Rotor System Inertia

[RotaryG]

For a standalone captive power plant (no public grid nearby) how important is the polar moment of inertia of the rotor system important for a 200 MW gas turbine power plant? Would industrial heavy duty gas turbine provides better inertia than aircraft derivative gas turbine? Or can we have consider any of the gas turbines without having to worry about the inertia? Any feedback on actually designing/ operating (island mode) similar size power plant with aircraft derivative gas turbines is appreciated.

Thanks in advance.