Half-Hourly Electricity Meters Explained
Understand how half-hourly consumption data supports billing, procurement and energy management for larger or more complex business sites.
What Half-Hourly Metering Means
Half-hourly (HH) metering is a method of recording electricity consumption in 48 individual settlement periods of 30 minutes each, across every 24-hour day. Rather than recording a single cumulative reading over a billing period, a half-hourly meter captures how much electricity was consumed in each distinct 30-minute window.
This granular consumption data is transmitted automatically to the relevant data services and is used for billing, network settlement and energy management purposes. It provides a detailed picture of how and when electricity is used at a supply point, rather than simply how much was used in total.
Half-hourly metering is associated with larger or more complex commercial electricity supplies, though the precise circumstances in which it applies have evolved over time and continue to change as UK settlement arrangements develop. If you are unsure whether your supply is half-hourly metered, the most reliable way to confirm is to check your MPAN or contact your current supplier.
This diagram is illustrative only. Actual consumption patterns vary by business type, operating hours and season.
How Consumption Is Recorded in Settlement Periods
Each 30-minute interval in a day is referred to as a settlement period. There are 48 settlement periods in a standard day, numbered from period 1 (00:00 to 00:30) through to period 48 (23:30 to 00:00). On days when the clocks change, there may be 46 or 50 settlement periods.
The electricity consumed during each settlement period is measured in kilowatt-hours (kWh) and recorded by the meter. This data is collected and processed by the relevant data services, then used to calculate the charges due for each period based on the applicable contract rates.
For businesses on half-hourly contracts, the unit rate charged may vary by time of day or by settlement period, depending on the contract structure. This means that the time at which electricity is consumed can affect the cost, making consumption profile data particularly relevant to procurement and cost management decisions.
On days when the clocks change, there may be 46 or 50 settlement periods rather than the standard 48. This is accounted for in the settlement process.
How to Recognise a Half-Hourly Supply
There are several indicators that a business electricity supply may be half-hourly metered:
MPAN profile class
The Meter Point Administration Number (MPAN) contains a profile class indicator in its top line. Profile classes 00 is associated with half-hourly metered supplies. However, the relationship between profile class and metering arrangements is subject to ongoing change under Market-wide Half-Hourly Settlement (MHHS) developments. Always verify with your supplier or meter operator rather than relying solely on the profile class digit.
Meter type at the premises
A half-hourly supply will have a meter capable of recording and transmitting interval data. If you are unsure what type of meter is installed at your premises, your current supplier or meter operator can confirm this.
Your current energy bill or contract
Your electricity bill or contract documentation may indicate whether your supply is settled on a half-hourly basis. Look for references to half-hourly data, interval metering or profile class 00 in your contract or bill.
Maximum demand above certain levels
Supplies where the recorded maximum demand has exceeded certain thresholds have historically been required to use half-hourly metering. The specific thresholds and requirements have changed over time and continue to evolve. If your business has significant electricity demand, it is worth confirming your metering arrangements with your supplier.
Metering arrangements are subject to ongoing change under the Market-wide Half-Hourly Settlement (MHHS) programme. Always verify your current metering status with your supplier or meter operator rather than relying solely on historical indicators such as profile class.
Relationship Between the Meter, MPAN and Consumption Data
The MPAN (Meter Point Administration Number) is the unique identifier for your electricity supply point. It remains associated with the supply point regardless of which meter is physically installed or which supplier provides the electricity. The MPAN is the reference used by all parties in the supply chain — the supplier, the network operator, the meter operator and the data services — to identify and exchange data about your supply.
The meter itself records the consumption data. For a half-hourly supply, the meter captures interval data for each 30-minute settlement period and makes this available for collection by the appointed Data Collector. The Data Collector processes the raw meter data and passes it to the Data Aggregator, which compiles it for use in the settlement process.
The consumption data associated with your MPAN is used by your supplier to calculate your bills and by the network operator to manage the distribution network. It may also be used by your energy consultant or broker to analyse your consumption profile and identify opportunities to reduce costs or improve efficiency.
Meter
Records 48 periods/day
Data Collector
Collects & validates
Data Aggregator
Compiles for settlement
Supplier
Bills & manages position
This is a simplified illustration of the data flow. Actual arrangements involve additional parties and processes governed by the Balancing and Settlement Code (BSC).
Why Larger Businesses May Use Half-Hourly Metering
Half-hourly metering has historically been associated with larger electricity consumers, partly because the granular data it provides is more relevant to the billing and settlement of supplies with significant and variable demand. For a business consuming relatively small and consistent amounts of electricity, a simpler metering arrangement may be sufficient.
For businesses with higher consumption or more variable demand patterns — such as manufacturing sites, large retail premises, hotels or multi-tenanted commercial buildings — half-hourly data provides a more accurate basis for billing and a more useful tool for energy management. It allows the business to understand not just how much electricity it uses, but when it uses it.
The requirements around half-hourly metering have changed over time and are continuing to evolve as the UK electricity market develops. The Market-wide Half-Hourly Settlement programme is expected to extend interval metering and settlement to a much wider range of supplies over time. Businesses should seek up-to-date guidance from their supplier or an independent energy consultant if they are uncertain about their current or future metering obligations.
Half-Hourly Data and Contract Quotations
When obtaining a contract quotation for a half-hourly metered supply, suppliers will typically request access to the half-hourly consumption data associated with the MPAN. This data allows the supplier to analyse the consumption profile — including the pattern of demand across different times of day and different days of the week — and to price the contract accordingly.
