8th largest plant in Washington · 416th nationally
Lower Granite is a hydroelectric power plant in Washington with a nameplate capacity of 810 MW. It generates roughly 1.5M MWh per year — enough to power about 146,835 average U.S. homes.
Its capacity factor of 22% reflects intermittent or peaking operation.
| Plant Name | Lower Granite |
|---|---|
| Operator | Usace Northwestern Division |
| City | Pomeroy |
| County | Whitman County |
| State | Washington |
| ZIP | 99347 |
| Coordinates | 46.65950, -117.42938 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| 1 | Conventional Hydroelectric | Water | 135 MW | Operating | 1975 |
| 2 | Conventional Hydroelectric | Water | 135 MW | Operating | 1975 |
| 3 | Conventional Hydroelectric | Water | 135 MW | Operating | 1975 |
| 4 | Conventional Hydroelectric | Water | 135 MW | Operating | 1978 |
| 5 | Conventional Hydroelectric | Water | 135 MW | Operating | 1978 |
| 6 | Conventional Hydroelectric | Water | 135 MW | Operating | 1978 |
| NERC Region | WECC |
|---|---|
| Balancing Authority | Bonneville Power Administration |
Hydroelectric plants spin turbines using falling or flowing water — typically from a dam-impounded reservoir. They are dispatchable, long-lived, and emission-free at the point of generation, though large reservoirs can disrupt rivers and ecosystems and methane can be released from flooded vegetation.