By Steve Heathcock
Understanding the Transition, the Risks, and the Practical Solutions Available
The UK electricity market is entering one of the most significant periods of structural change since deregulation. Market-Wide Half-Hourly Settlement (MHHS) will fundamentally alter how electricity consumption is measured, settled and billed for every electricity customer in Great Britain.
While MHHS is often described as a technical or regulatory reform, its implications extend far beyond industry systems and processes. It will influence how electricity is priced, how risk is allocated, how data is accessed, and how organisations understand and manage their energy use. Over the next 18–24 months, organisations that engage early with the MHHS transition will be far better positioned to manage cost, reduce risk and improve insight. Those that delay may find themselves reacting to supplier-led decisions with limited flexibility, reduced transparency and fewer commercial options.
This article provides a detailed update on the MHHS transition, explains what is changing and why it matters, and outlines how Auditel – working with specialist partners such as TMA – is supporting organisations through the transition with practical, future-ready solutions.
WHY MHHS IS HAPPENING NOW
Electricity has been traded in the wholesale market on a half-hourly basis for many years. However, the way most customers have historically been settled has not reflected this reality.
The majority of non-domestic customers have traditionally been settled on a Non-Half-Hourly (NHH) basis, often using estimated consumption profiles combined with periodic meter readings. These profiles smooth demand across a theoretical day rather than reflecting real operational behaviour, meaning that two organisations with very different usage patterns can be settled in broadly the same way.
While this approach has been workable in a more stable energy system, it is increasingly misaligned with today’s market. The growth of renewable generation, the electrification of transport and heating, and the increasing importance of demand flexibility all require more accurate, time-based data.
MHHS addresses this mismatch by moving all customers to settlement based on actual half-hourly consumption data, captured directly from smart and advanced meters. This aligns settlement with wholesale trading and network charging, and provides the foundation for a more flexible, responsive and transparent electricity system.
FROM ESTIMATED PROFILES TO REAL BEHAVIOUR
One of the most significant changes under MHHS is the move away from estimated profiles towards settlement based on real consumption behaviour.
Under the existing system, peak demand, overnight usage and changes in operating hours may not be fully reflected in settlement calculations. This can mask inefficiencies and distort pricing outcomes.
MHHS introduces settlement that reflects when electricity is consumed, how demand varies throughout the day, and how closely usage aligns with system peaks. For some organisations this creates opportunity, particularly where demand can be managed or shifted. For others, MHHS may expose inefficiencies that were previously hidden.
Either way, the change places far greater emphasis on understanding consumption behaviour – not just annual consumption volumes.
WHAT THE MHHS TRANSITION CHANGES IN PRACTICE
Although MHHS is delivered through industry systems, its effects will be felt directly by organisations.
Pricing Based on Load Shape
As settlement becomes more granular, suppliers will increasingly price electricity based on a customer’s load shape rather than broad profile classes. Two sites with similar annual consumption may see very different pricing outcomes depending on when energy is used.
Meters that are not MHHS-ready will rely on load-shaping services instead of actual data. Over time, this is widely expected to lead to less competitive pricing compared to sites settled on real half-hourly data.
Data as a Strategic Asset
Half-hourly settlement requires consistent, high-quality data. This creates a step change in the availability and usefulness of information, supporting improved budgeting, forecasting, identification of inefficiencies, carbon reporting, and compliance with frameworks such as ESOS.
For many organisations, MHHS will highlight gaps in data quality and visibility that were previously masked by estimated settlement.
Enabling Future Energy Strategies
Time-of-use tariffs, electric vehicle charging optimisation, battery storage and demand-side response all rely on half-hourly data. MHHS provides the settlement framework that allows these products to operate effectively at scale.
WHERE THE INDUSTRY IS NOW: KEY TRANSITION MILESTONES
The MHHS programme is already underway, but the transition is phased and supplier-led. This means that not all organisations will migrate at the same time.
Key milestones include:
January 2025 – Industry testing continues
June 2025 – Radio Teleswitch (RTS) switch-off, requiring upgrades for affected meters
September 2025 – MPAN profile changes begin
October 2025 – Supplier-led migration begins for early adopters
December 2025 – Increasing risk to 2G and 3G smart meter connectivity
May 2027 – Deadline for all customers to be migrated where required
July 2027 – Full transition to the new settlement timetable
While traditional meters will continue to be supported in principle, manual meter reads are expected to become more frequent and more expensive, making them a less attractive option over time.
METERING: FROM BACKGROUND UTILITY TO CRITICAL ASSET
Historically, metering has often been treated as a background utility – something that sits quietly behind the scenes.
Under MHHS, this changes significantly. Metering becomes a data-critical asset, with connectivity, maintenance and data quality directly influencing settlement accuracy and pricing outcomes.
Many organisations have limited visibility of their current metering arrangements, which are often bundled into supply contracts and managed by suppliers. MHHS places renewed importance on understanding and actively managing these arrangements.
Organisations should be considering whether their meters are MHHS-ready, whether they have reliable access to consumption data, and how resilient their metering arrangements are to future market change.
WHAT ORGANISATIONS SHOULD BE THINKING ABOUT NOW
As the MHHS transition gathers pace, organisations should be asking several strategic questions.
Do we understand when our energy is used, not just how much?
How exposed are we to pricing based on load shape?
Are our metering arrangements future-proof?
How much control do we have over data access and quality?
These are not purely technical questions. They affect procurement outcomes, budget certainty and long-term energy strategy.
HOW AUDITEL AND TMA SUPPORT THE MHHS TRANSITION
Auditel’s role during the MHHS transition is to help organisations understand change, manage risk and make informed decisions.
This includes translating MHHS from industry language into practical implications, supporting clients to assess how settlement changes may affect pricing and procurement outcomes, and reviewing metering arrangements as part of wider energy strategy discussions.
Where appropriate, Auditel works with specialist metering and data partners, including TMA, to ensure organisations have access to practical, compliant and future-ready solutions that support half-hourly settlement and reliable data access.
MHHS AS AN OPPORTUNITY, NOT JUST COMPLIANCE
Although MHHS is a mandated industry change, it should not be viewed solely as a compliance exercise.
For organisations that engage early, MHHS offers the opportunity to improve visibility of energy use, align pricing more closely with operational behaviour, strengthen sustainability reporting, and build a more resilient energy strategy.
Those that delay may find their options narrowing as suppliers, systems and processes adapt around them.
FINAL THOUGHTS
MHHS represents the most fundamental change to electricity settlement in a generation. It introduces complexity, but also the opportunity for better data, better decisions and better outcomes.
The organisations that will benefit most are those that treat MHHS as part of a broader energy and data strategy, supported by expert advice and practical solutions, rather than a technical migration to be dealt with at the last minute.
