A New Era of Transparency in Your Electricity Billing

What does Market-wide Half-Hourly Settlement (MHHS) mean for UK businesses, and how to prepare?

Most UK businesses have been overpaying or underpaying on electricity for years. Not because of bad contracts. Not because of dishonest suppliers. Because the system itself was built on guesswork.

The REC code, established in 2021, created a regulatory framework through extensive industry consultation to bring greater oversight and accountability to these systems in the energy market.

While most customers provide meter readings through various methods, the industry has long recognised that demand and supply imbalances directly affect generation planning and consumption forecasting. Your supplier did not know precisely how much power your business used on a given day. So, they estimated, using a broad profile built from other businesses like yours. Some months, the estimate ran high. Others ran low. Either way, the number on your invoice was never quite the truth.

That is changing. Market-wide Half-Hourly Settlement, known as MHHS, is the most major reform to UK electricity billing since the market was privatised in the 1990s. Driven by Ofgem and delivered by Elexon, it is rolling out across the entire industry right now. From this point forward, electricity consumption will be measured with your consent and settled every 30 minutes, based on what your meter actually records.

This article covers what is happening, why it matters to your bottom line, what will look different on your documents, and what Maxen Power is doing to support customers through the transition.

£4.5 Billion Projected consumer savings by 2045 (Ofgem)

30 Minutes New measurement interval replacing monthly estimates

Since 1998 The biggest energy reform in the UK

1. The Problem with How Energy Bills Have Always Worked?

The ‘profiling’ system and why it has always been flawed.

To understand why MHHS is such a major reform, you first need to understand what it is replacing.

Right now, UK businesses operate under what the industry calls non-half-hourly settlement. Their electricity meters do not send continuous usage data to their supplier. Readings are infrequent. The supplier does not actually know when you used power or how much, not in any granular, real-time sense.

So, to calculate your bill, your supplier relies on something called a profile. A profile is a pre-built usage pattern that approximates how a business like yours is likely to consume energy across the week, across the seasons, across the year. It is constructed from historical data gathered from similar businesses in similar sectors.

On paper, this seems reasonable. In practice, it creates a billing system built on estimations rather than reality.

“Your baker gets the same profile as every other baker. Your warehouse mirrors every other warehouse. Precise? Not remotely.”

Say you have taken on more staff, upgraded your equipment, or simply run leaner than most businesses in your sector. None of that shows up in a profile. You end up overbilled or underbilled, and either way, your invoice doesn’t reflect what actually happened.

And the consequences ripple outward. Suppliers must buy energy from the national grid on the basis of these same profiles. When the profiles are inaccurate, the entire market is working from bad data.

How did we end up here?

The profiling system dates back to the early years of electricity deregulation. When the market was liberalised in the 1990s, the technology to measure and transmit real-time data from millions of meters simply did not exist at scale. Profiles were the best option available at the time, a reasonable workaround given the limits of 1990s technology.

Fast forward to today, and smart meters and digital communications have made real-time data collection completely routine. The old workaround no longer makes sense. MHHS is the industry catching up with what’s been technically possible for years.

2. What MHHS Delivers?

The name tells you the essential mechanic. Under MHHS, electricity consumption is measured based on consumer consent (either daily, monthly or HH) but settled on a half-hourly basis, meaning every 30 minutes, the exact amount of energy your premises have consumed is recorded and reported.

That data is used to settle the demand and supply in the industry. This will lead to actualisation, efficiency and net-zero carbon emissions.

The result is a system where every unit of electricity in the market is accounted for with precision. For the first time, what you use, what your supplier buys, and what the grid supplies all align.

The role of smart and advanced meters

Smart meters and advanced metering infrastructure (Advanced meters) are the physical tools that make this possible. These devices are already installed across a growing proportion of UK commercial premises. They automatically record consumption at regular intervals and transmit that data digitally, no manual readings, no estimated values, no lag.

If your business already has a smart or Advanced meter, you are likely already equipped to participate in half-hourly settlement. In most cases, your supplier just needs to configure it to start transmitting half-hourly readings.

 

3. The Real Benefits

Accurate billing

The most immediate and tangible benefit for most businesses is billing accuracy. With half-hourly data feeding directly into settlement, the era of the estimated bill will be gradually minimised.

No more unexpected credits building up over the year because your estimates ran high. No more surprise reconciliation charges because they ran low. Your monthly statement will reflect what your business actually consumed, nothing more, nothing less.

Better data for smarter business decisions

Half-hourly consumption data will be useful for billing. Think of it as a proper energy fingerprint, you will be able to see exactly when your usage peaks, which parts of the operation are pushing costs up, and how things shift across the seasons.

