Xcel Energy selected GridPoint’s software platform to control the flow of power between the grid and a NGK Insulators’ sodium-sulfur battery storing wind energy. When fully charged, the one-megawatt battery will hold approximately 7.2 MWh of electricity, potentially powering 500 homes for over seven hours. This is the first U.S. application of the battery as a direct wind energy storage device.

The GridPoint Platform applies information technology to the electric grid to provide utilities with an intelligent network of distributed energy resources that controls load, stores energy and produces power. It will allow Xcel Energy to explore using real-time grid conditions and energy pricing to determine when the battery charges or discharges. Based on system regulation and pricing signals received by the software platform, the battery’s charging behavior will be adaptively controlled. When the demand for electricity is high, as an example, stored wind energy could be automatically discharged to the grid, supplementing the power flow. When demand is low, the software platform could issue commands for the battery to store the available energy.

The project will take place in Luverne, Minn., about 30 miles east of Sioux Falls, S.D., adjacent and connected to the nearby 11-megawatt wind farm owned by Minwind Energy, LLC. S&C Electric Co. will install the battery and all associated interconnection components. The battery is expected to go on-line in January 2009.

GridPoint’s software platform will also be logging performance data from the battery and associated metering equipment for analysis by the University of Minnesota, the National Renewable Energy Laboratory and the Great Plains Institute.