Maritime decarbonization requires propulsion systems that are low-emission and dynamically suitable for repeated short-route operation. This paper presents a route-inspired, time-domain power-balance assessment of proton exchange membrane fuel cell (PEMFC)-based hybrid architectures for a 1.80 m prototype catamaran. A real ferry operating context in the Suez Canal region was translated into a representative 15 min prototype operating cycle repeated over an 8 h operating window. Three cases were evaluated under the same DC-bus load basis: Case 1, PEMFC + Battery; Case 2, PEMFC + PV; and Case 3, PEMFC + PV + Battery. The PEMFC-battery calculations were based on DC-bus power balance, converter, battery-current, and SOC equations, while the PV contribution was calculated using a shipboard PV power model with PVGIS seasonal irradiance and temperature inputs. The results show that Case 1 eliminates repeated startup deficits through battery support, whereas Case 2 reduces PEMFC loading but cannot remove startup deficits without an energy buffer. Under the best seasonal PV input, July, the PV peak reached 84.88 W, and the PV-used energy in Case 2 was 399.64 Wh. Case 3 increased the utilized PV-bus energy to 450.87 Wh, maintained the final SOC at 0.90, and removed the repeated transient deficits under the adopted ideal power-balance assumptions. Therefore, the PEMFC + PV + Battery architecture is selected as the preferred configuration for the next experimental prototype phase.
In Lithuania, solar energy is expanding rapidly. In 2020, the installed capacity of solar power plants was 170 MW, and by 2025, it exceeded 900 MW. This growth reflects not only technological progress but also an increasing interest from consumers and businesses. With rising electricity consumption and more solar modules being installed, it is becoming increasingly important to analyse how technological efficiency is evolving in the Lithuanian climate and the influence of the legal framework on this process. Properly coordinated technical and legal development can ensure the sustainable and long-term advancement of solar energy. This research paper explores the interplay between legal solutions and technological efficiency in the development of solar power plants, analyses the main challenges facing Lithuania and the EU, and identifies areas that remain underexplored. Directions for further research are provided, emphasising system optimisation and long-term performance.