The Green Grid, an organization that focuses on data center efficiency measures, is out with three new measures for assessing the efficiency and carbon footprint of a data center. They are:
1) Carbon usage effectiveness (CUE)
2) Green energy coefficient (GEC)
3) Energy reuse factor (ERF)
CUE measures the absolute carbon usage of the data center per unit of energy used by the data center, or effectively how clean the data center’s power is. The GEC measures the percentage of energy being used in a data center that is sourced from clean power.
David Chernicoff over at ZDnet argues that these are “feel good” metrics, though I’d characterize them more as a reflection of the fact that top tier IT companies like Google, Facebook and Amazon are under pressure to source clean power. And I suspect that sooner or later one clean energy or carbon metric will be taken seriously and published by these IT companies.
ERF is actually the most interesting new metric of the bunch since it measures how much of the energy that a data center uses is reused outside of the data center. While it’s not possible for most data centers, many data centers can do things like take the water that is used to cool a data center and pump the now warm water outside the data center where it heats another portion of a facility, effectively lowering heating costs and energy used. This metric will, at the very least, get people thinking about whether they even can reuse energy that was initially consumed in the data center.