Duke Energy leaders will face questions from the N.C. Utilities Commission next week over the company’s decision to use rolling blackouts on Christmas Eve that affected about one in 10 customers in the Carolinas.
Sam Watson, general counsel to the Utilities Commission, said Duke will provide a briefing on the situation during a staff conference on 10 a.m. Tuesday. The proceedings will be open to the public and streamed through the commission’s YouTube channel.
The commission held a similar hearing following the electric substation attacks that left Moore County without power for days in December. Gov. Roy Cooper has also voiced concern about the use of rolling blackouts, saying he’s “asked Duke for a complete report on what went wrong and for changes to be made.”
We had questions too after reading news coverage over the weekend about Duke’s reasons for the outages. Here’s what we asked and what Duke Energy spokesman Bill Norton told us:
Duke spokespersons mentioned that one factor creating the need for rolling blackouts was a loss of generation. Can you provide any details on what power generation facilities were offline, why they were off, and for how long?
“We had to conduct temporary outages due to the combination of temperatures that were lower than forecast, customer usage that was higher than projected, and challenges at some of our generating units – we are reviewing those issues now and will be sharing details with regulators. On top of that, we had limited options for additional capacity from outside of our service area due to extreme cold weather that impacted the eastern half of the United States. We made this difficult decision to protect the electric grid and reliability on our system, and to avoid a potential longer or broader outage to customers.”
How many customers over the course of the weekend were affected by rolling blackouts, and what percentage of North Carolina customers were affected?
“About 500,000 customers in the Carolinas were impacted by the temporary interruptions of service during the day on Dec. 24, and those customers were restored around 6 p.m. that same day – most much earlier than that. We have about 4.5 million customers in the Carolinas, so approximately 11% of our customers were impacted that day.”
How were locations selected for the rolling blackouts? Was Duke able to avoid blackouts in areas of Moore County affected by the substation attack earlier this month?
“Our system determines where power is needed and where available capacity can be obtained through the use of targeted, temporary outages. The process is automated and conducted to protect the larger system reliability and all customers we serve from a potentially longer or larger outage.”
What were the minimum and maximum time of outage that customers experienced in the rolling blackouts?
“Outages varied in length based on system conditions and when they occurred. It also took a few hours to methodically restore customers once system conditions improved. System operations worked throughout the day to restore customers in ways that protected customer and overall system reliability.”
Will this weekend’s experience prompt a need for regulatory changes to prevent future similar situations? Is Duke considering adding any new power generating facilities to address periods of high demand?
“We will continue to keep our regulators and leaders informed on our operations and what we learn from this event. We work every day to improve our operations and get better – we will thoroughly review these events for lessons learned that can help us better serve customers now and in the future.”
I’ve seen speculation that Duke’s shift toward more renewable energy sources could be a factor in the weekend power shortage. Can you address whether that’s true or not?
“Solar is part of our diverse energy mix that provides the best resources available throughout the day to meet customer demand. Unfortunately, we began reaching our peak demand for electricity on Dec. 24 before the sun came up, so solar was not available to help meet customer needs at that time. It did contribute during the day as weather conditions allowed. We rely on a diverse energy mix to serve customers during extreme weather and high demand for electricity – renewable energy along with nuclear, natural gas, coal and hydroelectricity all play a part in that mix. We will continue working to improve our operations and the electric grid to make it more resilient and to better serve customers throughout the year.”