Optimal retrofitting of a hybrid propulsion system using NSGA-II algorithm for trailing suction hopper dredger

Traditional trailing suction hopper dredgers (TSHDs) are generally equipped with diesel engines as single power source. The diesel engines must be sized to cater for the maximum power demand, so they are significantly oversized most of the time. To solve this problem, an optimal retrofitting concept is proposed for matching main power equipments in hybrid propulsion system for a TSHD. The nondominated sorting genetic algorithm II (NSGA-II) is adopted to optimize the hybrid propulsion system design. Power equipments here include main engine, Variable Speed Drive (VSD), battery bank. The optimization is concerned with minimization of total installation weight and fuel consumption, also with limiting the value of State of Charge (SOC) by using graduated system of punishment. The different solutions are reflected in final Pareto front.