Development of Life Cycle Impact Assessment Weighting Methodology for Japan

Weighting Methodology Based on the Distance-to-Target Method

Abstract

Life cycle assessment (LCA) has received much attention as an effective tool to evaluate the environmental burden of a product or service during its life cycle. Many LCA case studies have been carried out in Japan. However, impact assessment has been seldom conducted. Some of the reasons are that impact assessment has not been well investigated and few weighting methodologies practicable for Japan have so far been developed. In this work, development of life cycle impact assessment weighting methodology for Japan basedon the distance-to-target principle has been carried out. The methodology hastransparent characteristics and basically follows the SETAC ‘Code of Practice’: classification, characterization, normalization and weighting. Normalization values were estimated for 6 impact categories. Weighting factors for global warming and depletion of stratospheric ozone were derived from the deviation of annual emissions from authorized targets. In local impact categories, classification and characterization are not carried out; each substanceis weighted directly with the local normalization value and weighting factor. Site-specific differences in indicator points were shown, based on calculations using life cycle inventories for electricity distributed by the electric power companies in Japan.