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Employee checking server racks at the new data center of T-Systems, a subsidiary of Deutsche Telekom AG on July 01, 2014, in Biere, Germany.

An employee checks server racks at a data center in Germany. Worldwide, data centers use vast amounts of energy; a new report focuses on inefficiencies at United States facilities.

Photograph by Thomas Trutschel, Photothek Via Getty Images

Christina Nunez

National Geographic

Published August 26, 2014

In nearly 3 million data centers across the United States, some 12 million machines serve up the emails, web pages, and files we access online every day. They're the repositories of all our computerized information.

The high energy demand of those servers is well documented, but up to 30 percent of them are drawing power without actually doing anything.

These "zombie," or comatose, servers are among the examples of energy waste documented in a report about U.S. data centers released Tuesday by the Natural Resources Defense Council (NRDC). If those facilities were to cut electricity consumption by 40 percent—half of what is possible using the tools now available to improve efficiency—the electricity savings would amount to $3.8 billion and 39 billion kilowatt-hours, according to the report.

That's enough to power 3.5 million American homes.

Large companies such as Google, Facebook, eBay, and Microsoft are already highly efficient, a result of major resources and huge scale, but their share of electricity use is just 5 percent of total data center consumption in the United States.

"Our concern is more about the other 95 percent," said Pierre Delforge, who co-authored the new report, which focuses on corporate data centers, small- and mid-size server rooms, and firms that manage data for a variety of clients, which are called multi-tenant data centers.

Underworked Servers

One of the main ways that data centers use energy is to keep all those large, humming server machines cool. The industry has made significant progress in this area, some using upgraded systems that can generate power from waste heat or use outside air in cooler climates. (See related stories: "KPMG Captures Heat for Data Center Cooling" and "National Snow and Ice Data Center Gets Cool Makeover")

But how the machines themselves are being operated leaves a lot of room for improvement, the report finds. That millions of servers are running at only 10 to 15 percent capacity—or, in the case of zombie servers, at zero, is "one of the lesser known issues," Delforge said.

Useless servers tend to stay powered up because no one is aware of them, or no one wants to take the risk of unplugging them in case they are wanted at some point down the road. "It's like an airline flying 30 percent of its planes empty, and the rest of its fleet with an average of less than 15 percent of its seats filled," Delforge said. But as the report notes, data center managers tend not to get in trouble for keeping comatose servers online—their job is to make sure servers don't go down.

The NRDC report highlights the fact that at many data centers, the people managing the equipment are focused on keeping data secure and functioning properly. The electric bill goes somewhere else: a different department at the same company, perhaps, or to the external customer in the case of a multi-tenant data center.

Bill Tschudi, who has worked for about 15 years on data center efficiency and leads those efforts at the Lawrence Berkeley National Lab, said the larger Internet companies have made a lot of advances in recent years.

"But then you look at the rest of the market, and there's been no progress," he said, noting that smaller data centers in particular lack the resources and expertise to make significant changes. "That part of the market really needs to be reached. People are operating the way they were ten or 15 years ago, and the industry's kind of moved on since then."

Many small companies "are not even aware that their server room is a large energy hog and might be responsible for 30 to 50 percent of the entire electricity bill," Delforge said. "It's just not the top of the priority list."

Similarly, companies that outsource to multi-tenant data centers likely have no idea how electricity use factors into the bill, instead paying a flat fee for a block of server space. Most data centers are not disclosing to customers—or anyone else—how much energy they use, Delforge said.

Overcoming the "Fear Factor"

IO, a Phoenix-based multi-tenant data center provider that contributed information to the NRDC report, has designed systems that allow it to measure energy efficiency in real time.

"Energy inefficiency is money left on the table," said Patrick Flynn, group leader of applied intelligence and sustainability at IO. "Why somebody would leave it there means that there must be some nuanced barrier to adopting that change. We see that in the data center world."

Part of the barrier is a lack of insight at many facilities into just how much inefficiency there is. The industry has no agreed-upon standard for gauging how hard a server is working. Setting a simple metric for server utilization, and disclosing the figures, the NRDC report argues, would "help resolve one of the biggest efficiency issues in data centers: underutilization of servers."

At many data centers, aversion to risk can make managers wary of trying new things. "The fear factor in the data center world is that if you're operating OK now, don't change anything because you could upset the systems, and if some systems go down, then somebody's going to get fired," said Tschudi.

