Multi-mode operation of Combined Cycle Gas Turbines with increasing wind penetration

As power systems evolve to incorporate greater penetrations of variable renewables, the demand for flexibility within the system is increased. Combined Cycle Gas Turbines (CCGTs) are traditionally considered as inflexible units but those which incorporate a steam bypass stack are capable of open-cycle operation. Facilitating these units to operate in open-cycle mode is shown to improve system reliability and reduce emissions. It also yields benefits for the generators themselves via increased revenues (in some circumstances) and reduced cycling.