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583.4 MW Hydro operating in Mercer, ND — Southwest Power Pool
583.4 MW
Nameplate Capacity
5
Generators
units
Conventional Hydroelectric
Technology
1956
Operating Since
Coordinates
47.4945, -101.4115
County
Mercer, ND
Nearby Plants
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-Omaha | US Army Corps of Engineers - Omaha District | — |
| Owner(s) | USACE-Omaha | US Army Corps of Engineers - Omaha District | — |
| Status | Operating | operating | — |
GEM identifies the owner as US Army Corps of Engineers - Omaha District
This entity is not yet in the GEM ownership database — chain unavailable.

Garrison Dam is an earth-fill embankment dam on the Missouri River in central North Dakota, U.S. Constructed by the U.S. Army Corps of Engineers from 1947 to 1953, at over two miles (3.2 km) in length, the dam is the fifth-largest earthen dam in the world. The reservoir impounded by the dam is Lake Sakakawea, which extends to Williston and the confluence with the Yellowstone River, near the Montana border. The dam and resulting reservoir inundated approximately one-sixth (16.6%) to one-fourth (25%) of Fort Berthold Indian Reservation's land, resulting in the loss of homes, farmland, and community infrastructure for the Three Affiliated Tribes.
Read more on WikipediaThe Garrison hydroelectric plant, located in Mercer County, North Dakota, has a total capacity of 583.4 MW across five generators. It commenced operations in 1956 and is owned and operated by USACE-Omaha. The plant utilizes water as its primary fuel source and employs conventional hydroelectric technology. Garrison is the largest hydroelectric plant in North Dakota and ranks 44th nationally among 194 hydroelectric facilities.
In the latest annual reporting period, the plant generated 2,060,635 MWh of electricity, achieving a capacity factor of 40.3%. The Garrison plant operates within the Southwest Power Pool (SPP) balancing authority and is situated in the Midwest Reliability Organization (MRO) NERC region.
Generated from EIA, GEM, and public data sources
ISO/RTO
SPP
Market
ISO/RTO Member
NERC Region
MRO — Midwest Reliability Organization
Balancing Authority
148.9K MWh
Latest Month
2.1M MWh
Annual Generation
40.3%
Capacity Factor
2013
$2,294/kW
Est. Construction Cost
Total estimated cost: $1.3B
Market Position
ISO/RTO Market
SPP
LMP Node
WAUE.GARRISON.1_3
Pricing Hub
SPP North Hub
Location Type
Settlement Location
Node Source
Curated node match
Last updated 2026-03-26
View all 5 articlesNo ask pi reports yet for this entity.
ask pi about GarrisonSouthwest Power Pool (SWPP)
Grid Voltage
230.0 kV
Regulatory Status
RE — Regulated
Entity Type
Federal
Sector
Electric Utility