Measuring the Circular Economy Inside European Union, Using Sankey’s Diagram of Material Flows and Fuzzy Clustering

Recently, the circular economy concept has been almost seamlessly integrated into all key strategies, action plans, and policies across international institutions. An example in this case is represented by the European Commission’s Circular Economy Action Plan, along with Sankey’s Diagram of Material Flows, which will both describe in detail the potential and necessary transition to the new economic framework. Based on that, in the current paper, we have proposed a model that splits the diagram into inputs and outputs, with two correspondent datasets and two research objectives: identify the main producers and owners of materials, and highlight the main types of actors concerning the outflow systems. To reach these objectives, we have computed the Unsupervised Possibilistic Fuzzy C-Means Clustering (UFPC) algorithm. As a result, in the case of the inputs dataset, the computation allocated the 27 member states of the European Union into four clusters, as follows: high-scale, medium-scale, and low-scale resource owners and producers, and importers. When referring to the output data, we have also obtained four allocations, three of those based on the volume of emissions and the performance of the waste recovery system (high, medium, low), and one showing the outlier countries with the highest volumes of waste landfills. Therefore, the constructed model will be relevant for the current European context, while also filling in the gap in terms of using fuzzy clustering as a machine learning algorithm.