Updated 25 Sep 2026 · Current MHHS position
MHHS Explained for Business: What Has Changed, What Comes Next and What Should You Do?
Market-wide Half-Hourly Settlement is already live and millions of electricity supplies have moved into the new arrangements. It changes how the industry settles your electricity consumption, but it does not automatically mean a new meter, a new tariff or a higher bill. Here is the September 2026 position in plain English.
Suppliers began moving MPANs into the new MHHS arrangements in October 2025.
MHHS changes settlement. A meter replacement is a separate issue.
Whether you save depends on your load shape, tariff and how flexible your demand is.
The new fixed-term contract requirement from September 2027 is related, but it is not MHHS.
MHHS is a change to the electricity settlement system, not an instruction telling every business to replace its meter or move onto a time-of-use tariff.
Settlement is the behind-the-scenes process that matches the electricity suppliers buy against the electricity their customers actually use. Historically, many smaller sites were settled using broad consumption profiles rather than a site-specific half-hourly pattern.
Under MHHS, every Great Britain electricity MPAN moves into the new settlement arrangements. Where actual half-hourly data is available from a suitable smart or advanced meter, that data can be used. Where it is not available, the market can use load-shaping methods to create half-hourly settlement values from the information it does have.
That distinction matters: half-hourly settlement does not necessarily mean your physical meter is recording and sending actual data every 30 minutes.
Central MHHS systems went live in September 2025 and supplier migration started on 22 October 2025. On 22 July 2026, the MHHS Programme announced that 50% of all industry MPANs had migrated.
The next major programme gate is M14 on 28 October 2026. By that point suppliers must be qualified and service-active so they can accept MPANs under the new Target Operating Model. The Programme Steering Group confirmed in September that M14 remained on track.
Suppliers started moving smart, non-smart, advanced and unmetered MPANs into the new arrangements.
The programme confirmed that half of all industry MPANs had reached the MHHS arrangements.
Suppliers need the qualifications, systems and active services required to take on MPANs under MHHS.
All MPANs should have reached the programme's defined acceptable MHHS end states.
The settlement timetable is starting to shorten too
MHHS is not only about migrating MPANs. It also replaces the old settlement timetable with a faster one. On 15 September 2026, the programme approved the first transition step to reduce Final Reconciliation from 14 months to seven months. The programme then intends to move toward a four-month final reconciliation under the M16 arrangements in 2027, subject to the remaining readiness decisions.
The July version described the market as being roughly a third migrated. That is now out of date. This page has been refreshed to reflect the latest published programme position and the September settlement-timetable decision.
Under the old non-half-hourly arrangements, smaller sites were commonly represented by standard profiles that estimated the shape of consumption across the day. MHHS creates a market where settlement is carried out in half-hour periods across the board.
The exact data route depends on the metering arrangement. A suitable smart or advanced meter can provide actual interval data. A traditional or non-smart meter can still be migrated into MHHS, but the half-hourly settlement values may be calculated through load shaping rather than measured directly by the meter every 30 minutes.
This gives suppliers a much clearer picture of the site's real load shape.
The market can use load-shaped values based on register readings and wider consumption information.
Migration changes settlement arrangements. It is not the same as a physical new connection.
Settlement granularity and how often your supplier invoices you are two different things.
A physical meter exchange and migration into MHHS are separate things.
Suppliers may develop more load-shaped products, but your contract still determines how you are charged.
A flexible site may benefit from sharper pricing opportunities. A peak-heavy site can also become more expensive under a tariff that prices those peaks more directly.
Those charges depend on the actual metering, capacity and contract arrangements at the site. MHHS settlement itself is not a blanket new line item.
Better load-shape information can allow suppliers to price a site with greater precision instead of relying as heavily on broad assumptions about when that type of customer normally consumes electricity.
That creates potential for more time-sensitive tariffs and products. A business that can move meaningful demand away from expensive periods may have opportunities that were harder to price under the old arrangements.
Think of refrigeration, EV charging, heating, ovens, compressors, process loads or battery charging. If some of that demand can be moved without disrupting the operation, detailed interval data can make the value of that flexibility easier to see.
But MHHS does not make off-peak electricity automatically cheaper for every business. Any tariff still needs to be modelled against the site's actual operating profile.
MHHS changes how electricity consumption is settled across Great Britain.
The separate 2027 business smart-meter contract rules affect certain smaller and medium-sized non-domestic electricity and gas customers entering new fixed-term contracts from 1 September 2027.
Under those rules, a qualifying customer entering a new fixed-term contract will need to already have, or agree to have, suitable smart or advanced metering installed.
A business can therefore be migrated into MHHS before that date without the two policies being the same event.
It covers who is in scope, whether a business can refuse a smart meter, landlord and technical barriers, and what happens from September 2027.
Read: Business Smart Meter Rules 2027 →Do not assume “half-hourly settlement” tells you whether the physical meter is smart, advanced or traditional.
Interval data is most useful when somebody actually looks at it. Overnight base load, weekend consumption and avoidable peaks are often easier to spot visually.
A tariff designed around cheap off-peak periods is only attractive if your operation can genuinely use those periods.
If your site already has more complex half-hourly or capacity arrangements, make sure MOP, data and kVA costs are understood rather than assuming MHHS created them.
Meter type, load shape, supplier, contract structure and market timing should be looked at together.
What does MHHS stand for?
MHHS stands for Market-wide Half-Hourly Settlement. It is the reform moving Great Britain electricity MPANs into settlement arrangements based on half-hour periods.
Is MHHS already live?
Yes. Central systems went live in September 2025 and meter-point migration started in October 2025. The programme announced that 50% of industry MPANs had migrated by 22 July 2026.
When will MHHS migration finish?
The current M15 target is 7 May 2027. M16 then governs the move to the faster enduring settlement timetable, with transition steps being introduced through 2027.
Does my business need a new smart meter because of MHHS?
Not simply because of MHHS. A non-smart MPAN can still be moved into the new settlement arrangements using load-shaped values. Separate smart-meter contract rules begin for qualifying new fixed-term contracts from September 2027.
Will MHHS make my electricity cheaper?
Not automatically. MHHS can support more accurate load-shaped pricing and time-sensitive products, but the result depends on the tariff and when your business actually consumes electricity.
Will I be billed every half hour?
No. Half-hourly settlement describes how consumption is accounted for in the market. Your supplier can still invoice on its normal billing cycle.
Does MHHS mean new MOP or kVA charges?
No blanket new charge is created simply because an MPAN migrates into MHHS. Metering, data-service and capacity charges depend on the site's actual technical and contractual arrangements.
Use the data, rather than just having it.
We can review your contract end date, meter arrangement and consumption profile together, then compare the contract options that actually fit how the site uses electricity. MHHS does not guarantee a saving, but better data gives you a better basis for making the decision.
