Assessment of offshore power potential in Zhoushan archipelago using a 45-year wind field product

The growing demand for sustainable offshore wind energy has heightened the need for accurate wind resource assessment and feasible turbine deployment. Conventional multi-factor assessments fall short of identifying wind energy hotspots in multiple islands environment. This study proposes a three-stage wind resource assessment framework aimed to capture inter-island variations of wind resources across Zhoushan Archipelago. A long-term wind energy assessment at 100 m height is first conducted by using the optimal product through inter-comparison of seven mainstream global wind datasets against observations from ten evenly distributed sites. An Islands-Oriented Multi-Criterion assessment method, integrating energy, risk-stability, and environmental-cost factors, is then proposed to classify wind resources. Unconstrained offshore wind turbine zones are identified in the end through GIS-based spatial planning. Zhoushan Archipelago demonstrates substantial wind energy potential, with most areas exhibiting annual wind power density of about 420–550 W/m2 but notable spatiotemporal variability, particularly low stability in central regions. The maximum energy potential concentrates in southeastern open seas (500–550 W/m2), with values gradually decreasing westward and exhibiting moderate levels near Hangzhou Bay (360–440 W/m2). The optimal turbine deployment zones are identified around Yushan Island, followed by Hangzhou Bay and east of Shanghai. Unconstrained suitable areas yield maximum technical potential of 29.48 TWh/yr. These findings provide actionable insights for wind energy planning in Zhoushan and other multi-island regions globally, emphasizing spatial prioritization and resource optimization.