MHHS Code Change and Development Group (ceased)

The  MHHS Code Change and Development Group (CCDG) is one of three industry working groups which Elexon is chairing and providing with technical leadership to support Ofgem’s Significant Code Review on Electricity Settlement Reform.

This Working Group has ceased. The content on this page is for archive reference only. Further information about from the following web pages:

CCDG’s role, outputs and timetable

The CCDG is building on the Target Operating Model (TOM) for Market-wide Half Hourly Settlement (MHHS), as delivered by the Design Working Group in August 2019, by:

  • Developing further detailed areas of the TOM design
  • Developing further detail on the transition approach for migrating different types of Meters to the new Settlement arrangements, and on the ‘run-off’ of the existing Non Half Hourly Settlement arrangements
  • Identifying, and overseeing drafting of, the changes needed to Industry Codes and key subsidiary documents to enable the TOM

The diagram below shows when the CCDG plans to consult industry for the different stages of its work, as well as when it intends to issue its final report to Ofgem. We are currently reviewing the timing of these milestones alongside Ofgem’s wider MHHS Programme planning.

For each CCDG meeting, we produce a Headline Report summarising its discussions (see ‘Meetings’ below). Since March 2020, the CCDG has been meeting remotely.

What’s new?

Thank you to everyone who responded to the CCDG’s recent consultation on the lower-level areas of the TOM design and the changes that the CCDG believes will be required to Industry Codes. You can find copies of all the public consultation responses under ‘Related Content’.

What are the CCDG’s main conclusions from the consultation?

The CCDG is encouraged that the responses confirm that its design work is consistent with the overall TOM and that it has captured all major changes to Industry Codes.

The CCDG’s key conclusions are that it:

  • Will revisit whether any changes are needed to the design or transition approach for its new appointments process, after the Architecture Working Group (AWG) has consulted on its recommended reference architecture (see ‘next steps’ below)
  • Recognises its omission of some TOM data items which will be corrected in the master list included in the AWG’s consultation
  • Will keep the ability to have Related Meters (MPANs)
  • Confirms that the TOM will not have a Settlement volume correction process for Erroneous Transfers
  • Will keep all existing BSC data items until the end of transition to the TOM, after which any no longer needed for Settlement may move to another Industry Code
  • Notes that Ofgem is leading discussions with the Smart Energy Code and the Data and Communications Company on their technical solution to deliver the TOM

You can find more information in the CCDG’s Meeting 14 and Meeting 15 Headline Reports.

What are the next steps?

The CCDG recognises that its work so far is not the complete picture of the TOM and that more details will become clear in:

  • The AWG’s consultation on reference architecture (in Spring 2021, register for the webinar here)
  • The CCDG’s consultation on its transition approach for migrating different types of Meters from the old to the new Settlement arrangements (in Summer 2021)
  • The CCDG’s consultation on the redlined changes to Industry Codes (in 2022)

Ofgem will consider any confidential information provided by respondents as well as comments on areas that fall outside the CCDG’s remit.

The CCDG looks forward to continuing to engage with you as its work progresses.


2021 CCDG meeting dates

Meeting number

Papers published

Meeting date


11 January 2021

19 January 2021


8 February 2021

16 February 2021


8 March 2021

16 March 2021


12 April 2021

20 April 2021


10 May 2021

18 May 2021


7 June 2021

15 June 2021


12 July 2021

20 July 2021


9 August 2021

17 August 2021


13 September 2021

21 September 2021


11 October 2021

19 October 2021


8 November 2021

16 November 2021



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