MARKET SYSTEM RELEASE UPDATE

Modifications Committee Meeting

5 April 2011

• Regulatory Approval received on November 12th, 2010.• Defined scope includes 4 Approved Modification Proposals (see table below)

plus an additional 15 non T&SC Change Requests.• Project is on-schedule for deployment on May 6th, 2011.

SEM R1.9.0 – Deployment May 6th, 2010

Change Request ID Mod Ref Sub-System Description Raised By

SEM_PC_CR217 46_09 MA/MI Treatment of UIs for Pumped Storage Units Mods Cmte

SEM_PC_CR242 12_09 MA/MI Loss adjustment of SUC and NLC in CONP and MWP Mods Cmte

SEM_PC_CR199 34_09 STL Global Settlement Mods Cmte

SEM_PC_CR243 39_10 STL Change from 7_12 to 4_91 NDLF calculation Mods Cmte

• Release cut-off date was Friday, February 18th, 2011.

• As at the release cut-off date there were:• No outstanding Modification Proposals approved for implementation.• No new external Change Requests received by the SEM Design Service (SDS).

• One change was outstanding from the SEM R1.9.0 release (due to timeline pressures) – SEM_PC_CR172 Transfer of MIUNs from the Moyle Interconnector Trading System (MITs). 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 circa October 2011.

• This change will form the scope for SEM R1.10.0 along with fixes for any outstanding defects.

• There will be no SDS changes in the SEM R1.10.0 release.

• Regulatory Approval for scope was received on 24th March, 2011.

SEM R1.10.0 – Oct. 2011

• Mod_18_10: Intra-Day Trading was approved for implementation at the SEM Governing Committee meeting of March 2nd.

• This is a significant change, impacting many components of the Central Market Systems. Vendor effort for the delivery of Intra-Day Trading (excluding TSO changes to RCUC and hardware refresh).

SEM R2.0.0 – Intra-Day Trading

• The vendors have indicated that there is little scope for including additional changes within the Intra-Day Trading release, however SEMO is aware that ongoing change to the Market must continue to be considered.

• With this in mind the release cut-off date for the Intra-Day Trading release is Friday August 5th, 2011.

• Minor changes will be considered for inclusion in this release (Approved Modifications)

• The implications of including such changes in the Intra-Day Trading release must be carefully considered in the following context: • Impact on delivery timescales for Intra-Day Trading, taking into account:

• Vendor resource constraints;• Required hardware refresh;• SEMO resource constraints; and

• Impact on costs.

• Any change that cannot be absorbed into the Intra-Day workstream will be included within the next release where capacity is available as per the agreed process.

SEM R2.0.0 – Intra-Day Trading