Main product and side stream allocation

Product LCA & EPD
1

Hello community!
What would be the correct way to allocate?

Process gives out main product and side stream (doesn’t meet the quality requirements of main product). Part of the side stream is treated as waste, part of it is sold as such and part is directed to the next system as secondary material. Basically at this point only main product and the sold fraction of side stream have economic value and difference is so big that economic allocation must be applied. The secondary material fraction is made into product in next system.

Should the burden of the process and upstream be allocated to the main product and the sold fraction OR main product and sold and secondary material fractions? If the secondary material is to be included in allocation, how should I define its economic value? Should it be same as the sold fraction or should I try to estimate it by its share in next system product and thus its share of the product price?

2

Hello Vilma!
Thank you for your question.
If the secondary material has significant value in the next system, it should be included in the allocation, and its economic value should be estimated. However, if its value is negligible, you can allocate the burdens only between the main product and the sold fraction.
To estimate the economic value of the secondary material, you have two options:

  1. If the secondary material is used for similar purposes as the sold fraction, you can assign it the same value as the sold fraction.
  2. Alternatively, you can use the value of the raw material that the secondary material substitutes in the next system .

Whichever decision you make it is important to describe it clearly in the background report and the EPD.