Environmental assessment of products: The ranges of the societal preferences method

The evaluation of product alternatives in Life Cycle Analysis (LCA) is a critical step on the basis of results as related to their impact category data. Decisions involving several environmental issues are hardly ever straightforward, since one alternative only seldom clearly dominates the others in all aspects. More often, one alternative scores better on some environmental issues and worse on others. A combination of impact data and preferences is then required for evaluation. This can be done using evaluation methods based on fixed societal preferences. However, by applying different evaluation methods to the same data, different 'best' alternatives may be chosen. This reduces the credibility of LCA results. Instead of fixed societal preferences an approach has been developed which uses consensus- oriented ranges of societal values for specifying the ranking of the overall environmental attractiveness of alternatives. These ranges may indicate both the uncertainty of decision-makers and the shifting of societal values, e.g. as related to the dynamics of knowledge of environmental problem areas. In this article, an approach is proposed which combines environmental data and uncertain societal values to form a clear statement on alternatives regarding their overall damage. By using a full set of potentially relevant societal preferences, a merely coincidental selection of the best product alternative is ruled out. A step-by-step procedure, narrowing down the feasible range of societal preferences, has been developed. The approach is illustrated using a case study of TV-housing concepts and a survey.