Utility companies issue pleas to conserve power, warn of rolling blackouts

Several major U.S. utility companies are asking customers to conserve electricity due to freezing temperatures over the weekend, while other companies warned they would impose rolling blackouts. 

On Saturday, Duke Energy, which services 8.2 million customers in six states, asked people to "reduce their energy use" through Christmas. Later that day, the company announced that it was "forced to interrupt service to about 500,000 customers in North and South Carolina to maintain the energy grid and prevent further disruptions" due to the cold weather causing an increased demand for power. 

Con Edison, which has 3.5 million electric customers, urged the public to set thermostats at the lowest comfortable temperature possible and use appliances only as needed.  

The electricity grid operator for 65 million people in 13 states, PJM Interconnection, called for the public to conserve electricity, especially from 4 a.m. on Saturday through 10 a.m. on Sunday. 

"It will do everything possible to keep power flowing in the region," said the company, while also warning: "If necessary, PJM may take additional steps, such as reducing voltage."

Winter Storm Elliott has brought frigid temperatures across the United States and left more than 1 million people without power on Christmas Eve. More than a dozen people have died from the storm so far.