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Greenwich Substation and Line Project

Eversource's motion to reopen its application to build a new transmission line and substation in Greenwich was granted in May 2017.

Eversource and Greenwich officials have been working together over the past year to re-examine the proposed project’s need and scope to address the adequacy of the electric system serving the town of Greenwich.

In May 2017, the Connecticut Siting Council (CSC) voted to grant Eversource’s motion to reopen its application to build a new transmission line and substation in Greenwich.


After a thorough examination of a number of solution options and variations, Eversource filed a petition for reconsideration with the CSC in the second quarter of 2017. Currently in front of the CSC for consideration is an alternative, all-underground design option, favored by the town of Greenwich, that would run mostly underground within town streets and Bruce Park. The alternative solution also includes a new Greenwich Substation on Railroad Avenue. 

In addition, this project calls for modifications to equipment at the existing Cos Cob Substation.

 Greenwich Map May 10 2017

Click to enlarge

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)

Estimated Timetable:

  • Municipal Consultation Filing (MCF): February 6, 2015
  • Connecticut Siting Council (CSC) Application filing: June 26, 2015
  • CSC Denial without Prejudice: May 13, 2016
  • Petition to reopen CSC Docket: May 5, 2017
  • CSC Public Hearing: July 13, 2017
  • CSC Decision: Fourth Quarter 2017
  • Start of Construction (pending approval):Mid-2018


On June 26, 2015, Eversource applied to the CSC for a Certificate of Environmental Compatibility and Public Need (Application) for the construction of the Greenwich Substation and Line Project. On May 13, 2016, the CSC voted to deny the project without prejudice.

On May 25, 2017, the CSC granted Eversource's Petition to reopen Docket 416.


The CSC-sponsored public hearing was held on July 13, 2017, in Greenwich. The public hearing gave local residents, business owners and other stakeholders an opportunity to ask questions and provide comments on the proposed project. 


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