Energy storage system and control method

The present invention relates to an energy storage system and controlling method of the same reducing power consumption and increasing inverter efficiency by providing a plurality of inverters in parallel and selectively driving inverters according to power requirements of the load. The energy storage system of the present invention supplies power to a load by connecting the power generation system to a grid, and the system includes a plurality of inverters connected in parallel converting direct current voltage output by the power generation system into alternating current voltage of the grid; a plurality of switches respectively separately connected in correspondence with the plurality of inverters; and a controller controlling turn on/off of the plurality of switches and driving at least one of the inverters connected to each switch.