S&C Electric Installs Smart Grid Storage Management System For Xcel Energy Wind-to-Battery Project

March 19, 2009 by Jeff Shepard

Integrating variable wind and solar power production with the needs of the power grid is an ongoing issue for the utility industry. Xcel Energy has begun testing battery-storage technology that captures wind energy and moves it to the electricity grid when needed. This is said to be the first U.S. application of the battery as a direct wind energy storage device.

S&C Electric Company was contracted to install the battery along with the S&C Smart Grid Storage Management System™ (SMS). The SMS is a fast-response automatic controller that interfaces between the stored energy system and the utility, providing the ability to store energy in a battery storage system, and to control the discharge of power when required. It can address such issues as intermittent power production with production peaks and valleys, VAR control on generation, SCADA control of wind production, and improved integration of wind generation into the standard generation production schedule. For example, SMS can store wind power during periods of high output. The stored power can then be used for a variety of purposes, including peak shaving, establishing a distributed power grid during a general outage, energy arbitrage, or power quality improvement.

"Energy storage is key to expanding the use of renewable energy," said Dick Kelly, Xcel Energy Chairman, President and CEO. "This technology has the potential to reduce the impact caused by the variability and limited predictability of wind energy generation."

The 20 50kW battery modules will be roughly the size of two semi trailers and weigh approximately 80 tons. They will be able to store about 7.2 MWh of electricity, with a charge/discharge capacity of one megawatt. When fully charged, the sodium-sulfur battery will potentially power 500 homes for over seven hours. When the wind blows, the batteries are charged. When the wind calms down, the batteries supplement the power flow.

The project is located in Beaver Creek, Minnesota, about 30 miles east of Sioux Falls, South Dakota. The battery installation is adjacent and connected to a nearby 11-MW wind farm owned by Minwind Energy, LLC.