The operation of the transmission grid is based on long-term planning. The operators in the grid control room in Aarau use a grid model to prepare an initial forecast of the expected grid situation over a year in advance. This planning considers events such as renovations and repairs of power plants or lines; decommissioning grid elements has an impact on transport capacities.
The planning of the grid operation is refined on an ongoing basis: the expected grid situation is constantly recalculated one year, one month, one week, two days and one day before real-time operation. For instance, the operators calculate the cross-border capacity that can be made available for electricity trade two days before live operation. One day before, the operators update their planning based on the schedules provided by power plants and electricity traders, which contain both domestic and international electricity trading transactions. The grid control room works together with the grid operators in neighbouring countries to check whether the grid and the international interconnection lines can transmit the produced and traded volume of energy, where congestion exists, and the action that needs to be taken.
Operational planning aims to keep the grid stable and effective around the clock. As part of the planning process, Swissgrid consults affected parties, such as power plant operators and neighbouring transmission system operators, well in advance so it can provide as much capacity as possible on the transmission grid without placing grid security at risk.