Support / Migrating large businesses to Half-Hourly settlement

Migrating large businesses to Half-Hourly settlement

Ofgem authorised regulations for the energy industry which affect how all suppliers buy, transport and charge for electricity. Known as P272, these changes require certain businesses to switch to Half-Hourly metering. So if you fall within certain consumption levels, we might need to install a new meter or change the way we bill you.

We’ve put together a set of frequently asked questions to guide you through the changes.

Important information for brokers. Please make sure you:

  • Inform your customers of the pending changes
  • Understand how your customers’ contract start date fits in the P272 timeline
  • Explain that invoices will be based on Half-Hourly consumption
  • Ensure your customers are aware of their Maximum Import Capacity (MIC) if they have Current Transformer (CT) metering. It is important to ensure Availability Charges are based on an accurate MIC, otherwise Excess Capacity Charges may be passed through from the Distribution Network Operator (DNO)

What has changed?

P272 is the name given to the requirement for electricity suppliers to settle and bill customers with meters in profile classes 5-8 using Half-Hourly Meter Reads (where the relevant meter has been installed). These meter reads are automatically sent to us using an advanced meter (AMR).

Will your Opus Energy supply agreements remain valid?

Yes, your Opus Energy supply agreement will remain valid irrespective of the change from being settled on Non-Half-Hourly or Half-Hourly Meter Readings.

Will my meter need to be replaced?

Most of our customers affected by this change already have an advanced meter (AMR) installed which is capable of recording Half-Hourly energy consumption. These customers will not need any change to their metering. If you do not have an AMR yet, we will contact you to arrange an installation.

If a meter exchange is required, the power to the supply may need to be switched off for up to 1 hour. We will be able to arrange the appointment for a time where there is minimal impact to your business, even outside of your opening hours.

There is no cost to you to install the new meter. However, if third party remedial work is required in preparation for the meter exchange, the cost of this may be applicable.

Can I appoint a preferred Half-Hourly Metered Agent?

Yes, if you have a preferred Half-Hourly Meter Agent, please inform us at the point of requesting your new contract.

Once the meter is settled using Half-Hourly Meter Readings, will the Profile Class change?

Yes, meters settled on Half-Hourly Meter Readings will transfer to Profile Class 00.

Will my prices change?

All customers that have a contract in place will see no change to their Unit Rates or Standing Charges as a result of using Half-Hourly Meter Readings.

If you have Current Transformer (CT) metering, you will see an Availability (or Capacity) charge appear on your invoice. This is shown in pence per kVA per day and is based on an agreed Maximum Import Capacity (the amount of energy made available to you) for your supply. The Distribution Network Operators distribution company may have already contacted you to explain how this has been calculated.

If the Maximum Demand (what you use) exceeds your agreed Maximum Import Capacity, you will have to pay an Excess Capacity Charge. If you are concerned about this, we would advise you contact an electrician for a maximum demand report. If the report shows a different figure to the one recorded for your supply, you can submit the new one to your distribution company.

Customers with CT metering may also be charged for Reactive Power. The distribution company may levy a charge if more than 5% of the total power consumed is Reactive Power. This is because more current has to be provided to the property to produce the same end power output.

Can I change my kVA value for Maximum Import Capacity?

If you would like to amend your MIC, please speak directly to the relevant Distribution Network Operator. For a full list of contacts, please refer to the National Grid website.

Will agent charges be included in existing prices or will they be charged separately?

These charges are included in the existing prices unless we have stated that they are excluded on the quotation sheet or pricing schedule.

How can I tell if my metering has a Current Transformer?

Your supplier will be able to inform whether your metering has a Current Transformer. If we are your supplier, please contact your Account Manager who will be able to provide you with further assistance.

Will my invoice look different?

Yes. Once your metering has moved into the new arrangements you will no longer see a monthly start and end read. This will not affect the amount of energy you consume. You will be able to see all of the Half-Hourly meter reads in your online account.

