The collection and delivery of power through energy islands are considered to be an important mode for offshore wind power development in the future. Currently

long-distance transmission via submarine cables is associated with high cost

limited onshore access points and long fault repair time. Meanwhile

the power-to-X delivery mode by using vessels suffers from low conversion efficiency and large spatial requirements offshore. In response to these challenges

an offshore energy island power delivery technology based on electric energy storage vessels is proposed. First

a technology architecture for an electrified energy island is designed with a focus on power conversion. Next

a technical and economic evaluation method for the energy island power delivery solution is proposed

considering factors such as wind power integration

supply-demand balance

flexible delivery

and maritime transportation routes. Finally

based on the resource characteristics of a specific island in the South China Sea and its surrounding areas

the feasibility of the proposed energy island power delivery solution across different delivery distance is analyzed

and the key factors affecting the techno-economic performance of the solution are identified. The study shows that the energy transmission efficiency and the levelized cost of onshore electricity(LCOE) for electric energy storage vessel transportation strategy are negatively correlated with offshore distance and wind power capacity

while positively correlated with the storage capacity of individual vessels. When handling wind power transmission over 150 km to 200 km with an energy transmission efficiency standard of 80%

the LCOE of vessel strategy can be as low as 0.46 CNY/kWh

demonstrating better economic performance compared to three cable-based transmission methods such as high voltage alternating current(HVAC)

high voltage direct current(HVDC) and fractional frequency transmission system(FFTS).