Market wide half hourly settlement (MHHS)
What's MHHS?
MHHS is a significant regulatory change for the UK energy industry that modernises the measurement, trading and settlement of electricity. Ofgem aims to create a more efficient, transparent, and sustainable energy system that helps the UK meet its net zero targets.
Benefits of MHHS
Market wide half hourly settlement will provide accurate meter readings in the UK by recording the Half-Hourly (HH) data that modern electricity meters produce - including smart devices.
Accurate billing
Half Hourly power consumption delivers accurate billing data
Insight into energy usage
Analyse your energy data and optimise
Net zero
Support UK’s net zero goals
Flexibility
Participate in demand-side flexibility services
Find out more about MHHS
What’s the Market-wide Half Hourly Settlement and what does it mean for businesses?
The UK energy system is undergoing one of its most significant changes in decades - the introduction of Market-wide Half -Hourly Settlement (MHHS).
MHHS – making smart choices
Unsure if you should do anything to prepare for MHHS? Will having a traditional (non-smart) meter be a disadvantage?
Why you should care about the Market-wide Half Hourly Settlement
For many customers, most of the MHHS action and change is occurring behind the scenes. It’s suppliers and their agents altering processes and systems, or dealing with new data flows, as Ofgem has mandated.
What does the Market-wide Half Hourly Settlement mean for me?
As we transition to a smarter, cleaner, and more efficient energy system, what does MHHS mean for your business?
FAQs
What is Market-wide Half-Hourly Settlement (MHHS)?
The UK energy regulator, Ofgem, has initiated a significant regulatory change for the industry in the form of Market-wide Half Hourly Settlement (MHHS).
By modernising the measurement, trading and settlement of electricity, Ofgem aims to create a more efficient, transparent, and sustainable energy system that helps the UK meet its net zero targets.
When’s the MHHS roll out happening?
MHHS is taking place in stages between September 2025 and July 2027:
- September 2025 - Industry systems go live with MHHS
- October 2025 - Migration starts across the energy industry
- August 2026 to May 2027 - Changes will go live for Drax Energy Solutions customers
- July 2027 - Ofgem’s target for MHHS completion
How will MHHS impact UK businesses?
If you already have a half-hourly (HH) meter, there’ll be no change to your current billing arrangements - everything will continue as normal.
If you have a non-half-hourly (NHH) meter, we’ll estimate your usage in line with new, MHHS-related industry processes.
If you’d prefer to upgrade to a HH meter, our metering team can arrange it. Simply get in touch at metering.enquiries@drax.com.
What are the key benefits for your business?
- More accurate, transparent billing
- Better insights into energy usage, allowing you to make more informed choices
- Access, potentially, to cost effective energy tariffs
- Support for the UK’s net zero goals
- Possible participation in demand-side flexibility services
When is Drax expected to migrate customers?
The current expected migration window is September 2026 to May 2027.
Will customers receive advance notice?
Where possible, Drax aims to contact customers in the month before their accounts migrate.
Will MWHHS migration be treated as a material contract change for any customers?
No. MHHS migration will not be treated as a material contract change because existing customer contracts are not being changed.
Will there be a cutover bill?
A final bill will be issued under the previous arrangements, after which the new billing approach will begin. Drax will try to avoid split bills where possible.
What happens if a conventional or non-smart meter is not upgraded?
The supply will still be settled on a half-hourly basis, but estimated usage may be derived from a generic profile or load-shaping service rather than actual consumption. This can give a less accurate view of usage and may affect cost.
Is MHHS mandatory for all business customers?
MHHS will become the standard for all metered electricity supply points, regardless of the size of the business or the level of consumption.
What should customers do if meters are outdated, faulty or not communicating?
Drax advises arranging a meter upgrade because estimated readings may be inaccurate. Contact metering.enquiries@drax.com. All metered and unmetered supply points remain eligible for MHHS migration.
Will bills always use actual half-hourly data?
Actual half-hourly data will be used where available. If it is unavailable, Elexon’s load-shaping service may be used to calculate estimated usage.
Where can you get further advice?
You can contact us using the details on your bill, or by emailing our metering team: metering.enquiries@drax.com.
You can also refer to Ofgem’s official MHHS resources.
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