MDD changes initiated by Ofgem Review


Large scale changes to Market Domain Data (MDD) based on Ofgem’s Targeted Charging Review (TCR).

This page contains details about the planned increase of MDD sets in response to Ofgem’s TCR and how this will impact BSC Parties. You can also find out information about why these changes are happening, what has already happened and what the next steps are.

Latest updates

11 January 2021

Industry testing confirmed for w/c 8 February 2021

We can confirm that industry testing, in support our continuing work to progress large scale change to Market Domain Data (MDD) sets for Ofgem’s TCR, will now take place between 10 February 2021 to the 23 February 2021.

The testing is expected to take a day or two.

Thank you to everyone who has registered their interest in participating in testing. If you haven’t yet but would like to, please contact the Release team by 15 January 2021.

January data set to be published on 13 January 2021

On 13 January 2021 we will publish a large MDD set, which includes several of the Distributed Network Operator (DNO) changes required to meet Ofgem’s Targeted Charging Review (TCR) requirements. The data set includes the TCR changes for the remaining Host Distributed Network Operators DNOs and includes 13 out of 14 Grid Supply Point (GSP) Groups.

This data set will go live on 20 January 2021.

If you experience any unexpected system issues, or have questions relating to the January data set, please contact the MDD Coordinator.

December data set went live on 16 December 2020

We published the December MDD data set on Wednesday 9 December 2020, which went live on Wednesday 16 December 2020. This published data set did not contain any TCR changes. We will continue to monitor the progress of the MDD published for December and listen to feedback from parties.

If you experienced any unexpected system issues, please contact the MDD Coordinator so we can investigate.

IDNO Change Requests

We will continue to validate Independent Distribution Network Operator (IDNO) Change Requests for the time being, and will seek approval from the SVG to progress these after we have completed industry testing.

IDNO workshop to discuss progress and timescales

On Monday 14 December 2020 we held a workshop with IDNOs to discuss the number of LLFC combinations being requested, and to explain how the MDD processes and timescales work.

We will continue to supporting the IDNOs with their submissions following this workshop.

Latest Panel update

On 10 December 2020 we provided the BSC Panel with an update on progress with regards to the changes to MDD, as well as the associated risks and mitigations, and proposed next steps.

The Panel paper provides further information.

How it relates to you

Ofgem’s TCR means major changes to how network charges are set. It will see the numbers of LLFCs in MDD increasing on a large scale, as well as the number of valid set combinations.

BSC Parties who load MDD and LLF files may be impacted, as they will have to load significantly larger numbers of new LLFCs and valid set combinations.

Such a large increase in data could impact your network systems. If you notice any such impact, please contact the MDD Coordinator or LLF Coordinator.

Next steps

Industry Testing

Test plans will incorporate testing for Participants, the BSC Central Systems, and subsequent Settlement processes as they will be using the increased volumes of LLFCs. We will provide you with a further update on the test plan as soon as we can.

We will make sure that the participants are kept informed with regards to testing and are provided with sufficient notice prior to TCR submission dates.

Reasons for testing

As this is a major change to MDD data, Elexon has been leading work to carry out central system testing and participant testing. Overall we will need to provide assurances to the SVG, the BSC Panel and BSC Parties that adding such a large amount of new data will not pose risks to Settlement.

Software development

Automatically loading MDD

Software is being developed that will automatically load MDD, as this is currently a manual process. This should reduce the risks around the publication and data quality of MDD for participants.

What’s already happened

Publishing data

  • 9 December 2020: MDD data set was published, but the set did not contain any TCR changes. This went live on 16 December 2020.
  • 11 November 2020: 1,638 new LLFCs and 37,000 new valid set combinations added to MDD. This went live on 18 November 2020. 
  • 14 October 2020: 2,122 new LLFCs and 24,287 new valid set combinations added to MDD. This went live on 21 October 2020.

This new published data impacts D0269/D0270 (MDD) and D0265 (LLFC) flows.

Previous news

Why these changes are happening

Ofgem’s TCR addressed concerns that the current framework for residual network charges could lead to inefficient use of the network. This means there will be major changes to how network charges are set.

This will result in the numbers of LLFCs in MDD increasing from 16,000 to approximately 35,000. The number of valid set combinations will also increase from around 208,000 to approximately 470,000.

The distribution charge aspects of Ofgem’s reforms will be introduced from April 2022.


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