David Dunn is Senior Vice President of Marketing and Business Development for CoreSite, which operates more than two million square feet of wholesale data center and colocation space.
Approximately half of the nation’s electricity consumption comes from office and industrial buildings. Given the rising costs associated with direct and indirect energy consumption, it's imperative that the public and private sectors focus on overall energy consumption and efficiency benchmarking. Data centers and their associated electrical consumption continue to grow as communications, information processing and storage demand increase rapidly. In 2006, the Environmental Protection Agency (EPA) estimated that data centers represented approximately 1.5 percent of the United State’s total electrical demand (to the tune of $4.5 billion) and that the combined data center consumption could double by 2011.
Given the rising energy consumption of data centers, the EPA sought to establish an Energy Star rating for this relatively new real estate asset class. In 2007, the federal agency collected data from 120 participating data centers. The sample ranged in size, location, and whether or not the data centers were stand-alone or within multi-use facilities. Just this month, the EPA approved an annual Energy Star label for data centers using Power Usage Effectiveness (PUE) as its primary metric.
How Energy Star Works and How It’s Measured
The annual Energy Star rating is based on a scale of 1 to 100 (with 100 being most efficient), benchmarked to similar buildings. Thus, a data center with a rating of 50 is in the 50th percentile for data centers or performs better than 50 percent of all similar buildings. To earn an Energy Star rating, a data center must earn a score of 75 or higher.
The EPA selected the annual PUE metric as the method for determining efficiency. PUE is the most cited and best current single data point to use in benchmarking data center efficiency. As many people already know, PUE is broadly defined as "total facility energy divided by IT load" and generally runs between 1.4 and 3.0 (the lower the better, all else being equal).
Many people disagree as to what energy should be included in the numerator and the denominator, so it’s important to at least measure the data points that the EPA will use in calculating PUE. The EPA defines "total facility energy" as all of the energy delivered to a building, from all fuel sources. Further, the EPA defines "IT load" as the output of the UPS. Fortunately, both of these data points are typically easy to track as everyone receives a power bill (it's definitely a question as to whether someone in IT actually sees the power bill, but that’s another issue) and UPS units typically have built-in consumption meters. Also note that to earn an Energy Star rating, you must submit annual data through their portal. Monthly reports or snapshots won't cut it.
Hype or Help?
The Energy Star program, a joint venture between the EPA and DOE, claims to have saved Americans approximately $17 billion on their utility bills since the program’s inception. That's pretty impressive. However, as of 2009, less than 4,000 buildings (across the country) were Energy Star certified. It remains to be seen whether or not data center users and providers will embrace Energy Star ratings, but should we?
I believe that we should. We all share a common goal (utility providers notwithstanding): reduce energy consumption given a constant level of output. An effective way to initiate this change is to introduce measurement and competition. The Energy Star rating does both.
First, to earn a rating, you must measure data. Measurement forces a data center manager to know where they stand on UPS and total energy consumption. Monitoring data over regular intervals may show design flaws or poorly functioning equipment, which can lead to a long-term reduction in consumption.
A second benefit is that the Energy Star program introduces competition. For example on light bulb packaging, for years the Energy Star certification has been a third-party stamp of efficiency and can lead to differentiation and higher margins on products designed more efficiently. How do you stack up to peers or competitors in the industry? These questions can now be more readily answered. The Energy Star website even has form press releases to help companies beat their respective chests.
The program isn’t without some significant flaws though. The most notable of which, I believe, lies in using PUE as a single efficiency metric. Nearly all data centers become more efficient as overall utilization of the systems increase. All else being equal, if you reduce your IT load, it’s likely that your PUE will increase. A data center or IT manager incentivized to earn an Energy Star rating or attain the lowest PUE may not do all they can to reduce the IT load of the data center, even when a reduction in IT load will result in a lower overall consumption of energy.
As we weigh the benefits of actually having a standard against the costs of using an imperfectly designed standard, I come down on the side of having a standard. Not all will be satisfied, and not all will make decisions or care about the Energy Star rating. But if we are able to reduce some portion of energy consumption as a result, isn't it worth it?
Please check out www.energystar.gov for more information.
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