The Mystic power plant in the United States, which generates 1,688 MW of electricity, has undergone successful commissioning and began commercial operation in June 2003. Mystic, located in Boston, is owned by Excelon and comprises two blocks of M501G 2-on-1 configuration. MHI's scope of supply is four M501G gas turbines, two steam turbines and four HRSGs coupled with a sophisticated SCR system.
The reason why this plant is unique for MHI is that MHI supplied the Mystic power plant as the first combined cycle plant in the U.S., and furthermore, MHI applied the most updated G technology as well as a state-of-the-art sophisticated SCR system (Selected Catalyst Reactor: De-NOx System). An M501G gas turbine is coupled with steam cooling combustors to enhance firing temperature while maintaining well-controlled metal surface temperatures and low NOx emissions. This system also enhances efficiency of the bottoming cycle by supplying high-temperature steam to the MHI steam turbines. MHI has been operating the M501G in Japan since 1997, and, outside Japan, the M501G combined cycle plant in the Philippines has also been running since 2002 with high efficiency and reliability.
The Mystic SCR system, which reduces NOx and NH3 slip of less than 2.5 ppm. SCR system was designed by MHI and sets of catalyst were manufactured by Cormetech (joint venture of MHI and Corning).
The successful completion of Mystic power plant will supply reliable electricity with environmentally benign emissions at a time when energy policy and the needs of the United States are a crucial topic among government, power producers and consumers.