Does the construction of comprehensive demonstration cities for energy conservation and emission reduction fiscal policy promote the dual structural transformation of energy and industry?

The energy conservation and emission reduction fiscal policy is a major institutional innovation in China's green finance sector and is crucial for achieving the "dual carbon" goals. This paper takes the pilot comprehensive demonstration cities for this policy as the exogenous policy impact, and analyzes its effects on energy and industrial structure transformation using a difference-in-differences model and a dual machine learning model. The results indicate that establishing comprehensive demonstration cities significantly enhances the optimization of energy structure and the upgrading of industrial structure in the region. These conclusions remain robust after a series of tests, including parallel trend and heterogeneous treatment effects. Mechanism analysis shows that the policy pilot can improve energy and industrial structures by promoting energy- and environment-oriented technologies and capacity utilization. Heterogeneity analysis reveals that the implementation effect of the pilot policy is more prominent in core large cities, non-industrial base cities, highly market-oriented cities, and cities with low financial pressure. Further research demonstrates that constructing demonstration cities offers obvious advantages in promoting the realization of six tasks initially set by the policy, including industrial decarbonization, clean transportation, green building, service intensification, reduction of major pollutants, and large-scale utilization of renewable energy. The findings of the study provide valuable insights for designing and implementing more comprehensive green fiscal policies in China in the future.