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XRN 5393
Implementation of NTS Capacity related UNC Modifications 0752S, 0759S & 0755S

Last Updated
15 Aug 2022
Release Type
Implementation Date
24 Apr 2022
Proposer National Gas Transmission Impacted DSC service area


To be confirmed

Customer Change Team Leader


0785 Application of UNC processes to an aggregated Bacton (Exit) Interconnection Point

This modification prescribes what arrangements will be applicable at the newly combined Bacton (Exit) IP after Ofgem’s decision to modify the Special Condition 9.13 of the NTS License and aggregate the Bacton Interconnection Points.  The modification will introduce aggregate arrangements for capacity processes at Bacton (Exit) IP such as competitive auctions, overruns and short haul.


Part A – 25/02/22 and Part B – 03/04/22


0752S “Introduction of Weekly Entry Capacity Auction”

The first Weekly NTS Entry Capacity auction will take place on the 20th May for Sub Transaction period Monday, 30th May – Sunday, 5th June 2022.

Rolling Monthly Trade Initiation Surrender (RMTISSEC) for June Sub Transaction period will take place on 29th April 2022. The invitation letter will be issued 2 days in advance.

Rolling Monthly Trade and Transfer of System Entry Capacity (RMTNTSEC) will take place on 11th May for the June Sub Transaction period. Allocations will be no later than the 16th May.

  • Stage 1 RMTnTSEC – moving the bid window and first allocation window forward so that they run within the first 10 business days of the monthly
  • Stage 2 RMTnTSEC – moving the second allocation so that it runs between stage 1 and the month auction batch job
  • Move the monthly batch job forward from the last gas day of the month so that it runs at least 8 days before the end of the month
  • Introduce of the weekly auction type to provide the option to purchase entry capacity in weekly strips. D will be the Monday of the auction week. Bid window to be open on D-10 and allocation on D-9.
  • Add in a weekly batch job at D-7 to occur each week after allocation
  • Introduce the ability to charge two different prices for days within the week that will span 2 gas years
  • Post implementation support


0759S “Enhancements to NTS Within-Day Firm Entry and Exit Capacity Allocations”

Users will be able to use the enhanced functionality in relation to Exit Capacity Assignments and Within Day Firm Entry and Exit products straight after implementation. 

  • Introduce hourly allocations for NTS Exit Capacity
  • Allow additional NTS entry and exit capacity allocation at 02:00
  • Extend the NTS entry and exit capacity bid invitation windows up until the time of the last allocation
  • Introduce a 30-minute capacity allocation period for NTS Exit Capacity
  • GNCC to have visibility of obligated and non-obligated quantities “waiting” to be released for both Entry and Exit (i.e. Gemini to recognise when a ASEP or Offtake has sold out of obligated baseline capacity and, prior to allocation provide visibility of additional requests for consideration).
  • Automatic release of all obligated and non-obligated bids (an on/off switch where “on” all obligated and non-obligated bids are automatically allocated subject to a threshold; “off” where non-obligated bids are held for further assessment).
  • Automatic processing of obligated bids when the bid processing automation is set to “off” rather than allocation being paused.
  • Roll over to the next auction any exit capacity restrictions put in place


0755S “Enhancement of Exit Capacity Assignments”

Users will be able to use the enhanced functionality in relation to Exit Capacity Assignments and Within Day Firm Entry and Exit products straight after implementation. 

  • Ability to assign (entitlement and liability) all or part of a Users capacity holdings at the same locations
  • Partial assignments invoiced accordingly

Impacted Customer Types

  • NGT
  • Shipper
  • DNO


Document title Comment Last updated CHMC outcome
Change Proposal Approved 29/03/2022 Approved into Capture 11/08/2021
Initial Review Stage not used N/A N/A
DSG Discussions N/A 29/03/2022 N/A
High Level Solution Options Stage not used N/A N/A
Solution Review Stage not used N/A N/A
Detailed Design Approved 29/03/2022 Detailed Design Change Pack Approved 09/03/2022
Evaluation Quotation Reports (EQR) Stage not yet reached N/A N/A
Business Evaluation Reports (BER) Approved 29/03/2022 Design Approved on 09/02/2022
Change Completion Reports (CCR) Approved 15/08/2022 CCR Approved at ChMC 10/08/2022


Initial Review
Change Proposal Raised 29/07/21
Status Awaiting ChMC approval
Approved to Capture 11/08/21
Status ChMC approved into Capture
Solution Consultation
Expected: 00/00/00
Status Stage not used
Awaiting Delivery
Expected: 00/00/00
Status Stage not used
In Delivery
BER approved 13/10/21
Status Design approved on 09/02/22
CCR Approved at ChMC 10/08/2022 24/04/22
Status Successfully Implemented

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