30th largest plant in Montana · 3394th nationally
Rainbow (Mt) is a hydroelectric power plant in Montana with a nameplate capacity of 59.0 MW. It generates roughly 394.9k MWh per year — enough to power about 37,607 average U.S. homes.
Its capacity factor of 76% puts it in the middle range — running steadily but not full-time.
| Plant Name | Rainbow (Mt) |
|---|---|
| Operator | Northwestern Energy (Mt Hydro) |
| City | Great Falls |
| County | Cascade County |
| State | Montana |
| ZIP | 59404 |
| Coordinates | 47.53440, -111.20450 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| RAI9 | Conventional Hydroelectric | Water | 59.0 MW | Operating | 2013 |
| RAI7 | Conventional Hydroelectric | Water | 5.8 MW | Retired | 1917 |
| RAI8 | Conventional Hydroelectric | Water | 5.8 MW | Retired | 1917 |
| RAI1 | Conventional Hydroelectric | Water | 4.5 MW | Retired | 1910 |
| RAI2 | Conventional Hydroelectric | Water | 4.5 MW | Retired | 1910 |
| RAI3 | Conventional Hydroelectric | Water | 4.0 MW | Retired | 1910 |
| RAI4 | Conventional Hydroelectric | Water | 4.0 MW | Retired | 1910 |
| RAI5 | Conventional Hydroelectric | Water | 4.0 MW | Retired | 1910 |
| RAI6 | Conventional Hydroelectric | Water | 4.0 MW | Retired | 1910 |
| NERC Region | WECC |
|---|---|
| Balancing Authority | Northwestern Energy (Nwmt) |
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.