DUoS red, amber and green bands: how timing drives your bill

Distribution Use of System (DUoS) charges pay for the local electricity network that carries power to your site. On a half-hourly bill, the unit part of DUoS is charged at different rates depending on the time of day, so when you use electricity can matter as much as how much you use. This guide explains the red, amber and green bands, how to find the times for your region and how to move load out of the expensive periods.

Key points

• DUoS includes unit rates in red, amber and green bands, a fixed daily charge, a capacity charge per kVA, excess capacity charges and reactive power charges.
• Red is the most expensive band, covering weekday late afternoons and early evenings.
• Each of the 14 Distribution Network Operator regions sets its own band times every year.
• Shifting load out of the red band reduces the time-based part of your DUoS costs.

What DUoS charges are

Great Britain is split into 14 distribution regions, each run by a Distribution Network Operator (DNO). The DNO charges your supplier for using its network, and your supplier passes that cost on to you, either built into an all-inclusive rate or shown as separate lines on your bill. For a half-hourly site, DUoS is usually made up of:

• unit rates in pence per kWh, split into red, amber and green time bands;
• a fixed charge per day;
• a capacity charge per kVA of Agreed Supply Capacity, per day;
• excess capacity charges if your demand goes over that capacity;
• reactive power charges in kVArh if your power factor is poor.

This guide focuses on the time bands. Capacity is covered in our guide to agreed supply capacity.

Red, amber and green explained

• Red is the most expensive band. It covers weekday late afternoon and early evening, usually around 16:00 to 19:00 or 16:30 to 19:30 depending on the region. This is when demand on local networks is highest.
• Amber is the shoulder band, covering weekday daytime and evening periods either side of red.
• Green is the cheapest band, covering overnight and weekends.

Red covers only a few hours on weekdays, but for many businesses those hours overlap with the end of the working day, evening trading or a second shift. That is why the red band can make up a noticeable part of DUoS costs even when relatively few units fall in it.

Why your times depend on your region

Each DNO publishes its band times and rates in an annual charging statement, so the exact hours and prices depend on where your site is connected, not where your head office is. A business with sites in several regions can have different red-band hours at each one. The distributor ID at the start of the bottom line of your MPAN tells you which region a site is in.

Distributor ID	Region	Network operator
10	Eastern	UK Power Networks
11	East Midlands	National Grid Electricity Distribution
12	London	UK Power Networks
13	Merseyside and North Wales	SP Energy Networks (SP Manweb)
14	West Midlands	National Grid Electricity Distribution
15	North East	Northern Powergrid
16	North West	Electricity North West
17	North Scotland	SSEN (Scottish Hydro Electric Power Distribution)
18	South Scotland	SP Energy Networks (SP Distribution)
19	South East	UK Power Networks
20	Southern	SSEN (Southern Electric Power Distribution)
21	South Wales	National Grid Electricity Distribution
22	South West	National Grid Electricity Distribution
23	Yorkshire	Northern Powergrid

How to find your DUoS band times

1. Find the MPAN on your bill and read the first two digits of the bottom line.
2. Match the distributor ID to your DNO using the table above, or use the Energy Networks Association's find my network operator tool.
3. Go to that DNO's website and open its current use of system charging statement.
4. Look up the time bands for your connection type and voltage. Sites connected at high voltage can be on different tariffs from low-voltage sites.
5. Check how the statement treats bank holidays.
6. Check that your bill shows units split across red, amber and green, and that the split looks right against your half-hourly data.

How timing drives your bill

You do not need a complex model to see the effect of timing. Take one month of half-hourly data and add up the kWh that fall in red-band periods, then amber, then green. Multiply each total by the matching rate on your bill. You will see how much of your DUoS unit cost comes from each band, and how much could change if some red-band load moved to amber or green.

Remember that DUoS is only one part of the bill. Some contracts also price energy differently by time of day, which can strengthen or weaken the case for shifting load. Our load profile analysis runs this calculation across all of your charges.

Practical ways to move load out of the red band

• Reschedule flexible processes. Batch production, washing, pumping and charging can often run earlier or later.
• Pre-cool or pre-heat. Cold stores and buildings can be brought to temperature before the red band starts and allowed to drift through it, within safe limits.
• Charge vehicles overnight. Set EV and forklift charging to start in the green band.
• Use battery storage. A battery can be charged at cheaper times and used to avoid red-band imports. Our guide to solar, batteries and EV charging on half-hourly sites covers this.
• Stagger start-ups. Avoid switching on large loads together at the start of the red band.

Be careful not to create a new peak. Moving a lot of load into a short window can push demand over your Agreed Supply Capacity and trigger excess capacity charges.

Does your contract pass on the saving?

On a pass-through contract, DUoS charges are passed through at cost, so moving load out of the red band shows up on your bill. On a fully fixed, all-inclusive contract, DUoS may be bundled into a single rate, so changing when you use power may not change the bill until the supplier reprices your profile at renewal. Our guide to fixed, flexible and pass-through contracts explains the differences.

Get help with DUoS charges

If you would like to know how much of your bill comes from red-band use, or whether your contract structure suits your profile, we can review your bills and half-hourly data. If we can't find a better option, we'll tell you.

Request a free bill check or call 07565 147 170.

Frequently asked questions

What time is the DUoS red band?

It depends on your region. Red is a weekday late afternoon and early evening band, usually around 16:00 to 19:00 or 16:30 to 19:30. Each of the 14 Distribution Network Operators sets its own times in an annual charging statement, so check the statement for the region shown by your MPAN's distributor ID.

Are DUoS charges the same across the UK?

No. Each of the 14 DNO regions in Great Britain sets its own DUoS rates and time bands every year, and rates can also differ by connection voltage. A business with several sites may pay different DUoS rates at each one and have different red-band hours to plan around.

Can I avoid DUoS charges completely?

No. DUoS pays for the local network, and every connected site pays it. You can reduce the time-based part by moving use out of the red band, and you may reduce capacity costs if your Agreed Supply Capacity is set too high. The fixed daily charge still applies.