Wider Access and TERRE

This page gives an overview of Wider Access, which will removal the barriers currently facing independent aggregators wanting to participate in the balancing mechanism, and TERRE (Trans European Replacement Reserve Exchange) which is a European project to implement a new Replacement Reserve (RR) balancing product.

This page will detail the latest updates regarding Wider Access and TERRE.

Latest updates

TERRE derogation request

National Grid acting as National Electricity Transmission System Operator (NETSO) has requested a derogation from Ofgem to delay GB participation in TERRE until 2020 (keeping GB aligned with France).

The request is still pending.
3 October 2019

Wider Access and TERRE release

Wider Access will be deployed in mid-December ahead of TERRE. Exact timelines will be confirmed and published by the end of the month.
4 November 2019


The impact BREXIT will have on Wider Access and TERRE will depend on if Great Britain leaves the EU with a deal or not.

If No-deal occurs – In the event of a no-deal Brexit, GM market participants will not be able to participate in TERRE.

However, the expectation is that Parties will be able to participate at some point in the future once a post no-deal framework is agreed.

If a Deal is agreed – TERRE development will continue. The original Withdrawal Agreement has no impact on the electricity industry’s participation in the EU and nothing has been announced to suggest this would change if a deal is agreed next week.

Completing TERRE development will mean that we are ready to go as soon as GB market members are allowed to participate.
10 October 2019

Industry testing

Our recently published Industry Testing Strategy for Wider Access will focus and prioritise our plans for testing Wider Access before TERRE testing.

Wider Access testing will take place in late November.

GB testing with TERRE was due to happen this autumn; however, this wil now take place next year.
4 November 2019

Wider Access Impact Assessment

ELEXON’s Wider Access Impact Assessment sets out the technical changes parties will need to prepare for Wider Access in December 2019. 
4 November 2019


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