COLUMBIA — South Carolina's utility regulators slashed a planned rate hike for Duke Energy's electric customers in the Upstate, calling the company "tone deaf" and chastising it for "excessively high" executive compensation.

The seven regulators on the Public Service Commission went after the plans of Duke Energy Carolinas with a hatchet, blocking the utility from collecting tens of millions of dollars.

Altogether, they eliminated 54 percent of the costs the energy giant wanted to pass along to its 591,000 customers from Greenville to Rock Hill. 

Those ratepayers showed up to several public hearings earlier this year voicing outrage over Duke's request. 

It's too early to say how much more the average Duke Energy customer will pay per month due to the decision. But it will be much less than the $14 per month the utility wanted to tack onto people's bills. 

Ryan Mosier, Duke Energy's spokesman, said the company disagrees with some of the commission's  findings and legal conclusions. He didn't say if it plans to appeal the decision to the South Carolina Supreme Court. 

"It is critical to balance the needs of our customers with smart investments that keep costs as low as possible and keep South Carolina competitive for the long term," Mosier said. 

Attorneys who have practiced in front of the commission for years believe the decision might signal a turning of the tides in South Carolina — a sign that utilities will face tougher scrutiny in the future. 

"The commissioners are not supposed to be passive, neutral observers. They should be aggressive regulators," said Bob Guild, an attorney representing the Sierra Club in the case. "If this is a new trend, it's a trend in the right direction."

Three of the seven regulators now on the commission were chosen by state lawmakers in the aftermath of the failed V.C. Summer nuclear project that left a $9 billion uncompleted financial fiasco behind.

Thomas Ervin, one of those new commissioners, authored the Duke Energy decision.

"The CEO and executive team demonstrated they were 'tone deaf,'" he wrote in the notable decision. 

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As part of their decision, commissioners also reduced the profit margins Duke Energy can collect in the future. That will save homes and businesses roughly $39.5 million per year, according to the Office of Regulatory Staff, the state's utility watchdog agency. 

The regulators also cut down on what the utility may charge ratepayers for the cleanup of millions of tons of coal ash in North Carolina. That change will save customers roughly $121 million that they would have otherwise paid in the coming years, according to ORS. 

The commission also took direct aim at the executive suite of Duke Energy. They stopped the company from charging ratepayers for a significant chunk of the compensation for Duke's top four executives, including CEO Lynn Good.

Good netted more than $21.4 million in 2017. 

The regulators did approve the company's request to charge $10.5 million per year for the Lee Nuclear Project near Gaffney that never got off the ground. But they rejected the company's request to collect another $9 million annually on top of that to cover the interest payments and profit margins on the would-be project. 

Nanette Edwards, the director of the Office of Regulatory Staff, believes the commissioners did a good job of balancing the utility's request with ratepayers' interests. 

The commission is expected to issue a separate decision for Duke Energy Progress — another utility that serves customers in the Pee Dee — in the coming weeks.  

Reach Andrew Brown at 843-708-1830 or follow him on Twitter @andy_ed_brown.