Distribution of environmental performance in life cycle assessments—implications for environmental benchmarking
Purpose Life cycle assessment (LCA) is considered a robust method to analyse the environmental impacts of products and is used in public and private market applications such as Green Public Procurement (GPP) and Environmental Management Systems (EMS). Despite the usefulness of the methodology, difficulties exist with the interpretation of LCA results. The use of benchmarks can facilitate this process, but there is yet little research on the definition of environmental benchmarks. The aim of this paper is to analyse the distribution of environmental performance used for the definition of the benchmark and how it effects the use in selected product categories. Method LCA results from 54 Environmental Product Declarations (EPDs) for insulation materials and 49 EPDs for bakery products are tested for their distribution. The outcome from the statistical analysis is used to compare and evaluate three calculation methods for a benchmark. Results and discussion The results of the study show that distributions and mid- and end-points of environmental performances of the studied indicators differ significantly for the two product categories. While some indicators for bakery products were closer to a normal distribution, most of the indicators are not normally distributed. This is reflected in the comparison of the chosen calculation methods for a benchmark, which showed that the distribution of the data affects the classification of the benchmark as well as the position of values on the benchmark. Conclusion The results emphasise that analysis of further product groups and the associated distribution of the environmental performance is needed to understand the implications of calculation methods on a benchmark. The availability of comparatively large datasets in a common structure is crucial for these analyses and can be facilitated through the digitalisation of LCA- and EPD-information. Furthermore, more research is needed on the communication formats for different benchmarking options, which must be applied for the different intended audiences to be effective.