One by one, data centers are going green. On Thursday, eBay became the latest company to commit to powering an expansion of its main data center with little or no carbon-resulting footprint -- in its case, through fuel cells.

The San Jose, Calif.-based company said that it would build the next phase of its central data center so that its primary power source is renewable energy. Its commitment, using fuel cell generators from Bloom Energy, will result in the largest non-utility fuel cell installation in the U.S.

'Raising the Standard'

eBay noted that renewable energy is usually employed to provide supplementary power to an electrical grid, but eBay's data center will design and build renewable sources into the core power infrastructure of the facility, which powers its global e-commerce. The electrical grid will be available as a backup.

Bloom Energy co-founder and CEO KR Sridhar said in a statement that, by "being a trail blazer and deploying a brand new, revolutionary architecture to build its new data center, eBay is raising the standard for the entire industry." In addition to eBay's operations, the data center also supports the company's PayPal and StubHub activities.

Thirty Bloom Energy servers will drive the six-megawatt installation, to power the expanded data center in Utah. Each Bloom server generates 1.75 million kilowatts of electricity per year, and will be located close to the data center to eliminate the losses common to utility grids.

The fuel cells will be powered by biogas, obtained from renewal organic waste. Although the largest, this is not eBay's first foray into renewable energy. At its San Jose headquarters, the company operates a 650 kW solar array and a 500kW Bloom fuel cell installation, plus a 100 kW solar array at the Denver data center. A 665 kW solar array, covering 72,000 square feet, was also installed on the roof of the Utah center earlier this year.

Syracuse, Google, Apple

Energy efficiency and renewable energy is an accelerating trend among data centers, propelled by the cost savings, if not by the desire to remove a few more carbon footprints from the planet. A Green Data Center Conference was held in London in September, and another will be taking place in October in the San Francisco Bay Area.

Green data centers, with varying definitions of "green," have been showcased by such large organizations as Syracuse University. Google, among other large technology companies, has touted its data centers as some of the most energy efficient in the world, noting that they use only about half the energy used by most other centers.

Google obtains a substantial amount of its electricity from renewable sources, including renewable energy-generated power from the grid. Since 2007, Google has committed to being a carbon-neutral company, so that it saves or removes the same amount of carbon emissions as it creates.

Another example: Last month, Apple announced that its new, half-million-square-foot data center in Maiden, N.C., will only use electricity that has been generated by renewable energy. The facility, it said, will be "the most environmentally sound data center ever built." The company's current data center in Newark, Calif., and one being planned for Prineville, Ore., will also become 100 percent renewable.