The utility is testing 20 such batteries with an 11-megawatt wind farm in southwestern Minnesota. There’s a test phase set for this spring and then the batteries are expected to go online in October.
The challenge with wind power, explained an Xcel Energy representative, isn’t that it blows and stops but that the speed of the wind varies. So the system will work like this: When the wind is blowing, the spinning turbines will help charge the batteries. When the wind slows, the batteries will help even out the flow of electricity to the grid. The batteries discharge one megawatt of power, which is enough energy to power about 1,000 homes. The Japanese-made batteries have a life expectancy of 15 years.
This is the first time a utility has used batteries in conjunction with a wind farm to help with peak power demands. By 2020, Xcel Energy is required by Minnesota to get 30 percent of its energy from renewable sources.