I am currently working on a project about life cycle models for vehicles on Brightway. The models I am using are inspired from models on the software Simapro. All the life cycle processes are created fine except for the end of life scenarios. On Simapro the end of life scenarios are described with percentages of recycled mass for each type of product (plastics, aluminium, glass, etc) but I can't find how to translate this into Brightway. Do you have ideas on how to deal with these end of life scenarios on Brightway ? Thank you for your answer.
Example of the definition of an end of life scenario on Simapro
There are many different ways to model End-of-Life, depending on what kind of abstraction you choose to map to the matrix math at the heart of Brightway. There is always some impedence between our intuitive understanding of physical systems, and the computational models we work with. Brightway doesn't have any built-in functionality to calculate fractions of material inputs, but you can do this manually by adding an appropriate EoL activity for each input to your vehicle. This can be in the vehicle activity itself, or as a separate activity. You could also write functions that would add these activities automatically, though my guess is that manual addition makes more sense, as you can check the reasonableness of the linked EoL activities more easily.
One thing to be aware of is that, depending on the background database you are using, the sign of the EoL activity might not be what you expect. Again, what we think of is not necessarily what fits into the model. For example, aluminium going to a recycling center is a physical output of an activity, and all outputs have positive signs (inputs have negative signs in the matrix, but Brightway sets this sign by the type of the exchange). However, ecoinvent models EoL treatment activities as negative inputs (which is identical to positive outputs, the negatives cancel). I would build a simple system to make sure you are getting results you expect before working on more complex systems.
