power lines

Power lines along Azalea Avenue in North Charleston. South Carolina's largest power companies are holding onto savings from the new federal tax law until regulators tell them how to divvy them up. File/Leroy Burnell/Staff

South Carolina's largest power companies say they're socking away the money they're saving from federal tax cuts — at least until state regulators tell them what to do with it.

The utilities, South Carolina Electric & Gas and Duke Energy, say they're calculating how much their tax bill dropped after President Donald Trump slashed corporate tax rates late last year. That's money ratepayers are entitled to, because taxes are baked into their power bills.

It's not clear when the Public Service Commission will hand down an order passing the savings onto electric users. But the state's top utility watchdog wants one soon.

The Office of Regulatory Staff, which keeps tabs on utilities in South Carolina, asked the commission Friday to put that process in motion. It wants utilities to lay out a plan for sharing their savings by the end of the month.

The new tax law impacts every investor-owned utility in the state — from SCE&G and Duke to a slew of smaller water companies — and it should save ratepayers at least a few dollars a month.

The exact savings, however, aren't yet clear. SCE&G has estimated that its rates will drop at least 3 percent, about $4.50 a month for the typical home. The Office of Regulatory Staff thinks they could fall as much as 5 percent, or about $7 a month. More detailed estimates are expected later this month.

SCE&G spokeswoman Rhonda O'Banion says the company is waiting for "an order from the Public Service Commission of South Carolina on how that benefit should be passed to customers" before passing the savings through.

Duke Energy, which sells power from the Pee Dee to the Upstate, hasn't released estimates of its savings. Spokesman Ryan Mosier says the company and regulators "agree that our customers will see savings and other benefits from the new tax law."

The tax law doesn't affect the state-owned power company Santee Cooper or the nonprofit electric cooperatives that it serves.

Similar processes are playing out across the country, and a handful of states have ordered refunds. Georgia Power, for one, says it's giving ratepayers $70 in refunds over the next few years. North Carolina and Kentucky have taken steps to make sure they're credited for tax savings going back to January.

Nanette Edwards, the director of the Office of Regulatory Staff, says her office wants utilities' plans in writing now so that they aren't fighting about big sums of money later. The agency aims to clear up the issue early, even if the savings aren't passed through right away.

"Time is of the essence," she says.

That's especially true in a state that's hyper-aware of its electric rates after SCE&G and Santee Cooper called off their $9 billion V.C. Summer nuclear project.

Regulators already need to decide how much ratepayers pay for the project, and Dominion Energy, which wants to buy SCE&G, has proposed to use the tax savings to help resolve that question. Dominion has suggested that the tax savings could offset part of the $27 a month the typical home pays each month for the project.

If the Public Service Commission waits until it takes up the Dominion proposal to handle the tax issue, though, it might be awhile until ratepayers' bills drop: Hearings on that plan aren't expected until November.

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