Firm Tests Wind-to-Battery Storage

MINNEAPOLIS — Regional clean energy provider Xcel Energy released preliminary results from its wind-to-battery storage project.

 

In a statement, Xcel officials said that its one-megawatt battery-storage technology works well for storing variably produced wind energy, and may also work for capturing solar, allowing both forms of energy to be released to the electricity grid during peak usage times. The project represents the first use of the technology in the United States for direct wind energy storage, according to Xcel.

 

The wind to battery project consists of a sodium sulfur battery installation connected to an 11-megawatt wind farm designed to demonstrate the storage and release to the grid of wind energy.

 

Collectively, the 20 50-kilowatt battery modules at the Luverne, Minn. site are approximately the size of two semi-trailers and weigh about 80 tons. Individually, they are each able to store about 7.2 megawatt-hours of electricity and, when fully charged, can power 500 homes for more than seven hours.

 

Preliminary test results showed that the storage project has the ability to provide a steady stream of energy, even though production of wind energy occurs inconsistently.

 

Additionally, Xcel’s testing showed the battery responded to real-time imbalances between generation and load, allowing the delivery of electricity to the grid during peak daytime hours, and energy storage taking place at night.  

 

"We have proved that this technology can perform the functions of storage that we were looking for to help us manage the variability of wind energy on our operating system," says Frank Novachek, Xcel Energy’s director of corporate planning.

 

Based in Minneapolis, Xcel began testing the wind-to-battery project in 2008. Officials at the company say it will continue to assess the technology’s ability to integrate large loads of wind energy onto the grid, with the goal of producing a final report by next summer.

 

The next phase of the study will determine the cost effectiveness of the technology. Xcel’s batteries were purchased for $4 million from Japanese manufacturer NGK Insulators Ltd.