State regulators say that Florida Power & Light should have received $117 million instead of the $75 million base rate hike approved in January.
The Public Service Commission rejected most of FPL's record $1.27 billion rate hike request. But FPL said there were calculation errors that, if corrected, would have made the rate hike larger.
The commission staff said in a report Thursday that some errors were made and FPL should have received nearly $42 million more.
Both the commission staff and FPL recommend offsetting any additional increase with some of the $895 million the utility had collected to pay for power plants and equipment ahead of schedule. As part of its decision in January, the PSC ordered FPL to refund customers the money in four years.
But using that money to offset an increase could have consequences for consumers down the line, "potentially resulting in a larger base rate increase in the future," the staff report said.
The staff said it agrees with consumer advocates that FPL did not prove there was a $129 million discrepancy in other costs.
The commission is scheduled to vote on Aug. 3.
FPL spokesman Mark Bubriski said the utility does not want a rate increase: "We strongly recommend that the commission address the issues without changing customer rates."
He said FPL hasn't calculated how much a typical customer's monthly bill would increase if the PSC voted to increase base rates instead of using the reserve surplus but "but if you use the fact that the PSC's approved increase of $75.5 million added about a dollar, it's clear that FPL's typical monthly bill will remain the lowest of the state's 55 utilities."
It's unclear if FPL will agree to a deal similar to the one struck in May with Progress Energy Florida. Consumer advocates, the Attorney General's Office and business groups that represent large utility customers reached an agreement with Progress to freeze its base rates through 2012.
If a deal is struck with FPL and the commission approves it, some of the unresolved issues about the base rate hike could be moot.
Julie Patel can be reached at 954-356-4667 and jpatel@SunSentinel.com.