Gemini Re-platforming (GRP) Overview Gas Transmission Forum September 2012

GRP Progress & Plans The GRP project was established to deliver an updated design utilising fully supported hardware and software for Gemini. GRP is replacing technology not re-writing the application; system functionality will remain ‘as is’ and the look and feel of screens will be the same as at present. The project has recently completed circa 3100 Unit & System Tests Cases UAT has commenced and is running to schedule The proposed implementation date is 9th June 2013, this date is being submitted for formal representation by the UK Link Committee on 14th September 2012 Initial estimates indicate that the Gemini System will be inaccessible for approximately 12 hours whilst the implementation cut-over plan is completed If the implementation cut-over goes to plan the system outage will be from 2am and return at 2pm on Sunday 9th June. A back-out plan has been established in the event of unforeseen circumstances where a ‘roll-back’ to ‘legacy Gemini’ is needed. An allowance 8 hours has been given to this activity and therefore if back-out is required the system will be available from 10pm at the latest.

External User Impacts External Users will be required to make minor amendments to their systems to ensure connectivity to the new Gemini environments. These changes have been document in detail in the ‘Gemini Connectivity Guide’ which will be submitted for formal UK Link Representation on 14th September 2012. It is important that each external organisation that uses Gemini register their participation in User Readiness Testing to ensure that you can access Gemini post cut-over. External User Readiness Testing will run from 21st January 2013 to 1st March2013 and Xoserve will provide the test cases that need to be executed. Users are invited to register your participation in User Readiness Testing by contacting GRPcommunications@xoserve.com by 14th September 2012.

Exit Reform The Gemini Exit System changes were successfully implemented on the 29th July 2012 Testing of the new NTS Exit Reform APIs commenced on the 20th August 2012 External User Training will commence from the 3rd September 2012 The new NTS Exit Reform regime goes live from the 1st October 2012 The first NTS Enduring Exit Capacity (NXC) invoice for October 2012 will be issued the 6th November 2012

Exit Reform Preparation for the decommissioning of the old Exit Capacity processes is underway The final Exit Capacity invoice for September 12 will be issued 4th October 12 (Nov 6th if any September overruns incurred)

Mod0376S - Proposed changes to the Enduring Annual NTS Exit (Flat) Capacity Application Window(s) Change Order 2257 received from UK Transmission to undertake detailed analysis and testing to understand what system impacts there are due to Modification 0376 Detailed analysis activities completed on the 17th August 2012 Currently in the third week of a 7 week testing period