A consumption profile that shows high demand during peak periods may attract different pricing than one that shows more consistent or off-peak demand. This is because the cost of supplying electricity varies by time of day, reflecting the wholesale market price and the cost of balancing the network.
Providing accurate half-hourly data when requesting quotations helps to ensure that the prices offered reflect your actual consumption pattern. If the data used for quotation does not accurately represent your usage, the contract price may not be appropriate for your needs. Our team can assist with obtaining and presenting the relevant data when requesting quotations on your behalf.
Maximum Demand and Capacity Considerations
Maximum demand refers to the highest level of electricity consumption recorded at a supply point within a defined period — typically the highest half-hourly demand recorded in a month or year. It is measured in kilowatts (kW) or kilovolt-amperes (kVA) and is a key factor in determining the capacity of the connection required at the supply point.
The agreed capacity of your electricity connection — sometimes referred to as the agreed supply capacity or import capacity — affects the charges applied to your supply. If your actual maximum demand exceeds the agreed capacity, you may incur excess capacity charges. Conversely, if your agreed capacity is significantly higher than your actual maximum demand, you may be paying for capacity you do not use.
Half-hourly data makes it possible to identify the maximum demand recorded at a supply point and to assess whether the agreed capacity is appropriate. Reviewing maximum demand and capacity as part of the contract renewal process can help to ensure that the capacity charges on your contract reflect your actual requirements.
For detailed guidance on kVA, maximum demand and capacity charges, see our dedicated guides: kVA and Maximum Demand and Business Electricity Capacity Charges.
Meter Operator and Data Collector Roles
Several parties are involved in the metering and data services associated with a half-hourly electricity supply. Understanding their roles can help when dealing with metering queries.
Meter Operator (MOP)
The Meter Operator is responsible for installing, maintaining and testing the meter at your supply point. The MOP is appointed under a contract and is responsible for ensuring that the meter is functioning correctly and recording data accurately. If there is a fault with the meter, the MOP is the party responsible for rectifying it.
Data Collector (DC)
The Data Collector is responsible for collecting the half-hourly consumption data from the meter and processing it into a format suitable for use in the settlement process. The DC validates the data and passes it to the Data Aggregator.
Data Aggregator (DA)
The Data Aggregator compiles the processed consumption data from the Data Collector and submits it to the settlement system. The DA plays a role in ensuring that the data used for settlement accurately reflects the consumption recorded at the supply point.
Supplier
Your electricity supplier uses the consumption data provided through the metering and data services chain to calculate your bills and to manage its own position in the wholesale market. The supplier is your primary point of contact for billing queries and contract matters.
Benefits of Reviewing Consumption Profiles
One of the most practical benefits of half-hourly metering is the ability to analyse consumption profiles in detail. By examining how electricity use varies across different times of day, days of the week and seasons of the year, a business can identify patterns that may present opportunities to reduce costs or improve efficiency.
For example, consumption data may reveal that significant electricity use occurs outside normal operating hours, suggesting that equipment is left running unnecessarily. It may show that demand peaks at particular times, which could be reduced through load shifting or operational changes. It may also highlight the impact of specific equipment or processes on overall consumption.
When renewing or renegotiating an energy contract, a detailed understanding of the consumption profile can support more informed procurement decisions. It allows a business to assess whether a time-of-use tariff structure might be more cost-effective than a flat-rate structure, and to provide suppliers with accurate data for quotation purposes.
Multi-Site and Portfolio Considerations
For businesses operating across multiple sites, some supply points may be half-hourly metered while others are not, depending on the consumption levels and metering arrangements at each site. Managing a mixed portfolio requires an understanding of the different data and billing arrangements that apply to each supply point.
Where a portfolio includes half-hourly metered supplies, the consumption data available for those sites can be used to support portfolio-level energy management and procurement. Aggregating consumption profiles across multiple sites can provide a more complete picture of the business's overall electricity use and demand patterns.
Our team can assist businesses with multi-site portfolios in reviewing the metering arrangements and consumption data across their supply points, and in presenting this information to suppliers when obtaining quotations.
Market-Wide Half-Hourly Settlement
The UK electricity market is undergoing a significant change known as Market-wide Half-Hourly Settlement (MHHS). This programme, overseen by Ofgem and the industry, is intended to extend half-hourly settlement to a much wider range of electricity supply points over time, including many that are currently settled using estimated consumption profiles.
The MHHS programme is being implemented in phases and is expected to affect how consumption data is collected, processed and used for settlement across the market. The precise timeline and implications for individual businesses and supply points are subject to ongoing development.
Businesses that currently have non-half-hourly metered supplies may be affected by MHHS developments in due course. We recommend checking the latest guidance from Ofgem or your supplier for up-to-date information on how these changes may affect your supply.
For authoritative and current information on MHHS, please refer to the Ofgem website at ofgem.gov.uk or the Elexon website at elexon.co.uk, which publishes detailed information on electricity settlement arrangements in Great Britain.
Official guidance on MHHS and electricity settlement
Frequently Asked Questions About Half-Hourly Electricity Meters
Related Guides and Resources
Browse all our commercial energy guides in one place.
Read guideUnderstand the Meter Point Administration Number and what each part means.
Read guideHow kVA and maximum demand affect your electricity contract and charges.
Read guideWhat capacity charges are and how they appear on commercial electricity contracts.
Read guideHow commercial electricity pricing is structured and what affects your contract rate.
Read guideRequest a free, no-obligation business energy quote from our specialist team.
Read guideNeed Help With a Half-Hourly Electricity Supply?
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