Some go solar, but Fujitsu is giving the fuel cell a try for its data center in Sunnyvale -- a first for Silicon Valley. A unit from UTC Power, which produces power from natural gas, will generate 50 percent of the power used to cool its servers.

DailyTech offers some details.

The fuel cell used by Fujitsu is a UTC Power PureCell Model 200 (200 kilowatts of assured power) which is California Air Resources Board (CARB 07) compliant. The unit produces 35 percent less CO2 power mW-hour, saves 800,000 gallons of water per year and 4,000 pounds less NOx per year than traditional power plants.

Better yet, according to Fujitsu's estimates, the PureCell 200 will have paid for itself in 3.5 years.