What DASI Changed
ISO New England introduced DASI for the March 1, 2025 operating day. The design retired the seasonal Forward Reserve Market and added day-ahead ancillary services and constraints so the day-ahead plan can cover both forecast load and contingency reserves.
- Flexible response services: DASI includes products analogous to 10-minute spinning, 10-minute non-spinning, and 30-minute operating reserves.
- Energy imbalance reserve: The market added a product intended to bridge the gap between cleared day-ahead supply and forecast demand.
- Co-optimization: Resources submit energy and ancillary-service offers into the day-ahead process, so cost outcomes depend on offers, constraints, reserve requirements, and system conditions.
What the Official Record Does Not Prove
The prior version of this page stated that DASI was driving retail bills higher across New England and projected a 15–30% commercial-buyer impact. Those claims were too broad and have been removed. Wholesale settlement costs can flow through to customers, but the timing and amount depend on the account and rate structure.
- Fixed-price supply: A supplier may have priced ancillary-service exposure into the contract rather than passing through a new line item.
- Pass-through contracts: Regulatory-change, market-rule, reconciliation, or ancillary-service clauses can change the allocation, but the contract language controls.
- Utility default service: Procurement timing and approved tariff design affect when wholesale costs enter rates.
- Local delivery charges: DASI is a wholesale-market mechanism; it should not be presented as a direct forecast for distribution, transmission, or all-in delivered rates.
Post-Implementation Changes Buyers Should Track
ISO-NE’s project page, updated July 2, records active post-implementation work. The non-performance factor used in reserve calculations decreased from 120% to 115% for the May 1, 2026 operating day. ISO-NE also lists a future strike-price adjustment and a lower forecast energy requirement with an implementation date still to be announced.
These changes are evidence that the market design is being tuned. They are not a promise of a particular retail-rate reduction. The current DASI complaint and reform path are owned by the $921 million DASI complaint analysis, which separates complaint figures from final FERC outcomes.
Commercial Buyer Checklist
- Map contract treatment: Identify whether energy, capacity, ancillary services, and regulatory changes are fixed, passed through, or reconciled.
- Normalize comparisons: Compare supplier offers and utility default service using the same inclusions, time period, load shape, and delivery-charge assumptions.
- Watch the rule path: Track ISO-NE implementation notices and FERC action before budgeting an assumed DASI reform benefit.
- Evaluate flexible load separately: Demand response may be useful, but program eligibility, dispatch rules, telemetry, and revenue require program-specific verification.
Source trail: ISO New England DASI project overview and ISO-NE April 2026 Participants Committee materials, reviewed July 11, 2026.