SCANA headquarters (copy) (copy)

SCANA's corporate headquarters in Cayce. File/Andrew Brown/Staff

The biggest business decision in South Carolina’s history will be made exactly one year after the decision that caused it.

It’s a proposal that affects hundreds of thousands of families and businesses from Charleston to Columbia — everyone who buys electricity or gas from South Carolina Electric & Gas.

Investors in SCE&G’s owner, SCANA Corp., get their final say Tuesday on whether South Carolina’s biggest company should be sold. And for the first time since the company's nuclear project was scuttled last year, individual shareholders will get to ask questions of top executives.

If the deal goes through, SCANA will make up a fraction of a much larger energy conglomerate, Virginia-based Dominion Energy.

If it doesn’t, SCANA will be back to square one, dealing with a firestorm from its failed nuclear project.

Its abandoned plans to expand the V.C. Summer power plant currently cost ratepayers $37 million a month, nearly a fifth of their bills. Whether or not the deal is finalized, electricity users will be paying for decades — a half-century under SCANA or 20 years under Dominion.

The V.C. Summer project was called off one year earlier, on July 31, 2017. For a moment, it seemed like the finale of the nuclear project’s saga, capping years of delays and budget overruns caused by construction problems and unfinished designs.

It turned out to be the opening act of a profoundly complicated — and messy — debacle that is still playing out, one that hits the wallets of every SCE&G ratepayer.

It set off a series of lawsuits seeking refunds for the roughly $2 billion customers have already put into the project. It set off a legislative debate that ultimately cut electric bills temporarily. And it will lead to the biggest case that utility regulators have heard in modern South Carolina history, one that will set the final resolution of the V.C. Summer question — until it’s inevitably challenged in court.

Dominion has offered to short-circuit the messy process of finding a solution. It offered to buy SCANA outright, refund most of the money ratepayers have been charged and cut part of the nuclear project’s costs out of SCE&G’s electricity rates.

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The transaction was initially worth $14.6 billion, including SCANA’s debt, but its value varies day-to-day because SCANA shareholders will only receive Dominion stock.

The deal is almost certainly the largest in South Carolina history.

Shareholders will get their say Tuesday, and two-thirds of them have to vote for the deal to keep it alive. Even if they approve it, however, the tie-up still needs the blessing of state regulators.

That will be the biggest test for the SCANA sale. The Public Service Commission, which regulates utilities, will hold hearings on the Dominion plan starting in November.

Before they start, regulators will hear from ratepayers, too, giving SCE&G customers one of their first opportunities to have a say on the nuclear fiasco in an official setting.

The commission is expected to hold hearings in early October in Columbia, but it’s possible more could be held. The Office of Regulatory Staff, a watchdog agency, has asked for meetings to be held closer to other SCE&G customers, such as Aiken and Charleston.

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