1. MARKET SYSTEM RELEASE UPDATE Modifications Committee Meeting 25 September 2012

2. Two releases have been scheduled to address a number of defects that were identified in the run-up to and subsequent to IDT go-live. SEM R2.0.1 – deployed successfully on Sep. 18 th SEM R2.0.2 – awaiting delivery from vendors SEM R2.0.2 is required due to the identification of a “Long Day” defect after delivery of SEM R2.0.1. It needs to be addressed independently as the next bi- annual release (Nov.) is after the Long Day transition. SEM R2.0.1 & SEM R2.0.2 – IDT “Wash-Up”

3. The Approved scope for SEM R2.1.0 is as follows: The deployment date has been set to Friday Nov. 16 th due to SEMO and vendor resourcing constraints - only deployment date affected – all other aspects are on schedule. SEM R2.1.0 – Scope 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

4. In addition, the proposed solution to the “Extreme Ramping” Scenario identified in the MIUN Calculation software will be implemented as part of this release. SEMO has issued various communications on this item and delivered a related presentation to the Market Operator User Group on Sep 18 th. SEMO will be submitting a Modification Proposal in respect of the proposed solution, amending the MIUN Calculator rules as set out in Agreed Procedure 2. SEM R2.1.0 – Scope – MIUNs Firmness

5. SEM R2.2.0 – Apr. 2013 – Scope Regulatory approval was received on Sep. 18 th for the final scope for SEM R2.2.0. The approved scope is as follows: Mod RefCR RefDescription Mod_17_11SEM_PC_CR281Addition of a D+3 DI report Mod_03_12SEM_PC_CR290Alignment of T&SC with Revised VAT arrangements SDSSEM_PC_CR193TLAF Publishing in the MPI SDSSEM_PC_CR262Unit Under Test Submission Screen SDSSEM_PC_CR289Internal Submission Gates Option 1 SDSSEMPC_CR295MA System Summary IC Flows

6. SEM R2.3.0 – Oct. 2013 – Release Cut-Off Date The release cut-off date for the October 2013 release to the Central Market Systems is: Friday February 22 nd, 2013. All approved Modifications Proposals will be allocated to this release (subject to available capacity).