Smell Gas? Call 0800 111 999
Electricity Emergency? Call 105
Suspect Energy Theft?
Register >
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors
Emergencies
Suspect Energy Theft?
Register >
Biogas for business - Hero Banner

Market Wide Half-Hourly Settlement
(MHHS)

What is the Market wide Half-Hourly Settlement Programme?

A bit of background. The electricity settlement arrangements in place today have existed since the 1990s, when market competition was introduced. If you are too young to remember, the electricity market opened up in two phases:

  1. Phase 1: The Industrial & Commercial sector went first. The large volumes of energy consumed and the relatively few number of meter points meant that Half Hourly metering and half-hourly settlement arrangements were in place from the beginning.
  2. Phase 2: When the domestic/small business sector opened up (i.e. the vast bulk of 33+ million meter points), it would have been cost-prohibitive to enforce half-hourly on everybody. A technical alternative had to be introduced. The solution was Non-Half Hourly Profiling (Profile 1, 2, 3, 4 etc…)

The reality is that for the vast majority of meter points, every half-hourly period is estimated. Estimates of usage are updated as and when meters are physically read, meaning that the current settlement process takes over a year to complete.

Technology has improved…

Since the late 1990s technology has moved on in terms of the number of meter points which are capable of recording at half-hourly intervals. This has been made possible by smart and advanced metering. In other words, unlike 30 years ago, half-hourly settlement is feasible for the majority of those domestic/small business meter points.  On the back of these factors, in 2017 Ofgem announced a review on whether the entire electricity market should move to Half-Hourly (HH), and in April 2021, decided to proceed with MHHS in light of the benefits it could be bring for consumers. Amongst other benefits, MHHS will:

 Allow the industry to gain timely insight into how much electricity is being used by consumers (and when), so that generators, suppliers and consumers can better understand, forecast and generate the volume of electricity necessary to satisfy demand.

The above will better facilitate the journey to net-zero, acting as a key enabler for smarter tariffs, encouraging consumers to change energy behaviours.

Left icon

What does the “Settlement” part of MHHS mean exactly

Right icon

Put simply, settlement is about working out how much electricity a generator has generated and how much electricity a supplier’s customers have consumed, and then comparing the generation/consumption to what the supplier and generator have traded in order to calculate imbalance charges.

But the MHHS Programme goes beyond settlement…it’s an overhaul of established processes, roles and national IT systems. MHHS will introduce reforms which will see familiar terms become redundant, including EAC, DC and Profile Class.

What is changing?

The operational practices and processes of all key parties that exist in today’s market (suppliers, Meter Operators (MOPs), Data Collectors (DCs), Data Aggregators (DAs)) contribute to a common goal – the ability to settle at half-hourly increments. This is why, in many ways, the term “settlement” is almost synonymous with the electricity retail market.

Today’s industry systems are old, with complex interactions and relationships. If all metering in GB became HH settled overnight, the existing national IT infrastructure would be severely strained.

Therefore, the MHHS Programme will introduce a new piece of national IT infrastructure, the Data Integration Platform (DIP). Just like we witnessed with the faster switching Programme, the DIP will be a new core IT system, processing market messages between all participants in near real time.

All existing electricity participants will have to interact with the DIP (either directly or indirectly) and, as such, will have to change their existing systems to comply with the new arrangements.

Eventually, quicker settlement run times will come into effect. For example, Initial Settlement (SF) will reduce from today’s 16 working days to 5-7 working days; and Final Settlement (RF) will reduce from today’s 14 months to 4 months.

What are Market Segments?

Market Segment categories have been introduced due to the redundancy of several legacy data items associated with consumption. These terms will eventually replace “NHH” (Non Half-Hourly) and “HH” (Half-Hourly) as we know today.

There are three segments:


Advanced: Represented by all legacy Half-Hourly meters (i.e. Profile 0) and a meter which has an Automated Meter Reader (AMR). Common to both meter types is that half-hourly data is collected for settlement purposes.

Smart/Traditional: Covers smart meters operated by the Smart DCC as well as dumb meters. Key to both meter types is the reliance on register level readings.

Unmetered: Unmetered supplies, e.g. streetlights, traffic signs, zebra crossings etc.

How do you move all 33 million+ MPANs into MHHS?

At its most simplistic level, every single MPAN in GB (33 million+), including all existing Half-Hourly Profile 0’s, will have to be processed by the new DIP.

The sheer amount of data processing required to service 33 million MPANs means that MHHS cannot go live overnight.  Instead, MHHS go-live will be phased, meaning that all parties, including CGP, will have to migrate their MPANS at some point over a predetermined period.

But before parties can migrate their portfolio of MPANs, they will need to qualify. CGP will commence its migration from the 31st July 2026, subject to qualification.

What is meant by qualify?

All parties (suppliers, MOPs etc) must be capable of demonstrating that their IT solutions and processes can interact with the DIP as well as legacy systems. Qualification is mandatory, if we do not qualify, then Ofgem may prevent a supplier from taking on new customers.

Myth Busting

Myth 1: All of our electricity portfolio will need a meter exchange to HH.

Answer: Not Exactly

All MPANS (traditional, smart, advanced and HH) will be migrated into the new world regardless of their meter type. The existing legal obligations placed on a supplier to upgrade dumb meters to smart/advanced continues today and beyond MHHS.

Myth 2: We will receive HH consumption data for all of our migrated meter points.

Answer: True.

This data is a reflection of what we as a supplier are settled on, but we won’t necessarily use it for billing.

