International Transport Corridors and Urban Energy Efficiency—A Quasi-Natural Experiment Based on the Opening of the China-Europe Express Railway

Continually improving energy efficiency is a crucial path to promoting high-quality economic development and achieving carbon neutrality goals. This paper utilizes the opening of the China-Europe Express Railway as a qua-si-natural experiment and employs a multi-period difference-in-differences model with panel data from 281 Chinese cities from 2007 to 2019 to investigate the impact of the railway's opening on urban energy efficiency. The findings indicate that the launch of the China-Europe Express Railway significantly boosts urban energy efficiency. The mechanism analysis shows that the railway primarily enhances urban energy efficiency through technological innovation, industrial structure upgrading, and economic agglomeration. Heterogeneity analysis reveals that the positive effect of the railway's opening on energy ef-fi-ciency is more pronounced in central cities, key environmental protection cit-ies, and non-old industrial cities. The conclusions of this study offer im-portant practical insights for realizing the "dual carbon" goals and China's high-quality economic development.