By Samuel Hardiman, Daniella Medina, Brittany Crocker

February 20, 2021 - While the "unprecedented" winter storm that continues to grip much of the U.S. and the Mid-South has left millions without power, Tennessee was able to avoid these extended outages and rolling blackouts.

Aaron Paul Melda, transmission and power supply senior vice president for the Tennessee Valley Authority, says the utility's continued reliability is a product of its dedicated workforce and its public power system model.

"We have been built and funded by the people of the United States and the Tennessee Valley and are beholden to them alone," he said, adding that the utility can plan its grid and operations more conservatively in the absence of investor pressure.  

"We work to balance cost and high reliability and ensure a diverse fleet so that we have the ability to shift power sources if need be," he said.

"We have an underlying philosophy of not putting all our eggs in one basket."

The TVA's power comes from coal, hydroelectric, natural gas, nuclear and renewable energy sources.

Forty percent of TVA's generating capacity is nuclear, and 45% of its power is coming from carbon-free sources, according to the company. According to Nuclear Regulatory Commission data, most of TVA's nuclear reactors operated at full capacity Monday and Tuesday.

TVA expected to hit peak demand for the week on Tuesday morning with an estimated 28,500 megawatts, but that morning it reached only about 28,141 megawatts, the company said. TVA had 36,000 megawatts of capacity in anticipation of the spike.

Melda said it would take temperatures of -10 across the Tennessee River valley for TVA to have to use all of its generations at once, and still, rolling blackouts would be unlikely unless a nuclear unit suddenly went offline.

Furthermore, TVA did not anticipate any power outages from the winter storm, according to a statement from a Memphis utility service.

“We have not been contacted by [the Tennessee Valley Authority] about any reliability issues and are not asking people to conserve or planning rolling brownouts,” Memphis, Light, Gas and Water said in a statement to the USA TODAY Network on Monday. TVA supplies MLGW with all its power and had enough capacity to meet the needs of its seven-state footprint.

Why Power Outages, Rolling Blackouts Occurred Across the Mid-South

In Texas, millions were without power Tuesday morning because the Electric Reliability Council of Texas lost a significant amount of capacity from the state's natural gas plants and some from frozen wind turbines. The plants relied on gas coming from the wellhead and gas production in Texas plummeted during the cold snap.

Entergy, which serves parts of Texas, Louisiana, Arkansas and Mississippi, also had outages due to a loss of electricity generation and equipment malfunctions in the extreme cold. The Midcontinent System Operator, the transmission system that Entergy belongs to, directed Entergy and its other members to conduct controlled outages to keep the electric system stable.  

"This is an unusual situation driven by extreme weather conditions much of the country is experiencing," said Kurt Castleberry, Entergy's Director of Resource Planning and Market Operations, to KATV in Little Rock, Arkansas. "We are working to respond and bring the electric system back to a normal operational state as soon as possible.”

Utility Systems' Weaknesses Exposed During 2021 Winter Storm

But how reliable are energy providers like Entergy after witnessing statewide blackouts?

The freezing cold weather and the current state of Entergy’s infrastructure caused the rolling blackouts, a Southern utility expert explained in an interview Tuesday.

Chip Estes, a Mississippi-based energy consultant who has worked for Midcontinent Independent System Operator and Entergy, said the extreme cold that descended on the Midwest and South exposed weaknesses in the utility systems that serve Texas and Arkansas, in particular.

"Without a doubt, it has highlighted the challenges that MISO has in keeping the lights on in the South," Estes said. "Entergy has a long way to catch-up, and, they're trying, to [catch-up] to the standards of assets in TVA and Southern Co."

Southern Company is a Georgia-based publicly traded utility that serves much of Georgia, Alabama and Florida.