Home Energy system After coal, does TVA need more natural gas? New study says renewables are cheaper and can be just as reliable

After coal, does TVA need more natural gas? New study says renewables are cheaper and can be just as reliable


The Tennessee Valley Authority is proposing to replace its largest coal-fired plant, at least in part, with natural gas generation to reduce both its carbon emissions and operating costs while maintaining reliable electric service.

But environmental groups and TVA’s biggest long-term customer say the federal utility could do more to save money and protect the environment by ditching all fossil fuels in favor of renewable power generation programs, energy storage and energy efficiency.

The latest power battle for TVA focused last week on the environmental review TVA is completing this summer for the future of the Cumberland Fossil Plant. After 54 years of operation as TVA’s largest coal-fired plant, the two-unit Cumberland plant on Lake Barkley is nearing the end of its useful life. To replace part of the aging plant’s 2,470 megawatts of power generation, TVA is conducting an environmental impact study, and in April utility officials said the preferred option was to build a 1,450 megawatt natural gas combined cycle plant on the Cumberland. to place.

The gas-fired plant is expected to reduce carbon emissions to less than a quarter of what the current coal-fired plant emits and the study says it would be “beneficial” to the environment and the reliability of electric service. TVA’s environmental review indicated that a new gas-fired plant would enable the future integration of 10,000 megawatts of solar generation that TVA plans to install by 2035 and help accelerate the retirement of Cumberland’s coal-fired units.

But a new gas plant would require the construction of a 32-mile pipeline and continue at least some carbon emissions into the atmosphere. These greenhouse gases have been linked to global climate change by environmental scientists.

A study commissioned by the Sierra Club calculates that TVA could achieve cheaper and cleaner generation through a combination of solar, wind, battery storage and energy conservation measures. The Sierra Club retained Synapse Energy Economics, Inc. to model the TVA system and the study found that a clean portfolio approach would save TVA $3 billion more over the next two decades than the construction of new gas generation to replace part of the Cumberland coal-fired power station.

The 32-page economic analysis says building gas to replace coal is “risky,” as falling costs of renewable energy generation and electricity storage and rising natural gas prices will likely make unprofitable and useless gas power plants in the future.

“Any new gas-fired capacity built over the next decade will likely result in stranded assets in which a generator with remaining depreciable life has been rendered uneconomical to consumers,” the Synapse Energy study concluded. “This discovery supports resource planning that provides solar, wind, storage and energy efficiency as early as possible in the 2020s.”

The study says that for TVA to meet White House goals of building a carbon-free electric system by 2035, the federal utility must “act decisively to retire existing coal, minimize reliance on new gas, and commit to increasing volumes of renewables, storage and demand.” – secondary resources.

“Synapse, a well-respected energy analytics company, has discovered what we’ve long thought: TVA can quickly transition from coal-fired power plants to renewable energy to better meet its charter for environmental stewardship and affordable energy for the Tennessee Valley.” Amy Kelly of the Sierra Club’s Beyond Coal campaign, said in a summary of the new study.


TVA received final public comments last week on the future of its Cumberland fossil plant. TVA’s preliminary conclusion was that some natural gas production is required at the site to help ensure electricity delivery when the sun is not shining, the wind is not blowing or other TVA power plants may be inactive due to weather, refueling or equipment issues.

To meet winter peak demands on frigid winter mornings before the sun rises and solar generation begins, power generation is needed that can be quickly put on the grid. TVA plans to add more batteries and potentially more hydro-pumped storage generation, but these are not yet as profitable as gas-fired combined-cycle plants, according to TVA President Jeff Lyash.

“We’re moving towards a cleaner system, but we’re careful not to sacrifice power supply reliability or resilience,” Lyash said in an interview with The Times Free Press earlier this year. “It is in all of our interests to remember that in addition to being clean, the system must be affordable, reliable and resilient. If you sacrifice any of these, it is not a sustainable solution. “

For more than two decades, TVA has delivered its electricity more than 99.999% of the time, avoiding major power outages like those that left 4.5 million people without power last year during a winter storm in Texas or the Northeast and Midwest blackout in 2003 that cut off power to 50 million Americans.

TVA currently generates around 26% of its electricity from natural gas-fired power plants, but most of TVA’s electricity now comes from relatively carbon-free nuclear power, hydroelectric dams and solar parks.


Environmental groups and others argue that with more energy efficiency programs, time-of-day pricing plans and investment in energy storage facilities, TVA can transition to a carbon-free portfolio. without sacrificing reliability.

“A diverse, customer-focused clean energy system is a win-win,” said Maggie Shober, director of research at the Southern Alliance for Clean Energy, in a statement submitted to TVA on Cumberland’s future. “This lowers customer bills, reduces pollution and greenhouse gas emissions, and improves resilience to extreme weather conditions. TVA must embrace a clean energy portfolio to replace Cumberland rather than lock customers into ever-volatile fossil fuels.

Shober said TVA has the second-highest planned gas development of any major utility with 4 gigawatts of new gas capacity planned by 2030.

“TVA is horribly irresponsible,” Sudeep Ghantasala of the Sunrise Movement Nashville chapter said in an announcement of the group’s opposition to TVA’s plans for more natural gas production. “The permitting process for the gas pipeline started months ago. TVA claims it was to speed up the process if they chose the gas-fired combined cycle plant. Why didn’t they start the same process for the solar alternative, and better yet, looked at distributed solar power, energy efficiency and demand response that could kick in earlier and even reduce demand for large-scale projects?”

Robin Brandon, a retired TVA shift operations manager who is now mayor of Stewart County where the Cumberland Fossil Generating Station is located, said he thinks most local residents understand that the coal-fired power plant in 54 years old is nearing the end of its useful life and will eventually be closed.

“We are concerned about the job losses that the Cumberland closure will cause, but we understand that natural gas will likely continue to produce there, retaining some jobs and our VAT-equivalent payments,” Brandon said during the interview. ‘a telephone interview.

But earlier this month, TVA’s largest long-term customer, Nashville Electric Service, and Nashville Mayor John Cooper sent letters and resolutions to TVA urging the federal utility to pursue renewable fuels. rather than natural gas to replace the electricity generated by the Cumberland Fossil Plant when the coal facility is shut down.

“Any plan that would establish a new gas pipeline or draft Nashville into decades of carbon-polluting methane is unacceptable,” Cooper wrote in the letter to TVA. “The City of Nashville is calling on TVA to be a leader in addressing the existential threat of climate change.”

Contact Dave Flessner at [email protected] or 423-757-6340. Follow on Twitter at @dflessner1