Twin Reservoirs
Hydro power plant · Walla Walla County, Washington
Details
- Primary fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Operator
- Walla Walla City of
- County
- Walla Walla County
- Generating units
- 1
- Share of state capacity
- 0.01%
- Rank among hydro plants in Washington
- #64 of 73
- EIA plant code
- 50382
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| GEN1 | Conventional Hydroelectric | 2.2 MW | 1.8 MW | 1988 | Operating |
Nameplate is the maximum rated output; summer capacity is what the unit can reliably deliver on a hot day, which is typically lower.
Similarly sized plants in Washington
| Potholes East Canal 66.0 | Hydro | 2.3 MW |
| Eltopia Branch Canal 4.6 | Hydro | 2.2 MW |
| Glacier Battery Storage | Battery storage | 2.0 MW |
| Meyers Falls | Hydro | 1.8 MW |
About this data
From EIA’s inventory of operable generators, May 2026 release. Capacity is nameplate — the maximum rated output of the equipment, not what the plant actually generates over a year, which depends on how often it runs. A 2.2 MW solar plant and a 2.2 MW nuclear plant have the same entry here and produce very different amounts of electricity.
“In service since” is the earliest in-service date among the units still listed, so a site rebuilt around newer equipment can read as younger than the site itself. All Washington power plants · What Washington actually generates