Assessment of offshore wind and wave energy resources for combined exploitation in the East China Sea

This study explores the potential for combining offshore wind and wave resources in the East China Sea, motivated by the increasing interest in offshore renewable energy for enhancing power output and reducing intermittency and variability. The research focuses on three primary objectives: i) analyzing the spatial distribution and variation patterns of offshore wind and wave energy; ii) evaluating the correlation and complementarity between these two resources; and iii) assessing the stability of combined offshore wind and wave farms at various ratios by examining intra-annual variability, power smoothing capabilities, and downtime periods. Our analysis reveals that the Taiwan Strait has the lowest complementarity between wind and wave resources, whereas the Zhejiang coast exhibits the highest complementarity. The suggested best areas for future combined exploitation are along the Zhejiang coast. Specifically, compared to standalone wind or wave farms, intra-annual variation can be reduced by 20–40 % with 40–70 % wind farm capacity. Additionally, the coefficient of variation can be lowered by 10–20 % with 40–50 % wind farm capacity. Furthermore, employing integrated approaches reduces downtime by approximately 10 % compared to operating wind farms independently.