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

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

What's on this page

How am I charged?


Latest news & updates

TNUOS tariffs & notifications of changes

Learn more about the TNUoS charges

TNUoS Data

Additional help and support

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. 

Click on our upcoming and recent webinars to register or view the presentations and access the webinar recordings. We will also be holding TNUoS Tariff & Transport (DLCF ICRP) Model training sessions, details of how to sign up will be posted here.

2021/22 Final Tariffs webinar recording and slides

Report Published: January 2021 Webinar: 16 February 2021

2021/22 November Draft Tariffs webinar recording and slides

Report Published: November 2020 Webinar: 10 Dec 2020

2021/22 – 2025/26 5-Year View webinar recording and slides

Report Published: August 2020 Webinar: 10 Dec 2020

Latest news and updates

TNUoS Tariffs April 5-Year View published

We have recently published our 5 Year-view (2022/23 – 2026/27) on TNUoS Tariffs – go to the TNUoS tariffs and notifications of changes section.

ESO 2021/22 Charging Statement published

The ESO Charging statement ‘Issue 3 revision 0’ for charging year commencing 1 April 2021 has been published.

Timetable of TNUoS forecast for 2022/23 updated

The timetable for our 2022/23 TNUoS tariff publications during 2021/22 has been updated.

TNUOS tariffs & 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).

Tariff forecasts - current

Learn more about TNUoS 


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.


Charging Guidance

On this page you will find guidance materials to help you understand how, when and what you'll be charged.


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


Triads Data

Triads are the three half-hour settlement periods with highest system demand. Learn more about Triads and access related data and guidance materials

Additional help and support


Charging guidance

Access a range of guidance materials to help you understand how, when and what you’ll be charged.


TNUoS enquiries

Contact us directly to raise a query relating to TNUoS and our publications, or to provide feedback. Please note our usual contact number is currently unmanned due to COVID-19 homeworking.


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.