Rainbow (MT)
Cascade County, Montana · EIA plant ID 2193 · Operator: NorthWestern Energy
Nameplate59MWSummer 64 MW
Generators1in service
Net generation299GWh12 mo to Dec 2025
Capacity factor53%hydro units, summer MW
Heat rate—thermal plants only
First online2013
Monthly net generation
EIA-923, all units at the plant. Net of station use; storage can go negative.
FinalPreliminary
Capacity factor by year
Net MWh ÷ (summer MW × hours), hydro units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
Heat rate by year
Electric fuel MMBtu × 1000 ÷ net MWh (Btu/kWh, HHV), fossil units only; CT + CA counted as one combined-cycle block.
Heat rate applies to fuel-burning (thermal) units only.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2001 | 195.4 | 66.0% | — |
| 2002 | 205.5 | 65.9% | — |
| 2003 | 215.6 | 69.1% | — |
| 2004 | 212 | 67.8% | — |
| 2005 | 232.7 | 74.6% | — |
| 2006 | 238.2 | 76.4% | — |
| 2007 | 228.9 | 73.4% | — |
| 2008 | 239.9 | 75.9% | — |
| 2009 | 268.1 | 85.0% | — |
| 2010 | 252.5 | 80.1% | — |
| 2011 | 230.6 | 73.1% | — |
| 2012 | 241.2 | 76.3% | — |
| 2013 | 289.2 | 55.4% | — |
| 2014 | 367.2 | 69.3% | — |
| 2015 | 347.7 | 65.6% | — |
| 2016 | 343.2 | 64.6% | — |
| 2017 | 376 | 71.0% | — |
| 2018 | 398.8 | 71.1% | — |
| 2019 | 453.4 | 80.9% | — |
| 2020 | 402.1 | 71.5% | — |
| 2021 | 308.4 | 55.0% | — |
| 2022 | 294 | 52.4% | — |
| 2023 | 394.9 | 70.4% | — |
| 2024 | 329 | 58.5% | — |
| 2025 | 298.6 | 53.3% | — |
Generators
EIA-860 (annual) with EIA-860M updates through Sep 2026. EIA-923 reports generation by plant, prime mover and fuel, not by unit, so unit-level output isn't shown.
| Gen ID | Technology | Prime mover | Nameplate MW | Summer MW | Online | Status | Planned retirement | OEM / model |
|---|---|---|---|---|---|---|---|---|
| RAI9 | Conventional Hydroelectric | HY | 59 | 64 | Mar 2013 | Operating | — | coming soon |
| RAI1 | Conventional Hydroelectric | HY | 4.5 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI2 | Conventional Hydroelectric | HY | 4.5 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI3 | Conventional Hydroelectric | HY | 4 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI4 | Conventional Hydroelectric | HY | 4 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI5 | Conventional Hydroelectric | HY | 4 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI6 | Conventional Hydroelectric | HY | 4 | 4 | Jul 1910 | Retired Apr 2013 | — | coming soon |
| RAI7 | Conventional Hydroelectric | HY | 5.8 | 6 | Sep 1917 | Retired Apr 2013 | — | coming soon |
| RAI8 | Conventional Hydroelectric | HY | 5.8 | 6 | Sep 1917 | Retired Apr 2013 | — | coming soon |
Owner / operator
Operator: NorthWestern Energy. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| NorthWestern Energy | 100.0% | 59 MW |
Nearby plants
Within 80 km.
| Cochrane | 59 MW | 0.8 km |
| Black Eagle Solar, LLC | 3 MW | 4 km |
| Black Eagle | 27 MW | 4.5 km |
| Ryan | 55 MW | 7.3 km |
| Morony | 63 MW | 12 km |
| Horseshoe Bend Wind Park | 10 MW | 18.1 km |