Charging policy and guidance

The methodology we use to set Transmission Network Use of System (TNUoS) tariffs and charges is in the Connection and Use of System Code (CUSC), Section 14, Part 2. The general methodology for TNUoS is in CUSC Sections 3 and 13.  On this page, you will find more about consultations, policy decisions, guides, and Triads data. 

Charging methodology policy decisions

These are policy decisions documents relating to TNUoS charging methodology that are not codified within the CUSC.

Industry information guides

The following documents are designed to give you a better understanding of electricity generation charges and related topics.

Open letter consultations and guidance

These documents are open letters and informal consultations relating to TNUoS charging methodology as codified in the CUSC.

Published Sort ascending Name
Compliance with European Regulation 838/2010 Open Letter
Reflecting variations in Offshore Transmission Owner (OFTO) revenue in Offshore Local TNUoS Tariffs_v2
Guidance on the impact of Locational Transmission losses on transmission charges
Guidance on how transmission connected storage is currently charged today
Potential Transmission Charging Arrangements at Exporting Grid Supply Points - Update letter
Consolidated responses to open letter consultation
Response to Anticipatory Investment open letter - EDF
Response to Anticipatory Investment open letter - Western Isles Council
Response to Anticipatory Investment open letter - HIE
Response to Anticipatory Investment open letter - SPR
Response to Anticipatory Investment open letter - Uisenis
Response to Anticipatory Investment open letter - EOn
Response to Anticipatory Investment open Letter - FOL
Response to Anticipatory Investment open letter - Sc Renewables
Response to Anticipatory Investment open letter - GDF
Addendum to Informal Consultation
Anticipatory Investment guidance letter May 2015
Informal Consultation on Potential Transmission Charging Arrangements at Exporting Grid Supply Points
Blue Transmission Response
DONG Energy Response
Transmission Investment response
Balfour Beatty Response
Conclusions Letter on GFAI User Commitment April 2015 v1_0
ENA_OFTO_Forum_Response
Open Letter on Options for Treatment of Western Isles Anticipatory Investment in TNUoS Charging Methodology
Open Letter on GFAI User Commitment June 2014

Industry seminar slides

Triads

 

Triads are the three half-hour settlement periods with highest system demand and we use them to determine charges for demand customers with half-hour metering and payments to licence-exempt distributed generation.  They can occur in any half-hour on any day between November to February inclusive but are separated from each other by at least ten full days. Triads are determined after the event using Elexon settlement metering data from November to February. This data is usually available around 24 March after which we will confirm the Triad half-hours.  Once confirmed they are not updated for subsequent settlement data.  Indicative Triads based on data received to date can be found on Elexon's Electricity Data Summary.