December 15, 2025

The AESO is currently finalizing revisions to the proposed REM ISO rules in response to stakeholder feedback and anticipates the Government will create the regulation required for Ministerial approval of the REM ISO rules soon.

In its engagement materials, the AESO advised stakeholders that it would post revisions to the proposed REM ISO rules, together with the responses to stakeholder feedback, in December 2025. However, the AESO is now advising stakeholders that the revised REM ISO rules and response to feedback will instead be posted early in 2026, after the regulation for approval of the REM ISO rules has been released. At the same time, the AESO will release other supporting documents, including the third party report it has commissioned from ECCO International for an independent evaluation of the REM ISO rules with the REM final design.

For those market participants previously deemed eligible for Funding for Participation in REM Engagements, the posting of the REM ISO rules will mark the completion of stakeholder engagement. Once posted, eligible market participants will have 30 days to provide supporting documentation described in the AESO Process - Funding for REM Engagement Participation.

October 15, 2025

On October 9, 2025, the AESO hosted a hybrid technical session with stakeholders to discuss and resolve outstanding questions regarding the proposed REM ISO rules. The technical session addressed topics related to the proposed REM ISO rules based on comments received from stakeholders on the AESO’s Stakeholder Engagement question board. A Technical Session Summary has been posted.

September 10, 2025

There was an issue identified with the Blackline posted on September 4. We have corrected it and a revised version has been posted. While the issue only substantively impacted one REM ISO rule, Section 212.8, Issuing Dispatches and Directives for Operative Reserves, other minor formatting related issues with track changes were found and corrected in the new version. If you had already downloaded a copy of the Blacklines, please replace with the new one. Thank you for your understanding.

September 8, 2025

We are aware of an issue with the Blackline for at least one section of the rules. We are actively investigating and working to correct it. We will repost a new version of the Blackline document as soon as possible. Thank you for your patience and apologies for any inconvenience.

September 4, 2025

On September 4, 2025, the AESO hosted a virtual information session where the final REM design updates were discussed. In addition, the REM ISO rules engagement process, approval process and timeline, a summary of the changes to the ISO rulebook, and the next steps for engagement were reviewed.

To assist in the engagement process, the following documents have been released for stakeholder review:

• Proposed REM ISO rules
• Rule Reference Document
• Table of Concordance
• Definitions Document
• Blacklines