A novel approach to optimize offshore wind farm siting in the Eastern China Sea

Long-term planning of offshore wind farms is essential for sustainable wind energy utilization. Currently, offshore wind farm siting in China is largely guided by policy priorities, often with insufficient integration of wind energy resource assessments and socio-ecological considerations. This may result in diminished project efficiency and elevated ecological and environmental costs. This study proposed a methodology that combined multisource heterogeneous data, enabling coupling of wind, ecological, and economic datasets. Using the Delphi method (Delphi) and Geographic Information System (GIS), scenarios were developed based on wind energy effects, ecological impacts, and economic costs. The results showed that ERA5 data was highly consistent with the regional wind energy performance. In the wind energy scenario, the high suitability sites were mainly located 50–75 km offshore in northern Fujian and southern Zhejiang, with an area of 142,114 km². In the ecological scenario, the medium suitability sites were located at least 110 km offshore, and the high suitability sites were at least 260 km offshore. Although the ecological disturbance decreases with increasing offshore distance, the economic cost increases. In the economic scenario, the high suitability sites were located within 90–150 km offshore and covered an area of 150,769 km². The total area of optimized high suitability sea area for wind farms was finally identified as 179,904 km² through the weighting of the scenario indicators, of which 6106.83 km² was located in the northern part of Fujian, 95 km offshore, and the rest of it was distributed in the sea area beyond 250 km offshore. In addition, current wind farms were mainly located in areas of low and medium suitability, emphasizing the potential for future wind power development in areas of high suitability. This novel approach provides a practical tool for optimizing offshore wind farm siting in China and offers a transferable framework applicable to other countries and regions with available multisource data, supporting more balanced and sustainable offshore wind development.