I would not be surprised to see a special license needed to operate gas turbines. That's some serious moving parts there.

The main ADVANTAGE of a turbine over a reciprocating gas combustion engine, beside the relative power-to-size ratio, is that, despite the added complexity of control, there is only one moving part so less to wear out. That however does not discount the other argument about sevicing, because that one moving part is a quantum leap more critical and specialized. It's jusst that as he said, when you get into large systems, the same amount of power from a reciprocating engine would require a lot wear parts like cylinders, pistons, rings, valves, cams, rockers, crankshaft bearings, timing belts, distributors etc. etc. etc. So if you are a large power gen facility with a high revenue power source where reliability is critical but you can afford the critical scheduled maintenance by a specialized crew, a turbine makes sense.

But like he said. if you want to just go crab a shade tree mechanic in a pinch and have him change parts on an engine that is similar enough to a car engine that anyone with basic mechanic training can understand it, do NOT go with a turbine.

In addition to the quality answers above:

Fuel availability is a major concern when choosing generators. Which will run best with the fuel you have? Would it be advantageous to change fuels as necessary?

My company is in the process of moving a turbine that has been running on natural gas for years to another location where it will run on diesel. We had an easy supply of natural gas at the first location and the unit ran during the peak season, it's new home it will be kept as a standby generator in case of transmission failure or high localized demand.

Additionally, some turbines can be quite small and run with out much hassle. The aviation industry often uses small turbines running diesel, or kerosene or jet fuel to provide power for aircraft on the ground undergoing maintenance or loading cargo/passengers.

Drew K

Some times the gas and its caloric value also decide what we should use. For an example;the blast furnace gas in steel plant has very low calorific value and it is not suited much for turbine, whereas engine may be easily feasible.

Besides the many quality answers above, one more thing I would add in favour of turbine is its specific weight (kg/kW), which is many times lower than an engine.