This study presents a framework for designing and optimizing ship energy systems including weather-driven speed variability and navigation safety constraints. Navigation risks including resonance, surf-riding, and successive high-wave impacts, are calculated using five years of hourly weather data. Random speed variations (up to ±5%) are applied to a baseline speed profile to capture operational uncertainty, and safety-based speed reductions (up to 40%) are applied when required. Course changes are excluded. Treating navigation risks as constraints, operating profiles are generated for different weather conditions. For a conceptually retrofitted cargo ship, hydrogen fuel cell and battery capacities, and their power distribution, are optimized for each operating profile to minimize lifetime energy system cost and assess the effects of weather-induced power variation. Results show that speed and weather variability can significantly change power demand, requiring fuel cell capacities between 700 and 1500 kW. The most common configuration is a 1200 kW fuel cell system with 180 kWh of battery capacity, covering 39% of laden profiles, while full power coverage requires 1500 kW. Lifetime cost outcomes exhibit a 5th–95th percentile spread of −10.3% to +11.1% relative to mean cost. The results demonstrate the significant influence of weather variability on system sizing and cost.

This study introduces a novel framework of metocean prediction and ship performance models that integrate multiple layers of modeling to evaluate the environmental impact of ship emissions. It enables scenario simulations that assess a ship's performance, estimates pollutant emissions, and simulate the fate of these pollutants in the atmosphere. The study analyzes the fate of NOx, SO₂, and PM10 pollutants in the atmosphere using spatially distributed concentration maps. It provides a comprehensive approach to assessing the environmental effects of ships and their emissions and contributes to the field of environmental impact assessment. Case studies are presented to demonstrate the framework's functionalities, evaluating the interrelationships between adverse meteo-marine conditions, pollutant emissions, and resulting atmospheric diffusion characteristics.

Sustainability and energy efficiency issues, connected to the search for fuel consumption reductions and to the more and more mandatory international regulations regarding the emissions of atmospheric pollutants, are acquiring a growing relevance in shipping industry. In this context, the integration of forecasting resources for meteo-marine conditions with the capability of performing detailed ship performances simulations may give relevant contributions to improve the in service energy efficiency of ships through the use of weather routing systems. These systems are today widely used, almost in transoceanic navigation, and their effectiveness may be improved if they are utilized in integration with other energy efficiency measures and with observing systems for ship responses and encountered meteo-marine conditions. The work here reported has been developed in the context of the PROFUMO project, financed by the European Space Agency, in the framework of the IAP Artes 20 Programme for Feasibility Studies. Part of the project activities are devoted to perform numerical simulations of ship seakeeping and powering performances along Mediterranean routes, by the use of high resolution wind wave forecasts data produced by the operational service of Consorzio LaMMA. With this aim, in particular a numerical model of a real Ro-Ro ship has been constructed and the results of the numerical simulations are exploited to evaluate the potential impact of the variability of meteo-marine forecasting skills on weather routing and to estimate the potential contribution to fuel savings of meteorological route optimization at the Mediterranean scale.