DUoS charges explained: red, amber and green bands for 2026/27

What are DUoS charges?

DUoS stands for Distribution Use of System. These charges cover the cost of installing and maintaining the local electricity distribution networks that carry electricity to homes and businesses.

They're one of several network charges built into business electricity rates. The national high-voltage network is paid for separately, through transmission charges, known as TNUoS.

This guide covers the 14 distribution areas in Great Britain, with the charges that apply from 1 April 2026 to 31 March 2027.

Who sets DUoS charges, and who pays them?

Each of the 14 areas is run by a distribution network operator, or DNO. Each one sets its own DUoS charges every year, to recover the revenue it's allowed to collect. They all use the same methods, set out in an industry agreement called the DCUSA: one for sites connected at low and high voltage, and another for the largest sites, connected at extra high voltage or metered at a high-voltage substation.

Six companies run the 14 areas:

• UK Power Networks: Eastern England, London and South East England.
• National Grid Electricity Distribution: the East Midlands, the West Midlands, South Wales and South West England.
• SP Energy Networks: Cheshire, Merseyside and North Wales, and South Scotland.
• Scottish and Southern Electricity Networks (SSEN): North Scotland and Southern England.
• Northern Powergrid: North East England and Yorkshire.
• SP Electricity North West (formerly Electricity North West): North West England.

You don't pay your network operator directly. It charges your supplier, and your supplier passes the cost on through your bill. National Grid Electricity Distribution puts it simply: "customers are not invoiced for DUOS charges by DNOs".

Some sites, often on newer developments, are connected to a smaller network run by an independent network operator, which links into the regional one. Independent network operators publish their own charges, so the figures in this guide may not match a site on one of their networks exactly.

How to find your network operator and DUoS tariff

The first two digits of the 13-digit core on the bottom row of your MPAN are your Distributor ID, and they tell you which network operator runs the wires to your premises: 10 to 23 for the 14 regional networks, and 24 or above for an independent network. Our guide to finding your MPAN shows where it is on your bill. You can also type your postcode into the Energy Networks Association's "Who's my network operator?" tool.

To find your exact tariff, you also need a code from the top row of your MPAN: the line loss factor class, or LLFC. For sites that have moved to the new market-wide half-hourly settlement arrangements, network operators use a DUoS tariff ID instead. London's network operator says that, generally, the Distributor ID and this code are all you need to identify your distribution charges in its charging statement.

DUoS time bands: red, amber and green

Each network operator splits the week into three time bands, with a separate unit rate for each:

• Red is the peak, when the local network is busiest. It falls on weekday late afternoons and early evenings (London also has a midday red period), and it's the most expensive band in every area.
• Amber covers the busy hours either side of red on weekdays. In seven areas, part of the weekend is amber too.
• Green covers the night. In the other seven areas, the whole weekend is green.

The bands are the same all year, bank holidays count as weekdays, and all times are UK clock time.

A rule change Ofgem approved in 2019 extended these three rates to every site charged under the method for low and high-voltage sites, not just half-hourly ones. In the 2026/27 charges, even the tariff for smaller business sites has red, amber and green rates. Whether the time of day affects your own bill depends on how your supplier builds network charges into your prices. As National Grid Electricity Distribution puts it, the ability to benefit "will be linked to the structure of your supply charges".

These are the 2026/27 time bands for each area. Any time not shown is green.

Red lasts three hours in most areas. It's three and a half hours in North East England and Yorkshire, two and a half in South Wales and two in South West England. London is the only area with a second red period, from 11:00 to 14:00, so it has six red hours each weekday. No area has a red period at weekends.

DUoS rates for smaller business sites in 2026/27

Most smaller business sites are on the "Non-Domestic Aggregated" tariff (listed in the 2026/27 schedules as "Non-Domestic Aggregated or CT"). It covers sites that aren't settled half-hourly, and half-hourly sites with whole-current meters, the type used for smaller supplies. It has a fixed charge per site per day, set by your site's band, and red, amber and green unit rates. There's no capacity charge.

These are the 2026/27 rates for a site in band 3, which covers sites that used between 13,677 and 27,543 kWh of electricity a year when the bands were set:

For a band 3 site, the red rate ranges from 7.992p per kWh in London to 24.204p in South West England, about three times as much. The fixed charge depends on the band, and in most areas it rises from band 1 to band 4:

These are DUoS charges only. Transmission charges and the other costs in your prices come on top. Our business energy prices page shows what businesses pay per kWh in total, from the government's figures.

Why some areas have no fixed DUoS charge

A DUoS charge has two parts. Forward-looking charges reflect the cost that a site's use puts on the network. The residual collects the rest of the revenue the operator is allowed. Since April 2022, the residual has been charged as a fixed amount per site per day, set by the site's band.

In some areas, the forward-looking charges on their own would collect more than the operator is allowed, so the residual is negative. The charging method then cuts the fixed charge, but not below zero, and takes anything left over off the unit rates.

For 2026/27, that happens in London, North West England, Southern England and North Scotland. All four list a negative residual for every low and high-voltage band, and London's schedule spells out the effect: "the application of the residual reduces the calculated fixed charge". That's why, for smaller business sites, the fixed charge in these areas doesn't rise with the band. In London and North West England it's zero in every band, so no banded smaller business site there pays a fixed DUoS charge in 2026/27. In Southern England and North Scotland it falls from band 1 to band 2 and is zero in bands 3 and 4. Where the fixed charge has reached zero, the unit rates are cut instead, so the red rate is lower in the higher bands.

