ABSTRACT
High perpetration of renewable energy resource (RES) leads to significant increase in the system flexibility. As a vital component in the electricity system, thermal plants may support the cost-effective integration of RES through enhancing their flexibility. This chapter presents a detailed discussion on the various flexibility features and the potential improvements associated with Combined Cycle Gas Turbine Plants (CCGTs), including ramp rate, minimum stable generation, frequency response capability, commitment time, idle state capability and part-load efficiency. The economic and environmental benefits of CCGTs with enhanced flexibility are quantified by simulating annual operation of two representative systems. An advanced stochastic unit commitment and economic dispatch tool is applied in order to capture the variability, uncertainty and limited inertia capability associated with RES. Comprehensive sensitivity studies are also carried out to understand the impact of scheduling methods, forecasting errors, system inertia reduction and carbon prices on the value of CCGTs with enhanced flexibility.
