Somersworth Lower Great Dam — renewablesinfo.org

Somersworth Lower Great Dam — Plant Summary

EIA Plant ID: 50704
Capacity: 1.3 MW
Primary Fuel: Hydro
Technology: Conventional Hydroelectric
Status: Operating
Location: Strafford, NH
Operating Since: 1985
Generators: 1
Operator: Green Mountain Power Corp
Parent Company: small shareholder(s)
Annual Generation: 1,331 MWh
Capacity Factor: 11.7%
Balancing Authority: ISO New England Inc.
ISO/RTO: ISONE
NERC Region: NPCC

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Somersworth Lower Great Dam

OperatingHydro

Ranked #28 of 32 Hydro plants in NH#1362 of 1454 nationally

1.3 MW Hydro operating in Strafford, NH — ISO New England Inc.

EIAWD

1.3 MW

Nameplate Capacity

Generators

unit

Conventional Hydroelectric

Technology

1985

Operating Since

Location

Coordinates

43.2511, -70.8408

County

Strafford, NH

Nearby Plants

Rollinsford
Hydro1.4 MW · 2.5 km
Salmon Falls
Hydro1.2 MW · 3.6 km
Turnkey Landfill Gas Recovery
Landfill Gas9.2 MW · 10.3 km

Ownership & Operator

Field	EIA	GEM	Wikidata
Operator	Green Mountain Power Corp	Green Mountain Power	—
Owner(s)	Green Mountain Power Corp	small shareholder(s)	—
Status	Operating	—	—

Ownership Chain

About

The Somersworth Lower Great Dam is a hydroelectric power plant located in Strafford County, New Hampshire. The plant has a total capacity of 1.3 MW and consists of a single generator utilizing conventional hydroelectric technology. It began operating in 1985 and is owned by a group of small shareholders. Green Mountain Power Corp is the listed operator per EIA data.

The plant's latest annual generation was 1,331 MWh, resulting in a capacity factor of 11.7%. Somersworth Lower Great Dam operates within the ISO New England Inc. balancing authority and the Northeast Power Coordinating Council (NPCC) NERC region. In terms of size, the plant ranks 28th out of 32 power plants in New Hampshire and 1364th out of 1464 nationally.

Generated from EIA, GEM, and public data sources

EIA Plant Profile Wikidata

Engineering & Generators

Grid Context

NERC Region

NPCC

Balancing Authority

ISO New England Inc.

Grid Voltage

41.6 kV

Regulatory Status

Entity Type

Investor-Owned Utility

Sector

Electric Utility

Generation

0 MWh

Latest Month

1.3K MWh

Annual Generation

11.7%

Capacity Factor

Jan 2022 – Dec 2024

Financial Data

No financial data available for this plant.

Pricing & Market Data

MEDIUM confidence

Market Position

ISO/RTO Market

ISO-NE

LMP Node

—

Pricing Hub

.Z.NEWHAMPSHIRE

Node Source

OSM spatial match

News & Articles (9)Beta

Regulatory·permitting

Green Mountain Power Corporation; Notice of Application Ready for Environmental Analysis and Soliciting Comments, Recommendations, Terms and Conditions, and Prescriptions

Federal Register (FERC)·1 weeks ago

Regulatory·permitting

Green Mountain Power Corporation; Notice of Application Ready for Environmental Analysis and Soliciting Comments, Recommendations, Terms and Conditions, and Prescriptions

Federal Register (FERC)·1 weeks ago

General

Green Mountain Power seeks to install up to 1,200 storage batteries in remote homes

The state's largest electric utility is asking state regulators to approve a new tariff for all its ratepayers that would fund a project to...

Vermont Public·9 months ago

General

Green Mountain Power seeks to install up to 1,200 storage batteries in remote homes

The state's largest electric utility is asking state regulators to approve a new tariff for all its ratepayers that would fund a project to...

Vermont Public·9 months ago

Last updated 2026-03-25

View all 9 articles

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EIA Wikidata