From September 2025, Ofgem began introducing Market-wide Half-Hourly Settlement (MHHS). This is a big change in how electricity is measured and billed across Great Britain.

We want you to understand what’s happening and how it affects you.

 

The changes explained

Our Commercial Manager, Ben Mason, explains the
changes and what it could mean for you.

What is MHHS?

MHHS means electricity bills will be based on real data, collected every 30 minutes, instead of estimates.

Will my contract change?
No. Your current contract should stay the same.

Do I need a new meter?
If you already have a smart or AMR meter, you’re ready. If not, you may be asked to upgrade.

When will my site move over?
Suppliers started migrating customers in October 2025. All sites should be complete by July 2027.

What happens to my supply number?
The top line of your MPAN may change, and some old meter codes will be replaced. The bottom line of your MPAN – your unique identifier – will remain the same.

Why is this happening?
To improve billing accuracy, create more flexible tariffs, and support net zero.

What if I have a UMS (Unmetered Supply)?
As part of the Market-wide Half-Hourly Settlement (MHHS) changes, your Unmetered Supplies (UMS) will be consolidated under a single MPAN. This means that if you currently have multiple UMS MPANs for different assets, these will be combined into one MPAN to simplify your account and settlement process. You don’t need to take any action. If you have Unmetered Supplies (UMS), any consolidation of MPANs or updates to settlement arrangements will be handled on your behalf, by your supplier.

Who can I speak to?
You don’t need to take any action right now, we are simply keeping you updated of industry changes. However, your Utility Aid Account Manager is here to help if you are concerned – you can email us at heretohelp@utility-aid.co.uk.