Duke Energy data center testing finds DC power uses 15% less electricity than AC system

“DC-powered data centers provide increased energy savings by eliminating multiple power conversion stages,” said Omar Siddiqui, director of energy utilization research for EPRI.

Nov 30th, 2010

PALO ALTO, Calif. -- A preliminary test by the Electric Power Research Institute (EPRI - www.epri.com) of a direct current (DC) power system at a Duke Energy data center in Charlotte, North Carolina found that the system uses 15 percent less electricity than the existing alternating current (AC) power system.

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“While this is significant news for any company running a data center today, this could be especially critical for the more than 2.5 million smaller data centers across the United States that rely upon inexpensive yet viable ways to reduce costs,” said Curtis Watkins in Duke Energy’s Technology Development group. “If this DC technology was implemented in all those data centers the impact could be significant.”

The U.S. Environmental Protection Agency (EPA) reported to Congress that data center industry power consumption doubled from 2000 to 2006 and was expected to double again over the next five years. EPRI notes that if this trend continues to 2016, then reducing data centers’ energy consumption could reduce demand more than 25 billion kilowatt hours per year.

For the Duke Energy demonstration project, the data center’s 480V AC was converted to 380V DC and delivered to the equipment racks via a 380V DC bus. According to EPRI, the 15 percent energy savings provides a good benchmark for the industry because the 480 V AC system configuration is typical for data centers across the United States.

“DC-powered data centers provide increased energy savings by eliminating multiple power conversion stages,” said Omar Siddiqui, director of energy utilization research for EPRI. “Through similar circuit elimination, the data center servers are also made more efficient.”

The Electric Power Research Institute, Inc. conducts research and development relating to the generation, delivery and use of electricity for the benefit of the public. An independent, nonprofit organization, EPRI’s members represent more than 90 percent of the electricity generated and delivered in the United States, and international participation extends to 40 countries. Principal offices and laboratories are located in Palo Alto, Calif.; Charlotte, N.C.; Knoxville, Tenn.; and Lenox, Mass.

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