ST STEPHEN
OperatingHydro power plant
- Capacity
- 84 MW
- Primary fuel
- Hydro
- County
- Berkeley County
- Operator
- US ARMY CORPS OF ENGINEERS
- Status
- Operating
- Commissioned
- 1985
- EIA plant ID
- 6789
- Generators
- 3
- Technology
- Conventional Hydroelectric
- Net generation (2024)
- 259 GWh
- Capacity factor (2024, EIA nameplate)
- 35%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 33.4267, -79.9310
ST STEPHEN, an 84 MW Hydro power plant in Berkeley County, South Carolina. Operated by US ARMY CORPS OF ENGINEERS, commissioned 1985.
How ST STEPHEN compares
With 84 MW of capacity, ST STEPHEN ranks 33rd among the 83 operating power plants Bywatts maps in South Carolina and 7th of the 28 operating Hydro plants in the state. It accounts for about 2.5% of South Carolina's operating Hydro capacity and 0.4% of all operating capacity in the state. Nationally it is the 204th-largest of the 1,243 operating Hydro plants in the database. Commissioned in 1985, it is newer than 47% of the 82 operating South Carolina plants with a recorded commissioning year. It shares Berkeley County with 5 other operating plants, including CROSS and WILLIAMS.
EIA-860 lists 3 generators at the site with 84 MW of nameplate capacity, all conventional hydroelectric technology. Net generation was 259 GWh in 2024 (a 35% capacity factor), up 58% from 2022.
Grid neighborhood
The closest transmission line found within 10 miles is a 115 kV line, under 0.1 miles away. Another 4 operating power plants totaling 2,628 MW sit within 25 miles; the largest is CROSS (2,390 MW, Coal).
Computed by Bywatts from HIFLD power plant and transmission line records and EIA-860/923 survey data; distances are straight-line. Sources and methodology
Weather peril exposure
ST STEPHEN is an 84 MW hydro power plant in Berkeley County, SC, operated by US ARMY CORPS OF ENGINEERS, commissioned in 1985. Berkeley County carries critical modeled catastrophe exposure in the FEMA National Risk Index, scoring 4.5 of 5 at the 86th national percentile. Hurricane is the leading peril, rated Very High by FEMA at the 98th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a hydro plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Berkeley County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Hurricane | Very High | 98th | 4.9 of 5 | 0.32 |
| Earthquake | Relatively Moderate | 96th | 4.8 of 5 | <0.01 |
| Ice storm | Relatively High | 74th | 3.9 of 5 | 1.0 |
| Wildfire | Relatively Moderate | 70th | 3.8 of 5 | <0.01 |
| Coastal flooding | Relatively Moderate | 69th | 3.7 of 5 | 3.6 |
| Lightning | Relatively High | 67th | 3.7 of 5 | 64.4 |
| Heat wave | Relatively Low | 45th | 2.8 of 5 | 9.7 |
| Tornado | Relatively Moderate | 28th | 2.1 of 5 | 0.60 |
| Hail | Relatively Low | 25th | 2.0 of 5 | 2.7 |
| Riverine flooding | Relatively Moderate | 20th | 1.8 of 5 | 1.6 |
| Strong wind | Relatively Moderate | 3rd | 1.1 of 5 | 2.6 |
| Winter weather | Relatively Moderate | 2nd | 1.1 of 5 | 1.2 |
Model hail, wind and flood exposure for Berkeley County in the weather risk calculator
Ratings are the FEMA National Risk Index county hazard ratings; the peril score is a Bywatts transform of the FEMA national percentile. Full data sources and the solar vulnerability methodology are in the weather risk calculator.
Modeled estimate for screening and negotiation. Built from FEMA National Risk Index county hazard data and a solar vulnerability layer documented above. Not a quote, a binder, or actuarial advice, and not a substitute for a carrier's own model. Hazard data: FEMA National Risk Index December 2025, synced 2026-07-24. Resolution is county level, not site level.