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Greenwich Substation and Line Project

In October 2020, Eversource completed construction of its new Greenwich Substation, associated underground transmission lines, and modifications to its Cos Cob Substation.


As part of always working to serve you better, Eversource constructed two, new 115-kilovolt (kV) electric lines and built a new substation to improve reliability in Greenwich, Connecticut.

The new transmission lines extend 2.3 miles from Eversource’s existing Cos Cob Substation on Sound Shore Drive to the new Greenwich Substation at 290 Railroad Avenue. The lines run underground, primarily under town streets, including those in Bruce Park. Eversource constructed a pedestrian bridge in Bruce Park to carry the lines over Davis Mill Pond.

The project also included modifications to the Cos Cob Substation located at 12 Sound Shore Drive.

Greenwich project map

Click to enlarge map

Project Facts:

  • Underground route length: 2.3 miles
  • Location: Greenwich, Connecticut
  • Line voltage: 115,000-volt (115-kV) transmission line
  • Substation: One new transmission-level substation and modifications to the existing Cos Cob Substation
  • Siting review by: The Connecticut Siting Council (CSC)
  • Application filing to the CSC: June 26, 2015
  • CSC Decision issued: November 9, 2017
  • Cos Cob Substation start of modifications: May 12, 2018
  • Start of preparation for warehouse building demolition and pre-construction site preparation for Greenwich Substation: September 12, 2018
  • Start of construction for the new underground transmission lines: April 1, 2019
  • Start of warehouse building demolition for Greenwich Substation: April 1, 2019
  • Start of construction of the new Greenwich Substation: July 29, 2019
  • Project completion and energization: October 2020
  • Project restoration completion: Year-end 2020


Beginning with municipal briefings and other community outreach efforts, Eversource engages the community throughout the lifecycle of a project to provide information, answer questions and listen to concerns.

Eversource is committed to updating neighbors, businesses, and the Greenwich community about project activities in the area. 



For more information about the Greenwich Substation and Line Project, please email or call 800-793-2202.