ISO-NE

Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, United States.

Wholesale design: nodal energy and ancillary-services markets with a Forward Capacity Market transitioning toward a prompt seasonal design.

Operator
ISO New England
Nominal frequency
60 Hz
Where energy trades

Where does energy trade in ISO-NE?

Energy in ISO-NE trades in 2 layers: Day-Ahead Energy and Ancillary Services Market and Real-Time Energy and Reserve Market. Participation in Real-Time Energy and Reserve Market is mandatory. Scheduling and settlement, where the cited sources give them, are in the table below.

Layer Scheduling Settlement
Day-Ahead Energy and Ancillary Services Market hourly day-ahead locational marginal pricing and day-ahead ancillary-service clearing prices
Real-Time Energy and Reserve Market (mandatory) five-minute real-time dispatch and pricing real-time locational marginal pricing and reserve clearing prices
What a battery can sell

What ancillary services can a battery sell in ISO-NE?

ISO-NE has 7 ancillary-service products, across 5 families — regulation, contingency reserve, replacement reserve, reactive power & voltage and other services: Blackstart Service, Energy Imbalance Reserve, Regulation Service, Ten-Minute Non-Spinning Reserve, Thirty-Minute Operating Reserve, Ten-Minute Spinning Reserve, Voltage Support Service. Response timing, direction and eligibility for each are in the table below; a product's full record lists the official sources behind it.

Every value below comes from the official sources listed in that product's full record. Most products cite more than one, and the published sources do not say which of them states each individual value, so the binding is to the product's record rather than to a single document. A missing line means the source does not state that value — never that the value is zero.

Scroll the table sideways for the rest of the columns →

7 ancillary-service products in ISO-NE, grouped into 5 families. Each row runs left to right through one product's life: how it activates, how quickly it has to respond, how long it has to keep delivering, and how it is bought.
Service How it activates Response Sustained delivery Procurement
Regulation
Regulation Service Regulation Response type pre-contingency continuous Trigger continuous movement within each resource's assigned regulation range Dispatched by automatic generation control signal sent every four seconds No deadline established Four seconds is the control-signal interval, not a universal full-response requirement. Through real-time Pricing design regulation capacity and service/performance compensation under Market Rule 1
Full record for Regulation Service — document bound, page for these figures not recorded
What it is for

Correct area-control error and maintain interconnection frequency through automatic resource movement.

What the source does not state

It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Contingency reserve
Energy Imbalance Reserve EIR Response type pre-contingency flexibility Trigger forecast real-time energy requirement above the day-ahead cleared energy position Dispatched by day-ahead co-optimization positions eligible resources; any later energy deployment occurs through real-time dispatch Through day-ahead Pricing design day-ahead EIR clearing price with settlement interactions defined in Market Rule 1
Full record for Energy Imbalance Reserve — document bound, page for these figures not recorded
What it is for

Compensate resources positioned day ahead to preserve upward capability for forecast energy imbalance in real time.

Notes from the source

EIR began with DASI on 2025-03-01 and is distinct from ten- and thirty-minute contingency reserve.

What the source does not state

It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Ten-Minute Non-Spinning Reserve TMNSR Response type post-contingency Trigger qualified capability able to start, synchronize, and reach the reserve amount within ten minutes; participates in both day-ahead and real-time reserve procurement Dispatched by ISO New England instruction Expected within 10 min Through day-ahead; real-time Pricing design day-ahead or real-time reserve clearing price, as applicable
Full record for Ten-Minute Non-Spinning Reserve — document bound, page for these figures not recorded
What it is for

Provide qualified non-synchronized contingency response to replace the first resource contingency.

Checkpoint recap

Expected within 10 min

What the source does not state

The source states the response deadline. It does not state how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Ten-Minute Spinning Reserve TMSR Response type post-contingency Trigger online synchronized capability deliverable within ten minutes; participates in both day-ahead and real-time reserve procurement Dispatched by automatic response and ISO New England instruction Expected within 10 min Through day-ahead; real-time Pricing design day-ahead or real-time reserve clearing price, as applicable
Full record for Ten-Minute Spinning Reserve — document bound, page for these figures not recorded
What it is for

Provide synchronized contingency response to replace the first resource contingency.

Checkpoint recap

Expected within 10 min

What the source does not state

The source states the response deadline. It does not state how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Replacement reserve
Thirty-Minute Operating Reserve TMOR Response type post-contingency Trigger qualified online or offline capability deliverable within thirty minutes; system requirements include additional reserve associated with one-half of the second-largest contingency, with locational requirements when needed Dispatched by ISO New England instruction Expected within 30 min Through day-ahead; real-time Pricing design day-ahead or real-time reserve clearing price, as applicable
Full record for Thirty-Minute Operating Reserve — document bound, page for these figures not recorded
What it is for

Provide replacement reserve within thirty minutes and support recovery for a second contingency.

Checkpoint recap

Expected within 30 min

What the source does not state

The source states the response deadline. It does not state how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Reactive power & voltage
Voltage Support Service Voltage Support Response type continuous or directed Trigger facility-specific voltage schedule and reactive capability Dispatched by automatic voltage control and ISO New England instruction Through tariff-based Pricing design tariff-defined compensation, not a co-optimized reserve price
Full record for Voltage Support Service — document bound, page for these figures not recorded
What it is for

Maintain voltage and reactive-power capability on the transmission system.

What the source does not state

It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Other services
Blackstart Service Blackstart Response type restoration Trigger restoration-plan and facility-specific capability Dispatched by ISO New England restoration instruction Through cost-of-service arrangement Pricing design tariff-defined cost recovery
Full record for Blackstart Service — document bound, page for these figures not recorded
What it is for

Start without external station power and support restoration of the New England transmission system.

What the source does not state

It does not state a response time or how long delivery has to be sustained, and the volume is either set per auction or not published as a standing figure — the source does not say which.

Sources
Getting paid to exist

Does ISO-NE have a capacity mechanism?

Yes — Forward Capacity Market is a central capacity market.

Forward Capacity Market

No primary Forward Capacity Auction was conducted in calendar 2025 because FCA 19 was delayed during the transition toward a prompt seasonal capacity design. Three annual and twelve monthly secondary reconfiguration-auction results published during 2025 are included below. FERC accepted the prompt-market design filing on 2026-03-30; the seasonal/accreditation reform track remained pending at the cutoff.

Unit of obligation
MW of capacity supply obligation
Auction held in 2025
Yes () — Dated from the publication of the auction results.
Where this comes from

Official sources

Rules

Service specification

Capacity-mechanism explainer

Capacity result

Current as of · from the Global Electricity Market Catalogue v1.2.0 (compiled to , CC BY 4.0, rendered here with wording edited for readability). Facts belong to the linked official authorities; verify the current rules before design or bidding decisions.

Questions

Common questions about ISO-NE

Who operates ISO-NE?
ISO New England operates ISO-NE, covering Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, United States.
Was a qualifying capacity event held in ISO-NE in 2025?
Yes. Forward Capacity Market: a qualifying 2025 event is recorded (2025-07-02). Dated from the publication of the auction results.
How is energy traded, priced and settled in ISO-NE?
ISO-NE: nodal energy and ancillary-services markets with a Forward Capacity Market transitioning toward a prompt seasonal design.
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