What is mFRR (manual Frequency Restoration Reserve / R3)
mFRR is the manual Frequency Restoration Reserve that helps to stabilize the frequency of the electricity grid. In most countries the TSO (Transmission System Operator) is responsible for its procurement and activation. The mFRR (also R3 or tertiary reserve) helps to restore the required grid frequency of 50 Hz (or in some countries of 60 Hz). This tertiary control reserve intervenes when there are longer lasting deviations in the power grid that cannot be resolved solely by the other upstream balancing services (FCR or aFRR).
mFRR must be, according to the guidelines proposed by the European Network of Transmission System Operators of TSO in Europe (ENTSO-E), fully deployable after 12.5 minutes and has a minimum duration period of 5 minutes. Different auctions determine which Balancing Service Provider (BSP) holds back capacities and/or delivers the reserve in case of imbalances for each quarter hour.