Research on the Economics of Multi-Source Coupled Combined Heat and Power in Coal-Fired Power Units

Under China’s "dual-carbon" strategy, coal-fired power units face the twin challenges of energy conservation and flexible peak regulation. Addressing the economic complexity of multi-source coupled cogeneration systems characterized by "multiple users–multiple steam sources–pipe-main scheme," this paper takes a 2 × 660 MW ultra-supercritical plant as its case study. An integrated thermodynamic model encompassing turbine, boiler, and steam-supply systems was developed to establish a methodology for economic analysis of such multi-source coupled combined heat and power (CHP) unit. Through simulation, the generation coal consumption of each steam source supplying each user across the full-load range was quantified, revealing the economic characterization of intermediate-pressure regulation valve(IPRV)–assisted steam supply. A dimensionless steam-supply pressure coefficient was proposed, and the economic boundary for IPRV–assisted multi-source steam supply was derived. For both single-unit and duel-unit operation, safety constraints were integrated to formulate a "pressure-adaptive, dynamic-valve" strategy and a "dedicated high/low-pressure steam supply" strategy, thereby unlocking economic benefits under medium-low loads and high heat-to-power ratios while maintaining unit flexibility and reliable steam delivery.