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Contributed photo by the Tennessee Valley Authority / TVA operates 16,300 miles of transmission lines to deliver power across its 7-state region, including the 161,000-volt line pictured here atop Raccoon Mountain overlooking downtown Chattanooga.

This story was updated Wednesday, Nov. 11, 2020, at 8:30 p.m. with more information.

The past year has been the best ever for keeping the lights on in the Tennessee Valley.

During fiscal 2020, the Tennessee Valley Authority cut its power outages and interruptions by more than 20% from the previous record year in 2018 to achieve the most reliable power delivery in the utility's 87-year history. On average, TVA delivered the electricity it generates during the past year with only 2.72 minutes of interruptions for the entire 12-month period, officials said Wednesday.

"We have had a positive trend in power reliability over the past couple of decades with over 25 years of delivering power with 99.999% reliability," said Aaron Melda, vice president of transmission operations and power supply for TVA. "This record is the result of years of work by everyone in transmission, with support and collaboration from many others from across the fleet."

Melda said power interruptions are only about 10% of what they were when TVA began closely monitoring such data in 1982. Over time, TVA has upgraded network monitoring and controls, improved transmission lines and limited vegetation around its facilities and the utility has begun to install over 2,700 miles of fiber optic lines to improve data and controls over how TVA power is dispatched and delivered.

To further improve its reliability, TVA is spending more than $300 million to build a new systems operations center in rural Meigs County and make other system upgrades as part of an upgrade that TVA officials have dubbed "Grid 2023." Despite initial opposition from neighboring residents, TVA has begun laying the foundation for the new facility on more than 150 acres near Gunstocker Creek in Georgetown to replace the power control center now located in the basement of TVA's downtown Chattanooga Office Complex.

As the largest government utility in America, TVA sells its wholesale power to 153 municipalities and power co-ops and 52 direct-served industrial customers across the Tennessee Valley delivered along 16,300 miles of high-voltage transmission lines.

Most of the nearly 10 million power users in the region get their electricity from local power companies such as EPB in Chattanooga, which are usually more subject to power outages and interruptions along electricity poles and lines that serve individual homes and businesses. For the typical electricity user in the Tennessee Valley, most power interruptions occur from their local power distributor.

Melda said TVA is among the top 10% of all U.S. utilities in the reliability of its power service and its local power companies rank among the top 30% of all utilities for reliability. EPB, which has installed a fiber optic network with intellirupters throughout its 600-square-mile area, is more reliable than most local power companies in the Valley which have yet to install such "smart grids."

"Since building Chattanooga's smart grid in 2012, we have been able to use the smart grid to quickly re-route power around many problems," EPB Vice President J. Ed. Marston said. "This has allowed us to reduce the frequency and duration of outages by about 50%."

In the 2019-2020 fiscal year, EPB estimates its smart grid helped avoid 60 million customer outage minutes. During the April tornadoes that temporarily cut power to nearly a third of all EPB customers, Marston said the smart grid allowed EPB to rapidly restore electricity service to more than 44,000 customers within minutes of the tornado touchdowns.

EPB and TVA employees are increasingly using smart grid technologies to detect potential power delivery problems before they happen by monitoring equipment, weather and power trends that could cause problems, Melda said. The smart grid also allows power to be rerouted and delivered in the most efficient manner when an outage occurs along a line.

"Over the last 10 years TVA has put plans in place to improve service to our customers, such as replacing high-risk assets before they failed, adding breakers and dispatcher-controlled switches to the grid, improving response plans and work execution," said Doug Bailey, vice president of transmission field operations for TVA.

Reliable power service is increasingly important for businesses that are using more robots, computers and other machines to perform tasks and need to operate without interruption.

"Our large, direct-served industrial customers are particularly impacted by a loss of power even for a short duration," said Mary Jane Owens, manager of TVA's direct serve accounts. "Outages stop production lines, shut down equipment operations and can impact safety."

The pandemic this year reduced overall electricity consumption for TVA, especially among some commercial and industrial customers, and TVA projects its power demand will remain relatively stable, or could even decline slightly, in future years as more energy-efficient machines are installed and distributed energy allows more consumers to generate their own power from solar panels, windmills and batteries.

Melda said TVA benefits by having a diverse power portfolio, including 29 power-generating dams that TVA can often use at maximum demand periods to help even its load.

Melda said TVA exceeded its stretch goal in fiscal 2020 for its power reliability and is trying to match or exceed that target in the next year.

Contact Dave Flessner at dflessner@timesfreepress.com or at 423-757-6340.

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