I am currently using Open LCA to do an assessment of a system that produces multiple products, specifically a biorefinery. I am going to use the system expansion method in order to avoid allocation.
According to the OpenLCA user manual, to apply the system expansion there is a tool named "avoided product", in which one have to select the products that are not going to be the main product.
My doub is if the way that the software calculates the final result is this: The summation of the environmental impacts of the avoided products are subtracted from total impact of the system to obtain the impact assigned to the main product??
I have this doud because i have seen that in the literature there are authors that mention the use of a substitution factor in the systen expansion method, that is why i have the doubt.
Thank you in advance.