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Rainbow (MT) — Power plant · Hydro · NorthWestern Energy (MT Hydro)
  • Clean firm
  • Operating
  • 10 · 100 · 1,000 MW

Rainbow (MT)

Power plant · Hydro

Key facts

Power plant · Hydroran 58% of 2025 Operating
Capacity
Capacity: sourceEIA-860M · Open licenseMW
Commissioned
2013
Net generation, 2025
298,642 MWh
Grid
100 kV to NorthWestern Energy LLC - (MT) (NWMT)
Location
Cascade County, Montana
Operated by
NorthWestern Energy (MT Hydro)SourceEIA-860M Preliminary Monthly Electric Generator Inventory

Output

Net generation MWh by year, 2001 to 2025

Operations detail

Details

Who’s behind it

No companies named in filings yet.

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Technology
Hydro source: “Conventional Hydroelectric”
Age
13 years since 2013
All 5 attributes from EIA-860M Preliminary Monthly Electric Generator Inventory
AttributeValue
Gem
Unit ids
G100001027546
Location id
L100001023341
Fuel burned (MMBtu), 20251,018,967
Capacity factor, 20250.578
Net generation (MWh), 2025298,642
Balancing authority codeNWMT

Retirement

EIA-860M September 2026StatusSome generators have retired; the rest of the plant is still in service. As of EIA-860M for September 2026.
Capacity retired
36.6 MW
Generators retired
8
Capacity still in service
59 MW
GeneratorTechnologyNameplateStateDate
RAI1Conventional Hydroelectric4.5 MWRetiredApril 2013
RAI2Conventional Hydroelectric4.5 MWRetiredApril 2013
RAI3Conventional Hydroelectric4 MWRetiredApril 2013
RAI4Conventional Hydroelectric4 MWRetiredApril 2013
RAI5Conventional Hydroelectric4 MWRetiredApril 2013
RAI6Conventional Hydroelectric4 MWRetiredApril 2013
RAI7Conventional Hydroelectric5.8 MWRetiredApril 2013
RAI8Conventional Hydroelectric5.8 MWRetiredApril 2013

Grid

EIA-860 2025Grid fieldsAs the plant reported them to EIA-860 for 2025 (Schedule 2).
Grid voltage at the plant
100 kV
Transmission or distribution system owner
NorthWestern Energy LLC - (MT)
Balancing authority
NorthWestern Energy (NWMT)
NERC region
WECC
Can the connection be reused?

A plant that retires usually leaves its substation, transmission connection and interconnection agreement behind, and those may be reusable by a new project at the same site. FERC Order No. 845 lets an interconnection customer use surplus interconnection service at an existing site, and some transmission providers' tariffs let a replacement resource take over a retiring unit's interconnection service, usually within a set time after the retirement. Whether any such right still exists here, who holds it and on what terms depends on the owner, the transmission provider and timing; this page does not establish any of that.

Timeline

  • Stated Units RAI1, RAI2, RAI3, RAI4, RAI5, RAI6, RAI7, RAI8 scheduled to retire, 36.6 MW · EIA-860M
  • In service · EIA-860M

Sources

4 sources

Sources EIA-860M · GEM · EIA · EIA-860M Preliminary Monthly Electric Generator Inventory

Sources

Every source and license · Attribution

View at source