It is an addition to the power usage effectiveness (PUE) definition and was first proposed by Greenqloud.
Data centers are subtracting factors from their PUE to lower it e.g. district heating.
[3] GPUE is a way to "weigh" the PUE to better see which data centers are truly green in the sense that they indirectly cause the least amount of CO2 to be emitted by their use of sustainable or unsustainable energy sources.
This new metric GPUE or Green Power Usage Effectiveness is defined as:
GPUE = G × PUEx (for inline comparison of data centers) or = G @ PUEx (a better display and for CO2 emission calculations) The "G" is the key factor here and it is a simple calculated value: G = Weighed sum of energy sources and their lifecycle KG CO2/KWh G =Σ( %EnergySource × ( 1 + weight) )