Registry, engineering, and operating metrics shown on a consistent EIA basis.
| Metric | Perryman Harford County | Essential Power Rock Springs LLC Cecil County |
|---|---|---|
| Capacity | 492.3 MW | 795.6 MW |
| Technology | Petroleum Liquids, Natural Gas Fired Combustion Turbine | Natural Gas Fired Combustion Turbine |
| Operator | Constellation Power Source Generation, LLC | Essential Power Operating Services LLC |
| Operating units | 6 | 4 |
| Latest 12-month generation | 342.5 GWh | 179.0 GWh |
| Latest complete-year capacity factor | 5.8% (2025) | 2.6% (2024) |
| National technology rank | #167 of 825 | #29 of 825 |
| Latest EIA report | 2026-04 | 2024-12 |
Generation comes from EIA-923. Capacity, unit counts, technology, and reporting relationships come from EIA-860. Incomplete reporting years are excluded from capacity-factor comparisons.