Economic and environmental comparison between diesel-electric and mechanical propulsion plants for a small cruise ship

The paper reports an economic and environmental comparison between diesel-electric and mechanical propulsion plants, employed as an alternative to the other one, to the propulsion of a small cruise ship, also described in a previously authors article. The plants prime mover are two versions of the Rolls-Royce Bergen marine diesel engines, employed one as an alternative to the other in all the considered propulsion plants. The engines are characterized by similar rated power but with different power lint curves and specific fuel contours trend in the operating diagram. The diesel-electric propulsion plants are simulated considering the diesel generators working in both constant and variable speed. The economic and environmental (by EEDI and CII index) comparison results, between the considered ship propulsion plants, are presented in tabular and graphical form and commented.