* MARKET SYSTEM RELEASE UPDATE Modifications Committee Meeting 9 August 2011 * 1##

SEM R1.10.0 – Oct. 2011 Scope for SEM R1.10.0 is as follows: Implementing this change enables: SEMO to fulfil its obligations under the Code without the need for external contracts; a rapid turnaround of the MIUN calculation, required under the tight timelines for Intra-Day Trading; and the commissioning of the new Auction Management Platform (AMP) which will result in the decommissioning of MITs in October 2011. Deployment Date October 7th, 2011, subject to successful completion of testing. Change Request Description SEM_PC_CR172 MIUN Calculation 2

SEM R2.0.0 – Intra-Day Trading - Scope Scope for SEM R2.0.0 is as follows: Release cut-off date was Friday, August 5th, 2011 No further changes anticipated. As at the cut-off date there were: No additional approved Modification Proposals that could be accommodated due to vendor capacity constraints; and No additional Non T&SC Change Requests submitted to the SDS. Our vendors have indicated that there is little scope for including additional changes within the Intra-Day Trading release. Any subsequent approved change will be included within the next release where capacity is available as per the agreed process. Change Request Mod Ref Description SEM_PC_CR222 18_10 Intra-Day Trading SEM_PC_CR256 43_10 Variable Price Taker Generator Units and Firm Access 3

SEM R2.0.0 – Intra-Day Trading – Project schedule Key milestones of the project were communicated: By the SEMO helpdesk to all Participants on July 1st; At the Market Operator User Group (MOUG) meeting of July 19th; and At a dedicated meeting for the industry hosted by SEMO on August 3rd. Major activities and associated schedule for the project are as follows: * subject to successful completion of testing Activity Schedule Status Detailed Requirements Dec 1st , 2010 – Apr 30th, 2011 Complete Vendor Detailed Design May 1st, 2011 – Jul 29th, 2011 Design Deliverables Issued to Participants (MPUD etc.) Aug 29th, 2011 In Progress Vendor Implementation Jun 20th, 2011 – Nov 11th, 2011 Factory Testing Nov14th, 2011 - Dec 23rd, 2011 System Integration Testing Jan 3rd, 2012 - Apr 27th, 2012 Market Trial Apr 30th, 2012 – Jul 6th, 2012 Deployment Jul 20th, 2012* 4

SEM R2.0.0 – Intra-Day Trading – Current Status Currently the project is on schedule across all workstreams A detailed communications plan will be published in the coming weeks to ensure efficient and effective communications for the project duration: Programme Management Forum (PMF) meetings / conference calls; Dedicated Design workshops; Updates to Modifications Committee; Updates to the Market Operator User Groups (MOUG); and Regular updates on the SEMO website. 5

Friday, November 18th, 2011 SEM R2.1.0 – October 2012 The release cut-off date for the October 2012 release to the Central Market Systems is Friday, November 18th, 2011 All approved Modifications Proposals will be allocated to this release (subject to available capacity). 6