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Highlights • Methodological advancement of metrics for circular economy at product level. • Multi Criteria Decision Analysis used to obtain better decision support. • Proposal to couple material circularity indicators and life cycle based-indicators. • Coupling performed via TOPSIS (Technique for Order by Similarity to Ideal Solution). • Illustrative case study for beer packaging used to validate the proposal. Abstract The debate on the identification of the most suited metrics for circular economy (CE) is open, no consensus has been reached yet on what CE indicators at product level should measure, which creates a subjective methodological framework for assessing CE strategies. In this study, we demonstrate that by coupling different types of indicators via Multi Criteria Decision Analysis (MCDA) it is possible to deal with conflicting situations where the selection of the best alternative can be biased by the choice of the metric. We use a beer packaging case, by simulating a situation where a company is interested in comparing the performances of different packaging from a CE perspective. We consider eight different beer packaging alternatives in two geographical contexts (United Kingdom and India). Two sets of indicators are coupled via MCDA: i) material circularity based- indicators, namely Material Reutilization Score and Material Circularity Indicator, and ii) a selection of life cycle based- indicators relevant for beer, i.e. climate change, abiotic resource depletion, acidification, particulate matter and water consumption. The results obtained by the application of the TOPSIS (Technique for Order by Similarity to Ideal Solution) method show that the different sets of indicators can be integrated and conflicts among them can be resolved. Overall, the application of different weighting scenarios does not change the ranking of the alternatives, thus confirming that the results are stable. Therefore, our proposal of coupling material circularity indicators with LCA indicators via MCDA can advance the assessment of CE strategies at the product level. [ABSTRACT FROM AUTHOR]

This study investigates the prevailing practice of obtaining single scores in life cycle assessment (LCA) and identifies potential lacunas in impact assessment methodology related to the results of aggregation into endpoints and single scores. In order to conduct this investigation, a detailed approach was adopted to facilitate identification of three main problems related to the single-score calculation approach. The prevailing ReCiPe single-score calculation method does not account for either the effect of so-called dominating alternatives (i.e., alternatives having high values across all endpoints) or the interdependency of the indicators being aggregated. It was also found that the simple linear weighted sum method, presently used for obtaining single scores, is not capable of accounting for the effect of weighting schemes and thus cannot realistically represent stakeholders' perspectives. Finally, we propose a distance-based multiple attribute decision-making method for use in obtaining single scores. This method was found to be more suitable, given that it takes into account the weighting schemes and types of indicators in the process of estimating single scores. The new single-score calculation method proposed here is considered ideal for environmental decision-making problems in the context of life cycle sustainability assessment. Thus, it is also ideal for situations in which more-complex decision-making situations will emerge by combining LCA indicators (midpoints or endpoints) with other indicators representing the performance of a system from economic and social perspectives. [ABSTRACT FROM AUTHOR]

This work looks at coupling Life cycle assessment (LCA) with a dynamic inventory and multiple criteria decision analysis (MCDA) to improve the validity and reliability of single score results for complex systems. This is done using the case study of a representative Danish single family home over the service life of the building. This case study uses both the established and the coupled MCDA assessment methods to quantify and assess the balance of impacts between the production of mineral wool insulation versus the production of space heat. The use of TOPSIS method for calculating single scores is proposed as an alternative to the ReCiPe single score impact assessment method. Based on the single score impact values obtained from both of these methods, various insulation levels are ranked to determine an ideal insulation level and gauge the effectiveness of environmental impact reduction measures in current Danish building regulations. Using a comparison of the results from the two methods, a preferred choice of impact assessment method is determined. The findings show that if the midpoint impacts for a particular scenario are strongly correlated with a climate change impact indicator, it does not matter which impact assessment is applied. However, for the scenarios where other impact categories vary inversely or independently from the climate change impact indicator, such as with renewable energy production, there is need for a more unconventional method, such as the TOPSIS method, for calculating single score impacts. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of selecting the most sustainable stormwater management alternative in developing countries in a dense urban context. Firstly, suitable Low Impact Development (LID) stormwater management measures for dense urban areas in developing countries were identified based on critical review of literature. Alternatives have been formulated as varying percentages (degree of adoption) of these suitable measures to manage the stormwater sustainably. Further, a novel decision-making framework is developed which generates the hierarchy for selection of the most sustainable stormwater management alternative. Four main criteria (technical, economic, environmental and social) comprising three quantitative and eight qualitative indicators have been used for evaluating seven alternatives. The regional and local societal priorities are captured through criteria-weightings and are translated into a decision-making methodology. Experts' opinions have been included using Analytical Hierarchy Process (AHP). One of the most widely used Multiple Attribute Decision-Making (MADM) method, TOPSIS, is used to rank the alternatives and to identify the most sustainable alternatives. Various scenarios to represent different stakeholders' perspectives have been articulated. Alternative with medium level of cost implication and satisfactory level of performance is chosen by the decision making method in most of the scenarios. The proposed decision making approach can be used for selecting sustainable stormwater management options in densely populated areas of developing countries. [ABSTRACT FROM AUTHOR]