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Seacoast Reliability Project

The N.H. Seacoast Region is a leader in economic growth in the state, so there is a continued need to maintain reliable electric service.

The Independent System Operator of New England (ISO-New England) has determined that the Seacoast area needs additional transmission capacity to support the reliable delivery of electric power to meet the region's current and future demand.

To meet this need, we have proposed, and ISO-New England has approved, a new 115-kilovolt (kV) transmission line that will extend approximately 13 miles between two existing substations in Madbury and Portsmouth, N.H., along with associated substation upgrades. This is known as the Seacoast Reliability Project.

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The project will help improve the transmission system in the Seacoast area so that our customers will have reliable electric power to meet their current and growing energy needs. It will also ensure that the area's electric grid conforms to national and regional reliability standards. See the one-page Seacoast Reliability Project information sheet for more details.


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Estimated Timetable (subject to change):

  • Application filing with the New Hampshire Site Evaluation Committee (SEC): April 12, 2016
  • Open Houses & SEC Public Information Sessions: July 2016
  • SEC Bus Tour of Project Route: August 31, 2016
  • SEC/Agency Joint Public Hearings: August 31 & September 1, 2016
  • Application Amendment Filing with SEC: March 29, 2017
  • SEC Proceedings: Third/Fourth Quarter 2018
  • SEC Decision Anticipated: First Quarter 2019
  • Start of Construction (pending SEC approval): First Quarter 2019
  • 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 N.H. 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.

Based on a recommendation by the N.H. Department of Environmental Services, the N.H. Site Evaluation Committee required Eversource to conduct a detailed review comparing the feasibility of the proposed “jet plow” burial method to that of “Horizontal Directional Drilling” (HDD), which would place the Seacoast Reliability Project power cable deep beneath the bay by means of a significant drilling operation. Eversource filed its report with the SEC on July 1, 2018.

Community Engagement

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.

Two public hearings (hosted by the SEC) were held on August 31, 2016, in Rockingham County and on September 1, 2016, in Strafford County.

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

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. 

Contact Information

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