A model for speed and fuel refueling strategy of methanol dual-fuel liners with emission control areas

Methanol dual-fuel (DF) liners can simultaneously use traditional fuel oil and methanol as blended fuels, which can address environmental protection requirements while ensuring economy. This paper presents an optimization model for the speed and refueling strategy of methanol DF liners. A decision-making tool is introduced for shipping companies to develop liner operation plans. A mixed-integer 0–1 planning model is constructed with the objective of minimizing the operating cost of a single voyage of a methanol DF liner, and the optimal solutions for the voyage speed in each segment and the fuel oil and methanol refueling strategy at each port are computed considering the dual-fuel mixing of fuel oil and methanol. In this paper, the validity of the model and algorithm are verified with the AEU3 route of COSCO Shipping as an example, and the results show that installing a scrubber on liners and mixing heavy fuel oil (HFO) and methanol is more economical than mixing very low-sulfur fuel oil (VLSFO) and methanol, considering the existing emission standards. The studied liner should increase its speed in emission control areas (ECAs) and refuel at ports with low prices for fuel oil and methanol. Although the above conclusions are not influenced by changes in the price of methanol, the price difference between HFO and VLSFO, or the carbon allowance price, changes in sulfur emission standards will have a significant effect on the speed and refueling strategy of liners and carbon emissions. This paper provides a theoretical reference for operational decision-making for shipping companies operating methanol DF liners and is of practical value for improving the scientific management of methanol DF liners, enhancing the energy efficiency of ships, and reducing the emission of pollutants from ships.