Quantifying the impact of extreme weather on China’s hydropower–wind–solar renewable energy system

Carbon reduction goals have driven China to become the world’s largest renewable energy system (RES) that is dominated by hydropower, wind power and solar power. However, the meteorological sensitivity of wind and solar power greatly affects the reliability and generating capability of the RES, particularly in extreme weather events. Quantifying the electricity supply and flexibility of hydropower is crucial for compensating extreme wind and solar power generation. Here we investigate the influence of extreme weather combinations and future climate on the generating capability of the national RES and quantify the flexibility demand and hydropower supply in typical extreme weathers. Our analysis reveals that the annual utilization hours of the hydropower–wind–solar system are projected to decline by nearly 12% from the current stage to 2060 under conditions of extreme drought, low wind and weak solar radiation. When encountered with extremely strong solar radiation and wind, the probability of flexibility shortages in hydropower is estimated to rise to 47% by 2030 and further increase to 60% by 2060. Nearly half of the provinces will require tens of millions of kilowatts of energy storage by 2030 to supplement the flexibility supply gap of hydropower, and by 2060, both the number of provinces that require such a large-scale energy storage and the storage capacity needs might double. Our findings provide early warnings in extreme electricity supply and underscore the growing necessity for building dispatchable power plants and exploring the flexibility of existing hydropower systems. Renewable energy sources have become the dominant power sources in China's electricity system. By investigating the influence of extreme weather combinations on the country's hydropower–wind–solar system, the authors project that there will be a decline of nearly 12% by 2060 in annual utilization hours under conditions of extreme drought, low wind and weak solar radiation.