Load-Frequency Control Block (LFC Block) is a part of a synchronous area or an entire synchronous area, physically demarcated by points of measurement at interconnectors to other LFC Blocks, consisting of one or more LFC Areas, operated by one or more Transmission System Operators (TSOs) fulfilling the obligations of a load-frequency control (Article 3(18) od the Commission Regulation (EU) 2017/1485 of 2 August 2017 establishing a guideline on electricity transmission system operation (System Operation Guideline - SOGL)).


The LFC Block refers technically to the balancing zone, which defines the size of the network area for which the balancing capacities are being procured (Commission Staff Working Document accompanying the document Commission Regulation of 23.11.2017 establishing a guideline on electricity balancing {SWD(2017) 383 final} p. 3). 


The LFC Block is important as this is the geographical area over which reserves (other than the fastest type) ought to be dimensioned (The EU electricity network codes, Technical report, Leonardo Meeus, Tim Schittekatte, European University Institute, Badia Fiesolana, February 2018, p. 11).


Hence, at the level of the LFC Block the following reserves are dimensioned:


- Frequency Restoration Reserve (FRR) - Article 157 of the SOGL,


- Replacement Reserve (RR) - Article 160 of the SOGL.


The determination of the LFC Blocks must be proposed by all TSOs of a synchronous area four months after the entry into force of the SOGL (art. 141(2) of the SOGL).




IMG 0744





Network Code on System Operation (SOGL), Article 3(2)(18), 157, 160









Scheduling area


Responsibility area


Bidding zone


Monitoring area








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