With the expansion of renewable energies, the number and variety of decentralised energy suppliers increasing depending on external environmental influences. A good example is the operation of a wind park, which feeds into the grid during a strong wind, but not in the case of a doldrums. The resulting, unexpected fluctuations in the power grid are therefore compensated by suppliers of controlling power.
Regular service providers can compensate for a short supply of additional energy (positive control power). On the other hand, however, excess energy can also be compensated in the power grid (negative control power).