The GB electricity market is going through a programme of change that was originally going to finish in 2026. When will meter migration really be completed?
The Market-wide Half-Hourly Settlement scheme (MHHS) represents a big change to how energy suppliers measure consumption and charge their customers. It means completely phasing out manual meter readings for all electricity customers on the UK mainland. As we explained back in May 2024, the goal is for all measuring and billing to be on a half-hourly basis.
A full implementation of MHHS will mean that every home and business in England, Scotland and Wales has a smart meter capable of half-hourly data capture.
When will my meter be upgraded?
The MHHS project has required a large-scale programme of meter upgrades. You may have read that this was scheduled to start in March 2025. The start was delayed because it took longer than planned for suppliers to finish testing their systems for compliance with the new national system.
Meter migration couldn’t start until suppliers were sure that their systems worked with the new MHHS set-up. When the testing phase overran, the organisers asked for more time. Ofgem granted their request in late 2024, agreeing an extra 6.5 months. As we reported, that pushed the start of meter migration back to October 2025.
Migration is now under way and is scheduled to end in October 2026. So if your business doesn’t already have smart metering, you can expect your upgrade in the coming months.
No going back to “dumb mode”
It’s currently possible to have a smart meter but not run it in smart mode. Customers can opt out of half-hourly readings and get daily readings instead. (For older smart meters where daily is the default, you can opt out of daily readings and choose monthly.) According to Ofgem, a small minority of smart meters are operating in this way. Others may be in “dumb mode” because of technical issues like a loss of connection.
The migration project aims to get all smart meters operating in smart mode. One of the milestones of the MHHS project is a cutoff date after which it won’t be possible to opt out of smart mode any more. This date is also the deadline for suppliers to qualify to be part of the new system. If they don’t meet the requirements, Ofgem will ban them from taking on any new customers.
This qualification date for suppliers and “point of no return” for customers has also been moved from the original date to allow more time. It would have been mid-March 2026 and it’s now late October 2026.
Quicker billing and less guesswork
Another key part of the metering reforms is a speeding up of the settlement timetable. Without smart metering, suppliers estimate your electricity use based on information like average usage and your pattern of consumption in the past. Then they adjust it based on actual meter readings and see how it matches the amount of electricity they’ve bought on the wholesale market. That’s the settlement process, and the current rules allow up to 14 months for it. The MHHS project aims to shorten this to four months.
Since April 2017 there has already been a rule that UK businesses over a certain size get billed on their usage in much closer to real time. If a business has metering capable of half-hourly settlement, this is what suppliers have to give you. In the industry it’s known as rule P272. Soon half-hourly settlement will be extended to all customers.
MHHS: key dates
October 2025 | Start of meter migration |
October 2026 | Completion of meter migration |
Late October 2026 | “Point of no return” where smart meters can’t go back to monthly or daily readings |
Early July 2027 | Shift to new settlement timetable (quicker billing) |
Where are we now?
The MHHS project is proceeding in line with the revised version of the timetable as agreed in late 2024. We don’t predict any further significant slippage to the timetable. As you’ll see from the list of dates above, we’re in the meter migration stage.
There is plenty of other work going on at the same time that won’t be apparent to us as consumers but is vital to the success of the project.
Sustainable Energy First helps businesses handle the physical upgrade to smart metering. We can also advise on getting the most out of your energy data, whether that’s for compliance reasons, net zero goals or just trying to make sense of it all. For a no-obligation chat, please get in touch.
