What is a half hourly meter? A guide for UK business sites

A half hourly meter records how much electricity a site uses in every 30-minute period, 48 readings a day, and sends those readings to the people who settle and bill the supply. For a business that is the single most useful piece of energy data it owns, because a half-hourly meter shows the shape of demand rather than its total, and the shape is what sets the biggest charges on a commercial bill. It is also the only honest basis for deciding whether a battery is worth buying. This guide explains what the meter is, how to tell whether your site has one, what the industry rules changed and where the data goes next.

What a half hourly meter does

A conventional meter records a running total. A half hourly meter records consumption in 30-minute settlement periods, so for a given day it can show that a factory drew 420 kW between 16:00 and 16:30, 180 kW overnight and 60 kW on a Sunday afternoon. In Great Britain those readings are collected remotely, passed to the supplier and used in electricity settlement, the industry process that works out which supplier is responsible for how much energy in each half hour.

On larger supplies the meter does not sit on the live conductors. It takes a scaled signal through current transformers, which is why you may see “CT metering” on a quote or a meter operator’s paperwork. The meter is usually owned and maintained by a meter operator (MOP) appointed under your supply contract, with a data collector (DC) retrieving the readings. Those three parties, supplier, MOP and DC, are the ones to ask when you want the data.

How to tell whether your business is half hourly metered

Three signs, from the easiest to check:

1. The MPAN top line. Every supply has a 21-digit Meter Point Administration Number. Its top line starts with a two-digit profile class. A supply settled on its own half-hourly readings carries profile class 00, the class Elexon reserves for half-hourly supplies in its MPAN guidance. Our guide to finding your network operator from the MPAN shows where the other digits point.
2. The bill structure. A half-hourly bill normally carries an agreed capacity or availability charge in kVA, time-banded unit rates or a separate line for distribution charges, and often a reactive power charge. A single blended unit rate with a standing charge is the shape of a non-half-hourly supply.
3. Who you deal with. If a meter operator or data collector is named in your contract, or your supplier has ever sent you a half-hourly data file, the supply is half-hourly metered.

If none of those applies and the site is small, it is probably settled on an industry load profile, which is what the profile classes describe.

Profile classes, in plain terms

Elexon, which runs electricity settlement under the Balancing and Settlement Code, publishes the profile classes used for supplies that are not settled half-hourly:

A profiled supply is billed on an estimate of its shape, drawn from the class average. A half-hourly supply is billed on its own shape. For a site with sharp weekday peaks the difference is not academic: on a profile the peak is averaged away; on half-hourly data it is paid for, and it can be managed.

What P272 changed

Before 2017 a mid-sized business could have an advanced meter and still be settled on a profile. Industry modification P272 made half-hourly settlement mandatory for all metering systems in profile classes 5 to 8 where capable metering had been installed, and it was implemented on 1 April 2017 after the regulator extended the original April 2016 date by a year. Separately, every meter in classes 5 to 8 has had to be an advanced meter capable of remote reading since 6 April 2014. The practical result is that most non-domestic sites with a maximum-demand supply are now settled on their own readings, and have been for the best part of a decade.

Market-wide half hourly settlement: what comes next

The remaining profiled supplies are being moved to half-hourly settlement through the Market-wide Half-Hourly Settlement (MHHS) programme, which Elexon runs with Ofgem as sponsor. The programme’s milestone plan sets 18-month migration periods for advanced-metered and unmetered supplies and then for smart and non-smart metered supplies, with full migration completion as a later milestone; its published progress page records milestone M14 as delivered on 28 October 2026. For a business the effect is that half-hourly data stops being a feature of large supplies and becomes the basis of settlement for all of them, which is why suppliers are increasingly pricing smaller business contracts on the shape of demand too.

What a half hourly meter changes on the bill

Once a supply is settled half-hourly, three charges follow the shape of demand rather than its total:

• Distribution unit rates by time band. The network operator charges a different rate for units in its red, amber and green bands. In the East Midlands in 2026/27 the low-voltage red rate, 16:00 to 19:00 on weekdays, is 7.777p/kWh against 0.054p/kWh in the green band, from National Grid Electricity Distribution’s published schedule. Our DUoS charges guide explains the bands and where they sit on the bill.
• Capacity. The supply has an agreed maximum import capacity in kVA, charged per day whether or not it is used, with an exceeded-capacity charge for any month the site goes above it.
• Supplier time-of-use pricing. Many half-hourly contracts carry a peak and off-peak unit rate or pass the network bands through directly, so the same kilowatt-hour costs more at 17:00 than at 03:00.

A profiled supply pays for all of this too, but through averages. A half-hourly supply pays for its own peaks, which means the peaks can be moved.

Where the data comes from, and what to do with it

Ask your supplier, data collector or meter operator for twelve months of half-hourly consumption against your MPAN; the usual format is a CSV with 48 values a day. Our guide to half hourly data explains the four numbers worth pulling out of the file: the size and timing of the peak, how often it lands in the red band, the overnight base load and the gap between the two.

Those numbers are the inputs to the peak shaving calculator, which applies the published red, amber and green rates and the capacity charge for your network area to the peak a battery could hold off the grid. It does arithmetic on your figures and estimates nothing. Our guide to commercial battery storage sets out the rules and the six checks that follow. If the result is worth pursuing, send us the details and we reply by email with what the published figures say for a site like yours; there is no installer partner behind this site and nothing is passed on.

The honest limits of the meter

A half hourly meter tells you what the site did, not what it will do. A new shift pattern, an EV fleet or a process change moves the peaks, and a year of data from before the change is only a starting point. It also records import, not what happens inside the site: it cannot say which machine set the peak, only when the peak occurred. And it is silent on the fixed part of the bill: since the Targeted Charging Review the residual network charge is a banded daily amount that no amount of load shifting reduces, which our targeted charging review guide explains. Use the meter for what it is good at: showing the shape, and putting a published price on it.

Sources

• Elexon, P272: Mandatory Half Hourly Settlement for Profile Classes 5-8: implemented 1 April 2017; advanced meters required in classes 5-8 since 6 April 2014.
• Elexon, Profiling: the profile classes 1 to 8.
• Elexon, MSIDs and MPANs guidance note: profile class 00 for half-hourly supplies.
• MHHS Programme, programme homepage and milestones: Elexon as programme SRO, Ofgem as sponsor, migration periods and milestone M14 (28 October 2026).
• National Grid Electricity Distribution, Schedule of charges and other tables 2026/27, East Midlands: red, amber and green unit rates and the capacity charge.

Independent guidance published by SEO Dons Ltd. We are not an installer, an energy supplier or a meter operator, and there is no installer partner behind this site.