A power generation system may include a generator, and a gas turbine system for powering the generator, the gas turbine system including a turbine component, an integral compressor and a combustor to which air from the integral compressor and fuel are supplied, the combustor arranged to supply hot combustion gases to the turbine component, and the integral compressor having a flow capacity greater than an intake capacity of at least one of the combustor and the turbine component, creating an excess air flow. A turbo-expander may also power the generator. A first control valve control flow of the excess air flow along an excess air flow path to an inlet of the turbo-expander. An educator may be positioned in the excess air flow path for using the excess air flow as a motive force to augment the excess air flow with additional air. A discharge of the turbo-expander is supplied to an inlet of the integral compressor.