ACER Updates REMIT Reporting Guidance

On 26 March 2026, the pan-EU energy regulator ACER published updates to its Manual of Procedures (MoP) and related FAQs. These changes specifically target the reporting of inside information under Article 4 of REMIT.

This is the first update to this part of the MoP since April 2023 and the first to these FAQs since December 2024. These new versions represent a move towards aligning with future reporting requirements under the revised REMIT II Implementing Regulations, which are widely expected to be published soon.

Market participants have nine months to comply with this new guidance. The implementation deadline is December 2026.

Key Changes to the MoP on Data Reporting

The most significant updates appear in the track-changed Version 10 of the MoP. These revisions focus mainly on the “lifecycle” reporting of Urgent Market Messages (UMMs) and asset capacity reporting.

• UMM Lifecycle and Immutability Published UMMs are now fully immutable. Any update to an event requires a new UMM version with an identical "UMM Thread ID" but a new version number applied in an ascending sequence. The latest version is the only applicable record and must contain all current details.
• Event Status Updates The term "Inactive" identifies UMMs where the reported event occurred in the past. While UMMs should be updated to "Inactive" once an event terminates, it's not mandatory to publish a new version solely because a date has expired.
• Gas Unavailability Definitions Guidance for gas facilities defines "Planned" unavailabilities as programmed changes like maintenance. "Unplanned" unavailabilities refer to unexpected forced outages or limitations.
• Overlapping Events and Capacity. When multiple events affect one asset, Field (9) "Unavailable Capacity" only shows the capacity lost due to that specific event. Field (10) "Available Capacity" must reflect the actual remaining capacity of the asset after considering all overlapping events.
• Mandatory Identifiers Field (17) "Affected Asset or Unit EIC Code" is now mandatory. Market participants must identify the specific asset using a unique EIC. The system now also supports EIC codes for substations.

FAQ Revisions

The amended FAQs align with the MoP changes. They provide further detail on reporting "Dismissed" or "Inactive" statuses and clarify the distinction between event-specific unavailable capacity and total remaining available capacity.

RegTrail Commentary

Firms with REMIT inside information disclosure obligations should review their technical reporting and business processes immediately to identify any necessary adjustments. The transition to mandatory EIC codes and the strict requirements for UMM lifecycle updates may require system changes or staff training ahead of the December 2026 deadline.