ISO-NE: ISO New England
ISO New England operates the electric grid across six New England states, managing a region historically dependent on natural gas while transitioning toward offshore wind and clean energy. The grid serves approximately 14 million people with unique winter reliability challenges.
Source: ISO-NE
Last updated: December 22, 2024
Coverage Area
ISO-NE serves Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. The region has limited indigenous fuel resources and relies heavily on imported natural gas, which creates both price volatility and winter reliability concerns when gas supplies tighten.
Natural Gas Dependence & Winter Challenges
New England's heavy reliance on natural gas—over 50% of generation—creates unique challenges during cold winters when gas is also needed for heating. Pipeline constraints can limit gas availability for power plants, driving electricity prices to extreme levels during cold snaps and raising reliability concerns.
ISO-NE has implemented various programs to address winter reliability, including pay-for-performance capacity market rules and inventoried energy programs that compensate resources for maintaining fuel supplies.
Offshore Wind Transformation
New England states have collectively contracted for over 10 GW of offshore wind, representing a fundamental transformation of the regional generation mix. Massachusetts, Rhode Island, and Connecticut have all signed contracts for major projects in federal lease areas south of Martha's Vineyard and in the Gulf of Maine.
However, the offshore wind industry has faced challenges including cost increases, supply chain constraints, and project delays. Several contracts have been renegotiated or cancelled, though states remain committed to their offshore wind goals.
State Policy Coordination
All six New England states have clean energy mandates, though they vary in ambition and approach. Coordinating procurement and transmission planning across multiple states with different policies is an ongoing challenge, though regional transmission planning processes are improving coordination.
State Guides in ISO-NE
State guides for Massachusetts, Connecticut, and Maine coming soon.
Frequently Asked Questions
Why does New England have winter reliability concerns?
Heavy dependence on natural gas combined with pipeline constraints means gas supplies can tighten during cold weather when heating demand is high, potentially limiting fuel availability for power plants.
How will offshore wind change the New England grid?
Offshore wind will provide significant clean generation during winter months when solar is less productive, helping address both clean energy goals and winter reliability. Projects will require major transmission upgrades and interconnection infrastructure.
What is the Forward Capacity Market?
ISO-NE's Forward Capacity Market procures capacity commitments three years in advance to ensure adequate resources during peak demand. The market has been reformed multiple times to address changing resource mix and reliability needs.