Research on Economics of Mixed Energy Storage for Smoothing Wind Power Fluctuation with Consideration of Confidence LevelXintao XIE, Hao LI, Liqiang PAN, Shuai XIAO, Mengjiao LI and Zhenyu WUMATEC Web Conf., 232 (2018) 04055DOI: https://doi.org/10.1051/matecconf/201823204055