Increased fuel efficiency in ship LVDC power distribution systems

The benefit of having an energy storage onboard an Offshore Supply Vessel (OSV) is investigated in terms of fuel saving. Seven different operational modes with different loading profiles have been introduced for the vessel. The ship uses an LVDC distribution system to share power among sources, and distribute power among different loads. To simulate this hybrid electric power system, a nonlinear programming method is used to identify the optimal power sharing criteria between generators and the energy storage. The control strategy is based on the diesel generators loading level, which is implemented in MATLAB®. A comparison is made by counter posing the simulation results of the ship power system, before and after using the energy storage. The simulation results show improved fuel consumption in the hybrid electric system for all operational modes, particularly for dynamic positioning and harbor modes.