ISO-NE Capacity Market Overhaul: Prompt Auctions Replace 3-Year Forward Model

Why ISO-NE Is Abandoning the Forward Model

For over a decade, ISO-NE has procured capacity three years in advance. This forward model was designed to give generators a long enough runway to build new plants. But the accelerating pace of change—rapid renewable buildouts, offshore wind delays (Revolution Wind's stop-work order is a prime example), and volatile winter fuel markets—has made 3-year forecasts unreliable.

The new prompt auction framework shortens the commitment window dramatically. Instead of locking in capacity three years out, the system will procure resources closer to the delivery period, using seasonal (summer/winter) commitment windows. This gives the market more accurate demand signals and reduces the risk of paying for resources that never materialize.

What Changes for Commercial Buyers

For commercial and industrial electricity consumers across the six New England states, this reform carries direct procurement implications:

• Shorter price visibility: Capacity costs, currently locked 3 years ahead, will become more dynamic. Budget cycles must adapt to shorter forward curves.
• Seasonal pricing: Winter capacity will likely clear at a premium to summer, reflecting New England's persistent natural gas constraint. The January 2026 cold snap—which triggered a DOE emergency order and forced oil-fired generation online—underscored this asymmetry.
• Resource accreditation changes: Phase 2 of the reform (filing expected late 2026) will overhaul how generators prove their availability. Intermittent resources (wind, solar) will face tighter performance standards.