Holter
Holter is a 55 MW hydroelectric power plant in Cascade County, Montana, operated by NorthWestern Energy (MT Hydro). EIA-860M lists 4 generating units here. Its units entered service in 1918.
As of 2026-07 (inventory dated 2026-07-31) · EIA-860M Preliminary Monthly Electric Generator Inventory · eia.gov/…/july_generator2026.xlsx · eia.gov/…/eia860m
- Nameplate capacity
- 54.6 MW
- 57 MW net summer
- Generating units
- 4
- In service
- 1918
- EIA plant ID
- 2186
Where it is
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- County
- Cascade County, Montana
- Coordinates
- 46.9915, -112.0047
- Balancing authority
- NWMT
- Sector
- Electric Utility
Units, technology and status
- Operator of record
- NorthWestern Energy (MT Hydro)
- Primary energy source
- Hydro
- Technologies
- Conventional Hydroelectric
- Status
- Operating (3) · Out of service but expected to return to service in next calendar year (1)
Holter: FAQ
- Where is Holter?
- In Cascade County, Montana (MT). The map on this page is placed at the coordinates EIA files for the plant, which locate the site rather than any individual unit.
- How big is Holter?
- 55 MW of nameplate capacity across 4 units, as of the EIA-860M release for 2026-07.
- Who owns Holter?
- EIA-860M names NorthWestern Energy (MT Hydro) as the reporting entity. That is the operator of record on the survey, which is not always the ultimate owner.
- Is this the same as Holter LLC?
- Probably, but EIA-860M does not say. The survey records a plant name and a reporting entity — NorthWestern Energy (MT Hydro) here — not the project company that holds the asset. Project companies are commonly registered as an LLC carrying the plant's name, so a search for "Holter LLC" usually means this site. This page shows only what EIA files, and does not assert a corporate structure it cannot see.
- Is Holter still running?
- EIA-860M files it as "Operating" for 2026-07. Statuses change monthly, and this page follows the monthly release.