The NRDC recommends that data centers set common goals for efficiency among corporate executives and information technology managers alike. It also advocates for more investment in efficient equipment, pricing models that include incentives for efficiency, and more integration of renewable energy, a point also made in a Greenpeace report on data centers released in April. "This is a complex issue," Delforge said. "There is no silver bullet."

IO's Flynn said that the data center sector has been "left behind" on efficiency even as it has helped streamline other industries such as airlines and healthcare. His firm is building energy savings into its business strategy, aiming to compete by offering its clients more visibility into how much energy their servers are consuming and where they might maximize efficiency. "We've got a strategy of passing savings on to customers," he said.

Delforge echoed the idea that data centers have lagged in the productivity and efficiency that they have enabled in other sectors. "We want to make sure that this is not perceived as 'data centers are bad,' " he said. "For data centers to be part of the solution in terms of having a more efficient economy, they need to start cutting the waste in their own backyard."

The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

8 comments
Julie Mullins
Julie Mullins

Accuracy in data is the key. I see so many data center databases with inaccurate data because it's nearly impossible to accurately manage huge data centers with spreadsheets. This inaccurate data leads to a lack of knowledge and awareness of which equipment is contributing to the most energy consumption and/or waste. Sometimes equipment is using energy but not even being used for any function because it's been forgotten or lost. Barclays and McKesson are good examples of large companies taking control of this waste. They use Cormant-CS DCIM to monitor all their IT equipment and help optimize energy use for heating, cooling, humidity, etc. These companies won the Uptime Institute's Server Roundup Awards because of the amount of energy they saved from decommissioning dead servers. That energy savings translated into millions and thousands of dollars saved respectively. It's a great start for reducing energy consumption while also being an extremely beneficial practice for companies monetarily. For reference (http://symposium.uptimeinstitute.com/server-roundup). 

kashif siddiqui
kashif siddiqui

The answer to save energy is in proper capacity planning and availability management of the resources. Once the organization maps all of its resources to its business requirements and strategy, the whole scenario will change. Usually in small to medium size companies IT and business both still live in high walled silos and only bother to meet when there is someone required to blame.

Love Kumar
Love Kumar

Many of these underutilized servers would be failover support servers. Companies usually have these servers in case of emergencies like load, hardware crashes etc. but generally they sit idle doing nothing if there is no crash. I have seen scenarios in my career that companies are hosted in 2 data centers where servers in 1 data center are active and servers in other data center are sitting idle waiting for the disaster to happen to step in action.


It professionals also had bad habit to not remove waste servers just in case they are needed. These servers are not only hosted in data centers but also in companies premises and active through the year after year without removal. No one wants business loss due to hardware unavailability but it is bad.

Dan Morris
Dan Morris

I have a bunch of empty servers. Sometimes you buy a block of them, and then the client ditches you. It happens all the time. Now, with cloud servers, where you only pay when it is on, there is some impetus to shut down unnecessary servers.

(cloud servers are actually just chunks of memory and CPU, but the energy is still reserved and wasted)

Ramini Titanium
Ramini Titanium

Innovation is must in bussiness... The author is right f u were the manager the only thing u have in mind is to keep running the system... Bills is not ur problem its the owners problem. This is why popular sites are changing things bcoz their innovating. But most users didn't understand ex. Facebook messenger. Most users complains why should I install this client. For what reason we don't know but there is a good reason behind it.

Brent Seizer
Brent Seizer

Perhaps the photo at the top of the article is a stock photo.

Most data centers dont use rack mounted servers any more.  They use blade servers, and place them in rack.  50 blade servers will fit in one rack and use 1/5 of the energy and air conditioning that 6 large rack mount servers would require.  Each blade can be its own VMWare ESX server and host 20 Windows or Linux servers.  50*20=1000 servers in one rack.

To reduce electricity even more, install solar panels on the roof of the building.  It wont eliminate the need for electricity from the utility but it will reduce it.

Jakob Stagg
Jakob Stagg

Not to worry. NSA will figure out how to step up invasion of our privacy to fill all available resources.


To paraphrase Parkinson's Law: Data will expand to fill all storage space available to hold it.

Carter Fox Jr.
Carter Fox Jr.

Stop storing folks information and free up some of that storage space. then you can cut back on how many servers you need to run. Problem solved!

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