"combined cycle combustion turbine power plants"
How many of these do we have operating in the U.S.?
I don't have any numbers but I'd guess hundreds. That's one of the reasons for the increase in natural gas prices. GE came out with a single unit @200MW in the early 90's. The market took off when a power broker in the Midwest reneged on contracts and a utility had to go to the spot market in the summer time to buy a lot of power. They had to pay several dollars a kilowatt to get the power. That scared the hell out of a lot of utility executives in low reserve situations.
Between Enron and another company (possibly Fluor), GE had received orders for over 200 units. Of course when Enron tanked, a lot of those orders were cancelled. Still a lot have been installed around the country. If you've read anything about a power plant under construction or proposed, it's probably a combustion turbine.