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6. Interpretation

Section 6 contains the interpretation and sensitivity analysis which considers lamp performance and addresses key assumptions within the study in order to test the robustness of the conclusions and recommendations suggested by the results of the study.
The following analyses have been assessed:

  • impact of assumed lifetime of the lamps – ± 50% lifetime;
  • impacts of assumed power rating of the lamps, accounting for potential increases in energy usage from lamp warm-up – +0.5%;
  • impacts of improved energy efficiency in the use phase – +10% efficiency;
  • impacts of closed loop recycling;
  • impacts of attributing offset benefits to avoided materials from lamp recycling operations;
  • potential impacts of packaging and fittings.

No significant cut-off criteria have been applied to the study and are therefore not tested in the sensitivity analysis.

The results are presented only for the CFLi lamp in the report, although discussion is provided as to implications for the other lamp types.

Further details of these sensitivity analyses and assumptions made can be found in Appendix B, Section B.11. 

6.1 Impact of Assumed Lamp Lifetime

The sensitivity analysis has assessed the potential implications of both extended and reduced lifetime of ± 50% for each lamp type.  The results are presented for the baseline scenario of 9% recycling for a CFLi lamp over 100,000 hours operation in Figure 21.

The results clearly indicate that significant benefits arise from extended product life, particularly in relation to human toxicity and ecotoxicity impact indicators.  These benefits primarily arise due to the reduced requirements for manufacturing the product, as well as reduced waste disposal requirements.  As would be expected, the opposite is true for reduced lifetime. 

It should be noted that this is a theoretical sensitivity analysis and it does not account for the changes in lamp design or technical feasibility.  Lamp manufacturers have indicated (Philips, 2009) that increased life requires increased mercury levels in the lamp.  However, when considering the impacts of human toxicity and ecotoxicity the benefits of increased lifetime is likely to outweigh the impacts associated with increased mercury levels. 

Figure 21 Life Cycle Impacts – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – ± 50% Lifetime

 

Illustrated as a bar-graph into 10 impact categories covering three baselines: maximum life, minimum life and typical life.

Environmental benefits are achieved across each of the 10 impact categories for the theoretical maximum lamp lifetime in comparison to the typical life for baseline results.  As lifetime is increased the environmental benefits increase.  For example, the highest environmental benefit is achieved for maximum lifetime, compared to typical lifetime, for fresh water aquatic ecotoxicity at 57% then terrestrial ecotoxicity at 51%.

6.2 Impacts of Lamp Warm-Up and Impacts of Improved Energy Efficiency in the Use Phase

This sensitivity has assessed, individually, the consequence of reduced energy efficiency from potential warm-up effects, and a 10% increase in the use phase energy efficiency.  The results are presented for the baseline scenario of 9% recycling for a CFLi lamp over 100,000 hours operation in Figure 22.

In relation to warm-up effect these are negligible across all impact indicators for the results presented.  The impacts increase, marginally, due to the higher energy demand in the use phase. 

Due to the significance of the use phase, for all lamp types, the efficiency change is reflected directly in the impact reductions witnessed. This is especially the case for abiotic resource depletion, acidification, eutrophication, global warming potential and human toxicity, where a 10% improvement in energy efficiency results in a nearly matched improvement for these indicators (of around 8% to 9%).  Similarly, other impacts indicators reduce but to a slightly lesser extent (of around 2% to 4%).

It should be noted increased energy efficiency is a theoretical sensitivity analysis and it does not account for the changes in lamp design or technical feasibility.   

Figure 22  Life Cycle Impacts – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – +0.5% increase in energy usage from lamp warm-up and improved energy efficiency in the use phase – +10% efficiency

 

Illustrated as a bar-graph into 10 impact categories covering three baseline scenarios for: warm-up, improved efficiency and typical efficiency.

For the baseline scenarios for warm-up and typical efficiency, the environmental benefits across all 10 categories was zero or negligible.

