Duke Energy has over 4 million electric customers, its Commercial Power division has 8,700 MW of non-regulated generation capacity available, its international unit, Duke Energy International, has 4,200 MW of generation capacity.

• 1900: Catawba Power Company, located along the Catawba River, was the first power facility of what is now Duke Energy
• 1905: Tobacco tycoon and entrepreneur, James Buchanan Duke, invested in the holding entity, Southern Power Company, which later became Duke Energy
• 2005: Duke purchases Cinergy Corporation
• 2006: Duke Energy expands from the Southeast to the Midwestern part of the United States
• 2007: Duke establishes a gas business called, Spectra Energy