In order to study the carbon emission characteristics of coal-fired units under different operating conditions

the carbon accounting method based on energy balance and the conservation of materials is adopted to realize the minute level continuous monitoring of carbon emission intensity of coal-fired units. Then

the carbon emission intensity of 4×600 MW and a 1 000 MW unit is monitored and analyzed. The results show that

the carbon emission characteristics of each unit have significant differences. The carbon emission intensity of some units increases sharply when the load is reduced to less than 50%. But for other units

the carbon emission intensity changes gently under the condition of deep peak regulation. The carbon emission intensity of some thermal power units is sensitive to load fluctuation

in which a greater load fluctuation leads to a higher carbon emission intensity.The carbon emission intensity of lean coal units is higher than that of bituminous coal units of the same grade. These research results can provide references for power grid low-carbon scheduling

and support the power grid to consume new energy and reduce the overall carbon emission of coal-fired units through adjusting the generator set combination.