In her testimony with the state Utilities Commission, Rachel Elliott, director of rates and regulatory planning for Duke Energy Carolinas, said the company expected about 3% of the projected savings to come from corporate administrative costs, such as having to only file one rate case, saving on legal fees and other regulatory expenses.

Duke Energy Corp. says its move to combine electric utility subsidiaries in North and South Carolina into one entity could save customers more than $1 billion over a decade.

Michael Walden, a retired economics professor at N.C. State University, said the merger "should increase efficiencies, although at least some of the savings likely will come from eliminating some positions.