Objective This study aims to analyze the environmental and cost coefficients of photovoltaic (PV) systems during the manufacturing stage, explore their impacts on the operational economy and emission performance of ships equipped with electric and mechanical propulsion systems, and determine the optimal PV system capacity.

Methods Taking the near-shore cruise ship MS Birka Gotland operating in the Baltic Sea as the research object, a mixed-integer linear programming （MILP）model targeting minimum operational cost was established. The initial investment cost of the PV system was obtained from the international PV price database, and the emission coefficients were calculated by combining literature data with the GREET software developed by Argonne National Laboratory (USA). By adjusting the PV capacity, the changes in equipment power output, economic indicators, and emission indexes were analyzed.

Results The PV system has a more significant effect on power output regulation of the mechanical propulsion system, but it shows better improvements in economic performance (e.g., net present value, internal rate of return) and pollutant (GHG, NOx, SOx) emission reduction for the electric propulsion system. The optimal PV capacities for the two propulsion systems are 133 kW and 266 kW, respectively, which are applicable to near-shore cruise ships.

Conclusions The PV system has prominent integration advantages in the ship electric propulsion system, and the research method adopted can provide a solid theoretical basis for the design of PV systems for different ship types.