What is Market-wide Half-Hourly Settlement?

No, you don’t need to have a meter installed. Your supply will continue in the same way.

The primary supply number (MPAN) that will be retained will appear on your invoice.

No, all your unmetered supply equipment will remain connected. If you want to make changes to your equipment or its energisation status, please contact your UMSO.

This role is defined by the electricity industry to manage unmetered supplies, making sure the arrangements for unmetered supplies are correctly applied. Each electricity network operator appoints a UMSO who ensures the following:

• Establishing a connection agreement.
• Maintaining an accurate inventory of unmetered equipment.
• Creating and updating an Unmetered Supplies (UMS) Certificate.

You can find a list of UMSOs, their contact details and which MPANs they cover here.

New unmetered supply connections are now only available as half-hourly.

A phased plan and early migration for unmetered supplies will allow plenty of time ahead of the MHHS transition for suppliers and Unmetered Supply Operators (UMSOs) to resolve any issues that may arise.

If you’re on our variable business rates, you can switch to another supplier at any time (if any amount due is unpaid we may object to the switch). However, all suppliers will be moving unmetered supplies to half-hourly settlement. Another supplier may require your supply to be updated before they register it, or they may update it themselves after registration.

If you have an existing contract, you can’t switch to another supplier until the contract end date. Once your contract expires, you’ll be free to switch to another supplier.

You can check your terms and conditions here.

If your existing contract ends before the change of measurement class is completed, you can get in touch with us to discuss your options. Otherwise, you’ll be temporarily placed on our VBR NHH Street lighting / Unmetered supplies tariff; then after the change, you’ll move to our VBR HH unrestricted LV and LVS tariff. You can find our VBR here.

This is an industry-wide regulatory change that all unmetered supplies must undergo, mandated by Ofgem under P434. All energy suppliers are updating unmetered supplies to comply with this change by October 2025.

The impact of these changes will depend on your tariff and whether you have multiple supply numbers (MPANs) within your unmetered equipment inventory (as agreed with your Unmetered Supply Operator (UMSO).

You’ll move to our VBR HH unrestricted LV and LVS tariff. You can find more information about our current VBR on our out of contract rates webpage

Your existing rates will not be affected by the change of measurement class. We’ll incur higher costs when we move your supply to half-hourly settlement, but we won’t pass these on to you.

When your contract ends, the renewal offer will be based on half-hourly settlement.

Your invoice will include additional charges to cover the cost of your data collector and meter administrator. We’re appointing these agency services under the regulatory obligation to prepare for MHHS.

When your contract ends, the renewal offer will be based on half-hourly settlement.

Your MPAN / Supply Number is usually on your invoice and may appear like the image below (see the Distributor ID).

With the move to MHHS, Standard Settlement Configuration will replace Meter Time Switch Code, and Distribution Use of System (DUoS) Tariff ID will replace Line Loss Factor Class.

These changes won't interrupt your supply or switch you to another supplier.

No, your billing cycle will remain the same.

No, your invoice structure number will remain the same.

The roles of MOPs and DCs are evolving. MOPs will transition to Metering Services, and DCs will transition to Data Services. Existing MOPs and DCs will need to qualify for accreditation in these new roles. The specific details will depend on the agent you have a contract with and their post-MHHS roles.

Please let us know if you have an independent agreement with any metering service providers. If you haven't chosen any agents, we’ll appoint them on your behalf.

The impact of these changes will depend on your price plan and any new or additional costs we incur during this transition.

Due to the scale of this change and the new service processes and systems, we’re currently unable to predict these costs. We’re working diligently to finalise these. If we do need to add any additional costs, we’ll always inform you in writing beforehand.

Future costs across the energy industry will be lower with MHHS in place, than without this regulatory change. So, while costs may increase in the short term, they won’t rise as sharply, saving you money in the longer term. Ofgem predicts that GB consumers should see net benefits of £1.6bn-£4.5bn by 2045.

If a supply is unmetered, we’ll also need to appoint data and meter administration agents, so your bills will include additional fees.

We’ll use your half-hourly data primarily for forecasting and settlement purposes, to help us accurately predict energy demand and manage supply more efficiently. Additionally, we’ll use your half-hourly data to provide more accurate billing and to improve our product offering.

Our smart data guide and our privacy policy set out the standards you can expect from us when we request or hold your business’s information, including your half-hourly meter readings.