The state Public Service Commission on Wednesday unanimously approved an agreement that will increase the power bills of Progress Energy Florida customers — who already pay among the highest rates in the state.

It is supposed to be a win for consumers.

The deal includes a $288 million "refund" of money customers were to pay to replace power from the crippled Crystal River nuclear plant, which has been offline since fall 2009 and might never return to service.

PSC staff concluded that customer rates still would increase. The average Progress customer's bill on Jan. 1 is expected to increase $4.93 a month per 1,000 kilowatt hours of usage, from $123.19 to $128.12, subject to adjustments for fuel costs.

But the Office of Public Counsel, which represents consumers before the PSC, said that without the agreement, rates could have increased twice as much next year and five times as much in five years.

The agreement also raised concerns among commissioners about the future of Progress' entire nuclear power program in Florida.

Though the Crystal River nuclear plant — which suffered cracks in its concrete reactor containment wall during a maintenance and upgrade project — was the focus of the agreement, consumer advocates and the utility also moved to settle other issues with Progress' proposed Levy County nuclear plant.

Part of the agreement limits the amount Progress can collect in advance for the Levy project for the next five years. That could hamstring Progress' efforts to build the $22.5 billion project.

"I still do have some concern about the Levy nuclear projects," said Commissioner Eduardo E. Balbis. "Any delays in this project could result in a reduction of the cost-effectiveness to the point where the projects are no longer viable."

Commissioner Julie Brown said she had "reservations" about the repair and replacement plan for Crystal River, but in the end was "persuaded that the agreement is in the public interest."

Ivan Penn can be reached at ipenn@tampabay.com or (727) 892-2332.