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786.1 MW Hydro operating in Hughes, SD — Southwest Power Pool
786.1 MW
Nameplate Capacity
7
Generators
units
Conventional Hydroelectric
Technology
1962
Operating Since
Coordinates
44.4504, -100.3866
County
Hughes, SD
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.
The Oahe Dam is a large earthen dam on the Missouri River, just north of Pierre, South Dakota, United States. Begun in 1948 and opened in 1962, the dam creates Lake Oahe, the fourth-largest man-made reservoir in the United States. The reservoir stretches 231 miles (372 km) up the course of the Missouri to Bismarck, North Dakota. The dam's power plant provides electricity for much of the north-central United States. It is named for the Oahe Indian Mission established among the Lakota Sioux in 1874.
Read more on WikipediaThe Oahe hydroelectric plant is located in Hughes County, South Dakota. It has a total capacity of 786.1 MW across 7 generators, making it the largest of three hydroelectric plants in the state. Nationally, it ranks as the 32nd largest out of 194 hydroelectric facilities. The plant began operating in 1962 and is operated by the US Army Corps of Engineers (USACE-Omaha). The primary fuel source is water ("WAT").
In the most recent year with available data, Oahe generated 2,188,759 MWh of electricity, achieving a capacity factor of 31.7%. The plant operates within the Southwest Power Pool (SPP) balancing authority and 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
100.8K MWh
Latest Month
2.2M MWh
Annual Generation
31.7%
Capacity Factor
2013
$2,294/kW
Est. Construction Cost
Total estimated cost: $1.8B
Point of Interconnection
Nearest Substation
Oahe Substation · 230 kV
Substation Distance
0 km
Coord Source
OSM spatial
Market Position
ISO/RTO Market
SPP
LMP Node
WAUE.OAHE.1
Pricing Hub
SPP North Hub
Location Type
Settlement Location
Node Source
Curated node match
Last updated 2026-03-26
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ask pi about OaheSouthwest Power Pool (SWPP)
Grid Voltage
230.0 kV
Regulatory Status
RE — Regulated
Entity Type
Federal
Sector
Electric Utility