Myth 3: All migrated customers will be billed to the HH consumption data that we receive.

Answer: Not exactly.

For those customers with advanced meters, we will indeed bill them using their consumption data. However, those customers with Smart and Traditional meter types will be billed on register reads (and settled on HH data) in a similar fashion today.

Myth 4: We don’t need to migrate our existing HH meters into the new world?

Answer: Myth.

We will have to migrate existing HH meter types into the new market arrangements.

Myth 5: All of our customers will have the same MHHS experience?

Answer: Myth.

There is no one-size-fits-all all experience. Whilst most of our changes will be back office (data-driven) there will be some customers that may ‘see’ more changes. For example, those customers Non-Half Hourly (NHH) customers with an AMR meter who are used to receiving bills based on register readings, will be automatically migrated into the Advanced Segment, and will be billing to half-hourly consumption data.

Myth 6: The EAC will become the Annual Consumption.

Answer: Myth.

Once migrated every MPAN will, at some point during the next 30 calendar days, will be provided with an Annual Consumption and a Quality indicator.

This Quality Indicator will be provided to show the basis of how the Annual Consumption has been derived. For example, an MPAN with 100% Actual Data will be categorized as “A”, an MPAN with greater than 75% of Actual data, would be graded with “1”, and so on.
On Day 1, there will be no historic consumption available in the DIP (and EAC’s will not be carried forward). As there is less than a full year’s worth of consumption data within the DIP for the MPAN our current understanding is that Quality Indicator for all Annual Consumptions will initially be assigned a grade 5 (less than 50% of data) or “D” (default).

Myth 7: The Profile Class and SSC will no longer be important.

Answer: Not exactly.

When an MPAN migrates into the DIP, the Profile and SSC are effectively “lifted and shifted” along with it. The MHHS regime no longer considers the PC and SSC as settlement related data. As such, the PC and SSC are effectively “labels” on EES, which will only be mandatory for Traditional meter types.

It is perfectly possible that for non-traditional meter types (Smart and Advanced), that you could see a difference between the Profile Class lasered on the top line of an S-Number of an invoice, compared to what is shown on EES. Suppliers do have the option of maintaining such values on EES (i.e. removing them from EES value to align with an invoice), although leaving them on EES does bring quoting benefits as, by its very nature, a Profile Class indicates how that MPAN will typically consume electricity.

What is happening from Autumn 2025 and what changes will we see?

From Autumn 2025 the MHHS Programme will move into an operational phase, and we will witness some consequential changes as a result. Key dates for the diary:

Top Line Changes: 22nd September 2025: Milestone 8

In September, the Top Line of a Supply Number (“S Number”) will be “tweaked” in preparation for MHHS go-live. This S-Number is typically printed on our invoices and itemised on quotations.

For many years, the Top Line has been made up of the following data elements, reading from left to right: Profile Type, Meter Time-Switch Code (MTC) and Line Loss Factor (LLF).

From 22th September 2025, the MTC will be replaced by the Standard Settlement Configuration (SSC), and the LLF will effectively be renamed as the DUoS Tariff ID.

What is the SSC? This is a four-digit code used to identify how a NHH meter is configured for settlement purposes. Specifically, it specifies the number of registers on the meter and the times at which electricity usage is recorded by each register. Any meter which is Half-Hourly (Profile 0) will have no SSC and will be represented as ‘0000’.  It is worth noting that when a Smart Meter Type is migrated into the new MHHS arrangements, the SSC will be represented as ‘0000’ and the corresponding Profile Class will be shown as ‘00’.

22nd October 2025: Milestone 11

From 22nd October 2025, the migration of MPANs into the DIP will commence. This date is known by the MHHS Programme as M11.

Electricity Enquiry Service (EES) (also known as ECOES)

The Electricity Enquiry Service will introduce a new suite of visual symbols to denote whether an MPAN has been migrated (or reverse migrated). EES will also display an MPANs Market Segment (Smart/Traditional or Advanced etc), Annual Consumption, and Customer owned contract information.

Reverse Migration

Between October 2025 and 31st July 2026 (the date when we anticipate to commence our migration), it is likely that we will inherit a MPAN which has already been migrated into the new MHHS world by the previous supplier.  Should we acquire such an MPAN during this period, we will have no option but to transform the MPAN back into ‘legacy mode’ under a process called ‘Reverse Migration’.

It is feasible that customers with an AMR meter, who have signed a historical NHH Supply Agreement with us, could be migrated into the Advanced segment before switching. In such situations, we will continue to honour the contracted rates of the original ‘NHH’ Supply Agreement.

What’s next?

The MHHS timeline runs well into 2027. All industry participants will follow individual schedules within this period, as set and coordinated by the MHHS Programme.

Migrating our entire electricity portfolio (from 31st July 2026) will take several months and will depend on several factors, including the number of MPANs in a given DNO and the type of meter being migrated.

Business Energy

Utility Connections

Support

Contact Us

Crown Gas & Power
Crown Point
Heap Brow
Bury
BL9 7JR
United Kingdom

Tel: 0161 762 7744
Email: hello@crowngasandpower.co.uk

Accreditations

Iso Logo
Iso Logo
Iso Logo

© 2025 Crown Gas & Power. All rights reserved

Crown Gas & Power is a commercial energy supplier, who have been supplying gas to UK businesses since 2001. We are renowned for our personalised service, competitive prices & variable length supply contracts. Our service also includes utility connections & service alterations for gas, electricity & water.