The PET bottle case study - Waste incineration does not have environmental impact? (IPCC GWP 100a LCIA)

Question

Dear all,

I have a question would like to ask for your kind help, maybe I get it entirely wrong, so any guidance is highly appreciated!

I am trying on the PET Bottle case study provided by openLCA. While I tried to calculate the LCIA for the product system 'PET Bottle Usage (Opposite Direction Approach)' using IPCC GWP 100a LCIA method, I noticed that there is zero contribution from the process 'Waste incineration of plastics (Opposite Direction Approach)'.

I wonder why this can happen (or does that make sense in the openLCA software) because I expect that this waste treatment process will have some contribution in terms of CO2 eq. 

I saw from the inventory list of the process 'Waste incineration of plastics (Opposite Direction Approach)' that there is CO2 emission to air in the output table.

Please correct me if I misunderstood the logic/concept or how openLCA interprets the result.

Thank you very much!!

Comments

Follow up:
I found the mistake I made: I should choose the 'economic allocation method' while calculating the LCIA.
Because the physical allocation factors in the Process - Waste incineration of plastic (ODA) are all zero. But it has economic allocation factors.

Please correct me if I am wrong.
Thank you!