Analysis Groups - Additional guidance and waste treatment processes

Question

Dear community,

I have recently experimented with the Analysis Groups of openLCA.

I am seeking for clarification/support in a few areas. I appreciate any valuable infos on the following:

1) As also shown in this post , under some circumstances, all analysis groups show zero in complex systems. I have allocated maximum memory to openLCA. I played around a bit with assignin different groups but I did not really understand, when this "error" happens and when not. Overall I would like to use the analysis groups more, but as i am seeking for consistency in my workflow, information on how to systematically avoid this error would be great. I think it has something to do with the upstream calculations, because in the aggregated EF 3.1 database it worked perfectly, however in ecoinvent unit processes, the method seems to struggle a bit.

2) Are analysis groups implemented for waste treatment processes? I am referring to the thought that for waste treatment processes, the process chain is built in the other direction as for traditional processes. Shouldn't then the analysis group of a waste treatment process include all of its downstream instead of its upstream?

Thank you in advance,

Paul

Answer 1

Hi Paul,

indeed, if you make the system very "looped", the calculation can become complicated, if you have the system structure more like a tree, for your foreground system, it works quite fine. Easiest is of course with system processes (thus the EF database is easier here) but it works also with unit processes in my experiences, and also with waste flows. To provide more specific feedback, you would need to post your model graph here, or you can book a support hour from Nexus, then someone from us could have a look. Thank you!

Andreas