Frequency Control Reserve (FCR)

Frequency Control Reserve (FCR)

Frequency containment reserve, also known as frequency control reserve (FCR), is a mechanism used by transmission system operators (TSO) to keep the electricity grid stable and reliable. It is a rapid and automatic response to sudden changes in electricity supply or demand that helps stabilise the system frequency within acceptable limits. FCR acts as a safety net, ensuring that frequency deviations are swiftly corrected.

FCR, aFRR and mFRR scheme

FCR is a type of ancillary service. It acts as a primary control reserve, meaning that it is the first measure to use when the frequency of the grid deviates from its normal operating range. It is used only for initial stabilisation of the grid, then aFRR and mFRR take its place.

How Does FCR Work?

The main objective of the Frequency Containment Reserve is to restore grid frequency back to its nominal value following disturbances. This can happen for example when there is a sudden increase in demand or when a provider stops generating energy.

When a sudden deviation in frequency such as this occurs, the FCR comes into action. The reserve power is immediately injected or withdrawn from the grid to balance the mismatch between supply and demand. This then stabilises the frequency.

FCR providers, typically power plants or other large generating units, are contracted to maintain a predetermined reserve capacity. These providers are equipped with control systems that continuously monitor grid frequency. When a deviation is detected, the control system quickly adjusts the output of the reserve capacity to counteract the frequency variation. The response time of FCR is typically in the order of seconds, ensuring a swift correction.

The FCR market is often organised through a balancing mechanism, where providers bid their available reserve capacity and associated costs. Grid operators select the most competitive offers, considering factors like cost, availability, and location. These providers then commit to maintaining the agreed reserve capacity and are compensated accordingly.

What Kinds of Ancillary Services Are There? What Are the Differences?

As we mentioned before, FCR is a type of ancillary service. Just as aFRR and mFRR - these three all describe different frequency reserve services. These products vary in their activation times and the way they work to balance energy.

FCR stands for Frequency containment reserve and is also known as primary reserve. The primary reserve is used to quickly stabilise the grid in 30 seconds (automatically activated in the generator of the power plant). For instance, hydropower plants and battery generators instantly adjust the amount of electricity available in response to a frequency deviation throughout Europe. Primary reserve is used only for initial stabilisation and is augmented by secondary control as soon as possible so that FCR can be prepared for the next activation. 

aFRR stands for automatic Frequency Restoration Reserve also known as secondary reserve. The secondary reserve must be activated in either 7.5 minutes or 5 minutes depending on the country. aFRR is provided by many different device types, the main requirement is that they can be fully activated within the required time. It is possible to combine devices together, such as a battery and biogas plant to create one device that is both quick to activate and also able to be activated for a longer duration. 

mFRR stands for manual Frequency Restoration Reserve also known as tertiary reserve. Devices operating on mFRR must be activated within 15 or 12.5 minutes depending on local laws. These devices are always activated manually - based on the demand of TSOs’ dispatchers, meaning a dispatcher will alert the device operator to activate the device at the specified time.

When Is FCR Activated?

In Europe, the transmission system operators (TSOs) must maintain a frequency of 50 Hz in order to maintain balance in the grid. FCR works to quickly restore the frequency to its normal level. 

According to ENTSO-E regulations, the full activation of the frequency reserve must be accessible within 30 seconds and cover a duration of 15 minutes. When the frequency variation is outside the requirement between 49.99 Hz and 50.01 Hz, FCR providers are required to submit the volume requested by the TSO.

After 30 seconds, the aFRR gradually takes the place of the FCR.

Frequency Containment Reserve is an indispensable tool for maintaining power system stability. By swiftly responding to imbalances between electricity supply and demand, FCR helps restore grid frequency to its nominal value, preventing disruptions and ensuring stable and reliable power supply. As the energy landscape continues to evolve with increased renewable integration, the significance of Frequency Containment Reserve will only grow, enabling a more resilient and sustainable power system.

As an energy asset owner, you may be interested in finding ways to create more value from your assets. Nano Energies has expertise in ancillary services and can help you optimize the operation of your assets and increase their value. By partnering with us, you can take advantage of our advanced technology and expertise to make informed decisions about how to best manage your energy assets. If you want to learn more about how we can help you, don't hesitate to contact us for more information. We would be happy to speak with you and answer any questions you may have.

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