For the first time in nearly 50 years, state-owned utility Santee Cooper generated less than 60 percent of its electricity from coal last year, according to the Moncks Corner-based company.

Not since 1966 has the utility produced less power from coal as a percentage of overall power sales, utility spokeswoman Mollie Gore said.

Historically, about 80 percent of Santee Cooper’s electricity came from coal, she said.

The low-cost of natural gas, which accounted for 30 percent of the utility’s power production, and the closing of four old coal-fired units in Moncks Corner and Conway at year’s end attributed to the decline, they said. Natural gas normally generated about 7 percent of power for the utility.

The low-cost of natural gas, which accounted for 30 percent of the utility’s power production, and the closing of four old coal-fired units in Moncks Corner and Conway at year’s end attributed to the decline, they said.

Two little-used, oil-fired units in Moncks Corner are also set to be retired, with no specific date announced.

When two new 1,100-megawatt nuclear units come online in 2017 and 2018 at the V.C. Summer Nuclear Station, which Santee Cooper jointly owns with South Carolina Electric & Gas Co. north of Columbia, the utility can rely on additional nuclear-generated power capacity with more flexibility to respond to volatile fuel markets, they said.

Reach Warren L. Wise at 937-5524 or twitter.com/warrenlancewise.