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Greenwich Substation and Line Project
Project Description

Project logoProject Description: Greenwich Substation and Line Project

Greenwich Map
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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 in Cos Cob to a new substation.

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. By adding a new substation, Eversource will be able to meet expected customer demand for approximately 30 years.

To learn more, see the customer bill insert, the Project brochure, and the short video (755 kbps, approx. 5 minutes) with an overview of the proposed Project and the preferred route.

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 Substation and Line Project Facts

Route length:Approximately 2.3 miles
Location:Greenwich, Connecticut
Line voltage:Two 115,000-volt (115-kV)
transmission lines
Substation:One new transmission-level
Siting review
The Connecticut Siting Council
Estimated timetable:
  • Municipal Consultation Filing (MCF) – February 6, 2015
  • Public Open House – March 3, 2015
  • Connecticut Siting Council (CSC) application filing – Second
    Quarter 2015
  • CSC Review – begins Second Quarter 2015
  • CSC Decision – Second Quarter 2016
  • If approved, submit Development & Management Plan to CSC
    for approval – Third Quarter 2016
  • Start of construction (pending all necessary approvals) –
    August 2016
  • Estimated in-service date – December 2017

Municipal Consultation Filing 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 phase is the first step in 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.

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.

The filing consists of one volume, with Sections A - K. Some sections are quite large and may take a considerable amount of time to download, depending on the size of the modem being used.

Table of Contents


A. Purpose of the Filing

B. Project Contacts

C. Description of Filing Contents

D. Project Need

E. Description of the Project

F. Existing Environmental Conditions

Existing Environmental Conditions (contd.)

Existing Environmental Conditions (contd.)

G. Environmental Effects and Mitigation

H. Underground Transmission System Design

I. Construction Procedures and Methods

J. Electric and Magnetic Fields

K. Project Schedule and Costs

General Glossary of Terms

Appendix A: Greenwich Substation Site Plan Drawings

Appendix B: Cos Cob Substation Site Plan Drawings

Appendix C: Preferred Route Segments

Map E-6A

Map E-6B

Map E-6C

Map E-6D

Map E-6E

Map E-6F

Map E-6G

Map E-6H

Map E-6I

Appendix D: Heritage Consultants, LLC – Preliminary Archeological Assessment of the Project Region

Appendix E: CT Dept. of Energy and Environmental Protection Letter

Appendix F: CT Siting Council EMF Best Management Practices

Open Houses

During the Municipal Consultation Filing period, an open house was held in Greenwich to give residents an opportunity to learn more about this Project, ask questions and provide comments on the proposed Project with subject matter experts from Eversource.

The open house was held on Tuesday, March 3, 2015, 6 - 8 p.m., at the Greenwich Town Hall, Town Hall Meeting Room, 101 Field Point Road, Greenwich, Connecticut 06830.

Contact Information

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

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