Transition Design

Transition Design is split into two tranches:

Tranche 1 consists of elements that impact a Party’s near term Design Build and Test (DBT) activity, including:

• Parallel Running and Grid Supply Point (GSP) Group Correction
• Transitional Interfaces
• Transition Approach and Requirements: Line Loss Factors (LLFs) and Unmetered Suppliers (UMS) Charge Code and Switch Regimes

Tranche 2 relates to the Governance and Transition to new timetables and includes:

• Transition Approach and Requirements: Supplier Volume Allocation Agent (SVAA), Settlement Administration Agent (SAA) Calendars and Master Settlement Timetable
• Transition to the new Settlement Timetable

Transition Design Artefacts updated following Change Request CR055

Following approval of CR055: Amendments to M10 and Corresponding Milestones, the Settlement Timetable Requirements Artefact timelines need to be updated to reflect the new milestone dates.  

We requested industry input to confirm that they agree with the updates to the following Artefacts, which you can view in the  Transition Design Tranche 2 Artefacts library below.

• MHHS-DEL1590: Transition to new Settlement Timetable V2.3 
• MHHS-DEL1593: Replacement RF Settlement Timetable RF Illustration v1.1

This consultation has now closed. Thank you to everyone who responded. 

The Programme is reviewing the comments and, if relevant, we'll update the Artefacts. The updated Artefacts will be discussed at the Transition & Operational Readiness Working Group (TORWG) on Wednesday 16 April 2025, before going to the Migration & Cutover Advisory Group on Tuesday 29 April 2025 for approval.

If you have any questions, please email Transitiondesign@mhhsprogramme.co.uk    

Transition Design Tranche 2: Artefacts Baselined

The Programme published the Settlement Timetable Transition Solution for consultation, which closed on 25 October 2023. 

The solution will reduce the current 14-month settlement window, to four months, to align with the new MHHS Target Operating Model on the M16 milestone cutover date (7 December 2026). The solution also caters for a fall back timetable, if the M16 date needs to be deferred.   

You can view the Transition Design Tranche 2 Consolidated Comments Log below:

Transition Design Tranche 2 Consolidated Comments Log

The Artefacts were approved and baselined at the Design Advisory Group (DAG) on 8 November 2023.  

If you have any questions, please email TransitionDesign@mhhsprogramme.co.uk

Transition Design Tranche 1: Baselined Artefacts  

Thank you to all participants who reviewed and provided input on Tranche 1 of the Transition Design Artefacts.

These Artefacts were discussed in collaboration with the Migration and Transition Design Subgroup (MTDSG) and were published for review and comment on  14 April 2023. The comment window for Tranche 1 closed on 28 April 2023. ​​​

Following review of the comments and feedback provided, we have published the updated Transition Approach and Parallel Running Requirements and Provisional Transitional Scaling Weights Artefacts in the library below. The Transitional BMU Aggregated Data Artefact has not had any material updates made to the document, and so remains as the same version.

We have also published the updated Transition Design Consolidated Comments Log which you can access below:

Transition Design Tranche 1 Consolidated Comments Log

The Artefacts were baselined at the Design Advisory Group (DAG) on 14 June 2023. 

If you have any questions, or you need further information, please email Design@mhhsprogramme.co.uk