The Tennessee Valley Authority, which has boosted its power generation from natural gas after shuttering more than half of its aging coal fleet, completed its biggest gas plant upgrade in TVA history this month as one of 69 gas projects to get ready for colder winter weather ahead.
John Sevier Combined Cycle gas plant, which was built in 2012 to help replace the closed four-unit coal plant built originally on the site in 1957, returned to service in early December after a 10-week outage that was the most extensive outage to date of any TVA gas plant.
“We left no component untouched in overhauling this plant to make sure it provides reliable power this winter and for years to come,” said Dustin Watson, manager of the plant located on the Holston River near Rogersville, Tennessee.
Outage activities included upgrades, refurbishments and major maintenance on all three combustion turbines, one steam turbine and their associated generators, he said. TVA spokesman Scott Brooks said an additional 200 contract workers were onsite during the outage.
The 871-megawatt facility can use natural gas or No. 2 fuel oil for combustion and is among eight such combined cycle gas plants operated by TVA. The federal utility also operates nine natural gas combustion turbines. Collectively, gas-fired generation comprises 26% of TVA’s overall power generating capacity. In fiscal 2021, the gas units produced 21% of TVA’s total electricity.
TVA has boosted its use of natural gas after phasing out more than half the 59 coal-fired units it once operated. The gas plants emit less carbon and burn cleaner than coal, but environmental groups concerned about global warming have urged TVA to phase out all of its fossil fuel generation in the next decade and a half.
TVA’s power profile
TVA’s electricity generation capacity is comprised of a diverse array of fuel sources from more than 50 power generating plants across its seven-state region for a total capacity of 33,727 megawatts.* Nuclear — 39%* Natural gas — 26%* Coal — 19%* Hydro — 11%* Solar and wind — 3%* Energy efficiency — 1%Source: Tennessee Valley Authority
TVA contends that gas-fired plants are an efficient source of power that can be quickly activated and used to help meet power peaks, especially when the sun doesn’t shine, the wind doesn’t blow or a nuclear reactor shuts down unexpectedly.
TVA is moving forward with plans to build gas-fired combustion turbines at its former coal plants in Paradise, Kentucky, and Colbert, Alabama.
TVA has pledged to phase out all of its coal power generation within the next decade and a half.
TVA has already shut down 34 of the 59 coal-fired units it once operated, including closing its Widows Creek, Colbert, John Sevier, Allen, Paradise and Johnsonville coal plants in the past decade. TVA is preparing to shutter its Bull Run Fossil plant by 2023 and, subject to environmental studies and board approval, is planning to ultimately shut down its Cumberland, Gallatin, Kingston and Shawnee coal plants by 2035.
TVA has set a goal of being carbon free by 2050.
“Natural gas is a bridge that will help ensure reliability as TVA transitions towards the energy system of the future,” said David Bowling, vice president of gas and hydro for TVA.
– Compiled by Dave Flessner