Rainey Generating Station Expansion Announced to Meet Growing Energy Demand
In a strategic move to enhance efficiency and meet growing energy demands, Santee Cooper is undertaking a $470 million expansion of its Rainey Generating Station (RGS) as a Shared Resource with Central Electric Power Cooperative Inc.
The expansion includes taking two GE 7FA.03 simple-cycle units designated Units 2A and 2B and converting them into a combined cycle unit.
The combined-cycle conversion project involves installing two heat-recovery steam generators, a steam turbine generator, a steam surface condenser, and a wet mechanical draft cooling tower and associated components. These upgrades will capture the waste heat from the two existing simple-cycle units and use that heat to generate nearly 200 megawatts (MW) of additional electricity – with no increase in the emissions rate and without having to build an additional generating station.
Simple-cycle units operate by using combustion turbines to generate electricity, but they do not utilize the waste heat produced in the process. By transitioning to a combined-cycle configuration, the facility will now capture and repurpose this excess heat to power a steam turbine, generating additional electricity without more fuel. This approach boosts overall efficiency and supports modern energy sustainability goals.
"This combined-cycle conversion project will play a vital role in ensuring reliable power for our growing population,” said Jimmy Staton, president and CEO. “By utilizing an existing site, it adds much-needed capacity without increasing fuel costs or emissions rates, aligning with our commitment to affordability, sustainability and efficiency."
The expansion and additional capacity to the grid will support both retail and industrial energy needs. Additionally, the upgrade will contribute to grid stability and provide greater operational flexibility, particularly during peak demand periods.
RGS was originally designed with future expansion in mind. The generating station commenced commercial operation in January 2002 with a 500 MW combined-cycle unit. By May of that year, two 150 MW simple-cycle combustion turbines were also brought online. The layout of the station was strategically planned to facilitate expansion without requiring major modifications. Adequate space was allocated for the steam turbine, the expansion of the steam building, and the installation of a heat recovery steam generator (HRSG) behind the two gas turbines, along with a cooling tower. Additionally, the switchyard, electrical infrastructure, and control systems were all designed to accommodate future growth seamlessly.
Central Electric Power Cooperative Inc. is Santee Cooper’s largest customer. Central’s President and CEO Rob Hochstetler, who heads the utility supplying power to the state’s electric cooperatives, noted the importance of South Carolina power providers bringing additional generation resources online.
“This project illustrates how Santee Cooper and South Carolina’s electric cooperatives are working collaboratively to meet our state’s growing energy needs,” said Hochstetler. “Our staff and board studied this project at length, and we agree with Santee Cooper’s conclusion that expanding the Rainey Generating Station is a smart, cost-effective and environmentally responsible way to expand a key source of reliable energy.”
The project is expected to be complete by the end of 2027. The project will create seven full-time positions, as well as approximately 300 temporary jobs during construction.
Key Dates
- Aug. 27, 2024: Santee Cooper Board of Directors adopted a resolution authorizing a S.C. Public Service Commission (PSC) filing under the Siting Act for a Certificate of Environmental Compatibility and Public Convenience and Necessity (CECPCN) that would allow the Authority to proceed with the project once the CECPCN is obtained.
- Sept. 16, 2024: PSC Docket No. 2024-264-E, the Authority filed the application under the Siting Act to construct and operate the project.
- Oct. 28, 2024: The JPC approved the project as a proposed Shared Resource under the Coordination Agreement between Santee Cooper and Central.
- Dec. 11, 2024: Central’s Board of Directors approved the project as a Shared Resource.
- Dec. 20, 2024: Santee Cooper Board of Directors approved the Rainey Generating Station expansion.
Bids for the HRSG, steam turbine generator (STG), and generator step-up transformer (GSU) went out in 2024, and were awarded in January and February of 2025. Fabrication is scheduled to begin in 2025, with installation set to commence in 2026 and continue through 2027. The necessary air permits for the expansion have already been received, ensuring a smooth transition to the next phase of the project.
As Santee Cooper seeks to balance reliability with sustainability, combined-cycle technology continues to play a crucial role in the transition toward cleaner energy solutions. The upgrade at Rainey Generation Station marks another milestone in the industry’s evolution, ensuring a resilient power infrastructure for years to come.