Stewards of the iconic buildings and grounds of Capitol Hill since 1793.

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The U.S. Capitol Rotunda is a large, domed, circular room located 96 feet in diameter and 180 feet in height located in the center of the United States Capitol on the second floor.
The U.S. Capitol Rotunda is a large, domed, circular room 96 feet in diameter...

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Snapshot of a crowd of people on a guided tour through the Rotunda of the U.S. Capitol
Official Tours of the U.S. Capitol Building are offered Monday through...

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AOC members holding the Historic Preservation Award that they received
The Architect of the Capitol strives to perform all work at a high level of...

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City of Trees book cover artwork
Enjoy the fall foliage that graces the U.S. Capitol Grounds on November 15 at...

Capitol Power Plant

Employees at the Capitol Power Plant working on a project

The AOC Capitol Power Plant jurisdiction (CPP) is responsible for managing and operating the Capitol Power Plant. The Power Plant operates 24 hours per day, 365 days per year to provide steam and chilled water service to heat and cool the Capitol, the Capitol Visitor Center and 22 other facilities located on or near Capitol Hill.

Commissioned in 1910, the Power Plant originally provided the Capitol with both steam and electricity. Today, the Power Plant provides steam and chilled water utility services to both congressional and non-congressional facilities, the latter of which is provided on a reimbursable basis.

The jurisdiction procures electricity from commercial suppliers. In addition to the central steam and refrigeration plants, the jurisdiction maintains an administration building and the tunnel distribution and metering systems required to deliver these utilities. The jurisdiction is responsible for the daily care, maintenance and operation of the Power Plant facilities. In addition, the CPP continues to implement operational changes and pursues modernization efforts to ensure the most cost effective and energy-efficient operations.