Part 1a: Material Flow Accounting
Goal: Carry out the material flow accounting for the defined materials and the defined system through data collection and processing. You will arrive at weight-based data for the extracted, imported, exported and wasted materials for two points in time. These feed into a prepared template that automatically produces the circularity indicators and the Sankey diagram.
There are three parts to the MFA. The first one is quite distinct and you will use it to set the scene by defining the system boundaries. Data collection and processing, for which you will use data sheet templates, see in “Tools” below, are a bit intertwined, as it is normal to realise that more data needs to be collected during the processing. Therefore, the latter two are not distinct phases, but instructions and tips are given apart in the respective handbook chapters:
The data collection and processing for the MFA can be accomplished in eight steps, as is illustrated in the below scheme. In the first step, it needs to be selected for each of the materials in the “List of all materials” (see in What are the UCA materials?), if these are extracted, imported and/or exported in the city. Depending on the data availability from (1) the Sector-wide Circularity Assessment of the construction and/or biomass sector that some CityLoops cities have carried out, (2) local data or (3) national data, the next respective steps have to be carried out, although not in a consecutive order (per materials) as could be understood from the scheme.
For example, if local data exists for cereals, it can be used right away and does not have to be searched and possibly downscaled from a higher spatial scale. However, in the overall approach for all materials, the steps should be taken in the indicated order, not least to also include the waste data in the end.
When applying the UCA, a number of files need to be worked with. Some will be raw data files, while others are templates that facilitate the work. These have their own functions, a number of tabs and embedded calculations, and you will carry out respective actions with them. The visualisation helps to understand the names of the files, the working order, your actions with them and how many there are. The templates themselves, are listed below.