4 Shades of Efficiency

1: Choose Smart Product Designs

Demand high-efficiency products when you write requests for proposals for your data center. It’s easier to do than you might think.


Your best bet is to look for guidance from the Green Electronics Council’s EPEAT program — the Electronic Product Environmental Assessment Tool — at www.epeat.net. EPEAT products have reduced levels of cadmium, lead and mercury, which means they’re healthier to use and less taxing on the environment. They also are more energy efficient (which reduces emissions of climate-changing greenhouse gases) and easier to upgrade and recycle.

Currently, the Federal Acquisition Regulation covers only desktop and notebook PCs, monitors and other office equipment — not the bulk of products found in data centers. But that is likely to change: The Environmental Protection Agency has begun crafting specifications for enterprise servers that would merit the Energy Star designation. In the future, EPA hopes to develop Energy Star specs for data storage and networking equipment, as well.

In the meantime, EPEAT details the environmental impact of specific products and offers RFP templates for the eco-conscious buyer.

“We just finished a survey of federal purchasers, and overwhelmingly they said that the EPEAT tool made it easier to buy environmentally friendly products without adding costs,” says Sarah O’Brien, EPEAT outreach director for the Green Electronics Council in Portland, Ore. “Before this, they were struggling with ways to find green specifications. Electronics are very complex, with hundreds of components and dozens of environmental impacts along the supply chain. EPEAT helps them prioritize.”

Buyers can choose EPEAT-certified products based on 51 criteria. There are three levels of EPEAT certification: bronze, silver and gold. If you want to have the greatest impact, go for the gold. As of early spring, 51 of 555 notebooks, desktops, integrated systems and monitors had nabbed gold designations. That means that in addition to 23 required criteria — including reporting the amount of mercury used in light sources and elimination of certain flame retardants — the gold products met 21 of 28 optional specs. These include, for example, using batteries free of lead, cadmium and mercury, and housing large plastic parts free of PVC.

2: Know Your PUE

To make your data center more energy efficient, you need a baseline measurement from which to gauge improvements. To that end, green-minded IT experts suggest using the Power Usage Effectiveness metric. The PUE can help data centers estimate their energy efficiency, compare themselves with other data centers and determine where to make adjustments.

To calculate the PUE, a center must divide its “total facility power” (all electricity that supports the data center, including the overhead lights, the servers and air conditioning) by the “IT equipment power” (servers, desktops, networking equipment and storage devices, for example).

The ideal PUE rating is 1.0, which is earned when all the energy delivered is used for computing purposes. In reality, data centers typically have PUE ratings closer to 3.0, meaning that the center consumes three times the energy needed for the IT equipment alone, according to The Green Grid, an IT advocacy group in Beaverton, Ore. (www.thegreengrid.org).

Centers can also use the PUE to determine the total energy needed to run specific equipment. For example, if the data center has a PUE of 3.0 and a server demands 500 watts to operate, then the total energy demand of the server is 1,500 watts (3 x 500).

How does all of this relate to your data center’s electricity bill? In most instances — but not all — the utility company’s bill reflects not only your overall consumption but the number of kilowatts demanded during peak hours. So, shifting your data center’s consumption to off-peak times usually will save significantly.

Want to start saving energy? Assess the energy consumption of your data center using the Lawrence Berkeley National Laboratory’s online self-benchmarking guide: hightech.lbl.gov/documents/DATA_CENTERS/Self_benchmarking_guide-2.pdf.

3: Cool Things Down

In many data centers, cooling devices — air conditioners, chillers and pumps — consume 50 percent or more of the electricity demand for the room. Room layout, cooling-unit efficiency and the number of heat-producing devices all affect the energy draw and commensurate cooling demand.

Data centers don’t have to be meat lockers. Manufacturers typically suggest ambient temperatures of between 35 and 104 degrees Fahrenheit.

“It is a fact that data centers by design are grossly over-provisioned in cooling,” says Ken Baker, data center infrastructure technologist for Hewlett-Packard. “That’s because in a distributed computing architecture, many administrators will deploy a single server for a single application. When you size air conditioners, you build the air conditioning to match the maximum load of the server. But that’s never attained. So, while the servers are grossly underutilized, all this excessive air conditioning is pumped in.”

Baker suggests installing cooling equipment that senses heat produced by each system and then adjusts the temperature accordingly.

4: Reduce Energy Consumption

There are many ways to dial back energyuse — from the choice of microprocessors in servers to the layout of the data center — without decreasing productivity. Each improvement has exponential benefits because the less energy consumed, the less heat produced; and the less heat produced, the fewer energy-consuming cooling devices needed.

Start first with microprocessors. Shifting to multiple-core microprocessors can save energy right off the bat. Multiple-core processors contain two or more processing cores on a single die; they run at slower clock speeds and lower voltages than single-core chips but handle more work.

Look for features such as dynamic frequency and voltage scaling. These let microprocessor frequency or voltage ramp up or down to more closely match demand, according to EPA. When usage is low, clock speed will decline, which reduces energy consumption.

Choosing an energy-efficient server requires some work. Because there are not yet Energy Star designations for servers, agencies must rely on the manufacturer’s energy-consumption ratings. “We find often the real steady-state usage is about 70 percent of this, but for planning purposes, go with the published data,” says Kem Clawson, chief technology officer of EMC’s federal division. “I find it best to do this for the complete solution.”

There’s a catch with that approach, however. One server may consume fewer watts but cannot handle the necessary workload. “So, what’s better?” asks Clawson, “Server A, rated at 550 watts consumption, or B, at 950? Server A sounds better until you learn it would take three of Server A to get the job done, but that we could use a virtual server and run three guest systems on a single Server B. Now what’s better: A, at 3 x 550, or B, at 1 x 950?”

 For additional ways to green your data center, click here.