Seminole Electric Cooperative is developing the gas-fired combined-cycle facility adjacent to the existing coal-fired Seminole Generating Station (SGS). Image courtesy of Seminole Electric.
The 1.05GW Seminole gas-fired power project is located in Putnam County, Florida, US. Image courtesy of Seminole Electric.
General Electric (GE) is supplying two 7HA.02 gas turbines for the Seminole combined-cycle facility (SCCF). Image courtesy of General Electric.

The Seminole combined-cycle power project is a 1GW natural gas-fired facility under construction in Florida, US.

Seminole Electric Cooperative, one of the biggest power generation and transmission co-operatives in the US with an approximately 1.8 million consumer base in Florida, is developing the project with an estimated investment of £582m ($727m).

The construction works on the project were started in March 2020, with commissioning expected in early 2023.

The Seminole combined-cycle facility (SCCF) is intended to displace one of the 650MW coal-fired units of the Seminole Generating Station (SGS), which has been operational since 1984.

Location and site details

The Seminole gas-fired combined-cycle power project is being developed on a 32-acre site adjacent to the existing 1.3GW coal-fired SGS facility near Palatka, Putnam County, Florida, US.

Seminole combined-cycle power plant make-up

The combined-cycle power station will be equipped with two 7HA.02 gas turbines, two duct-fired heat recovery steam generators (HRSG), and an STF-D652 steam turbine from General Electric (GE). The total installed capacity of the facility will be 1,050MW.

The plant will be furnished with a dry low-nitrogen oxide (NOx) combustor and a selective catalytic reduction (SCR) system to mitigate NOx emissions. It will also feature catalytic oxidation to curb carbon monoxide (CO) and volatile organic compound (VOC) emissions.

The other components of the project will include a 16-cell, closed-cycle mechanical draft cooling tower, piping tie-ins, exhaust stacks, and step-up transformers, apart from a stainless-steel demineralised water storage tank and a carbon steel fire protection water storage tank.

Infrastructure facilities

The SCCF will utilise the water intake and discharge structures, as well as the switchyard facility of the existing SGS coal-fired power station.

The other associated facilities for the project will include a control room, a maintenance area, a warehouse, a fuel gas regulation station, fuel gas heaters, and a diesel-fired emergency fire water pump, along with aqueous ammonia storage tanks, and a wastewater treatment facility.

Natural gas supply for the Seminole power plant

The natural gas for the Seminole combined-cycle power plant will be supplied by SeaCoast Gas Transmission, a subsidiary of Florida-based TECO Energy, through the 33.8km-long Palatka Lateral pipeline connecting the Putnam Hall natural gas line of the Florida Gas Transmission (FGT) system.

Completed in 2020, the Palatka Lateral natural gas pipeline project involved the installation of two mainline block valves (MLVs) and a pig launcher/receiver at the FGT gate station. The underground section of the Palatka Lateral pipeline measures approximately 3.8km long.

Water supply

The Seminole combined-cycle power plant will require 8.26 million gallons per day (MGD) of water for cooling, which will be sourced from the St. Johns River.

Power evacuation from the Seminole gas-fired facility

The electricity generated by the Seminole combined-cycle power plant will be evacuated into the Florida transmission network through a 230kV power transmission line.


The Seminole gas-fired power project is being financed through rural development loans from the United States Department of Agriculture (USDA).

Contractors involved

TIC, a wholly-owned subsidiary of Kiewit Corporation, was selected as the engineering, procurement and construction (EPC) contractor for the Seminole combined-cycle power project in April 2018.

GE was contracted for the supply of turbines and generator equipment for the project, while Flenco Fluid System was subcontracted by GE for the supply of auxiliary systems.

Black Start has been engaged for the start-up and commissioning of the plant. The contractual scope includes providing instrumentation and controls, as well as distributed control system (DCS) support services for the project.

Seminole Electric selected Hyperion Power Services as the owner’s engineer for the project in June 2019.

SeaCoast Gas Transmission was responsible for the construction of the gas pipeline connecting the Seminole combined-cycle project site.

Environmental Consulting and Technology (ECT), based in Florida, was engaged in site assessment, remediation, and monitoring of environmental compliance for the Seminole combined-cycle power project.