Carbon capture for fossil fuel power generation attracts an increasing attention in order to address the significant challenge of global climate change. This study aims to explore the optimal operation under different market conditions for an assumed existing natural gas combined cycle (NGCC) power plant integrated with MEA-based post-combustion carbon capture (PCC) process. The steady state process models for NGCC power plant, PCC process and CO2 compression train were developed in Aspen Plus® to give accurate prediction of process performance. Levelised cost of electricity (LCOE) is formulated as the objective function in optimization studies. Economic evaluation was carried out for the base case of the integrated system including CO2 transport and storage (T&S). The optimal operations were investigated for the carbon capture level under different carbon price, fuel price and CO2 T&S price. The study shows that carbon price needs to be over €100/ton CO2 to justify the total cost of carbon capture from the NGCC power plant and needs to be €120/ton CO2 to drive carbon capture level at 90%. Higher fuel price and CO2 T&S price would cause a higher operating cost of running carbon capture process thus a higher carbon price is needed if targeted carbon capture level is to be maintained.