Industrial characteristics of renewable energy and spatial aggregation correlations in Beijing-Tianjin-Hebei

Beijing-Tianjin-Hebei is a key development zone in China, and the renewable energy industry is particularly concerned. This paper aims to combine spatial information with renewable energy industry to reveal the spatial-temporal evolution characteristics of industry and its driving factors. It is found that the industries in Beijing, Tianjin and Hebei show an obvious agglomeration pattern, with the renewable energy industry in the Beijing-Tianjin-Hebei region showing Moran's I = 0.385579 during 2005-2010, Moran's I = 0.319463 during 2010-2015, and Moran's I = 0.329409 during 2015-2020. The global spatial autocorrelation analysis shows that the agglomeration level of the renewable energy industry in the Beijing-Tianjin-Hebei region has not increased, but the local spatial autocorrelation shows that the areas with higher transportation and business levels tend to be significantly agglomerated in space. Through the Moran index, it is found that the industry in Beijing-Tianjin-Hebei presents an obvious agglomeration pattern, and through the hotspot analysis, the industrial agglomeration is found mainly occurs in Beijing, Tianjin, Shijiazhuang and Zhangjiakou, which can be explained by the factor agglomeration effect brought by urbanization. However, we further calculated the location quotient, Herfindahl coefficient and Gini coefficient, and found significant regional differences in Beijing-Tianjin-Hebei region. For example, the unipolar agglomeration effect was weakening. Further three-phase space ellipse more vividly reveals the Beijing-Tianjin-Hebei region of renewable energy industry in the past 20 years continued to form the benign industrial expansion. Starting from the capital Beijing, the industry moved southwest, driving the development of renewable energy industry in Hebei and Tianjin, and promoting the coordinated development of the Beijing-Tianjin-Hebei economic circle.