With an increase in renewable energy generation, thermal power generation has been switched to standby power in various parts of the world. Ammonia, one of the storage and transport media for H2, is produced in a highly efficient oxyfuel integrated coal gasification combined cycle (IGCC) system with CO2 capture, for the future hydrogen-using society. Using ammonia as an industrial raw material, agricultural fertilizer, and transportation fuel, energy systems can be established by combining renewable energy and thermal power generation. Therefore, it is possible to simultaneously construct a thermal power supply system suitable for backup power source owing to the fluctuation of the renewable power generation and to improve the availability of the thermal power plant and the load-leveling. This will serve as an incentive to build a future zero-emission thermal power plant. In this study, an oxy-fuel IGCC power generation coproduced with ammonia and CO2 capture is conceptually proposed. Furthermore, the features and challenges of a gas turbine that fuels CO2-free NH3 are investigated. In particular, the combustion exhaust characteristics of ammonia/oxygen-fired semiclosed cycle gas turbine combustor in comparison with those of the conventional fuels are characterized through a kinetic analysis.