What it is, why it's happening and how it might impact you
What is MHHS?
Market-wide Half-Hourly Settlement (MHHS) is a major transformation of the UK electricity market that changes how electricity consumption is measured. The transition is based around the installation of smart meters and uses actual electricity usage data recorded in 30-minute intervals, allowing energy suppliers to more accurately match the electricity purchased with the electricity their customers use. Led by MHHS and supported by Ofgem, the programme applies to both domestic and business electricity customers across Great Britain.
The result? More accurate bills for customers and a more competitive market with a greater variation of products available.
Why is MHHS happening?
MHHS is being introduced to create a smarter, more efficient and more flexible energy system that supports the UK’s ever changing energy demands. By using more accurate consumption data, suppliers can better understand when electricity is being used and provide products that encourage customers to shift demand away from peak periods. This helps reduce overall system costs, makes better use of renewable energy generation, and enables innovative tariffs and services, such as time-of-use tariffs. Ofgem estimates that MHHS could deliver substantial consumer benefits through a more efficient energy market and lower system costs over the long term.
What does MHHS mean for customers?
For most customers, MHHS will be a behind-the-scenes industry change with no disruption to their energy supply. The main impact will depend on your meter type. Customers with AMR meters will move to billing based on actual electricity usage rather than periodic meter readings. Further information on this can be found below.
Customers with Smart meters will unlock many of the benefits the programme is designed to deliver, this may support more accurate billing, better visibility of energy usage and access to new tariff options over time. In most cases, customers will not need to take any action, and any affected customers will be contacted directly if required.
What is changing?
The MHHS transition has been implemented in such a way to minimise any direct impact to customers, however, the type of meter you have at your property will influence what benefits you might gain from the transition and if anything changes for you.
MHHS impacts by meter type:
Customers who agree a contract for an electricity supply with YGP who have an AMR meter, on or after the 17th of October, the supply will join as an MHHS setup and bills will be billed to half-hourly energy consumption, not meter readings.
Customers who agreed a contract for an electricity supply with YGP who have an AMR meter, before the 17th October and the supply is not yet live with YGP, the supply will either join as MHHS setup or be moved to MHHS setup before March 2027.
Bills before an MHHS setup will be to meter readings, bills once in an MHHS setup will be to actual energy consumption.
Customers with an electricity supply that is already live with YGP, the supply will be moved to MHHS setup between October 2026 & March 2027 and we will contact you closer to the time.
Most AMR meters can provide half-hourly consumption data remotely, subject to having a working communications connection. Under the new industry arrangements, your bill will be calculated using this consumption data, providing a more accurate reflection of the energy used during the billing period.
What MHHS means for you
- Access to more detailed energy consumption information through your customer portal (where data is available).
- Bills based on actual energy usage, helping to improve billing accuracy.
If your meter cannot provide remote usage data
Where we are unable to receive actual half-hourly consumption data from your AMR meter, your bill will be based on estimated half-hourly consumption data calculated using industry-held information.
If you would prefer your bills to be based on actual energy consumption, you may need to arrange for any communication issues affecting our meter to be investigated. In some cases, it may be necessary to replace your existing AMR meter with a smart meter.
We will contact customers whose meters require replacement to ensure they can continue to receive bills based on actual energy consumption.
There will be no significant impact.
MHHS centres around using half-hourly consumption data to improve the accuracy of bills and give both suppliers and consumers a greater understanding of peak usage times and total energy use.
If you have a smart meter, you’ll largely be unaffected by MHHS, but in the mid to long term you’ll start seeing a greater variation of products available and you’ll benefit the most from MHHS implementation.
- You’ll continue to see detailed usage information on your portal and be able to download half-hourly usage data.
- You’ll continue to receive bills to meter readings that we remotely access each month, saving you having to remember to submit meter readings each month.
- In future, you’ll see a greater variety of products available that will more accurately fit the needs of your business.
The above benefits will only be applicable for smart meters that we are able to connect to and obtain the accurate data. If you have a smart meter and are not seeing accurate reads on your bill each month, please contact us and we can investigate.
These meters cannot provide half-hourly consumption data for settlement purposes and do not automatically send meter readings to us. To take full advantage of the benefits introduced through Market-wide Half-Hourly Settlement (MHHS), you will need to upgrade to a smart meter.
What MHHS Means for You
- Upgrade to a Smart Meter
- To benefit from the changes being introduced under MHHS, you’ll need a smart meter that can record and securely share half-hourly consumption data.
- We’ll be contacting eligible customers to discuss a meter upgrade. In most cases, smart meter installations are provided at no additional cost. Installation is straightforward and typically results in a short interruption to your electricity supply, often lasting between 30 and 60 minutes.
- No changes to your billing – Your billing arrangements will remain the same and even when you upgrade your meter, you’ll still be billed to meter readings.
- Continue Submitting Meter Readings – You’ll still need to provide regular meter readings through the customer portal or YGP app to help ensure your bills are as accurate as possible.
Request A Smart Installation
- Email us at contact@ygp.co.uk
- We will work with you and our trusted metering partner SMS to get you a smart meter installed as smoothly as possible.
Why Upgrade?
A smart meter can help you:
- Access more detailed information about your energy usage.
- Benefit from bills based on actual consumption data.
- Reduce the need to submit manual meter readings.
