The Green Grid consortium has announced plans to create a "top-to-bottom" design guide for building energy-efficient data centres, as well as new metrics for estimating data centre productivity.

The plans will be discussed at the Green Grid's second annual conference in San Jose, California, where the consortium will also provide some advice about how to use its PUE (Power Usage Effectiveness) metric introduced last year, which provides a way to measure data centre efficiency.

The consortium's members are mostly IT vendors, but also include some end-user companies, such as The Walt Disney Company and eBay. It was set up two years ago to produce tools, metrics and educational resources to help solve the problem of escalating power consumption in data centres.

The 'Data Center 2.0' design guide will offer ways to minimise energy use for both new facilities and those being retrofitted, said Mark Monroe, a Green Grid board member and the director of sustainable computing for Sun Microsystems. The first release will be out in about a year, he said.

"It's meant as an end-to-end guide, from the IT equipment all the way through to the facility infrastructure that supports it, and as a top-to-bottom guide, from measurement and management through to operations and how you run the data centre," Monroe said.

There is already a plethora of documentation devoted to reducing energy use in data centres. The Green Grid says there remains a need for a "single authoritative source" that looks at data centres holistically.

It was the Green Grid that came up last year with the PUE ratio, which provides a way to measure overall data centre efficiency and has been used by Microsoft and Google to show off the efficiency of their most state of the art data centres.

It can be hard for everyday companies to know what sort of PUE ratio they should aim for or how to measure it, so the consortium will also release a paper in the coming months that tells them just that, said John Tuccillo, another Green Grid board member and the vice president for global industry and government alliances with American Power Conversion.

The consortium will also propose methods for measuring the "useful work" performed by data centres. All these metrics are important, proponents say, because businesses can't set accurate targets for energy efficiency if they don't know how efficient their data centres are to start with. "You can't manage what you can't measure," is a refrain commonly heard at these conferences.

The US Environmental Protection Agency has estimated that data centres accounted for 1.5 percent of the nation's electricity consumption in 2006, and it said that figure could double by 2011. Many companies are facing energy problems in their data centres, as powerful modern servers and the shift to doing business online stretches their power and cooling capacities.