Frozen equipment, record demand led to unprecedented rolling blackouts in Midlands

jholleman@thestate.comJanuary 7, 2014 

— SCE&G had to utilize emergency rolling blackouts early Tuesday because of a combination of near-record demand and power plants automatically knocked out of commission by frozen remote components.

The rolling blackouts, the first ever for SCE&G, left several schools, two hospitals and up to 51,000 customers without power, according to Keller Kissam, president for retail operations.

Many Midlands school districts started two hours late on Tuesday so students wouldn’t be waiting for buses at the depth of the cold, and many opted for delayed starts again Wednesday when temperatures were expected to drop into the teens. Shelters reported larger crowds than typical, but the frigid weather overall created few major problems in the Midlands. Two cold-related deaths were reported in the Upstate.

However, the record-breaking cold was the root cause of the rolling blackouts. Sensors on remote transmitters froze, leading to a serious of automatic reactions that shut down three of SCE&G’s 22 power stations. That forced SCE&G to institute rolling blackouts to handle the power demand without crashing the system.

“I want to apologize to parents,” Kissam said. “You sent your kids off to school this morning expecting them to be warm, and we let you down.”

The emergency protocol was designed to avoid cutting off power to essential buildings, but it never had been instituted. At least two hospitals — one in Aiken and one in Charleston – briefly lost power because of the rolling blackouts, but both had backup generators and power was quickly restored, Kissam said.

The rolling blackouts began around 7:30 a.m., when about 20,000 customers were without power. They escalated over time, peaking at 51,000 customers without power. Kissam said the rolling blackouts were finished before noon.

The biggest problem was in Saluda County, where nearly 3,000 people still did not have service by midday Tuesday.

Four separate outages affected more than 200 Santee Cooper customers in Horry County. Duke Energy said it had about 4,000 customers without service in western South Carolina. The biggest problem was in Oconee County.

Temperatures hit record lows throughout the state early Tuesday – 5 degrees at Greenville-Spartanburg, 13 at Columbia and 20 in downtown Charleston. Factoring in wind, Columbia’s airport had a wind chill of 1 degree at 3 a.m.

SCE&G’s power usage hit 4,854 megawatts as the blackouts began, just below the power company’s winter peak record of 4,866 megawatts set on Jan. 14, 2011. Demand likely will be high again Wednesday morning. SCE&G plans to use portable heaters, like those used by football teams in freezing stadiums, to ensure the remote transmitters don’t freeze again, Kissam said.

The rolling blackout system is designed to protect the power grid from overload. Ideally, various substations are out for 15 to 45 minutes, then the blackouts begin at other substations. Some SCE&G customers reported longer blackouts, but Kissam noted that there were some power outages unrelated to the rolling blackouts. Trees fell on some lines during the windy night, prompting more standard outages.

While Kissam said the rolling blackouts were preventable, building infrastructure “to cover every component is probably not a realistic expectation.” But he vowed that the lessons learned Tuesday would prevent the same situation with frozen remote components from happening again.

SCE&G has resorted to voltage reductions in the past to deal with record demand, but this was the first time the company had to go to rolling blackouts, Kissam said.

The Associated Press contributed to this report.

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