Bizarro, Diana; Hauck, Mara; van Harmelen, Toon

The Dutch climate policy establishes that the Netherlands should reach 50% circularity and 49% less CO2 emissions compared to the 1990 levels by 2030. By 2050 the goal is to be 100% circular and emit 95% less CO2. New business models and technologies are under development to allow the Netherlands to reach their goals. However, up to now there is no standard methodology to assess the circularity of a product and even less a way to do so integrating its environmental impacts in the analysis. Saidani et al (2019) identified 55 circularity indicators that can be used to evaluate circularity at different scales. However, none of them sufficiently consider the thermodynamic limits for recycling processes. Exergy, entropy, statistical entropy and other thermodynamic based indicators have been pointed out as a possible solution. Are thermodynamic based indicators the silver bullet for assessing circularity and environmental impacts? To answer that, five circularity and thermodynamic indicators were selected using the following criteria: suitability for product scale assessment, data availability, complexity of application. Next, their relevance to circularity and sustainability assessment was evaluated in a case study of a Li-ion traction battery recycled through pyrolysis. An LCA analysis was included to determine whether circularity and environmental impact results were aligned. The results show that circularity and thermodynamic indicators have different applications within the circularity framework since they take different aspects of a product system into account, thus the best circularity indicator for an assessment will depend on the goal of the study and the product assessed. Furthermore the recycling path scoring the highest in circularity is not always the one of lowest environmental impacts. Therefore, circularity indicators and environmental impacts should be used and analysed together.