[tuatoru]

Combined cycle gas turbine generators use a steam turbine as a second, downstream method to recover exergy from the exhaust of the main gas turbine.

CCGTs are expensive. Simple gas turbines that are used to meet daily demand peaks are relatively cheap; as GP said they're basically stationary jet engines.

To me it's kind of bizarre that money is so cheap at present, but somehow it's still too costly to use it to invest in things with a delayed payback.