Distribution Use of System

DUoS charges are paid by electricity suppliers to the regional Distribution Network Operator (DNO) — the company that owns and runs the local low- and high-voltage wires that take power from the national transmission system to your meter. There are six DNO regions covering Great Britain (UK Power Networks, Western Power Distribution / National Grid Electricity Distribution, Northern Powergrid, Electricity North West, SP Energy Networks, SSEN). Each DNO publishes its own DUoS tariff which is approved annually by Ofgem.

For half-hourly customers, DUoS is recovered through three time-of-day bands:

• Red — peak weekday evenings, the most expensive band; designed to incentivise demand reduction at network peak.
• Amber — shoulder periods.
• Green — overnight and weekend, the cheapest band.

For non-half-hourly profile-class customers, DUoS is bundled into a single unit rate without time-of-day banding. Following the Targeted Charging Review, the residual element of DUoS for HH customers is now recovered through fixed bands rather than volumetric charges, leaving only the forward-looking, locational-signal element of DUoS subject to Red/Amber/Green time-of-day pricing.

For procurement, the practical implications are: shifting load from Red to Amber/Green can produce material DUoS savings on HH supplies; and an HH site's residual TCR band is set by its measured demand history, so capacity planning has knock-on effects on this fixed component for years.