A new study says SCANA Corp. and Santee Cooper would save ratepayers almost $10 billion over 40 years by scrapping the two nuclear reactors they’re building and developing natural gas plants instead.

The report, “Public Risk, Private Profit, Ratepayer Cost, Utility Imprudence,” was released today by the Vermont Law School Institute for Energy and the Environment.

“The best estimate of the excess costs that will be borne by South Carolina ratepayers and the South Carolina economy is in the range of $10 billion,” the institute said in statement.

Mark Cooper, an analyst who worked on the study, said the economic underpinnings for the Fairfield County project has been weakened since regulators approved the expansion in 2009 by $283 million in new construction costs, flat demand and a 73 percent drop in natural gas prices.

The report said reactor projects in Florida and Georgia also should be abandoned.

“The economics of these new nuclear reactor projects could not be more abysmal for ratepayers,” Cooper said in a statement.

Bloomberg News reported that the utilities involved have little incentive to halt the expansions because ratepayers are funding the deals, not investors, Cooper said. South Carolina, Florida and Georgia allow power companies to charge customers for building costs as they are incurred, Bloomberg said.

The $10 billion Midlands project has triggered a flurry of rate hikes in South Carolina. The first of the two new reactors at the V.C. Summer Nuclear Station in Jenkinsville is scheduled to start generating power in 2017. The second will follow in 2018.

The Post and Courier is seeking reaction to the report from SCANA, which owns South Carolina Electric & Gas Co., and Moncks Corner-based Santee Cooper. They own V.C. Summer under a joint venture.