North Carolina regulators will hold their expert witness hearing on Duke Energy Progress' proposed 17.7% rate hike on May 1. It's the first multiyear rate increase ever planned in the state. That will give the commission the opportunity to gather public input about the rate proposal. The other N.C. electric utility owned by Duke Energy Corp. (NYSE: DUK) is expected file a multiyear rate hike proposal early next year. That will make for a $325.8 million overall hike in charges to customers, raising its total base revenue to $3.8 billion. The second proposed hike would go in effect a year later, raising charges to customers by $150.8 million, for a 4.3% overall increase. The third proposed hike would come Oct. 1, 2025, raising $138.3 million more in a 4% overall increase. Duke Progress' base annual revenue would be almost $4.1 billion. By Oct. 1, 2025, Duke Progress estimates the average monthly bill for a typical residential customer would be 18.7% higher than it is now. That average increases to $151.98 per month from the current $126.43. The commission's Public Staff, which represents customer interests, and all other intervenors are to file their comments by March 27. Duke is to file its rebuttal to those comments by April 14. The expert witness hearing starts at 2 p.m. on May 1, the order says. Historically, final rates are lower than utilities in North Carolina seek. And there are some obvious areas where those rates are likely to be cut. The most obvious one is on Duke's request for a 10.2% return on equity be built into its rate. The utility now gets 9.6%, and the Public Staff and other intervenors are expected to argue Duke Progress does not need the large increase in the return it receives. The Public Staff and intervenors are also likely to argue against Duke's proposal for a capital structure made up of 53% equity and 47% debt. Its current structure is 52% equity and 48% debt.