An integrated energy efficiency optimization method of the wind-assisted hybrid ship for the shipping decarbonization.

The utilization of wind energy can provide auxiliary thrust and hence reduce the fuel consumption as well as carbon dioxide (CO2) emissions of wind-assisted ship. However, the use of sails would deviate main engine (ME) from its optimal operating point, which would reduce the engine fuel efficiency. The adoption of the shaft generator (SG) can maintain the ME running at the optimal fuel efficiency point in this condition. However, it is crucial to achieve the integrated optimization of the sailing speed, route, sails' angle of attack, and SG output power (SG-OP) to enhance the wind-assisted ship energy efficiency. Therefore, an integrated energy efficiency optimization method is proposed for reducing the ship fuel consumption. The results reveal that this method can effectively increase the energy efficiency of the wind-assisted hybrid ship, decreasing fuel consumption and energy efficiency operational index (EEOI) by about 5.25 % and 7.36 %, respectively.