Research progress on energy-saving methods for coal-fired power systems in the new power system

<sec><p indent="0mm">“Energy Conservation Priority” is a long-term strategy adhered to in China’s economic and social development. The coal-fired power system, as the anchor for ensuring China’s energy and electricity security, has consistently focused its technological evolution on enhancing energy efficiency, emission control, and cost-effectiveness optimization. Under the “dual carbon” goals, the coal-fired power system is transitioning from the primary power source to a regulating power source, with a dramatic increase in peak-shaving and frequency-modulation tasks. In this new context, achieving deep energy conservation in coal-fired power systems during peak-shaving and frequency-regulation processes has become a major national strategic need to support the construction of a new power system. </sec><sec> This manuscript systematically summarizes the research progress in energy conservation for coal-fired power systems from three aspects: quantitative analysis methods for thermal economy, energy-saving methods for steady-state operating conditions, and energy-saving methods for transient processes under variable loads. </sec><sec> The long-term focus of quantitative analysis methods for system thermal economy has been on design conditions, primarily including the conventional heat balance method, cycle function method, equivalent heat drop method, and specific consumption analysis method. Based on thermodynamic principles, these methods determine the impact mechanisms of parameter deviations on energy consumption and extend these methods to variable operating conditions and multiple-type power systems. In recent years, thermal economy quantitative analysis methods have expanded from steady-states to transient processes, adopting additional energy consumption evaluation and data-driven analysis to characterize time-varying characteristics and quantify energy-saving potential, evolving from mechanism analysis to a hybrid mechanism-data analysis model. </sec><sec> Energy-saving methods for steady-state operating conditions include steam initial parameter improvement, exhaust terminal parameter optimization, regenerative system design optimization, reheat parameter selection, and turbine-boiler coupling process reconfiguration. Under deep peak-shaving conditions, system energy consumption surges and equipment safety risks intensify. Methods such as refined combustion adjustment, flow path modification, and variable frequency speed control are employed to achieve synergistic improvement in equipment safety and energy efficiency, while energy-saving methods for deep peak-shaving conditions still require further refinement. </sec><sec> The transient process under variable loads involves different time-scale processes, including primary frequency regulation (seconds), secondary frequency regulation (minutes), and tertiary frequency regulation (hours). Key energy-saving methods include optimization of main unit control strategies based on thermodynamic analysis for active regulation of heat storage, big data-driven optimization of main unit control parameters, optimization of auxiliary equipment transient control strategies, and improvement of electricity market trading mechanisms based on price incentive mechanisms. </sec><sec> To establish a clean, low-carbon, secure, and efficient new power system, future research urgently needs to focus on three aspects: energy-saving methods for coal-fired power under ultra-low loads, breakthroughs in thermal cycle optimization methods for higher parameter levels, and the construction of intelligent precision control methods for coal-fired power generation. </sec>