Skip to main content
An emission factor is the conversion rate between an activity and its emissions: kilograms of CO₂e per kilowatt-hour, per litre of fuel, per passenger-kilometre, or per dollar spent in an industry. Factors are the second half of every calculation Salvidia performs. The credibility of your footprint rests on where they come from.

​
Sourcing principles

Salvidia applies factors from published, referenced sources, not proprietary numbers nobody can check:
  • Government-published factors for energy, fuels, and transport in the relevant country. For Australian assessments this includes the factors published by the Australian Government for national greenhouse accounting, covering grid electricity by state, fuels, and waste.
  • Recognised international factor sets where an activity is not covered locally, or where the activity happened outside Australia.
  • Industry-level spend factors for converting expenditure into estimated emissions, matched to the category of goods or services purchased.
Every factor applied in your assessment is attributable to its source. That is what lets a reviewer check any line of the calculation.

​
Why the same activity can have different factors

Three legitimate reasons, worth knowing because they explain nearly every “why doesn’t this match tool X?” question:
  1. Geography. A kWh of grid electricity in Victoria carries a different factor than one in Tasmania, because the generation mix differs. Factors are matched to where the activity happened.
  2. Vintage. Factor sets update as grids decarbonise and methods improve. Two assessments run against different factor years can differ with identical data, which is also why your electricity emissions can fall in a year when your usage did not.
  3. Method. A flight calculated per kilometre and a flight estimated from ticket spend produce different results. Neither is wrong. The physical method is more precise.
When comparing results with another tool, check the factor source, the factor year, and whether the same categories used spend or activity data. In almost every case the difference lives in one of those three.

​
Spend-based factors and their limits

Spend factors represent the average emissions intensity of an industry per dollar. They make full supply-chain coverage possible without surveying every supplier, and they are a recognised part of GHG Protocol Scope 3 practice. Their limitation is that they cannot see supplier-level differences. A dollar spent with a renewable-powered printer and a dollar spent with a coal-powered one carry the same estimate. That is why the methodology treats spend factors as a starting point, upgraded to physical data or supplier-specific figures in your material categories over time.

​
How factors are applied

When data enters Salvidia, each entry is matched to a factor based on its category, unit, location, and period. You do not select factors by hand. The matching is systematic, which is what keeps assessments consistent and comparable year over year.

​
Where to go next