Power plants in Connecticut
Connecticut has 182 power plants of 1 MW or more in the 2025 EIA-860 data, with 11.0 GW of nameplate capacity, the 39th-largest total among the 50 states and DC. Natural gas accounts for 49% of that capacity. The biggest single site is Millstone at 2,260 MW. Units that came online from 2020 to 2025 add 406 MW, led by solar at 87%. Units retired since 2016 at plants still operating total 419 MW, most of it coal.
- Natural gas5,388 MW49%
- Oil and petroleum2,532 MW23%
- Nuclear2,260 MW21%
- Solar493 MW4.5%
- Biomass and waste161 MW1.5%
- Hydroelectric118 MW1.1%
- Pumped-storage hydro31 MW0.3%
- Wind5 MW0.0%
- Battery storage1.6 MW0.0%
What is running, by the decade it came online
NuclearNatural gasOil and petroleumHydroelectricPumped-storage hydroWindSolarBattery storageBiomass and waste
Columns above the line show capacity still operating in 2025, stacked by fuel. Below the line: capacity retired in each decade at plants that still operate.
The 25 largest plants
| Rank | Plant | Runs on | Capacity | First unit | Operator |
|---|---|---|---|---|---|
| 1 | Millstone | Nuclear | 2,260 MW | 1975 | Dominion Energy Nuclear Conn Inc |
| 2 | CPV Towantic Energy Center | Natural gas | 842 MW | 2018 | CPV Towantic, LLC |
| 3 | Lake Road Generating Plant | Natural gas | 840 MW | 2002 | Lake Road Generating Co LP |
| 4 | Middletown | Oil and petroleum | 786 MW | 1958 | Middletown Power LLC |
| 5 | Kleen Energy Systems | Natural gas | 693 MW | 2011 | Kleen Energy Systems, LLC |
| 6 | New Haven Steam | Oil and petroleum | 642 MW | 1975 | Generation Bridge II Connecticut, LLC |
| 7 | Milford Power Project | Natural gas | 578 MW | 2004 | Milford Power Co LLC |
| 8 | Bridgeport Station | Natural gas | 576 MW | 2019 | Generation Bridge II Connecticut, LLC |
| 9 | Bridgeport Energy Project | Natural gas | 520 MW | 1998 | Bridgeport Energy LLC |
| 10 | Montville Station | Oil and petroleum | 495 MW | 1954 | Montville Power LLC |
| 11 | Wallingford Energy | Natural gas | 350 MW | 2001 | Wallingford Energy LLC |
| 12 | GenConn Devon LLC | Oil and petroleum | 242 MW | 2010 | GenConn Devon LLC |
| 13 | GenConn Middletown LLC | Oil and petroleum | 242 MW | 2011 | GenConn Middletown LLC |
| 14 | Devon Station | Oil and petroleum | 223 MW | 1985 | Devon Power LLC |
| 15 | Gravel Pit Solar, LLC | Solar | 120 MW | 2025 | Gravel Pit Solar, LLC |
| 16 | Cos Cob | Oil and petroleum | 115 MW | 1969 | Connecticut Jet Power LLC |
| 17 | Waterbury Generation | Natural gas | 96 MW | 2009 | Engie North America |
| 18 | A L Pierce | Natural gas | 84 MW | 2007 | MPH AL Pierce, LLC |
| 19 | Algonquin Windsor Locks | Natural gas | 71 MW | 1990 | Ahlstrom Power Windsor Locks LLC |
| 20 | Waterside Power, LLC | Oil and petroleum | 69.6 MW | 2004 | Waterside Power, LLC |
| 21 | Wheelabrator Bridgeport | Biomass and waste | 67 MW | 1988 | Wheelabrator Environmental Systems |
| 22 | Quinebaug Solar | Solar | 49.4 MW | 2021 | Quinebaug Solar, LLC |
| 23 | Plainfield Renewable Energy LLC | Biomass and waste | 43 MW | 2013 | Plainfield Renewable Energy, LLC |
| 24 | Pfizer Groton Plant | Natural gas | 37.5 MW | 1952 | Pfizer Inc |
| 25 | Shepaug | Hydroelectric | 37.2 MW | 1955 | FirstLight Power Resources Services LLC |
Largest plant for each main fuel
| Main fuel | Plants | Capacity | Largest plant | Its capacity |
|---|---|---|---|---|
| Natural gas | 47 | 4,961 MW | CPV Towantic Energy Center | 842 MW |
| Oil and petroleum | 23 | 2,964 MW | Middletown | 786 MW |
| Nuclear | 1 | 2,260 MW | Millstone | 2,260 MW |
| Solar | 90 | 492 MW | Gravel Pit Solar, LLC | 120 MW |
| Biomass and waste | 6 | 161 MW | Wheelabrator Bridgeport | 67 MW |
| Hydroelectric | 13 | 116 MW | Shepaug | 37.2 MW |
| Pumped-storage hydro | 1 | 31 MW | Rocky River (CT) | 31 MW |
| Wind | 1 | 5 MW | Wind Colebrook South | 5 MW |
Balancing areas
| Area | Plants | Capacity |
|---|---|---|
| ISO New England | 182 | 11.0 GW |
Biggest operators here
| Operator | Plants | Capacity |
|---|---|---|
| Dominion Energy Nuclear Conn Inc | 1 | 2,260 MW |
| Generation Bridge II Connecticut, LLC | 2 | 1,218 MW |
| CPV Towantic, LLC | 1 | 842 MW |
| Lake Road Generating Co LP | 1 | 840 MW |
| Middletown Power LLC | 1 | 786 MW |
| Kleen Energy Systems, LLC | 1 | 693 MW |
| Milford Power Co LLC | 1 | 578 MW |
| Bridgeport Energy LLC | 1 | 520 MW |
| Montville Power LLC | 1 | 495 MW |
| Wallingford Energy LLC | 1 | 350 MW |