Transmission Network Use of System (TNUoS) Charges
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
Here you will find detailed information on TNUoS charges, including guidance on who they apply to, and how and when they 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 Transmission Entry Capacity (TEC), while suppliers are charged based on actual demand. Tariffs are based on which geographical zone users are connected to.
NESO publishes the TNUoS tariffs annually by 31 January to take effect from 1 April each year.
Latest news and updates
Events
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 July Forecast (2025/26) | 17 Oct 2024 | ||
| TNUoS Tariffs Five-Year View for 2025/26- 2029/30 | Download the Q&A | 15 May 2024 | |
| TNUoS Tariffs August Forecast (2023/24) | Download the slides | Watch the webinar | 22 Sep 2022 |
| TNUoS 5-Year View Tariffs Webinar | 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
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).
2025/26 Tariff Publications
2024/25 Tariff Publications (Current year tariffs)
2023/24 Tariff Publications
2022/23 Tariff Publications
2021/22 Tariff Publications
Tariff Publications - Archive (Pre 2021/22)
| Name | Published Sort ascending |
|---|---|
| 2017-2018 TNUoS Forecast Timetable | 2 Sep 2017 |
| Quarterly Forecast 2018-19 - June 2017 | 6 Jul 2017 |
| Quarterly Forecast 2018-19 - June 2017 - Tables | 30 Jun 2017 |
| Revised Timetable of TNUoS Tariff Forecasts for 2018-19 | 21 Jun 2017 |
| Forecast From 2017-18 to 2021-22 - Tables - with CMP264_265 Calculator | 20 Mar 2017 |
| Forecast From 2017-18 to 2021-22 | 28 Feb 2017 |
| Forecast From 2017-18 to 2021-22 - Tables | 28 Feb 2017 |
| Final tariffs 2017-18 v1 | 31 Jan 2017 |
| Final ALFs Report for 2017-18 | 25 Jan 2017 |
| Final Tariffs 2017-18 - Tables EXTERNAL | 2 Jan 2017 |
5-Year View Tariff Publications
Tariff change notifications
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
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.
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.
Note: indicative triads are based on data received to date can be found on Elexon's electricity data summary.
Triad data 2014-2023
Here is the Triad data for 2014-2023
Triad data pre-2014
Here is the Triads data pre-2014.
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 NESO Data Portal to gain access to TNUoS tariff datasets that are geared towards API compatibility, providing additional flexibility to end users of tariff data.