Elexon assurance of legacy Suppliers and agents during the transition to MHHS

The MHHS Programme is introducing changes for legacy Suppliers and agents to support the Migration of Metering System Identifiers (MSIDs) from legacy arrangements to MHHS. Reverse migration can take place during the migration period (from March 2025 onwards) where a customer has switched to a Supplier that is not yet MHHS Qualified.

Where can I see the detail of the changes?

These changes are set out in design documentation in the MHHS Programme’s Migration Design, which will be drafted into the Balancing and Settlement Code through the delivery of MHHS Programme Code Artefacts.

These Code Artefacts will come into force under the BSC at the Programme Milestone M8 (7 March 2025) and therefore all Suppliers and legacy Supplier Agents will need to have made changes to support MHHS Migration Design by this time.

There are no obligations on these legacy agents to qualify as part of the MHHS Programme activities. Therefore, Elexon is using existing Performance Assurance activities to gain assurance that these ‘legacy side’ changes to Supplier and Supplier Agents processes are complete.

Performance Assurance Techniques that Elexon will use

These are the current arrangements agreed by the Performance Assurance Board (PAB) and they may be revised.


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