What is CO2e?
CO2e, or carbon dioxide equivalent, expresses the global warming potential of different greenhouse gases as an equivalent amount of CO2.
Why it matters
Each greenhouse gas traps a different amount of heat, so a tonne of one cannot simply be added to a tonne of another. Converting each gas by its global warming potential puts them on one scale. That gives a single total an organisation can report, compare with last year and compare with other suppliers. tCO2e means tonnes of CO2e and gCO2e means grams.
The GHG Protocol Corporate Standard covers seven gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, sulphur hexafluoride and nitrogen trifluoride. Reporting in CO2e is what lets all of them sit in one inventory.
An example
A cloud workload's footprint mixes several sources. Power stations emit when they burn fuel, more is emitted producing and transporting that fuel, and some electricity is lost in the wires. The servers also carried emissions from manufacture. Because each is expressed in CO2e, they can be added into one figure per line of a cloud bill.
How Greenpixie measures it
Greenpixie reports every figure in CO2e, at the unit that suits the decision:
- usage emissions for each cloud billing line, in tonnes CO2e
- manufacturing (embodied) emissions for each line, in tonnes CO2e
- a combined total of the two for each line
- AI carbon per token, in grams CO2e, with an interquartile range
- grid carbon intensity per cloud region and hour, in tonnes CO2e per kWh
Grid intensity is held as three components, being combustion, upstream and downstream, and transmission and distribution losses. That lets a customer split the electricity figure between Scope 2 and Scope 3.