A combined cycle power plant comprises a combustion turbine generator, another heat source in addition to the combustion turbine generator, a steam power system, and an energy storage system. Heat from the heat source, from the energy storage system, or from the heat source and the energy storage system is used to generate steam in the steam power system. Heat from the combustion turbine generator exhaust gas may be used primarily for single phase heating of water or steam in the steam power system. Alternatively, heat from the combustion turbine generator exhaust gas may be used in parallel with the energy storage system and/or the other heat source to generate steam, and additionally to super heat steam. Both the combustion turbine generator and the steam power system may generate electricity.