Major player projects can point to readiness, costs and benefits of solar power for data centers.
Water, water everywhere,
And all the boards did shrink.
Water, water everywhere,
Nor any drop to drink. The Rime of the Ancient Mariner - Samuel Taylor Coleridge
Data center managers must feel a lot like Coleridge’s Ancient Mariner when they look out the window (assuming their offices have any windows). Like the sailors on Coleridge’s journey, data center professionals are surrounded by free power from the wind, sun, water,the earth’s heat and biofuel, but none of it is usable as it exists to power the insatiable demands of the equipment inside the vessel. Despite this challenge, there have been several interesting projects regarding green energy sources. This piece in the data center energy series will explore solar photovoltaic to help determine if the technology is suitable to provide cost effective, reliable power to data centers.
Left: Engraving by Gustave Doré for an 1876 edition of the poem. "The Albatross," depicts 17 sailors on the deck of a wooden ship facing an albatross. Right: A statue of the Ancient Mariner, with the albatross around his neck, at Watchet, Somerset in south west England where the poem was written. (Link to Source - Wikipedia)
Solar powered data centers have been in the news recently primarily due to projects by Apple and Google. In an effort to build green data center, Apple’s Maiden, North Carolina 500,000 sq.ft. site is powered in part by a nearby 20-acre, 20-megawatt (MW) solar array, The site also has a 10-MW fuel cell array that uses “directed biogas” credits as the energy source. (Link to Apple Source) The remainder of the power needed for the site is purchased from the local utility with Apple buying renewable energy credits to offset the largely coal and nuclear generated Duke Energy electricity. Apple sells the power from the fuel cells to the local utility in the form of Renewable Energy Credits used to pay electric utility bills. Apple expects that the combination of solar photovoltaic panels and biogas fuel cells will allow the Maiden data center to use 100% renewable energy or energy credits by the end of the year. Several lesser known companies have also implemented solar initiatives but the news is not so widespread.
Left: Apple Maiden, NC data center site shows solar array in green (Link to Source - Apple); Right: Aerial photo of site with solar array in foreground (Link to Source - Apple Insider)
It will be instructive to follow reports from Apple to determine the cost-effectiveness of the company’s green approach. That being said, many if not most companies do not have the luxury of being able to build a 20-acre solar farm next to the data center. And most have neither the cash to invest in such projects nor the corporate caché of Apple to get such projects approved, so initiatives such as Maiden may be few and far between. Still, there’s a lot of desert land ripe for solar farms in the US Southwest. Telecommunication infrastructure may be one limitation, but California buys a lot of its electrical power from neighboring states so anything is possible.
What about solar power for sites where the data center is built in more developed areas, is there any hope? Colocation provider Lifeline Data Centers announced their existing 60,000 sq. ft. Indianapolis, Indiana site will be “largely powered by solar energy”. (Link to Source - Data Center Dynamics) Author Mark Monroe’s piece titled Solar Data Center NOT “Largely Solar Powered” thought about his solar panel installation and took a at the numbers behind this claim. Lifeline is planning to install a 4-MW utility-grade solar array on the roof and in campus parking lot by mid-2014. Author Monroe takes a swag at determining how much of the data center’s power needs will be filled by the solar array.
Assuming the site’s PUE is equal to the Uptime Institute’s average of 1.64 and taking into account the photovoltaic array’s operating characteristics (tilt angle, non-tracking), site factors (sun angle, cloud cover), etc., Monroe calculates that 4.7% of the site’s total energy and 12% of the overhead energy will be available from the solar installation. At an industry leading PUE of 1.1, the installation will provide 7% of the total energy and 77% of the overhead energy. Monroe notes that while these numbers are a step in the right direction, Lighthouse’s claim of a data center “largely powered by solar energy” is largely not based on the facts. His piece notes that even Apple’s Maiden site with 20 acres of panels only generates about 60% of the total energy needed by the site overhead and IT gear. Lifeline would need to add and extra 6-MW of solar capacity and operate at a PUE of 1.2 to operate at Net Zero Overhead.
I am curious to see hard data from these and other solar photovoltaic projects for data centers that will show hard cost, performance data and financial incentives (tax considerations, power contracts, etc.) that the industry can review to determine if solar is the right approach for their electrical power needs. Although such disclosure is unlikely due to competitive considerations, it would greatly assist the industry to help promote such green initiatives to help take the spotlight off of headlines criticizing the “power hungry monster”.
All efforts to improve industry efficiency and reduce energy consumption are steps in the right direction. Companies like Lighthouse Data Centers that don’t have the deep pockets of Apple or Google are taking steps toward the goal of Net Zero Overhead. The challenge for data center operators that initiate green energy or efficiency based projects will be to boast about these efforts to make headline grabbing claims that may not be well supported by the data. As Launcelot Gobbo tells Old Gobbo in Shakespeare’s The Merchant of Venice, “but at any length truth will out.” Green powered and energy independent are claims that need to be examined carefully to maintain industry credibility and good will or “truth will out.”