Integrating solar electricity into a fossil fueled system

The power sector is a major contributor to carbon emissions in China, accounting for nearly half of all emissions, and therefore emission reductions from this sector will be critical, if China is to meet its 2060 targets. Deploying renewable energy sources is the most promising approach to decarbonizing the power sector. However, the intermittency and non-dispatchable nature of wind and solar power pose significant challenges to grid stability, particularly when these sources reach high penetration rates. During China's ongoing energy transition, coalfired power units will be used to meet peak loads when solar and wind generation is not available. The economic and environmental implications of such a scenario are unclear. In light of this uncertainty, this study applies a unit commitment model to investigate the economic and environmental performance of load shaving strategies across different scenarios. Results show that, in the absence of energy storage systems, a solar penetration rate of 40 % will create an economic bottleneck, and high solar penetration would even increase the total carbon emissions of the whole power system. Moreover, the power system would choose to cycle the large thermal units first to accommodate the solar power, and start-stop strategy is subordinate.