On this page you will find all of the Triad data documents as well as links to guidance materials.
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.
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ESO Charging communications include:
- relevant updates about our charging, forecasting and billing activities,
- invitations to attend our forums, webinars and workshops,
- links to our published guidance materials.
Triad data 2014-2023
Here is the Triad data for 2014-2023
Name | Published |
---|---|
2022_23 Triad Data | 3 Apr 2023 |
2021-22 Triad Data | 29 Mar 2022 |
2020-21 Triad Data | 26 Mar 2021 |
2019-20 Triad Data | 26 Mar 2020 |
2018-19 Triad Data | 26 Mar 2019 |
2017-18 Triad Data | 22 Mar 2018 |
2016-17 Triad Data | 27 Mar 2017 |
2014-15 Triad Data | 27 Mar 2015 |
2015-16 Triad Data | 24 Mar 2016 |
Triad Dates | 19 Mar 2015 |
Triad data pre-2014
Here is the Triads data pre-2014.

Transmission Network Use of System (TNUoS)
Transmission Network Use of System (TNUoS) charges recover the cost of installing and maintaining the transmission system in England, Wales, Scotland and Offshore.