A Liner Shipping Speed Optimization Model to Reduce Bunker Cost and Pollutants Emitted

Environmental impact has become one of the most relevant issues in liner shipping during the recent years. Maritime shipping is responsible for the 2.7 per cent of the world CO2 emissions, of which 25 per cent is attributable to container ships. This business also produces a significant quantity of sulphur, a very dangerous substance for human health, especially if it is emitted in areas next to the coast. At the same time, bunker cost represents the biggest portion of the operational cost of a shipping company. Slow steaming is a cheap and effective strategy from both save pollutants emissions and bunker cost. Moreover, it can be immediately put into practice. This report introduces a Mixed Integer Programming Model to solve the Liner Shipping Routing and Speed Optimization Problem (LSRSOP). The final goal is to find the best route and to optimize the the sailing speed of the vessel considering the Emission Control Areas and maximum transit times between ports. Two Heuristic Methods -the 2-Steps Method and the Simulated Annealingare proposed to solve big instances that would require too much running time to be solved until optimality. Both of them use a Hill-Climbing Algorithm that generates a slight different route from a given one. A Bi-Objective Function Model has been designed for instances whose the optimal solution can be found in reasonable time. It considers the operative cost of the vessel and the external cost of emissions. The results show efficient solutions that are the "golden line" between the most convenient solution for the company and the most sustainable solution.