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Hello

This has been answered partially in How to calculate the GWP-GHG indicator when using OpenLCA and 15804 A2 2020 impact assessment methods Ashraka_ and Conrad

Please may you confirm the characterisation factors to set to zero are as below (and no other changes are needed):

Many thanks

FlowCategoryFactorUnitUncertainty
Carbon dioxide, from soil or biomass stockElementary flows/Emission to air/low population density0kg CO2 eq/kgnone
Carbon dioxide, from soil or biomass stockElementary flows/Emission to air/unspecified0kg CO2 eq/kgnone
Carbon dioxide, in airElementary flows/Resource/in air0kg CO2 eq/kgnone
Carbon dioxide, non-fossilElementary flows/Emission to air/high population density0kg CO2 eq/kgnone
Carbon dioxide, non-fossilElementary flows/Emission to air/low population density0kg CO2 eq/kgnone
Carbon dioxide, non-fossilElementary flows/Emission to air/unspecified0kg CO2 eq/kgnone
Carbon dioxide, non-fossil, resource correctionElementary flows/Resource/in air0kg CO2 eq/kgnone
Carbon dioxide, to soil or biomass stockElementary flows/Emission to soil/agricultural0kg CO2 eq/kgnone
Carbon dioxide, to soil or biomass stockElementary flows/Emission to soil/unspecified0kg CO2 eq/kgnone
in openLCA by (120 points)

1 Answer

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by (7.2k points)
Dear Pete,

Yes that's correct. When switching from the GWP-total indicator in EN15804+A2 to the additional GWP-GHG indicator, or sometimes called GWP-IOBC, the rules inside, for example, PCR 2019:14 only switches the biogenic carbon dioxide from -1/+1 to 0/0. Surprisingly the PCR is not changing biogenic methane from 29.8 to 27.0 accordingly, as it would be the case for the normal IPCC (incl. biogenic uptake and emissions) and as it is used in ISO14067. Depending on the PO of your EPD and the PCRs, you can check for example the PCR 2019:14 from EPD International where the factors for GWP-GHG are shown in the appendix.

So the elementary flows that you mention are correct, except for "Carbon dioxide, to soil or biomass stock" and "Carbon dioxide, from soil or biomass stock". These flows stay as they are (untouched). They are not set to zero, because they are tracking the biogenic carbon from land use and land use change. Because this biogenic carbon comes to the stock much earlier than the scope of any LCA, it is treated/characterized the same way as fossil carbon (see the LCIA methods manual from ecoinvent for comparison). So just let them as they are and do not set them to zero.

To follow the PCR and the GWP-GHG indicator, you only need to set all "Carbon dioxide, non-fossil" and all "Carbon dioxide, in air" and all "Carbon dioxide, non-fossil, resource correction" to zero. You can also simply remove them from the characterization factor table in openLCA, which will have the same effect as setting them to zero. If you do one of this, you are fine. Before doing this you can simply copy/paste the impact category GWP-total from EN15804+A2.

By the way, in our newer add-ons for EN15804 and with ecoinvent 3.10 or newer, we have the additional GWP-GHG indicator already included in the methods.

Best wishes,

Conrad
by (120 points)
Conrad many thanks for your speedy answer.
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