Retrofit equipment includes an auxiliary gas turbine unit including an auxiliary compressor for compressing ambient air to produce compressed air, a solar collector that receives the compressed air for heating the same too produce heated compressed air, and an auxiliary turbine coupled to the auxiliary compressor and to an auxiliary generator for expanding the heated compressed air and driving the auxiliary compressor and auxiliary generator thereby producing power and hot exhaust gases. A boiler has heat exchanger coils containing water and receives hot exhaust gases for vaporizing water in the coils and producing steam. A condensor condenses the expanded steam to condensate, and a pump returns the condensate to the boiler.