Evaluating wind and solar complementarity in China: Considering climate change and source-load matching dynamics

Changes in wind and solar energy due to climate change may reduce their complementarity, thus affecting the stable power supply of the power system. This paper investigates the wind and solar complementarity in China under climate change from the perspective of source-load matching. First, the ability of the PRECIS model to simulate the wind and solar complementarity characteristics at different time scales (hourly, daily, and monthly scales) over China is verified. At the hourly scale, the complementarity shows an increasing trend from east to west, with Qinghai, Yunnan and Xinjiang exhibiting the most pronounced complementarity. The southeastern region exhibits smaller net load peak-to-valley differences and volatility, signifying a diminished requirement for system flexibility in this area, while northern and northwestern China exhibit a higher demand for system flexibility. Then, the changes of wind and solar energy complementarity and net load fluctuation are predicted in the 2030s and 2060s under the SSP2-4.5 and SSP5-8.5 scenarios. Overall, climate change is anticipated to have a negative impact on the future complementarity of wind and solar energy. In the 2060s, on an hourly scale, the complementary characteristic (τPr−L) shows a downward trend in most regions, particularly in eastern and central China, where it decreased by about 0.05 and 0.04. Furthermore, there is an escalation in the peak-valley difference and fluctuation of net load in most areas of China, particularly under the SSP5-8.5 scenario. The peak-valley difference of net load in the central and southwest regions projects a marked increase of 22.4 % and 18.7 % in the 2060s, suggesting that climate change is anticipated to augment the demand for power system flexibility, necessitating increased investments in flexible and adjustable resources such as energy storage.