Comparison of ReCiPe 2016, ILCD 2011, CML-IA baseline and IMPACT 2002+ LCIA methods: a case study based on the electricity consumption mix in Europe

Abstract

Abstract Purpose The international standards ISO 14040 and ISO 14044 do not specify a single method for the performance of life cycle impact assessment (LCIA). As a result, many different LCIA methods have been developed and the choice between them is not always obvious. Therefore, the main aim of this research is to systematically compare the most commonly used multi-impact LCIA methods worldwide to support practitioners in confronting the question of how the choice of LCIA method affects the LCA results. Methods Four LCIA methods: ReCiPe 2016, ILCD 2011, CML-IA baseline and IMPACT 2002+ at the midpoint level were applied to compare the environmental profiles of the electricity consumption mix in the EU-27, Norway, Switzerland and the United Kingdom, taking into account the electricity consumption mix in individual countries. The results of the impact categories were converted into common metrics using unit conversion factors to allow the comparison of the results in absolute values across LCIA methods. Results and discussion In the LCA study, four common LCIA methods were compared across 12 defined midpoint areas of impacts. Results were consistent for climate change and ozone depletion, with the exception of the ReCiPe 2016 method, and acidification and eutrophication, with the exception of the IMPACT 2002+ method. Significant disparities were noted for ozone formation/respiratory organics, particulate matter/respiratory inorganics ecotoxicity and water consumption. The rankings of environmental profiles remained largely consistent across LCIA methods, with only a few exceptions concerning the following midpoint areas of impacts: ozone formation/respiratory organics, ecotoxicity and resource scarcity (minerals). Contribution analysis highlighted the crucial role of only a few key substances in each area. Conclusions The methodological choices during LCIA have significant implications for the characterisation results in absolute values, but lead, in most cases, to comparable conclusions on the ranking of environmental profiles of the electricity consumption mix in the EU-27, Norway, Switzerland and the United Kingdom. This results from large methodological discrepancies between LCIA methods, concerning, among others, the geographical differentiation (either the European or global context), the scope of the impact categories grouped into the same midpoint area of impacts (for instance eutrophication) and the contribution of specific environmental flows to a given result of the impact category. Consequently, the findings of this research underpin the importance of careful selection of the LCIA method and impact categories, following the goal and scope definition and unique attributes of each method.