For improved efficiency, the environmental benefit across the 10 impact categories was between 3% and 10%, compared to the ‘typical’ scenario.


6.3 Impacts of Closed-Loop Recycling

Whole Life Results: Closed-Loop Recycling

Closed loop3 recycling has been appraised and includes the recycling process requirements, reduced virgin material requirement in lamp manufacture, and the additional oceanic transport of material and container back to place of manufacture.

The sensitivity compares the benefits of recycling and recovery of materials in a closed manner, versus material recycling and second use in Australia via open-loop4 recycling.

The results shown in Figure 23 indicate that there is no significant environmental benefit of closed-loop recycling compared to open-loop.  This is due to the recovered materials displacing the same quantities of virgin material in both open-loop and closed-loop recycling.  A difference arises due to the additional oceanic transport, for closed-loop recycling, back to the original place of manufacture. 

End-of-Life Results: Closed-Loop Recycling

The results for end-of-life only shown in Figure 24 indicate that closed loop recycling provides less benefit across all environmental impact indicators, although the results are not significantly different.  Closed-loop recycling results in greater impacts due to the additional oceanic transport to return materials back to the original place of manufacture, versus Melbourne, Australia, for the open-loop recycling.

Figure 23 Life Cycle Impacts – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – Closed Loop Recycling

 

Illustrated as a bar-graph into 10 impact categories covering two baseline scenarios for closed-loop and open-loop recycling.

For both baseline scenarios for closed-loop and open-loop, the difference in environmental impact benefits across all 10 categories was zero or negligible.

Figure 24  Life Cycle Impacts – End-of-Life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – Closed Loop Recycling

 

Illustrated as a bar-graph into 10 impact categories covering two baseline scenarios for closed-loop and open-loop recycling.

For the closed-loop baseline scenario, the environmental benefit across all impact categories was lower than for the open-loop baseline.

6.4 Impacts of Not Attributing Offset Benefits to Avoided Materials from Lamp Recycling and Recovery

Whole Life Results: Not Attributing Offset Benefits to Avoided Materials

The assumption that recovered materials will displace primary/virgin material production, on a weight for weight basis, is subject to some uncertainty.

As an extreme, the consequence of not expanding the system boundary and attributing an offset benefit to avoided primary material production is considered in this sensitivity analysis.

The results indicate, as shown in Figure 25, that the recycling route (without virgin material displacement), does not result in environmental benefit when compared to conventional disposal, with the exception of the terrestrial ecotoxicity impact categories.

The results indicate that the benefits of increased recycling and recovery are primarily driven by the benefits derived from avoided material production and of the reduced emissions resulting from avoided waste production. 

End-of-Life Results: Not Attributing Offset Benefits to Avoided Materials

When considering the end-of-life impacts only of not including the benefits of virgin material displacement the results indicate, as shown in Figure 26, that decreased levels of recycling significantly improve environmental performance.  This is primarily due to the reduced impacts associated with disposal phase. 

Figure 25 Life Cycle Impacts – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – No Benefit Attributed to Avoided Products

 

Illustrated as a bar-graph into 10 impact categories covering four situations:

  • baseline (%): no benefits
  • baseline (9%): with benefits
  • scenario 5 (80%): no benefits
  • scenario 5 (80%): with benefits.

The graph is a sensitivity analysis of the environmental impacts based on an assumption that recovered materials will displace primary/virgin material production.  This displacement generates an environmental benefit from avoiding the need to produce these materials.  The graph shows that the recycling route (without virgin material displacement), does not result in an environmental benefit when compared to conventional disposal, except for terrestrial ecotoxicity where for ‘scenario 5 (80%): no benefits’ and ‘scenario 5 (80%): with benefits’, where there are benefits of 16% and 30% respectively.

Figure 26 Life Cycle Impacts – End-of-Life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – No Benefit Attributed to Avoided Products

 

Illustrated as a bar-graph into 10 impact categories covering four situations:

  • baseline (%): no benefits
  • baseline (9%): with benefits
  • scenario 5 (80%): no benefits
  • Scenario 5 (80%): with benefits.

