P344 and Wider Access & TERRE Release update

ELEXON is in the final stages of implementing its P344 Wider Access Release commitments, currently scheduled to be deployed on 11 December 2019. Implementing P344 will allow ELEXON to open up the market for independent aggregators to enter the Balancing and Settlement Code (BSC) as Virtual Lead Parties (VLPs). 

Through the Wider Access Release, BSC parties will have access to the new systems and processes required to start trading in the BSC. 

Industry testing

ELEXON has now completed industry testing with a group of VLPs to ensure all systems and processes are fully functioning ahead of the planned deployment on Wednesday 11 December 2019. We’d like to thank all participants for taking part in this process and bringing it to a successful close. 

Next steps

This week we will continue to work with National Grid ESO, and will agree the exact P344 implementation date and time* on Monday 9 December.

IT systems outage will take place from 18:57 (GMT) on Tuesday 10 December to 00:45 (GMT) on Wednesday 11 December 2019. to accommodate the deployment of the Wider Access Release. See the complete details about the IT systems outage. 

More information on the detail of the Wider Access change can be found in ELEXON’s Impact on New & Existing BSC Parties. The document provides details about the impact of Wider Access for new and existing Parties.

We would highly recommend that as a minimum, Parties should review the ‘Impact on All BSC Parties’ section on page 4, which highlights impacts that affect all Parties, including the changes to the format of your Settlement reports (SAA-I014) and to some messages from our BM Reporting System.


On 28 November 2019 Ofgem granted National Grid ESO’s request for a derogation from participation in Project TERRE. 

Read full details and the ELEXON response on the Project TERRE derogation decision.

More information

Find out more about the Wider Access and TERRE Release.

Get all the information and latest updates about Wider Access and TERRE and find out more about how ELEXON has opened up the market entry process for independent aggregators to the Balancing and Settlement Code (BSC) as Virtual Lead Parties (VLPs) in the ‘What is Wider Access’ section.

*Our projects are coordinated with National Grid ESO and all projects require changes to live systems. Go-live dates are dependent on National Grid ESO experiencing favourable operational conditions at the time to allow them to go into the production environment. There are contingency plans in place in the event that implementation is not possible on the intended dates.


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