Model-based efficiency and emissions evaluation of a marine hybrid power system with load profile

Abstract

In this paper, an efficiency and emissions evaluation framework for marine DC hybrid power systems is developed based on the physics- and data-based models of the power components. The proposed framework is tested under the operational profile of a real-case semi-submersible drill rig with all-electric propulsion and a suggetsed DC hybrid power system with batteries. The applied load profile, including propulsion, drilling, auxiliary, and hotel loads, shows high fluctuations, indicating the need for battery hybridization. In addition to the operational profile, the impact of the onboard power system configuration, sectionalized and common bus, on the emissions and efficiency has been studied. The results include the total energy efficiency of the ship powertrain from fuel to propulsion load and total CO2 emissions. For the considered vessel power system and operational profile, it is observed that the sectionalized bus configuration performs slightly better in terms of energy efficiency, and consequently fuel consumption and CO2 emissions.