Market-wide Half-Hourly Settlement (MHHS)

• MHHS: An Overview
• The benefits of MHHS
• The impact to customers

What is Market-wide Half-Hourly Settlement (MHHS)?

MHHS stands for Market-wide Half-Hourly Settlement. It’s a UK-wide energy industry change mandated by Ofgem, to modernise how electricity usage is processed, and is part of a wider project to digitise the energy industry. Previously the way consumption data was recorded by meters was segmented into Half-Hourly (HH) and Non-Half Hourly (NHH) categories. This will now change, so that all settlement of consumption will be done half-hourly (every 30 minutes).   

The new market segments for meters will be Smart, Advanced and Unmetered. Smart includes both traditional and smart meters, while Advanced is composed of Advanced Meters (AMRs).

While the majority of changes will happen behind the scenes, we will contact affected customers with more information closer to the time.

What are the benefits of MHHS?

The benefits for customers include:

• More accurate billing
• Better visibility of energy usage
• In the longer term the market developing tailored products 

More widely, it will also support the UK’s Net Zero goals, supporting the transition to decarbonisation, as well as the wider energy strategy improving the expansion of smart meters and consumer choice. This will:

• Help to encourage innovation to support a smarter and more flexible electricity system
• Ensure future energy system is affordable for consumers by reducing waste
• Act as an enabler for new products and services. For example, supporting use of electric vehicles or making use of smart appliances through ‘time of use’ tariffs (where consumers save money if they shift their energy usage away from peak demand times) 

Why is MHHS important?

• Greater Visibility of Consumption Data 
  MHHS will enable access to more granular consumption data, which will replace existing estimated profiles with actual usage, allowing more accurate forecasting of energy needs.
• Supports Sustainability Goals
  Half-hourly settlement enables better integration of renewable energy and demand-side flexibility, helping businesses contribute to a greener grid and meet net-zero targets.
• Market Innovation
  MHHS opens the door, in the longer term, to new products and services, such as time-of-use pricing and tailored energy solutions, giving businesses more choice and control.
• Regulatory Compliance
  This change is mandated by Ofgem and is part of the UK’s transition to a smarter, low-carbon energy system. Being prepared ensures your business stays compliant and competitive.

Will MHHS affect me as a customer?

The changes are focused on how suppliers settle energy usage with the grid. You won’t notice any difference in your service or contract. In the long term, you may have the opportunity to benefit from smarter tariffs.

Do I have to switch to MHHS?

Yes, all electricity customers will move to MHHS as part of a regulatory change led by Ofgem.

SEFE Energy will transition as part of the national migration window running from October 2025 to May 2027. 

Do I need to do anything?

No action is required from you. SEFE Energy will manage the transition and the majority of changes will happen behind the scenes. If you don’t yet have a smart or advanced meter, we may contact you to arrange an upgrade. Upgrading can help benefit more from MHHS, although it is not required. 

Will my invoice change?

Some of the technical codes shown on your contract changed as part of the MHHS programme. 

A new topline format now applies on invoices across the industry from the 22nd September 2025. This is the information contained in the S number which is included on your invoice. This information is important to your energy supplier to help us identify what meter configuration you have, but you don’t need to do anything regarding this. You can see what it will now look like below.

What if I don't have a smart meter / do I need to get a smart meter?

While there is no requirement to have a smart meter for MHHS, it is highly recommended to upgrade to a smart meter to gain the full benefit of MHHS. All customers, regardless of meter type, will be treated as a half-hourly customer.

If you are one of many larger businesses with either a transformer or a power capacity exceeding 100kVA, an Automated Meter Reading (AMR) meter can be installed.

You can find out more useful information on the Market-wide Half-Hourly Settlement update and what this means for businesses below: