Workshop of the World

stories of industry in & around Philadelphia

Willow Street Steam Plant (1927)
875 Willow Street (northeast corner 9th and Willow Streets), Philadelphia, PA

Harry Kyriakodis (2007)

Willow Street Steam Generation Plant-2
Detail, south and east facades.

Surrounded by numerous manhole covers with the word "STEAM" stamped on them is the Willow Street Steam Generation Plant. This great hulking structure was built in 1927 by the Philadelphia Electric Company as part of Center City Philadelphia's elaborate steam delivery system, which still operates. Rail cars used to bring fuel via tracks along Willow Street. The smokestacks are 163 feet high. It's been abandoned for over 25 years. The large interior spaces that held the boilers preclude easy alteration for reuse, as there are no floors inside the building. There have been proposals to convert the structure into a trash-to-steam plant and also to cover it with huge wrap-around advertising. It may be decades before anything happens with it. The asbestos-filled building has been sealed by the fire department, because it is so dangerous.

The roots of Philadelphia's district steam system dates back to 1889, when the Edison Electric Light Company of Philadelphia—which eventually became part of the Philadelphia Electric Company—began to generate and sell electricity from its central station at 908 Sansom Street. Later that year, exhaust steam from the plant's engines was used to warm a nearby house at 917 Walnut Street, creating an additional source of revenue. The Philadelphia Electric Company later built other steam generating plants, including the Willow Street Plant, and constructed a vast underground steam network to serve various buildings and institutions. The system became the third largest district steam heating system in the United States. Steam pipes in Philadelphia run under sidewalks rather than under streets, as in other places. The steam is sent under pressure at a constant temperature of about 450 degrees, summer and winter, enabling the pipes to last for decades with little wear.

Philladelphia's Steam Distribution System

PECO sold its steam system to Philadelphia Thermal Energy Corporation in 1987 for $30 million. In 1993, Trigen Energy Corporation purchased United Thermal Corporation, the parent company of Philadelphia Thermal Energy. Today, Trigen owns and operates the downtown steam system, which delivers stream via 33 miles of underground pipes to customers throughout Center City and West Philadelphia. Nearly 400 of the city's businesses, hospitals, universities, hotels and residential buildings use the steam for heating, cooling, hot water and so on.

Willow Street Steam Plant
West and south facades. Photo Steven A. Ives (2007).