Markham — Plant Summary
- EIA Plant ID
- 2980
- Capacity
- 128.4 MW
- Primary Fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Status
- Operating
- Location
- Mayes, OK
- Operating Since
- 1964
- Generators
- 4
- Operator
- Grand River Dam Authority
- Parent Company
- Grand River Dam Authority
- Annual Generation
- 188,164 MWh
- Capacity Factor
- 16.7%
- Balancing Authority
- Southwest Power Pool
- ISO/RTO
- SPP
- NERC Region
- MRO
Markham
OperatingHydro
Ranked #3 of 11 Hydro plants in OK#151 of 1454 nationally
128.4 MW Hydro operating in Mayes, OK — Southwest Power Pool
EIAGEMWD
128.4 MW
Nameplate Capacity
4
Generators
units
Conventional Hydroelectric
Technology
1964
Operating Since
Location
Coordinates
36.2317, -95.1822
County
Mayes, OK
Nearby Plants
- SalinaHydro259.2 MW · 7.9 km
- ChouteauNatural Gas1069.6 MW · 8.6 km
- Grand River Energy Center SolarSolar84 MW · 10.3 km
Ownership & Operator
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Grand River Dam Authority | Grand River Dam Authority | — |
| Owner(s) | Grand River Dam Authority | Grand River Dam Authority | — |
| Status | Operating | operating | — |
Ownership Chain
About
The Markham hydroelectric plant is located in Mayes County, Oklahoma. It is owned and operated by the Grand River Dam Authority (GRDA). The plant has a total capacity of 128.4 MW consisting of 4 generators utilizing conventional hydroelectric technology. The plant began operating in 1964 and its primary fuel source is water (WAT). Markham operates within the Southwest Power Pool (SPP) balancing authority and the Midwest Reliability Organization (MRO) NERC region.
In the most recent year with available data, Markham generated 188,164 MWh of electricity, resulting in a capacity factor of 16.7%. Financial data indicates a power purchase agreement (PPA) price of $8.5 per MWh, as reported to FERC. Markham is the third-largest of five hydroelectric plants in Oklahoma, and ranks 151st out of 194 hydroelectric plants nationally.
Generated from EIA, GEM, and public data sources
Engineering & Generators
Grid Context
NERC Region
MRO
Balancing Authority
Southwest Power Pool
Grid Voltage
161 kV
Regulatory Status
RE
Entity Type
State
Sector
Electric Utility
Generation
4.7K MWh
Latest Month
188.2K MWh
Annual Generation
16.7%
Capacity Factor
Jan 2022 – Dec 2024
Financial DataBeta
Source: FERC Electric Quarterly ReportsHIGH
$8.5/MWh
PPA Price
Grand River Dam Authority
Contract Seller
Per-Unit Cost Trends
Pricing & Market Data
HIGH confidencePoint of Interconnection
Nearest Substation
Kerr Substation · 161 kV
Substation Distance
< 10 km
Operator
Grand River Dam Authority
Coord Source
OSM spatial
Market Position
ISO/RTO Market
SPP
LMP Node
GRDAKERR_HYDUN1
Pricing Hub
SPP South Hub
Node Source
EIA-860 direct report
News & Articles (10)Beta
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Last updated 2026-03-21
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