Storing wind energy

Xcel Energy will soon begin testing a technology to demonstrate its ability to store wind energy in batteries.


Xcel Energy will soon begin testing a 1MW battery-storage technology to demonstrate its ability to store wind energy and move it to the electricity grid when needed.  Fully charged, the battery storage system could power 500 homes for over 7 hours.


The 20 50kW sodium-sulphur batteries for the project – roughly the size of two semi trailers and weighing approximately 80 tons – will be supplied by NGK Insulators. They will be able to store about 7.2MW-hours of electricity, with a charge/discharge capacity of 1MW.


The project will take place in Luverne, about 30 miles east of Sioux Falls, South Dakota, with the battery installation beginning this spring adjacent, and connected to, a nearby 11MW wind farm owned by Minwind Energy. S&C Electric Company will install the battery and all associated interconnection components.


Partners in the project with Xcel Energy include the University of Minnesota, the National Renewable Energy Laboratory, the Great Plains Institute and Minwind Energy.


The project has been selected to receive a $1m grant from Minnesota’s Renewable Development Fund, pending Minnesota Public Utilities Commission approval this spring.


The battery farm is expected to go on-line in October 2008.