Abstract: The gas turbine system comprises an aeroderivative gas turbine engine and a load having a shaft line drivingly coupled to the gas turbine engine. The gas turbine engine comprises a high-pressure turbine section and a high-pressure compressor section, drivingly coupled to one another by a first turbine shaft. The gas turbine engine further comprises an intermediate-pressure turbine section and a low-pressure compressor section, drivingly coupled to one another by a second turbine shaft, coaxial to the first turbine shaft (91). Furthermore, a combustor section is provided, fluidly coupled to the high-pressure compressor section and to the high-pressure turbine section. A free power turbine, supported by a third turbine shaft which is mechanically uncoupled from the first turbine shaft and the second turbine shaft, and is directly coupled to the shaft line, such that the shaft line and the third turbine shaft rotate at the same rotational speed.