TVA explains December’s rolling blackouts
Tennessee Valley Authority officials delved Tuesday into the factors that spurred the federal utility to order its first-ever rolling blackouts right before Christmas.
In a briefing for a Tennessee House subcommittee, the TVA representatives explained how multiple power plants failed at different points in the midst of a winter storm that sent temperatures plummeting into the single digits and energy demands soaring to record levels.
On Dec. 23, TVA ordered the 153 local power companies it supplies to start rolling blackouts to preserve the electric grid, sparking sharp criticism from customers and public officials across Tennessee and the parts of six surrounding states the utility serves.
Here are three findings TVA shared during its public presentation to lawmakers in Nashville.
TVA has made repairs to its system since the December storm
Kris Edmondson, TVA vice president of coal operations, addressed concerns raised by the Business and Utilities Subcommittee about the state of the electric grid. “”We feel very confident that that we have hardened the areas that we failed,” he said.
He explained that TVA brought in independent teams to visit sites and verify the effectiveness of the repairs.
“It’s hard to guarantee 100%, right, because when you’re dealing with a storm, you just don’t know what all you’re going to face,” Edmondson said, “but we feel like we have certainly taken action on every item that caused us issues before.”
TVA will have its review of the blackouts done early this year
TVA enlisted a panel of industry experts to join its review of the events that led to the rolling blackouts Dec. 23-24, and how the federal utility can learn from what happened.
Dan Pratt, TVA senior vice president of senior relations, told the subcommittee the utility also will consult with 10 local power companies, the Tennessee
Valley Public Power Association and a group of its energy-intensive industrial customers.
The review is planned to conclude at the end of March or in early April, Pratt said. He told the lawmakers TVA will be in a position then to dive even deeper into the causes of the rolling blackouts, as well as what it needs to do in the short and long term to avoid a reprise.
Critical instruments froze at coal and gas plants during the storm
TVA’S study of the rolling blackouts revealed one of the biggest breakdowns during the winter storm: sensing lines for critical instruments that are kept outside or not fully enclosed froze at some of its natural gas plants and its major coal plant.
In preparation for the storm, Edmondson said, TVA used wind breaks and tried to insulate and temporarily heat pieces of infrastructure to prevent failures.
“The majority of the megawatt loss events were due to sensing lines freezing up, critical instrumentation that froze up,” Edmondson said.
Lawmakers asked TVA what it planned to do to prevent a similar failure from happening again. Edmondson said TVA will consider permanently enclosing exposed equipment, though that’s not possible for every site because of their layouts. Windbreaks help, he said.
TVA also addressed whether older plants didn’t fare as well under the stress of the storm. Edmondson said at the Cumberland coal-fired plant, the exposed equipment was the problem. He acknowledged the age of the TVA gas plants likely was a factor.
Edmondson pointed out TVA purchased some of its gas facilities, and there are performance inconsistencies between those plants and ones commissioned by TVA. “We felt like that’s going to be a learning that we want to make sure we take action on,” he said.
Anila Yoganathan is a Knox News investigative reporter. You can contact her at anila.yoganathan@knoxnews.com, and follow her on Twitter @Anilayoganathan. Enjoy exclusive content and premium perks while supporting strong local journalism by subscribing at knoxnews.com/subscribe.