Projected impacts of climate change on hydropower potential in China

摘要

Hydropower is an important renewable energy source in China, but it is sensitive to climate change, because the changing climate may alter hydrological conditions (e.g., river flow and reservoir storage). Future changes and associated uncertainties in China's gross hydropower potential (GHP) and developed hydropower potential (DHP) are projected using simulations from eight global hydrological models (GHMs), including a large-scale reservoir regulation model, forced by five general circulation models (GCMs) with climate data under two representative concentration pathways (RCP2.6 and RCP8.5). Results show that the estimation of the present GHP of China is comparable to other studies; overall, the annual GHP is projected to change by -1.7 to 2% in the near future (2020-2050) and increase by 3 to 6% in the late 21st century (2070-2099). The annual DHP is projected to change by -2.2 to -5.4% (0.7-1.7% of the total installed hydropower capacity (IHC)) and 1.3 to -4% (0.4-1.3% of total IHC) for 2020-2050 and 2070-2099, respectively. Regional variations emerge: GHP will increase in northern China but decrease in southern China - mostly in south central China and eastern China - where numerous reservoirs and large IHCs currently are located. The area with the highest GHP in southwest China will have more GHP, while DHP will reduce in the regions with high IHC (e.g., Sichuan and Hubei) in the future. The largest decrease in DHP (in %) will occur in autumn or winter, when streamflow is relatively low and water use is competitive. Large ranges in hydropower estimates across GHMs and GCMs highlight the necessity of using multimodel assessments under climate change conditions. This study prompts the consideration of climate change in planning for hydropower development and operations in China, to be further combined with a socioeconomic analysis for strategic expansion.