Treatment of embedded carbon in feedstocks

[jayfuhrman]

In looking at the current carbon-management.yaml file for reporting GCAM results for the scenariomip project, there doesn't seem to be a clear way of classifying carbon embedded in feedstocks.

Not sure how other models handle this but GCAM reports non-combustion use of refined liquids products to produce e.g., plastics + asphalt as "carbon sequestration". However the carbon dioxide isn't actually captured for this purpose, it's just already embedded in the petroleum or gas used to produce feedstocks, and then not emitted at the manufacturing facility.

The closest variable definition for this appears to be Carbon Capture|Utilization|Materials|Short-Lived or Carbon Capture|Utilization|Materials|Long-Lived, depending on whether the feedstock in question is used for plastics (short-lived), or asphalt (long-lived)

Alternatively, do we want to create a new variable definition (e.g., something like Carbon Capture|Feedstock Embedded Carbon|Materials|Short-Lived), or simply omit non-biomass feedstocks where there is no dedicated effort to capture a CO2 stream and incorporate it into the product, from the reporting templates?

@christophbertram @jonsampedro @IAMconsortium/common-definitions-emissions

[fschreyer]

Thanks for bringing this up. I think, there are generally a couple of open questions on the treatment of feedstocks and their carbon flows and emissions.

In REMIND, we report non-fossil feedstocks in long-lived products / landfills under Carbon Removal|Long-Lived Materials. One purpose of introducing variables for "Embedded Carbon" could be that one could track how much carbon (of which origin) goes where in the end. Also, it could be used for consistency checks as I would suppose that emitted fossil / stored non-fossil carbon should show up as positive / negative waste emissions in the model somewhere. However, I am not sure about the priority of this level of detail right now. Maybe people with dedicated projects on chemicals and circularity can say more.

I do not entirely understand the difference between Carbon Capture|Utilization|Materials|Short-Lived and your proposal Carbon Capture|Feedstock Embedded Carbon|Materials|Short-Lived? Is it about whether or not the material was produced via CCU? In my understanding, e.g. fossil carbon in plastics made from oil should not be treated under a "carbon capture" variable because I associate carbon capture with capturing CO2 from a flue gas.