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The Little Secrets Behind Apple’s Green Data Centers

Apple is using a combination of solar, fuel cells, and renewable energy purchases to meet its clean-energy targets.

Apple this week said that all of its data centers are powered by renewable energy. How Apple achieved that impressive goal reflects the complexity of transitioning to renewable energy. 

Anchoring Apple’s flagship green data center is 10 megawatts worth of gas-powered fuel cells. Credit: Apple.

In its annual environmental footprint report, Apple detailed how its U.S. data centers—the computing centers that serve up Apple’s online services—can claim to be powered by “100 percent renewable energy.”

Its flagship project is the Maiden, North Carolina data center, which has a sprawling 20-megawatt solar array nearby, due to be completed this year. But data centers need so-called baseload power that can deliver power at all times of the day, as well as back-up reserves in the case of a grid outage.

To achieve that, Apple has installed 10 megawatts of fuel cells, the largest non-utility generation plant. The fuel cells, from Bloom Energy, convert natural gas to electricity. Because Apple is purchasing biogas credits from another company, it can claim that the data is run from renewable sources. Biogas is the gas captured from decaying landfills or animal waste. (See, Apple Data Center Does the Fuel Cell Industry a Huge Favor.) 

Similarly, Apple is purchasing renewable energy from the wholesale energy markets at its other data center locations, including wind from the local grids in Oregon and California. Its first priority is to generate renewable energy on site, but when Apple doesn’t, it will purchase it from outside providers, according to its environmental report.

Worth watching is the mix of energy sources at Apple’s planned Reno, Nevada data center. There is ample solar energy but Apple also plans to tap Nevada’s geothermal resources, which can provide baseload power. That combination could result in a self-powered renewable energy data center.

While clean, renewable energy gets most of the attention, Apple likely spent at least as much engineering effort to make its data centers very energy efficient. The Maiden facility, for instance, has massive cold water storage tanks that allow its chillers to reduce peak-time energy demand, saving energy and Apple higher power chargers. It also has precision air flow handlers to minimize energy use and the facility will use outdoor air for cooling most of the time. Chilling typically represents about half of a data center’s energy use.

In an interview with Bloomberg, Apple’s chief financial officer Peter Oppenheimer said that, “We think these efforts will result in learnings that other companies and communities can benefit from as well.” 

In the case of using large-scale fuel cells combined with on-site solar, this is certainly true. Data center operators are, understandably, risk averse and breaking with traditional energy approaches—grid power and back-up diesel generators—will take leading companies with ambitious corporate goals to demonstrate whether alternatives are effective.