- Clean firm
- Operating
- 10 · 100 · 1,000 MW
Map
- Clean firm
- Operating
Markham: location. Basemap: Protomaps, © OpenStreetMap contributors, ODbL.
Markham
Power plant · Hydro
Key facts
Power plant · Hydroran 26% of 2025 Operating- Capacity
- Capacity: sourceEIA-860M · Open licenseMW
- Commissioned
- 1964
- Net generation, 2025
- 288,136 MWh
- Grid
- 161 kV, 115 kV to Grand River Dam Authority (SWPP)
- Location
- Mayes County, Oklahoma
- Operated by
- Grand River Dam AuthoritySourceEIA-860M Preliminary Monthly Electric Generator Inventory
Operations
- Net generation, 2025
- 288,136
MWh - Fuel burned, 2025
- 983,122
MMBtu - Capacity factor, 2025
- 25.6
% - Heat rate, 2025
- Not stated
| Year | Net generation (MWh) | Fuel burned (MMBtu) | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|---|
| 2025 | 288,136 | 983,122 | 25.6% | — |
| 2024 | 188,164 | 642,014 | 16.7% | — |
| 2023 | 123,474 | 421,293 | 11.0% | — |
| 2022 | 210,821 | 719,323 | 18.7% | — |
| 2021 | 287,744 | 2,544,808 | 25.6% | — |
| 2020 | 337,870 | 2,962,107 | 30.0% | — |
| 2019 | 549,249 | 4,891,062 | 48.8% | — |
| 2018 | 176,311 | 1,605,136 | 15.7% | — |
| 2017 | 248,572 | 2,290,094 | 22.1% | — |
| 2016 | 251,699 | 2,323,686 | 22.3% | — |
| 2015 | 347,677 | 3,240,003 | 30.9% | — |
| 2014 | 111,265 | 1,058,132 | 9.9% | — |
| 2013 | 253,738 | 2,420,913 | 22.6% | — |
| 2012 | 95,618 | 918,380 | 8.5% | — |
| 2011 | 170,798 | 1,660,755 | 15.2% | — |
| 2010 | 277,762 | 2,709,845 | 24.7% | — |
| 2009 | 378,248 | 3,691,700 | 33.6% | — |
| 2008 | 403,128 | 3,972,423 | 35.7% | — |
| 2007 | 272,695 | 2,695,319 | 24.2% | — |
| 2006 | 39,643 | 393,220 | 3.5% | — |
| 2005 | 272,746 | 2,727,187 | 24.2% | — |
| 2004 | 287,962 | 2,885,955 | 25.5% | — |
| 2003 | 112,284 | 1,149,900 | 10.0% | — |
| 2002 | 150,897 | 1,535,075 | 13.4% | — |
| 2001 | 176,071 | 1,819,342 | 15.7% | — |
How these are worked out
Net generation and fuel burned are the monthly figures EIA publishes in its bulk electricity file, from the plant's Form 923 reports; a year is the sum of its months. Capacity factor is a full year's net generation over today's nameplate capacity times the hours in that year (8,784 in a leap year), so a plant uprated or partly retired since reads against its current size; heat rate is fuel burned over net generation, for plants that burn fuel. A year with fewer than twelve months stated has no capacity factor, and a value outside the plausible range is left blank rather than shown. By month, the charts apply the same rules to each month's own hours and fuel.
Sources
3 sourcesSources
- EIA-860M Preliminary Monthly Electric Generator Inventory
- Global Energy Monitor — Global Integrated Power Tracker (unit-level power plants, eight technologies, all statuses)Global Integrated Power Tracker, Global Energy Monitor, September 2026 release (https://globalenergymonitor.org/projects/global-integrated-power-tracker), CC BY 4.0. Modified by Inframation: TransitionZero-sourced rows removed; statuses and technologies mapped to Inframation's vocabulary; figures aggregated. Copyright © Global Energy Monitor. Global Integrated Power Tracker, September 2026 release. Distributed under a Creative Commons Attribution 4.0 International License.
- EIA Open Data bulk file — Electricity (ELEC.zip; monthly plant net generation and fuel consumption since 2001)Source: U.S. Energy Information Administration, Electricity bulk data (Form EIA-923 monthly plant series)