The share of the fossil-fuel power systems in the European Union energy portfolio has recently increased, even with new environmental incentives aimed at the reduction of CO2 emissions from the power sector. Implementation of carbon capture technologies has been identified as a critical step toward reduction of CO2 emissions. As the power plants usually operate with changing loads to meet the electricity demand, it is important to evaluate the process performance under different operating loads. Therefore, this study provides a methodology for modeling of part-load operation of coal-fired power plants in a process simulator, such as Aspen Plus. The part-load power plant model is validated using data from the literature, and it was demonstrated that a maximum discrepancy of 5% was obtained for the live steam pressure prediction at 40% load, while the discrepancy for all other compared parameters at other loads did not exceed 3%. Furthermore, the part-load model is used to evaluate the performance of the retrofitted power plant with the CO2 capture plant at different loads, with monoethanolamine as a solvent, revealing that the net efficiency varied between 28.2%(HHV) and 21.1%(HHV). Moreover, the analysis showed that neglecting the off-design conditions due to steam extraction would result in overestimating the net thermal efficiency by up to 1.3%(HHV) points at 100% load operation and steam extracted at 11.9 bar.