© 2020 International Solar Energy SocietyMaritime transportation has a remarkable contribution to the increase of pollutant gases in the atmosphere, and adapting alternative energy systems to ship's main power grid is an effective method to both save energy and reduce the amount of emission gases. For this reason, the contribution of solar power, which is one of the effective alternative energy sources, to the marine vessels as a result of adaptation to the ship's power system and the environmental impacts of application is evaluated within the scope of the study. A novel approach is demonstrated for the layout of solar arrays within a Ro-Ro type marine vessel navigated between Pendik/Turkey and Trieste/Italy during 2018, and the performance of the designed system is theoretically evaluated. According to followed methodology, 7.76% of energy efficiency is carried out and 7.38% of the fuel requirement of the stated vessel is met by the designed solar system. 0.312 tons of SOx, 3.942 tons of NOx, 232.393 tons of CO2, and 0.114 tons of PM are prevented from releasing to the atmosphere. Besides, the investment of the solar system is analyzed under three different economic indicators and is found to be economically profitable to implement on the ship.