How to assign allocation to material and energy products in LCA in mutifunctional systems (e.g., biorefineries)?

Question

Hi everyone,

I'm new here, but hoping I can get some help from somebody.

Currently working on an attributional study of a multifunctional biorefinery system which produces a number of products including material and energy products. In attempting to calculate allocation I've been getting a notification that "there is no common flow property of the product outputs and waste inputs that could be used to calculate allocation factors" (see image below). This occurred during mass allocation, which was probably due to the challenge of mixing material and energy outputs. To get around this, I assigned each product  (material and energy) an economic value, and then attempted to re-run allocation using economic allocation, but I still got the same message. Does anyone know what I'm doing wrong? I assumed using economic allocation would get around the problem.

Thanks in advance

James

Answer 1

Hi James,

welcome - you did not post a picture, you can assign a new flow property for the flows, to allow openLCA a conversion, if this makes sense for your flows (so e.g., add a heating value for wood that is used, in additon to mass, so that all flows have energy-based flow properties and thus can be converted; of course it would not make sense to add a mass-based flow property for electricity e.g. so this does not always work). Allocation is quite extensively explained in the openLCA manual, e.g. here: https://manuals.openlca.org/openlca/allocation.html, also economic allocation.

Hope this helps, Andreas

Comments

Thanks very much Andreas. Very helpful. Kind regards,

James