SIMROUTE: A Tool for Assessing the Emissions Mitigation Potential of Weather Routing in Short Sea Shipping

Ocean-going vessels contribute substantially to global carbon dioxide emissions, compelling effective mitigation strategies. This research investigates the potential of weather ship routing (WSR) for emissions reduction, focusing on Short Sea Shipping (SSS) in the Mediterranean Sea, bridging the gap between shipping pollutant estimation and weather routing optimization, two areas often studied independently.

The study utilizes SIMROUTE, an open-source software tool employing the A* pathfinding algorithm to optimize routes based on wave action derived from Copernicus Marine Environment Monitoring Service (CMEMS) data. SIMROUTE calculates both minimum distance and optimized routes, minimizing sailing time by considering weather conditions. This research builds upon SIMROUTE’s core functionalities by specifically quantifying the emissions reductions achievable through WSR.

WSR is formulated as an optimization problem incorporating various parameters, including vessel type, propulsion machinery, fuel type, and wave effects on navigation. Fuel consumption and ship emissions calculations are performed using a methodology inspired by the STEAM2 bottom-up approach, further incorporating the increased power required to overcome speed reductions caused by waves. Wave effects are primarily parameterized using the Bowditch methodology, recognized for its simplicity, with sensitivity analyses conducted using Aertssen’s and Khokhlov’s formulations.

Despite the limited fetch and relatively small significant wave heights typical of the Mediterranean, substantial reductions in fuel consumption and emissions are achieved through SIMROUTE simulations. This implies even greater benefits in open ocean conditions with larger wave heights, as supported by a case study of a large Pacific Ocean route demonstrating a 13.25% emission reduction. This aligns with existing literature advocating for sector-specific emissions analysis due to variations in influencing factors.

Derived from the SIMROUTE simulations’ results, it is concluded that, while emissions reductions on very short routes are modest, their cumulative effect over time, considering storm frequency and service schedules, warrants further investigation. Notably, significant emissions reductions, up to 30%, were observed for SSS routes up to 600 nautical miles. Consequently, SIMROUTE software stands out as a tool for demonstrating that there is an emissions mitigation potential in SSS routes, providing vessel-specific data demonstrating meaningful results regardless of distance covered, highlighting the value of WSR as a practical emissions reduction strategy.