Information About MHHS
What is MHHS?
Market-wide Half Hourly Settlement (MHHS) Programme is a major reform to the electricity system in Great Britain to modernise processes for matching trading, demand and electricity use in Great Britain.
By using more frequent and granular consumption information, MHHS aims to provide a more accurate picture of when electricity is consumed in Great Britain. This in turn is expected to encourage more innovation in products and services, more flexible electricity use and in turn support our transition to a net zero future.
What does MHHS mean for my business?
Most changes will take place behind the scenes. The main changes include:
- Changes to the granularity of data we collect. Where possible, we will start collecting your half-hourly consumption data. Where a meter upgrade is needed for us to start collecting half-hourly data from you, we’ll be in touch to arrange it. Where we need your consent to collect half-hourly data from you, we’ll be in touch to request it.
- Changes to billing. Subject to any required consents, we may start billing you based on your half hourly consumption. You may have noticed that the format of your supply number has changed.
- Changes to industry charges. Longer term certain customers with CT metering may notice a change to the industry charges we pass through to them.
If there is a specific change that affects your business, we will be in touch to explain the changes and how they may affect you.
What do I need to get MHHS ready?
Some customers will require a meter upgrade to transition to MHHS. We ask for your co-operation in carrying out the upgrade, including when we contact you to arrange it.
If you are a microbusiness customer and agreed a contract with us before 4 April 2024, we will ask you for access to your half-hourly consumption data. By allowing us access, you will contribute to our transition to a net zero future.
When will the change happen?
Transition to MHHS begun in September 2025 and is expected to be completed by July 2027 across the whole industry. We intend to transition to MHHS between June and October 2026.