All Bostonians know the power plant on Kneeland St. is a fixture on the Boston skyline. Its one of the most prominent features as you come into downtown from the Southeast expressway (I-93) from the South and its been there for 80 years. The district steam system it serves is an example of the sustainability inherent in much of the pre-WWII American public infrastructure.
The Kneeland St. plant was constructed in the 1920s as part of a central steam system installed throughout downtown Boston. This system extends as far west as the Back Bay, as far south as the D Street Projects in Southie, throughout the financial district and waterfront, and as far north as MGH. The majority of the steam system was built out between the 1920s through the 1950s with only modest changes being made since. NStar's predecessor, the Boston Edison company, built the plant and operated it until 1987ish when it was sold to the Trigen Corporation. Trigen specialized in running district steam heating systems throughout the USA. After a series of transactions in the mid 2000s, Trigen came under the ownership of Veolia and was rebranded in 2011. You may notice the new Veolia sign on the south side of this power plant.
Calling this a power plant is a bit of a misnomer since it actually only produces steam. It has four boilers and can put out 1,275,000 lbs of steam per hour. Three of the units burn natural gas with some dual fuel capability for No. 6 oil (the low sulfur kind). One of the units burns No. 4 (or any mixture of No. 2 & 6) and therefore is likely only turned on when they really need it since oil is pricey these days. This is a year round facility and customers of the district heating system rely on it not only for steam heat in winter, but for hot water and air conditioning via adsorption chillers that use steam to make cold water. Below you'll find a picture of the plant as seen from the corner of Lincoln St. and Kneeland St. as it appears on Google Maps