Glossary
How it is used
Every carbon footprint is calculated with the same operation, repeated for each source:
activity data × emission factor = emissions
Activity data is a quantity you can measure: litres of diesel, kilowatt hours, kilos of gas, kilometres travelled. The factor turns that quantity into emissions, usually in kilos of CO2 equivalent per unit.
An example
10,000 kWh × 0.3 kg CO2e/kWh = 3 tCO2e
The numbers are made up to show the mechanics. The real grid factor changes every year and you have to use the official one for the period.
Where they come from
Official or technical bodies publish them. In Chile, the HuellaChile Program publishes factors in its support material.
What to check
A factor has a year, a country and a source. A serious inventory records all three for each one, because it is the first thing a verifier looks at.
