Hi
I've just recently obtained access to the EN15804 add-on database for ecoinvent v3.8, for which reason I have been modelling in the system model 'cut-off, by classification' previously.
In the transfer of my preliminary results from the previous system model into the EN15804, I've stubled upon some magnitude differenes, which appear to be due to the tracking of biogenic carbon - I might overlook some obvious explanation, but anyhow, I'd appriciate some input to the issue.
Taking an example in the process of 'sawing, softwood | sawnwood', I've been looking into the input and output of the processes in both system models, and they appear similar, considering flows and magnitudes of flows. But when looking into the contribution trees of the processes, respectively in the two system models, some of the biogenic carbon in the cut-off, by classification, appear to be attributed differently.
In both system model processes, a negative input elementary flow of 'Carbon dioxide, non-fossil, resource correction' is added after economic allocation in order to re-balance the non-fossil carbon dioxide resource extraction. This input, appears as direct emissions in the cut-off, by classification system model - but seems to be disregarded in the EN15804.
Am I overlooking an obvious attribution explanation, that differs from the two system models, or is there a tracking difference/error somewhere? :)
Best,
Sarah