Quantifying the Cross-Regional Spillover Effects of Offshore Wind Power on National Carbon Footprint: Insights from China’s Two Largest Installed Capacity Provinces

As a clean and renewable energy source, wind energy offers lower development and utilization costs than solar energy, making it the most promising renewable option. However, the carbon footprint of offshore wind power and its external impacts on cross-regional carbon emissions have not been investigated sufficiently. Using the provinces of Guangdong and Jiangsu as case studies, this study employs socioeconomic and environmental statistical data. It applies the environmentally extended multi-regional input–output (EE-MRIO) method to quantify cross-regional environmental spillover effects associated with offshore wind power development. The findings show that China’s power structure has been continuously optimized, with offshore winds achieving leapfrog growth since 2010. Through a “local consumption” model, offshore wind power in Guangdong and Jiangsu has effectively replaced coal-fired generation, substantially reducing carbon emissions locally and in neighboring areas. Jiangsu has reduced CO2 emissions by 16.72 million tons annually, and Guangdong by about 7.23 million tons annually. Furthermore, offshore wind development drives the green transformation of upstream industries (e.g., steel, non-ferrous metals, and chemicals). It extends carbon-reduction benefits to resource-rich regions such as the Northwest and North China. As major manufacturing hubs, both provinces lowered the embodied carbon intensity of their export products by using clean electricity, thereby indirectly reducing the national carbon footprint through cross-regional trade. This study offers scientific insights to help policymakers optimize offshore wind layouts, facilitate coordinated regional emission reductions, and advance sustainable energy transitions.