How do half-hourly metering and DUoS charges affect your business?

Half-hourly data helps you see when your business uses electricity, while DUoS charges recover distribution network costs. Metering alone does not tell you which charges your supply contract passes through. Ofgem identifies 7 May 2027 as the supplier migration deadline for market-wide half-hourly settlement [S1]. Check your own contract and capacity separately. Checked October 2026.

Last checked 16 October 2026

What is half-hourly metering and why does the data matter?

Half-hourly metering records electricity use in intervals rather than showing only a total between readings. Market-wide half-hourly settlement, or MHHS, changes how electricity use is allocated in the market. Ofgem’s P487 decision confirms the supplier migration requirement [S1]. Ask your supplier what this means for your own meter and associated services.

For a charging project, request an export of your consumption data before choosing equipment. You want to see when the building is busy, not just its annual energy use. Give the designer operating hours, known shutdowns and changes planned for production, heating or catering. Mark any periods when your business was not trading normally so they are not mistaken for spare capacity.

Use the load profile explainer to organise the data request. Include units and timestamps. A kilowatt, or kW, measures power; a kilowatt-hour, or kWh, measures energy. In an illustrative half-hour interval, 20 kWh divided by 0.5 hours gives 40 kW average power. This arithmetic describes an average, not every short peak within that interval.

What are DUoS charges?

Distribution Use of System, or DUoS, charges recover costs of the local electricity network. Your distribution network operator, or DNO, runs that network. Distribution charges include a residual component recovered through fixed daily charges, which is distinct from the cost of obtaining a connection [S2].

Ask your supplier how your contract treats network charges: included in the quoted rates, passed through separately, or subject to specified adjustments. Keep its written answer with the tariff comparison. A low unit rate is not enough to compare offers if the other charges differ.

Request a complete cost schedule before using a headline price in the charger business case. Use the business electricity price guide to prepare questions for the supplier.

How do DUoS time bands affect charging costs?

Applicable network tariffs can include time-banded unit charges, fixed charges and capacity-related charges. The East Midlands published statement shows these components and their charging units [S4]. It is a regional example, not a rate card for every business in the country.

The network publishes separate regional charging statements [S3]. Match the tariff and year to your supply. Then ask the supplier which components your contract exposes you to. Moving demand to another period only changes your bill where the charging arrangement rewards that change. A meter recording intervals does not, by itself, prove the saving.

For an illustration, assume you can move 100 kWh into a period that is 4 pence per kWh cheaper under your contract. The variable-cost difference is 100 × £0.04 = £4 for that event. These are assumed inputs, not quoted rates. Subtract any added costs before treating the difference as useful. Check that vehicles still meet their departure requirements and that shifted demand fits the agreed supply capacity.

Why can a half-hourly meter have a high standing charge?

Ask for the components rather than attributing the entire bill to the meter. National Grid Electricity Distribution explains that non-domestic residual charging bands depend on the relevant site category and that capacity changes do not automatically change the residual band [S2]. Investigate the actual allocation before assuming lower energy use should reduce every fixed charge.

Request the connection agreement, current capacity and tariff information. Compare them with the demands your business now places on the site. If you occupy premises previously used for a different activity, ask for an assessment of the present arrangement rather than copying the previous occupier’s assumptions.

Read the agreed capacity guide before requesting a reduction. Have your electrical designer include planned chargers and future operational needs in that assessment. Ask the network and supplier to explain any application costs and ongoing charge changes before accepting them.

How should you model chargers, solar and batteries together?

Build the comparison around the electricity flowing through the billed connection. List the building demand, charging demand and any existing generation separately. Ask for an interval model that shows what changes under the proposed project, using the applicable supply contract rather than a generic market price.

Keep fixed and variable components separate. Do not count the same network charge as both part of an all-in energy rate and an additional cost. If the project needs extra capacity, request a revised recurring-cost estimate: UK Power Networks explicitly warns that adding power can change ongoing DUoS charges [S5].

For battery proposals, request the energy lost in charging and discharging, usable capacity and recurring costs in the calculation. For solar, distinguish energy used on site from exported energy. Our solar self-consumption guide explains that comparison. Ask your accountant to review tax treatment separately from the operating-cost model.

What should you do next?

Collect your electricity contract, recent bills, capacity agreement and interval data, then get matched with an installer that covers your area. Request a design and cost model using those records rather than a national standing-charge assumption.

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