Northfield Mountain
Pumped storage power plant in Franklin County, Massachusetts. 1,168 MW of nameplate capacity across 4 generators, operated by FirstLight Power Resources, Inc. - MA.
Also known as EIA plant 547
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 1,168 MWNameplate
- Generators
- 4 operatingEIA-860M, August 2026
- Operating since
- November 1972First generator online
- Operator
- FirstLight Power Resources, Inc. - MAEIA operator ID 58185
- Grid
- ISO-NEBalancing authority ISNE
- Price nodes
- 4 ISONE nodesResource nodes with prices
- Location
- Franklin County, MA42.6107, −72.4716
- EIA plant ID
- 547EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Northfield Mountain produces
Free · EIA-923Net generation, 2025
−285 GWh
−284,601 MWh, final
Capacity factor, 2025
Not reported
2024: Not reported
January to July 2026
−172 GWh
Provisional
Range, 2015 to 2025
−349.1–−181.1
GWh a year. Low 2016, high 2023
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | −528,904 | Not reported | 12 of 12 |
| 2001 | −552,245 | Not reported | 12 of 12 |
| 2002 | −512,425 | Not reported | 12 of 12 |
| 2003 | −392,991 | Not reported | 12 of 12 |
| 2004 | −386,698 | Not reported | 12 of 12 |
| 2005 | −329,032 | Not reported | 12 of 12 |
| 2006 | −371,347 | Not reported | 12 of 12 |
| 2007 | −579,880 | Not reported | 12 of 12 |
| 2008 | −460,041 | Not reported | 12 of 12 |
| 2009 | −370,828 | Not reported | 12 of 12 |
| 2010 | −156,114 | Not reported | 12 of 12 |
| 2011 | −296,643 | Not reported | 12 of 12 |
| 2012 | −206,679 | Not reported | 12 of 12 |
| 2013 | −222,347 | Not reported | 12 of 12 |
| 2014 | −309,676 | Not reported | 12 of 12 |
| 2015 | −313,833 | Not reported | 12 of 12 |
| 2016 | −349,056 | Not reported | 12 of 12 |
| 2017 | −339,776 | Not reported | 12 of 12 |
| 2018 | −292,747 | Not reported | 12 of 12 |
| 2019 | −272,637 | Not reported | 12 of 12 |
| 2020 | −262,172 | Not reported | 12 of 12 |
| 2021 | −273,523 | Not reported | 12 of 12 |
| 2022 | −270,305 | Not reported | 12 of 12 |
| 2023 | −181,121 | Not reported | 12 of 12 |
| 2024 | −270,876 | Not reported | 12 of 12 |
| 2025 | −284,601 | Not reported | 12 of 12 |
| 2026 (provisional, partial year) | −172,153 | Not reported | 7 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free account · ISONEEmissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 1 | Hydroelectric Pumped Storage | 292.0 | February 1973 |
| 2 | Hydroelectric Pumped Storage | 292.0 | October 1973 |
| 3 | Hydroelectric Pumped Storage | 292.0 | July 1973 |
| 4 | Hydroelectric Pumped Storage | 292.0 | November 1972 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists FirstLight Power Resources, Inc. - MA as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
300 analyst questions a month, plus MCP
Query Northfield Mountain and 14,224 other projects from Claude or your own tools. Free accounts get 1 question a day.
Power plants near Northfield Mountain
More plants operated by FirstLight Power Resources, Inc. - MA
Questions about Northfield Mountain
How much power does Northfield Mountain produce?
Northfield Mountain reported −284,601 MWh (−285 GWh) of net generation in 2025. From January to July 2026 it reported −172 GWh, which is provisional.
Where is Northfield Mountain?
Northfield Mountain is in Franklin County, Massachusetts, at 42.6107, −72.4716. It is in the ISO New England Inc. balancing area (ISNE).
Who operates Northfield Mountain?
EIA-860M for August 2026 lists FirstLight Power Resources, Inc. - MA as the operator (EIA operator ID 58185). The operator is not always the owner.
When did Northfield Mountain start operating?
Its first generator began operating in November 1972, according to EIA-860M.
Does InfraMap have power prices for Northfield Mountain?
Yes. InfraMap has ISONE day-ahead and real-time prices at 4 price nodes linked to Northfield Mountain, with the hub price and node-to-hub basis. Prices are free with an InfraMap account; pricing node names are part of InfraMap Pro.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- ISONE day-ahead and real-time prices; node and hub assignments as of 2026-10-05
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page