This 83,000 square foot solar array will produce more than 1 megawatt of power for a new data center in the Sonoma Mountain Village development in Califonria.
The Internet-scale solar data center will have to be a big sucker. That’s because it takes about 7 acres of solar panels to generate 1 megawatt of power, according to Peter Panfil of Emerson Network Power, which built a smaller solar array on the roof of a new data center on its headquarters campus in St. Louis.
“A large photovoltaic array is needed to make it work,” said Panfil, vice president and general manager for the Liebert AC Power business of Emerson Network Power. “The challenge was how much we could really generate on our own. We decided to do as much as we could.”
Emerson built a 7,800 square foot solar array with more than 550 panels, which is the largest solar array in the state of Missouri. But its peak capacity meets just 16 percent of the data center's power requirements.Then there’s the cost. Even after incentives, the St. Louis solar array will have a 20-year return on investment.
Investing in On-Site Generation
That math illustrates the challenges in making renewable energy work at the scale and cost required by data centers. But Emerson is among a small group of data center providers that are investing in on-site generation of renewable energy, largely out of the conviction that renewable energy will eventually play a larger role in powering data centers.
A larger number of data centers are seeking to procure renewable energy from their local utility. But the mix of renewables available from power companies varies widely from state-to-state, and many key data center markets rely on coal-powered electricity for the largest percentage of their power.
Some energy experts assert that the best way to reduce data centers' impact on the environment is to make them more efficient by implementing best practices in their design and operations, a strategy that is readily available, can be implemented now and offers a rapid return on investment.
Efficiency as the 'Silver Bullet' Solution
"Our take is that the greenest kilowatt hour is the one that’s never used," said Gregg Dixon, the senior vice president of marketing at EnerNOC, which helps large power users manage their demand.
"That's the silver bullet aspect of energy efficiency," Dixon said at a panel on renewable energy at the Uptime Institute Symposium in May. "It’s greener than solar or wind, because you just don’t use the energy at all. Everybody’s looking at the shiny new things, and that’s wind and solar. We have to start with energy efficiency."
i/o Data Centers is investing in a huge rooftop solar array at its Phoenix ONE data center, which will be paired with a thermal storage system to help the company manage power costs. Anthony Wanger, the president of i/o Data Centers, says that while the company sees a role for solar power, the benefits of improved efficiency are compelling in the short term.
"One could make the case that anything you do to digitize a process is incredibly efficient," said Wanger. "If you take 1 million pieces of mail and distribute that media electronically, you save a lot of carbon. I think digitizing these processes is the best way to get a handle on this issue."
Articulating the Industry's Carbon Reduction Story
Wanger says the data center industry is under growing scrutiny on its energy use because it hasn't explained its efficiency story and the societal benefits. In effect, the shift to digital takes energy usage that is widely distributed, and concentrates those workloads in facilities operated by the company's largest technology firms.
"I used to think this was the greatest story never told," said Wanger. "Now it’s the greatest story told a little. We are pulling efficiencies out of the off-line world in virtually every category. I think that as an industry, we have to continue to make the case to business leaders."
Pressure From Greenpeace
Pressure on data centers is mounting as environmental groups focus their attention on the sector. Earlier this year Greenpeace International blasted Facebook, saying the company should rethink plans for its new Oregon data center because it is using power from a utility that generates a majority of its power from coal.
Greenpeace subsequently called out Google, Apple, Microsoft and Yahoo as well. Although all these companies have made extraordinary gains in overall data center efficiency, Greenpeace has maintained a singular focus on the use of renewable energy, either through on-site generation or by choosing locations where electricity is sourced from renewables.
Some in the data center field say that energy sourcing is part of a bigger picture that Greenpeace is largely missing or ignoring. But some industry veterans warn that claims of being misunderstood are rapidly approaching their expiration date.
"We as an industry have a target on our back," said Ken Brill, founder of the Uptime Institute, at the group's May symposium. " We do save energy in other parts of the company, but those savings are diffuse. Unless we can explain it better, we’re going to have challenges ahead."
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