Applying multi-criteria decision analysis to combine life cycle assessment with circularity indicators

Monitoring the transition to a circular economy requires not only the measurement of circularity but also of environmental impacts, which often present trade-offs due to different perspectives when assessing a product. This article proposes a novel approach, named ECI-MCDA, to combine circularity and Life-Cycle Assessment (LCA) indicators via Multi-Criteria Decision Analysis (MCDA) non-compensatory methods (Electre I and Electre TRI). The proposed approach includes a clustering analysis to inform the choice of circularity indicators, and a robustness analysis to assess the influence of the MCDA parameters. The ECI-MCDA approach is applied to a multifunctional building sandwich-block (CleanTechBlock) composed of a thermal insulation layer incorporating over 90% recycled glass. The environmental performance and circularity of CleanTechBlock is assessed for different end-of-life (EoL) scenarios, including reuse, closed- and open-loop recycling. The ECI-MCDA approach has demonstrated its efficacy in handling divergent results between circularity and environmental performance, identifying an alternative that addresses both perspectives. Additionally, the proposed approach shows the potential to support decision-making to improve circularity and environmental performance, thereby promoting the eco-design of products.