Mandatory Half Hourly Settlement: What UK Businesses Need to KnowMHHS rollout from 2025: how metered half-hourly billing affects Profile Class 5-8 sites

Ofgem to assess case for mandatory half hourly settlement for smaller consumers

Launching its significant code review (SCR) on electricity settlement reform, Ofgem has said it will assess the case for a mandatory half hourly electricity settlement (HHS) process for domestic and smaller non-domestic customers.

Through use of smart and advanced meters, customers’ half-hourly consumption can be recorded and remotely read. Previously, the settlement process was based on half hourly estimates.

HHS means that customers are settled based on their usage in each half hour, as recorded, improving the accuracy and timeliness of the settlement process.

Ofgem regarded such a move as key in enabling innovation in smart tariffs and a necessary step in achieving potential benefits from demand-side response.

What Is Mandatory Half Hourly Settlement?

Mandatory half hourly settlement (MHHS) requires that a business’s electricity billing is based on actual consumption recorded in every 30-minute interval, rather than on estimates. For years, smaller non-domestic consumers on Profile Classes 5 to 8 were settled on profile estimates. MHHS replaces that with metered data.

The practical result is more accurate bills, reduced reconciliation disputes, and a billing structure that reflects when energy is actually used rather than an averaged assumption.

Which Businesses Are Affected?

MHHS applies to non-domestic customers on Profile Classes 5 to 8 — sites with a maximum demand below 100kW that are not already on half-hourly settlement. If your site has an advanced or smart electricity meter capable of recording and transmitting half-hourly data, you are or will be within scope. The rollout began in 2025, with suppliers migrating customers in phases under the programme managed by Elexon.

What Does This Mean for Your Business?

Under MHHS, your electricity costs reflect your actual half-hourly usage profile. If your consumption is concentrated in high-demand periods, your effective settlement cost may increase. If you have flexibility to shift load to off-peak periods, MHHS creates a direct financial incentive to do so.

It also makes demand side response programmes, time-of-use tariffs, and on-site assets such as battery storage directly relevant to your settlement position in a way they were not under profile-based billing.

What Should You Do?

Confirm your metering position with your supplier. Check whether your existing meter is advanced-metering-capable and whether your data collection arrangements are in place. If you want to understand how MHHS affects your procurement strategy, get in touch with Catalyst.

Talk to Catalyst about MHHS and your energy procurement →

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