Twin Reservoirs
Hydro power plant in Walla Walla County, Washington. 2.2 MW of nameplate capacity across 1 generator, operated by City of Walla Walla - (WA).
Also known as EIA plant 50382
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 2.2 MWNameplate
- Generators
- 1 operatingEIA-860M, August 2026
- Operating since
- April 1988First generator online
- Operator
- City of Walla Walla - (WA)EIA operator ID 20032
- Grid
- BPATBalancing authority BPAT
- Price nodes
- None linkedNo verified ISO node
- Location
- Walla Walla County, WA46.0883, −118.2547
- EIA plant ID
- 50382EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Twin Reservoirs produces
Free · EIA-923Net generation, 2025
6.87 GWh
6,867 MWh, final
Capacity factor, 2025
35.6%
2024: 37.9%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
6.9–12.0
GWh a year. Low 2025, high 2016
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | 14,030 | Not reported | 12 of 12 |
| 2002 | 12,143 | Not reported | 12 of 12 |
| 2003 | 10,758 | Not reported | 12 of 12 |
| 2004 | 12,694 | Not reported | 12 of 12 |
| 2005 | 11,280 | Not reported | 12 of 12 |
| 2006 | 12,396 | Not reported | 12 of 12 |
| 2007 | 12,386 | Not reported | 12 of 12 |
| 2008 | 13,077 | Not reported | 12 of 12 |
| 2009 | 12,276 | Not reported | 12 of 12 |
| 2010 | 12,135 | 63.0% | 12 of 12 |
| 2011 | 13,254 | 68.8% | 12 of 12 |
| 2012 | 13,637 | 70.6% | 12 of 12 |
| 2013 | 12,838 | 66.6% | 12 of 12 |
| 2014 | 11,826 | 61.4% | 12 of 12 |
| 2015 | 11,659 | 60.5% | 12 of 12 |
| 2016 | 11,976 | 62.0% | 12 of 12 |
| 2017 | 11,917 | 61.8% | 12 of 12 |
| 2018 | 11,466 | 59.5% | 12 of 12 |
| 2019 | 8,118 | 42.1% | 12 of 12 |
| 2020 | 8,442 | 43.7% | 12 of 12 |
| 2021 | 10,883 | 56.5% | 12 of 12 |
| 2022 | 9,383 | 48.7% | 12 of 12 |
| 2023 | 8,139 | 42.2% | 12 of 12 |
| 2024 | 7,321 | 37.9% | 12 of 12 |
| 2025 | 6,867 | 35.6% | 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 |
|---|---|---|---|
| GEN1 | Conventional Hydroelectric | 2.2 | April 1988 |
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 City of Walla Walla - (WA) 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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Questions about Twin Reservoirs
How much power does Twin Reservoirs produce?
Twin Reservoirs reported 6,867 MWh (6.87 GWh) of net generation in 2025, a 35.6% capacity factor on 2.2 MW of nameplate capacity.
Where is Twin Reservoirs?
Twin Reservoirs is in Walla Walla County, Washington, at 46.0883, −118.2547. It is in the Bonneville Power Administration balancing area (BPAT).
Who operates Twin Reservoirs?
EIA-860M for August 2026 lists City of Walla Walla - (WA) as the operator (EIA operator ID 20032). The operator is not always the owner.
When did Twin Reservoirs start operating?
Its first generator began operating in April 1988, 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