Frequently Asked Questions

National Grid and Eversource, long-standing and committed community partners, are teaming up to deliver a set of critical reliability projects in the Greater Boston and southern New Hampshire area. Our Solution comprises various projects, each with individual merit, which together address the reliability problems identified by ISO-NE (see below), improve the region’s power system, and meet the customer demand for power for years to come. The Solution combines our decades of experience and commitment to customers, offering the most cost-effective and readily implementable projects to benefit residents and businesses in Massachusetts and New Hampshire. The notable projects are:

Merrimack Valley Reliability Project – new overhead 345-kilovolt (kV) line in existing transmission rights-of-way in the towns of Tewksbury, Andover, and Dracut, MA, and Pelham, Hudson, Windham, and Londonderry, NH.

Woburn to Wakefield Line – new 345-kV underground cable in the towns of Woburn, Winchester, Stoneham, and Wakefield, MA.

Mystic to Woburn Line – new 115-kV underground cable in the towns of Woburn, Winchester, Medford, Somerville, Boston (Charlestown), and Everett, MA.

Created in 1997 and regulated by the Federal Energy Regulatory Commission, ISO New England (ISO-NE) is the area’s independent power system operator. ISO-NE oversees the bulk electric power system, including power plants and the transmission system throughout New England, and helps set the prices, terms, and conditions of our region’s energy supply.

ISO-NE has three essential roles: 1) coordinating and directing the flow of electricity over the region’s transmission system, 2) designing and overseeing the wholesale market for electricity, and 3) planning for the region’s energy future. The third role is especially relevant for the Greater Boston and New Hampshire Solution; in this case, ISO-NE has conducted assessments and identified specific reliability issues in New Hampshire and Greater Boston area that must be addressed promptly.

National Grid and Eversource, the region’s experienced and long-standing utilities, have taken great care to assemble a Solution that meets the region’s immediate and future electric power needs, while balancing consumer cost with community and environmental impact. The various projects within the Solution are designed to be the least-impactful, most cost-effective method to bring the greatest benefits to consumers. This is why ISO-NE selected the projects within the Greater Boston and New Hampshire Solution as the “preferred” solution.

There are multiple tangible benefits from our proposed Solution:

  • Provides the most cost-effective solution to meet customer needs
  • Improves power system reliability and quality
  • Delivers substantially greater levels of power import capacity, which will enable access to lower-cost and cleaner power sources for consumers
  • Offers flexible design and technology
  • Contains costs and minimizes environmental impact by working in existing rights-of-way and within existing roadways.
  • Boosts the regional economy with local jobs and increased local property tax revenue in Massachusetts and New Hampshire.
  • Supports the region’s economic health and demand for electricity for many years to come

According to Eversource and National Grid’s cost estimates, and verified in an independent study managed by ISO-NE, in February 2015, the Greater Boston and New Hampshire Solution capital costs were about $520 million. An additional $220 million of “common projects” would also be completed at the same time. At that time, the Greater Boston and New Hampshire Solution was more than $250 million lower in cost than the alternative.

As we continue to refine our project engineering and gather additional information on materials and other resources, we have identified some individual project cost estimate fluctuations – both up and down – but the aggregate cost remains $250+M less than the alternative.

As determined by ISO-NE, all New England energy customers pay for regionally beneficial transmission projects such as these.

National Grid and Eversource have begun petitioning the Massachusetts Department of Public Utilities and the New Hampshire Site Evaluation Committee for project implementation approvals. Please note the siting processes vary in Massachusetts and New Hampshire. During this time, National Grid and Eversource will engage in direct and regular communication with stakeholders in each community that the projects touch Visit the Siting Process section for more details.

All of the projects require various local, state, and/or federal approvals; fortunately, National Grid and Eversource have decades of experience in siting, building and maintaining transmission projects in New England. The siting and permitting window for the projects is expected to be around 12 to 24 months, with some put in service in 2017, others by the end of 2018, some by late-2020.

National Grid and Eversource have taken great care to identify environmental resources such as soils, water resources, wetlands, water quality, vegetation, wildlife, and threatened or endangered species. During the planning, permitting, and construction stages of the project, our team will work with local, state, and federal agencies to establish work methods that minimize or eliminate the impact to these resources. As always, we will conduct all construction in an environmentally acceptable manner that will meet all of our regulators’ expectations and avoid long-term adverse impacts.

The transmission lines in our Solution are an efficient and effective way to transmit energy over great distances. For instance, the overhead 345-kV lines proposed in the Merrimack Valley Reliability Project and the underground Woburn to Wakefield line are typically capable of carrying enough electricity during peak times to power 400,000 homes.

Yes; however, no viable non-transmission alternative, alone or in combination, has come forward to address the reliability need.

Please call our toll-free hotline at 844-646-8427 or email us at The website,, will also be updated regularly throughout the siting and construction phases.