How do half-hourly meters work?

If you run a large business that uses lots of energy, you should have a half-hourly meter by law. But what exactly are half-hourly meters, how do they work, and can they help you save on your business electricity bills?

Sofia Hutson

Utilities expert

minute read

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Posted 14 JUNE 2021

What is a half-hourly meter?

A half-hourly meter, also known as a HH or 00, is an electricity meter for businesses that sends automatic readings to your energy supplier every 30 minutes.

Both the older-style Advanced Meter Reading (AMR) devices and the newer smart meters can take half-hourly readings. For businesses that consume 100 kilowatts (kW) or more during any half-hour period, a HH meter is a legal requirement.

How do half-hourly meters work?

HH meters take a meter reading every half hour and automatically send the information to your supplier via a mobile signal or fixed phone line.

HH readings are fully automated and work remotely, so there’s no need for you to take any manual readings. It gives your supplier accurate and up-to-date details of your business energy usage. It means that your bills will be accurate rather than estimated.

Who are half-hourly meters for?

HH meters are compulsory for all businesses that use 100kW or more in any half-hour period during the day. They’re mainly used by larger, energy-intensive businesses like factories, warehouses or large office complexes.

Smaller businesses which have a maximum half-hourly demand of 70kW or more can also opt to have a HH meter installed.

Does my business need a half-hourly meter?

If your business has a peak demand of 100kW or more every half hour then you’ll have no option but to have a HH meter installed. Under the Government strategy to reduce energy usage, all businesses must be offered the chance to have a smart meter installed by 2024.

If your business doesn’t have a smart meter yet, you should already be on an Advanced Meter Reading (AMR) device. This remote reading device also automatically sends readings to your supplier every half hour.

Although HH meters are mandatory for larger, energy-intensive companies, smaller businesses could also benefit from switching to a half-hourly tariff. Accurate readings mean you only pay for exactly what you use. It’s also a good way of monitoring your energy usage so you can take steps to increase your energy efficiency. Reducing your carbon footprint could also help cut the cost of your energy bills.

What is a P272 mandatory meter change?

P272 is an Ofgem rule that’s been in force since April 2017. Under the regulation, energy suppliers are responsible for changing Maximum Demand Meters (non-half-hourly) to half-hourly meters. The P272 regulation applies to businesses with 05-08 profile meters. This process change is known as ‘settlement’.

Before P272 was brought in, both domestic and non-domestic consumers were put into profile classes ranging from 01-08, based on how and when they consumed energy. These profiles were used for estimating billing. Since the change in regulations, business meters originally in profile classes 05-08 have been moved to HH meters (also referred to profile class 00 by the energy industry).

P272 was introduced to make the energy market more efficient and create more accurate billing for business consumers. Half-hourly readings mean that energy suppliers can accurately match the amount of energy they buy in, with the amount of energy a business customer actually uses.

How is half-hourly billing different to normal pricing?

Traditional electricity meters necessitate that you have to take manual readings and you could receive estimated bills. Half-hourly billing uses accurate, up-to-date readings of your energy usage. You’ll only be billed for the energy you use.

How can I tell if my meter is half-hourly?

If your meter is half-hourly, you’ll see ‘00’ next to the large ‘S’ on your electricity bill.

What are the benefits of half-hourly meters?

Accurate readings mean accurate bills
No more estimated pricing
Only pay for the energy you use
Helps you keep track of your energy usage
Could help your business be more energy efficient, which could help you save money on your energy bills
Could help your business reduce its carbon footprint
More accurate readings could make it easier to find a better energy deal at renewal

Frequently asked questions

What is a DNO?

DNO stands for Distribution Network Operator. Your local DNO manages and maintains the electricity network for your area. They’re in charge of the cables and wires that deliver electricity from the National Grid to your business. They’re not the same as your electricity supplier.

If your business has a half-hourly meter, you must have an agreement with your local DNO about the maximum amount of power your premises can take from the National Grid. This is so the local DNO can ensure their system has enough power to supply your needs. In turn, you’ll need to pay a charge based on your agreed maximum power load. This is called a Maximum Import Capacity (MIC), which is also known as Available Supply Capacity (ASC) or Authorised Supply Capacity.

What is an MOP?

MOP stands for Meter Operator. A MOP is the company responsible for fitting your electricity meter and for its upkeep. If you have a half-hourly meter, you’re legally obliged to get an MOP. Prices and services can vary, and contracts can be as long as five years, so it’s a good idea to shop around and compare quotes from a few MOPs before signing up.

Why do I need an MOP agreement?

You’re legally required to have a contract with your MOP if you have a half-hourly meter. The agreement will cover the supply and maintenance of your HH meter, as well as the data collection of your half-hourly readings.

What is a capacity charge?

The capacity charge, also called an availability charge, is what you’ll be charged by your local DNO. It’s charged monthly per unit (kilo-volt-amper - kVA) and covers maintenance of the electricity network.

What is a kVA charge?

This is another name for a capacity or availability charge. This covers the available power capacity provided to your business and is based on your Maximum Import Capacity (MIC). The kVA charge is paid to the DNO indirectly via your energy supplier on a monthly basis. You can find your MIC and kVA charge on your energy bill or by calling your local DNO.

Where can I compare business electricity deals?

Right here at Compare the Market. Together with our trusted industry partners Bionic, we’ll help you find an energy tariff to suit your business needs.

Compare business energy suppliers today and see if you can save.