The present invention provides a method and apparatus for separating air and generating electrical power. A compressed air stream produced in a main air compressor is introduced into an air separation unit that cryogenically rectifies the air into component products. During turndown conditions of the air separation unit, a combustion air stream formed from all or part of the compressed air stream is introduced into a combustor in which a fuel is combusted to produce a heated and pressurized combustion stream. Such stream is introduced to a turbine connected to an electrical generator to generate electrical power. The combustion air stream can be saturated with moisture to increase power output. Further, the combustion air stream can also be preheated with an exhaust of a gas turbine.
