The Market-Wide Half-Hourly Settlement (MHHS) programme is a major overhaul of the electricity system in the UK energy sector with the first phase scheduled to begin in October 2025 and all migration due to be completed by May 2027.
Mandated by Ofgem and delivered by Elexon, the initiative will ensure that electricity consumption is recorded every 30 minutes for all eligible meters across England, Scotland, and Wales.
By using actual half-hourly data, MHHS will modernise the energy system, enabling smarter and more responsive energy management. It will also play a key role in supporting the UK’s Net Zero targets by encouraging more efficient energy use and supporting the integration of low-carbon technologies such as renewable generation. Additionally, the programme will improve market efficiency and accuracy by reducing settlement imbalances and enabling more competitive, flexible pricing for consumers.
Accurate Billing
MHHS provides a more precise picture of electricity usage by measuring consumption in half-hourly intervals, reducing the reliance on estimates.
Enhanced Energy Management
With access to granular consumption data, customers can better monitor and manage their energy usage, leading to increased energy efficiency and potential cost savings.
The introduction of Market-Wide Half-Hourly Settlement (MHHS) will impact both electricity consumers and suppliers. For domestic and commercial customers, energy usage will be settled based on actual half-hourly data rather than estimates. This means more accurate billing and a clearer picture of how electricity is being used.
To benefit from MHHS, consumers will need to have a smart meter installed, as these devices can record and transmit energy usage every 30 minutes, something traditional or manual meters can’t do.
On the supplier side, energy companies will need to upgrade their systems to handle half-hourly data for all customers. This will make the settlement process more precise and ensure customers are billed fairly based on their real usage.
The programme is scheduled to be implemented in phases, with the first beginning in October 2025 where all eligible meters will start recording and settling electricity usage every 30 minutes. Between October 2025 and May 2027, when all suppliers have migrated, there will be ongoing monitoring and optimisation of the process as the new system becomes fully embedded.
It is important to note that this timeframe is a target and could be delayed or impacted by the previous phases.
If your business already has a smart meter installed, there’s nothing you need to do as you’re already set to benefit from the MHHS changes.
If you don’t yet have a smart meter, we recommend booking an installation as soon as possible. Having one in place will give you access to accurate, real-time data, helping you take control of your electricity usage and manage your bills more effectively.
