Method for simultaneously optimizing ship route and speed with emission control areas

THE International Maritime Organization (IMO) has delineated several Emission Control Areas (ECAs), where ships must use more expensive low-sulphur fuel. To minimize total navigation costs, shipping companies should optimize both route and speed for any shipping event. There have been many studies on this topic, which have optimized route and speed separately. These studies can be divided into two categories according to route optimization strategy: cell-based and cell-free. The cell-based approach limits the searching direction, as the cell shapes are fixed; the cell-free approach cannot identify the time points when entering and leaving ECAs. This study proposed an improved cell-based method that considers the ECA regulations and weather conditions to simultaneously optimize the route and speed, which can overcome the shortcomings in cell-based and cell-free approach. Finally, a computational studies and comparative analysis with some other existing methods were performed. The results show that the proposed method can effectively reduce the total costs and the ship emissions within ECAs, but might increase the total emissions of the whole shipping event.