Five-Year View of TNUoS Tariffs for 2021/22 to 2025/26 National Grid Electricity System Operator August 2020 Five-Year View of TNUoS Tariffs for 2021/22 to 2025/26 | Error! No text of specified style in document. 0 Contents Executive Summary ............................................................................................... 4 Forecast Approach ................................................................................................. 7 Generation tariffs ................................................................................................. 11 1. Generation tariffs summary ....................................................................................................... 12 2. Generation wider tariffs.............................................................................................................. 12 3. Changes to wider tariffs over the five-year period ..................................................................... 16 Onshore local tariffs for generation ...................................................................... 19 4. Onshore local substation tariffs ................................................................................................. 19 5. Onshore local circuit tariffs ........................................................................................................ 20 Offshore local tariffs for generation ...................................................................... 23 6. Offshore local generation tariffs ................................................................................................. 23 Demand tariffs ...................................................................................................... 24 7. Demand tariffs summary............................................................................................................ 25 8. Forecast Tariffs for 2021/22....................................................................................................... 26 9. Half-Hourly demand tariffs ......................................................................................................... 27 10. Embedded Export Tariffs (EET) ................................................................................................ 29 11. Non-Half-Hourly demand tariffs ................................................................................................. 31 Overview of data input ......................................................................................... 33 12. Changes affecting the locational element of tariffs .................................................................... 34 13. Adjustments for interconnectors ................................................................................................ 34 14. Expansion Constant ................................................................................................................... 35 15. Locational onshore security factor ............................................................................................. 35 16. Onshore substation .................................................................................................................... 36 17. Offshore local tariffs ................................................................................................................... 36 18. Allowed revenues ...................................................................................................................... 36 19. Generation / Demand (G/D) Split .............................................................................................. 37 20. Charging bases for 2021/22- 2025/26 ....................................................................................... 38 21. Annual Load Factors .................................................................................................................. 39 22. Generation and demand residuals ............................................................................................ 39 Sensitivity Analysis............................................................................................... 42 23. Transmission Generator Residual Sensitivities ......................................................................... 43 24. Onshore TOs revenue sensitivity .............................................................................................. 45 25. Generation zoning sensitivity ..................................................................................................... 46 26. Remote island sensitivity ........................................................................................................... 49 27. Small Generator Discount sensitivity ......................................................................................... 51 Tools and supporting information ......................................................................... 52 Further information ............................................................................................... 53 Appendix A: Background to TNUoS charging ...................................................... 54 Appendix B: Changes and proposed changes to the charging methodology ....... 60 August 2020 | Five Year View of TNUoS Tariffs for 2021/22 to 2025/26 1 Appendix C: Breakdown of locational HH and EE tariffs ...................................... 63 Appendix D: Locational demand profiles .............................................................. 68 Appendix E: Annual Load Factors ........................................................................ 70 Appendix F: Contracted generation ..................................................................... 72 Appendix G Transmission company revenues ..................................................... 87 Appendix H: Generation zones map .................................................................... 94 Appendix I: Demand zones map .......................................................................... 96 Appendix J: Changes to TNUoS parameters ....................................................... 98 List of Tables and Figures Table 1 Assumptions ......................................................................................................................... 9 Table 2 Summary of average generation tariffs .............................................................................. 12 Table 3 Generation wider tariffs in 2021/22 .................................................................................... 13 Table 4 Generation wider tariffs in 2022/23 .................................................................................... 14 Table 5 Generation wider tariffs in 2023/24 .................................................................................... 14 Table 6 Generation wider tariffs in 2024/25 .................................................................................... 15 Table 7 Generation wider tariffs in 2025/26 .................................................................................... 15 Table 8 Comparison of Conventional Carbon (80%) tariffs............................................................. 16 Table 9 Comparison of Conventional Low Carbon (80%) tariffs ..................................................... 17 Table 10 Comparison of Intermittent (40%) tariffs .......................................................................... 18 Table 11 Local substation tariffs ...................................................................................................... 20 Table 12 Onshore local circuit tariffs ............................................................................................... 20 Table 13 Circuits subject to one-off charges ................................................................................... 22 Table 14 Offshore local tariffs 2021/22 ........................................................................................... 23 Table 15 HH, NHH and EET Summary ........................................................................................... 25 Table 16 Non-Locational banded charges ...................................................................................... 26 Table 17 HH, NHH and EET Summary (2021/22 Forecast variation) ............................................. 26 Table 18 Gross Half-Hourly locational demand tariffs by demand zone (5-year view) ................... 27 Table 19 Half-Hourly demand tariffs (2021/22 Forecast variation) ................................................. 28 Table 20 Embedded Export Tariffs 2021/22 to 2025/26 ................................................................. 29 Table 21 Embedded Export Tariffs (2021/22 Forecast Variation) ................................................... 30 Table 22 Non-half hourly demand tariffs from 2021/22 to 2025/26 ................................................. 31 Table 23 Non-Half-Hourly demand tariffs (2021/22 Forecast Variation) ......................................... 32 Table 24 Generation contracted, modelled and chargeable TEC ................................................... 34 Table 25 Interconnectors ................................................................................................................. 35 Table 26 Expansion Constant ......................................................................................................... 35 Table 27 Allowed revenues ............................................................................................................