Market-wide Half Hourly Settlement and the BSC


On this page you can find out about what Elexon is doing to ensure that Market-wide Half-Hourly Settlement (MHHS) is implemented smoothly across the Balancing and Settlement Code Central Systems.

How it relates to you

MHHS is one of the biggest changes to energy markets since retail competition was introduced in the late 1990s.

Elexon has been appointed by Ofgem as the MHHS Programme Manager. This role will involve managing the activity of around 180 organisations across the energy sector to implement MHHS. 

The MHHS Programme has been separated from Elexon’s other BSC activities.  This means that the Programme has separate decision-making processes, reporting and resources. As a general rule, colleagues
within Elexon are not able to work on both the MHHS. 

Guidance for the industry on the MHHS programme

The MHHS programme has a dedicated website that outlines the plans, events and outcomes of the programme.

MHHS at Elexon: The Helix Programme

In 2021, we began the Helix Programme to re-develop BSC Central Systems to support MHHS, and to re-engineer the accompanying processes and procedures which unlock the benefits of MHHS for Suppliers. 

This re-development is needed so that Central Systems can manage an exponential increase in the amount of half hourly data we will need to process once MHHS is implemented in October 2025.  Elexon, as an MHHS Programme participant through Helix, is treated the same as any other MHHS Programme participant, and does not have any undue, or unfair influence on the central programme

The Helix Programme impacts almost all areas of Elexon, with a requirement for transformation of a number of existing services. Those which are most affected are:

  • Settlement and Invoicing
  • Participant Management
  • Rules Management and Assurance.

Our current expectation is that:

  • 19 BSC Sections and 39 existing Code Subsidiary Documents will be impacted
  • Four new Balancing and Settlement Code Procedures (BSCPs) will need to be drafted (The BSCPs set out procedures that BSC Parties, including their Agents and Elexon, must follow for compliance
  • One new Service Description will need to be drafted (BSC Service Descriptions describe the service to be provided by the BSC Agents).

New BSC services to support MHHS

MHHS will require the creation of four new services . The new services were specified in the Ofgem-approved MHHS Target Operating Model. The TOM explains the set of services and Settlement arrangements required to deliver MHHS.  The new systems and the new service will be developed on our cloud platform Elexon Kinnect.

The three new systems to be developed are:

  • The Load Shaping Service which will calculate energy consumption and load shapes using validated actual Settlement Period level data. These robust consumption profiles will improve the information we provide Suppliers by enabling them to better predict their customers’ usage, and perform their associated balancing activities
  • Market-wide Data Service which will aggregate data for smart, non-smart, advanced and unmetered supplies for Imbalance Settlement and other purposes such as network charges and flexibility offerings. It will also calculate and apply Distribution Line Loss values to the data, enabling
    it to provide data for BSC Assurance purposes
  • Volume Allocation Service (VAS) which will use data from the MDS to calculate energy volumes for Balancing Mechanism Units. The VAS will replace the legacy Supplier Volume Allocation Agent (SVAA) The VAS feeds into shorter Settlement run times, allowing Suppliers to better manage their credit positions, and pass savings on to customers
  • Industry Standing Data – a system which will be an enhanced version of our Market Domain Data and Line Loss Factor services, but with fewer manual processes to maintain it. This will save both time and resources for BSC Parties and Elexon colleagues.

Background information

In 2017, energy regulator Ofgem announced a review on whether the whole electricity market (commercial as well as residential properties) should move to half-hourly Settlement. Ofgem’s consultation on its draft Impact Assessment identified the need for a delivery Market-wide Half Hourly Settlement Programme Manager, accountable to Ofgem for ensuring the successful implementation of MHHS.

MHHS explained

Kevin Spencer, Market Architect at Elexon, produced a the video in September 2020 that covers the settlement timetable and explains the new Target Operating Model.

Video Published: September 2020
Video Length: 23 mins


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