MARKET SYSTEM RELEASE UPDATE Modifications Committee Meeting 29 May 2012

Scope for SEM R2.0.0 is as follows: SEM R2.0.0 – Intra-Day Trading – Scope Reminder Change RequestMod RefDescription SEM_PC_CR22218_10Intra-Day Trading SEM_PC_CR244SO Security (Option 1) SEM_PC_CR25643_10Variable Price Taker Generator Units and Firm Access SEM_PC_CR28418_10Data to be Utilised when MSP Software Cancellation Run occurs SEM_PC_CR287Inclusion of Breach Amount in the Credit Risk Report

Major activities and associated schedule for the project are as follows: The project is on schedule across all workstreams. * subject to successful completion of testing SEM R2.0.0 – Intra-Day Trading – Project schedule ActivityScheduleStatus Detailed RequirementsDec 1 st, 2010 – Apr 30 th, 2011Complete Vendor Detailed DesignMay 1 st, 2011 – Jul 29 th, 2011Complete Design Deliverables Issued to Participants (MPUD etc.) Aug 29 th, 2011Complete Participant Engagement Plan publishedSep 9 th 2011Complete Participant Systems Design WorkshopsSep 28 th, Oct 5 th 2011Complete Vendor ImplementationJun 20 th, 2011 – Nov 11 th, 2011Complete Factory TestingNov14 th, Dec 23 rd, 2011Complete System Integration TestingJan 3 rd, Apr 27 th, 2012Complete Market TrialApr 30 th, 2012 – Jul 6 th, 2012In Progress DeploymentJul 20 th, 2012*

The Approved scope for SEM R2.1.0 is as follows: SEM R2.1.0 – Oct – Scope Reminder Mod RefCR RefDescription Mod_40_10SEM_PC_CR254Differentiation between Dwell Times and Dwell Trigger Points While Ramping Up and Ramping Down Mod_42_10SEM_PC_CR255Changes to the Single Ramp-Up Rate and the Single Ramp-Down Rate calculation. Mod_01_11SEM_PC_CR258UI Payments for Generator Units. Mod_06_11SEM_PC_CR259Increasing maximum daily submission number and automating cancellation of Settlement Reallocation Agreements. Mod_10_11SEM_PC_CR274Interconnector Under Test. Mod_12_11SEM_PC_CR275Interconnector Unit Loss Adjustment when Exporting Mod_21_11SEM_PC_CR280UI Payments for Generator Units Constrained On SDSSEM_PC_CR207Automation of FMOC Calculation SDSSEM_PC_CR260Additional MI-AMP Feed SDSSEM_PC_CR261Removal of orphan Trading Site Settlement Points SDSSEM_PC_CR266Change of Effective Date in the MPI SDSSEM_PC_CR267Wind and Load Forecast Data SDSSEM_PC_CR286Publication of Zero MIUNs when no PQ Pairs available

SEM R2.2.0 – Apr – Scope to Date The following Modification Proposal is approved for the SEM R2.2.0 release: The release cut-off date for the April 2013 release to the Central Market Systems is : Friday, June 22 nd, 2012 All approved Modifications Proposals will be allocated to this release (subject to available capacity). Mod RefCR RefDescription Mod_17_11SEM_PC_CR281Addition of a D+3 DI report