Last update: 09/04/2025
Below, affected ISO New England (ISO-NE) participants can learn more about changes to existing systems and procedures related to the FERC Order No. 841: Day-Ahead State of Charge project. 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 announcements about readiness outlook summaries, project pages, and training, please subscribe to the Participant Readiness and ISO Training mailing lists in Ask ISO. Refer to the How to Manage Your Mailing Lists article for instructions.
The Federal Energy Regulatory Commission (FERC) issued Order No. 841: Day-Ahead State of Charge to enable electric storage resources to fully participate in the energy, capacity, and ancillary services markets. In response, ISO-NE will introduce new optional bidding parameters in the Day-Ahead Energy Market (DAM). These parameters will be available during the DAM window for the operating day of Jan. 2, 2026, to allow market participants to optimize their electric storage facilities (ESFs) based on their state of charge (SOC) and duration.
To manage these changes, ISO-NE is implementing new features within the ESF section of the eMarket platform.
ESF Daily Parameters and Hourly Updates
The ESF Daily Defaults tab will be renamed to ESF Default Parameters. This display will be updated to include a portfolio selector, the lead participant, and the individual assets of an ESF. Beginning with the DAM entry window for operating day Jan. 2, 2026, new and optional daily SOC parameters will be available for editing. The new default parameters are defined as follows:
A new Hourly Updates tab will be available for editing beginning with the 10-day DAM entry window for operating day Jan. 2, 2026. This feature will allow participants to override the default parameter values for a given ESF on an hourly basis. On this screen, participants can adjust the maximum SOC, minimum SOC, and round-trip efficiency for each hour. The new hourly values are defined as follows:
Together, these parameters provide a comprehensive view of an ESF's capabilities in the DAM, indicating both the total MWh available for injection onto the grid and the ESF's duration characteristics. The SOC for each hour is dynamically calculated based on the previous hour's SOC, adjusted by the scheduled megawatts (MWs) and the ESF's round-trip efficiency, while respecting the hourly maximum and minimum SOC constraints.
Portfolio Management for ESFs
In November, with the eMarket production environment code migration, market participants will be able to create and manage ESF portfolios on the new ESF Portfolio Manager tab. An ESF portfolio is required for participants to update the real-time efficiency (RTE) value in the ESF Default Parameters display, and to perform XML downloads in the eMarket user interface. Participants will also be able to view their calculated SOC by portfolio for each ESF for a given market day. Portfolios are not required for XML uploads.
Reserve Accounting Treatment
The reserve accounting treatment will ensure that reserves associated with the generator component of an ESF are sustainable for one hour. This will correct a situation where reserve capability is overstated on the generator when it has an energy charging award in the same hour. When implemented, the state of charge gained from charging the dispatchable asset-related demand (DARD) component of a storage resource during an hour cannot be used to cover the discharge award for the generator component during that same hour.
Implementation Timeline:
Affected market participants are required to take specific steps or adapt to changes in ISO-NE systems as described below. Participants 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 |
|---|---|---|
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Sandbox roles: October 2025 Production roles: November 2025 |
Customer and Asset Management System (CAMS) |
Security Administrators (SAs) may assign these existing CAMS user roles to view and edit ESF displays:
SAs may assign these existing CAMS user roles to view ESF displays:
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Beginning October 2025 Testing dates TBA |
eMarket Sandbox |
Simulated pre-DAM window: All participants’ application programming interfaces (APIs) will change with the addition of the new parameters. All participants should test their eMarket APIs in sandbox. Participants must create an ESF portfolio to update their RTE values and to test the XML format download. The new day-ahead state of charge displays are visible. Simulated DAM 10-day window: Participants test the new ESF default and hourly parameters. |
|
November 2025 |
eMarket Production |
All participants’ APIs change with this release. Using the updated exchange formats is required. Participants may create ESF portfolios which are required to update the RTE value on the ESF Daily Default display and to perform XML downloads. |
|
December 23, 2026 |
eMarket Production |
DAM bidding window opens for operating day Jan. 2, 2026. Participants may choose to submit the new, optional parameters into the DAM for operating day Jan. 2, 2025. |
ISO New England and GE Grid Solutions 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 |
|---|---|
|
Updated Dec. 31, 2024 |
Webex Training for Continuous Storage Facility Participation to support Order No. 841. (Originally presented Feb. 21, 2019.) |
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TBA |
New training resources begin rollout in mid-September 2025 |
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.
| DOCUMENT | NOTES (if necessary) |
|---|---|
|
eMarket User Guide |
To be updated for changes under the FERC Order No. 841: Day-Ahead State of Charge project. |
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eMarket Data Exchange Specification |
To add state of charge offer parameters. |
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eMarket Web Service Definition |
To add state of charge offer parameters. |
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eMarket High Level Changes |
Will summarize changes coming to eMarket. |
| DOCUMENT | NOTES (IF NECESSARY) |
|---|---|
| Transmission, Markets, and Services Tariff |
Market Rule 1 Sections
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7.2.3 Generator Assets
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OP 14—Technical Requirements for Generators, Demand Response Resources, Asset Related Demands and Alternative Technology Regulation Resources Section II.A Generator Defined |
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