Somersworth Lower Great Dam
Hydro power plant · Strafford County, New Hampshire
Details
- Primary fuel
- Hydro
- Technology
- Conventional Hydroelectric
- Operator
- Green Mountain Power Corp
- County
- Strafford County
- Generating units
- 1
- Share of state capacity
- 0.03%
- Rank among hydro plants in New Hampshire
- #27 of 31
- EIA plant code
- 50704
Generating units
| Unit | Technology | Nameplate | Summer | Online | Status |
|---|---|---|---|---|---|
| GEN1 | Conventional Hydroelectric | 1.3 MW | 1.2 MW | 1985 | 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 New Hampshire
| Newfound Hydroelectric | Hydro | 1.4 MW |
| Rollinsford | Hydro | 1.4 MW |
| Hillsborough Hosiery | Hydro | 1.2 MW |
| Lochmere Hydroelectric Plant | Hydro | 1.2 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 1.3 MW solar plant and a 1.3 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 New Hampshire power plants · What New Hampshire actually generates