So it isn't true everywhere that a bigger site pays a bigger fixed charge. In the other ten areas, though, the fixed charge rises from band 1 to band 4.

How your DUoS band is set

Your band depends on your electricity use or, for larger sites, the capacity agreed for your site in kVA:

The thresholds are set nationally, and they're the same as the bands for transmission charges. The current bands took effect in April 2026. Smaller sites were banded on their use between 1 May 2022 and 30 April 2024, and sites with an agreed capacity on their average capacity over the same 24 months.

A site normally stays in its band until the bands are next reviewed. It can be moved only in limited cases, for example after a 50% rise or fall in its capacity or use. If you don't know your site's band, ask your supplier.

DUoS charges for larger sites: capacity and reactive power

Larger sites that are settled half-hourly and have current transformer (CT) metering are on "site-specific" tariffs. They have a half-hourly meter and usually an agreed capacity. On top of the fixed charge and the red, amber and green unit rates, they pay:

• a capacity charge, in pence per kVA per day, on the site's agreed Maximum Import Capacity, or MIC;
• an exceeded capacity charge, on any capacity used above the MIC;
• a reactive power charge, in pence per kVArh, on any reactive power above 33% of active power in a half hour, a threshold equivalent to an average power factor of 0.95.

Half-hourly sites with whole-current meters are on the aggregated tariff instead, so they don't pay capacity or reactive power charges. Some site-specific sites with transitional protection, linked to changes in how half-hourly sites are settled, are billed only fixed and unit charges for the time being, like sites on aggregated tariffs.

These are the 2026/27 charges for low-voltage site-specific tariffs:

For these low-voltage site-specific tariffs, the 2026/27 exceeded capacity rate is the same as the capacity rate in every area.

Working out a site's DUoS cost: an example

Take a band 3 site in Eastern England that uses 20,000 kWh a year: 2,000 kWh in the red band, 13,000 kWh in amber and 5,000 kWh in green. At the 2026/27 rates, its DUoS charges come to:

• red: 2,000 kWh at 11.716p, £234.32;
• amber: 13,000 kWh at 1.442p, £187.46;
• green: 5,000 kWh at 0.184p, £9.20;
• fixed charge: 10.82p a day for 365 days, £39.49.

That's about £470 for the year. If the site moved 1,000 kWh of its use from red to amber, its DUoS charge would be about £103 lower.

A site on a low-voltage site-specific tariff in Eastern England whose agreed capacity has been 100 kVA throughout is in band 2. Its capacity charge alone is 8.04p per kVA a day on 100 kVA, about £2,935 a year, plus a fixed charge of 33.09p a day, about £121 a year, before any unit charges.

These are the charges your supplier pays for your site. What you pay depends on how your supplier builds them into your prices.

How DUoS shows on a business electricity bill

You're unlikely to see DUoS as its own line on a standard business bill. Your supplier pays it and builds it into your prices, and Ofgem says suppliers are free to set their own standing charges and unit rates. That's why the network part of your bill can sit in your standing charge, your unit rates or both.

• On a fixed-rate contract, Ofgem says your unit rates and standing charges are fixed for the length of the contract.
• On a pass-through contract, some network costs are passed on at cost, so they can change during the contract, for example each April.

If your bill does list network charges separately, our guide to reading a business electricity bill explains the other lines you may see.

For households, National Grid Electricity Distribution says DUoS is typically about 17% of the final bill. It gives no figure for businesses.

Can you reduce your DUoS charges?

Network operators point to three things:

• Use less in the red band. National Grid Electricity Distribution says the most effective way to cut energy charges is to use less, "particularly in the peak periods". You'll only see the difference if your supplier's prices reflect when you use electricity.
• Check your agreed capacity. If your MIC is higher than you need, you can ask your network operator to lower it. National Grid Electricity Distribution allows one change in any 12 months and doesn't charge for a reduction, but capacity you give up can go to others, and you may have to pay to increase it later. UK Power Networks says reductions take effect from the first of the following month and can't be backdated. Our guide to kVA capacity charges explains how to check yours.
• Fix a poor power factor. Electric motors, transformers and fluorescent lighting can all cause a poor power factor. Keeping it between 0.95 and 1, with the right equipment or a power factor correction unit near the meter, generally avoids reactive power charges, which only apply to sites on site-specific tariffs.

When DUoS charges change

DUoS charges change every year on 1 April, and network operators usually publish them 15 months in advance. Each December, they set the charges for the year that starts on 1 April 15 months later. In October 2025, Ofgem turned down a permanent cut to 14 months. In October 2026, it decided to keep 15 months for 2028/29, the first year of the next price control for the distribution networks, and to cut it to 14 months for 2029/30.

That means the charges for 2027/28, from 1 April 2027, have already been published, and those for 2028/29 are due in December 2026. Ofgem can allow a delay: for 2027/28, it let National Grid Electricity Distribution publish its final charges for the East Midlands and West Midlands by 27 February 2026. We'll update this guide with the 2027/28 figures before they take effect.

One proposal could change how some bands work. Ofgem is minded to reject DCP412, a change that would move business sites with a high agreed capacity but low use into a lower band, which would reduce their fixed network charges. Its consultation closes on 11 December 2026, and it aims to decide before 20 January 2027.