DAVE JOHNSTON
OperatingCoal power plant
- Capacity
- 817 MW
- Primary fuel
- Coal
- County
- Converse County
- Operator
- PACIFICORP
- Status
- Operating
- Commissioned
- 1959
- EIA plant ID
- 4158
- Generators
- 4
- Technology
- Conventional Steam Coal
- Net generation (2024)
- 3,839 GWh
- Capacity factor (2024, EIA nameplate)
- 54%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 42.8379, -105.7774
DAVE JOHNSTON, an 817 MW Coal power plant in Converse County, Wyoming. Operated by PACIFICORP, commissioned 1959.
How DAVE JOHNSTON compares
With 817 MW of capacity, DAVE JOHNSTON ranks 3rd among the 53 operating power plants Bywatts maps in Wyoming and 2nd of the 8 operating Coal plants in the state. It accounts for about 18% of Wyoming's operating Coal capacity and 9.5% of all operating capacity in the state. Nationally it is the 124th-largest of the 324 operating Coal plants in the database. Commissioned in 1959, it is older than 73% of the 53 operating Wyoming plants with a recorded commissioning year. Its operator, PACIFICORP, runs 10 operating plants in Wyoming totaling 4,823 MW. It shares Converse County with 4 other operating plants, including TOP OF THE WORLD WINDPOWER PROJECT and GLENROCK.
EIA-860 lists 4 generators at the site with 817 MW of nameplate capacity, all conventional steam coal technology. Net generation was 3,839 GWh in 2024 (a 54% capacity factor), up 7% from 2022. Its generators came online between 1959 and 1972.
Grid neighborhood
The nearest named substation is TAP (DAVE JOHNSTON), about 1.5 miles away; the closest transmission line found within 10 miles is a 230 kV line owned by PACIFICORP, under 0.1 miles away. Another 5 operating power plants totaling 563 MW sit within 25 miles; the largest is TOP OF THE WORLD WINDPOWER PROJECT (200 MW, Wind).
Computed by Bywatts from HIFLD power plant, substation and transmission line records and EIA-860/923 survey data; distances are straight-line. Sources and methodology
Weather peril exposure
DAVE JOHNSTON is an 817 MW coal power plant in Converse County, WY, operated by PACIFICORP, commissioned in 1959. Converse County carries elevated modeled catastrophe exposure in the FEMA National Risk Index, scoring 3.1 of 5 at the 53rd national percentile. Wildfire is the leading peril, rated Relatively Moderate by FEMA at the 91st 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.
Converse County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Wildfire | Relatively Moderate | 91st | 4.6 of 5 | <0.01 |
| Winter weather | Relatively Moderate | 77th | 4.1 of 5 | 19.1 |
| Riverine flooding | Relatively Low | 77th | 4.1 of 5 | 0.18 |
| Earthquake | Very Low | 75th | 4.0 of 5 | <0.01 |
| Hail | Relatively Low | 62nd | 3.5 of 5 | 1.4 |
| Lightning | Relatively Low | 47th | 2.9 of 5 | 42.2 |
| Tornado | Very Low | 25th | 2.0 of 5 | 0.69 |
| Ice storm | Very Low | 24th | 2.0 of 5 | 0.02 |
| Heat wave | Very Low | 12th | 1.5 of 5 | 0.17 |
| Strong wind | Very Low | 4th | 1.2 of 5 | 0.43 |
Perils not assessed in Converse 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 |
|---|---|
| Hurricane | FEMA rating is "Not Applicable" for this county |
| Coastal flooding | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for Converse 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.