INTRA-DAY TRADING Modification Development 5 April 2011

The introduction of intra-day trading in the SEM represents major changes in the market design – detailed in the High Level Design. As a result, there will be major changes to the Trading and Settlement Code (“Code”), including: Bidding to multiple Gate Windows (EA1, EA2 and WD1) for the relevant Trading Day. Restriction of Interconnector Unit bidding in the EA1 Gate Window to Capacity Holders. Reallocation of unused Interconnector Capacity to any Interconnector Unit (with no requirement to be a Capacity Holder) in EA2 and WD1 MSP Software Runs. Different lengths of Trading Window for each Ex-Ante MSP Software Run: EA1: entire Trading Day EA2: entire Trading Day WD1: second portion of the Trading Day Fixing of Interconnector Unit capacity allocations from EA1 MSP Software Run (MIUNs) in the EA2 and WD1 MSP Software Runs. Limiting Interconnector Unit Nominations in EA2 and WD1 Changes to Credit Cover arrangements in respect of Interconnector Units. Introduction

As per Modifications Committee and the RA decisions, SEMO is developing the legal text of the Intra-Day Trading Modification. This Modification will be considered in “Functional Groups” via a series of Working Groups, before being presented as a single (large) Modification to the Modifications Committee in late 2011 Intra-Day Trading Modification

Since approval of the High Level Design, SEMO has been progressing Detailed Design with its vendors, which is being finalised. The Terms of Reference of the Working Group is to produce a Modification which aligns with the RA-approved High Level Design by: Reviewing SEMO’s draft rule changes, ensuring that the resulting Modification Proposal aligns with the agreed High Level Design. Identifying and addressing areas of change to the Code not identified by the drafting Discuss and address drafting issues raised by SEMO. Recommend to the Modifications Committee whether drafting aligns with the High Level Design. Review the content of the Plain English Documents (PED) and provide comments to SEMO. Report to each Modifications Committee meeting on the progress of the development of the Modification Proposal drafting. Confirm to the Modifications Committee once the Modification Proposal is fully drafted, the alignment with the High level Design. Design Status Context for the Working Group

Functional Grouping Functional Group Name Contents 1) Registration and Submission  Registration of Interconnector Units  Participation Notices / Participation Fees  Definition of Gate Windows and Trading Windows  Commercial Offer Data submission  Technical Offer Data Submission 2) Data Transactions and MSP Software  TSO/IA Data Transactions  Publication and Reporting (not credit)  MSP Software operation and calculation 3) Settlement and Credit Management  Credit publication and reporting  Calculation of Required Credit Cover  Calculation of Available Credit Cover  Available Credit Cover sufficiency checks  Calculation of Modified PQ Pairs for Interconnector Units  Interconnector Unit settlement calculations Single Modification presented to Modifications Committee

Meeting Timelines WG #1: 10 May (Belfast) Functional Group 1: Registration and Submission WG #2: 29 June (Dublin) Functional Group 3: Credit and Settlement WG #4: 10 Nov (Dublin) ALL Functional Groups WG #3: 06 Sep (Belfast) Functional Group 2: Transactions & MSP Software SEMO will provide the content for the Working Groups, as per the defined Functional Groups. SEMO intends to provide the following, two weeks prior to the relevant Working Group meeting: Plain English Document (PED) for the relevant Functional Group(s). Legal Drafting (Code, APs, Appendices) for IDT and changes identified by SEMO to address errors, typos etc identified during its review of the Code. This will be changed marked against v8.0 of the Code and will not be put into the standard Modification Proposal form (to save time).

Maintaining alignment with the High Level Design In developing the legal drafting and to support the deliver of the objectives of the Working Group, SEMO is maintaining a mapping of: Provisions of the High Level Design (as approved) Individual Requirements from its vendor User Requirements Specifications (URS) Code clauses/AP sections High Level Design SEMO Mapping T&SC Legal Drafting User Requirements (Detailed Design)