Duke Energy Renewables completes Notrees Battery Storage Project in Texas; North America's largest battery storage project at a wind farm

CHARLOTTE, N.C., Jan. 23, 2013 /PRNewswire/ -- Duke Energy Renewables, part of Duke Energy's Commercial Businesses, announced today the completion of its 36-megawatt (MW) energy storage and power management system at its Notrees Windpower Project in west Texas. The system completed testing and became fully operational in December, 2012.

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"Battery storage is an important innovation to address the variability of wind and solar energy generation," said Duke Energy Renewables President Greg Wolf. "Developing an expertise in this advanced technology will enable us to expand the use of renewable energy, better integrate it into the power grid and become even more efficient at serving our customers."

In late 2009, Duke Energy announced plans to match a $22 million grant from the U.S. Department of Energy (DOE) to install large-scale batteries capable of storing electricity produced by the company's 153-MW Notrees wind farm, located in Ector and Winkler counties. The grant was made possible by the American Recovery and Reinvestment Act of 2009.

"Completion of this project represents a singular success for Duke Energy, for the DOE, and for the entire energy storage community in the U.S.," said Dr. Imre Gyuk, program manager for energy storage at the U.S. Department of Energy. "It will demonstrate the capability of energy storage to mitigate the variability of wind energy and to contribute to the stability of the grid."

Austin-based Xtreme Power designed and installed the 36 MW-capacity Dynamic Power Resource™ at Notrees and will continue to operate the system. The battery storage project will help mitigate the variability of wind power, storing excess wind energy and discharging it whenever demand for electricity is highest.

In addition to increasing the supply of renewable energy during periods of peak demand, the system will help stabilize the frequency of electricity traveling throughout the power grid. Duke Energy is working closely with the Energy Reliability Council of Texas (ERCOT), which signals to the battery storage system to either dispatch stored energy to increase frequency or absorb energy to decrease frequency.

The Electric Power Research Institute (EPRI) will collect performance data from the battery storage system and help assess the potential for broader adoption of energy storage solutions throughout the industry. Technical and economic data will also be analyzed for DOE by Sandia National Laboratory. Results from the storage project at Notrees wind farm will be shared publically through the DOE's Smart Grid Information Clearinghouse.

About Duke Energy Renewables
Duke Energy Renewables, part of Duke Energy's Commercial Businesses, is a leader in developing innovative wind and solar energy generation projects for customers throughout the United States. The company's growing portfolio of commercial renewable assets includes 15 wind farms and 14 solar farms in operation in nine states, totaling more than 1,700 megawatts in electric-generating capacity. Learn more at www.duke-energy.com/renewables. Headquartered in Charlotte, N.C., Duke Energy is a Fortune 250 company traded on the New York Stock Exchange under the symbol DUK. More information about the company is available on the Internet at: www.duke-energy.com.

About DOE ARRA Storage Projects.
DOE's Office of Electricity Distribution and Energy Reliability (OE) has the mission to lead national efforts to modernize the electric grid, enhance security and reliability of the infrastructure, and facilitate recovery from disruptions to energy supply. As part of this mission, OE has awarded 16 grants for energy storage projects under the American Recovery and Reinvestment Act of 2009 (ARRA) for a total of $185M. Each project is at least 50% cost shared. The projects cover diverse technologies such as compressed air energy storage, flywheels and advanced batteries. Applications include frequency regulation, smoothing of a photovoltaic installation, ramping for wind, and time shifting for a fossil fuel plant. ARRA projects are an integral part of OE's Energy Storage Program. Project management is provided by the National Energy Technology Laboratory (NETL).

About Xtreme Power
Founded in November 2004, Xtreme Power designs, engineers, installs, and monitors integrated energy storage and power management systems for Independent Power Producers, Transmission and Distribution Utilities, and Commercial & Industrial End Users, among others. Xtreme Power's technology delivers on its promise to solve complex grid challenges and our customers rely upon our staff of over 100 power systems engineers and professionals to design and implement a solution specific to each customer's need.

Xtreme Power is a privately held company and has raised in excess of $90 million since its founding. Current investors include SAIL Capital Partners, Bessemer Venture Partners, The Dow Chemical Company, BP and Fluor, among others. These multimillion-dollar investments have yielded tremendous growth and accolades, including the following: Bloomberg 2012 New Energy Pioneer Award, R&D 100 Award, one of 4,000 companies selected for the Global Cleantech 100 Award, and most recently honored by Inc. Magazine as the 15^th fastest growing company in the nation. For more information, please visit http://www.xtremepower.com.

SOURCE Duke Energy