Last November, Florida's Public Service Commission approved a $246 million annual rate hike for Florida Power & Light. The hike started hitting bills in January.
But now, Florida's consumer advocate is asking the Florida Supreme Court to overturn the rate hike.
At the time of the approval, the costs were supposedly linked with expanding two nuclear power plants in St. Lucie and Turkey Point.
Back in September, the Southern Alliance for Clean Energy challenged the rate hike, calling it a "nuclear tax'" for reactors that would very likely never be built or fixed.
See also: FPL Bills to Increase Come January
FPL disputed those claims, saying the reactor upgrades at the plants in St. Lucie and Turkey Point would be completed by the end of 2012. The upgrades were finished, but not until April of this year.
FPL also said that nuclear power saves everyone money in the long run because of low fuel expenses.
But on Thursday, lawyers for the consumer advocate argued that the tax rate is not a good deal for most of FPL's 4.6 million customers.
The Justices also heard arguments on whether regulators should have approved the increase in the first place.
The advocate group's argument is that the rate hike was approved because it was the result of a settlement where the Office of Public Counsel did not participate.
However, groups representing commercial and federal government customers were a part of the settlement, and agreed to the increase.
Should the rate hike remain, it could add charges to monthly FPL bills for the next three years.