MARKET SYSTEM RELEASE UPDATE Modifications Committee Meeting 27 March 2012

SEMO is responsible for implementing changes to the Central Market System (CMS): Modification Proposals approved by the Regulatory Authorities. Non-Code related Change Requests recommended by the SEM Design Service (SDS) and approved by the Regulatory Authorities. SEMO implements these changes by: Translating the agreed business requirements to detailed systems requirements/design. Baselining the design for delivery by our vendors. Testing software internally (system integration and regression) to ensure that baselined requirements have been met. Communicating as required with stakeholders. Where Participant interface changes occur, conducting Market Trial to demonstrate that the CMS and Participant interfaces will operate in accordance with the Code. Managing Cutover / Deployment. Implementation of Central Market Systems changes

Scope for SEM R2.0.0 is as follows: SEM_PC_CR284 added to scope on 2 December Change to the vendor design to ensure alignment of Intra-Day Trading solution with Mod_18_10_v2. SEM_PC_CR287 added to scope on 12 December Minor change included to align with the Code and to ensure Participants could effectively manage Credit Cover under Intra-Day Trading. SEM R2.0.0 – Intra-Day Trading - Scope Change RequestMod RefDescription SEM_PC_CR22218_10_v2Intra-Day Trading SEM_PC_CR244SO Security (Option 1) SEM_PC_CR25643_10Variable Price Taker Generator Units and Firm Access SEM_PC_CR28418_10_v2Data 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. SEM R2.0.0 – Intra-Day Trading – Project schedule ActivityScheduleStatus Detailed Requirements1 Dec 2010 – 30 Apr 2011Complete Vendor Detailed Design1 May 2011 – 29 Jul 2011Complete Design Deliverables Issued to Participants (MPUD etc.) 29 Aug 2011Complete Participant Engagement Plan published9 Sep 2011Complete Participant Systems Design Workshops28 Sep, 5 Oct 2011Complete Vendor Implementation20 Jun 2011 – 11 Nov 2011Complete Factory Testing14 Nov – 23 Dec 2011Complete System Integration Testing3 Jan 2012 – 27 Apr 2012In Progress Market Trial30 Apr 2012 – 6 Jul 2012Preparation in Progress Target Deployment Date20 Jul 2012On Track

The Approved scope for SEM R2.1.0 is as follows: SEM R2.1.0 – October 2012 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 – April 2013 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 System is : Friday, 22 June 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