- Gain greater visibility and control over your energy consumption.
Customers with Half-hourly meters already see the benefits of billing using half-hourly data, but there are some small things that will change.
What MHHS means for you
- If your bill includes Meter Operator (MOP), Data Collector (DC) and/or Data Aggregator (DA) charges, these will be replaced with the new roles of Meter Services (MS) and Data Services (DS) – your charges will remain the same.
- If you have your own MOP/DA/DC agreement(s), you’ll need to ensure that the agreement covers the transition to MHHS and that your provider is a qualified MHHS participant. If they are not, we will appoint our own qualified MS/DS agents when your supply is moved over to the MHHS setup and charges will apply.
What isn’t changing?
There will be no impact on your current contracted rates or any interruption to your energy supply as part of the MHHS implementation.
Learn more about MHHS
For more detailed information on the MHHS transition, visit the MHHS Programme Website for programme updates and guidance, or explore Ofgem’s MHHS Resources for industry news, articles, and regulatory information.
Frequently asked questions
The first MHHS rollout began in September 2025 with customer migrations taking place through to May 2027 and is being introduced in stages across the energy industry.
The full transition is expected to be complete by July 2027, when all suppliers will use half-hourly electricity consumption data for settlements.
Most customers will not need to take any action as part of the migration, we will contact you with further information and guidance.
For most businesses, MHHS will have very little impact on day-to-day operations.
By using more detailed energy consumption data, MHHS aims to create a more efficient and responsive energy market. This could help businesses benefit from:
- Bills that more closely reflect actual energy usage
- A clearer understanding of when electricity is being consumed
- More opportunities to improve energy efficiency and reduce waste
- New tariff and flexibility options as the market develops
Businesses with smart or advanced meters are best placed to benefit from these changes, as they can automatically provide the half-hourly data needed for MHHS. If you don’t have a smart meter, contact us to get one installed.
To gain the benefits introduced by the MHHS transition, you’ll need a meter that is capable of capturing half hourly data – these are Smart, AMR and Half-hourly meters.
If you don’t have a smart meter, or if there are any communication issues, you will need to get a smart meter installed to see the benefits of MHHS. Not sure what type of Meter you have? – You can log on to the YGP app or portal to find out: my.ygp.co.uk
Smart meter installations are straightforward, and eligible businesses may be able to receive an upgrade at no additional cost. If a smart meter upgrade is recommended for your premises, we’ll be in touch to discuss options available.
You will be moved across to MHHS regardless of whether you have a smart or advanced meter, but without one you may not benefit fully from the changes. Upgrading to a smart meter can help you get the most from MHHS, with automatic meter readings, more accurate billing, and better insight into when and how your businesses use energy.
Smart meter installations are straightforward, and eligible businesses may be able to receive an upgrade at no additional cost. If a smart meter upgrade is recommended for your premises, we’ll be in touch to discuss options available.
If you’d like to arrange a smart meter installation, simply email us at contact@ygp.co.uk. We’ll arrange your installation and help you through the process from start to finish. Once installed, a smart meter can automatically provide meter readings, support accurate billing, and help you get the most from changes such as MHHS.
For most customers, there will be little or no change to their bills as a result of MHHS. Your contract, agreed rates, and payment arrangements will remain unchanged throughout your contract term.
The actual impact of MHHS may vary depending on the type of meter you have. For information specific to your meter type, please refer to the section above. Not sure what type of Meter you have? – You can log on to the YGP app or portal to find out: my.ygp.co.uk
Where smart or advanced meter data is available, MHHS can help improve billing accuracy by using more detailed electricity consumption data. You may also notice minor updates to the information or format displayed on your bill as industry systems evolve. We’ll communicate any changes in advance and provide support throughout the transition.
No, MHHS will not increase your energy prices or change your agreed contract rates. For most business, there will be little or no impact on day-to-day billing.
If you have a smart or traditional meter there will be no impact, you will continue to receive bills to reads. If you have an AMR meter we will contact you directly to explain what changes after your supply is moved across to MHHS. There will be no interruption to your energy supply during the migration process.
The actions you need to take will depend on the type of meter you have:
- Smart Meter – No action is required. Your meter will continue to provide the data needed for MHHS automatically.
- Traditional Meter (non-smart) – To get the full benefits of MHHS, we recommend upgrading to a smart meter. Please contact us to discuss a smart meter installation at contact@ygp.co.uk
- AMR Meter – Continue providing regular meter readings, including before your migration to MHHS. If your meter is no longer communicating, we recommend upgrading to a smart meter. Please contact us to arrange an installation at contact@ygp.co.uk
- Half-Hourly (HH) Meter with your own MOP, DA and DC agreements: You should review your existing agreements to ensure they cover the replacement Metering Service (MS) and Data Service (DS) arrangements introduced under MHHS.
No, your energy supply will not be interrupted as part of the MHHS migration process. The change takes place behind the scenes, so you’ll continue to receive energy as normal.
MHHS is a UK energy industry requirement, so businesses cannot opt out of the programme. All electricity suppliers will be moving customers to the new market arrangements as MHHS is implemented across the industry.
No. All energy suppliers are required to move eligible supplies into the MHHS framework as part of an industry-wide change. Switching supplier will not exempt your business from MHHS, as all suppliers will ultimately operate under the same market arrangements.