You may also see some additional lines on your invoice which relate to charges from the electricity distribution company, such as an Availability Charge, Excess Capacity Charge or Reactive Energy Charge. If you are affected by any of these additional charges, your electricity distribution company will be able to provide further details of the charges and explain what they are.

How can I obtain a copy of my Half-Hourly Meter Readings?

Please contact your Account Manager if you require a copy of your Half-Hourly Meter Readings.


The following table provides an explanation of the terms used throughout the FAQ section.

Term Description
Availability Charge (Capacity Charge) An Availability Charge is typically based on your “peak” electricity use during a specific period. The charge is levied by the Distribution Network Operator and passed onto you via your electricity supplier. Depending on your location, the Availability Charge may be set annually or monthly. The Availability Charge is charged as pence per day per kilovolt-amps (p/day/kVA). It is important that your kVA accurately reflects the amount of electricity you need at peak times otherwise you may incur an Excess Capacity Charge.
Current Transformer A Current Transformer is used to accurately measure the amount of electricity used on high voltage electricity supplies. Low voltage supplies do not need a Current Transformer to be read accurately. If you are unsure whether your metering has a current transformer, please contact your current electricity supplier.
Distribution Network Operator Distribution Network Operators (DNOs) own and operate the distribution network of towers and cables that bring electricity from the national transmission network to homes and businesses. They don’t sell electricity to consumers, but pass on their charges for running the network via your electricity supplier.
Excess Capacity Charge If you exceed the kVA figure set by your Distribution Network Operator they will charge an Excess Capacity Charge via your supplier. The price of this charge is currently the same as the Availability Charge but will be higher from 1st April 2018.
Half-Hourly Meter Agent Half-Hourly Meter Agents consist of a Meter Operator, Data Collector and a Data Aggregator. A Meter Operator is an organisation responsible for installing and maintaining electricity meters. There is full competition for Meter Operators in Britain, allowing the Meter Operator for a particular supply to be contracted with the electricity supplier at either the supplier's discretion or the customer's direction. The Data Collector receives your Half-Hourly Meter Readings from the meter before passing them onto the Data Aggregator. The Data Aggregator receives your Half-Hourly Meter Readings from the Data Collector and aggregates it before passing it onto a central body responsible for monitoring how much electricity each supplier is using.
Half-Hourly Meter Readings These are interval consumption readings that measure the amount of electricity used within each half hour period of the day. Each interval read is added together for an invoice period to determine the billable consumption instead of using a start and end reading.
Maximum Import Capacity (MIC) The capacity of your connection (where the meter is installed) is the total electrical loading for which your connection is designed. Capacity is measured in kilovolt-amps (kVA). The capacity level for customers is described as the Maximum Import Capacity (MIC). You must choose a MIC that meets your needs. If you are unsure what your MIC is or should be, we recommend that you discuss this with your electrical contractor/consultant.
Non-Half-Hourly Meter Reading The amount of consumption used by this type of a meter is determined by calculating the difference between two meter readings, referred to as a ‘start read’ and an ‘end read’ on the electricity invoice issued by your supplier.
Profile Class A Profile Class (ranging from 1 to 8) is used where the meter is not capable of recording Half-Hourly Meter Readings. Profile Classes provide the electricity supplier with an expectation as to how much electricity will be used throughout the day. Your Profile Class will give your electricity supplier an idea of your daily electricity usage pattern. This in turn is reflected in the Standing Charge and Unit Rate(s) that you will be charged. As a general rule, higher usage needs a higher profile.
Reactive Power Charge Reactive Power is an additional quantity of ‘unproductive power’ that some electrical equipment needs to work effectively. The Distribution Network Operator may levy a charge if more than 5% of the total power used is Reactive Power (most customers use less). This is because more current has to be provided to the meter to produce the same end power output.
Standing Charge This is a pence per day charge (p/day) and is levied by your electricity supplier to recover any fixed costs associated with your meter, such as Meter Operator charges.
Unit Rate The Unit Rate is mainly made up of the price for buying electricity on the wholesale market, transmitting the electricity to your meter and environmental charges.