Greenwich Substation and Line Project

Eversource is proposing to construct a new 115-kilovolt (kV) bulk substation and two new 115-kV underground transmission lines in Greenwich, Conn.

The proposed Greenwich Substation and Line Project will extend approximately 2.3 miles between the existing Eversource substation on Sound Shore Drive in Cos Cob to the proposed new substation on Railroad Avenue.

The Project is needed to address increasing customer demand and to improve reliability of electric supply in Greenwich. The existing electric infrastructure serving Greenwich is expected to reach its maximum capacity in 2017 under certain operating conditions. By adding a new substation, Eversource will be able to meet the expected customer demand for approximately 30 years.

Keeping the lines of communication open is an important part of our work in your community. Regular updates will be made to this site, as appropriate.

Greenwich project map

Project Facts:

  • Route ​length: Approximately 2.3 miles
  • Location: Greenwich, Connecticut
  • Line ​voltage: Two 115,000-volt (115 kV) underground transmission lines
  • Substation: One new transmission-level substation
  • Siting ​review ​by: ​The Connecticut Siting Council (CSC)

Estimated Timetable:

  • ​​Municipal Consultation Filing (MCF): February 6, 2015
  • Public ​open ​houses: March 3 and July 15, 2015
  • Connecticut Siting Council (CSC) Application ​filing: June 26, 2015
  • CSC Public Hearing: September 1, 2015, 6:30 p.m., Greenwich Library, Cole Auditorium
  • CSC ​decision: ​First Quarter 2016
  • If ​approved, ​submit Development & Management Plan to CSC ​for ​approval: ​Second Quarter 2016
  • Start of ​construction (pending all necessary approvals): ​Fall 2016
  • Estimated ​in-​service ​date: ​Second Quarter 2018

Open Houses

During the Municipal Consultation Filing period in the spring of 2015, an open house was held on Tuesday, March 3, 2015, at the Greenwich Town Hall to give local residents and business owners an opportunity to learn more about the project, ask questions, and provide comments on the proposed project with subject matter experts from Eversource.

A second open house was held on Wednesday, July 15, 2015, at the Greenwich Town Hall. Eversource explained some new supported route variations designed as a result of community input received during the Municipal Consultation process, as well as the enhanced design for the new substation proposed for 290 Railroad Avenue.

Connecticut Siting Council (CSC) Application Filing and Municipal Consultation Process

Involving the public and municipal leaders is an important part of the Project’s planning process. For an electric transmission line project, such as the Greenwich Substation and Line Project, the Municipal Consultation and Application Filing phases are part of the siting review process, as defined by the Connecticut state statutes.

The statutes require that an applicant for a new electric transmission line provide certain information on the proposed project to Connecticut municipal officials in communities affected by the proposed transmission route, and to seek input from each town before the filing of an application. To learn more about the siting process, visit the Connecticut Siting Council (CSC) website.

CSC Application

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. The Application describes the site and features of the proposed Greenwich Substation, along with the required modifications of the Cos Cob Substation.

The Application also includes a description of the Preferred Route and alternate routes considered for the transmission lines, along with an evaluation of the environmental, engineering, reliability, operability, and cost considerations associated with those routes.

Municipal Consultation Filing

The Municipal Consultation Filing (MCF) was submitted to the Town of Greenwich on February 6, 2015. The MCF provides information concerning the public need, site selection process, maps, analyses of alternate sites/routes, schedule and environmental effects of the proposed Project.

In order to facilitate the MCF process, Eversource offers to meet with the chief elected and other officials of the affected municipality to explain the Project and provide information on the proposed Project route, including the route selection process and the environmental effects, among others.

Contact Information

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