On Thursday, North Carolina Attorney General Roy Cooper appealed a decision by the State Utilities Commission that approved Duke's roughly 7 percent rate hike.
This is the second time regulators have given Duke Energy a thumbs-up for the proposed increase. In 2011, Duke applied to raise rates by 15 percent.
After a public outcry, Duke Energy cut the proposed increase to roughly 7 percent and agreed to spend millions to help low-income customers pay their bills.
The 7 percent hike would allow Duke to increase revenues by $309 million.
Cooper appealed to the Supreme Court, which struck down the commission's approval of the rate hike, urging the board to take further steps to measure the impact on customers.
Now that the commission has again approved the hike, Cooper believes commissioners ignored the court's decision.
"We told the Utilities Commission that you can't just window dress, you've got to go in and measure directly how this affects consumers. They didn't do that," Cooper said.
However, Duke Energy said the rate hike will help the company modernize, build new plants and shutter older, less efficient ones.
Channel 9 received a statement from Duke Energy Thursday that says, in part: "Duke Energy believes that the N.C. Utilities Commission order is fair and appropriately balances the interests of both our customers and the company. Our rates remain below the national average."
Advocates for senior citizens and low-income families are saddened by the vote approving the rate hike.
"We don't think the energy company should be getting a rate increase on the backs of folks who are struggling right now," said Leo Scarpati, with AARP in Charlotte.
He said the advocacy group is concerned about seniors on fixed incomes and already dealing with soaring consumer prices.
"Seven dollars a month makes a big difference to seniors who are paying for prescription medications that are going up, food prices that are going up. That could be someone's meal for the day," he said.
Cooper said the issue for this appeal is that the rate increase means a double-digit profit margin for Duke, which he believes is too high, coupled with higher monthly bills for thousands of people.
"You've got a lot of working families and businesses out there who are struggling to meet a budget, and they don't need higher utility bills," Cooper said.
The attorney general's appeal, filed Wednesday, now goes back to the Supreme Court. It's not known when, or if, the court will hear the case again.
Duke customers across North Carolina have already been paying part of that increase on their monthly power bills since it was first approved in February 2012. If the commission does reverse its decision, customers could be entitled to refunds.