Millstone
Nuclear power plant in New London County, Connecticut. 2,259.9 MW of nameplate capacity across 2 generators, operated by Dominion Energy Nuclear Conn Inc.
Also known as Millstone Nuclear Power Plant · EIA plant 566
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 2,259.9 MWNameplate
- Generators
- 2 operatingEIA-860M, August 2026
- Operating since
- December 1975First generator online
- Operator
- Dominion Energy Nuclear Conn IncEIA operator ID 5221
- Grid
- ISO-NEBalancing authority ISNE
- Price nodes
- 2 ISONE nodesResource nodes with prices
- Location
- New London County, CT41.3107, −72.1677
- EIA plant ID
- 566EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Millstone produces
Free · EIA-923Net generation, 2025
16.7 TWh
16,708,717 MWh, final
Capacity factor, 2025
84.4%
2024: 85.0%
January to July 2026
9.73 TWh
Provisional
Range, 2015 to 2025
13.7–17.4
TWh a year. Low 2023, high 2015
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | 16,365,334 | Not reported | 12 of 12 |
| 2001 | 15,427,767 | Not reported | 12 of 12 |
| 2002 | 14,918,272 | Not reported | 12 of 12 |
| 2003 | 16,078,095 | Not reported | 12 of 12 |
| 2004 | 16,539,097 | Not reported | 12 of 12 |
| 2005 | 15,562,122 | Not reported | 12 of 12 |
| 2006 | 16,589,446 | Not reported | 12 of 12 |
| 2007 | 16,386,142 | Not reported | 12 of 12 |
| 2008 | 15,432,946 | Not reported | 12 of 12 |
| 2009 | 16,657,382 | Not reported | 12 of 12 |
| 2010 | 16,750,304 | 88.4% | 12 of 12 |
| 2011 | 15,927,837 | 84.1% | 12 of 12 |
| 2012 | 17,077,887 | 89.9% | 12 of 12 |
| 2013 | 17,079,582 | 90.1% | 12 of 12 |
| 2014 | 15,840,619 | 83.6% | 12 of 12 |
| 2015 | 17,410,917 | 91.9% | 12 of 12 |
| 2016 | 16,575,492 | 87.2% | 12 of 12 |
| 2017 | 16,499,621 | 87.1% | 12 of 12 |
| 2018 | 16,881,492 | 89.1% | 12 of 12 |
| 2019 | 16,733,398 | 88.3% | 12 of 12 |
| 2020 | 15,714,855 | 82.7% | 12 of 12 |
| 2021 | 17,216,509 | 90.9% | 12 of 12 |
| 2022 | 16,464,167 | Not reported | 12 of 12 |
| 2023 | 13,669,458 | Not reported | 12 of 12 |
| 2024 | 16,870,305 | 85.0% | 12 of 12 |
| 2025 | 16,708,717 | 84.4% | 12 of 12 |
| 2026 (provisional, partial year) | 9,727,358 | 84.6% | 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, USGSWithdrawal, 2024
698,012
million gallons
Consumption, 2024
0
million gallons
Source
Long Island Sound
Surface, Saline. Once-through
Watershed stress
Very low/none · 0.099
USGS SUI, HUC12 Fenger Brook-Frontal Long Island Sound
24 of 24 cooling months report withdrawal. Saline, brackish or ocean intake; not tested. Blank volumes are unreported, not zero.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 2 | Nuclear | 909.9 | December 1975 |
| 3 | Nuclear | 1,350.0 | April 1986 |
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 Dominion Energy Nuclear Conn Inc as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Generation potential vs reported
Monthly potential at seasonal net capability, next to EIA-923 output. Shows how much of the plant's capability was used.
300 analyst questions a month, plus MCP
Query Millstone and 14,224 other projects from Claude or your own tools. Free accounts get 1 question a day.
Power plants near Millstone
Questions about Millstone
How much power does Millstone produce?
Millstone reported 16,708,717 MWh (16.7 TWh) of net generation in 2025, a 84.4% capacity factor on 2,259.9 MW of nameplate capacity. From January to July 2026 it reported 9.73 TWh, which is provisional.
Where is Millstone?
Millstone is in New London County, Connecticut, at 41.3107, −72.1677. It is in the ISO New England Inc. balancing area (ISNE).
Who operates Millstone?
EIA-860M for August 2026 lists Dominion Energy Nuclear Conn Inc as the operator (EIA operator ID 5221). The operator is not always the owner.
When did Millstone start operating?
Its first generator began operating in December 1975, according to EIA-860M.
Does InfraMap have power prices for Millstone?
Yes. InfraMap has ISONE day-ahead and real-time prices at 2 price nodes linked to Millstone, 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
- EIA-923 cooling water 2024 and the USGS surface water supply and use index, Water years 2010-2020 (Oct 2009 to Sep 2020), mean of monthly values
- Plant names from OpenStreetMap, © OpenStreetMap contributors (ODbL)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page