UNC Transportation Principal DocumentDocument files listed below. General Offtake Arrangements Document Transportation Principal Document European Interconnection Document Independent Gas Transporter Arrangements Document Code Updates Printer friendly version Related Files File 25 February 2026 Transportation Principle Document (Consolidated, printable version) File 01 June 2017 TPD Front Cover File 01 April 2017 TPD Table of Contents File 15 September 2025 TPD Section A - System Classification File 22 December 2025 TPD Section B - System Use and Capacity File 15 September 2025 TPD Section C - Nominations File 22 December 2025 TPD Section D - Operational Balancing and Trading Arrangements File 15 September 2025 TPD Section E - Daily Quantities Imbalances and Reconciliation File 15 September 2025 TPD Section F - System Clearing, Balancing Charges and Neutrality File 25 February 2026 TPD Section G - Supply Points File 01 October 2024 TPD Section H - Demand Estimation and Demand Forecasting File 15 September 2025 TPD Section I - Entry Requirements File 13 April 2023 TPD Section J - Exit Requirements File 29 March 2023 TPD Section K - Operating Margins File 20 May 2025 TPD Section L - Maintenance and Operational Planning File 25 February 2026 TPD Section M - Supply Point Metering File 29 March 2023 TPD Section N - Shrinkage File 20 May 2025 TPD Section O - System Planning File 09 September 2024 TPD Section Q - Emergencies File 29 March 2023 TPD Section R - Storage File 09 September 2024 TPD Section S - Invoicing and Payment File 01 April 2017 TPD Section U - Not Used File 25 February 2026 TPD Section V - General File 09 September 2024 TPD Section X - Energy Balancing Credit Management File 20 May 2025 TPD Section Y - Charging Methodologies Download All Files