Manually Activated Reserves Initiative

Manually Activated Reserves Initiative (MARI) is the European implementation project for the creation, future development, and operation of the European mFRR platform.

Project Introduction

The Electricity Balancing guideline (hereinafter the ‘EB Regulation‘), approved by the Electricity Cross-Border Committee on 16 March 2017, defines tasks and a timeline for the implementation of a European platform for the exchange of balancing energy from frequency restoration reserves with manual activation (mFRR).

Given the importance of an efficient balancing mechanism for an integrated electricity market, back in 2017, 19 European TSOs initially decided to work on the design of an mFRR platform in order to address pending issues and questions connected with the establishment of such a platform as soon as possible. These TSOs decided to set a project, officially named MARI (Manually Activated Reserves Initiative), and worked on the technical solution, which does not only reflect the views of the founding parties but could also be acceptable for potential new parties joining the initiative. The project was designated as the European implementation project for the mFRR platform by all TSOs. Since then, several TSOs joined MARI.

On 24 July 2019, all regulatory authorities referred the TSOs’ mFRR IF proposal to ACER. On 24 January 2020, ACER adopted a Decision and set the deadline for the implementation of the mFRR platform, which shall fulfil all requirements defined in the mFRR IF by 30 months following the decision. On 5 October 2022 the platform has been brought successfully into operation with accession of the four German TSOs and ČEPS. On 20 June 2023 APG accessed. Further TSOs are expected to access the platform in the course of 2024.


MARI implementation project (as of February 2024)
MARI implementation project (as of February 2024)

The parties involved are:

  • Member TSOs: 50Hertz Transmission, ADMIE, Amprion, APG, AST, ČEPS, Creos, Elering, ELES, ELIA, Energinet, ESO, Fingrid, HOPS, Litgrid, MAVIR, PSE, REE, REN, RTE, SEPS, Statnett, Svenska Kraftnät, Swissgrid, TenneT DE, TenneT NL, Terna, Transelectrica, and TransnetBW.
  • Observers: EirGrid, EMS, MEPSO, SONI, ENTSO-E.

Key Performance Indicators of Implementation and Operation of the mFRR-Platform

According to the Article 13.1 of the Annex I to the ACER Decision on the Implementation framework for mFRR Platform, all member TSOs shall monitor, evaluate and report on the key performance indicators of implementation and operation of the mFRR-Platform at least on a yearly basis. The common report shall be published by ENTSO-E on its website and reported to regulatory authorities.

Stakeholder Workshops


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