Coal-fired peak regulation for integrating photovoltaic and wind power: Impact analysis and optimization of capacity tariff

The large-scale development and utilization of green electricity, particularly photovoltaic (PV) and wind power, is a key pathway for China's energy system to achieve low-carbon transition. However, the inherent intermittency and instability of PV and wind power pose significant challenges to the stable operation of the power system. Coal-fired utilization hours decreased from 5876 h in 2005 to 4476 h in 2023(−23.8%). This study designs a quasi-natural experiment based on China's policies for integrating PV and wind power into the grid. Using intensity-based DID methods at both the provincial coal-fired power macro level and the coal-fired power enterprise micro level, we examine the impact of PV and wind power integration on the utilization efficiency of coal-fired power equipment. The results indicate that the integration of PV and wind power significantly reduces the utilization levels of coal-fired power units. Mechanism analysis reveals that PV and wind power substantially substitute for coal-fired power while also exhibiting complementary effects. Heterogeneity analysis shows that the negative impact of PV and wind power integration on coal-fired power is stronger in provinces/regions with higher wind power potential relative to total PV and wind power potential, higher electricity supply rates, slower progress in the transformation and upgrading of coal-fired power, and lower levels of economic development. Further analysis indicates that large-scale coal-fired power enterprises, leveraging cost synergies, are more actively participating in the integration of PV and wind power. Finally, this study develops an optimization model for coal-fired power capacity tariffs based on the coefficient of variation method, enabling province- and region-level differentiation in the adjustment of current capacity tariffs. This study provides empirical evidence and reference solutions to alleviate green electricity integration pressures and accelerate the construction of a new energy system.