Uncertainties exist in load dispatch with unit commitment and affect the unit load dispatch. By comprehensively considering the load forecast uncertainty

unit coal consumption rate uncertainty and CO_2 emission coefficient uncertainty

this paper establishes optimal load distribution model for the thermal power plant taking the minimum primary energy consumption costs and the least emission of CO_2 as objects. On this basis

the coupled factor analysis and variance decomposition method is employed to disclose the influence of multiple uncertainties on primary energy consumption and CO_2 emission. Case analysis results show that

load forecast uncertainty exhibits the most influence on aforementioned two optimization objectives

which accounts for 51.13% and 62.70%

respectively. The coal consumption rate uncertainty and CO_2 emission coefficient uncertainty lie second

which accounts for 47.58% and 34.95%

respectively. The proposed framework in this study is a positive explore for load dispatch under uncertainty.