Wiki: The 605 MW General Electric 9HA achieved a 62.22% efficiency rate with temperatures as high as 2,800 °F. For 2018, GE offers its 826 MW HA at over 64% efficiency in combined cycle due to advances in additive manufacturing and combustion breakthroughs, up from 63.7% in 2017 orders and on track to achieve 65% by the early 2020s.
That’s one of the reasons why I believe technological advancement is the key to having less impact on the environment, not bigger government.
The switch to high efficiency combustion turbine / combined cycle is what has driven U.S. CO2 emissions to low levels. Natural gas emits half the CO2 of coal and combined cycle plants have almost double the efficiency of coal, so they put out 1/4 the CO2 of coal.
I actually think it is a,dreadful mistake to use gas to make electricity. Save gas for home and commercial heating and for feedstock to petrochemical processes. It is way too valuable to make electricity with; generate power with nukes and coal.
Also, reducing CO2 is just plain stupid and a huge waste of resources. CO2 should not be driving energy policy. It is causing the misallocation of resources everywhere.