According to an embodiment of the present invention, an energy storage system allows the number of charging/discharging operations under a condition of a real-time charge system to be restricted and predicts a load and generated amount of new generation energy to decrease a maximum power peak, thereby reducing the charge based on the amount of power. The energy storage system may comprise: a power charging/discharging part; and a charging/discharging control module. The power charging/discharging part charges and discharges power between a battery and a power line. The charging/discharging control module predicts the amount of power required for the next day depending on photovoltaic power generator installation information, weather information and load information to control the power charging/discharging operation of the power charging/discharging part.
