73rd largest plant in Oklahoma · 2125th nationally
Markham is a hydroelectric power plant in Oklahoma with a nameplate capacity of 128 MW. It generates roughly 123.5k MWh per year — enough to power about 11,759 average U.S. homes.
Its capacity factor of 11% reflects intermittent or peaking operation.
| Plant Name | Markham |
|---|---|
| Operator | Grand River Dam Authority |
| City | Locust Grove |
| County | Mayes County |
| State | Oklahoma |
| ZIP | 74352 |
| Coordinates | 36.23170, -95.18220 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| 1 | Conventional Hydroelectric | Water | 32.1 MW | Operating | 1964 |
| 2 | Conventional Hydroelectric | Water | 32.1 MW | Operating | 1964 |
| 3 | Conventional Hydroelectric | Water | 32.1 MW | Operating | 1964 |
| 4 | Conventional Hydroelectric | Water | 32.1 MW | Operating | 1964 |
| NERC Region | MRO |
|---|---|
| Balancing Authority | Southwest Power Pool |
Hydroelectric plants spin turbines using falling or flowing water — typically from a dam-impounded reservoir. They are dispatchable, long-lived, and emission-free at the point of generation, though large reservoirs can disrupt rivers and ecosystems and methane can be released from flooded vegetation.