Are government subsidies effective in improving innovation efficiency? Based on the research of China's wind power industry

China's wind power industry has rapidly developed and the level of technological innovation has been improved greatly with the government's funding support. However, few studies have considered whether government subsidies are effective in improving the innovation performance of Chinese wind power industry. To answer the above problem, this paper uses the sample data of listed wind power enterprises from 2012 to 2018 to evaluate the innovation efficiency of Chinese wind power industry. We employ a stochastic frontier model based on the translog production function, analyze the impact of government subsidies and other enterprise characteristics on innovation efficiency. Our results show that, first, the innovation efficiency of China's wind power industry is relatively low, but the overall trend is upward. Second, in the long term, there is a U-shaped relationship between government subsidies and innovation efficiency, reducing government subsidies can improve innovation efficiency before the turning point. Third, the effect of ownership concentration and financial leverage is not significant, but employees' high quality and high profitability play a significantly positive role in improving the innovation efficiency of China's wind power industry. The conclusions also provide a reference to policy making for the sustainable development of Chinese wind power industry.