tCSNP Refresh methodology
The tCSNP is our recommendation for which reinforcement projects should receive investment during the coming year to facilitate the development of an efficient, coordinated, and economical system of electricity transmission that meets environmental objectives. This must be consistent with the National Electricity Transmission System Security and Quality of Supply Standard (NETS SQSS), as well as the development of efficient interconnection capacity.
The tCSNP methodology describes how we assess the required levels of network transfer, the options available to meet this requirement and recommends options for further development. The methodology also describes the end-to-end process from the analysis to the publication of the tCSNP report and identifies the roles and responsibilities of the National Energy System Operator (NESO) and onshore Transmission Owners (TOs). Offshore transmission network developments such as the holistic network design are considered in our assessment work.
tCSNP2 Refresh methodology
The tCSNP methodology describes how we assess major National Electricity Transmission System (NETS) reinforcements and make recommendations to meet the requirements identified from the outputs of the Future Energy Scenarios (FES) and Electricity Ten Year Statement (ETYS). It also integrates with the Holistic Network Design Follow-Up Exercise (HNDFUE) that is part of the transitional Centralised Strategic Network Plan (tCSNP).
The methodology is broken down into several parts:
- Summary Methodology - Comprises of the core assessment principles and a summary of the overall process
- Annexes - Contain further detail on how each of the principles in the methodology will be assessed
- Appendices - Comprise of any technical forms used to submit any options into the process.
Our methodology annexes
Introduction
Introduction to the methodology annexes highlighting the purpose and key changes.
Annex 1 - Inputs
Information about the inputs to the options assessment process
Annex 2 - System Requirements
Covers how the GB network system requirements are identified for the options development process
Annex 3 - Options Development
Discusses how options are developed for inclusion in the options assessment process
Annex 4 - Quality Assurance Checks
Details the checks and processes to ensure data quality of options developed before options assessment process
Annex 5 - Options Assessment
Details the core options assessment process and how options are recommended
Annex 6 - Competition
Discusses how options are assessed to determine eligibility for competition
Annex 7 - Governance
Covers the governance overseeing the options assessment process
Annex 8 - Early Development of Options
Outlines early development of options and non-TO developers' process
Annex 9 - NOA for Interconnectors
Details the process for Interconnector Analysis
Our methodology appendices
Appendix A - General Roles and Responsibilities of NESO & TOs
Lists the areas of responsibility for NESO and the TOs
Appendix B - Potential transmission solutions
Appendix C - System Requirement Form
Discusses the data collected for the tCSNP2 Refresh
Appendix D - TCSNP2 Refresh key dates for 2025/26
Summarises key milestones and dates for the coming process cycle
Appendix E - Summary of Stakeholder Feedback
Summarises feedback and our responses following the public consultation of December 2024 to January 2025
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Contact us if you have a question, want to share some insight or have feedback on any part of the NOA or its methodology.
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