The Waste and Resource Assessment Tool for the Environment (WRATE) is a life cycle assessment tool specifically developed by the Environment Agency to aid Local Authority decision making in the MSW management sector. WIDP recommends that the WRATE tool be used in assessing the environmental impacts of the options appraised at the OBC stage.16
The use of WRATE requires that certain input parameters (e.g. tonnage processed, waste composition) are defined and a technology or combination of technologies is selected. The WRATE data set includes thirty two technology choices (see Appendix 1) for which the output parameters are defined. Where a technology or system combination is proposed that does not match an existing data set within WRATE it is possible to create a new data set to model the system. During the options appraisal for the MWMS and OBC it should be possible to use the existing data sets with little or no modification to model the environmental impacts.
WRATE collates the input and output data and reports on a set of life cycle environmental impacts. There are six key impacts (reported by WRATE) that the Authority should include as part of its assessment of the environmental performance of options:
• Greenhouse gas emissions (GGE);
• Emissions contributing to air acidification;
• Emissions contributing to eutrophication;
• Emissions contributing to aquatic ecotoxicity;
• Resource depletion; and
• Human health toxicity.
Defra's recommended approach is that the impact of GGE should be converted into a financial impact and included within the FEC of each option.17 This requires the evaluation of the WRATE outputs to disregard the GGE emissions. These will still be taken into account but within the cost element of the evaluation. Details of the recommended methodology for evaluating GGE are set in full in Appendix 4.
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16 There are three specific occasions in the waste development process when the WRATE tool should be used:
• At options appraisal for developing the MWMS;
• At options appraisal for developing the OBC; and
• At the assessment of outline solutions submitted by bidders in the procurement process.
17 See Defra ' s guidance note on the Social Cost of Carbon for a more detailed explanation of why this is the recommended approach. This guidance is available at: http://www.defra.gov.uk/environment/climatechange/research/carboncost/pdf/HowtouseSPC.pdf