Duke Energy apologizes for holiday blackouts

Duke Energy officials apologized Tuesday for a series of outages on Christmas Eve that affected approximately half a million customers.

Company officials say some of the outages were longer than expected because of a failure of automation that required crews to restore the power manually.

At a briefing with the North Carolina Utilities Commission, Julie Janson, executive vice president and CEO for Duke Energy Carolinas, said the company owns what happened.

”We regret not being able to provide customers as much advanced notice of the outages as we would have liked," she said. "And we acknowledge that the outages themselves lasted far longer than we expected.” 

Company officials say the blackouts — unprecedented for the utility in the Carolinas — were the result of factors that included extremely low temperatures as an arctic front moved into the region, stronger than expected energy demand, and a loss of energy that the company purchased but was not available when expected.

Power generation at three North Carolina plants — coal-fired Mayo and Roxboro and natural gas-powered Dan River — were essentially cut in half early Dec. 24 when insulated instrumentation lines froze, Duke executives said. Meanwhile, already contracted purchases of electric power on a regional transmission system didn't happen because neighboring utilities had no supplies to share.

Faced with the threat of uncontrolled demand outpacing supplies and leading to widespread outages within the Eastern U.S., Holeman said the two subsidiaries began “load-shedding” events — rolling outages — beginning shortly after 6 a.m.

"We will strive to lower the probability that this type of event happens again, but if we have similar conditions in similar operating environments in the future, our operators will take the same actions,” he said.

The rolling outages are supposed to be automated and last only 15 to 30 minutes. But the automation tools didn't work as anticipated, according to a presentation, forcing the utility's distribution control center to shut down hundreds of circuits manually. All of the circuits were restored by around 4 p.m.

Duke executives said communicating this event to customers fell short, especially as it became clear that rolling outages would extend beyond 30 or even 60 minutes.

“We’re committed to developing a much better understanding of these events and what we can do to avoid rolling service disruptions and improve communications in the future,” Duke Energy State President Kendal Bowman said.

The seven-member commission, nominated by Democratic Gov. Roy Cooper, asked many questions and sought more information but largely avoided blame for what happened. Cooper tweeted last week that he was “deeply concerned” about people who didn't get notice about the rolling outages and asked Duke “for a complete report on what went wrong and for changes to be made.” The Federal Energy Regulatory Commission is also looking into what happened.

State utilities Commissioner Floyd McKissick said Duke's customer notification system needs to be upgraded as soon as possible so people who could be harmed by the loss of power — such as the elderly or those with medical needs — can be prepared.

“The only thing customers want to know is that power is there when it’s needed,” he said.

McKissick also cited the utility's power demand modeling, which Duke executives acknowledged was based on data from past weather events that didn't account for the unique confluence of circumstances last month. They included what Holeman called the lowest December temperatures since the 1980s, low dew temperatures, and wind chills, all during a holiday weekend.

The briefing came just four days after the commission issued a separate order detailing actions that Duke Energy must or should take to meet a new legislative mandate to reduce carbon dioxide emissions 70% by 2030 compared with 2005 levels.

Duke customers aren’t the only ones in the Carolinas dealing with energy issues this winter. Blue Ridge Energy, a not-for-profit electric cooperative with customers in the High Country, says rising costs will lead to a temporary 9$ per 1000-kilowatt-hour cost adjustment.