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 are
traditionally considered as relatively inflexible units, but those
which incorporate a steam bypass stack are capable of opencycle
operation. Facilitating these units to also operate in opencycle
mode can benefit the power system via improved system
reliability, while reducing the production needed from dedicated
peaking units. The utilization of the multi-mode functionality is
shown to be dependent on the flexibility inherent in the system
and the manner in which the system is operated.