Resource modelling in a circular economy context

Abstract: The concept of the circular economy (CE) is increasingly suggested as a means of reducing environmental impacts and resource use of production and consumption through CE strategies like reuse, remanufacturing, and recycling. However, an increase in “circularity” does not guarantee an improvement in the use of resources over the lifecycle of a product. Transitions towards a more circular economy therefore need to be supported by quantitative assessments that can guide companies and policymakers in choosing appropriate strategies to implement. However, different methods vary in terms of their scope and focus, and therefore convey different types of information about the system investigated. This thesis aims to contribute towards improved knowledge about a number of methods that can evaluate how CE strategies affect resource use, specifically focusing on CE indicators and dynamic material flow analysis (MFA). The work presented builds on two studies. Article I is a review and mapping of the flows and processes that CE indicators capture in the product lifecycle. The indicators are also applied to a wide number of cases to determine how the indicators differ and to identify their potential limitations. In article II a dynamic MFA model is developed and applied to a multiple reuse and recycling case of lithium-ion batteries. The study examines how this circular solution could affect raw material and battery flows over time. Finally, the two studies are synthesised into a method comparison of CE indicators and dynamic MFA. The comparison focuses on similarities and differences between the methods with regards to the object of study, how temporal aspects are represented, system boundaries, and the type of results provided. While CE indicators provide information on variations of resource use over the product lifecycle, dynamic MFA informs on how CE strategies can affect stocks and flows of products and materials over time. Amongst other things, the results emphasise the importance of capturing the temporal dynamics of material flows when evaluating CE strategies, e.g. how the availability of secondary resources could change over time or assessing how a transition towards a more circular economy can play out over time.