Markham
Hydro power plant in Mayes County, Oklahoma. 128.4 MW of nameplate capacity across 4 generators, operated by Grand River Dam Authority.
Also known as Markham Power Plant · EIA plant 2980
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 128.4 MWNameplate
- Generators
- 4 operatingEIA-860M, August 2026
- Operating since
- May 1964First generator online
- Operator
- Grand River Dam AuthorityEIA operator ID 7490
- Grid
- SPPBalancing authority SWPP
- Price nodes
- 4 SPP nodesResource nodes with prices
- Location
- Mayes County, OK36.2317, −95.1822
- EIA plant ID
- 2980EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Markham produces
Free · EIA-923Net generation, 2025
288 GWh
288,136 MWh, final
Capacity factor, 2025
25.6%
2024: 16.7%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
123.5–549.2
GWh a year. Low 2023, high 2019
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | 146,471 | Not reported | 12 of 12 |
| 2001 | 176,071 | Not reported | 12 of 12 |
| 2002 | 150,897 | Not reported | 12 of 12 |
| 2003 | 112,284 | Not reported | 12 of 12 |
| 2004 | 287,962 | Not reported | 12 of 12 |
| 2005 | 272,746 | Not reported | 12 of 12 |
| 2006 | 39,643 | Not reported | 12 of 12 |
| 2007 | 272,695 | Not reported | 12 of 12 |
| 2008 | 403,128 | Not reported | 12 of 12 |
| 2009 | 378,248 | Not reported | 12 of 12 |
| 2010 | 277,762 | Not reported | 12 of 12 |
| 2011 | 170,798 | 15.7% | 12 of 12 |
| 2012 | 95,618 | 8.8% | 12 of 12 |
| 2013 | 253,738 | Not reported | 12 of 12 |
| 2014 | 111,265 | Not reported | 12 of 12 |
| 2015 | 347,677 | 30.9% | 12 of 12 |
| 2016 | 251,699 | 22.3% | 12 of 12 |
| 2017 | 248,572 | 22.1% | 12 of 12 |
| 2018 | 176,311 | 15.7% | 12 of 12 |
| 2019 | 549,249 | 48.8% | 12 of 12 |
| 2020 | 337,870 | 30.0% | 12 of 12 |
| 2021 | 287,744 | 25.6% | 12 of 12 |
| 2022 | 210,821 | 18.7% | 12 of 12 |
| 2023 | 123,474 | 11.0% | 12 of 12 |
| 2024 | 188,164 | 16.7% | 12 of 12 |
| 2025 | 288,136 | 25.6% | 12 of 12 |
| 2026 (provisional, partial year) | Not reported | Not reported | 0 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free account · SPPEmissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 1 | Conventional Hydroelectric | 32.1 | May 1964 |
| 2 | Conventional Hydroelectric | 32.1 | May 1964 |
| 3 | Conventional Hydroelectric | 32.1 | May 1964 |
| 4 | Conventional Hydroelectric | 32.1 | May 1964 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists Grand River Dam Authority as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
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Power plants near Markham
More plants operated by Grand River Dam Authority
Questions about Markham
How much power does Markham produce?
Markham reported 288,136 MWh (288 GWh) of net generation in 2025, a 25.6% capacity factor on 128.4 MW of nameplate capacity.
Where is Markham?
Markham is in Mayes County, Oklahoma, at 36.2317, −95.1822. It is in the Southwest Power Pool balancing area (SWPP).
Who operates Markham?
EIA-860M for August 2026 lists Grand River Dam Authority as the operator (EIA operator ID 7490). The operator is not always the owner.
When did Markham start operating?
Its first generator began operating in May 1964, according to EIA-860M.
Does InfraMap have power prices for Markham?
Yes. InfraMap has SPP day-ahead and real-time prices at 4 price nodes linked to Markham, with the hub price and node-to-hub basis. Prices are free with an InfraMap account; pricing node names are part of InfraMap Pro.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- SPP day-ahead and real-time prices; node and hub assignments as of 2026-10-05
- Plant names from OpenStreetMap, © OpenStreetMap contributors (ODbL)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page