On this page you will find consultation documents and policy developments and decisions.

The methodology we use to set tariffs and calculate charges is in the Connection and Use of System Code (CUSC), Section 14. 

Charging methodology policy decisions

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

Name Published
TNUoS Onshore Locational Security Factor Consultation - Decision 4 Jan 2021
Inv Ahead of TEC Guidance Document V1_0-V2_0 track changes 23 Oct 2017
Inv Ahead of TEC Guidance Document V2_0 23 Oct 2017
Open letter responses 23 Oct 2017
Inv Ahead of TEC Guidance Document V2.0 draft 7 Aug 2017
Delay Charge Open Letter 24 Jun 2015
Investment Ahead of TEC Guidance Document 24 Jun 2015

Open letters, consultations and notices

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These documents are open letters and informal consultations relating to TNUoS charges.

Name Published
TNUoS Onshore Locational Security Factor Consultation Analysis (Excel) 4 Jan 2021
TNUoS Onshore Locational Security Factor Consultation 4 Jan 2021
TNUoS Onshore Security Factor Consultation Responses - Non Confidential (ZIP) 4 Jan 2021
Important update for those who pay securities 21 Dec 2018
Compliance with European Regulation 838/2010 Open Letter 30 May 2018
Reflecting variations in Offshore Transmission Owner (OFTO) revenue in Offshore Local TNUoS Tariffs_v2 19 Sep 2017
Guidance on the impact of Locational Transmission losses on transmission charges 4 Jul 2017
Guidance on how transmission connected storage is currently charged today 2 Mar 2017
Potential Transmission Charging Arrangements at Exporting Grid Supply Points - Update letter 4 Nov 2016
Consolidated responses to open letter consultation 19 Nov 2015