Perryman has a reported capacity of 492.3 MW. Source: EIA Form 860.

What kind of plant is Perryman?

Perryman is a Natural Gas Fired Combustion Turbine, Petroleum Liquids facility in Harford County, MD, participating in the PJM market.

Where is Perryman located?

Perryman is in Harford County, MD, inside the PJM balancing area.

Who operates Perryman?

Perryman is operated by Constellation Power Source Generation, LLC according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Perryman generate?

Perryman reported 375.7 GWh over the twelve months to 2026-06. Figures are net generation as filed to EIA-923.

How does Perryman compare to other plants?

By capacity, Perryman ranks #167 of 825 operating plants of the same technology nationally. It ranks #3 of 8 in MD.

Perryman — 492 MW gas plant, Harford County, MD

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Perryman — 492 MW gas plant, Harford County, MD · Ask the Grid

Overview

Reported capacity: 492.3 MW
EIA-reported nameplate capacity; other nameplate and seasonal ratings may differ.
Technology: Natural Gas Fired Combustion Turbine, Petroleum Liquids
Primary generation technology.
Registry anchor: Plant 1556
Constellation Power Source Generation, LLC · Harford County · PJM
Operating status: Operating
Perryman is currently operating; a closure or retirement is listed for February 1, 2016.

Profile

Operating status: Perryman is currently operating; a closure or retirement is listed for February 1, 2016.
Grid role: Peaking and flexible generation used to provide power during periods of high demand.
Context: Perryman serves as a flexible peaking facility in the PJM market. Its 2014–2015 Unit 6 expansion used two dual-fuel Pratt & Whitney FT4000 turbines connected to one generator; the mechanical contractor described the arrangement as a first-of-its-kind Pratt & Whitney design for that size range.
Physical build: The documented 120-MW Perryman expansion installed two dual-fuel Pratt & Whitney FT4000 turbines in simple-cycle configuration, rated at 60 MW each, with one shared generator, a 2-into-1 stack and SCR, balance-of-plant equipment, and mechanical piping. The Maryland permit identifies three identical Westinghouse model 501 simple-cycle combustion turbines burning distillate oil.

Structured profile

Reported capacity: 492.3 MW
Natural Gas Fired Combustion Turbine, Petroleum Liquids
Operating status: operating
Perryman is currently operating; a closure or retirement is listed for February 1, 2016.
Retirement: February 1, 2016
Perryman is currently operating; a closure or retirement is listed for February 1, 2016.
Location: Harford County
PJM
Operator

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Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
GT1	53.1 MW 52 MW summer	Petroleum Liquids Disillate Fuel Oil · GT	Jan 1972	Operating
GT2	53.1 MW 51 MW summer	Petroleum Liquids Disillate Fuel Oil · GT	Apr 1972 Retirement: Feb 2016	Operating
GT3	53.1 MW 51 MW summer	Petroleum Liquids Disillate Fuel Oil · GT	Apr 1972	Operating
GT4	53.1 MW 52 MW summer	Petroleum Liquids Disillate Fuel Oil · GT	Apr 1972	Operating
GT5

Performance

Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.

Peer context

Technology capacity: 333 MW; Natural Gas Fired Combustion Turbine
National rank: #167; of 825 operating peers
MD rank: #3; of 8 operating peers

Monthly generation

Download CSV

Latest 12 months

375.7 GWh

Reported net generation

Latest report

Jun 2026

EIA-923 monthly filing

2025 capacity factor

5.8%

Using current reported nameplate capacity

Grid and market context

Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.

Nearby substations

HIFLD infrastructure inventory

UNKNOWN139182

IN SERVICE · 115 kV

0.1 km

UNKNOWN123011

Commercial, land, and environmental record

Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.

Land and environmental record

Air Permit Identifier

Jul 16, 2024

Maryland Part 70 Operating Permit No. 24-025-0024

MDE's Part 70 permit list shows Constellation Perryman Permit No. 025-0024, issued July 16, 2024, expiring October 31, 2028, for Perryman Generating Station at 900 Chelsea Road.

Constellation Perryman 2024 IssuedT5 Permit

Air-Compliance Enforcement—NOx Violation

Apr 30, 2008

$19,000 penalty settled April 30, 2008

MDE reported that Constellation paid a $19,000 penalty resolving NOx emission standard violations at Perryman. CEM data showed one combustion turbine exceeded its limit on four days.

MDE Issues 5 Air Management Enforcement Actions

Air-Compliance Enforcement—Particulate Matter Violation

Apr 12, 2021

$12,500 penalty settled April 12, 2021

MDE finalized settlement with Perryman over alleged particulate-matter emissions-test failure. Station retested and returned to compliance; paid $12,500 settlement penalty.

enf_comp_2021_2

Groundwater Source And Withdrawal

2022

Talbot Aquifer; approximately 0.080 million gallons per day (2022)

Maryland PPRP identifies Perryman's groundwater source as the Talbot Aquifer with a 2022 withdrawal rate of approximately 0.080 mgd and a current appropriation limit of approximately 0.1 mgd.

Surface Water and Groundwater (CH5.2) Oct 2024

Site Acreage

May 18, 2022

704 acres

The Maryland Power Plant Research Program reports that Perryman facility occupies 704 acres including a 20 MW solar farm, natural-gas pipeline, substation, transmission lines, undeveloped farmland, and wooded areas.

9677 Perryman Reliability Modification fact sheet

Related parties and identifiers

Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.

Relationship graph

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AssetOwner / operatorContractorEquipment

Timeline and sources

Project milestones and public references behind the asset profile.

Project timeline

Jan 1972
Jan 1972
Generator enters operationEIA-860
EIA-860 lists generator GT1 with this operating date.
Apr 1972
Apr 1972
Generators enter operation

Reporting portfolio

EIA reporting entity

Constellation Power Source Generation, LLC

Entity 4161

Operating portfolio

2 plants

1 states

Reported capacity

575.1 MW

Natural Gas Fired Combustion Turbine · Petroleum Liquids

Largest reported plants in this portfolio
Largest reported plants	Capacity	State
PerrymanCurrent	492.3 MW	MD
Philadelphia	82.8 MW	MD

Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.

View full reporting portfolio

Perryman