Potential assessment on gas turbine combined cycle with alternative gaseous fuel from coal gasification

In the 21st century, fossil fuels will remain the mainstay of energy production, while natural gas combined cycle (NGCC) features environmental benignity and high efficiency. Hence, it is desirable to assess the potential of NGCC for power generation, in which gas turbine (GT) is operated with alternative gaseous fuel from coal gasification, since coal is the most abundant fossil fuel. System-level analyses for NGCC plants, combining advanced GTs with various fuels, are performed in this study. The commercial chemical process simulator, Pro/II^® V8.1.1, is implemented to build the simulation models. This work further performs various analyses as the basic and feasibility cases. The former is the benchmark case verified with the reference data of an operating NGCC power plant located in northern Taiwan. The latter introduces a feasibility study with advanced GTs and actual parameters in Taiwan. Alternative fuel, including synthetic natural gas (SNG) or a mixture of SNG and syngas, is fed to combined cycle for evaluating the overall performance. The results indicate that the system output or efficiency in either case is slightly (2–3 % points, LHV) lower than the counterpart in the benchmark one. In Taiwan, the natural gas price is much higher than that of coal, and results in higher idle capacity of NGCC. The advantage of adopting SNG to NGCC is that it could increase the capacity factor and subdue the environmental impact of the energy portfolio. The outcome of this study indicates a possible means to utilize coal more efficiently and reduce emissions.