Mar 26 2009

How to Make IT Data Centers More Sustainable

Posted by: Jonathan Marshall

Northern California is a world leader in at least two markets: growing marijuana and high tech. But just as PG&E doesn't know how many marijuana farms grow under lamps inside innocent-looking homes, neither does it know for sure how many IT data centers draw power in its market. PG&E reads the meters but doesn't peek inside customers' premises.

Nonetheless, it's possible to make some informed estimates. The big commercial colocation centers and Internet "hotels," like 365 Main in San Francisco, are no secret; together they draw about 200 megawatts of power within PG&E's service area. The utility's best guess is that private data centers in high-rise office buildings and campuses probably consume an equal amount of power. Then there are the smaller server closets in law firms, boutique financial companies and the like, which might add another 100 megawatts to PG&E's load.

The average large data center consumes as much power as 25,000 households, according to McKinsey. Mark Bramfitt, principal program manager for high tech in PG&E's customer energy efficiency group, says the combined data center market now represents about 2.5 percent of PG&E's total demand, and is growing 15% to 20% per year.

"Last year we hooked up 75 MW of new data centers," Bramfitt told a gathering of the Business Council on Climate Change at PG&E's Pacific Energy Center in San Francisco today. "That's a big challenge for any utility to serve."

To make it easier--and to spare the environment--PG&E has become a leader among the nation's utilities in educating the market and providing incentives to promote more efficient use of energy in data centers.

The waste of energy in most data centers is staggering--on the order of 25% to 50% of total consumption. For one thing, power-hungry servers typically operate at less than 10 percent of their capacity. For another, they receive air conditioning around the clock, even when outside temperatures drop to freezing. Such practices aren't surprising when the IT experts who run the data centers don't pay the power bills.

Computer servers tend to be vastly underutilized because they are assigned specific tasks, like handling email, that may run only occasionally. With so-called virtualization software, servers can share multiple applications. Servers can then be consolidated, freeing up space in overcrowded centers and dramatically lowering overall power consumption.

Energy efficiency champion Autodesk managed to squeeze 296 servers down to only 7. "The energy savings are phenomenal, and now they have room to grow," Bramfitt said.

PG&E offers rebates for businesses that virtualize their servers. The utility currently has more than 200 applications for this incentive program, according to Bramfitt.

PG&E also offers incentives for companies to install software that turns off spinning storage disks when they aren't needed to access data--a measure that can save 75 percent of normal energy consumption. "A certain social networking site, which will remain faceless, bought this application," Bramfitt said. "If you are popular, your page gets moved to the spinning disk where people can access it quickly. But if you are not so popular, they move you onto another disk and turn it off. People can still access your page, it just takes slightly longer."

The next big wave of energy savings may come from turning off around-the-clock cooling systems. "Free cooling is this simple: When it's 50 degrees outside, open a window and turn on the fan," Bramfitt quipped. (Don't forget the dust filter, of course.) NetApp recently scored a $1.4 million incentive check from PG&E for moving to free cooling at its Sunnyvale datacenter. Even without the utility's incentive, a payback time of 6 months is typical when the technology is deployed in a new data center, Bramfitt said.

Last year, PG&E paid out about $7 million in energy efficiency incentives to data centers, reducing overall loads by about 7 MW. "Out of an overall load of 500 MW, that doesn't make me happy at all," Bramfitt said. "We need to drive at least 25 MW a year out of our load." To that end, he's got $50 million to spend over the next three years.

Much as Bramfitt likes his clients, he reminds them that they'll never really be "green." "IT is a big honking energy user," he concluded. "But it can be more sustainable by squeezing the most efficiency out of that energy."

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"PG&E" refers to Pacific Gas and Electric Company, a subsidiary of PG&E Corporation.