Peak shaving and heat supply flexibility of thermal power plants

Abstract

• A model showing the plant-level operation domain is developed. • A scheduling scheme to improve operational flexibility is proposed. • The adjusting ranges of loads are obtained by particle swarm optimization. • The proposed scheme reduces CO 2 emissions while meeting heating demand. The operational flexibility of thermal power plants is important to consume renewable energy generation, especially in the regions where combined heat and power (CHP) units account for a high proportion. Focusing on the relationship between peak-shaving capacity of CHP units and the consumption of renewable energy generation, the problem about operational flexibility of CHP plants is analyzed in this paper. From the perspective of entire CHP plants rather than the renovation of one CHP unit, the problem regarding the operation scheduling without cost or risk is addressed. A plant-level operation domain model is established, which can improve the operational flexibility of CHP plants. The heat and power adjustable ranges of CHP plants were obtained by particle swarm optimization. Also the CHP plant located in northern China was taken as an example. The power load downward adjustment range of four periods in the heating season are 9.21%, 20.44%, 14.09% and 5.31% respectively, compared with the entire plant actual power under the same heat load. Moreover, the operational flexibility of CHP plants can be enlarged by decreasing the pressure of heating extraction. Compared with the entire plant actual operating conditions, the consumption of renewable energy generation could be increased by 268.56 million kWh approximately and about 0.22 million tons CO 2 emissions can be reduced per heating season if the reference plant operates with minimum power load constantly.