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A pair of environmental groups is challenging the Public Service Commission's decision to let South Carolina Electric & Gas charge customers $2.3 billion for its failed nuclear project. File/John A. Carlos II/Special to The Post and Courier

A pair of environmental groups will challenge state regulators’ decision to let Dominion Energy buy South Carolina Electric & Gas and charge ratepayers for its failed nuclear project.

The legal challenge means that regulators on the state’s Public Service Commission will have to formally reconsider their decision, which would leave SCE&G customers to pay $2.3 billion over the next two decades for a pair of abandoned nuclear reactors.

Regulators are unlikely to overturn their own decision, but the move sets the stage for an appeal to the state Supreme Court.

The process was set in motion Monday by Friends of the Earth and the Sierra Club, a pair of environmental groups that faced off against SCE&G throughout the decade-long nuclear project. They filed their protest with the commission — the same regulators who made the decision.

The environmental groups say the PSC should have officially made a determination about whether SCE&G handled the nuclear project appropriately. Attorneys opposing the power company argued SCE&G failed to tell regulators about studies that questioned the project’s viability.

The PSC chided SCE&G this month, saying it had damaged the public’s trust. But regulators stopped short of formally saying they had been misled.

The environmental groups went further. They argued Monday that “SCE&G fraudulently lied, misled and withheld material information” about the problems that sank its $9 billion plan to build a pair of reactors at V.C. Summer Nuclear Station, north of Columbia.

SCE&G and Dominion, a Virginia-based utility giant that has offered to buy it, couldn’t immediately be reached for comment Monday.

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It’s not clear whether the case will ultimately make its way to the Supreme Court, or whether it will affect Dominion’s plans to buy SCE&G. Regulators blessed the sale this month, when they decided to let SCE&G charge for part of the reactors.

The plan approved by the Public Service Commission would keep electricity rates about where they are now after the state Legislature ordered a temporary rate cut this summer. The nuclear project currently costs about $5 a month for the typical home using 1,000 killowatt-hours.

Reach Thad Moore at 843-937-5703. Follow him on Twitter @thadmoore.