Photos: How data centers are cooling down

High-tech data centers make up less than 2 percent of U.S. energy consumption, according to the Environmental Protection Agency. But their growing hunger is posing a challenge to utilities.

California data centers from the Oregon border down to Bakersfield now demand as much as 500 megawatts, which could grow by another 50 to 70 megawatts within the next 18 months, according to Mark Bramfitt, program manager for customer energy efficiency at Pacific Gas & Electric.

Aiming to pool efforts to green the grid, the electricity provider last week brought together efficiency experts from 19 utilities in California, Texas, Vermont, New York, North Carolina, and elsewhere.

The group on Friday toured several Silicon Valley tech companies making progress to cut energy waste, such as NetApp's data center shown here. Utilities view such efficiency efforts as low-hanging fruit that may be less showy than "green" options like solar power, but can deliver faster cost savings and greenhouse gas reductions.