Where do the emission factors in EsgaSIS come from?
From published national and regional sources, recorded individually with a publisher, a citation, a vintage year and a tier. Singapore factors come from EMA, NEA and PUB; Malaysian grid factors from the Energy Commission and Sarawak Energy; fuels, refrigerants and flights from global references. Every factor names its source in the report.
The factor registry is the source of truth and lives in code, not in a spreadsheet and not typed into a screen. That is deliberate: the previous prototype kept a factor next to each form that needed one, and they drifted apart until the same activity produced different answers on different pages.
Each factor carries:
The activity it converts, and the country and region it applies to.
A vintage year — grids change annually, so a factor without a year cannot be defended.
The publisher and a citation specific enough to find the document.
A tier, describing what the figure IS rather than how good it is: measured, regional, national, global, or a spend-based proxy. Global means the factor is not country-specific — a refrigerant’s global warming potential is a property of the molecule, so a global value for it is as good as a national one could ever be.
A verified flag, set only when the value has been checked against the primary source.