eBay announced this week that its expanded data center in Utah will rely on a 6 MW fuel cell array supplied by Bloom Energy, based in Sunnyvale, Cal., which makes an innovative solid oxide system. It will be the largest stationary fuel cell bank ever installed in a non-utility setting, and the first time a data center has been designed to rely on fuel cells as its primary energy source, with the grid serving as backup. The normal procedure is for data centers to get electricity from the grid, with some kind of backup system to kick in when the grid goes down—an expensive procedure.
The decision by eBay to commit to the Bloom energy system represents a significant vote of confidence not only in the company, which has has set itself the strategic objective of perfecting a fuel cell system reliable enough to power data centers, but also in the broader technology. A decade ago, mobile fuel cells fell out of favor and largely out of public view, when they failed to revolutionize vehicular transportation as manufacturers had promised. But meanwhile, makers of larger, stationary fuels cells have made steady if undramatic advances, building incrementally on existing technology like the solid oxide cell.
Advantages of the solid oxide fuel cell, which uses a ceramic electrolyte, include high efficiency, reliability and durability. A disadvantage is its high operating temperature, though waste heat can be used to generate the steam needed to reform a hydrocarbon feedstock. In the basic process, fuel reformed at the cathode—basically a source of hydrogen molecules—combine with oxygen from the anode to generate a current, with water and carbon dioxide the waste products. Bloom says it has made improvements in both materials and design, and though the details are proprietary, its claims appear to be validated by its market success. In the particular case of the fuel cell array Bloom is supplying eBay, most or all of the fuel is supposed to be derived from biogas. (Bloom's press release says flatly that the fuel cell bank will be powered by biogras; but an eBay spokesperson told the New York Times that eBay "would pay a premium to enable the production of biogas somewhere in the United States in amounts comparable to its gas usage in South Jordan [Utah]."
In principle, whether the plant is running exclusively on biogas or biogras production is being subsidized to compensate for natural gas consumed at the plant, the facility would appear to be doubly green: It runs on a renenewable fuel and produces no solid waste, carbon dioxide being its only undesirable byproduct. So it's easy to see why the Bloom Energy Server is attractive to high-tech companies that depend on big energy-guzzling data centers and fervently wish to build green credentials. Apple has installed a 4.8 MW Bloom system at a North Carolina data center, albeit not one that will emphasize use of biogas. Facebook is putting a data center close to the Arctic Circle in Sweden, so that it can rely mainly on natural cooling rather than artificial refrigeration.