Our guide to the Market-Wide Half-Hourly Settlement (MHHS)

1. Building a smarter, cleaner energy system

The Market-wide Half-Hourly Settlement (MHHS) programme is a major step toward a flexible, low-carbon electricity market. It’s helping the UK move closer to Net Zero, while making the system smarter for everyone.

2. Better matching of supply and demand

MHHS helps suppliers, like us, see how much energy is used, when it’s used, and how much they need to buy. This makes the system more accurate and efficient, reducing waste and relying less on fossil fuels.

3. Benefits for our customers

• Potentially lower bills thanks to more efficient electricity purchasing
• Better insights into your energy use
• Supports a more modern energy system, built on how we live our lives

Our electricity system was designed for a totally different world, a world before electric cars, home working, smart tech and solar panels. Life’s changed, and the way we use energy has too.

Today’s reality

• We charge cars at midnight, work at home more, and our family lives are less routine
• Renewable energy comes and goes depending on the weather
• The grid needs to react in real time, not once a month

But the current system still relies on monthly estimates. It can’t tell when energy is used — only how much. That means more guesswork, more waste and more pressure on the grid.

MHHS fixes that. It gives the whole system the real-time insight it needs to run cleaner and smarter.

MHHS is a nationwide upgrade led by Ofgem. Instead of settling energy using monthly readings, the system will use half-hourly readings from smart meters (with your permission).

Why does that matter? Because knowing when energy is used helps everyone make better choices, from suppliers buying electricity to customers trying to use more renewable energy.

With half-hourly settlement, your smart meter sends us a reading every 30 minutes.

This lets us:

• Buy the right amount of energy at the right time
• Use more renewable electricity
• Avoid wasteful over-buying
• Help keep the grid stable and reliable

Better data makes the whole system fairer and greener.

Every day, the energy system checks how much electricity suppliers bought vs. how much customers actually used. If they don’t match, there’s a charge. This is called settlement.

Half-hourly settlement makes this more accurate, which helps keep costs fair.

What “balancing” really means

Balancing is how the grid keeps things stable. Better data means better forecasting. Better forecasting means more room for renewables — and less need for fossil fuels.

In short…

The old energy system wasn’t built for modern life. MHHS helps create a cleaner, smarter, more flexible energy future, and you’re a key part of it.

Half-hourly settlement unlocks a bunch of future-friendly benefits:

• More accurate billing
• More renewable energy in the mix
• A more efficient, stable grid
• Potential for cheaper costs long-term
• Smarter tools and tariffs coming your way
• Clear insights to help manage energy at home

It’s the foundation for a modern energy system.

We’ll start moving customers to half-hourly settlement from Winter 2025.  If you really don't want your smart meter readings to move to half-hourly that's totally your choice. 

Your smart data stays safe

Your trust matters. We only use your smart meter data for settling energy unless you tell us otherwise. You’re in control, always.

Changing your preferences

Want to switch to daily or monthly readings instead? No problem. You can update your preferences at any time in your online energy account. Follow these instructions

1. Log in to MyAccount
2. Click ‘Smart meter preferences’ on your homescreen
3. Under ‘Market-wide Half-Hourly Data Preferences’, pick how often your meter sends readings
4. Click ‘Submit preferences’ to save

Don't have an online account? No problem. Use our form, and our team will make the change for you.