Approach for ODS Substitutes from refrigerants

[bl-young]

This relates to emissions from Table 4-124

[bl-young]

CEDA utilizes total "Refrigeration/Air Conditioning" emissions and attributes across all sectors based on Use table data for purchase of Air conditioners (333415).

Flowsa relies on the individual sub categories:

Mappings are specific for each sub category - this results in a fairly significant reallocation between commercial / industrial / residential (presumably the Use table split between these large sectors does not match the emissions reported in GHGI)

[bl-young]

The adjustment to attempt to differentiate by gas is also different, where CEDA adjusts the CO2e values based on changes between AR5 and AR6, and makes some assumptions regarding which pollutants stem from which activity:
https://github.com/cornerstone-data/bedrock/blob/5db90cdaa7666856c9cae4cd67ec258ed6080121/bedrock/extract/allocation/epa.py#L1014-L1050

While in Flowsa, the breakout of HFC type is assumed the same for all activities.

[WesIngwersen]

EPA used the Vintaging Model (VM) for these estimates which is a highly detailed bottom-up model of using of ozone depleting substances (ODS) substitutes (which is generally HFCs) across equipment types with estimates of chemical loads and loses across different equipment phases/time. Details are in the Appendix to the US GHGI. Through this model the data are available by specific GHG by equipment type but the total loads and emissions for specific equipment are not published in the Appendices as (I assume this is the reason) the model does rely on some confidential business information (CBI).
Presentation here: https://climate-transparency-platform.org/sites/default/files/2024-06/D5_ODS_Dave%20Godwin.pdf

It would be difficult to use the data from the model directly even if we had access because NAICS based assignment is not always clear on this equipment, but individual gases would get resolved by equipment.