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MHHS Changes:
7 changes you need to know abut Market-wide Half Hourly Settlement


Market-wide Half Hourly Settlement (MHHS) aims to provide everyone who uses electricity with actual half-hourly data.

That means we all benefit from better billing, settlement, decarbonisation and energy cost-saving opportunities, at work or home. 

However, MHHS changes can be confusing. 

It’s being implemented by Elexon, the UK agency managing the settlement processes between suppliers, generators and traders of electricity. 

The timescale for MHHS is October 2026, with many new processes and demands on all industry participants, including Network, Metering and Data providers. 

Businesses will need to stay up to date with how the landscape will change, and that’s where we come in.  We are slap-bang in the middle of it all. 

Whilst our technology teams get our systems ready, let’s look at 7 key changes MHHS will have on us all. 

MHHS change 1: Centralisation

The most fundamental change is increased centralisation, with Elexon receiving meter-level HH data and performing market-wide aggregation itself.  

For example, we currently perform Data Aggregation services as a competitive agent. This will change under MHHS as Elexon centralises that function. 

Pro: More energy data & insight for all

Con: Risk of reduced service quality and innovation

MHHS change 2: New role established to maintain customer choice of SMETS or Advanced meter types

Currently, it is difficult for organisations that are independent of your supplier to collect all the data required for settlement from SMETS meters. 

That’s because the Data Communications Company (DCC) is a centralised monopoly that handles access control and data retrieval from SMETS meters. 

A new DCC User Role called the Meter Data Retriever (MDR) is being created under MHHS that will enable organisations like us to collect data for settlement independently of your supplier.  

This gives you the same level of choice and service for customers with SMETS meters as those with Advanced meters. 

Pro: Independent assurance of the SMETS meter data

Con: Data access may not be equal between users

MHHS change 3: The electricity market will be split by Meter Type instead of Non-Half Hourly (NHH) or Half-Hourly (HH) 

Non-Half Hourly and Half-Hourly both describe ways your electricity consumption can be accounted for and settled. They’re known as settlement types. 

Under MHHS, the market will no longer be segmented by these well-known settlement types. 

Instead, it will be segmented by meter type, specifically Smart meters (SMETS1 or SMETS2) or Advanced meters. 

You may have a mix of SMETS, Advanced and Traditional/dumb meters in your portfolio. 

This will mean you’ll end up with a mix of Centrally collected data for your smart meters, and your Advanced meters collected by your preferred agent, like us. 

The UK market size for each meter type

SMETS & Traditional meters

Domestic & Microbusinesses



I&C and SME




Streetlights etc


Pro: Choose your specialist meter & data partners

Con: Traditional meters are included in the Smart segment which doesn’t quite add up

MHHS change 4: A new, faster requirement for data 

Changes under MHHS include changes to the timetable for complete data collection. Which means faster fault fixing by meter operators.  

These changes to the settlement timetable by Elexon mean that everything must be done faster, with less opportunity for correction later.  

This will hopefully drive all agents to get it right the first time more often, which means better, more complete data for customers.  


Pro: Meter faults must be fixed faster and data processed faster

Con: Undetected settlement errors won’t always be fixed

MHHS change 5: Lots of new terminology to learn 

Anything HH or NHH will disappear. That’s the big change most business customers will see who are used to contracting or analysing energy metering and data. 

There is plenty of new terminology to learn, and we’ll help you through that. We’ll be updating our website and Glossary so you can stay up to date. 

But for now, some of the main ones which will affect all data customers are: 

  1. Meter Operator becomes Metering Services 
  2. Data Collector becomes Data Services 
  3. Data Aggregation becomes Market-wide data service (centralised) 

Pro: Clearer definition of roles

Con: New roles for customers to understand

MHHS change 6: New load shaping to replace NHH profiles

A new central “load shaping service” will continue to create profiles to settle any remaining Traditional meters or opted-out domestic customers. 

This means not all of the market will end up half-hourly settled using actual data, but at least there’s a mechanism to handle it. 

Pro: Mechanism for settlement & estimating data

Con: Not all of the market will be half-hourly settled

MHHS change 7: A new way to get your MOP & DC appointments  

Currently, suppliers send appointment notices for HH and NHH meters directly to the Meter Operators and Data Collectors, then separately update the relevant Registration service. 

Under MHHS suppliers will tell the relevant Registration Service who the appointed agents should be, and then they will notify the Metering and Data service agents.  

Pro: A sole source of truth for appointments and registration data

Con: Potential over-reliance on the Registration Services

MHHS changes will provide a flexible smart grid for the future, made up of SMETS and Advanced meters across the domestic and business sectors.

But the transition will be full of changes which we will all need to get to grips with.   

We will be on hand throughout keeping you up to speed, so make sure to sign up for emails or contact us to discuss your meter and data needs.


Watch the full EMEX presentation from our Head of Policy on MHHS

Watch now


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Home » MHHS | 7 changes you need to know | Market-wide Half Hourly Settlement