What are DUoS and TUoS charges on a business electricity bill?

Last reviewed 2 September 2026 by Utilities Made Simple · independent, whole-of-market, supplier-paid — how we are paid

Where they sit on the bill

On a fully fixed contract they are baked into your unit rate and you never see them. On a pass-through or half-hourly contract they appear as separate lines, which is why half-hourly bills look so much more complicated even when the underlying cost is similar.

What drives the size of them

• Where you are. DUoS rates differ by distribution region, so the same business pays a different network cost in Leicester than in London.
• When you use power. DUoS has red, amber and green time bands on half-hourly supplies. Red-band units, typically late afternoon on winter weekdays, cost several times the green rate.
• Your capacity. Half-hourly sites also pay for their agreed available capacity in kVA whether they use it or not — see capacity charges and kVA explained.

Can you reduce them?

Partly, and only on half-hourly supplies. Shifting flexible load out of the red band lowers DUoS directly. Right-sizing available capacity lowers the capacity element. Neither is available to a standard non-half-hourly SME meter, where the network cost is simply part of the rate.

What you can always do is make sure you are not paying an inflated energy element on top of a network cost you cannot change. The network part is regulated and identical for everyone in your position; the supplier's margin is not.

Ask an energy specialist

If your question is not answered above, send it to us. A specialist answers personally, normally within one working day. No sales call, no obligation — and if the answer is "your deal is fine", that is what you will get.