In this book, various problems of wind power and energy storage under market environments have been resolved. In deregulated industry, the electricity market was divided into submarkets for different services: (1) Markets for energy services and (2) Markets for frequency control. Accordingly, the economic operation of independent Battery Energy Storage System (BESS), and then combined Battery Wind Generation Systems (BWGS) in a real-time market have been presented. In addition, we have proposed a novel scheme for BES in order to reduce the cost of wind power assuming a frequency control market.