Replacement Reserve (RR)

Replacement Reserve is a harmonised service across participating European TSOs for the provision of both an increase and decrease of active power.


In the table below, we set out the mechanism by which market participants can prequalify for TERRE.

BM Unit Type

Route to prequalify

Primary/Additional BMU

Contact [email protected]

Secondary BMU

To prequalify a Secondary BM unit for the BM and TERRE for the first time, via the links in the box titled Prequalification Portal under the Overview tab.

For existing Secondary BM units, contact [email protected]

The time frame for Prequalification is set out in the System Operator Guidelines, while we have established the specific steps that need to be completed to successfully prequalify.

Within eight (8) weeks of an application, NGESO shall confirm that the application is complete (from the perspective of the information provided).

If the application is incomplete, the applicant shall provide the missing information within four (4) weeks of a request from NGESO or it will be presumed that the application has been withdrawn.

Within three (3) months of NGESO confirming that all information has been provided, it shall confirm if the applicant and its units are prequalfied for TERRE. This will be on the basis that all necessary systems (EDL/EDT, Operational Metering and Elexon Registration) have been completed.

Where a unit that has previously prequalified for the BM, wants to prequalify for TERRE, then it will only need to provide information as the existing systems will already be in place.

Guidance Documents

This below document contains guidance on how to use the prequalification portal for Replacement Reserve and Wider Access.

Overtime, an FAQ document will be shared and regularly updated to provide further clarification to participants on the prequalification process.