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Greenwich Substation and Line Project

Eversource is constructing two, new, underground transmission lines; modifying the Cos Cob Substation to accommodate the new lines; and removing the warehouse for construction of the new Greenwich Substation.  

PROJECT DESIGN

As part of always working to serve you better, Eversource is constructing two, 115-kilovolt (kV) transmission lines and building 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 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 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

Next Steps (estimated timetable, subject to change):

  • Estimated project completion: 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 Decision 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. The CSC issued its Decision 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. The CSC issued its Decision on June 21, 2018.

On October 3, 2018, Eversource submitted the Greenwich 115-kV Underground Transmission Lines D&M Plan to the CSC. The CSC issued its Decision on the D&M Plan for the underground transmission lines 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. The CSC issued its Decision on the D&M Plan for the Greenwich Substation on March 29, 2019, including the following seven appendices:

On May 3, 2019, Eversource submitted the Indian Harbor Crossing D&M Plan for the 115-kV Double-Circuit Underground Transmission Lines to the CSC. The CSC issued its Decision on May 24, 2019, including the following seven appendices:

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.

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

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. Eversource representatives will occasionally go door-to-door to communicate with neighbors about the nearby construction project. They may leave an informational doorhanger at a home or business or knock on the door to provide an update on project work.

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.

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.

Construction of the new 115-kV underground transmission line began the week of April 1, 2019. We anticipate that it will be complete in 2020.

Week of September 15, 2019:  

Day Work:

  • Excavation work will continue at Cos Cob Station and the NRG facility on Sound Shore Drive near Cos Cob Park.
  • Continuous 24-hour work has been approved for the Sound Shore Drive crossing beginning at 7 a.m. on Thursday, September 12, through 6 p.m. on Monday, September 16. Based on our progress, an extension may be obtained for next week. Sound Shore Drive will be closed between Sachem Road and the Cos Cob train station parking lot to all through-traffic during this time. Access to Cos Cob Park, train station, office buildings, and condos will be maintained from Strickland Road as shown in TMP Detour Plan 1A. Access will be allowed to local truck deliveries, emergency vehicles, residents and employees within the work zone. When approaching the work area, please inform the police officer of your destination.
  • Splice vault installation will occur in the grassy shoulder of Sound Shore Drive near I-95, Exit 4. This work will take place between 7 a.m. and 6 p.m. Monday through Friday and between 9 a.m. and 5 p.m. on Saturdays. A single lane closure with alternating traffic will occur on Sound Shore Drive between 9 a.m. and 3 p.m. Monday to Friday, and 9 a.m. and 5 p.m. on Saturdays. 
  • The crossing underneath I-95 will begin this week. This activity will take place in the grassy medians between the I-95 Exit 4 ramps. For more information on the crossing method, please refer to the Development & Management Plan. This work will take place between 7 a.m. and 6 p.m. Monday through Friday and between 9 a.m. and 5 p.m. on Saturdays. Additionally, the rock and soil material removed from beneath I-95 will be hauled to an offsite disposal facility at night using a single lane closure on I-95 at Exit 4 between the hours of 10 p.m. to 5 a.m. Sunday to Thursday. This hauling work must occur at night due to traffic restrictions.
  • Excavation work will continue in the Davis Avenue traffic island near the Indian Harbor crossing and Home Place. This work will take place between 9 a.m. and 3 p.m. Monday to Friday, and 9 a.m. and 5 p.m. on Saturdays with a single lane closure and alternating traffic.

Night Work:

  • Excavation work will continue on Indian Field Road between Cobb Island Drive and Bruce Park Drive. This work will take place at night, Sunday through Thursday, from 8 p.m. to 5 a.m. Traffic will be detoured as shown in Traffic Detour Plan 4.
  • Excavation work will continue on Museum Drive. This work will be done at night, Sunday through Thursday, from 8 p.m. to 5 a.m. There will be a single lane closure with alternating traffic.
  • In support of the crossing underneath I-95, the rock and soil material removed from beneath I-95 will be hauled to an offsite disposal facility at night using a single lane closure on I-95 at Exit 4 between the hours of 10 p.m. to 5 a.m. Sunday to Thursday. This hauling work must occur at night due to traffic restrictions.
  • Continuous 24-hour work has been approved for the Sound Shore Drive crossing beginning at 7 a.m. on Thursday, September 12, through 6 p.m. on Monday, September 16. Based on our progress, an extension may be obtained for next week. Sound Shore Drive will be closed between Sachem Road and the Cos Cob train station parking lot to all through-traffic during this time. Access to Cos Cob Park, the train station, office buildings, and condos will be maintained from Strickland Road as shown in TMP Detour Plan 1A. Access will be allowed to local truck deliveries, emergency vehicles, residents and employees within the work zone. When approaching the work area, please inform the police officer of your destination.

Last year, we began the removal of the existing warehouse building at 290 Railroad Avenue. We have completed the building demolition, and site preparation for construction of the new Greenwich Substation started in August 2019. Foundation installation is currently in progress. The substation will be surrounded by a 15-ft. brick façade wall and landscaping. 

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.
 
Information About Rock-Blasting Activities

Blasting activities began on Wednesday, August 28, 2019, and were completed on Friday, September 13, 2019. No blasting occurred outside the property lines of 290 Railroad Avenue. Compared to using mechanical rock-removal equipment, such as construction-grade jackhammers, blasting is a safe, fast and efficient way to remove rock. Because there is a solid layer of rock on the Greenwich substation property, construction includes rock removal by mechanical means and controlled blasting. The Blasting Plan was developed in coordination with the town of Greenwich and approved by the Connecticut Siting Council (CSC). 

Eversource’s Project Partners for Blasting Activities

McPhee Electric, an Eversource contractor that has been working on the Greenwich Substation and Line Project, employed Blastech, Inc., a licensed blasting company with experience working in Greenwich, to perform the blasting activities at the site. Blastech has retained DRS Seismic Consultants, LLC to conduct vibration monitoring and property surveys during the blasting work. 

We anticipate that construction of the new substation will be complete in 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 ProjectInfo@eversource.com or call 800-793-2202.