Nameplate capacity
531 MW
Rank in Maryland
#9
of 234 plants
In service since
1928
March 1928
Details
- Primary fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Operator
- Constellation Power, Inc
- County
- Harford County
- Generating units
- 11
- Share of state capacity
- 3.99%
- Rank among hydro plants in Maryland
- #1 of 2
- EIA plant code
- 1574
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| 10 | Conventional Hydroelectric | 56 MW | 56 MW | 1964 | Operating |
| 11 | Conventional Hydroelectric | 56 MW | 52 MW | 1964 | Operating |
| 8 | Conventional Hydroelectric | 56 MW | 57 MW | 1964 | Operating |
| 9 | Conventional Hydroelectric | 56 MW | 57 MW | 1964 | Operating |
| 3 | Conventional Hydroelectric | 48 MW | 42 MW | 1928 | Operating |
| 7 | Conventional Hydroelectric | 48 MW | 42 MW | 1928 | Operating |
| 4 | Conventional Hydroelectric | 48 MW | 42 MW | 1928 | Operating |
| 6 | Conventional Hydroelectric | 48 MW | 42 MW | 1928 | Operating |
| 1 | Conventional Hydroelectric | 45 MW | 41 MW | 1928 | Operating |
| 2 | Conventional Hydroelectric | 36 MW | 33 MW | 1928 | Operating |
| 5 | Conventional Hydroelectric | 36 MW | 33 MW | 1928 | Operating |
Nameplate is the maximum rated output; summer capacity is what the unit can reliably deliver on a hot day, which is typically lower.
Similarly sized plants in Maryland
| CPV St Charles Energy Center | Natural gas | 775 MW |
| Herbert A Wagner | Other | 774 MW |
| Perryman | Natural gas | 492 MW |
| Dickerson Power | Natural gas | 326 MW |
About this data
From EIA’s inventory of operable generators, May 2026 release. Capacity is nameplate — the maximum rated output of the equipment, not what the plant actually generates over a year, which depends on how often it runs. A 531 MW solar plant and a 531 MW nuclear plant have the same entry here and produce very different amounts of electricity.
“In service since” is the earliest in-service date among the units still listed, so a site rebuilt around newer equipment can read as younger than the site itself. All Maryland power plants · What Maryland actually generates