Application In the future, Renewable energy, such as solar and wind power, is key energy resource. Solar and Wind power are Intermittent and those changes occur imbalance of grid system. ESS can provide smoothing control of renewable power generation for stability of grid. ESS also can be essential part for off-grid solution which is consists of renewable energy. In case of Korean Large power plant, transmission and distribution infrastructure are not easily built due to many reason, such as objection of residents, political issue and large investment. Also some countries have dynamic electricity tariff systems. In these countries, ESS can save electricity cost with arbitrage operation. Countries have peak pricing will give end user more opportunities to save electricity bill with peak shaving operation. Grid regulation service market is one of value marking area of ESS application. PJM interconnection started performance based regulation in 2012. Also Korea Power Exchange started 8MW/4MWh ESS demonstration project to develop regulation market with Fast Responding resources in Korea.