Medium speed diesel generator sets and hybrid energy technologyassessing the potential reduction of exhaust gases emissions in diesel-electric propulsion systems for PSVs

Abstract

The installation of Diesel-Electric propulsion systems has increased in the marine industry. In Brazil, the number of PSVs with electric propulsion systems is growing, leading to be the standard for most support vessels. In those vessels, the common arrangement uses high-speed Diesel generator sets for power generation and induction motors driving propellers, reporting significant reductions in the fuel consumption and the exhaust emissions when compared with mechanically propelled PSVs. Nonetheless, further abatements in these parameters could be achieved by implementing other technologies for power production and the addition of energy storage in Diesel- Electric propulsion systems. In this work, the use of medium-speed Diesel generator sets and energy storage technologies in electrically propelled PSVs is analyzed. For this purpose, the fuel consumption, exhaust emissions, mass, volume and acquisition costs of four electric propulsion arrangements are estimated and compared. Two of the arrangements are equipped with medium-speed Diesel generator sets, two with energy storage devices and one with high-speed Diesel generator sets. Energy storage appears as an interesting alternative for decreasing fuel consumption and emissions by optimal loading of Diesel engines. The implementation of medium speed generator also report reductions in fuel consumption, but with the highest emissions. The arrangements with high-speed generators presented the lowest mass, volume and acquisition costs.