GRAND COULEE
OperatingHydro power plant
- Capacity
- 6,809 MW
- Primary fuel
- Hydro
- County
- Grant County
- Operator
- U S BUREAU OF RECLAMATION
- Status
- Operating
- Commissioned
- 1941
- EIA plant ID
- 6163
- Generators
- 33
- Technology
- Conventional Hydroelectric
- Net generation (2024)
- 15,443 GWh
- Capacity factor (2024, EIA nameplate)
- 26%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 47.9597, -118.9752
GRAND COULEE, a 6,809 MW Hydro power plant in Grant County, Washington. Operated by U S BUREAU OF RECLAMATION, commissioned 1941.
How GRAND COULEE compares
With 6,809 MW of capacity, GRAND COULEE is the largest of the 126 operating power plants Bywatts maps in Washington and the largest of the 65 operating Hydro plants in the state. It accounts for about 32% of Washington's operating Hydro capacity and 23% of all operating capacity in the state. Nationally it is the largest of the 1,243 operating Hydro plants in the database. Commissioned in 1941, it is older than 84% of the 125 operating Washington plants with a recorded commissioning year. Its operator, U S BUREAU OF RECLAMATION, runs 3 operating plants in Washington totaling 6,834 MW. It shares Grant County with 6 other operating plants, including WANAPUM and PRIEST RAPIDS.
EIA-860 lists 33 generators at the site with 6,809 MW of nameplate capacity, mainly conventional hydroelectric technology. Net generation was 15,443 GWh in 2024 (a 26% capacity factor), down 27% from 2022. Its generators came online between 1941 and 1984.
Grid neighborhood
The nearest named substation is GRAND COULEE 230KV (500 kV), about 1.1 miles away; the closest transmission line found within 10 miles is a 500 kV line owned by BONNEVILLE POWER ADMINISTRATION, under 0.1 miles away.
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
GRAND COULEE is a 6,809 MW hydro power plant in Grant County, WA, operated by U S BUREAU OF RECLAMATION, commissioned in 1941. Grant County carries low modeled catastrophe exposure in the FEMA National Risk Index, scoring 1.1 of 5 at the 2nd national percentile. Wildfire is the leading peril, rated Relatively Moderate by FEMA at the 93rd 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.
Grant County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Wildfire | Relatively Moderate | 93rd | 4.7 of 5 | <0.01 |
| Earthquake | Relatively Low | 83rd | 4.3 of 5 | <0.01 |
| Heat wave | Relatively Moderate | 63rd | 3.5 of 5 | 4.7 |
| Riverine flooding | Relatively Moderate | 22nd | 1.9 of 5 | 0.36 |
| Winter weather | Relatively Moderate | 17th | 1.7 of 5 | 9.7 |
| Lightning | Relatively Low | 10th | 1.4 of 5 | 9.2 |
| Strong wind | Relatively Low | 10th | 1.4 of 5 | 0.17 |
| Tornado | Very Low | 6th | 1.2 of 5 | 0.10 |
| Hail | Relatively Low | 2nd | 1.1 of 5 | 0.11 |
| Ice storm | Very Low | 0th | 1.0 of 5 | 0.01 |
Perils not assessed in Grant 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 Grant 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.