The techno-economic analysis of hybrid coastal and offshore ocean energy system for the smart charging of cross-harbour zero-emission ferries and electric vehicles

The rapid growth of electrified transportation has driven increased investment in energy efficiency and electrification, presenting a sustainable opportunity. While ocean renewable energy for electric vehicle charging and building applications has gained traction, there is scope for further exploration of renewable energy for electric transportation and improved energy management systems. This study investigated the techno-economic-environmental performance of a hybrid ocean energy system that integrates the electric ferry and offshore platform charging for shipboard electric vehicles between Macau and Hong Kong. The objective is to assess the effects of implementing the vehicle-to-charging station (V2C) function and developing energy flexibility control strategies for the hybrid system connecting two harbour cities. The findings demonstrate significant improvements across 125 cases. Technically, flexibility control in the non-dominated Case B reduces grid energy input from 4 to 1.5 million kWh and improves energy matching from 0.624 to 0.649 with V2C function activation. Economically, the annual operational cost has been reduced by 60 %, from 6.49 to 2.63 million HKD, through effective demand response and peak shaving controls. The relative net present value increases by 58 %, from 28.9 to 45.7 million HKD. Environmentally, annual carbon emissions decrease significantly from 2.35 to 0.167 million kgCO_2,eq. These results highlight the effectiveness of flexibility control and V2C function in improving energy matching performance and achieving sustainability. This study demonstrates the potential of hybrid ocean renewable energy systems and highlights the economic feasibility of effective energy management in stabilising ocean renewable.