NOTICE OF FILING Application of Duke Energy Progress, LLC to Have the Terms of the Electric Rate Stabilization Adjustment (“eRSA”) Apply to the Company’s Rates and Charges for Retail Electric Service Docket No. 2026-78-E Why is this Notice Important? • On March 13, 2026, Duke Energy Progress, LLC (“DEP” or the “Company”), filed a Notice of Election of the application of the terms of the South Carolina Electric Rate Stabilization Adjustment (“eRSA”) mechanism to DEP’s rates and charges for retail electric service in South Carolina with the Public Service Commission of South Carolina (the “Commission”). • If the Commission’s Initial Order adjusts DEP’s rates charged to the Company’s customers, the rates will be effective as of the first billing cycle in August 2026. What is the Company asking the Commission to Approve? • Because DEP’s earned return on equity for the twelve-month-period ending December 31, 2025, was 7.81%, and DEP’s authorized return on equity is 9.99%, the Company requests that the Commission, in its Baseline Order, establish a range of return on equity under the eRSA mechanism of 9.49% to 10.49% (“ROE Range”). • The Company requests that the Commission approve an additional $36.625 million revenue required tobring its return on equity to the midpoint of the ROE Range. • The Company requests approval of the base rates set forth in its Annual Monitoring Report. What are Some Important Deadlines in this Case? DEADLINES June 1 Office of Regulatory Staff’s audit report filed with the Commission, utility, and parties June 1 Other Parties of Record’s verified written comments and documentary evidence filed in response to the utility’s monitoring report with the Commission, utility, and parties June 15 DEP files verified written comments and submits documentary evidence related to the utility’s monitoring report and may request a non-evidentiary hearing with the Commission and parties July 15 Commission issues its Initial Order setting forth any changes required in the utility’s request to adjust rates What are the Potential Bill Impacts for Customers? Typical Bill Impacts ($/month) by select rate schedules *Residential Commercial Industrial RES MGS LGS Typical Bill as of March 1, 2026 $163.07 $1,576.68 $53,526.50 Typical kWh Sales 1,000 14,000 650,000 Typical kW Sales 0 40 1,000 eRSA Change $10.20 $97.44 $1,759.50 Typical Bill with eRSA $173.27 $1,674.12 $55,286.00 Percentage Impact 6.25% 6.18% 3.29% *Residential rate is annualized The Company’s request in this proceeding arises under the eRSA, which is a statutory process that is separate from the Company’s general rate case proceedings. The case was filed according to S.C. Code Ann. Section 58-27-2760 and S.C. Code Ann. Section 58-27-2700 et seq. For the Company’s Proposal and for the Entire Case Visit: https://dms.psc.sc.gov/Web/Dockets/Detail/119659 Who Can I Talk to About This Notice? Duke Energy Progress, LLC 803-988-7132 Office of Regulatory Staff 803-737-5230 or 1-800-922-1531 Department of Consumer Affairs 803-734-4200 or 1-800-922-1594 Public Service Commission 803-896-5100 Ways to Get Involved in the Case How Can I Participate in this Case? A stakeholder may participate in the case by the ways listed below. Option A: File a completed Letter of Protest by: • Emailing the completed Letter of Protest to contact@psc.sc.gov; or • Mailing the completed Letter of Protest to 101 Executive Center Drive, Suite 100, Columbia, SC 29210. More information is available here: https://psc.sc.gov/consumer-info/file-letter-protest Option B: File a Petition to Intervene. An Intervenor becomes a party in the case. Intervenors have the right to testify, cross- examine witnesses, seek reconsideration of the Commission’s Final Decision, and must follow the Commission’s Rules of Practice and Procedure. To intervene, you must: • Email a Petition to Intervene to contact@psc.sc.gov no later than Friday, May 15, 2026; or • Mail a Petition to Intervene to 101 Executive Center Drive, Suite 100, Columbia, SC 29210 no later than Friday, May 15, 2026. Please include your email address. **You must give a copy of your Petition to Intervene to all Parties in this case. Petitions to Intervene must meet the requirements of Commission Regulation 103-825 and must be approved by the Commission. In the above referenced case, if the proposed tariffs contain any request for a change of rates, the proposed rates may be changed by the Commission. Persons seeking further information about these procedures should contact the Commission at 803-896-5100 or visit its website at www.psc.sc.gov Monday, March 23, 2026