Bear Swamp
Hydro power plant · Berkshire County, Massachusetts
Details
- Primary fuel
- Hydro
- Technology
- Hydroelectric Pumped Storage
- Operator
- Bear Swamp Power Company LLC
- County
- Berkshire County
- Generating units
- 2
- Share of state capacity
- 4.75%
- Rank among hydro plants in Massachusetts
- #2 of 32
- EIA plant code
- 8005
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| GEN1 | Hydroelectric Pumped Storage | 333 MW | 333 MW | 1974 | Operating |
| GEN2 | Hydroelectric Pumped Storage | 333 MW | 333 MW | 1974 | 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
| Vineyard Wind 1 | Wind | 800 MW |
| Salem Harbor Power Development LP | Natural gas | 798 MW |
| ANP Bellingham Energy Project | Natural gas | 578 MW |
| ANP Blackstone Energy Project | Natural gas | 578 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 666 MW solar plant and a 666 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