A recent study published in Engineering titled “Properly Positioning Coal Power in Decarbonizing the Global Power Systems” offers a nuanced perspective on the role of coal power in the global transition towards renewable energy. The research, led by Jinze Li from North China Electric Power University, explores the potential of coal power flexibility to support the integration of variable renewable energy (VRE) into power systems while addressing the challenges of decarbonization.

Coal-fired power plants have long been identified as a major source of carbon dioxide emissions, contributing significantly to global warming. However, the study highlights that coal power, through flexibility retrofitting, can enhance the integration of renewable energy into electricity systems by providing essential services such as rapid ramping, cycling, and reliable capacity backup. This approach is particularly relevant as the world moves towards a decarbonized power system in a just and orderly manner, as emphasized by the United Nations Climate Change Conference 28 (COP28).

The research underscores the importance of flexibility in coal power plants, which refers to their ability to accommodate significant fluctuations in output and respond promptly to changes in electricity demand. The study analyzes various metrics and costs associated with coal flexibility, finding that flexibility retrofitting can improve the regulatory capacity of power systems, reduce carbon emissions, and provide economic benefits for operators. This is achieved through equipment upgrades and optimization of operational strategies, transforming coal-fired power units from base load positions to flexible resources capable of providing rapid ramping, deep peak-shaving, and frequency response.

The study also examines the role of coal power flexibility across different phases of renewable energy development. In countries with a high penetration of VRE, such as Denmark and Germany, coal power flexibility is crucial for maintaining grid stability and providing ancillary services. In contrast, in countries with a lower share of VRE, such as Vietnam and Indonesia, coal power serves as a primary source of electricity while also undergoing flexibility upgrades to prepare for future renewable integration.

The research further discusses the economic implications of coal power flexibility. The costs associated with flexibility retrofitting include capital expenditures for technological upgrades and operational costs related to increased wear and tear on equipment. However, these costs are offset by benefits such as revenue from grid ancillary services, carbon trading, and subsidies for peak-shaving capacity. The study highlights that the economic viability of coal power flexibility depends on the policy environment, market mechanisms, and technological advancements in each country.

Moreover, the study emphasizes the importance of policy support in promoting coal power flexibility. Various countries have implemented different policies to incentivize flexibility retrofitting, ranging from direct financial support to carbon pricing mechanisms and renewable energy quotas. For example, China has launched multiple pilot projects and provided subsidies for peak-shaving units, while Germany has developed innovative strategies to utilize soon-to-be-retired coal-fired power plants as backup systems for grid safety redundancy.

The research concludes that coal power flexibility can play a positive role in decarbonization efforts, especially during the transition period when renewable energy cannot fully replace coal power. The findings suggest that with appropriate policy support and technological innovation, coal power can contribute to a more sustainable and stable energy future. As the world continues to pursue ambitious climate goals, the study provides valuable insights for policymakers and industry stakeholders on how to effectively integrate coal power flexibility into the broader energy transition strategy.

The paper “Properly Positioning Coal Power in Decarbonizing the Global Power Systems,” is authored by Jinze Li, Fang Fang, Yuanye Chen, Songyuan Yu, Jizhen Liu, Yanjun Du, Ming Du, Yi Zhang, Qinghua Wang, Yuguang Niu. Full text of the open access paper: https://doi.org/10.1016/j.eng.2025.06.019. For more information about Engineering, visit the website at https://www.sciencedirect.com/journal/engineering.