Day-Ahead Ancillary Services Initiative (DASI)

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Last update: 03/11/2025

Below, affected 黑料网 (ISO-NE) participants can learn more about changes to existing systems and procedures related to the Day-Ahead Ancillary Services Initiative (DASI). This project is one of several that ISO-NE has undertaken, in collaboration with stakeholders, for the continued development of the region’s wholesale electricity markets.

See the Participant Readiness Project Outlook for a summary of specifically affected participants and systems for this and other major projects. To receive outlook and project page announcements and training notices, please subscribe to the Participant Readiness and ISO Training mailing lists, which can be managed in Ask ISO. Refer to the article for instructions.

Project Overview
Required Participant Actions
Participant Training Opportunities
Technical Documentation, Rules, and Procedures
Project Development Materials

Project Overview

黑料网 will introduce ancillary services and constraints in the Day-Ahead Market (DAM) for operating date March 1, 2025, to develop a day-ahead operating plan that satisfies both the load forecast and contingency reserve requirements. Participants with generators, demand response resources (DRRs), or dispatchable asset-related demand (DARDs) that want to provide ancillary services will be required to bid into the DAM to offer these services.

With the introduction of the day-ahead ancillary services, the Forward Reserve Market (FRM) will be retired. The last FRM period is October 1, 2024 to February 28, 2025. The last valid contract date for FRM contracts is February 28, 2025. The Internal Transactions user interface and upload process will return an error message if a contract date exceeds the FRM sunset.

Two new ancillary services categories will be offered in the DAM to provide visibility and compensation to resources fulfilling contingency reserve and reliability requirements, thereby improving DAM pricing and preparations by resource owners to ensure availability.

Flexible response services (FRS) are analogous to the 10-minute spinning reserves (TMSR), 10-minute non-spinning reserves (TMNSR), and 30-minute operating reserves (TMOR). All three represent fast-start or fast-ramping capabilities to aid in the recovery from the loss of large transmission or generation facilities.
Energy imbalance reserves (EIR) are a new product that will allow 黑料网 to call on resources to operate above their day-ahead energy schedule when there is a need to bridge a gap between the day-ahead cleared supply and forecast demand.

A new constraint will be introduced and existing constraints will be enforced in the day-ahead security-constrained unit commitment (DASCUC) and day-ahead security-constrained economic dispatch (DASCED) processes.

A new forecast energy requirement (FER) will be enforced in both the DASCUC and DASCED to ensure that physical suppliers clear a sufficient amount of energy and EIR offers to satisfy the load forecast in the DAM.
The 10-minute spinning reserve, 10-minute reserve, minimum total reserve, and total reserve constraints will be enforced in both the DASCED and DASCUC.

A new Forecast Energy Requirement Price (FERP) is the clearing price for the FER (analogous to how the LMP is the clearing price for the energy balance constraint). A MWh of cleared day-ahead energy from a physical supply resource will be paid the locational marginal price (LMP) + FERP, because that MWh contributes to both the energy balance and FER constraints. A MWh of cleared EIR, in contrast, is paid only the FERP, because it contributes to the FER, but not to the energy balance constraint.

Participants with generators, DRRs, or DARDs that will provide FRS or EIR must submit ancillary services offers for their resources with the maximum MWh values they are willing to provide and the minimum price they must receive to clear in the DAM. The price and quantity pairs are submitted for a specific hour, or range of hours, and can vary by hour.

Participants can also opt to provide a maximum daily award limit (MDAL) to indicate the maximum total energy and ancillary services MWhs a resource can clear over the 24-hour DAM horizon. The MDAL is similar to the maximum daily energy (MDE) offer parameter in that it represents the total energy MWhs available for a resource on an operating day. Participants can provide the MDAL and MDE parameters, one or the other, or neither.

Required Participant Actions

Affected market participants are required to take specific steps or adapt to changes in ISO-NE systems as described below, and should be mindful of additional time-bound items, some of which may require participants to take specific steps or adapt to changes in ISO-NE systems both before and after the project implementation date.

