AOC, Capitol Power Plant
Architect of the CapitolDistrict of Columbia County
Capitol Power Plant is a natural gas-fired combustion turbine facility with 7.5 MW of nameplate capacity in the District of Columbia. It is owned and operated by the Architect of the Capitol, the federal legislative-branch agency responsible for the U.S. Capitol campus. The plant has supplied steam and chilled water to the U.S. Capitol, the Supreme Court, the Library of Congress and roughly twenty other buildings on Capitol Hill since December 1910, though it stopped generating grid electricity for the complex in 1951. Between 2009 and the early 2010s the plant phased out coal in favor of natural gas as its primary fuel. In 2018 it commissioned a 7.5 MW natural-gas cogeneration (combined heat and power) unit, a $57 million project built for a 20-year payback that lifted the plant's combined efficiency to roughly 75%. No whole-plant or unit retirement is scheduled; the single gas turbine, CTG1, that came online in August 2018 remains the plant's only generator today.
Mapped infrastructure geometry associated with this asset.
EIA plant 63347 · Inventory for Sep 2026.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| CTG1 | Natural Gas Fired Combustion Turbine | Operating | 7.5 | Unknown |
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Current generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| CTG1 | 7.5 MW 7.5 MW summer | Natural Gas Fired Combustion Turbine GT | Aug 2018 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Where the plant sits in PJM: its market, pricing node, utility territory and the network around it, each with how it is known.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
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Project milestones and public references behind the asset profile.
DOEE issued Permit 6663-C and Permit 6664-C in combination for two proposed cogeneration systems. The second system was never constructed.
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
EIA-860 lists generator CTG1 with this operating date.
DOEE issued technical support memorandum for renewal of Permit 6663-R1, confirming operation of the single 7.5-MW combustion turbine and noting that the second proposed cogeneration system was not constructed.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
AOC, Capitol Power Plant reports 7.5 MW natural gas of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Sep 2026.
AOC, Capitol Power Plant is a Natural Gas Fired Combustion Turbine facility in District of Columbia County, DC, participating in the PJM market.
AOC, Capitol Power Plant is in District of Columbia County, DC, inside the PJM balancing area.
AOC, Capitol Power Plant is operated by Architect of the Capitol, Capitol Power Plant according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
AOC, Capitol Power Plant reported 54.5 GWh over the twelve months to 2024-12. Figures are net generation as filed to EIA-923.
By capacity, AOC, Capitol Power Plant ranks #729 of 829 operating plants of the same technology nationally. It ranks #2 of 3 in DC.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.