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810 MW Hydro operating in Walla Walla, WA
810 MW
Nameplate Capacity
6
Generators
units
Conventional Hydroelectric
Technology
1969
Operating Since
Coordinates
46.5635, -118.5397
County
Walla Walla, WA
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Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | USACE Northwestern Division | US Army Corps of Engineers - Walla Walla District | United States Army Corps of Engineers |
| Owner(s) | USACE Northwestern Division | US Army Corps of Engineers - Walla Walla District | — |
| Status | Operating | operating | — |
GEM identifies the owner as US Army Corps of Engineers - Walla Walla District
This entity is not yet in the GEM ownership database — chain unavailable.
Lower Monumental Lock and Dam is a hydroelectric, concrete, run-of-the-river dam in the northwest United States. Located on the lower Snake River in southeast Washington, it bridges Franklin and Walla Walla counties; it is six miles (10 km) south of Kahlotus and 43 miles (70 km) north of Walla Walla.
Read more on WikipediaLower Monumental is a hydroelectric power plant located in Walla Walla County, Washington. The plant, which began operating in 1969, has a total capacity of 810 MW distributed across six generators. It is owned and operated by the USACE Northwestern Division. The plant uses water as its primary fuel source and employs conventional hydroelectric technology. Lower Monumental ranks as the 10th largest power plant in Washington state out of 23, and 31st nationally out of 194 plants.
In the most recent year with available data, Lower Monumental generated 1,476,976 MWh of electricity, resulting in a capacity factor of 20.8%. The plant operates within the Bonneville Power Administration balancing authority and the Western Electricity Coordinating Council (WECC) NERC region. Recent news coverage of the plant includes 10 articles, with a focus on regulatory matters.
Generated from EIA, GEM, and public data sources
Grid Region
Pacific Northwest
Market
WEIM Participant
NERC Region
WECC — Western Electricity Coordinating Council
Balancing Authority
Bonneville Power Administration (BPAT)
Grid Voltage
500.0 kV
Regulatory Status
RE — Regulated
Entity Type
Federal
Sector
Electric Utility
Monthly net generation as reported to EIA-923 — useful for historical context. Confidence varies sharply by fuel type; the band above and the “About this data” button explain the caveats specific to this plant and how InfraSure’s in-house model handles them.
195.9K MWh
Latest Month
1.5M MWh
Annual Generation
20.8%
Capacity Factor
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2013
$2,294/kW
Est. Construction Cost
Total estimated cost: $1.9B
Forward revenue, DSCR bands, and refinancing risk projected under price, demand, and policy scenarios. Powered by InfraSure's asset cashflow stack.
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This plant's balancing authority participates in CAISO's Western Energy Imbalance Market (WEIM). Direct nodal pricing data is not yet available.
No wholesale contracts disclosed in FERC EQR for this plant.
FERC EQR captures bilateral wholesale energy + capacity contracts ≥$1M/yr filed quarterly by jurisdictional sellers — covers renewable PPAs, thermal energy sales agreements, capacity contracts, and tolling agreements alike. Many plants don't appear: regulated-utility output flows to ratepayers via cost-of-service rather than bilateral contracts; small projects fall below the filing threshold; tax-equity-financed renewables route offtake to investors not utilities; merchant plants sell into ISO clearing markets without bilateral contracts. News-extracted buyer facts (below) may surface contracts disclosed only through announcements.
Last updated 2026-03-26
View all 5 articlesForward forecasts, scenario decomposition, and risk-decision tooling for this asset.
Analysis published on economic and agricultural fallout if the four lower Snake River dams, including Lower Monumental, were demolished.
sourceNew US energy secretary publicly declares strong support for keeping all four lower Snake River dams, including Lower Monumental, in place.
source