Study on Dynamic Carbon Emission Characteristics of Coal-fired Units Based on Material Balance and Online Monitoring Methods

Under the background of low-carbon conversion of global energy structure, coal-fired units, as the main force of power system peaking, the accurate accounting of carbon emission and the study of dynamic characteristics are crucial for realizing the "dual-carbon goal". In this paper, five coal-fired units of different capacities in a power plant are taken as objects, and the differences in accounting between the material balance method and the online monitoring method are compared with the actual operation data, and the carbon emission response laws under steady state and dynamic loads are systematically analyzed. The study shows that the online monitoring method is higher than the material balance method by 6.97% on average because it covers the carbon emission of the whole process. Meanwhile, the large-capacity unit (1000 MW) has lower carbon emission intensity under steady state load than the 630 MW unit, and shows stronger stability in dynamic load fluctuation. In addition, there is a significant capacity dependence in the effect of load change rate on the dynamic response of carbon emission, and large-capacity units can suppress more pronounced transient fluctuations. This study provides an important basis for the optimization of low-carbon peaking and carbon verification methods for thermal power units.