U.S. Department of Energy - Energy Efficiency and Renewable Energy

Wind Program

Duke Energy to Deploy Energy Storage Technology at Texas Wind Farm

April 14, 2011

CHARLOTTE, N.C., April 14, 2011-- 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 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.