Gas is the first choice, both economically and environmentally.
From now on, TVA normally will use fuel oil, or diesel, in combustion turbines only when gas is not available. Fuel oil also is used to restart the boilers of all 59 TVA coal-fired units, so every fossil plant needs a supply. However, installation of four new combustion turbines each at Gallatin and Johnsonville required a switch to a different fuel-oil supply. The permit requires TVA to use only low-sulfur fuel oil at those sites. But because of milder temperatures, TVA didn't have to use its combustion turbines as much as expected last year.