KYLE MURPHYStaff Writer

It has been a year since the “once in a generation” winter storm made its way to Middle Tennessee, causing the Tennessee Valley Authority to put out the call to all utilities, including Tullahoma Utilities Authority, to help reduce power at the generating plants by issuing temporary rolling blackouts. One year later, TVA officials said they have made the necessary changes to avoid that same scenario.

During Dec. 22 and 27, the winter storm, unofficially called Winter Storm Elliott by the Weather Channel, made its way to Tennessee from the Midwest, bringing freezing temperatures. According to TVA spokesperson Scott Fiedler, TVA had been monitoring the storm and started prepping the locations and facilities so they will be ready. However, what TVA didn’t anticipate was the speed and veracity of the storm.

“Winter Storm Elliott was once in a generation,” Fiedler said. “You saw bitter, cold temperatures from the Great Lakes to the Gulf, and from the Rockies to the Atlantic. That put a strain not only on TVA but on other utilities east of the Rockies.”

Fiedler said on the morning Dec. 23, 2022, the TVA Cumberland plant went down during the storm, due to the winter storm exceeded design specifications, causing icing and equipment freezing. Because of this, and other plants going down due to the freezing conditions, TVA instructed its 153 local power companies to curtail the power with rolling customer blackouts.

“TVA orders it, Tullahoma [Utilities Authority] complies and the other companies comply,” Fiedler said.

According to TUA President Brian Skelton, TUA has a power supply contract with TVA and for years had an Emergency Load Curtailment Plan (ELCP), which has steps where TUA would voluntary ask customers to adjust their thermostats to support the power supply. When TUA received the instruction to curtail power from TUA, they followed their ELCP plan and rolled customer outages on its 12 circuits, except for customers on the hospital circuit, saw a 15 minute outage for the two days. The rolling customer outages did not last too long on that Friday and Saturday, as the rolling outage call ended no later than noon on both days. Other power companies in the area, including Duck River Electric, Winchester Utility System, Shelbyville Power Water & Sewerage System and so on, issued similar statements from TVA to their customers and followed suit.

Skelton said the reason TUA decided to not take the hospital circuit offline during the rolling blackouts was due to the chance of the backup generator failing in the few hour window of the outages due to the cold temperatures. He said if the rolling outage had a 24-hour outage window then they would have taken that circuit offline as well. Skelton and Fiedler said this was the first time in 90 years that TVA had to curtail the load.

Fiedler said the reason why this was important to do was because it insured the integrity of the electric system, where it was overtaxed and failed.

“The processes worked and it made sure that the grid is stable and reliable and can be brought back up with minimal people affected at once,” Fiedler said. “It’s about minimizing the impact to the customer while insuring the grid’s stability.”

Since the winter storm, Fiedler said TVA had completed a top and bottom after action report on what happened, why it happened and how TVA could mitigate it. TVA then had an outside board, including former U.S. Senator Bob Corker and other industry experts, look at the report and agreed that actions TVA needed to take were in the report and TVA was moving forward. Since the spring, TVA began working on 334 items across its system, which includes investing about $123 million in reliability in FY23 and will invest another $120 million moving forward.

“Some of the items on the punch list include adding structures around critical equipment and sensors, keeping the heat in, adding addition heat tape around critical components to it warm, adding sensors that not only show visually that the heat tape is working, but also provide temperature back to the control room so equipment operators can monitor that and take action before something becomes a problem,” Fiedler said.

Other actions TVA has taken include taking the summer conducting strategies on how they would respond in plausible scenarios that could happen.

“We believe are much better prepared this year and beyond for any Elliott style storms. Our plan is to get it down to the NERC (North American Electric Reliability Corporation) and FERC (Federal Energy Regulatory Commission) standards of minus 20 degrees for 48 hours with 20 mph wind,” Fiedler said. “That’s what our plants should be able to withstand and that’s what we’re moving towards now.”

Skelton said he feels TUA is well prepared for a similar situation locally, with the utility authority having a transformation capacity of 200 MW, with the peak load during the winter storm was 72 MW, giving plenty of capacity to use if part of a circuit or one of its three substation goes offline.  

While TVA has spent the year making the necessary changes for their plants and equipment to be able to without extreme cold weather conditions, residents can still take a few steps to keep their home warm during the holidays and the rest of winter. Some of the simply solutions residents can do to keep the cold air outside include caulking windows and doors, seal gaps of doors with weather strips, open curtains on the south side of the house to let the natural heat in and keep thermostats at a level that is comfortable for them. Fiedler and Skelton added if customers can lower the setting a bit, they could save about 3% on their energy bill per every degree lowered. 

TVA also has a rebate program if customers have parts in need of replacement. For more information about the rebates, visit energyright.com.