The graph is a sensitivity analysis of the end-of-life environmental impacts only based on an assumption that recovered materials will displace primary/virgin material production.  This displacement generates an environmental from avoiding the need to produce these materials.  The graph shows that the recycling route without virgin material displacement results in the highest environmental benefit across all 10 categories.

6.5 Potential Impacts of Packaging and Fitting

To test the original decision to exclude packaging and fittings, an estimate of their contribution has been made, based on secondary inventory data and estimates of weights.

The results of this sensitivity indicate, as shown in Figure 27, with the exception of human toxicity and fresh and marine water ecotoxicity, that the exclusion of these elements is insignificant.  The increased impacts for these indicators are linked to the emissions associated with the production of the raw materials, in particular aluminium, used to fabricate the fittings.  Packaging has a negligible effect.  Refer to Appendix D for further details.  A similar conclusion can be drawn for other lamp types.  However, the inclusion of packaging and fittings would not change the conclusions of this study, only the relative magnitude of the contributing elements to the toxicity impact categories.

Figure 27  Life Cycle Impacts – Whole life – Compact fluorescent lamps (CFLi) 20W: integral ballast (100,000 hours operation) – Impacts of Packaging and Fittings

 

S

  • baseline: without packaging and fitting
  • baseline: with packaging and fitting.

For abiotic depletion, acidification, eutrophication, global warming, ozone layer depletion, terrestrial ecotoxicity and photochemical oxidation the difference between both baseline scenarios is zero to 2% difference. 

For human toxicity, fresh water aquatic ecotoxicity and marine aquatic ecotoxicity the environmental impacts improved to between 15% and 25% for the baseline without packaging and fittings, compared to the scenario with these items included.

6.6 Summary of Interpretation

Section 6 contains the interpretation and sensitivity analysis which considers lamp performance and addresses key assumptions within the study.  The following analyses were assessed:

  • impact of assumed lifetime of the lamps – ± 50% lifetime;
  • impacts of assumed power rating of the lamps, accounting for potential increases in energy usage from lamp start-up – +0.5%;
  • impacts of improved energy efficiency in the use phase – +10% efficiency;
  • impacts of closed loop recycling;
  • impacts of attributing offset benefits to avoided materials from lamp recycling operations;
  • potential impacts of packaging and fittings.

No significant cut-off criteria have been applied to the study and are therefore not tested in the sensitivity analysis.

The results indicate that lamp performance parameters, such as lamp lifetime and energy efficiency, have a significant effect on the environmental performance across all lamp types.  An increase in lamp lifetime reduces production burdens and waste management and results in significant benefits.  Similarly, a reduction in energy consumption through higher lamp efficiency would reduce the use phase burdens significantly.

The results indicate that the benefits of increased recycling and recovery are primarily driven by the benefits derived from avoided material production and of the reduced emissions resulting from avoided waste production.  If zero benefit is attributed to avoided virgin materials then recycling does not result in an environmental benefit when compared to conventional disposal, with the exception of the terrestrial and fresh and marine water ecotoxicity impact categories.

An estimate has been made for the exclusion of packaging and fittings, which shows that this decision has a small effect on the overall results, with the exception of human toxicity and fresh and marine water ecotoxicity.  The increased impacts for these indicators are linked to the emissions associated with the production of the raw materials, in particular aluminium, used to fabricate the fittings.  Packaging has a negligible effect.  A similar conclusion can be drawn for other lamp types.  The inclusion of packaging and fittings would not change the conclusions of this study.

3. Closed-loop recycling can be generally defined as a recycling system in which a particular mass of material (possibly after upgrading) is remanufactured into the same product (e.g., aluminium from lamps returned back into use for aluminium into lamps).

4. Open-loop recycling can be generally defined recycling system in which a product made from one type of material is recycled into a different product.