In the 1970s, multiple combustion turbine units were installed in a simple cycle configuration to meet peak power demands.

[6] TransCanada later sold Ravenswood to LS Power/Helix Energy Solutions Group in a package deal also including the Ironwood, Ocean State and Kibby Wind facilities for a total price of US$2.1 Billion.

3, also known as Unit 30 or Big Allis, is a natural gas facility at Ravenswood Generating Station owned by LS Power and operated by IHI Corporation Energy Services.

This sheer scale helped the plant become popularly known as "Big Allis", due to Allis-Chalmers' role in construction.

It is located on the Ravenswood site, consisting of Units 1, 2, 3 and 4, as well as several small gas turbines (GTs), and an oil depot.

The site also includes a steam generation plant consisting of four Babcock & Wilcox boilers, owned and run by Con Edison.

[17][18] A 750MWe nuclear reactor was proposed in 1962, to begin operation on the site in 1970, but was cancelled in 1964 due to controversy and safety concerns.