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530.8 MW Hydro operating in Harford, MD — PJM Interconnection, LLC
530.8 MW
Nameplate Capacity
11
Generators
units
Conventional Hydroelectric
Technology
1928
Operating Since
Coordinates
39.6572, -76.1752
County
Harford, MD
Nearby Plants
Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Constellation Power, Inc | Constellation Energy | — |
| Owner(s) | Constellation Power, Inc | Constellation Energy | — |
| Status | Operating | operating | — |
The Conowingo Dam is a large hydroelectric dam in the lower Susquehanna River near the town of Conowingo, Maryland. The medium-height, masonry gravity dam is one of the largest non-federal hydroelectric dams in the U.S., and the largest dam in the state of Maryland. The dam sits about 9.9 miles (16 km) from the river mouth at Chesapeake Bay, 5 miles (8 km) south of the Pennsylvania border and 45 miles (72 km) northeast of Baltimore, on the border between Cecil and Harford counties. The dam is privately owned by the Susquehanna Electric Company, a subsidiary of Constellation Energy.
Read more on WikipediaConowingo is a 530.8 MW hydroelectric power plant located in Harford County, Maryland. It began operating in 1928 and utilizes conventional hydroelectric technology. The plant is owned by Constellation Energy and operated by Constellation Power, Inc. It consists of 11 generators and uses water (WAT) as its primary fuel source.
In the most recent year with available data, Conowingo generated 1,548,934 MWh of electricity, achieving a capacity factor of 33.3%. The plant is the largest of its kind in Maryland and ranks 47th out of 194 hydroelectric facilities nationally. The plant's balancing authority is PJM Interconnection, LLC, and it resides within the RFC NERC region.
Generated from EIA, GEM, and public data sources
ISO/RTO
PJM
Market
ISO/RTO Member
NERC Region
RFC
Balancing Authority
83.5K MWh
Latest Month
1.5M MWh
Annual Generation
33.3%
Capacity Factor
2013
$2,294/kW
Est. Construction Cost
Total estimated cost: $1.2B
Point of Interconnection
Nearest Substation
Conowingo
Substation Distance
< 10 km
Coord Source
OSM spatial
Market Position
ISO/RTO Market
PJM
LMP Node
CONOWING13 KV G10
Pricing Hub
WESTERN HUB
Location Type
Generation Node
Node Source
EIA-860 direct report
Last updated 2026-04-09
View all 10 articlesNo ask pi reports yet for this entity.
ask pi about ConowingoPJM Interconnection, LLC (PJM)
Grid Voltage
220.0 kV
Regulatory Status
NR — Non-Regulated
Entity Type
Independent Power Producer
Sector
IPP Non-CHP