Lithium ion battery maker A123 Systems today said it will supply an energy storage system attached to a wind turbine in a test that could lead to further grid business in China.http://news.cnet.com/8301-11128_3-20083142-54/a123-scores-battery-deal-for-wind-power-in-china/
Wind Turbine does not provide constant and controllable supply of electricity and that is why grid needs energy storage in order to be fully able to utilize wind power.