Large data centers that want power from Santee Cooper will have to commit for at least 15 years and pay for their own grid connections under a rate the state-owned utility’s board made permanent Oct. 30.

The new High Impact Load rate replaces the experimental large load rate the Moncks Corner-based utility adopted in April 2025. The rate “requires high load customers, including data centers, to pay for incremental costs to serve them and sign a 15-year service agreement that includes financial guarantees,” Santee Cooper said in announcing the vote.

The board approved the rate along with new retail rates for 2027 and 2028. It applies to bills rendered on or after Feb. 1, 2027, according to the utility.

Who it covers

The permanent rate applies to data centers with a monthly maximum demand of more than 20,000 kilowatts, or 20 megawatts, according to the final 2027 rate schedules Santee Cooper posted on its website. The experimental rate applied to customers needing 50 megawatts or more, the SC Daily Gazette reported when the board adopted it.

Cryptocurrency mining and other portable computing operations of more than 1,000 kilowatts are covered, too. So are other facilities above 20,000 kilowatts with high load factors that don’t qualify for an economic development rate, the schedule says.

The rate is mandatory for Santee Cooper’s own customers that fit those descriptions. Electric cooperatives and towns that buy wholesale power from Santee Cooper may offer it to their own industrial and governmental customers, according to the schedule.

What a data center has to sign up for

The schedule sets out the terms:

  • A first contract of at least 180 months, or 15 years.
  • Payment in full for the cost of the delivery point and transmission work, including interconnection and network upgrades, before Santee Cooper builds or buys anything to serve the customer.
  • Collateral equal to 180 months of minimum bills, with at least 12 months of it as a cash deposit. Customers with credit ratings of A3 or A- or better can generally cover the rest with a guaranty, though Santee Cooper can reduce that allowance. Customers rated lower, or with no rating, must post the rest as a letter of credit or cash.
  • No reduction in contracted demand can take effect during the first 15 years of service, and later cuts are phased in over several years.

If revenue from these customers falls short of covering the costs they add, Santee Cooper can assess a separate “retail sufficiency recovery charge,” the schedule says.

Before fuel and other adjustments, the 2027 schedule’s base charges include $23.23 a kilowatt for monthly demand above the first 300 kilowatts and 4.97 cents a kilowatt-hour for on-peak energy.

Why the utility says it needs the rule

When the board adopted the experimental rate in April 2025, Mike Smith, Santee Cooper’s director of billing and pricing, said large customers coming into its territory could need as much as 1,000 megawatts of power as soon as 2030, the SC Daily Gazette reported.

“We do welcome large loads because they’re good loads for the system. However, because of their size and operating characteristics, they’re difficult for Santee Cooper to absorb,” Smith said then, according to the Gazette.

Customers raised the issue during this year’s rate review. “So you can see 23 customers identified data centers as a concern, that they did not want to be picking up the costs associated with those,” Greg McCormack, Santee Cooper’s senior director of financial planning, told the board Aug. 31, according to the meeting transcript.

At the same meeting, Jonathan Byrd of Concentric Energy Advisors, the board’s independent rate consultant, said Santee Cooper has “a very robust high impact load tariff” for its largest customers.

“We appreciate the time customers took to share their concerns and ideas throughout this process, and we used that feedback in finalizing the rates,” Santee Cooper President and CEO Jimmy Staton said in the utility’s announcement.