Joint exploitation potential of offshore wind and wave energy along the south and southeast coasts of China

There is an increasing interest in co-exploiting marine energies of various types, as it can reduce grid connection and maintenance costs and enhance electricity production. A threefold objective of this work is as follows: i) investigate offshore wind and wave energy potential, complementarity & synergy, and correlation between the two resources in southern China's coastal region using long-term data; ii) analyze the benefits of wind-wave joint exploitation considering specific offshore wind turbine (OWT) and wave energy converter (WEC); and iii) propose a new index to determine the suitability for co-developing wind-wave projects. The results show that the Beibu Gulf and Taiwan Strait experience the highest correlation between the two resources, in contrast to the Zhejiang coast that exhibits the lowest one. On the other hand, the east waters of Taiwan and Zhejiang coast have the highest synergy. Moreover, quantitative and qualitative analysis shows that the combined device generates less variable power output and zero production in the areas with low correlation and high synergy than the OWT/WEC operating alone. The suggested best sites for future joint exploitation are along the Zhejiang coast, with the potential of generating nearly 40 GWh/year per combined device of SWT-6.0-154 and 6 MW Wave Dargon.