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An environmental LCA evaluates a product’s environmental impact over the course of its entire life from its manufacture through its use and disposal.  An LCA is a detailed assessment covering the consumption of all raw materials, chemicals and energy and the emissions to land, air and water of waste. The breadth of an LCA allows an assessment to be made about how a product’s overall environmental impact can be reduced.

The report assessed the six types of mercury-containing lamps commonly used in New Zealand’s residential, commercial and industrial sectors. These include:

  1. linear fluorescent (LFL)
  2. compact fluorescent: external ballast (CFLe)
  3. compact fluorescent: integral ballast (CFLi)
  4. high pressure sodium (HPS)
  5. metal halide (MH)
  6. mercury vapour (MV).

The impacts for each lamp were assessed against a number of environmental impact categories, including: global warming potential; ecotoxicity; human toxicity; resource depletion, stratospheric ozone depletion, photo-oxidant formation (smog); acidification and eutrophication.

The primary human toxicity impacts from mercury-containing lamps results from emissions from the generation of electricity to power them in the use phase.  The end-of-life impact of mercury-containing lamps was assessed to be less than one per cent of the total life-cycle impact. 

When assessing end-of-life impact alone (excluding manufacture and lamp use), the effect of mercury in the end-of-life phase is significant. Mercury from landfills was found to represent 25 per cent of human toxicity impacts for CFLs and 90 per cent for industrial lamps.

Reducing the impact of lamps in any life-cycle phase will yield benefits. Improving lamp efficiency, for example, will reduce the environmental impacts from lamps due to lower electricity use. Increasing the rate of recycling of mercury-containing lamps will enhance end-of-life environmental performance, and will result in a reduction of whole-life human toxicity impacts by about 1.5 per cent. 

The report will be used to inform the evidence base for discussions with stakeholders on policy options. It is part of a series of three reports to inform the development of a potential industry-led, voluntary product stewardship scheme specifically for New Zealand.

Electricity consumption is not one of the environmental impacts assessed but electricity consumption is an activity that contributes to a number of environmental impacts that are assessed such as global warming potential, resource depletion and ecotoxicity. In conducting an LCA, all product inputs and outputs are considered in order to provide a total picture of the impacts on the environment.  When comparing different lamps, one which uses less electricity will have lower overall environmental impacts due to reduced electricity use. For this study, a typical New Zealand generation mix of renewable and fossil-fuel generation was used.