An energy management system of a Remotely Operated Vehicle (“ROV”) has a generating unit located in a remote station on a water body and configured to generate a generated electrical power with a first maximum value); a ROV configured to operate in the water body and configured to absorb a second maximum value of an absorbed electrical power greater than the first maximum value; an electrical energy transmission line connected to the generating unit and to the ROV; and an electrical energy storage device located along the transmission line and/or on board the ROV.