inventory results for each of the lamps assessed in the LCA for the following scenarios:

  • Baseline performance for 2007: 9% recovery and recycling;
  • Scenario 1: 50% recovery and recycling;
  • Scenario 2: 80% recovery and recycling; and 
  • Scenario 3: 100% landfill.

The results show the environmental benefits from the end-of-life stage increase significantly with increasing recovery and recycling levels for all lamp types.  For example, for a CFLi lamp, the carbon dioxide emissions benefit increases by ten-fold (from a saving of -0.06kg CO2 to a saving of -0.75kg CO2) by increasing the recovery and recycling rate from 9% to 80%.  This similarly occurs for all other lamps types.

Please refer to Section 5 for details of the scale of environmental impacts of the mercury emissions.  
Table 8 shows an example set of result for a CFLi lamp.

Table 8 Life Cycle Inventory – End-of-Life Only – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation)

  Unit Baseline: 9% recovery and recycling Scenario 1: 50% recovery and recycling Scenario 2: 80% recovery and recycling Scenario 3: 100% landfill
Total mercury use in lamp manufacture – internal flow mg 0.00 0.00 0.00 0.00
Coal – resource kg 0.00 -0.02 -0.03 0.00
Natural gas – resource m3 -0.03 -0.16 -0.25 0.00
Oil  – resource m3 -0.01 -0.11 -0.19 0.01
CO2 (fossil) to air kg -0.06 -0.46 -0.75 0.03
CO to air kg 0.00 0.00 0.00 0.00
SOx to air kg 0.00 -0.02 -0.04 0.00
NOx species to air kg 0.00 0.00 0.00 0.00
N2O to air kg 0.00 0.00 0.00 0.00
CH4 to air kg 0.00 0.00 -0.01 0.00
VOC to air kg 0.00 0.00 0.00 0.00
Particulates to air kg 0.00 0.00 0.00 0.00
Hg to air mg 0.00000000 -0.00000001 -0.00000002 0.00000000
Hg to water mg 0.00000077 0.00000039 0.00000011 0.00000086
Hg to land mg 0.00000182 0.00000100 0.00000041 0.00000200
Energy – Non renewable Mj -2.01 -12.92 -20.91 0.39
Energy – Renewable Mj -0.05 -0.26 -0.41 0.00

Note: a negative number represents an environmental benefit.