The impact of transportation infrastructure and industrial agglomeration on energy efficiency: Evidence from China’s industrial sectors

Transportation infrastructure plays an essential role in stimulating demand and booming economy in China. Meanwhile, evidence suggests that the development of transportation infrastructure and the resulting industrial agglomeration are highly associated with excessive energy consumption. Under the dual tasks of economic growth and environmental protection, we aim to investigate the mechanism by which transportation infrastructure and industrial agglomeration affect industrial energy efficiency in China. Based on panel data of China’s 30 provincial-level regions from 2000 to 2017, we apply the threshold panel model to verify the nonlinear relationship between transportation infrastructure and industrial energy efficiency. The mediation model is also constructed to estimate the mediating effect of industrial agglomeration in the association between transportation infrastructure and energy efficiency. The results show that there exists a nonlinear relationship between transportation infrastructure and industrial energy efficiency. Transportation infrastructure positively affects industrial energy efficiency only when a certain threshold is exceeded. Also, industrial agglomeration functions as a mediator in the relationship between transportation infrastructure and energy efficiency, indicating that transportation infrastructure not only directly affects energy efficiency, but also exerts an indirect effect through industrial agglomeration. These findings reveal the importance of developing transportation network, and seeking coordination between transportation infrastructure and industrial agglomeration.