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LCI calculation method and results

Posted: 04 Nov 2014 11:50
by Perasu
Dear all

I have questions about LCI calculation method and results using OpenLCA 1.4
1.I'm using ecoinvent database v.2.0 to run case study in OpenLCA and I confuse about LCI results that there are some positive values in input and some negative values in output results. I know that OpenLCA use Matrix inversion method to calculate LCI, so it should be all negative values in input and all positive values in output results. Does anyone can explain to me about this situation?

2.I compared LCI results from OpenLCA 1.4 and SimaPro 7.1.8 using same process and same database (ecoinvent 2.0). The results from both software are difference (quite big), so I would like to know that why do they have different results despite both of them use the same LCI calculation method (Matrix Inversion). Thank you very much

Best regards,

Re: LCI calculation method and results

Posted: 04 Nov 2014 13:04
by aciroth
I needed to check the date of your post - both databases and software that you are using are quite old, SimaPro 7.1.8 is from 2008 ( ... Update.pdf), and the ecoinvent 2.0 database also? I admit we did not test openLCA 1.4 with these, but in principle negative values in input or output can occur due to e.g. system expansion / avoided product system modeling and also waste treatment modeling.

For openLCA 1.4, we performed quite extensive tests with both the "official" ecoinvent LCI result data sets and SimaPro 8 results and found very little differences, mostly rounding errors, which are possible since openLCA is calculating with double precision and SimaPro is using a smart single precision calculation.
I would recommend to use a newer ecoinvent database, at least 2.2 which you should have access to with a valid ecoinvent 2 license.

Best wishes,

Re: LCI calculation method and results

Posted: 04 Nov 2014 13:59
by Perasu
Thanks aciroth for your helpful information.