An experimental wind farm project that has been on hold for more than a year is due to restart. Xcel Energy’s 1MW sodium-sulphur battery bank in Minnesota, US, was put out of action amid safety fears when a similar battery caught fire in Japan.
Fear of a similar fire meant the $4.7 million sodium-sulphur battery bank, and others made by Japanese firm NGK Insulators, were shut down in September 2011.
The cause of the fire was found to be a faulty cell that had leaked molten material and triggered a short-circuit. The battery at the site in Minnesota experienced no problems in its two-year working history and is due to be operational again in February 2013.
When the site is operational again it can continue the long-term trial of the viability of wind energy storage. The site has 20 50kW battery modules capable of storing 7.2MWh of electricity.