Abstract: A method and system for augmenting the output of a combined cycle power plant having a base gas turbine (22) driving a generator (36) and a heat recovery steam generator (42) that recovers exhaust heat (30) from the base gas turbine (22) to drive a steam turbine (60). A complementary gas turbine engine (12) is added to the power plant to drive a complementary generator (14). The exhaust (A, B, C) of the complementary gas turbine (12) is merged into the flow path of exhaust gas (30) from the base gas turbine (22) upstream of a selected one or more heat exchangers (46, 50, 52) in the heat recovery steam generator (42). Such a complementary system (10) may be used together with supplemental duct burners (48) in a hybrid augmentation embodiment.