46th largest plant in Washington · 2047th nationally
Merwin is a hydroelectric power plant in Washington with a nameplate capacity of 136 MW. It generates roughly 471.6k MWh per year — enough to power about 44,912 average U.S. homes.
Its capacity factor of 40% reflects intermittent or peaking operation.
| Plant Name | Merwin |
|---|---|
| Operator | Pacificorp |
| City | Ariel |
| County | Cowlitz County |
| State | Washington |
| ZIP | 98603 |
| Coordinates | 45.95670, -122.55444 |
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 | 45.0 MW | Operating | 1932 |
| 2 | Conventional Hydroelectric | Water | 45.0 MW | Operating | 1949 |
| 3 | Conventional Hydroelectric | Water | 45.0 MW | Operating | 1958 |
| House | Conventional Hydroelectric | Water | 1.0 MW | Operating | 1931 |
| NERC Region | WECC |
|---|---|
| Balancing Authority | Pacificorp - West |
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.