Economic Optimization of Combined Heat and Power Operation Based on a Bypass Thermal Storage Method for District Heating Networks

Abstract

High renewable energy penetration and growing heating demand in northern China pose challenges to the operational flexibility and economic performance of combined heat and power (CHP) units. District heating networks can address these challenges through their inherent thermal storage capacity, but the conventional supply-water-temperature-rise method does not fully exploit the return network’s storage potential. To address this issue, a bilevel model based on bypass-assisted thermal storage is developed to optimize bypass-device configuration and improve CHP economic performance. The results show that installing bypass devices at selected stations can exploit the return network’s storage potential, expand CHP flexibility, and improve unit economics during peak- and valley-price periods. In the long-distance network case, peak-shaving compensation under the conventional method failed to offset the reduction in unit operating profit. The bypass method produced a life-cycle net present value of 10.86 million yuan. In the primary-network case, the life-cycle net present value was 44.70% higher than that achieved by the conventional method. These findings support the exploitation of district heating network storage potential and flexible CHP operation.