MHHS: the quiet electricity change that's already reaching your business
You might have spotted a new code on your last electricity bill, or heard a supplier mention "half-hourly settlement" in passing. It's part of the biggest shake-up to the electricity market in years, and it's already happening. Here's what it actually is, whether it costs you anything, and where there's genuinely money to be saved.
The short version
Every electricity meter in Great Britain is being moved onto a new way of measuring usage. Instead of the industry estimating how much power you used and when, it now works from what your meter actually recorded, in half-hour blocks. That's the whole reform. It's called Market-wide Half-Hourly Settlement — MHHS for short — it's mandated by the regulator, Ofgem, and the day-to-day delivery sits with Elexon, the body that already runs electricity settlement.
It is, we'll be honest, a fairly dry subject. But it quietly changes a few things that matter to a business, and there's one myth doing the rounds that could cost you real money if you fall for it. We'll come to that at the end.
First, what "settlement" even is
Settlement is the wholesale accounting that goes on behind your bill. Every day, suppliers have to square up how much electricity they bought on the market against how much their customers actually used. You never see it, but you pay for its inaccuracy: when the system runs on estimates, the cost of getting it wrong gets smeared across everyone's rates.
For years, that's exactly how most non-domestic sites worked. Unless you were a large business on a half-hourly meter, nobody really knew when you used your electricity. Your supplier bought power against a broad regional profile — a rough shape of what a "typical" site like yours might do — and trued it up months later. MHHS ends the guessing. Your usage gets settled in 30-minute slices, much closer to what you genuinely pulled from the grid.
Why the industry is bothering
Three reasons, in the order that matters to you. Accurate billing comes first: when the system knows what you used and when, your bills track reality instead of an estimate, and there's less slack cost baked into everyone's rates.
Then there's the interesting one — time-of-use tariffs. Once a supplier can see when you use power, it can price it differently: cheaper overnight or midday when wind and solar are plentiful, dearer at the teatime peak. For any business that can move some of its load around, that's a real lever on cost. And underneath it all is net zero. If enough businesses shift demand off the peaks, the grid leans less on the expensive, carbon-heavy gas plants that only fire up when things get tight. Ofgem reckons the reform is worth somewhere between £1.6bn and £4.5bn to consumers and businesses over the next couple of decades.
For most businesses, MHHS won't move a penny on the bill by itself. What it changes is what you can do about it.
- Accurate billing
- Time-of-use tariffs
- Faster settlement
What's actually changing behind the scenes
You don't need any of this to stick — but it explains the new acronyms creeping onto your paperwork, so here's the quick tour. There's a new national system, the Data Integration Platform (DIP), that shuffles meter data between suppliers and network operators in near real time. The old "half-hourly / non-half-hourly" labels are being retired in favour of "Advanced" and "Smart" meters, which is why bills issued since late 2025 carry a new settlement configuration code where the old meter timeswitch code used to sit.
If you haven't got a smart meter, a central Load Shaping Service estimates your half-hourly pattern from a large sample of similar sites plus your annual usage — better than the old crude profiles, but still an estimate. And the whole process speeds up sharply: the final reconciliation that used to drag on for 14 months now wraps up in four. Same electricity, the same meter on the wall in most cases — just a far sharper system behind it.
So do you actually need to do anything?
For most businesses, no. The migration is your supplier's job, it happens automatically, and there's no deadline you have to hit. But the honest answer depends on where you're starting from, so here's what we tell clients when they ask.
If you already have a smart meter , you're sorted — you're moving across in the background and your real data is doing the work. If you don't , you'll still be settled half-hourly, just on a modelled estimate rather than your own readings. That's fine for billing, but it keeps you locked out of the useful stuff: seeing your real usage, and qualifying for the better flexible tariffs. Upgrading is the one thing genuinely worth doing, and it costs nothing to ask your supplier. If you're a larger site already on a half-hourly meter , almost nothing changes beyond the wording on your paperwork. And if you're coming up for renewal in the next few months — that's the moment this matters most, and it's where a broker earns their keep.
Where the opportunity actually is
The savings don't come from MHHS itself. They come from what you do with the visibility it gives you. Take any business that can shift load — a bakery running ovens, a workshop charging a fleet of vans overnight, a unit with serious refrigeration. If some of that can move to cheaper hours, a time-of-use tariff turns that flexibility into a lower bill without changing a thing about what you produce.
Even businesses that can't move much still benefit from finally seeing their half-hourly data. It's remarkable how often it turns up something daft — heating or compressors running full tilt through the night, a base load that never drops at the weekend when the place is empty. That's the quiet promise of MHHS: not a magic discount, but the information to stop paying for waste, and to get rewarded for flexibility you already have.
The one myth worth ignoring
Here's the thing we get asked about most, and the bit some guides get flatly wrong. You'll read that MHHS is about to load new meter operator, data and capacity charges onto every business bill. It isn't. That warning is lifted from an older change called P272 , which affected sites being physically upgraded to half-hourly metering. Elexon have been blunt about it: MHHS is not P272. Settling your existing meter half-hourly does not convert it, and does not bolt those charges on.
✗ What you'll hear
"MHHS means new standing charges, meter and kVA fees on every business bill." Widely repeated, and wrong.
✓ What's true
Those costs come from upgrading to a half-hourly metered supply — not from MHHS settling the meter you already have.
There is one genuine cost worth watching, but only if you do move to a half-hourly supply: some sites end up paying for capacity — measured in kVA — they never actually use, occasionally a few thousand pounds a year. It's completely avoidable, but only if someone checks your agreed capacity against what you really draw. We do that as a matter of course.
MHHS is plumbing, not a price rise. But your renewal is the moment the right meter and tariff can genuinely lower your costs — and the moment the wrong ones quietly won't.
If you'd like it checked against your own situation, we'll look at your meter type, your usage shape, whether a time-of-use tariff suits you, and whether you're carrying capacity you don't need. No obligation, and no jargon.
General information to help UK businesses understand MHHS, not financial or contractual advice. Programme dates follow Elexon's published plan and may change.
