MARI (Manually Activated Reserves Initiative)

MARI is the European platform for the cross-border exchange of mFRR balancing energy under Article 20 of EBGL Regulation (EU) 2017/2195. Connected TSOs submit standard mFRR bids into a common merit order list; every 15-minute market time unit the platform clears the cheapest combination of bids needed to meet aggregate mFRR demand, at a marginal price per direction. Elering joined MARI on 9 October 2024.

MARI (Manually Activated Reserves Initiative) is the European platform for the cross-border exchange of mFRR balancing energy. It is implemented under Article 20 of the Electricity Balancing Guideline (Commission Regulation (EU) 2017/2195) and operated by ENTSO-E member TSOs.

How it works

Each connected TSO submits its standard mFRR bids into a Common Merit Order List (CMOL). Every 15-minute Market Time Unit, MARI runs an activation optimisation that respects available cross-zonal capacity, selects the cheapest combination of bids needed to meet aggregate mFRR demand, and clears at a marginal price per direction. Direct activation (intra-MTU) handles fast-response situations.

Estonia and the Baltic TSOs

Elering joined MARI on 9 October 2024, alongside AST (Latvia, 4 October) and Litgrid (Lithuania, 8 October), ahead of the 9 February 2025 Continental synchronisation. Eesti Energia was the first Estonian BSP to forward bids from day one. Since accession, Baltic mFRR scarcity events have repeatedly cleared at the platform price cap of ±10 000 €/MWh.

Energy not capacity

MARI is a balancing-energy platform — the activation marketplace, not the procurement market. mFRR balancing capacity is procured separately, in the Baltics through joint mFRR auctions run by Elering, AST and Litgrid. The companion PICASSO platform plays the same role for aFRR energy.

Live data

Estonia mFRR clearing prices coming out of the MARI cross-border merit order, refreshed hourly: mFRR clearing price chart.

Sources

ENTSO-E: MARI · EBGL Article 20 · Elering: Balancing service · Eesti Energia: MARI go-live

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What is MARI?

MARI (Manually Activated Reserves Initiative) is the EU-wide platform for the cross-border exchange of mFRR balancing energy. It is implemented under Article 20 of the Electricity Balancing Guideline (Reg 2017/2195) and operated by ENTSO-E member TSOs. MARI clears every 15 minutes, picking the cheapest combination of mFRR bids across connected TSOs to meet aggregate balancing demand at a single marginal price per direction.

When did Estonia join MARI?

How does MARI clearing work?

Every 15-minute Market Time Unit, MARI runs an activation optimisation that respects available cross-zonal capacity, selects the cheapest combination of bids needed to meet aggregate mFRR demand, and clears at a marginal price per direction. Direct Activation handles fast-response situations within the MTU. Bids that win activation receive the cross-border marginal price, not their bid price (pay-as-cleared).

What's the difference between MARI and PICASSO?

MARI is the European platform for mFRR balancing energy (manual, 12.5-minute response); PICASSO is the European platform for aFRR balancing energy (automatic, 5-minute response). Both are operated by ENTSO-E member TSOs under EBGL but they handle different reserve products. Most TSOs are connected to both — Estonia joined MARI in October 2024 and PICASSO in April 2025.

Where can I see MARI clearing prices for Estonia?

Volton publishes the live Estonian mFRR clearing price coming out of MARI cross-border merit order at /data/mfrr-clearing-price, refreshed every 15 minutes. The Baltic Transparency Dashboard publishes the same data alongside cross-border marginal prices, activated volumes and the netted cross-border flows from each Baltic country.