North Carolina utilities regulators have approved the merger of Duke Energy and Progress Energy, the last major hurdle to creating the largest American electric company. North Carolina Utilities Commission Chairman Edward Finley Jr. said Friday the deal was the best possible in an environment of energy industry consolidation. Finley says it was preferable for the two North Carolina-based companies to combine rather than be bought up by a company elsewhere. Conditions to the merger include the companies passing along at least $650 million in savings to customers. The combined company will serve about 3 million customers in North Carolina and 4 million more in Kentucky, Ohio, Indiana, Florida and South Carolina.