Northfield Mountain
Hydro power plant · Franklin County, Massachusetts
Details
- Primary fuel
- Hydro
- Technology
- Hydroelectric Pumped Storage
- Operator
- FirstLight Power Resources, Inc. - MA
- County
- Franklin County
- Generating units
- 4
- Share of state capacity
- 8.32%
- Rank among hydro plants in Massachusetts
- #1 of 32
- EIA plant code
- 547
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| 1 | Hydroelectric Pumped Storage | 292 MW | 292 MW | 1973 | Operating |
| 2 | Hydroelectric Pumped Storage | 292 MW | 292 MW | 1973 | Operating |
| 3 | Hydroelectric Pumped Storage | 292 MW | 292 MW | 1973 | Operating |
| 4 | Hydroelectric Pumped Storage | 292 MW | 292 MW | 1972 | 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 Massachusetts
| Canal | Other | 1,495 MW |
| Fore River Generating Station | Natural gas | 872 MW |
| Vineyard Wind 1 | Wind | 800 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 1,168 MW solar plant and a 1,168 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 Massachusetts power plants · What Massachusetts actually generates