Electricity cannot be stored in the transmission grid, so the amount of electricity fed in must always be the same as the amount of electricity fed out. This means the production and consumption of energy must always be balanced. This equilibrium ensures the secure and stable operation of the grid at a constant frequency of 50 Hertz. The Swiss transmission grid is not the only one that is operated at a frequency of 50 Hertz; the same is true for the entire European interconnected grid. Swissgrid works together with the other transmission system operators to ensure that the frequency in this interconnected grid can be maintained at all times.

If unforeseen fluctuations arise, the operators in the grid control rooms use control energy, a reserve that power plants keep available for Swissgrid and that can be retrieved as required. The power plants either increase or decrease their power to compensate for any missing or excess electrical energy.