The Tennessee Valley Authority has completed a $475 million power upgrade at its oldest and biggest nuclear power plant that helped boost the plant's output by 14% and boosted TVA's overall noncarbon production of electricity to 58% of its power generation this spring.

Over the past four years, by making more than 200 equipment modifications to the three reactors at its Browns Ferry Nuclear Plant, TVA added 465 megawatts of additional power at Browns Ferry, increasing its capacity enough to supply the energy needs of another 280,000 homes.

"We're very proud of our program at Browns Ferry and I think it was a great effort by our nuclear team," TVA President and CEO Jeff Lyash said in a conference call with industry analysts last week.

Combined with the addition of a second reactor at its Watts Bar Nuclear Plant two years ago and additional solar power generation and energy efficiency, Lyash said he expects TVA to be able to reduce its carbon emissions by 70% from the 2005 levels by 2030.

But Lyash said achieving zero-carbon generation at TVA will require more cost-effective alternatives to TVA's ongoing generation now coming from its remaining coal and new natural gas plants.

"Our objective is to lower our carbon intensity as much as well as can, but doing it cost effectively," Lyash said. "For the customers we serve in the Tennessee Valley, the price and reliability of electricity is vital to them. We'll look for every opportunity to cost-effectively reduce the carbon intensity of our fleet."

TVA plans to shut down the final coal unit at its Paradise Fossil Plant in western Kentucky by 2020 and shutter the Bull Run Steam Plant near Oak Ridge by 2023. But its integrated resource plan for the next 20 years envisions TVA continuing to get about 15% of its generation from coal and 20% or more from natural gas.

Despite the dramatic drop in emissions of CO2 from TVA and other Southern utilities in the past decade and a half, a new study by Southern Alliance for Clean Energy suggests that utilities in the Southeast are a long ways from achieving the zero-carbon emissions sought by many environmental groups concerned about C02 emissions adding to global warming.

"Current utility plans show a continuing declining trend in the future in CO2 emissions, but that is going to level off within the next few years and potentially even begin to tick upward by 2030," said John D. Wilson, deputy director for regulatory policy at the Southern Alliance for Clean Energy.

Heather Pohnan, the energy policy manager for Southern Alliance for Clean Energy, said TVA's carbon emissions dropped 51% from 2005 to 2018, driven primarily by a reduction in coal generation.

Coal accounted for nearly two thirds of TVA's power in the 1980s but dropped to only 18% last year. TVA's new integrated resource plan, which TVA directors are scheduled to vote on at their next meeting on Aug. 22 in Knoxville, would result in emissions that are 57% below 2005 levels in 2038, Pohnan said.

"That means TVA reduced emissions by 51% in 13 years but only plans to get another 6 percentage points of reductions in the next 20 years," she said in a new 42-page report "Tracking Decarbonization in the Southeast."

Lyash said TVA is adding to its solar power, but the biggest carbon cuts in the near future are likely to realized by efficient generation of its nuclear fleet.

To meet the demand of new Google and Facebook data centers, TVA contracted for 674 megawatts of solar power a couple of years ago. In April, a 53 megawatt solar facility came online in Millington, Tennessee — the largest solar installation in the state. Also in April, TVA announced a request for proposals for additional 200 megawatts of power. In May, TVA and Silicon Ranch flipped the switch on another 5 megawatt community solar project near Telford, Tennessee.

But solar remains only a tiny share of TVA's overall generation. Nuclear power is expected to produce about 40% of TVA's electricity and could generate even more if TVA decides to proceed with small modular reactors in Oak Ridge.

"The most important thing that we can do in terms of maintaining our low-carbon generation is to operate our existing nuclear fleet at the highest levels of performance and to extend the lives of those units, if it is cost effective and safe," Lyash said.

TVA has a staff that evaluates new nuclear technologies and the utility recently obtained regulatory approval for an early site permit to locate small modular reactors on the Clinch River in Oak Ridge.

"This is intended to maintain the option for TVA sometime in the future to build new nuclear, including small modular reactors," Lyash said. "Clearly, we haven't made a decision to go forward with that, but we think it is important that we maintain that as an option and monitor how the economy develops, what our load does, carbon regulations and other factors. We work closely with DOE in Oak Ridge and others on the technologies that go into that."

Contact Dave Flessner at dflessner@timesfreepress.com or at 757-6340.