Modeling and Analysis of Ship Energy Efficiency Operational Indicator Based on the Monte Carlo Method

Water transport is commonly recognized as the most environmentally friendly form of transport, but this will be a challenge in the future as its current contribution (around 3% of global CO2 emissions) is expected to increase to around 20 - 25% of global anthropogenic CO2 emissions by 2050. Climate change and its mitigation has become the most pressing issue for the shipping industry. This study examines ship energy efficiency improvement method through a modeling analysis to a Yangtze River ship. Firstly, water flow distribution of the Chinese Yangtze River is investigated using a normal distribution evaluation and a kernel density evaluation method based on field acquired data. Then, the mechanism model of the energy efficiency operational indicator of the marine engine is developed based on the mutual relations between the hull-engine-propeller. The inverse transform method is applied to generate the sample data from the probability distribution with the water velocity and the ship speed considered as stochastic variables. Based on the Monte Carlo method, the ship's estimated energy efficiency operational indicators under different voyage conditions are obtained. Finally, through comparative analysis, it can be found that the water flow features of the Yangtze River are quite different in different areas and that the water flow has a great impact on the ship energy efficiency indicator. And the ship energy efficiency indicator is greatly dependent upon the ship voyage speed and that the energy efficiency indicator increases rapidly with increasing speed. This study can benefit shipping companies in their efforts toward energy savings and emissions reduction.