Chattanooga homes and businesses had their electricity service interrupted Saturday with rolling blackouts for the first time in the 87-year history of EPB as temperatures continued in single digits for the second consecutive morning.
The Tennessee Valley Authority reached an all-time December peak power demand on Friday amid the coldest weather in eight years and for the first time ordered local power companies across its seven-state region to reduce their electric load to relieve stress on the power grid.
Although EPB avoided any forced power outages on Friday, the Chattanooga utility began interrupting electric service across its service territories Saturday for brief periods on a rotating basis for most of its 180,000 customers.
"This may necessitate brief power outages for EPB customers lasting about 15 minutes that may reoccur periodically," EPB spokesman J. Ed. Marston said in a statement Saturday. "We will do this in a controlled way to minimize the impact for customers as much as possible."
Some customers said they experienced outages lasting longer than 15 minutes.
"My house on North Shore lost power for several hours this morning," resident Malory Carberry said in an email to the Chattanooga Times Free Press. "Same with my parents in Hixson. We’re both EPB customers and were not warned until we went online to report our outage. Even then, the website said '15 minute' rolling blackouts, not hours-long blackouts. No huge impact to us, but would have liked to have been warned. They have our emails and phone numbers, so a mass notification would have been nice."
Missionary Ridge homeowner Thyra DeCicco said she and her neighbors along South Crest Road were without power Saturday for nearly six hours.
"There was no wind or bad weather, but we just woke up to this outage that began around 6:30 a.m. and lasted until about 12:30," she said in a telephone interview Saturday. "It was infuriating that on Christmas Eve when it was only about 5 degrees outside that we were out of power for so long and no one could tell us what happened."
When DeCicco called EPB about the outage, she had to wait for more than an hour on the phone and never got much of an answer about why some homes were in the dark for so long.
"You worry about frozen pipes and other problems just trying to keep warm," she said, explaining that her home temperatures dropped to about 60 degrees. "Thankfully, the power came back on when it did."
By midday, EPB and TVA said no further rolling blackouts would be needed.
Asked about reports of outages lasting longer than 15 minutes, EPB public relations specialist Sophie Moore said, "Although brief planned outages are not occurring at this time, several customers may be experiencing electrical outages due to damage caused by this weekend’s arctic blast. We are tracking those via our Smart Grid and repairing them as quickly as possible. We also encourage anyone experiencing an outage any time to let us know."
TVA first ordered power reductions of 5% from all of its 153 local power companies Friday morning, and EPB was able to achieve those power reductions Friday by voluntary cutbacks in power use by major customers to avoid rolling blackouts Friday. TVA ordered even more cutbacks Saturday morning, which Marston said EPB was unable to achieve without temporarily cutting power to some customers.
"We are hoping this event will only be necessary through the early morning hours when power demand is expected to be the highest, but we will continue to monitor this record-breaking event," TVA spokesman Jim Hopson said in a statement early Saturday.
Temperatures in Chattanooga dropped Friday morning to 7 degrees, and the low temperature Saturday at Chattanooga's airport was 8 degrees, according to the National Weather Service.
"We're on a warming trend, but it may stay below freezing in Chattanooga until Monday," Nathan Wellington, a meteorologist with the National Weather Service in Morristown, said in a telephone interview Saturday.
Sunday's high temperature in Chattanooga is forecast to reach 32 degrees; Monday's high is predicted to reach 36 degrees, and temperatures Tuesday are forecast to top out at 43 degrees, Wellington said.
With most homes and businesses heated with electricity in the Tennessee Valley, the cold weather created a surge in power demand Friday and Saturday as electric heaters and furnaces sought to keep up with the higher demand from what the National Weather Service called "a once-in-a-generation" winter storm.
High winds and cold temperatures combined Friday to push the windchill index, which measures how cold it feels, to minus 11 degrees in Chattanooga on Friday.
TVA's power demand topped 33,000 megawatts on Friday, or nearly 35% above the typical daily demand in December. The arctic cold wave boosted power demand for TVA to one of the highest winter levels, although Friday's peak was still below TVA's all-time highest power demand of 33,482 megawatts reached during a summer heatwave on Aug. 16, 2007.
"We continue to work to actively manage the impact of severe weather conditions, but these are unprecedented conditions," TVA Chief Operating Officer Don Moul said in an interview Friday. "We are working with our local power companies to take these proactive steps to ensure that the power grid remains stable."
High winds along with the cold temperatures from the arctic blast across much of the country created equipment problems at TVA's biggest coal plant and limited power from some natural gas-powered combustion turbines. At one point Friday, TVA lost more than 6,000 megawatts of power generation or nearly 20% of its load at the time, with both units at TVA's Cumberland Fossil Plant offline and other problems at some gas generating units.
In response, TVA activated its highest level of emergency load curtailment for a couple of hours on Friday and again on Saturday morning. TVA, which says it has maintained 99.999% reliable power delivery for more than 20 years, has never previously had to use rolling blackouts for its customers.
Moul said TVA is working to boost its generation and power purchases but is also asking electric users in the Tennessee Valley to reduce their power consumption wherever possible.
To help reduce energy consumption and prepare for rolling blackouts, EPB suggests:
-- Keep your thermostat at a normal setting or reduce by 1-2 degrees if you can do so safely.
-- Be sure to keep your thermostat setting consistent during any brief interruptions. Cranking up your HVAC can cause further problems.
-- Avoid using clothes washers, dryers, dishwashers and other major appliances.
-- Keep doors and windows closed as much as possible.
-- Keep your phone fully charged and ready at hand.
-- Gather flashlights and other supplies you may need.