Electric power, the largest coal consumption sector in China, emits a large amount of carbon dioxide and air pollutants. The health risks incurred by coal-fired power pollution emissions cannot be ignored, and carbon dioxide emissions are always at a high level although a series of policies such as the elimination of backward production capacity, ultra-low emission transition and energy saving and carbon reduction transition have significantly reduced the air pollutant emissions of the coal-fired power industry. To realize the goals of carbon neutrality and clean air in China, it is imperative to promote the transition of the coal-fired power industry and promote the coordinated governance of pollution reduction and carbon reduction in the industry. Researches have designed the pathway of coal power phaseout with the best health co-benefit and the least stranded assets from the unit scale. In reality, however, coal power phaseout may be affected by many factors, resulting in the environmental, climate and economic benefits and costs deviating from the optimal expectations.

To address the above problems, Tong Dan’s Research Group of the Department of Earth System Science (DESS), Tsinghua University have established an uncertainty analysis framework for Chinese coal power phaseout strategy under multi-objectives, innovated massive scenario optimization technology, quantified the cost-effectiveness of several coal-fired power transition pathways in China, analyzed the cost-effectiveness uncertainty brought by pathway disturbance, and revealed that the uncertainty of low-carbon coal-fired power transition pathways in China may lead to differences in climate, environment, health benefits and economic costs, as well as deviations from the policy’s expected objectives. The research results were published in a paper titled “Cost-effectiveness uncertainty may bias the decision of coal power transitions in China” in Nature Communications on March 13.

To quantify the impact of uncertainty in coal power transition in China, the Research Group put forward an uncertainty analysis framework of coal power transition strategy in China for multi-objective decision-making by coupling the comprehensive evaluation model, the atmospheric chemical adjoint model, exposure-response equation and the cost-effectiveness evaluation method of coal power transition. Based on the model framework, starting from the heterogenous characteristics of unit-level coal-fired power, such as the risk of stranding assets, carbon emission reduction benefit and health impact, several targeted transition pathways have been designed, and the transition costs, climate, environment and health benefits and their uncertainties are quantitatively characterized. Through multi-criteria decision analysis, how the low-carbon transition benefits of coal-fired power in China deviate from expectations under the impact of uncertainties has been revealed.

It has been found in the research that the distribution of carbon emissions and health risks of coal-fired power units in service presents significant heterogeneity: nearly a quarter of carbon emissions are caused by coal-fired power units with an installed capacity of 10%, while coal-fired power units with an installed capacity of 2% cause more than 25% health risks in the coal-fired power industry. Implementing targeted decommissioning strategy is expected to achieve considerable benefits in carbon emission reduction and people’s health protection.

Based on the heterogeneous characteristics of coal-fired power units, the study further analyzes the disparities of decommissioning pathways of coal-fired power units from the multi-objective perspective of assets stranding, carbon emission reduction and health benefits. Through the disturbance simulation analysis of ten thousand groups of decommissioning pathways, it has been found that the uncertainty may delay the time node when the decommissioning policy obtains positive effects for the first time, and the current decommissioning strategy may delay the time of obtaining positive effects for six years (Figure 1). There is a certain degree of risk in the implementation of any decommissioning policy, and not all strategies can guarantee 100% cumulative net benefits, especially with regard to the targeted decommissioning strategy with the primary goal of carbon emission reduction and asset stranding avoidance and the continuation of the current decommissioning strategy, which are both likely to cause cumulative negative effects. Under the disturbance of the uncertainty of policy implementation, even if a coal power phaseout strategy is designed strictly according to the policy objectives, it is still possible to miss the opportunity to implement the most suitable decommissioning policy (Figure 2). The study has demonstrated that in coal power phaseout, the disturbance of policy implementation should be minimized, and the risk of negative effects should be reduced, and meanwhile, the best strategy should be chosen to guide the orderly low-carbon transition of coal-fired power units in China according to the targeted policy objectives.

Figure 1 Trends and possible ranges of CO₂ emissions, deaths, and benefits for each strategy.

Figure 2 Preference analysis for coal power phaseout strategy design

The study has revealed the uncertainty of China’s coal power low-carbon transition policy and the impact of the spatiotemporal randomness of newly-built production capacity on decision-making and benefits, demonstrating that limiting policy disturbance and adopting coal power transition strategy based on targeted policy objectives are of great significance for coal power transition to improve quality and efficiency. The study also puts forward policy suggestions for the feasible route to achieve the synergetic goal of carbon neutrality and clean air. That is, the low-carbon transition of energy structure does not necessarily bring positive net benefits, and the top-level design should be strengthened when designing and implementing relevant energy policies, always guided by the overall strategic goals, so as to reduce the uncertainty risk of energy policies and promote the smooth low-carbon transition of the power systems.

Doctoral student Yan Xizhe of the DESS, Tsinghua University is the first author of the paper, and Assistant Professor Tong Dan of the DESS, Tsinghua University and Researcher Lei Yu of the Chinese Academy of Environmental Planning of the Ministry of Ecology and Environment are the corresponding authors. Co-authors include Professor Zhang Qiang of the DESS, Tsinghua University, He Kebin, Professor at the School of Environment, Tsinghua University, and Academician at the Institute for Carbon Neutrality, Tsinghua University, Professor Chen Shaoqing of Sun Yat-sen University, Associate Researcher Chen Yixuan and Assistant Researcher Chen Chuchu of the Chinese Academy of Environmental Planning of the Ministry of Ecology and Environment, Postdoctoral Fellow Liu Yang and graduate Shi Qinren (currently Postdoctoral Fellow at Le Laboratoire des Sciences du Climat et de l’Environnement, LSCE) of the School of Environment, Tsinghua University, graduate Chen Jing (currently Postdoctoral Fellow at the University of California, Irvine), and Doctoral Students Xu Ruoyi, Tan Xinying and Zheng Dongsheng of the DESS, Tsinghua University. This study is supported by the National Natural Science Foundation of China, the Energy Foundation, the New Cornerstone Science Foundation and Tsinghua University Initiative Scientific Research Program.

Full-text link: https://www.nature.com/articles/s41467-024-46549-5

Written by Yan Xizhe and Tong Dan

Edited by Wang Jiayin

Reviewed by Zhang Qiang