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Hello! I`m just starting to use openLCA 1.10.2 and I`m following the case study of the PET Vs PC bottle, I already installed it and I wanted to get more familiarized with the software by following this case example. But when I have reached the section to compare the environmental impacts of the product system PET Bottle and PC Bottle Production(Section 7.2) encountered something strange that I hope to get help with. Impact results obtained were not matching with the actual results .I used the same inputs, LCD database 3.2 and LCIA methods openLCA LCIA methods v1.5.7 as mentioned in the tutorial manual and the only difference was openLCA Software version(In tutorial LCA was carried out with OpenLCA 1.8). Using the same method (CML (baseline) [v4.4 January 2015]) for GWP 100 and Human toxicity and the results are very different. Comparing GWP 100 results obtained for PET Bottle  0.10831 Kg CO2 eq. (from tutorial results) whereas results which i obtained was 2.69128 Kg CO2 eq. 
Do you know why there is such a large difference using the same method for the same system?
Anybody help? :)

in openLCA by (170 points)

2 Answers

+1 vote
by (2.0k points)
Hi Ankit,

I think that the tutorial covers automatically linking processes to create the product system and manually linking to do it. A common thing with our students (and when I did it) is that their manual linking might be to very slightly different processes or something like that. For ELCD this can cause big differences as not all flows have appropriate providing processes.

I suggest maybe look at whether the differences are due to a couple of particular processes.

Hope that helps, Sam
0 votes
by (290 points)


we checked the tutorial and think it should be fine. We get the same results in openLCA 1.10.2 which makes sense as there should not be any difference between the versions of openLCA. 

We recently updated the bottle tutorial to version 1.10.2 (see http://www.openlca.org/learning/). It includes a link to a database (.zolca file) with all elements created during the tutorial. Maybe you can compare your elements with the ones here. In case there are no deviations, feel free to write another message.

Best regards, Pia

by (170 points)
Hello Pia,
thank you very much for the response.
unfortunately it does not solve the problem.
I have still the same result.