China will strictly control coal‑powered electricity projects and vigorously develop renewable energy power. According to China’s power development plan, by 2030 the total installed capacity of wind and solar power will exceed 1.2 billion kilowatts, making them the country’s primary power source. However, renewable energy also has a significant “uncontrollable” drawback: its installed generating capacity is severely constrained by natural meteorological conditions such as daylight hours, seasonal variations, cloudy or sunny weather, and wind speed. According to reports, in 2019—when non‑fossil energy accounted for only 32.6% of the nation’s total power generation—wind and photovoltaic power generally faced challenges in grid connection, power consumption, and system dispatch. Therefore, over the coming decades, as China transitions from a coal‑dominated power system to a new type of power system centered on new energy sources, coal‑fired power plants cannot be phased out of power generation; they will continue to serve as the “ballast” ensuring stable power production, supply, and flexible regulation. Consequently, how to make coal‑powered generation more efficient, cleaner, lower‑carbon, and more flexible has become an urgent task that the power sector must now study and address.

　　Against this backdrop, in May of this year, China Southern Power Grid Company released the “White Paper on the Action Plan for Building a New Power System (2021–2030)” in Guangzhou, outlining its plan to basically complete the construction of a new power system by 2030, while ensuring efficient integration of new energy sources and reliable power supply in the process of achieving peak carbon and carbon neutrality goals.

　　Thermal power is the most economical and reliable peak-shaving power source for the Southern Power Grid.

　　As the installed capacity of volatile renewable energy sources—primarily wind and solar power—continues to grow, the ability of power systems to operate with flexibility has become increasingly important. Power system flexibility is primarily used to assess a power system’s capacity, over relevant time scales, to manage supply–demand volatility and uncertainty in a reliable and cost‑effective manner. This means that the flexible operation capability of power systems will be at the core of future power system transformation. Given China’s unique energy resource endowment, coal‑fired generating units must continue to play a vital role as a stabilizing force within the domestic power grid. Even by 2060, the grid may still rely on coal power as a regulating power source to meet its safety requirements. While electrochemical energy storage currently suffers from low energy density and high investment costs, lithium’s position in the periodic table makes it highly unlikely that battery storage technology will achieve breakthroughs in the short term. Similarly, nuclear fusion-based energy storage remains challenging to realize in the near term due to its inherent technical difficulties. Therefore, until breakthroughs are made in battery storage or controlled nuclear fusion, thermal power generation will remain essential as a long‑term stabilizing force. For the Southern Power Grid, this means vigorously pursuing flexibility upgrades for coal‑fired power plants and providing more high‑quality, flexible peak‑shaving power sources. When large volumes of new energy are integrated into the grid, these resources can effectively address the intermittency, high volatility, and forecasting challenges associated with new energy, while ensuring reliable power output and meeting stringent reliability standards. Thermal power remains the most suitable peak‑shaving power source for the Southern Power Grid, safeguarding its safe, stable, and efficient operation.

　　Flexibility Retrofit of Thermal Power Plants and Coordination Strategies for Southern Power Grid Operations

　　There are significant differences in the design and manufacturing of coal-fired power generating units across China. The three major core components—boilers, steam turbines, and generators—each have different design and manufacturing requirements set by their original manufacturers. The technical parameters for safe operation vary among these three major components, as do their respective load regulation ranges. When the power grid engages in peak-shaving operations, each unit has its own optimal depth of peak-shaving. Deep peak-shaving in coal-fired units can have a substantial impact on the economic performance of power generation enterprises, often leading to an increase in coal consumption per unit of electricity generated. Therefore, a thorough techno‑economic comparative analysis is necessary to determine the lower limits for deep peak-shaving across different unit types, selecting a reasonable and economically viable peak-shaving threshold—not the lower the boiler load, the better. When carrying out deep peak-shaving upgrades, it is essential to tailor solutions to local conditions, developing specific technical approaches based on the unique characteristics of each boiler and the properties of the available coal, rather than adopting a one-size-fits-all approach or rigidly pursuing a uniform technical roadmap. Before implementing deep peak-shaving technology upgrades for boilers, a comprehensive safety assessment must be conducted, with particular attention paid to unforeseen safety risks; robust risk mitigation measures must be put in place. Monitoring points should be increased to ensure the safe and stable operation of units following flexibility upgrades—and reckless upgrades must be avoided at all costs. Consequently, flexibility upgrades for thermal power plants must be grounded in the actual conditions of coal‑fired power plants, with thorough communication and collaboration with grid operators. Based on factors such as grid load patterns and local renewable energy capacity, the specific extent of deep peak-shaving should be carefully selected.

　　Reflections on Power Grid Security under a New Type of Power System Dominated by New Energy Sources

　　With the large-scale integration of new energy sources—especially as coal-fired power plants are set to undertake extensive deep peak-shaving operations in the future—grid operators and power generation companies must, from a safety perspective, strengthen their bottom-line thinking and red-line awareness. They need to establish and improve comprehensive safeguard mechanisms that cover pre‑renovation assessment and optimization with robust risk prevention, in‑process oversight during renovation, and post‑renovation safe operation and technical supervision. Deep peak-shaving for thermal power units presents numerous hidden risks, requiring extensive and painstaking exploration tailored to different types of equipment. Deep peak-shaving for coal-fired units calls for top‑level design and the formulation of relevant standards to ensure the healthy development of the entire power industry and provide strong, reliable support for the nation’s socioeconomic life. Faced with complex deep‑peak‑shaving operating conditions, grid operators and power generation companies must vigorously leverage artificial intelligence—particularly deep learning technologies—in areas such as soft sensing, fault diagnosis, and automatic control, further showcasing the application of these new technologies to guarantee the safe operation of the power grid. Special emphasis should be placed on preventing and mitigating the safety risks associated with rapid start‑up and shut‑down, swift ramp‑up, rapid load changes, and prolonged low‑load operation following renovation, while rigorously guarding against the occurrence of major safety incidents involving the grid.

　　Reflections and Prospects

　　Under the “Dual Carbon” strategic goals, the development direction of China’s power industry is to “build a new type of power system with new energy as the mainstay.” Coal-fired power plants are the most cost‑effective peaking power sources and play a crucial role in ensuring the safe and stable operation of the grid. Grid enterprises and power generation companies must engage in in-depth communication and close collaboration, while strengthening their capacity for scientific and technological self-reliance and self‑improvement. We are confident that in the near future, through breakthroughs in key technologies, we will surely achieve coordinated, high‑quality development between coal‑powered enterprises and grid enterprises under a new power system centered on new energy, providing robust and reliable support for the nation’s social and economic life, and contributing the wisdom and strength of power technology professionals to the realization of the Dual Carbon goals.

　　(Author Li Debo is a Senior Engineer at China Southern Power Grid Technology Co., Ltd.)