Renewable energy droughts shape the air pollution patterns through power system response

Accelerating the energy transition toward a new electricity system dominated by renewable energy, with coal power serving as a flexible backup, is a critical strategy to synergize pollution control and carbon reduction. This study couples a power system model with WRF-CMAQ to reveal the power system's response to renewable energy droughts and assess associated environmental impacts. Our findings reveal that while large-scale development of renewable energy will contribute to the reduction of anthropogenic emissions and overall air quality improvement across China, it also introduces regional increasing pollution. The annual average PM_2.5 concentrations exhibit significant increases in the Border Area of Jiangsu, Anhui, Shandong, and the Twain-Hu Basin, accompanied by a rise in the frequency of mildly polluted days in the Twain-Hu Basin and the Sichuan Basin. Moreover, the Twain-Hu Basin experiences a nearly tenfold surge in short-term severe air pollution episodes compared to the baseline scenario. These regional pollution spikes are linked to renewable energy droughts triggered by extreme low-wind, extreme low-radiation, and compound low-wind-low-solar events. Our research underscores that while advancing the integration of wind and solar, it is essential to conduct regional environmental risk assessments across multiple time scales and enhance extreme weather early warning and emergency response mechanisms.