Sun Microsystems is showing the public Tuesday how server consolidation and other efforts reduce energy costs, while Fujitsu Computer Products of America has plugged in a new hydrogen fuel cell generator to supply some of the power to its offices in Sunnyvale, Calif.

Server sprawl, rising energy costs and global climate change concerns have made the finance people at many businesses finger their IT departments as the biggest energy waster in the company. Data centers across the United States consumed about 61 billion kilowatt-hours (kWh) in 2006, roughly 1.5 percent of the total U.S. electricity consumption, according to the U.S. Environmental Protection Agency. But those same finance people need to see a favorable return on investment (ROI) before approving a data center upgrade.

Already, Hewlett-Packard has consolidated 85 of its data centers worldwide into six, while IBM will replace 3,900 servers in its data centers worldwide with 30 mainframe computers.

Sun has scheduled a webcast event Tuesday at its Santa Clara, Calif., headquarters touting its Eco Innovation Initiative of building energy-efficient data centers in Santa Clara, Blackwater in the United Kingdom, and Bangalore, India.

In Santa Clara, for instance, Sun reduced its server count to 1,240 from 2,177 and its storage hardware count to 225 from 738, all while achieving a fourfold increase in computing power. The upgrade reduced Sun's electrical use to 500 kilowatts, from 2.2 million megawatts, and earned Sun a US$1 million rebate from the local electrical utility, Silicon Valley Power.

But even Sun had to convince its finance people to approve the project, said Dave Douglas, vice president of eco responsibility at Sun.

"It's really a fairly new idea that the energy efficiency will pay for these systems," Douglas said, adding that Sun's project will pay for itself in three years. He suggests companies do a small project in a part of the data center first, and if they can quantify the ROI from that, "it would get the finance people all excited about it."

Rebates also figured into Fujitsu's installing a hydrogen fuel cell generator at its offices in Sunnyvale, which was christened Aug. 17.

The 200-kilowatt generator is fueled by natural gas, which, while it generates carbon dioxide, captures waste heat and uses it to heat the building's water and air.