Abstract: A multi-stage method and apparatus for cooling the inlet air of internal combustion engine and gas turbine prime movers associated with various load applications comprising: generating and providing a multi-stage refrigerated cooling system associated with the air inlet of internal combustion engine and gas turbine prime movers which provides thermodynamic efficiencies in accordance with a divided psychrometric inlet air cooling path enthalpy curve; cascading the cooled refrigerant from stage to stage to cool primary or secondary refrigerant from a first cooling stage as a precooling heat transfer coolant to exchange against and subcool subsequent stages of primary or secondary refrigerant for cooling to the desired temperature; energizing power means to drive the prime mover and refrigerant cooling system; and adjusting the power means based on current energy costs to optimize net revenues to produce electricity or useful work from the prime mover application.