DUoS (Distribution Use of System)

What it is

DUoS stands for Distribution Use of System. It is the charge for the lower-voltage local network, run by your distribution network operator, that delivers electricity to your premises. It is a large part of your non-commodity costs.

Where you will see it

• As part of the unit rate and standing charge on a fixed-price quote.
• As separate lines on bills for larger sites or where the contract passes network costs through.

Why it matters

DUoS is usually made up of a fixed daily element that varies by meter type and region, plus unit charges that, for sites charged by time band, are higher at the network's busiest times. Many small sites never see this split, because the supplier folds it into a single unit rate. Sites with an agreed capacity pay a daily capacity charge too, and extra if they exceed it. That is why supply capacity and kVA matter for bigger sites.

Because the DNO sets the charge by region, two identical businesses can face different network costs. Moving some use to off-peak hours, where your meter and tariff allow it, is one way to reduce exposure. See day and night rates for how time-based pricing shows up.

Example

A bakery starts work at 4am. If its meter and contract charge by time band, much of its use may fall in cheaper periods. A shop open 9am to 6pm uses mostly at higher-rate times, so the same kWh can carry a higher network cost.

Related terms

TNUoS covers the national grid, and BSUoS covers system balancing. See also TNUoS and DUoS in plain English.