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Seacoast Reliability Project

To help ensure that the New Hampshire Seacoast Region can continue to grow and thrive, Eversource has completed construction of the Seacoast Reliability Project, a new transmission line connecting two existing substations.

The project includes a new 115-kilovolt (kV) transmission line extending approximately 13 miles between substations in Madbury and Portsmouth, N.H., along with associated substation upgrades. 


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The project was placed into service on May 29, 2020. The new transmission line 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.

Eversource invested more than $123 million in this New Hampshire project designed to bolster the regional infrastructure. While the project is resulting in direct benefits for New Hampshire communities, residents and businesses ― including the enhanced system reliability for customers, creation of local jobs, and property tax payments in host communities ― the cost of the project will be paid by all electric customers in New England.

See the one-page Seacoast Reliability Project information sheet for more details. 

New Hampshire Site Evaluation Committee

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 review process, as defined by the New Hampshire state statutes. On December 10, 2018, the SEC voted unanimously to approve the construction of the project. On January 31, 2019, the SEC issued its written order, reaffirming its oral approval. The committee’s approval followed a series of public information sessions and public hearings in Concord and in the communities that host the new 115-kV transmission line.

Click here for Post-Certificate Filings for the project, including reports for and from the Department of Environmental Services (NHDES).

Next Steps (estimated timetable, subject to change): 

Environmental surveys: Weekly into 2021 until adequate vegetation cover

Cable House (Little Bay Shore in Durham) relocation and restoration: August - December 2020

Landscape Mitigation and Right of Way Restoration are complete

Project Outreach

We are committed to being a good neighbor and keeping you informed about our work. Similar to the siting and construction phases of the project, we will continue working directly with the community to provide information about the restoration and any remaining close-out work activities and to quickly answer any questions or concerns. Some of the ways that we communicate with residents, businesses and others in the community include:

Project Information Letters: Letters mailed to property owners along the right of way (power line corridor), sharing project milestone information.

Public Open Houses: Information sessions, which were held prior to the start of construction.

Field Outreach Representatives: Eversource representatives are on-site prior to, and during, work. They communicate with local residents and businesses in-person about the project and respond to any questions or concerns.

The safety of our employees, our customers and the public is our top priority during the ongoing coronavirus public health crisis. Our commitment to safety, first and always, is continuous.

Eversource is committed to delivering safe, reliable service to our customers. This commitment has taken on even more importance during these unsettled times. We continue to call on our employees and contractors to perform essential work in the field that maintains and improves the reliability of our networks and serves customers' best interests while also adapting our work practices to incorporate social distancing, proper protective equipment, heightened hygiene, and other best practices to protect their, and the public's, health and avoid the spread of coronavirus.

In addition to relying on alternate communications channels to keep customers safe and informed (letters, emails and phone calls), we will resume our use of door hangers as a part of our outreach efforts. Eversource Field Outreach representatives will leave these notifications that include information on our work in rights-of-way and who to contact with any questions - without knocking on doors. Eversource representatives will continue to abide by all COVID-19 safety guidelines, which include wearing personal protective equipment, following social distancing, enhanced sanitizing requirements and other federal and state health and safety guidelines.

Project Webpage: Route maps, project schedules, regulatory filings, regular project updates and contact information.

Municipal Meetings: Project update meetings with city and town officials held regularly throughout various phases of the project.

Contact Us

For any questions or concerns about the Seacoast Reliability Project, please call us at 888-926-5334, email us at, or discuss directly with the Eversource Field Outreach Representative. We will make every effort to promptly respond to your questions or address your concerns.

In the unlikely event that we are unable to address your concerns to your satisfaction, a process has been developed by the New Hampshire Counsel for the Public and Eversource to provide more help with resolving issues. That process can be found here (see pages 212-218).