A power plant includes a gas turbine having a combustor downstream from a compressor, a turbine disposed downstream from the combustor and an exhaust duct downstream from an outlet of the turbine. The combustor includes an extraction port that is in fluid communication with a hot gas path of the combustor. The extraction port defines a flow path for a stream of combustion gas to flow out of the hot gas path. The exhaust duct receives exhaust gas from the turbine outlet. A coolant injection system injects a coolant into the stream of combustion gas upstream from the exhaust duct such that the stream of combustion gas blends with the exhaust gas from the turbine within the exhaust duct and forms an exhaust gas mixture within the exhaust duct. A heat exchanger is disposed downstream from the exhaust duct and receives the exhaust gas mixture from the exhaust duct.