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Greenwich Substation and Line Project

Eversource is modifying the Cos Cob Substation to accommodate the new transmission lines. We expect to start construction of the new underground lines and the new Greenwich Substation in early 2019.  

PROJECT DESIGN

As part of always working to serve you better, Eversource is preparing to construct two, new 115-kilovolt (kV) transmission lines and build a new substation to improve reliability in Greenwich, Connecticut.

The new lines will 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 new lines will run underground, primarily under town streets, including those in Bruce Park.

The project also includes modifications at 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 approval 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

Next Steps (estimated timetable, subject to change):

  • Start of construction for the new underground transmission lines: March 2019
  • Start of construction on remaining project sections: Mid-2019
  • Estimated project completion: Early 2020

DEVELOPMENT & MANAGEMENT PLANS

Following receipt of the CSC’s application approval, Eversource is required to submit construction plans, called Development & Management Plans (D&M Plans), to the CSC for its approval before construction can begin. These plans include, but are not limited to, further design detail, final site plan, construction sequencing, traffic management plans, work hours and laydown/staging areas. There are multiple D&M Plans for this project.

On February 20, 2018, Eversource submitted the Cos Cob Substation D&M Plan to the CSC. It was approved by the CSC on April 12, 2018.

On May 18, 2018, Eversource submitted the Greenwich Substation Warehouse Building Demolition and Pre-Construction Site Preparation D&M Plan to the CSC. It was approved by the CSC on June 21, 2018.

On October 3, 2018, Eversource submitted the Greenwich 115-kV Underground Transmission Lines D&M Plan to the CSC. The D&M Plan for the underground transmission lines was approved by the CSC on January 17, 2019, including the following eight appendices: 

On February 4, 2019, Eversource submitted the Greenwich Substation Construction D&M Plan to the CSC, including the following seven appendices:

Eversource intends to submit the remaining D&M Plan for the crossing of Indian Harbor to the CSC in the coming months. It will be posted here when available.

CONSTRUCTION UPDATES

First, please know that Eversource takes every safety precaution while working in local communities, and that all people working on the construction project carry identification.

Eversource is committed to updating neighbors, businesses and the community about project activities, especially during construction. Public outreach and coordination with the Town of Greenwich is ongoing throughout the project.

Please note that the project work will not interrupt electric service to homes or businesses.

Construction will take place in phases. Work may occur in several locations along the project route at the same time, and work hours will be location-specific. Please refer to the Traffic Management Plan (TMP) for detailed information on work hours.

The sections below feature construction updates for both substations and the new underground transmission line. As construction progresses, this section will be updated with information for each street affected by construction of the underground lines. Please keep in mind that the construction schedule is approximate and may change. Due to weather or other circumstances, from time to time the crews may need to work longer hours or work on a Sunday.

Cos Cob Substation

Modifications to the Cos Cob Substation began in May 2018 and will continue throughout 2019.

Work activities within the existing substation property include vegetation removal; grading, digging and trenching; installation of new equipment and retaining walls; and then restoration of areas disturbed by the work.

Work hours will typically be 7 a.m. to 6 p.m., Monday through Friday, and 9 a.m. to 5 p.m. on Saturdays.

Underground Transmission Line Construction

Preliminary survey work will begin in town streets in February 2019. Work hours will be location-specific and in accordance with the Traffic Management Plan.

Construction of the new 115-kV underground transmission line will begin in late February 2019 and is anticipated to be complete in early 2020.

Greenwich Substation

Preparation for the removal of the existing warehouse and pre-construction site preparation for the substation began in September 2018, and will continue through early 2019.

Preparation includes the installation of a temporary security fence, removal of the building and related materials, vegetation removal, and grading of the site.

Work hours will typically be 7 a.m. to 6 p.m., Monday through Friday, and 9 a.m. to 5 p.m. on Saturdays.

Construction of the new Greenwich Substation will begin following the CSC's approval of the D&M Plan, and is anticipated to be complete in early 2020.

TRAFFIC MANAGEMENT PLAN

Working in consultation with town and state officials, including the Connecticut Department of Transportation, Eversource has developed a Traffic Management Plan (TMP) for construction of the Greenwich Substation and Line Project.

The TMP includes hours of construction, area-specific traffic controls and detour plans for each segment of the underground line route.

Some of the files below are large in size and might take some time to load or download. Please note, detour plans are subject to change and may be updated.

COMMUNITY OUTREACH

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.

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

CONTACT INFORMATION

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