Problems with calculating allocation factors

Question

Hej

I had calculated allocation factors for my process in the allocation tab. When I wanted to make some changes in the economic values and recalculate them all allocation factors turned to 0 (for all allocation methods) and I cannot calculate new ones. Does anyone have a solution for this problem? (I have already tried to restart program, update Java etc.)

//Frida

Answer 1

Which openLCA version are you using? The factor calculation is really stable, it does not work if formula in the process are incorrect e.g. I would recommend to check that (validate the database or the process where you are working on).

 - and sorry for the late reply!

Comments

I am using 1.7.0 (Mac OS x86_64).

Indeed I did find a problem with my process. I had an out put of district heating as well as three co-product (from a Kraft pulping plant). The allocation was between the three co-products, but I didn't mark the district heating as an avoided product. Once I did this, the allocation factors where calculated.

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Hej Andreas

Here is a follow up question. Why do I have to mark the output of heat as an avoided product for it to calculate the emissions factors? If I unbox it and try to calculate the emissions factors, they are all zero. I looked at my co-workers computer and it doesn't work this way in his OpenLCA with a similar process? It feels weird mixing system expansion and allocation, but perhaps there is an answer to this?

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I think the explanation for this is hinted at in the user manual: " In order for allocation to work, the main product and the co-products of the multioutput process need to have the same flow property."

The manual is not clear about whether they all have to have the same *reference property* or if they all have to have any property in common. Most likely they all have to have the same property as the *reference property* of the *reference output* of the process. In any case, your other coproducts are probably measured in mass, and heat is not.