The Green Grid is a non-profit IT industry consortium dedicated to promoting energy efficiency in data centres. It defines models and metrics, and develops standards and best practice procedures as well as promoting the adoption of energy-efficiency measures. The organisation’s promotion of the Power Usage Effectiveness (PUE) metric, which compares total data centre power consumption with that consumed by the IT equipment, is now a standard measure of data centre power efficiency.
Now the organisation has announced two new metrics designed to help improve the sustainability of data centre facilities by measuring the effectiveness of carbon and water use. The new metrics are called Carbon Usage Effectiveness (CUE) and the Water Usage Effectiveness (WUE – due in Q1 2011). CUE will help managers determine the amount of greenhouse gas emissions generated in delivering work from the IT equipment, while WUE will assess the amount of water used by the facility and to deliver work from IT operations.
A white paper outlining the new CUE metric and its calculation are available from The Green Grid’s Web site. WUE details will be available when it is released.
An interesting development. The first thing that springs to mind is what carbon is included in the CUE? The Green Grid is clear on the point; ‘Both CUE and PUE simply cover the operations of the data centre. They do not cover the full environmental burden of the life-cycle of the data centre and IT equipment’. The (understandable) reason is that attempting to determine the carbon generated in the manufacturing and shipping of the IT equipment and the data centre would make it too difficult to use.
On this basis, then, if all the energy in the data centre comes directly from the grid, the CUE will be the same as the PUE (since there will be a common conversion factor for power to emissions). Only if there is some local generation are the figures likely to differ. There is some devil in the detail, but the Green Grid is working on that. The WUE is likely to be more complex, which might explain the later launch.