A fuel heating system for a gas turbine system, a method thereof and a power generating system are provided. The system includes a boiler for generating steam, a HRSG independent of the boiler, and asingle fuel heat exchanger structured to operate using steam or water as the heating medium. A control valve system selectively delivers the heating medium to the second passage of the single fuel heat exchanger as one of: the steam from the boiler and the hot feedwater from the HRSG.