Question on elementar flow

Question

I have noticed that when I include the elementary flow: emissions to air-"carbon dioxide" (no subcategory) it does not show up in the impact assessment, only in the inventory, however if I change it to carbon dioxide, fossil, it shows up. Why is it so? What are the characterisation factors for carbon dioxide (I looked into the eco invent LCIA metods and they mention 3 carbon dioxide emissions;  biogenic, fossil and land transformation, does this mean that I need to be extra careful to chose one of these three wen modelling?)

Answer 1

Turns out this was due to a difference between the ecoinvent impact assessment method and the one from openLCA, which I guess I should have thought of. For example in the ecoinvent version of CML 2001 only "carbon dioxide, fossil" and "carbon dioxide, from soil and biomass" seems the be included. The open LCA version also includes "carbon dioxide", "carbon dioxide, biogenic", "carbon dioxide, land transformation" and "carbon dioxide, in air".

Mystery solved

Comments

Hi Frida,
Then, in the version of CML 2001 just can include the elementary flow "carbon dioxide, fossil" and "carbon dioxide, from soil and biomass" ?
Thanks!

Answer 2

Hi Frida,

I assume you are assessing GWP? The ecoinvent methods are provided by us "as is", i.e. as they are provided by ecoinvent. We will, today or tomorrow, release an own, updated and expanded package for LCIA methods, which we extensively tested. From what you report, not all CO2 flows are characterised in the category you are assesssing.

Best wishes,

Andreas