Interpretation model EcoGrade

Interpretation models to capture aggregate environmental impact

LCA captures the most varied types of resource consumption (e.g. energy carriers, minerals, or water) and environmental impact in the form of impact categories (greenhouse gases, acidification, eutrophication etc.) and reports these in relation to a functional unit. For reasons of practicability and in order to allow integration into an overall assessment, it is purposeful to use interpretation models that allow integration of an aggregate expression of environmental impact. In doing so, expression of the data for the specific environmental impacts should always remain possible. An aggregate environmental indicator is particularly necessary when considering several or many products, and especially so when economic and social aspects are included. ISO Standards 14040/14044, however, prohibit such overall aggregation if different product alternatives are to be compared and published. This feature of the ISO standards stands in the way of practical application – in practice, aggregation to an expression of overall environmental impact must take place outside of the LCA in formal terms if the process is to conform to the standards.

EcoGrade interpretation framework

PROSA uses the EcoGrade environmental interpretation framework (cf. Figure 6). Most companies have their own environmental interpretation frameworks. Only few, such as BASF (Saling et al. 2002), make their use of these frameworks public. EcoGrade, the PROSA interpretation framework, can in principle be substituted by another framework, or complemented by another to provide a sensitivity analysis.

In EcoGrade, the various environmental impacts are weighted on the basis of socially agreed quantitative environmental targets (cf. in detail in Bunke et al. 2002 and Möller 2006). Each category of environmental impact is expressed in environmental target impact points (Umweltzielbelastungspunkt – UZBP) in accordance with its contribution to national or international environmental targets (depending upon the geographical scope of the analysis). Impact categories for which no quantitative environmental targets have yet been formulated are integrated within the overall result by means of a set percentage weighting. The higher the number of points, the greater is the environmental impact.

The environmental target impact points of the individual impact categories are added without any further weighting – it is assumed that all environmental targets agreed by societal consensus or legislative statute have equal weight. EcoGrade uses the environmental targets set by society and by the legislator to reflect societal evaluations – which is, after all, the frame of reference within which companies and product policy operate.