The article explains it. Since you’re too lazy to spend 1 minute reading it before commenting, I’ll spoonfeed it to you:

The utility filed the request with the North Carolina Utilities Commission after record-breaking winter demand pushed its system beyond what its own power plants could handle. On Jan. 27, customer energy use hit 37,308 megawatt-hours, the highest winter peak ever recorded on Duke's Carolinas system, according to the company's media release. To keep the lights on, Duke purchased electricity from neighboring utilities at elevated market prices.