Largest greenhouse-gas emitters in Connecticut

36 facilities in Connecticut reported 10,889,445 metric tons CO2e of direct emissions to the EPA for 2023, 0.5% of the national total for reporting direct emitters. Power Plants accounts for the most (84%). Largest first.

#	Facility	City	Sector	t CO2e
1	Lake Road Generating Company	Dayville	Power Plants	2,159,025
2	CPV Towantic Energy Center	Oxford	Power Plants	1,938,201
3	Milford Power Company LLC	Milford	Power Plants	1,425,973
4	Bridgeport Harbor Station	Bridgeport	Power Plants	1,067,502
5	KLEEN ENERGY SYSTEMS POWER PLANT	Middletown	Power Plants	1,014,344
6	Bridgeport Energy	Bridgeport	Power Plants	1,012,876
7	Wheelabrator Bridgeport L.P.	Bridgeport	Waste	309,543
8	KIMBERLY-CLARK TISSUE MILL	New Milford	Pulp and Paper	139,055
9	Middletown	Middletown	Power Plants	132,892
10	SOUTHEASTERN CT RESOURCE RECOVERY FACILITY	Preston	Waste	103,873
11	YALE UNIVERSITY - SCHOOL OF MEDICINE	New Haven	Other	98,781
12	YALE UNIVERSITY CENTRAL POWER PLANT	New Haven	Other	95,584
13	UNIVERSITY OF CONNECTICUT	Storrs Mansfield	Other	95,456
14	Pratt & Whitney, East Hartford	East Hartford	Power Plants	93,595
15	RAND-WHITNEY CONTAINERBOARD LP	Montville	Pulp and Paper	92,177
16	Wallingford Energy, LLC	Wallingford	Power Plants	91,363
17	Pfizer	Groton	Other	88,454
18	Algonquin Power Windsor Locks, LLC	Windsor Locks	Power Plants	87,638
19	COVANTA BRISTOL, INC	Bristol	Waste	85,036
20	MANCHESTER LANDFILL	Manchester	Waste	80,880
21	Wheelabrator Lisbon Inc.	Lisbon	Waste	75,615
22	Cromwell	Cromwell	Petroleum and Natural Gas Systems	67,980
23	Oxford Station	Oxford	Petroleum and Natural Gas Systems	55,953
24	SIKORSKY AIRCRAFT HEADQUARTERS	Stratford	Other	52,376
25	IROQUOIS GAS TRANSMISSION SYSTEM, L.P. - BROOKFIELD COMPRESSOR STATION	Brookfield	Petroleum and Natural Gas Systems	50,539
26	Chaplin Station	Chaplin	Petroleum and Natural Gas Systems	50,426
27	FRITO-LAY	Killingly (dayville)	Other	40,905
28	Hartford Hospital Cogeneration Facility	Hartford	Power Plants	39,791
29	Montville	Uncasville	Power Plants	38,782
30	Naval Submarine Base New London	Groton	Other	33,690
31	PRATT & WHITNEY MIDDLETOWN	Middletown	Other	31,814
32	Hartford Steam - Columbus Plant	Hartford	Power Plants	31,798
33	Hamilton Sundstrand Corporation	Windsor Locks	Other	29,237
34	New Haven Harbor Station	New Haven	Power Plants	28,841
35	Mohegan Tribe of Indians of Connecticut	Uncasville	Other	28,085
36	Waterbury Generation	Waterbury	Power Plants	21,363

Source: EPA Greenhouse Gas Reporting Program, 2023 reporting year, sector-level emissions from data.epa.gov (fetched October 31, 2026). Direct emissions in metric tons CO2e as EPA totals them: emitter sectors only, biogenic CO2 reported separately. Covers facilities that report as direct emitters; most emit 25,000 t CO2e or more a year. Reference only.

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