Market-wide Half Hourly Settlement Update
Further to our previous news items on this significant industry change, published on 2 September 2024 (UK Market-Wide Half Hourly Settlement | NUS Consulting) and 23 January 2025 (Market-wide Half Hourly Settlement Update - Jan. 2025 | NUS Consulting), we are providing a further update on this major UK energy industry programme.
Recent Key Development
Effective 22 September 2025, the top line of all Meter Point Administration Numbers (MPANs) has been updated as part of the transition towards Market-Wide Half-Hourly Settlement (MHHS).
An MPAN is the unique reference used in Great Britain to identify an electricity supply pointโoften referred to as a Supply Number or S-Numberโand is displayed on all electricity invoices.
The top line of the MPAN (previously a 21-digit sequence, now 22 digits) identifies key characteristics of the electricity supply, such as the profile class and line loss factor.
This is simply an administrative change, and no customer action needs to be taken.
From 1st October 2025, the first wave of migration began. This will initially involve customers supplied by Pozitive Energy, Npower and SE. We will cover more on the migration timeline later in this briefing.
About the MHHS Programme
The Market-Wide Half-Hourly Settlement (MHHS) programme extends the half-hourly electricity settlement process to all meters, including those previously settled on a non-half-hourly basis.
This reform enables energy suppliers to reconcile, on a half-hourly basis, the difference between electricity purchased and electricity consumedโdelivering greater accuracy, transparency, and efficiency across the market.
The programme will involve 30 million meters, including domestic premises; however, it is anticipated that most AMR meters will be able to switch over to Half-Hourly (HH) data without being exchanged, therefore minimising operational disruption.
What Has Changed?
The previous MPAN top line contained the following fields:
- Profile Type
- Meter Time-Switch Code (MTC)
- Line Loss Factor (LLF)
From September 2025, these fields are updated as follows:
- MTC โ replaced by Standard Settlement Configuration (SSC)
- LLF โ renamed as DUoS Tariff ID
Understanding the Standard Settlement Configuration (SSC)
The SSC is a four-digit code that identifies how a non-half-hourly meter is configured for settlement purposes. It specifies the number of registers on the meter and the time periods when electricity usage is recorded by each register.
- Half-hourly meters (Profile 0) will have no SSC and will be represented as 0000.
- When a smart meter is migrated into the new MHHS framework, the SSC will also be represented as 0000, and the corresponding Profile Class will be displayed as 00.
Once the migration is complete, Profile Classes will be withdrawn, except for Classes 02 and 04, which will continue to identify Economy 7 and Economy 10 meters respectively.
Terminology Updates
The MHHS programme introduces a refreshed terminology framework across metering and data services:
| Previous Term | New Term |
|---|---|
| HH/NHH Data Collector (HH DC/NHH DC) | Advanced Data Services (ADS)/Smart Data Services (SDS) |
| HH/NHH Meter Operator (HH MOP/NHH MOP) | Metering Services Advanced (MSA)/Meter Services Smart (MSS) |
| Meter Operator (MOP) | Meter Operating Agent (MOA) |
| AMR (Advanced Meter Reading) | Preferred Technology for seamless MHH migration |
Migration Timeline
The transition to MHHS will occur in phased waves between September 2025 and July 2027:
- September 2025 โ Industry systems go live
- October 2025 โ May 2027 โ Industry migration window
- October 2026 โ Supplier qualification deadline (Suppliers must be MHHS-compliant to continue signing new business)
- July 2027 โ Ofgemโs target date for full MHHS completion
Supplier Migration Waves
| Wave 1 | Wave 2 | Wave 3 | Wave 4 |
|---|---|---|---|
| Pozitive Energy | Engie | Drax Power | Bryt Energy |
| Npower | EDF Energy | Smartest Power | Brook Green |
| SSE | Corona |
How NUS Consulting Can Support Your Business
NUS Consulting is committed to ensuring our clientsโ electricity portfolios are fully MHHS-ready. We offer strategic and operational support across the following key areas:
- Non-Compliant Meter Identification โ Detect and prioritise meters that are non-functional, non-communicating, or incapable of half-hourly data transmission.
- Quality Assurance for Installations โ Ensure all new installations meet the MHHS readiness standards (e.g., SMETS2 or AMR with communications).
Through these actions, we help clients maintain compliance, enhance data integrity, and optimise operational performance.
Contact Us
For further guidance on MHHS readiness or to schedule a portfolio audit, please contact your Consultant, or contact us online.