BRJRDPSB

4106

25 mai 2021 13:03

25 mai 2021 13:06

Resources represent an important basis for the value creation of a society. With the economic growth of the past century, resource consumption reached an unprecedented scale, leading to severe environmental effects that made human activity a force of geologic importance. Given this background, large efforts are undertaken to transform the current production-consumption system that produces vast amounts of waste and emissions into a more Circular Economy (CE) that aims to preserve functionality and value of products, parts, and materials over a maximum period of time. However, measuring the transition towards a more circular system remains a challenge, especially in the light of the diversity of possible combinations of CE strategies that can be applied on the level of the product (e.g. product design, lifetime extension), component (e.g. remanufacturing, repair), or the material level (e.g. recycling). Employing the method of Statistical Entropy Analysis (SEA) that evaluates the concentration and dilution activities in a material flow system for single substances (elements and compounds), this thesis extends the method to a Multilevel SEA that considers additional material, component and product levels. As a result, the Multilevel SEA allows evaluating different combinations of CE strategies, quantifying the related efforts in terms of dilution and concentration activities performed in the system, while the extension of the method by a time-dynamic perspective allows assessing long term system transitions and related CE scenarios.In the first step, a structured analysis of 63 CE metrics is performed, leading to the identification of methodology clusters and related assessment perspectives. Applying the method of Multiple Correspondence Analysis (MCA), the metrics are structured in relation to each other as well as to the 24 assessment perspectives that are relevant to the CE, such as the availability of stocks, retention of products, parts and materials, the potential for recycling and recycling efficiency. Further, the MCA results are employed to assess how the different CE perspectives are associated with each other, and what CE perspectives are most commonly assessed in combination. The analysis identifies main metric clusters, including gaps and potentials to integrate CE perspectives or complementary CE metrics. Thereby, the results provide guidance for the development of CE metrics, which has also been considered to develop the SEA method further.In the second step, the SEA method is extended to the Multilevel SEA method that allows considering information on the product, component and material levels. The method is demonstrated on a case example of a simplified vehicle life cycle. The case example serves as a demonstrator to provide insights into how the method can identify critical stages of resource and functionality losses. Moreover, it demonstrates how different CE strategies, on their own or in combination, contribute to a system performance that can be measured as a distance to an ideal system state that preserves functionality on the highest level possible. Based on the results, a framework for resource effectiveness is derived in which diluting and concentrating effects of CE strategies are quantified and which allows to relate a variety of systems to a resource-effective system that maintains the product functionality over a maximum period of time, with minimal efforts that are measured in terms of changes of statistical entropy. In the third step, the Multilevel SEA method is extended by a time dimension and is applied to a more complex case study of a generic European automotive system. For the consideration of the time dimension, the method is applied in combination with a stock-driven model and a material flow analysis (MFA). The case study demonstrates how the Multilevel SEA method can be employed to assess system transitions and scenarios, in this case, the transition towards a higher share of electric vehicles (EV) until the year 2050 while being employed in combination with different combinations of CE strategies. The consideration of the time dimension further allows assessing CE strategies that affect the lifetime of vehicles or the overall size of the vehicle stock. As a result of the case study, it is shown, among other things, how CE strategies and their different combinations can minimise the efforts in the transition to an increasing share of electric vehicles by 2050, thereby demonstrating how the refined method can contribute to the assessment and decision-making in the transition to a more circular economy.

None

• AB - Utile à l'AB
• FREDO aspect technico-économique
• GEO Autriche
• outil
• tool
• économie circulaire

01/02/2021

1 février 2021