Half-hourly meters explained for business: what they are and why they matter

If your electricity bill mentions half-hourly data, a half-hourly meter or an MPAN starting 05 to 08, you are in a slightly different corner of the market from a business on a basic meter. It is also a corner that is growing, because the whole electricity system is being moved onto half-hourly settlement.

This guide explains in plain English what that means, how to check what you are on, and why it affects how your usage is measured and billed. We are an introducer, not an adviser, so we explain what the sources say and leave the decisions with you.

What is settlement, and why half-hourly?

Ofgem’s description is a good starting point. Settlement is the process for charging suppliers for the difference between how much electricity they buy and how much their customers actually use. Traditionally, suppliers have estimated customers’ use based on the average customer’s pattern, and settlement then reconciles any discrepancies.

With smart meters that record consumption every half hour and transmit it, the industry can use real figures instead of estimates. Ofgem says this gives suppliers a much more accurate picture of consumption and demand, so they can match their purchases accordingly and bill customers more accurately, based more closely on the cost of generating and supplying the electricity they use.

How to tell if your business is half-hourly settled

Ofgem gives a simple check. Look at your Meter Point Administration Number (MPAN), also called the supply number, on your electricity bill. If the first two digits are 05, 06, 07 or 08, your supplier is taking half-hourly readings from your meter.

If you cannot find your MPAN, your supplier can tell you. Ofgem says suppliers must put your supply number on each bill or statement.

Who has had to be half-hourly, and since when?

Ofgem says that from 1 April 2017 all medium and large businesses must be settled on their half-hourly electricity use. In the industry this is known as code modification P272. The aim was for businesses to have detailed usage information they can use to shop around for a supplier offering value for their specific needs, and for suppliers to offer time-of-use tariffs that reward moving consumption away from peak periods.

From July 2017 Ofgem also made it easier for suppliers to settle small business and household customers half-hourly. Since then, the direction of travel has been towards everyone.

The market-wide switchover (2025 to 2027)

Elexon, the body Ofgem appointed to implement the reform, calls Market-wide Half-Hourly Settlement one of the biggest changes to the electricity retail market since competition began in the late 1990s. Its published timeline says:

• Central systems were ready for migrating meter points in September 2025.
• Suppliers began migrating customers’ meters to half-hourly settlement from 22 October 2025.
• Elexon expects to have accepted approximately 80% of meters into the new arrangements by October 2026.
• Implementation completes in May 2027.

Elexon says that once half-hourly settlement is fully implemented, the time to complete settlement reduces from 14 months to four. It also says granular consumption data can be used by suppliers to develop products that reward consumers for being more flexible in how they use electricity, and that consumer consent controls are being developed so people can manage who can see their data.

What does half-hourly data mean for your business?

Ofgem says half-hourly data means households and businesses know how much electricity they are using, and can choose to use more or less in response if they wish. That might suit them if they want to avoid times of day when electricity is expensive to generate, when generation relies on fossil fuels, when many others want electricity, or when networks are strained.

Possible benefits

• Visibility. You can see when you use electricity, not only how much in total. Ofgem says billing based on real use is more accurate.
• Time-of-use tariffs. Ofgem describes smart tariffs as price signals where lower prices reflect lower cost of generating and moving electricity at certain times. Prices are lower when there is lots of wind and solar, and higher when more expensive generation is in use.
• Support for flexibility. Ofgem says technology like energy storage can shift use or respond to price, for example a battery recharging when electricity is cheap.

Things to keep in mind

• Whether you benefit depends on when your business uses power and whether you can move any of it.
• Not every supplier offers every tariff type. Ask what is on offer for your meter type.
• Check how your contract treats network and other non-energy costs, which Ofgem says make up part of a business bill.

Questions to ask about your meter

1. Is my site half-hourly settled? Check the first two digits of your MPAN.
2. What type of meter do I have? Traditional, AMR or smart.
3. Are my readings actual or estimated? Ofgem says to submit regular readings or get a smart meter so you pay only for what you use.
4. Do I have access to my half-hourly data? Ask your supplier what you can see.
5. Do the quotes I am given take my usage pattern into account? Ask for the tariff structure and compare against your own bill.

A short glossary

Usage data and your bill

Ofgem’s billing guide says suppliers should tell customers what type of meter they have, and may note whether a customer can upgrade. It says a usage graph on the bill can help customers relate their energy use to their readings and costs, and that suppliers have to reflect readings in bills. If you are on a half-hourly meter, ask your supplier what usage detail is available to you, such as a portal or reports, and how often it updates.

Elexon also says that, from October 2026, it will begin publishing aggregated data from meters that have moved to the new arrangements, as part of work to make data available to support innovation. That is aggregated data about the market, not data about your site.

Frequently asked questions

Not sure what your meter details mean for your quotes?

Send us your latest bill. We introduce you to our energy partner, who gathers quotes and options from 50+ suppliers. You compare them and make the call. Absolutely no cost to you. It’s a free service.

Send us your latest bill