View source for Green Power Usage Effectiveness

'''Green Power Usage Effectiveness''' ('''GPUE''') is a proposed measurement of both how much [[sustainable energy]] a computer [[data center]] uses, its [[carbon footprint]] per usable [[kilowatt hour]] (kWh) and  it uses its power; specifically, how much of the power is actually used by the computing equipment (in contrast to cooling and other overhead). It is an addition to the [[power usage effectiveness]] (PUE) definition and was first proposed by [[Greenqloud]].<ref>[https://www.greenqloud.com/greenpowerusageeffectiveness-gpue/ GPUE – Green Power Usage Effectiveness - GreenQloud]</ref>

[[The Green Grid]] has developed the Power Usage Effectiveness metric <ref>[http://www.thegreengrid.org/sitecore/content/Global/Content/white-papers/The-Green-Grid-Data-Center-Power-Efficiency-Metrics-PUE-and-DCiE.aspx The Green Grid - The Green Grid Data Center Power Efficiency Metrics: PUE and DCiE] {{webarchive|url=https://web.archive.org/web/20090217182325/http://thegreengrid.org/sitecore/content/Global/Content/white-papers/The-Green-Grid-Data-Center-Power-Efficiency-Metrics-PUE-and-DCiE.aspx |date=2009-02-17 }}</ref> or PUE to measure a data centers' effectiveness of getting power to IT equipment. What the PUE tells in simple terms is how much extra energy is needed for each usable kWh for the IT equipment due to the power going into cooling, power loss etc. and it's a simple formula (in theory):

PUE = Total Facility Power/IT Equipment Power

The PUE can change depending on where measurements are made, when they are made and the timespan the measurements are made in.
Data centers are subtracting factors from their PUE to lower it e.g. district heating. Some of the issues with PUE are being addressed with the PUEx definition.<ref>[http://www.serverproblemsolved.com/itprimers/pue-power-usage-effectiveness-metrics-data-center-energy-efficiency-green-grid/ New PUE (Power Usage Effectiveness) standards for data center energy efficiency]</ref>

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 CO<sub>2</sub> 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)<br>
or = G @ PUEx  (a better display and for CO<sub>2</sub> 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 CO<sub>2</sub>/KWh

G =Σ( %EnergySource × ( 1 + weight) )

P
Example:

PUE 1.20, 50/50 Coal/Hydro<br>
G = 0.5*(1+1.050) + 0.5*(1+0.013)<br>
G = 1.531, GPUEx = 1.84 or 1.531@1.20

Kg CO<sub>2</sub> per usable kWh = (G-1) × PUEx = 0.64&nbsp;kg

==See also==
* [[Power usage effectiveness]] (PUE)
* [[Life-cycle greenhouse gas emissions of energy sources]]
* [[Data center infrastructure efficiency]]
* [[Performance per watt]]
* [[Green computing]]
* [[IT energy management]]

==References==
{{reflist}}

[[Category:Sustainable technologies]]
[[Category:Computers and the environment]]
[[Category:Benchmarks (computing)]]
[[Category:Energy conservation]]
[[Category:Electric power]]