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20.5 MW Conventional Hydroelectric (2 MW) + Petroleum Liquids (19 MW) operating in New London, CT — ISO New England Inc.
20.5 MW
Nameplate Capacity
3
Generators
units
Hybrid (2)
Technology
Conventional Hydroelectric + Petroleum Liquids
1919
Operating Since
Coordinates
41.5555, -72.0425
County
New London, CT
Nearby Plants
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | FirstLight Power Resources Services LLC | — | — |
| Owner(s) | FirstLight Hydro Generating Company | — | — |
| Status | Operating | — | — |
The Tunnel power plant, located in New London County, Connecticut, is a hybrid facility utilizing both conventional hydroelectric and petroleum liquid technologies. It has a total capacity of 20.5 MW distributed across 3 generators. The plant began operating in 1919 and is owned and operated by FirstLight Power Resources Services LLC. Tunnel is ranked as the 4th largest of 14 hydroelectric plants in Connecticut, and 480th nationally out of 1464 similar facilities.
Tunnel's primary fuel source is water (WAT). In the most recent year of reported data, the plant generated 7,722 MWh, resulting in a capacity factor of 4.3%. The plant operates within the ISO New England Inc. balancing authority and the Northeast Power Coordinating Council (NPCC) NERC region.
Generated from EIA, GEM, and public data sources
ISO/RTO
ISO-NE
Market
ISO/RTO Member
NERC Region
NPCC — Northeast Power Coordinating Council
Balancing Authority
329 MWh
Latest Month
7.7K MWh
Annual Generation
4.3%
Capacity Factor
CO₂ Intensity
0 lb/MWh
NOx
0.132 lb/MWh
SO₂
2013
$2,294/kW
Est. Construction Cost
Total estimated cost: $47.0M
Point of Interconnection
Nearest Substation
Tunnel Substation · 115 kV
Substation Distance
0.086 km
Operator
Eversource
Coord Source
OSM spatial
Market Position
ISO/RTO Market
ISO-NE
LMP Node
UN.TUNNEL 23 TUNN
Pricing Hub
.Z.CONNECTICUT
Location Type
NETWORK NODE
Node Source
Curated node match
Last updated 2026-03-26
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Grid Voltage
23.0 kV
Regulatory Status
NR — Non-Regulated
Entity Type
Independent Power Producer
Sector
IPP Non-CHP
0.000 lb/MWh
CH₄
0.002 lb/MWh
N₂O
0.000 lb/MWh
Capacity Factor
6.6%
Annual Net Gen
12 GWh
CO₂eq
0.147 lb/MWh
Subregion
NPCC New England