Swissgrid is having to intervene more and more frequently to ensure that parts of the transmission grid are not overloaded. This is mainly due to the restructuring of the electricity system and increasing electricity flows across national borders, which are causing congestion in the grid. This makes grid operations more demanding and more expensive.
If there is a risk of overloading on a line or transformer, this is referred to as congestion. Swissgrid has to intervene in ongoing grid operations to eliminate this congestion. It may also be necessary for Swissgrid to adjust the production of power plants. A power plant on one side of the congestion is instructed to generate more electricity, whilst a power plant on the other side is told to generate less. The volume of electricity remains the same overall, but it is distributed differently geographically – so that less electricity flows via the affected grid element. This is called redispatching.
Two developments are leading to an increasing need for redispatching interventions of this kind:
- The electricity system is changing: more and more electricity is coming from renewable resources such as solar and wind power. These resources do not generate electricity evenly – which makes the flow of electricity more unpredictable and leads to high power peaks. The mostly decentralised nature of renewable energies is resulting in changes in production locations. Yet the grid was designed for traditional production at centralised locations.
- International electricity flows are rising: the Swiss transmission grid is closely linked to the European grid. Electricity is increasingly flowing across borders – leading to additional loads.
The extent of the rise can be seen from the figures: in 2018, Swissgrid had to use 170 gigawatt hours (GWh) of energy for redispatching measures; by 2024, the figure had risen to 660 GWh – almost four times as much.
International cooperation is becoming more important
Not all congestion can be resolved by measures in Switzerland alone – especially if it occurs at or near the border. In these cases, Swissgrid has to work with neighbouring transmission system operators.
For example, redispatching power is required more and more frequently in Germany – due to the high feed-in of solar and wind energy. Swiss storage power plants make an important contribution to congestion management. But Switzerland also repeatedly needs redispatching support from neighbouring countries, for instance in the summer when high production at the storage power plants in the Alps coincides with high solar power peaks.
Grid operations are becoming more complex – costs are rising
As the number of congestion incidents increases, so does the workload for Swissgrid. Swissgrid’s specialists are having to intervene more and more frequently. What is more, the necessary redispatching energy is not always available. This makes grid operations even more difficult.
The costs of these interventions are usually borne by the party responsible. For international redispatching, this means the requesting grid operator, whereas Swiss electricity consumers have to pay for national measures in Switzerland.
The key lies in expanding the grid
Close cooperation with Europe is required to ensure that the grid can continue to be operated stably and with as little congestion as possible in the future. At the same time, however, the grid also needs to be expanded and modernised. Swissgrid has a clear plan for this: the Strategic Grid. This is based on the federal government’s scenarios and shows where the grid needs to be enhanced, modernised and expanded.
The problem is that expansion is progressing slowly due to the lengthy processes. Today, it often takes 15 years between the planning and commissioning of a line. Simpler, faster processes are needed to speed up expansion. This is the only way to overcome the growing challenges in the grid.
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