Will CUE be as popular as PUE? Don't think so

Today the Green Grid announced the CUE metric, Carbon Usage Effectiveness metric to help measure the carbon impact of IT equipment.

CUE is defined as


The carbon emissions divided by your IT load. Provides a ratio of kg/CO2/kWHr where the best is 0.  Note you can be near zero with hydroelectric or nuclear power sourcing.

I think a simpler way to understand the metric is.



You can pick your CEF by site selection.

You can pick your PUE by data center design.

Multiple them and you get the CUE.

But I think this is a metric that will not be popular.  Why? Because what is really important to many people is the total number of metric tons of CO2.  That's an easy number for people to understand.

PUE is an easy metric for people to grasp as the closer to 1.0 the better.  PUE is discussed much more than DCiE.

The news is being spread by the Green IT press.

James Niccolai at PC World.

Green Grid Creates Metrics for Carbon and Water

By James Niccolai, IDG News

The Green Grid consortium, which developed the widely-used PUE metric for measuring energy efficiency in data centers, is developing two more metrics to address carbon emissions and water usage, it said Thursday.

Rich Miller at Data Center Knowledge.

Green Grid Creates Metrics for Carbon, Water

December 2nd, 2010 : Rich Miller

Expanding its focus on sustainability, The Green Grid today announced the creation of two new metrics to measure carbon and water use in data centers. The new metrics, Carbon Usage Effectiveness (CUE) and the upcoming Water Usage Effectiveness (WUE), are designed to build upon the momentum of The Green Grid’s widely-used Power Usage Effectiveness (PUE) metric.

Penny Jones at Data Center Dynamics.

The Green Grid gives birth to two new metrics

Carbon and water are the next targets of the standards body


Penny Jones

The Green Grid is going beyond PUE, unleashing two new metrics on the data center industry it said it hopes will gain the same amount of global traction – CUE and WUE.

Power usage effectiveness (PUE) is now used around the world to measure the amount and effectiveness of power used within the data center. It is hoped that CUE (carbon usage effectiveness) and WUE (water usage effectiveness) will create some more particular challenges in the data center.

One way to view metrics is to change behavior.

Is CUE a ratio of carbon emissions for power going to drive changes in behavior?


Is the total Carbon impact a number people can understand?

You could have a low CUE with horrible IT utilization and a high total carbon impact.  Or you could have a high CUE, high utilization IT with lots of private cloud type of technologies and a low total carbon foot print.

What behavior do you want to drive?

I think the intent is right, the question is whether it will change behaviors.