TIMING OR DEADLINE	SYSTEM	ACTION OR EVENT
July 2024	Internal Transactions	The forward reserve ten minute non-spinning reserve (TMNSR) and the forward reserve ten minute operating reserve (TMOR) can only be selected for contracts with start and end dates before March 1, 2025.
November 19, 2024	eMarket Sandbox	For operating day November 21, 2024 and later, participants can test submitting benchmark limit data, daily total MWh limits, and day-ahead ancillary services offer price and quantity pairs by the hour or for a range of hours. They can view a new eMarket display for hourly strike prices and expected closeouts. eMarket data exchange specifications can also be tested.
February 20, 2025 to February 28, 2025	iso-ne.com Calendar	A strike price table will be posted for viewing until the automated strike pricing mechanism is activated with the project go-live. Check the iso-ne.com calendar for an 8:00 a.m. notice with a link to the data each day or sign up for the All Notices or Market Notices mailing lists to receive an email when the table is available. Refer to the article for instructions.
February 20, 2025	iso-ne.com	A monthly Day-Ahead Ancillary Services Monthly Real-Time LMP Modeling Memo will be located in the Ancillary Services section of the Pricing Reports in ISO Express to update participants with the retrained statistical model for forecasting real-time locational marginal prices (RT LPMs).
February 28, 2025	iso-ne.com	Participants begin to review the Day-Ahead Ancillary Services Strike Price report and the Day-Ahead Hourly Reserve Requirements, Prices, Designations, and Forecast report to be posted to the 黑料网 website after the DAM close. Location will be communicated when determined.
February 28, 2025	eMarket Production	Participants submit benchmark limit data, daily total MWh limits and day-ahead ancillary services offer price and quantity pairs by the hour or range of hours for operating day March 1, 2025. They can view hourly strike prices and expected closeouts in a new eMarket display and begin to use their updated eMarket data exchange specifications, if applicable.
March 1, 2025	Financial Assurance Management (FAM)	Day-ahead ancillary services reserve requirements are included in the financial assurance (FA) calculation.
February 28, 2025	Web Publishing	The new day-ahead ancillary services values are available.
February 28, 2025	Market Information Server (MIS)	New and updated settlement reports to be available. Reports will also be retired.
After March 2026	Forward Reserve Market Auction	The auction software will remain on the SMD Application Home Page until sometime after March 2026 in the event there is a resettlement.
After March 2026	Forward Reserve Assignment	The assignment user interface will remain on the SMD Application Home Page until sometime after March 2026 in the event there is a resettlement.

Participant Training Opportunities

黑料网 may offer online or classroom-based training, information sessions, and other opportunities for affected customers to learn about changes and ask questions in advance of project implementation.

DATE	EVENT AND SUPPORTING MATERIALS
Beginning August 2024, through Q1 2025	Access the to view released training modules. Stakeholders may opt to receive notifications when new content is released by clicking the blue follow button at the top right of the playlist landing page. Planned and released training modules include: Offer Inputs Offer Formation Mitigation Market Clearing Settlements —a supplemental reference for the self-paced training
April 10, 2025, time and registration information TBA	In-person session to discuss the new Day-Ahead Ancillary Services Market. Subject matter experts will be available to discuss market participation and key observations. Questions may be submitted through Monday, March 24, 2025, in Ask ISO with the with the subject “DA-AS Session”.
February 12, 2025, 1:00 p.m. ET	Day-Ahead Ancillary Services Training Webinar Forum–This webinar features experts from 黑料网 as they review key questions and answers to help participants navigate Day-Ahead Ancillary Services. Recording
February 19, 2025	Day-Ahead Ancillary Services Q&A Forum Knowledge Articles–A four-part series of questions and answers from the Day-Ahead Ancillary Services Training Webinar Forum.
March 6, 2025	Day-Ahead Ancillary Services Settlement Reference Guide–This guide features four hypothetical day-ahead ancillary services offering scenarios, how each offer settles in relation to their DA and RT energy offers and performance, as well as changes in the actual RT Hub LMP. Day-Ahead Ancillary Services Settlement Reference Guide (handout)– Printable handout of the DA A/S Settlement Reference Guide table that illustrates the outcomes of four hypothetical offer scenarios.
February 21, 2025	Day-Ahead Ancillary Services (DA A/S, DASI) Knowledge Check–25 multiple-choice questions about the Day-Ahead Ancillary Services Market to help participants identify topics they may need to learn more about.

Technical Documentation, Rules, and Procedures

Market participants affected by the project should consult the following documents for specific instructions on completing related tasks or processes and helpful answers to frequently asked questions.

