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Old 10-07-2008, 08:09 PM   #31 (permalink)
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Originally Posted by jamesqf View Post
If indeed they are inefficient, then why are so many used in utility power generation? Sure, that's at a different size scale than an auto or light aircraft turbine, but if an IC engine were indeed more efficient than a turbine, then why are these applications not using large "diesel" engines running on natural gas, instead of gas turbines?

Because it is impractical to use a 56,000 horsepower diesel engine in the power industry. The power industry also uses the gas turbine's exhaust heat to provide heat to a HRSG (Heat recovery steam generator) to make LP and HP steam to power steam turbines. This would be called a combined cycle. THEN it all becomes more efficient if you look at it as an entire power plant, rather than just a single gas turbine. It's a little more complicated than that, but hopefully you get the idea.

Other reasons for aero gas turbines is that they can cycle loads quicker than frames or coal plants and can be used for frequency control of the grid, and be available as peakers.

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