Actually, it is generally accepted that once the site's power output goes above 50 Mw gas turbines are so superior, particularly regarding maintenance, that nothing else makes any sense.
Engines 101 for those new to the subject:
1. Another name for a 'reciprocating engine' [which is a fancy name borrowed from the aircraft industry] is 'piston engine' - in power stations they are just a bigger version of the engines still used in most cars. Pistons and valves slapping around - up down, up down, translated into rotational motion at the crankshaft. No surprises, 150 years of development. Pretty well understood.
2. The word 'turbine' comes from the Latin meaning 'wheel'. Turbines are named according to the substance driving the wheel e.g. water, wind, steam, gas. Sometimes gas turbines are called 'combustion turbines'. This better captures what is going on - that it is the products of a combustion process, the gases, that drive the turbine. Both the turbine 'hot end' and the rest of the engine is optimised for that.
Gas turbines can use a wide range of fuels, liquid or gaseous. Aircraft engines run on a standard type of kerosene called Jet A1 or in North America a slightly different spec called Jet A. But so long as you can get it down a tube into the combustion chamber, a gas turbine will pretty much run on anything that will burn, obviously including natural gas.
3. For the power industry, gas turbines come in two broad types. Simple cycle, aka open cycle gas turbines release the still hot gases out of the turbine back into the atmosphere .
Compound cycle gas turbines put those hot exhaust gases to further use by passing them through a heat exchanger to heat water to raise steam which is then used to drive a steam turbine to drive an additional electrical generator. Compound cycle GTs have about 50% thermal efficiency, quite often more. Simple cycle usually have high 30s to low 40% efficiency.
The main difficulty with compound GTs is that they can be fiddly to start and the start has to be done gradually, think one to two hours, so they are not generally suitable for peaking power plants. I suppose you could keep them running all day ready to be brought online when asked but that would be very expensive and wasteful. Hard to make a profit doing that.
For simple cycle from the time you push the button [metaphorically] it takes about 45 seconds for the start sequence to bring the engine to idle [or is that Idle?], then large GTs need around three minutes stabilised at or close to idle to warm up all the hot parts in a controlled manner, otherwise you will soon have big problems, and after that you can bring them up pretty quickly to full power. So say five minutes nominally from cold start to full output.
There have been around 50 years of hard won experience, millions and millions of operational hours, with large gas turbines since simple cycle versions were introduced into aviation in the late 1960s. You'll also commonly find them in warships and other marine applications, as pipeline pumps etc. They are extremely reliable beasts these days and all modern ones [that I know of] have remote telemetry for condition monitoring that usually goes to the supplier's centralised support centre. These centres tend to be in the US, but so long as the data has alternative transmission pathways and is properly encrypted this works seamlessly.
I've concentrated on gas turbines here because despite everyone seeing them overhead and around airports all the time, few people seem to know much about them. Even the aircraft you see around these days with propellors, Dash 8s, Saab 340s, ATRs etc are all just gas turbines driving a propellor.
Fact is, the power generation industry is so competitive now that it would not be difficult to purchase a full turnkey solution to the rather simple problem of supplying and maintaining a peaking power station. Doesn't really matter what's inside the box, but I'm biased towards turbines, if that isn't self evident.
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