Reserve costs included in balance service

The transmission system operator’s reserve costs account for the highest cost item in balance service. Here, reserves refer to those reserves which the TSO needs to maintain the frequency and system security of the nation-wide transmission grid. 

The costs of the various types of reserves are allocated, using the matching principle, both to balance service and to other TSO services – primarily grid service – so that the costs of frequency-controlled normal operation reserve belong to balance service, and the disturbance reserves (frequency-controlled disturbance reserve and fast disturbance reserve) belong both to balance service and other services. The principle of dividing the costs of disturbance reserves is the same for both reserves.