The International Journal on Marine Navigation and Safety of the Sea Transportation

The study presents a comprehensive comparison among traditional marine fossil fuels and seven alternative unconventional solutions: fossil-based fuels (natural gas (NG) and methanol), biological (HVO, bio-NG, and bio-methanol), and synthetic fuels (NG and methanol). The comparison evaluates technical, economic, and environmental aspects. The case study focuses on the mechanical propulsion system performance of a small luxury passenger ship, simulated by using a mathematical model developed in a Matlab-Simulink environment. In the simulation, the ship's original engines have been replaced with alternative engines of comparable power and RPM, which are compatible with the fuels under consideration. In addition to GHG evaluation, the study uses International Maritime Organization parameters such as the EEXI and the CII to assess the environmental impact of fuels. From an economic perspective, the vessel’s propulsion system has been evaluated based on CAPEX and OPEX indices, providing a holistic view of the feasibility and sustainability of each fuel option.