Green When It is Hot: Data Centers and Solar Energy
Vertatique posts have covered the attraction of locations that offer renewable energy, typically a combination of hydroelectric power and free air cooling from a temperate/cold climate. But about data centers in sunny climates? The question provided a good opportunity to check in on solar photovoltaic electricity (solar PV) back in 2009. There has been mixed progress since then, with the latest solar-for-datacenter initiatives coming from eBay, Apple and QTS.
One of Vertaique's first posts in 2007 identified California provider Affordable Internet Services Online (AISO) as the only 100% solar data center. We updated that post many times in subsequent years, but never with a new all solar power data center. A January 2009 survey article on Data Center Knowledge turned up very little solar activity.
IO Data Centers in Arizona had been looking at the bright side of its location for a while. In its presentation of energy-saving features, the company wrote in 2009, "Given that our facilities enjoy 300+ days of sunshine each year, we leverage a passive, free source of light to reduce our need for artificial illumination." IO also said that its new Phoenix One facility will strive to generate 4.5 megawatts from a solar array scheduled to be phased in over the course of 2010, combining thermal storage with its solar power to minimize peak electricity purchases. Even then, its massive 5,000 panel solar array would only provide 5% of the needed electricity at a cost of ~2.5x the current market price.
Returning now to the IO web site in 2012, we find no mention of solar for Phoenix or other IO facility. The bottom line seems to be that the disadvantages of a sunny climate - greater cooling needs combined with less free air cooling potential - outweigh the benefits of solar generation.
The latest solar-for-data-centers skeptic is Amazon's James Hamilton, who wrote in his personal blog in March 2012, "I love solar power, but in reflecting carefully on a couple of high profile datacenter deployments of solar power, I’m really developing serious reservations that this is the path to reducing data center environmental impact. I just can’t make the math work and find myself wondering if these large solar farms are really somewhere between a bad idea and pure marketing…" Hamilton goes on to support his skepticism with an analysis of the locations' solar potential for Facebook Prineville and Apple Maiden.
Such questions have not deterred Apple, which has now announced it is building a large solar array for its Maiden data center.
The 665 kilowatt (kW) solar power system, designed and installed by SPG Solar, features 72,000 square feet of solar panels, covering virtually every inch of roof space on the data center to capture the abundant sunshine Utah enjoys nearly year-round. The installation will produce 924,013 kilowatt hours (kWh) of clean electricity annually, which is equivalent to offsetting 702 tons of greenhouse gas emissions or planting 136 acres of pine forests. In addition to the environmental benefits, we see it as a pretty good business investment, too—through a combination of lower electricity bills, Federal stimulus dollars and tax incentives, we anticipate the installation will pay for itself in just four years. The Topaz solar array, along with our 650 kW array and 500 kW Bloom Fuel cell installation at our San Jose headquarters and our 100 kW solar array in Denver, brings our total renewable energy capacity to almost 2 Megawatts. To put that in perspective, that’s equivalent to about 11% of our total US data center electricity demand.
While the Topaz solar installation represents our biggest renewable energy project so far, we also acknowledge the limitations that it represents as we consider eBay’s overall energy mix. Despite the fact that we used all the roof space available, the power generated by the array still represents less than 10% of the total load of the data center.
QTS committed in May 2012 to solar projects that will deliver a combined total of 1 MW to two of its data centers.