Data discrepancies in Excel exportation

Question

Hello Team openLCA,

I'm having a few problems exporting my LCA results from openLCA to Excel. Although the export itself works perfectly, the data present in Excel differs from that in openLCA's "Contribition tree" tab. For example, the climate change calculation for the "milk production, from cow - CA-QC" flow gives me a result of 1.243 kg CO2 eq./kg on OpenLCA, whereas the Excel result is 2.359 kg CO2 eq./kg. This problem occurs in around 15% of the flows making up my process and this applies to data from both Ecoinvent and Agribalyse. Could you tell me which data I should rely on? OpenLCA data or Excel data?

Best regards,

Jade

Answer 1

So you export the normal impact analysis results to excel (or the entire calculation results) not the contribution tree, right? Meaning that "excel data" in your question is also openLCA result (and maybe not "data"), just as contribution tree results.
The point is that the contribution tree shows individual branches / pathways of supply with their impacts, while the impact analysis results show the aggregated result, over all branches. In LCA systems, supply chains are used often more than once, also due to loops, and thus the result per supply chain is different, and often lower, than the overall result. I hope it is clear now?