How digital finance and green finance can synergize to improve urban energy use efficiency? New evidence from China

Accelerating the greening and digital transformation of the energy industry to enhance energy efficiency is pivotal for constructing a new energy system. The high-quality development of the energy sector necessitates the support of emerging financial forces. This study utilizes panel data from 279 prefecture-level cities spanning from 2011 to 2021, employing mediation and moderation models to verify the synergistic impact of digital finance and green finance on energy efficiency. Findings indicate that the synergy between digital finance and green finance enhances energy efficiency. Mechanism analysis reveals that this synergy promotes energy efficiency through advancements in green and digital technology innovations. Climate policy uncertainty positively moderates the process by which digital finance and green finance synergistically improve energy efficiency, enhancing the intermediary effects of digital and green technologies. Environmental regulations similarly exert positive moderation on the joint impact of digital finance and green finance on energy efficiency, yet their effects vary heterogeneously, with market-based environmental regulatory tools demonstrating superior policy outcomes. Moreover, the impact of the synergy between digital finance and green finance on energy efficiency exhibits heterogeneity across geographic regions, development timelines, resource endowments, and policy trial effects.