As part of the UK energy industries journey towards a smarter and more precise settlement process a key change is coming into effect this autumn. The UK electricity supply number format changes will be effective from the 22nd of September 2025, Although this is largely cosmetic to business owners, this is a crucial step in preparing for the new market-wide half-hourly settlement (MHHS) system which promises more accurate, efficient electricity settlement by December 2026.
What Are Supply Number Format Changes (R0083)?
The Supply Number Format Changes (R0083) project will see the traditional top line of the supply number change.
The Meter Timeswitch Code (MTC) will be replaced by the Standard Settlement Configuration (SC) ID and the Line Loss Factor Class (LLFC) will be renamed to be called the DUoS Tariff ID. There will be no changes to the Profile Class ID.
Please see image below:

What’s the Timeline?
The change is tied to the MHHS programme milestone 8, with the changes expected to go live on the 22nd September 2025. This aligns with the broader MHHS changes, which is expected to be implemented across the energy industry by December 2026.
As part of the Supply Number Changes, all bills or annual statements produced from the go live date of 22nd September 2025 will be updated to reflect the new format.
Why Does It Matter?
Whilst these changes may just seem like a simple label change, they actually play a vital role in preparing the UK energy market for the future. As previously mentioned, the intended purpose of these changes is to lay the groundwork for the MHHS programme rolling out in December 2026. This reform is all about improving accuracy and consistency in how energy usage is recorded and billed.
For businesses this means:
Clearer Data: The updated fields (SSC & DUoS Tariff ID) make supply information easier to understand and make it standardised across the industry.
Foundations for MHHS: Accurate supply numbers are essential for half hourly settlement which will eventually bring fairer and more accurate billing, smarter energy usage and a more flexible electricity system.
Smooth switching and quoting: Energy suppliers and brokers will be working from the same updated data, reducing errors and speeding up process.
What Will Change for Businesses?
For the majority of businesses these changes are purely cosmetic and do not require any action from your side. However, these may be a few things you may notice:
New Labels On Contracts, Invoices, And Bills: The Meter Point Administration Number (MPAN) will see the ‘MTC’ and ‘LLFC’ replaced wit the Supply Segment Code (SSC) and DUoS Tariff ID. This will not affect your rates, but the terminology will look different.
Simpler Supply Identification: The updated format will make it easier for energy suppliers and brokers to identify your site accurately, reducing the chance of errors when switching or updating accounts.
In short, these changes are largely behind the scenes and businesses will not need to take any action, your energy supplier will handle the transition automatically. Moving forwards into the future, once fully adopted the new structure will support MHHS and other initiatives like flexible tariffs or energy management tools, which could help business with optimising their energy consumption.
Final Thoughts
While the Supply Number Format changes are mostly behind-the-scenes, they mark an important step toward a smarter, more efficient UK energy market.
By standardising supply data, the industry is paving the way for Market-Wide Half-Hourly Settlement (MHHS), improved accuracy in billing, and better tools for businesses to manage energy use.
For now, no action is required but staying informed ensures your business is ready to take full advantage of the benefits these changes will bring in the years ahead.
For further information regarding these changes head over to the Ofgem website here.
To keep up to date with all updates around the MHHS rollout you access the dedicated website here.