ISO New England — Market Overview

ISO New England's operating fleet is overwhelmingly renewable-driven, with solar energy comprising the vast majority of plants and capacity, and Massachusetts and Maine leading in regional contributions.

Dominant Solar Presence with Minimal Conventional Generation

• The ISO New England operating fleet is heavily dominated by solar, accounting for 969 plants and 4.8 GW of capacity.

• Battery storage represents a significant, though smaller, portion with 37 plants totaling 192 MW.

• Conventional generation is minimal, with Oil & Petroleum comprising only 4 plants (626 MW) and Natural Gas limited to 2 plants (15 MW).

State Contributions and Largest Plants

• Massachusetts leads in plant count with 564 facilities contributing 2.4 GW of capacity to the ISO New England fleet.

• Maine follows with 160 plants and 1.4 GW, while Connecticut has 100 plants totaling 816 MW.

• The largest single plant is Stony Brook (MA) at 541.5 MW, followed by Freedom Pine Solar (ME) at 250 MW and Broadleaf Solar (CT) at 200 MW.

The ISO New England region demonstrates robust development activity, particularly in offshore wind, yet faces increasing regulatory and environmental scrutiny, especially concerning new hydroelectric and battery storage projects.

Development Activity and Regulatory Scrutiny

• A total of 1,054 news articles were identified, indicating a high level of activity within the ISO New England region.

• Development-related news accounted for 248 articles, highlighting ongoing project initiatives.

• Regulatory news comprised 250 articles, suggesting significant policy and oversight engagement.

• The Revolution Wind offshore project is notably over 95% complete, signaling a major construction milestone set for August 2026.

Emerging Permitting and Environmental Challenges

• Recent signals indicate increasing scrutiny in project permitting, with public hearings requested for the Warrensburg Hydroelectric Project and the Mill Pond Hydroelectric Project in August 2026.

• A town demand for corrective action at a battery storage facility due to a noise complaint in August 2026 points to localized environmental and community concerns.

• Multiple notices regarding water quality certification applications for hydro projects, such as Oswego Hydro Partners, LP and Lyonsdale Associates, LLC, demonstrate continued environmental review processes.

Interconnection Queue Activity in ISO New England

• ISO New England currently reports no active projects in its interconnection queue, indicating a significant lack of future generation development visible through this pathway.

• This absence contrasts sharply with many other ISOs that typically have thousands of megawatts of proposed capacity awaiting interconnection.

Implications for Future Fleet Transformation

• Given the zero queue pipeline, there is no visible future growth or transformation of the generation fleet through new large-scale interconnections.

• The current fleet comprises 1,012 plants with 5.6 GW of capacity, and the absence of a queue suggests that any future capacity additions would likely stem from smaller, distributed generation not subject to the ISO queue process, or from projects in earlier development stages not yet filed for interconnection.

The complete absence of projects in ISO New England's interconnection queue signals a unique development landscape, suggesting that any significant future capacity additions or technological shifts are not currently materializing through traditional large-scale project development and interconnection processes. This could imply a focus on grid modernization, demand-side management, or smaller, often behind-the-meter resources that do not enter the ISO queue.