Cost-effectiveness of removing the last 10%–20% emissions of China’s power sector

Power system decarbonization is central to achieving global net-zero emissions goals. While existing studies highlight the technological complexities, flexibility challenges, and cost implications of achieving carbon neutrality, mitigating the last 10%–20% of power system emissions in China has not been sufficiently addressed. Here, we estimate the impacts of eliminating the last 10%–20% of CO₂ emissions on new capacity, the transmission network, system costs, and climate and public health benefits. We find that although system costs slightly increase (less than 1%) under deep decarbonization in China, climate and health benefits are substantial. We further investigate the role of three important emission mitigation technologies (nuclear, offshore wind, and carbon capture and storage) in power system deep decarbonization. Our analysis shows that none of these technologies would significantly affect future system costs but they influence both the quantity and location of renewable energy installations and the expansion of China’s transmission network. With China’s power system, the world’s largest, we demonstrate the cost-effectiveness of achieving a net-zero electricity sector and offer insights on implications for renewable development and transmission expansion when prioritizing decarbonization technologies.