An IGCC (integrated gasification combined cycle) is a widely used electrical power generation system that allows for a variety of feedstocks with high efficiencies. In this study, a 300 MW class IGCC plant was simulated using the PRO/II software package, and thermodynamic analysis was performed. The simulated results were compared to the basic design data for a 300 MW Class IGCC demonstration plant to evaluate the validity. Since changing the feed coal grade causes one of the most significant issues in operating an IGCC system, this study investigated the coal sensitivity of the system by examining two different grade coals (Coal #1: 25,439 kJ/kg and Coal #2:21,338 kJ/kg). Their net powers were determined via thermodynamic analysis and by evaluating the power generation and power consumption and were found to be 324.4 MW and 279.1 MW for Coal #1 and Coal #2. Based on the inlet coal energy, the overall efficiencies under the same conditions were found to be 40.38% for Coal #1 and 41.42% for Coal #2. This paper presents Sankey diagrams for the energy and exergy flow associated with the first and second laws of thermodynamics, and discusses how they influence the major components of the IGCC. As a final point, in order to elucidate the preferable coal in terms of financial sense, economic analysis was carried out on the viability of the cases considered. The costs of electricity for Coal #1 and Coal #2 were evaluated as 0.07 US$/kWh and 0.08 US$/kWh. Hence, Coal #1 can confidently be chosen as a more economic option even though, it costs relatively higher than the other Coal #2. (C) 2013 Elsevier Ltd. All rights reserved.