Right now, most businesses are running blind when it comes to their energy use. MHHS gives you the granular picture you need to actually manage it.

Supporting the UK’s net zero ambitions

The benefits of MHHS extend beyond individual businesses. At a national level, it’s directly tied to the UK’s net-zero 2030 targets, which is exactly why this is a mandate by Ofgem.

Renewables such as wind, solar, and tidal do not generate power on a fixed schedule. Output depends on the weather. That means supply and demand are often out of step, and without better data, the grid has no reliable way to manage it.

MHHS helps solve this problem in two ways. Granular consumption data lets grid operators forecast demand far more accurately, cutting the need to generate excess power just in case. And when businesses can see and respond to live pricing, they can shift flexible loads to times when clean energy is running strong, which takes real pressure off the grid.

“MHHS is the mechanism that makes this coordination possible at scale.”

4. Industry Changes behind the Scenes

MHHS is reshaping the UK electricity market behind the scenes, though most businesses will only notice more accurate bills and minor document updates. The changes are purely administrative, and meters are being recategorised in industry systems, with no impact on your supply, contract, or supplier relationship. For businesses, it is straightforward:

“Nothing changes on your end; your supply carries on as normal.”

New arrangements for metering and data services

Under MHHS, the way metering data gets collected and passed through the system is being redesigned. Metering and data services are being split out by meter type, and the old roles are being replaced with updated versions built for an updated MHHS world.

Regulatory oversight

MHHS is a regulatory requirement set by Ofgem, with Elexon overseeing delivery as the Senior Responsible Owner. Elexon oversees how electricity trades and settles in the wholesale market. This reform is one of the biggest changes that code has seen since the market opened.

Every supplier, metering agent, data provider and stakeholder is required to comply. There is no option out this is a mandatory regulatory programme.

5. Do You Need to Take Action?

The short answer is, it depends on your meter

For most businesses, day-to-day operations carry on unchanged. Your electricity supply would not be affected during the transition. Existing contracts are not automatically changed. The underlying reform is largely a wholesale and infrastructure-level change.

However, whether your business is positioned to benefit from MHHS, not just comply with it, depends on the type of meter you currently have.

If you have a smart or advanced meter

Good news, your meter can already do what MHHS requires, and since communication with existing meters is expected to be smooth, the transition should be seamless. As MHHS rolls out fully, you will automatically receive the benefits of accurate settlement, with no additional action required beyond any configuration your supplier may carry out.

If you have an older or traditional meter

Your supply will not be interrupted, and “you will need to contact your supplier to upgrade/change your meter to avoid hassle”. MHHS does not mandate meter upgrades solely based on meter age. Without a meter that can send half-hourly readings, you will stay on profile-based estimates for the time being. That means continuing with the same approximate billing and missing out on the visibility that accurate settlement brings.

Upgrading to a smart meter is strongly recommended for any business that wants to take full advantage of MHHS. The process is straightforward, and the long-term benefits in billing accuracy and energy management significantly outweigh the short-term disruption of installation.

If you already have a half-hourly meter

If you already have a half-hourly meter, businesses like yours have been settled on a half-hourly basis for some time, typically larger commercial or industrial sites. Your meter communications are already established, so the transition should require minimal changes on your end. MHHS simply extends this accurate settlement to the much larger population of businesses that were previously non-half-hourly. You are already operating the way MHHS intends, and your existing setup should remain largely unchanged.

6. How Maxen Power Is Supporting Customers?

At Maxen Power Supply Limited, we believe that energy should not just power businesses; it should empower them. MHHS represents an opportunity for UK businesses to gain real control over one of their highest overhead costs, and we are committed to helping our customers make the most of it.

What we are doing

• Proactively contacting customers who may benefit from a meter upgrade and explaining their options clearly.
• Ensuring our systems are fully aligned with the MHHS programme.
• Making meter installations easy to book and as straightforward as possible to carry out.

We are also serious about our own sustainability commitments. Moving to paperless communications sits within the same thinking that drives MHHS, using better data and smarter systems to minimise waste and leave something worth having for the next generation.

The Bottom Line

For too long, commercial electricity billing has been a system built on approximation. Businesses have been paying for an average instead of a reality, UK consumers billions of pounds in unnecessary over-billing, inefficient grid management, and missed opportunities for smarter energy use.

MHHS minimises that gap. A mandatory, industry-wide reform that brings the entire UK electricity market into an era of data-driven accuracy. For businesses with the right metering in place, it could translate into real savings, and a meaningful better understanding of where their energy costs actually come from.

The transition is underway. The question is not whether it will affect your business; it will, but whether you are set up to take full
advantage of it.

If you have a smart or advanced meter, you are ready. If you do not, now is the time to act.