There has been a growing interest in buying low-power servers, and Energy Star could guide companies in the right direction, Brookwood said. Cloud companies like Facebook and Google buy servers in volume to boost performance while lowering power costs. There also is a growing interest in low-power ARM processors, which are used widely in smartphones and tablets, as an alternative to the more power-hungry x86 processors from Intel and Advanced Micro Devices, which are used in most data centers.
There is a need for standardized ways to measure power, but servers are different as the metrics are too vast to put under a single measure, said Dan Olds, principal analyst at Gabriel Consulting Group.
Energy Star works well with air conditioners and dishwashers because those appliances do simple things, and it is easy to measure power consumption and assign a score to it. Server behavior is complex and workloads are based on different attributes, making it difficult to apply a specific metric to determine power consumption.
"An application that is CPU dependent will use power at a different rate than an application that is doing Web surfing and sending out traffic over a network," Olds said.
EPA is working with top server makers and nonprofits to come up with Energy Star 2.0, and are fully capable of coming up with a standard, Olds said. But there are too many considerations to take into account with servers and the standard could end up being deceptive, Olds said.
The idle power limit in Energy Star 2.0 for servers has been set at between 47 watts and 57 watts for one-socket servers and between 92 watts and 142 watts for two-socket servers, less than limits set in the Energy Star 1.0 specification. An additional power allowance is given when components are added: for example, an extra hard drive gets eight watts of power, while additional RAM exceeding 4GB gets 0.75 watts of power per gigabyte. Power supplies are assigned 20 watts of power per unit.
The new specification does not consider high-performance computer systems, fault-tolerant servers or server appliances, which are typically used for specific tasks such as storage or networking.