ISO New England projected approximately $421 million in power transmission reliability investments across the region through 2028, according to its latest Regional System Plan Project List, released in March 2025.
The quarterly update showed steady progress on system upgrades critical to ensuring a reliable and efficient electric grid. While no new projects were added in the latest update, five existing projects were placed into service in recent months. There are currently 18 active projects underway—six are under construction, and 12 are in the planning phase. No projects are currently classified as “proposed.”
Massachusetts and Maine lead the activity with nine and six active projects, respectively. Connecticut, Rhode Island, and New Hampshire each have one ongoing project, while Vermont currently has none.
Since 2002, ISO New England’s transmission planning efforts have supported over $13 billion in infrastructure investment, resulting in 879 completed project components. These upgrades are primarily aimed at maintaining system reliability but have also helped reduce congestion on the transmission system and paved the way for cleaner, more cost-effective energy.
Planning for a Reliable and Clean Energy Future
The Regional System Plan Project List is published three times a year and provides a snapshot of the projects needed to meet federally mandated reliability standards and support the region’s evolving energy landscape. As part of its planning process, ISO New England continually reassesses project timelines and scopes to reflect changing system conditions—such as shifts in demand, generator retirements, or the addition of new energy resources.
The planning process is collaborative and transparent, anchored by input from the ISO’s Planning Advisory Committee. The committee includes stakeholders ranging from transmission and generation owners to state agencies and community groups. The next meeting is scheduled for April 29 at 9 a.m. and will be held via Webex.
Evolving Energy Trends May Influence Future Projects
Regional energy trends, including strong commitments to energy efficiency and the rise of distributed energy resources like solar, continue to influence transmission needs. In some cases, these trends may allow for the deferral of planned transmission projects or eliminate the need for new infrastructure altogether.
Similarly, market-based alternatives—such as demand response programs or the addition of new generating resources—may help alleviate pressure on the grid and reduce the scope or urgency of traditional transmission upgrades.
