Targeted Charging Review Implementation: FAQs and guidance


This page answers frequently asked questions (FAQs) about Ofgem’s Targeted Charging Review Implementation and how it relates to the large scale changes to Market Domain Data.

Background and testing

What is the Targeted Charging Review?

The Targeted Charging Review: Significant Code Review is an Ofgem led project that assessed how residual network charges should be set and recovered in Great Britain by Licensed Distribution System Operators (Distributor Network Operators and Independent Distribution Network Operators and the National Electricity Transmission System Operator (NETSO).

How is Elexon supporting the implementation of the Targeted Charging Review?

In order to implement the Targeted Charging Review: Significant Code Review, Distributor Network Operators need to add a significant number of new Line Loss Factor Classes and valid set combinations into the Market Domain Database. These will be used to identify how Metering Systems are treated under the new network charging categories under the Targeted Charging Review.

Elexon administers the processes for making changes to Market Doman Data. It has been working with the Energy Networks Association and the Distribution System Operators to plan and support the raising of Market Domain Database Change Requests.

Elexon is testing Central Systems, why?

The Licensed Distribution System Operators need to more than double the number of Line Loss Factor Classes in Market Doman Data. The unprecedented growth in the size of the Market Doman Data and Line Loss Factor datasets presents challenges for Elexon’s Central Systems – in the first instance, the new Line Loss Factor Classes and valid set combinations simply need to be added to Market Doman Data and the LLF dataset, and communicated to Parties and Party Agents; Central Systems and participants’ systems must then receive, process and send larger dataflows and datasets caused by the growth in Line Loss Factor Classes and valid set combinations.

There is a risk that Central Systems and Participants’ systems might be impacted by the growth in Line Loss Factor Classes and valid set combinations. This is a risk factor for industry processes, for example Imbalance Settlement.

Between December 2020 and March 2021, Elexon is testing the resilience of Central Systems, so any weaknesses can be identified and managed before the much larger Independent Distribution Network Operators Market Doman Data Change Requests are processed.

As part of its Central System testing, between 10 and 23 February 2021, Elexon is making test files available to enable market participants to perform their own testing.

Where can I find more information about the Targeted Charging Review Testing for Market Doman Data and Line Loss Factor Class files?

More information is listed in the Circular below – including the dates, where the data files will be available and how to raise a defect .

Will there be support provided throughout the testing?

Yes, we have scheduled online drop-in sessions throughout the testing period and details will be shared with the testers.

What is the expected increase to file sizes as a result of the Targeted Charging Review?

The exact file sizes for Market Doman Data and Line Loss Factor files are not known until Central System testing has been carried out and the final submissions of Market Doman Data Change Requests have been submitted by the Independent Distribution Network Operators. The test files will be increased from approximately 19,000 to eventually include approximately 35,000 Line Loss Factor Classes.

What is the current planned Migration for the Targeted Charging Review?

Once LLFCs and reference data are added to Market Doman Data, as part of the Targeted Charging Review Licensed Distribution System Operators must update approximately 2m Metering System Registration Details in SMRS by moving them to a new Targeted Charging Review LLFCs, for example.

I am receiving a validation error when loading test D0265 flows, what should I do?

Depending on the type of validation performed by your system, the test files may require clock change details and settlement day details for 01 April 2021 to 31 March 2022.

This data is published in the D0269, but the data for 01 April 2021 to 31 March 2022 is not included in the files for Industry testing as the data has only become available in the Live MDD v307 for March 2021. The Live MDD v307 publish is in progress and we have extracted the clock change (from the CTC group in the D0269) and the settlement day data (from the SDT group in the D0269) in the attached two text files. If needed, please use these files to manually update your standing data.

Suppliers and Supplier Agents

Will there be other data flows impacted outside of the files produced by Elexon (Market Doman Data and Line Loss Factor Classes)?


The Line Loss Factor Class (D0265) and Market Doman Data (D0269 and D0270) are reference data needed to enable the Targeted Charging Review. To provide assurance to the BSC Panel and Supplier Volume Allocation Group (SVG) that systems can cope with this increase in data, Elexon is performing Central System Testing and Industry wide testing. However in addition to the aforementioned flows there are a number of data flows listed below that report data by Line Loss Factor Classes:

Some of these flows may be impacted by the volume of Line Loss Factor Classes within the files but the frequency will remain the same, for example, Monthly Market Doman Data flows D0269, D0270 and other flows that would increase the volume of flows, for example, D0209 Instruction(s) to Non Half Hourly or Half Hourly Data Aggregator.

The migration exercise may also be impacting exception flows, for example D0023 – Failed Instructions if there is an increase in potential errors updating SMRS.

We strongly recommend that Parties carry out their own assessments on the impacts of the Targeted Charging Review on their business’ processes and systems, noting that changes may go beyond network charging and billing processes and systems.

Are there any plans to relax the compliance timelines related to the impacted processes?

There are no current plans to relax the BSCP Timelines for data flows related to the Targeted Charging Review – we will keep this under review with the relevant BSC Panel Committees under the Performance Assurance Framework.

Independent Distribution Network Operators 

What files do I need to submit for Market Doman Data and LLFs needed for Targeted Charging Review?

Separate processes and documents are required to update LLFs and Market Doman Data.

From an LLF point of view we will treat the Targeted Charging Review Submissions as part of the Mid-year submission therefore required files are BSCP128 Request template, E17, CSAD Appendix 05,section 2.2 & Appendix 10.

From an Market Doman Data point of view a BSCP509 Cover Form and Entity Forms E17, E55, E56 and E63 should be submitted in accordance with BSCP509.

Which Effective From Dates (EFD) and Effective To Dates (ETD) required within the submission files?

Please submit using the provisional dates of 01/04/2021-31/03/2022. All of the Independent Distribution Network Operator submissions for the Targeted Charging Review will be scheduled across Market Doman Data releases indicatively over Summer and Autumn period to limit the impact on other Parties. Elexon will continue to work with Independent Distribution Network Operators and Electricity Network Association to coordinate Market Doman Data Releases and Targeted Charging Review Migration.

Do I need to submit artificial data for the time being just to reflect the volume or it has to be the final data?

Submissions should reflect the latest accurate information, such as actual Line Loss Factor Classes and Combinations should be submitted with the actual volumes. The data submitted will be used to perform validations, schedule Market Doman Data releases and plan Migration Exercises.

Which resource would I need to take into account when listing out the latest valid Host LDSO_LLFC combinations?

Please use the latest Market Doman Data Version in order to refer to the valid Host LDSO_LLFC combination when submitting the mapping table (Request Template).

Ask a question

If you have a question that isn’t answered on this page then please email the MDD Co-ordinator.


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