Duke Energy completed its acquisition of Piedmont Natural Gas, closing the transaction effective Oct. 4. Piedmont will retain its name and operate as a business unit of Duke Energy. Both companies are headquartered in Charlotte, N.C.

The acquisition will add Piedmont's 1 million natural gas customers to Duke Energy's customer base of 525,000 natural gas customers and 7.4 million electric customers.

Duke Energy will integrate Piedmont's corporate functions, including accounting, human resources and information technology, into its structure.

The North Carolina Utilities Commission approved the acquisition during the week of Sept. 26. This was the final regulatory ruling needed to complete the transaction, according to the Oct. 4 press release.

The Tennessee Regulatory Authority and Piedmont's shareholders previously approved the transaction, and the United States Federal Trade Commission has already granted early termination of the waiting period under the federal Hart-Scott-Rodino Antitrust Improvements Act.