23rd largest plant in Washington · 1037th nationally
Mossyrock is a hydroelectric power plant in Washington with a nameplate capacity of 300 MW. It generates roughly 713.4k MWh per year — enough to power about 67,939 average U.S. homes.
Its capacity factor of 27% reflects intermittent or peaking operation.
| Plant Name | Mossyrock |
|---|---|
| Operator | City Of Tacoma - (Wa) |
| City | Silver Creek |
| County | Lewis County |
| State | Washington |
| ZIP | 98585 |
| Coordinates | 46.53470, -122.42470 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| 51 | Conventional Hydroelectric | Water | 150 MW | Operating | 1968 |
| 52 | Conventional Hydroelectric | Water | 150 MW | Operating | 1968 |
| NERC Region | WECC |
|---|---|
| Balancing Authority | City Of Tacoma, Department Of Public Utilities, Light Division |
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.