Inhibit first and then promote? The relationship between digital economy and urban low-carbon energy security

Developing digital economy (DE) holds paramount significance in improving low-carbon energy security (LCES). However, the lack of analyzing the relationship and influence channels between DE and LCES from micro level, making it difficult for local governments to make effective development plans. This study constructs the comprehensive indexes of DE and LCES across 278 Chinese cities from 2011 to 2021, utilizes the mediating effect model and moderated mediation effect model to examine the potential influence channels and moderating mechanism. The results show (1) DE has U-shaped influence on LCES, which exhibits varied effects due to differences in geographical regions and resource endowments among cities; (2) Green technology innovation, industrial structure upgrading and green finance development play the partial mediating effects between DE and LCES, however, the positive mediating effects will only appear when DE reaches a certain extent; (3) Environmental regulation (ER) moderates the first half of these mediating effects, strengthens the energy-saving effect of DE, which can accelerate the arrival of U-shaped curve's turning point. These results reveal the relationship between DE and LCES. Governments should formulate reasonable policy combinations tailored to local conditions, thereby accelerating sustainable development.