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Seacoast Reliability Project 

With electric demand in portions of the New Hampshire Seacoast Region growing at twice the rate of the rest of the state, additional transmission capacity is needed to support the reliable delivery of electric power to the region.

To address this concern, Eversource has proposed the Seacoast Reliability Project. The project includes substation upgrades and a new 115-kilovolt (kV) transmission line connecting two existing substations in Madbury and Portsmouth. The proposed line will pass through Madbury, Durham, Newington and Portsmouth, New Hampshire. 

At Eversource, we're always working to serve you better. This 13-mile project will improve the transmission system in the New Hampshire Seacoast area so customers will have reliable electric power to meet their growing energy needs, in keeping with national and regional reliability standards.

For an overview of the project, please see the project's information sheet.Map of the Seacoast Reliability Project.

 * Click to Enlarge

Project Facts:

  • Route Length: Approximately 13 miles
  • Towns: Madbury, Durham, Newington, and Portsmouth, New Hampshire
  • Line Voltage: 115,000 volt (115-kV) overhead, underground and submarine transmission lines
  • Siting Review By: New Hampshire Site Evaluation Committee (SEC)

Estimated Timetable (subject to change):

  • Application filing with SEC: April 12, 2016
  • Open Houses & SEC Public Information Sessions: July 2016
  • SEC Bus Tour Site Inspection: August 31, 2016
  • SEC/Agency Joint Public Hearings: August 31 & September 1, 2016
  • Application Amendment Filing with SEC: March 29, 2017
  • SEC Proceedings:Second/Third Quarter 2018
  • SEC Decision Anticipated: Third/Fourth Quarter 2018
  • Start of Construction (pending SEC approval): Third/Fourth Quarter 2018
  • Projected In-Service Date: Fourth Quarter 2019


For an electric transmission line project, such as the Seacoast Reliability Project, the New Hampshire Site Evaluation Committee (SEC) Application Filing is part of the siting regulatory view process, as defined by the New Hampshire state statutes.


On April 12, 2016, Eversource applied to the SEC for a Certificate of Site and Facility (Application) for the construction of the Seacoast Reliability Project.

Following this Application, discussions with the communities continued, and Eversource obtained the necessary land rights to accommodate requests including underground design changes in Newington, and modifications to the overhead design in several locations based on input received from town officials, the NH Department of Transportation, and property owners along the corridor. These changes are reflected in an amendment to the SRP application submitted to the SEC on March 29, 2017.

Open Houses & Public Information Session

Involving the public and municipal leaders is an important part of the project’s planning process.  

Two pre-application Open Houses and Public Information Sessions were held in April 2015 in both Rockingham and Strafford counties. Eversource also held two more post-application Open Houses and SEC Public Information Sessions in both counties in July 2016.

These gatherings gave the public an opportunity to learn more about this project and to ask questions. Residents also learned more about additional opportunities to participate in the SEC’s evaluation of the project.

Public Hearings & Bus Tour

The SEC also hosted two public hearings to give the public further opportunity to ask questions and provide comments on the project.

The public hearings were held on August 31, 2016, in Rockingham County and on September 1, 2016, in Strafford County.

Additionally, Eversource hosted a bus tour site inspection for the SEC and other interested parties on August 31, 2016, to review the project route. 

Contact Information

For more information about the Seacoast Reliability Project, please send an email to or call 888-926-5334.