The heat is on for electric utilities to power air conditioners amid the hottest temperatures of the summer so far in Chattanooga this week.
As the July heat pushed Thursday's high temperature to 98 degrees in Chattanooga, the Tennessee Valley Authority used new-fired combustion turbine plants started up this week on an abandoned coal plant site in North Alabama to help meet the summertime power demand peak.
Three new natural gas-fired generators began power production for the first time Tuesday at the former Colbert coal plant on Pickwick Landing Lake in Alabama, supplying 750 megawatts of electricity to meet the power demands of more than 400,000 homes. The $500 million addition of the new gas plants at Colbert, which began two years ago, was completed four months ahead of the original schedule and under the initial budget price, TVA spokesman Scott Fiedler said.
"Like magic, we pressed the button, and we used two of the three units (Thursday)," Fiedler said in an email Friday. "The Colbert team is very proud to see them operating and powering homes and businesses during this heatwave and for years to come."
TVA reached its highest summertime peak in more than a year Thursday when TVA delivered 30,680 megawatts of electricity across the Tennessee Valley at around 5 p.m. Central time, when the average temperature in TVA's service territory was 95 degrees. TVA forecasted an even higher peak Friday of 30,950 megawatts as homes and offices cranked up air conditioners to stay cool amid the hot temperatures.
The Tennessee Valley has not yet had the record high temperatures of other regions in the United States this summer, but the National Weather Service predicted the high in Chattanooga on Friday would reach 97 degrees with a heat index that measures both temperatures and humidity to make it feel like 102 degrees.
"We haven't had as much really hot weather as most of the country this summer, but we're seeing the seasonal heat and high pressure systems push up temperatures this week," Sam Roberts, a meteorologist with the National Weather Service in Morristown, Tennessee, said Friday in a telephone interview.
Debate over gas plants
Although environmental leaders and the Biden administration have been critical of TVA building more fossil fuel generation, Fielder said such gas plants are far cleaner than the coal units they replace and help supplement TVA's growing use of solar power to keep the lights on during power peaks when solar power is not always available.
TVA shut down the last of its coal units at the Colbert Fossil Plant in 2016.
"The Colbert project reinforces TVA's commitment to cleaner generation while providing flexibility, responsiveness and reliability for the power grid," Fiedler said in a news release about the new gas plants. "Natural gas generation allows TVA to add more solar energy to the grid because it can generate power to make up for the time when the sun does not shine."
With three nuclear power plants and 29 hydroelectric dams, TVA produces most of its electricity from carbon-free sources, and it plans to phase out the last of the 59 coal-fired units it once operated within the next 12 years. But natural gas still produces about a fourth of all TVA power, and TVA is planning during the next decade to build up to to 7,000 megawatts of new natural gas generation -- enough dispatchable electricity to power more than 3.8 million homes.
TVA also plans to add 10,000 megawatts of solar by 2035, but the utility is adding new gas to help meet projected growth in electricity demand due to the growth of electric vehicles and to help generate power when the sun doesn't shine or the wind doesn't blow.
TVA is building 3,450 megawatts of new fossil gas plants in just the next three years, including another 750 megawatts of new power from gas-fired units scheduled to come online later this year at the Paradise plant in Kentucky.
Environmental groups object to TVA's continued use of fossil fuels and the long-term investments in the gas plants and gas pipelines built to supply the new gas-powered generators.
The Sierra Club, Appalachian Voices and the Center for Biological Diversity joined together in June to file a lawsuit against TVA to try to block the latest plans for more gas power plants to replace the coal units at the Cumberland Fossil Plant in Cumberland City, Tennessee.
The lawsuit filed in Nashville claims TVA violated the National Environmental Policy Act by prematurely committing to the gas plant, failing to fully study cleaner alternatives and failing to assess the climate harm and economic impact of the proposal.
"Tennessee Valley ratepayers have been asking for more renewable energy and energy efficiency from TVA, and the market along with private energy providers have been moving forward with a clean energy transition," Amy Kelly, Sierra Club's senior campaign representative for the Tennessee Valley Region, said in a statement. "We know that renewables with battery storage and robust energy efficiency continue to beat out fossil fuels in cost around the country, so a federal agency should be held accountable when it fails to meet the most basic requirements of the National Environmental Policy Act."
The lawsuit says the Cumberland gas plant would pump out an estimated 2.8 million tons of climate-warming pollution every year for decades to come.
TVA has pledged to become carbon free by 2050, but President Joe Biden says he wants electric utilities to be carbon neutral by 2035 by shifting more quickly to solar, wind, nuclear and other carbon-free generation.
TVA President Jeff Lyash told a congressional committee last month that the federal utility "is going as far and as fast as we can" to limit carbon emissions. But he said TVA will continue to need some natural gas generation to meet peak power demands, especially with electricity usage projected to double by 2050 in the Tennessee Valley due to population and electric vehicle growth.
In a recent visit to Chattanooga, U.S. Energy Secretary Jennifer Granholm said she thinks TVA can do better in cutting its use of fossil fuels to become carbon free by 2035.
"TVA is also very incentivized now to be able to make sure that we get to that clean energy future," Granholm told the Times Free Press.
Contact Dave Flessner at dflessner@timesfreepress.com or 423-757-6340.
TVA / TVA Colbert employees monitor the units in the control center.