What are Scope 2 emissions?
Scope 2 emissions are indirect emissions from generating the electricity, steam, heat or cooling an organisation buys and uses.
Why it matters
Scope 2 is defined in the GHG Protocol Corporate Standard and set out in more detail in the Scope 2 Guidance. The emissions happen at the power station, away from the buyer's own sites, and are caused by the buyer's demand. The guidance describes two methods: location-based, using the average intensity of the grid, and market-based, using contracts such as renewable energy certificates.
Data centre electricity is the cloud provider's Scope 2. For the cloud customer, the same emissions sit in Scope 3, usually under Category 1, purchased goods and services. It is still the part a customer can change most directly, through region, timing and instance choices.
An example
Two identical workloads run for the same hours, one in a region supplied mostly by low-carbon generation and one in a region that still burns a lot of fossil fuel. The electricity used is the same. The location-based emissions differ, because each kWh is multiplied by a different grid carbon intensity.
How Greenpixie measures it
Greenpixie calculates usage emissions with the location-based method, in line with the GHG Protocol Scope 2 Guidance:
- IT electricity is estimated for each billing line from the hardware behind it
- data centre overhead is added using the region's PUE
- the total is multiplied by the grid carbon intensity for that region and hour
Hourly factors are used where grid data allows, with daily, monthly or annual figures as fallbacks. Grid intensity is split into combustion, which a location-based reporter counts as Scope 2, and upstream and transmission parts, which count as Scope 3.