Duke Energy to Deploy Energy Storage Technology at Texas Wind Farm

CHARLOTTE, N.C., April 14, 2011 /PRNewswire/ -- Duke Energy (NYSE: DUK) intends to store electricity generated at its Notrees Windpower Project in west Texas using an energy storage and power management system developed by Austin-based Xtreme Power.

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In November 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-megawatt (MW) Notrees wind farm, located in Ector and Winkler counties. After due diligence, Duke Energy chose Xtreme Power (www.xtremepower.com) to design, install and operate a 36 MW-capacity Dynamic Power Resource™ system at the wind farm. When complete, the battery storage system will be one of the largest of its kind in the world.

This system will store excess wind energy and discharge it whenever demand for electricity is highest – not just when wind turbine blades are turning. In addition to increasing the supply of renewable energy during periods of peak demand, Xtreme's Dynamic Power Resource™ solution will help stabilize the frequency of electricity traveling throughout the power grid.

Duke Energy will work closely with the Energy Reliability Council of Texas (ERCOT) to integrate the wind power and battery storage solution into the state's independent power grid. The Electric Power Research Institute (EPRI) will advise the project team, collect data and help assess the potential for broader adoption of energy storage solutions throughout the industry. Results from the storage project at Duke Energy's Notrees wind farm will be shared publically through the DOE's Smart Grid Information Clearinghouse.

The DOE grant was made possible by the American Recovery and Reinvestment Act of 2009. In January 2011, DOE and Duke Energy agreed upon the terms and conditions of the grant. Duke Energy will elect to receive the matching funds for the energy storage and management solution once the company has completed its due diligence.

Duke Energy is targeting an in-service date for the battery storage system by late 2012.

About Duke Energy Renewables

Duke Energy Renewables, part of Duke Energy's Commercial Businesses, is a leader in developing innovative wind and solar energy solutions for customers throughout the United States. The company's growing portfolio of commercial renewable assets includes nine wind farms and four solar farms in operation in five states, totaling approximately 1,000 megawatts in electric-generating capacity.

Headquartered in Charlotte, N.C., Duke Energy is a Fortune 500 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 Xtreme Power

Based in Kyle, Texas, Xtreme Power engineers, manufactures and operates large-scale digital power systems for use in renewable energy and micro-grid applications. Xtreme's Dynamic Power Resource™ combines the energy storage capabilities of the company's proprietary PowerCell™ technology with its micro-second controls and high-efficiency power electronics, creating a comprehensive solution to the intermittency and variability challenges facing utilities and independent power producers looking to implement clean energy to the electrical grid. By providing scalable systems engineered specifically to the needs of its customers, Xtreme Power offers a safe and cost-effective approach to dramatically increase the feasibility of renewable energy. Xtreme Power is backed by investors SAIL Capital Partners, Bessemer Venture Partners, The Dow Chemical Company, Fluor Corp., BP Alternative Energy, Dominion Resources, POSCO ICT, SkyLake & Co. and Spring Ventures, LLC.

SOURCE Duke Energy