Technical Specifications and Documentation

DOCUMENT	NOTES (if necessary)
Web Services End Point List	Web Services list updated with DASI end points.
eMarket Web Services API	XML and ISON Web Services formats for RESTful interface to energy and market data.
	eMarket Web Service Definition v25 WSDL and XSD updated for DASI.
eMarket User Guide	User Guide version V8.0 updated for DASI.
eMarket Data Exchange Specification	eMarket Data Exchange Specification v12.0 updated for DASI.
DASI eMarket High-Level Changes	Summary of changes made for the obligation for ancillary services to bid in the Day-Ahead Market.
New reports	Day-Ahead Ancillary Services MIS reports effective March 1, 2025: : Day Ahead Cleared Ancillary Services Settlement Report : Day Ahead Ancillary Services Settlement Detail Report : Day Ahead Ancillary Services Settlement Detail Subaccount Report : Day Ahead Ancillary Services Settlement Summary Report : Day Ahead Ancillary Services Settlement Summary Subaccount Report Reserves MIS reports effective March 1, 2025: : Reserve Detail Five Minute Report : Reserve Detail Five Minute Subaccount Report : Reserve Market Customer Charges Report : Reserve Market Customer Charges Subaccount Report : Reserve Market Settlement Report : Reserve Market Settlement Subaccount Report
Modified reports	Day-Ahead NCPC MIS reports effective March 1, 2025: SD_DANCPCDARD: Day-Ahead DARD Commitment Report SD_DANCPCDARDSUB: Day-Ahead DARD Commitment Subaccount Report SD_DANCPCDRR: Day-Ahead NCPC Demand Response Resource Commitment and Dispatch Report SD_DANCPCDRRSUB: Day-Ahead NCPC Demand Response Resource Commitment and Dispatch Subaccount Report SD_DANCPCGEN: Day-Ahead Generator Commitment and Dispatch Report SD_DANCPCGENSUB: Day-Ahead Generator Commitment and Dispatch Subaccount Report SD_DANCPCPYMT: Day-Ahead Net Commitment Period Compensation Payment Report SD_DANCPCPYMTSUB: Day-Ahead Net Commitment Period Compensation Payment Subaccount Report Real-Time NCPC MIS reports effective March 1, 2025: SD_RTNCPCHS: RT NCPC Hourly Shortfall Payment Report SD_RTNCPCHSSUB: RT NCPC Hourly Shortfall Payment Subaccount Report SD_RTNCPCHSDRR: Real-Time Net Commitment Period Compensation Demand Response Resource Hourly Shortfall Payment Report SD_RTNCPCHSDRRSUB: Real-Time Net Commitment Period Compensation Demand Response Resource Hourly Shortfall Payment Subaccount Report Other affected MIS reports effective March 1, 2025: BL_DETAILS: Bill Details/Adjustment Detail Report BL_DETAILSSUB: Subaccount Bill Details/Adjustment Report – for INFORMATION ONLY BL_SUBDETAILS: Subaccount Bill Details/Adjustment Detail Report
Reports to be retired	FRM MIS Reports: SD_RSVASTDTL – Reserve Asset Detail Report SD_RSVDTL5MIN - Reserve Detail Five-Minute Report SD_RSVTRANSACT - Forward Reserve Transaction Activity Report SD_RSVCHARGE - Reserve Market Customer Charges Report SR_RSVSTL - Reserve Market Settlement Report SR_RSVZONESUM - Reserve Market Zonal Summary Report

Rules and Procedures

DOCUMENT	NOTES (if necessary)
Section III Market Rule 1 Appendix A (redline)	Section III.A.3.3 Market Participant Access to its Reference Levels and Day-Ahead Ancillary Services Benchmark Levels
OP-14 Appendix E	Explanation of Terms and Instructions for Data Preparation of 黑料网 Form NX-12E, Asset Related Demands Technical Data
Manual 11 Redlines	Market Operations Manual redlines for DASI
Manual 11	Market Operations Manual Revision 62 (DASI Final)
Manual 28 Redlines	Accounting Manual redlines for DASI
Manual 28	Accounting Manual Revision 65 (DASI Final)

Project Development Materials

ER24-275-000, FERC Order Accepting the Day-Ahead Ancillary Services Initiative
Day Ahead Ancillary Services committee presentations and FERC filings and orders NEPOOL technical committee materials for participants and stakeholders, related FERC documentation.
Day-Ahead Ancillary Services Initiative Key Project page