Power take-off co-design and LCoE reduction of a hinged-type wave energy converter using a genetic algorithm

This paper addresses a power take-off (PTO) co-design problem of a wave energy converter (WEC), which is vital for the reduction of the levelised cost of electricity (LCoE). A genetic algorithm (GA) is employed to resolve this problem, with significant advantages over traditional methods. A hinged-type multi-float WEC M4 with an electrical drive train as its PTO is considered as a case study. Two key parameters for PTO design, the mechanical gearbox ratio and the generator rated torque, which have great impacts on both power capture of the WEC and the cost of the PTO, are selected as the co-design optimisation variables. The effectiveness of the proposed GA-based co-design approach is demonstrated, and its efficiency is quantified. Simulations using real sea data show that the proposed approach yields an optimal solution with significantly reduced LCoE. The proposed approach also has remarkably reduced computational load, approximately 1/3 compared with a benchmark line search method. The benefit of LCoE reduction can be more significant if more design parameters are considered. It is also found that up-scaling the WEC capacity also contributes to LCoE reduction. From 10 kW to 1 MW WEC capacity, LCoE can be reduced by a factor of 6. • Heuristic algorithm resolves practical PTO co-design for a wave energy converter. • Genetic algorithm is much more e icient than the traditional line search method. • Design parameters for maximum power capture di er from those for minimum LCoE. • Upscaling of WEC capacity can further benefit LCoE reduction of WECs.