Kleen Energy Systems
Natural gas power plant in Middlesex County, Connecticut. 693 MW of nameplate capacity across 3 generators, operated by Kleen Energy Systems, LLC.
Also known as Kleen Energy · EIA plant 56798
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 693 MWNameplate
- Generators
- 3 operatingEIA-860M, August 2026
- Operating since
- July 2011First generator online
- Operator
- Kleen Energy Systems, LLCEIA operator ID 55993
- Grid
- ISO-NEBalancing authority ISNE
- Price nodes
- 1 ISONE nodeResource nodes with prices
- Location
- Middlesex County, CT41.5532, −72.5969
- EIA plant ID
- 56798EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Kleen Energy Systems produces
Free · EIA-923Net generation, 2025
3.22 TWh
3,216,190 MWh, final
Capacity factor, 2025
53.0%
2024: 47.8%
January to July 2026
2.19 TWh
Provisional
Range, 2016 to 2025
1.8–4.0
TWh a year. Low 2020, high 2016
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | Not reported | Not reported | 0 of 12 |
| 2002 | Not reported | Not reported | 0 of 12 |
| 2003 | Not reported | Not reported | 0 of 12 |
| 2004 | Not reported | Not reported | 0 of 12 |
| 2005 | Not reported | Not reported | 0 of 12 |
| 2006 | Not reported | Not reported | 0 of 12 |
| 2007 | Not reported | Not reported | 0 of 12 |
| 2008 | Not reported | Not reported | 0 of 12 |
| 2009 | Not reported | Not reported | 0 of 12 |
| 2010 | Not reported | Not reported | 0 of 12 |
| 2011 | 1,924,519 | Not reported | 6 of 12 |
| 2012 | 1,012,452 | 66.2% | 3 of 12 |
| 2013 | 3,242,663 | Not reported | 12 of 12 |
| 2014 | 3,323,204 | 54.7% | 12 of 12 |
| 2015 | 3,963,933 | 71.4% | 11 of 12 |
| 2016 | 4,005,807 | 65.8% | 12 of 12 |
| 2017 | 3,984,842 | Not reported | 12 of 12 |
| 2018 | 2,579,553 | Not reported | 12 of 12 |
| 2019 | 2,115,440 | 34.8% | 12 of 12 |
| 2020 | 1,766,365 | 29.0% | 12 of 12 |
| 2021 | 2,418,272 | 39.8% | 12 of 12 |
| 2022 | 2,416,228 | 39.8% | 12 of 12 |
| 2023 | 2,700,107 | 44.5% | 12 of 12 |
| 2024 | 2,912,514 | 47.8% | 12 of 12 |
| 2025 | 3,216,190 | 53.0% | 12 of 12 |
| 2026 (provisional, partial year) | 2,187,983 | 62.1% | 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 CAMPDCO₂, 2025
1.32M
US short tons. 2024: 1.19M
SO₂, 2025
7
US short tons
NOx, 2025
85
US short tons
CO₂ per MWh, calculated
0.41 t
About 821 lb per MWh
2 of 2 EPA units reported CO₂ in 2025 (U1, U2), matched to EIA plant 56798 through the EPA–EIA crosswalk. The per-MWh rate is EPA CO₂ divided by EIA-923 net generation. The two reporting boundaries can differ.
Water use
Free · EIA-923 cooling, USGSWithdrawal, 2024
551
million gallons
Consumption, 2024
485
million gallons
Source
Connecticut River
Surface, Fresh. Induced-draft tower
Watershed stress
Very low/none · 0.134
USGS SUI, HUC12 Mill Creek-Connecticut River
12 of 12 cooling months report withdrawal. SUI of the source river HUC12 within 3 km. Blank volumes are unreported, not zero.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| ST | Natural Gas Fired Combined Cycle | 295.0 | July 2011 |
| U1 | Natural Gas Fired Combined Cycle | 199.0 | July 2011 |
| U2 | Natural Gas Fired Combined Cycle | 199.0 | July 2011 |
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 Kleen Energy Systems, LLC 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.
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Questions about Kleen Energy Systems
How much power does Kleen Energy Systems produce?
Kleen Energy Systems reported 3,216,190 MWh (3.22 TWh) of net generation in 2025, a 53.0% capacity factor on 693 MW of nameplate capacity. From January to July 2026 it reported 2.19 TWh, which is provisional.
Where is Kleen Energy Systems?
Kleen Energy Systems is in Middlesex County, Connecticut, at 41.5532, −72.5969. It is in the ISO New England Inc. balancing area (ISNE).
Who operates Kleen Energy Systems?
EIA-860M for August 2026 lists Kleen Energy Systems, LLC as the operator (EIA operator ID 55993). The operator is not always the owner.
When did Kleen Energy Systems start operating?
Its first generator began operating in July 2011, according to EIA-860M.
Does InfraMap have power prices for Kleen Energy Systems?
Yes. InfraMap has ISONE day-ahead and real-time prices at 1 price node linked to Kleen Energy Systems, 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)
- EPA CAMPD annual emissions through the EPA–EIA crosswalk, 1995 to 2025
- 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