Modelling EoL as Opposite Direction Approach in ecoinvent

Question

Dear all,

I am modelling a textile life cycle from cradle to grave in openLCA with the database ecoinvent 3.4. As my database of ecoinvent is older than version 3.6, I need to apply the Opposite Direction Approach (ODA) for the EoL modelling. I checked the manual of GreenDelta and the entries in aks.openLCA but nevertheless, I faced some issues with finding out how exactly ODA is applied. As I understood it correctly, I need to insert the waste treatment flows under input with a negative value (marked with red).

My questions are:

1. did I enter the flows at the right places?

2. are the flows waste for incineration and waste for landfill the correct ones as they appear a bit odd to me as I am not able to pick a "normal" provider for them. Furthermore, I can not see the inputs and outputs (like emissions from incineration and energetic credit due to incineration) of those flows like in the example of the manual.

Thank you very much for answering my questions!

Cheers, Anna

P.S. I need to upload the picture seperately as the platform does not support the screenshot in my text.

Answer 1

Hi Anna,

sorry I thought this question was already answered but it was just your added screenshot - the opposite direction approach always requires changes on two sides, for one on the process that has waste output (move waste to input, change sign to negative) and second for the waste treatment process, move waste that is input to output and change the sign there as well. I call it therefore a "double negative" approach. If you forget to change the sign on one of these sides, you get negative results obviously for this life cycle branch. The waste treatment processes are modeled by yourself, right (I did not check now but sPET use does not sound like an ecoinvent process) - then this could be the issue.

You can of course add pictures in posts, you can also edit your post to avoid adding an additional answer or new post btw..

Success!

Andreas

Comments

Hey Andreas,
 
thanks for your answer.
I've got my problem fixed with adding an extra flow under output in the waste treatment process with a negative sign. Then I added this flow with again a negative sign in the input in my waste generation process. This worked for waste incineration and waste landfill.

Cheers, Anna

Answer 2

Here comes the screenshot of EoL modeling in openLCA: