A co-generation process for a regenerator in an FCC system having a reactor and a regenerator includes the steps of introducing flue gas from the regenerator into a heating unit at a first location of the heating unit, and introducing an oxygen/fuel gas mixture into the heating unit at a second location of the heating unit apart from the first location, and combusting the oxygen/fuel gas mixture in the heating unit at the second location to form a hot combustion gas. The process further includes the steps of combining the hot combustion gas and the flue gas at a third location of the heating unit apart from the first location to produce heated flue gas, heating water and/or steam with the heated flue gas to produce a heated steam, and introducing the heated steam into a turbine to extract energy from the heated steam.