What is Frequency Containment Reserve (FCR)
To ensure the required grid frequency of 50 or 60 Hz (depending on the concerning country) the Transmission System Operators (TSO) of each country need instruments to maintain this reference value. These instruments are the balancing services. Balancing services are reactive short-term means to level out frequency deviations in the power grid. When frequency deviations occur, e.g. in consequence of a power plant outage, the Frequency Containment Reserve (FCR) intervenes automatically within seconds in the entire synchronous area to restore the balance between supply and demand. The FCR, also known as primary control reserve, is the first response to frequency disturbances. If the deviation persists, the Automatic Frequency Restoration Reserves (aFRR) subsequently replace the primary control reserve.