Madison Dam
Hydro power plant in Madison County, Montana. 16.4 MW of nameplate capacity across 4 generators, operated by NorthWestern Energy (MT Hydro).
Also known as EIA plant 6422
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 16.4 MWNameplate
- Generators
- 4 operatingEIA-860M, August 2026
- Operating since
- December 2021First generator online
- Operator
- NorthWestern Energy (MT Hydro)EIA operator ID 13902
- Grid
- NWMTBalancing authority NWMT
- Price nodes
- None linkedNo verified ISO node
- Location
- Madison County, MT45.4879, −111.6338
- EIA plant ID
- 6422EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Madison Dam produces
Free · EIA-923Net generation, 2025
75.6 GWh
75,588 MWh, final
Capacity factor, 2025
52.6%
2024: 52.9%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
0.0–76.2
GWh a year. Low 2020, high 2024
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | 62,362 | Not reported | 12 of 12 |
| 2002 | 58,767 | Not reported | 12 of 12 |
| 2003 | 60,057 | Not reported | 12 of 12 |
| 2004 | 61,255 | Not reported | 12 of 12 |
| 2005 | 65,788 | Not reported | 12 of 12 |
| 2006 | 67,595 | Not reported | 12 of 12 |
| 2007 | 60,099 | Not reported | 12 of 12 |
| 2008 | 57,078 | Not reported | 12 of 12 |
| 2009 | 62,452 | Not reported | 12 of 12 |
| 2010 | 61,727 | 80.1% | 12 of 12 |
| 2011 | 65,131 | 84.5% | 12 of 12 |
| 2012 | 66,415 | 85.9% | 12 of 12 |
| 2013 | 56,473 | 73.3% | 12 of 12 |
| 2014 | 53,649 | 69.6% | 12 of 12 |
| 2015 | 59,401 | 77.1% | 12 of 12 |
| 2016 | 57,101 | 73.9% | 12 of 12 |
| 2017 | 62,279 | 80.8% | 12 of 12 |
| 2018 | 62,610 | 81.2% | 12 of 12 |
| 2019 | 51,327 | 66.6% | 12 of 12 |
| 2020 | 0 | 0.0% | 12 of 12 |
| 2021 | 1,136 | Not reported | 12 of 12 |
| 2022 | 65,416 | Not reported | 12 of 12 |
| 2023 | 57,545 | 40.1% | 12 of 12 |
| 2024 | 76,209 | 52.9% | 12 of 12 |
| 2025 | 75,588 | 52.6% | 12 of 12 |
| 2026 (provisional, partial year) | Not reported | Not reported | 0 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free accountNo verified ISO price node is linked to this plant, or its price history could not load.
Emissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| MAD5 | Conventional Hydroelectric | 4.1 | December 2021 |
| MAD6 | Conventional Hydroelectric | 4.1 | December 2021 |
| MAD7 | Conventional Hydroelectric | 4.1 | January 2022 |
| MAD8 | Conventional Hydroelectric | 4.1 | March 2022 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists NorthWestern Energy (MT Hydro) as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
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Power plants near Madison Dam
More plants operated by NorthWestern Energy (MT Hydro)
Questions about Madison Dam
How much power does Madison Dam produce?
Madison Dam reported 75,588 MWh (75.6 GWh) of net generation in 2025, a 52.6% capacity factor on 16.4 MW of nameplate capacity.
Where is Madison Dam?
Madison Dam is in Madison County, Montana, at 45.4879, −111.6338. It is in the NorthWestern Energy (NWMT) balancing area (NWMT).
Who operates Madison Dam?
EIA-860M for August 2026 lists NorthWestern Energy (MT Hydro) as the operator (EIA operator ID 13902). The operator is not always the owner.
When did Madison Dam start operating?
Its first generator began operating in December 2021, according to EIA-860M.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page