Duke Energy Carolinas (formerly Duke Power) energizes the Carolinas as well as its parent company's sales. A part of top US power firm Duke Energy, the regulated utility provides electricity services to about 2.5 million customers in North and South Carolina. Operating in a 24,000-square mile service territory, Duke Energy Carolinas has 101,400 miles of distribution cable. Its transmission system spans 13,100 miles. The utility has a net generating capacity of about 21,500 MW from interests in fossil-fueled, nuclear, and hydroelectric power plants. Duke Energy Carolinas also sells power to wholesale customers.