Gross said it was unlikely such facilities would have been attempted in the past, but "the whole landscape is changing dramatically with the abundance of natural gas," said Gross. EBay was able to negotiate a 15-year agreement that locked in a price for natural gas as a feed stock for the fuel cell, something that would have been impossible not too long ago. In the last three years, renewed exploration and extraction through the process of fracking, or fracturing of underground rock strata, have increased long-range natural gas reserves in the U.S.
Modern data center design is looking for greener operation along with greater efficiency and resiliency. "What eBay has done (at its Topaz site) is leverage all three elements," said Gross. The fuel cell approach contrasts most sharply with data centers that depend on coal-fired, electricity-generating plants. Coal plants still emit large amounts of sulfur dioxide, carbon dioxide and heat, contributors to acid rain and global warming. Fuel cells appear to produce a much lower level of pollutants.
Also, designing around a fixed-price, fuel-like natural gas represents both a pollution reduction and cost saving feature. Using electricity off the grid has been a rising cost for data center operators. Nelson said electricity costs have risen 5.5% a year for the past eight years in California.
Nelson noted eBay wanted to advance the art of data center construction and produce a smaller carbon footprint in its operations, then share how to do so with the world the way Facebook shared its data center server design in the Open Compute Project.
"We've basically put our money where our mouth is. This is where the transactions go through, this is our revenue," he told the Structure audience.
One obstacle to getting other parties to follow eBay's example is that a data center with fuel cells as the primary power source doesn't match the Uptime Institute's current requirements for data center resiliency. Nelson said it will be necessary to start "a dialogue with the Uptime Institute" to get it to consider the attributes of fuel cells. Nelson believes he has "a more resilient data center" with fuel cells than through reliance on traditional supply and backup means. One fuel cell can fail without bring down the data center. The total power supply comes from a repetition of many identical fuel cell units, and the loss of one represents a small drop in the available power, not a systemic failure.
By eliminating onsite diesel generators and uninterruptible power supplies, eBay has drastically changed the backup power side of data center design. "Those are huge components. You no longer need them in this design," said Nelson.