TNUoS charges recover the cost of installing and maintaining the transmission system in England, Wales, Scotland and Offshore.

Who does this charge apply to?

✓ Generators
✓ Suppliers
✓ Directly connected Transmission demand
✕ Distribution Network Operators
✓ Embedded Generators*
✕ Interconnectors

On this page you will find information related to TNUoS charges, such as guidance on who these charges apply to and how/when these charges are billed. Our latest and historical TNUoS publications and other relevant documentation are provided, along with ways to interact with the tariff setting process, ask questions and provide feedback.

*Certain embedded generators (<100MW) receive export payments over triad

How am I charged?

Generators are charged according to TEC (Transmission Entry Capacity). Suppliers are charged based on actual demand. All tariffs are based on which geographical zone Users are connected to.

TNUoS tariffs are published annually by 31 January and take effect from 1 April each year.



When we publish our latest forecasts of TNUoS tariffs, we are committed to holding webinars to talk through our publications and take your questions. 

We will also be holding TNUoS Tariff & Transport (DLCF ICRP) Model training sessions, details of how to sign up will be posted here.

Title Slides Webinar Date
TNUoS Tariffs August Forecast (2023/24) Download the slides Watch the webinar 22 Sep 2022
TNUoS 5-Year View Tariffs Webinar

Download the slides

Download the Q&A

Watch the webinar 14 Apr 2022
TNUoS 2022/23 Draft Tariffs webinar Download the slides Watch the webinar 14 Dec 2021
TNUoS Tariffs (2022/23 – 2026/27) 5-Year View webinar Download the slides Watch the webinar 13 Apr 2021
2021/22 Final Tariffs webinar Download the slides Watch the webinar 16 Feb 2021
2021/22 November Draft Tariffs webinar Download the slides Watch the webinar 10 Dec 2020
TNUOS tariffs and notifications of changes

TNUOS tariffs and notifications of changes

The documents below contain the TNUoS tariff forecasts and notifications of tariff changes.

Updates for next year's tariffs are published quarterly in accordance with the Connection and Use of System Code (CUSC).

TNUoS tariff model

TNUoS tariff model

We publish the DC load flow investment cost-related pricing (DCLF ICRP) transport model, which allows users to undertake their own sensitivity analysis of generation and demand tariffs under different scenarios.

If you'd like a copy of the DCLF ICRP transport model, please contact us.

For more detailed information on the DCLF ICRP, please see chapter 2 of the statement of the use of system charging methodology in section 14 of the CUSC.

Transport model inputs

Rich text

Electricity Ten Year Statement (ETYS) annual publications (appendix G – week 24 demand data & appendix F – generator TEC register) are used as key inputs for the calculation of TNUoS tariffs.

Triads data

What are triads?

Triads are the three half-hour settlement periods with highest system demand. We use them to determine charges for demand customers with half-hour metering and payments to licence-exempt distributed generation.

Want to know more?

Take a look at our guidance on triads.

Read our triads explainer

Note: indicative triads are based on data received to date can be found on Elexon's electricity data summary.

More from charging

Charging documentation

Our charging documentation page is where you can now find all of our charging statements and policy developments along with all the guidance documents and webinars you need if you're new to charging.

Contact charging

Submit a query through our webform, get involved through forums and steering groups, or reach out to the relevant charging team. 


Join our mailing list

Join our mailing list to receive publication updates, invitations to our forums, webinars and workshops, and links to our latest guidance materials.

Data Portal

Use the ESO Data Portal to gain access to TNUoS tariff datasets that are geared towards API compatibility, providing additional flexibility to end users of tariff data.