A measure of aggregate environmental impact

Costs in Euros, environmental impact in …?

In the eco-efficiency approach, are defined quantitatively in monetary units, while environmental aspects are defined as determined according to a defined model which combines the individual environmental impacts and types of resource consumption.

Progress in Eco-Efficiency Analysis was impeded for a long time by the circumstance that no quantitative measure was defined for environmental impacts. Curiously, this was and continues to be due above all to the ISO 14040 LCA standard, because this standard rejects an aggregation of individual environmental impacts throughout product life cycles as overall environmental impact if different product alternatives are being compared and the findings are to be published.

To perform an Eco-Efficiency Analysis, however, it is essential to express environmental impact in one measure. It would otherwise only be possible to state individual efficiencies (cf. Figure 6: EcoGrade and Figure 11: Individual efficiencies and eco-efficiency).

Aggregation with EcoGrade

A range of different assessment models using an overall environmental indicator can be used for the aggregation of individual environmental impacts. PROSA uses the EcoGrade assessment framework developed by the Öko-Institut, which expresses the level of environmental impact in environmental target impact points (Umwelt-Ziel-Belastungs-Punkte, UZBP). Where required, other assessment frameworks can also be used as an alternative or supplement and to compare findings.

While the monetary unit (Euro, Dollar or others) expressing costs is a readily understandable unit, this does not apply to aggregate environmental impact (regardless of the framework used to determine it).

When communicating findings, it should be examined whether there is an individual parameter among the alternatives studied that largely follows the overall environmental impact (this often applies to energy consumption or CO2 emissions!). If this is the case, it would then be appropriate to express findings in terms of energy efficiency or CO2 efficiency.

Presentation of findings

The findings of the LCA and Life-Cycle Costing sub-studies should be presented in both numerical and graphic form for the individual alternatives (cf. table and figures on the washing machine case study). Eco-efficiency captures the ratio between goal attainment and input, whereby the goal is a dual one: to maintain equivalent utility for all alternatives studied, and to reduce environmental impacts to a minimum. Accordingly, the comparison of two alternatives places the reduction in environmental impact (expressed in environmental impact units) in relation to the additional input or additional cost (expressed in monetary units). The larger this value, the more eco-efficient the alternative is.