SIOUX
OperatingCoal power plant
- Capacity
- 1,099 MW
- Primary fuel
- Coal
- County
- St. Charles County
- Operator
- UNION ELECTRIC CO - (MO)
- Status
- Operating
- Commissioned
- 1967
- EIA plant ID
- 2107
- Generators
- 2
- Technology
- Conventional Steam Coal
- Net generation (2024)
- 3,338 GWh
- Capacity factor (2024, EIA nameplate)
- 35%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 38.9153, -90.2913
SIOUX, a 1,099 MW Coal power plant in St. Charles County, Missouri. Operated by UNION ELECTRIC CO - (MO), commissioned 1967.
How SIOUX compares
With 1,099 MW of capacity, SIOUX ranks 6th among the 92 operating power plants Bywatts maps in Missouri and 5th of the 13 operating Coal plants in the state. It accounts for about 11% of Missouri's operating Coal capacity and 5.7% of all operating capacity in the state. Nationally it is the 105th-largest of the 324 operating Coal plants in the database. Commissioned in 1967, it is older than 75% of the 89 operating Missouri plants with a recorded commissioning year. Its operator, UNION ELECTRIC CO - (MO), runs 11 operating plants in Missouri totaling 6,645 MW.
EIA-860 lists 2 generators at the site with 1,099 MW of nameplate capacity, all conventional steam coal technology. Net generation was 3,338 GWh in 2024 (a 35% capacity factor), down 9% from 2022. Its generators came online between 1967 and 1968.
Grid neighborhood
The nearest named substation is SIOUX (345 kV), about 0.1 miles away; the closest transmission line found within 10 miles is a 138 kV line owned by UNION ELECTRIC CO - (MO), under 0.1 miles away. Another 6 operating power plants totaling 748 MW sit within 25 miles; the largest is VENICE (586 MW, Natural Gas). Within 50 miles are 2 mapped data centers; the nearest is 710 Tucker St Louis in St. Louis, about 20.2 miles away.
Computed by Bywatts from HIFLD power plant, substation and transmission line records, EIA-860/923 survey data and PeeringDB data center locations; distances are straight-line. Sources and methodology
Weather peril exposure
SIOUX is a 1,099 MW coal power plant in St. Charles County, MO, operated by UNION ELECTRIC CO - (MO), commissioned in 1967. St. Charles County carries critical modeled catastrophe exposure in the FEMA National Risk Index, scoring 4.2 of 5 at the 80th national percentile. Earthquake is the leading peril, rated Relatively Moderate by FEMA at the 87th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a coal plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
St. Charles County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Earthquake | Relatively Moderate | 87th | 4.5 of 5 | <0.01 |
| Riverine flooding | Relatively High | 84th | 4.4 of 5 | 2.1 |
| Hail | Relatively High | 84th | 4.3 of 5 | 5.3 |
| Tornado | Relatively High | 62nd | 3.5 of 5 | 0.46 |
| Heat wave | Relatively Moderate | 59th | 3.4 of 5 | 14.7 |
| Lightning | Relatively High | 59th | 3.4 of 5 | 51.0 |
| Winter weather | Relatively High | 59th | 3.3 of 5 | 8.8 |
| Ice storm | Relatively Moderate | 39th | 2.5 of 5 | 1.3 |
| Wildfire | Very Low | 38th | 2.5 of 5 | <0.01 |
| Strong wind | Very High | 38th | 2.5 of 5 | 5.9 |
| Hurricane | Very Low | 5th | 1.2 of 5 | <0.01 |
Perils not assessed in St. Charles County
These perils carry no usable National Risk Index figure for this county, so they are excluded from the scoring rather than scored zero. A zero would claim the peril was assessed and found benign.
| Peril | Why it is not scored |
|---|---|
| Coastal flooding | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for St. Charles 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.