Up- / Down-regulation
Up-regulation (ülesreguleerimine) is the TSO's purchase of additional energy from the system when consumption exceeds forecast or generation falls below it. Down-regulation (allareguleerimine) is the opposite — the TSO sells additional energy out when consumption is lower or generation higher than forecast. The asymmetric spread between UP and DOWN prices is the structural reason mFRR has been the highest-yield reserve product for Estonian batteries since 2024.
Up-regulation (ülesreguleerimine) is the TSO's purchase of additional energy from the system, triggered when actual consumption exceeds forecast or generation falls below forecast. Down-regulation (allareguleerimine) is the opposite — TSO sells additional energy out of the system, when consumption is lower than forecast or generation higher. Both are defined verbatim in Elering's electricity-market handbook.
How activations route to BSPs
When up-regulation is needed, the TSO dispatches aFRR or mFRR up-bids in merit order: cheapest first, until the imbalance is covered. The activated BSPs ramp generation up or load down. Down-regulation reverses the sign — BSPs ramp generation down or load up. A battery sitting at 50% state of charge can in principle bid both directions in the same hour.
Settlement asymmetry
The activated BSPs receive a regulation-direction-specific price (UP or DOWN). Estonian operators see typical asymmetry: UP prices (when the system is short) often clear well above the spot price; DOWN prices (when the system is long) often clear near or below zero. The asymmetric spread is the structural reason mFRR has been the highest-yield reserve product for Estonian batteries since 2024.