Responses of hydroelectricity generation to streamflow drought under climate change

Hydropower is a key renewable energy source. It is widely developed worldwide to reduce carbon emissions and mitigate climate change. Hydroelectric generation (HG) is highly susceptible to streamflow and is negatively affected by streamflow droughts. However, there is a lack of studies on the impact of streamflow drought on HG in the coming future period under climate change. Therefore, to address the above challenge, an HG model is constructed to estimate future HG in China using simulated streamflow from four global hydrological models (GHMs) driven by four global climate models (GCMs) under two emission scenarios (i.e., RCP2.6 and RCP8.5). Results reveal that, compared with the baseline period of 1951-2005, more than 25% of the hydropower plants are expected to experience an HG reduction (with a 10-year return period) of greater than 20% of the baseline-mean annual HG in the future. More than 10% of installed capacity may suffer HG reductions of more than 30%. HG in the Yangtze River valley, which accounts for more than 22% of China's installed hydroelectric capacity, is expected to decline by more than 14% during 2031-2060. The HG reduction of several hydropower plants in northwestern and southern China will be greater than 60%. To combat the impact of streamflow droughts on regional energy security, it is desired that policymakers promote the development of a cross-regional energy integration network.