Winter 2022/2023

Swissgrid shares the Confederation’s assessment that there are uncertainties with regard to the secure supply of electricity in the winter of 2022/2023.

Responsibility for the security of supply in Switzerland is shared by various players. As the national grid company, Swissgrid is responsible for ensuring the non-discriminatory, reliable and efficient operation of the transmission grid.

The Federal Council has enacted various measures to increase the security of supply in the short term and has assigned new roles to Swissgrid.

Swissgrid is working closely with partners in Switzerland and abroad and doing everything it can to contribute to Switzerland’s secure and reliable supply of electricity. Ensuring secure grid operation is an absolute priority for Swissgrid. At the beginning of July 2022, Swissgrid set up an internal task force that continuously monitors and analyses the current situation and plans possible measures on the basis of various scenarios.

Hydropower reserve

The Federal Council has decided to establish a hydropower reserve for the winter of 2022/2023. The measure contained in the Federal Act on a Secure Electricity Supply from Renewable Energy Sources (consolidation legislation) has been brought forward by ordinance. The Federal Council will bring the hydropower reserve into force on 1 October 2022. The auction will take place at the end of October 2022.

In exchange for a fee, storage power plants will retain a certain amount of energy, the hydropower reserve, that can then be requested when needed. This reserve is intended to bridge a period of a few weeks towards the end of winter when there are fewer import possibilities and lower availability of domestic production. The Swiss Federal Electricity Commission ElCom expects a magnitude of 500 GWh plus or minus 166 GWh. It reserves the right to adjust these benchmarks at short notice. The hydropower reserve is to remain in place from 1 December 2022 until 15 May 2023.

In exchange for a fee, storage power plants will retain a certain amount of energy, the hydropower reserve.
In exchange for a fee, storage power plants will retain a certain amount of energy, the hydropower reserve.

The Federal Council has transferred the operational management of the hydropower reserve to Swissgrid by ordinance. Consequently, Swissgrid is taking on a new role that goes beyond its previous legal mandate. In specific terms, Swissgrid is providing the IT systems for handling the auction and the requests. Swissgrid is also entrusted with defining and organising training for all processes, conducting the auctions and overseeing the accounting. This requires close cooperation with the industry and new contracts.

The reserve will be used when the supply on the market on the day before delivery can no longer cover demand, i.e. when the market does not close. The market player whose demand cannot be met reports its requirements to Swissgrid. Swissgrid then requests the necessary reserve power from the reserve providers.

Against the backdrop of the current geopolitical situation, the lack of an electricity agreement with the EU and the slow approval procedures for the construction of production plants and grid infrastructure, the hydropower reserve is a comprehensible and feasible measure to ensure the security of supply.

In the medium and long term, further measures are needed to effectively counteract shortages of electricity. Swissgrid has drawn up appropriate proposals with the authorities and the industry. They include building additional domestic production capacity, accelerating procedures for the necessary expansion of production plants and grid infrastructure, and negotiating an electricity agreement with the EU.

Voltage step-ups on certain lines

In an emergency, Swissgrid should be allowed to increase the transfer capacity of the extra-high-voltage grid. This will enable Swissgrid to import more electricity from the north if necessary. Another aim is for existing congestion to be provisionally eliminated. On 17 August 2022, the Federal Council provided information on the option of a temporary voltage step-up on the Bickigen – Chippis and Bassecourt – Mühleberg extra-high-voltage lines. These two lines could then be operated at 380 kV instead of 220 kV. The measure is only planned for the period between January and April 2023. In addition, test operation of the Bickigen – Chippis line is scheduled for December 2022. This measure will increase import capacity from the north and relieve congestion on the Swiss transmission grid.

From a technical point of view, Swissgrid is preparing to periodically operate the Bickigen – Chippis line at 380 kV in the event of a critical supply situation. The permanent voltage conversion to 380 kV requires line modifications, which have been planned and are currently in the approval process.

In autumn 2021, Swissgrid already temporarily operated the Bassecourt – Mühleberg line and the coupling transformer in Mühleberg at a voltage of 380 kV for test purposes. This means that from a technical point of view, Swissgrid is ready to periodically operate the Bassecourt – Mühleberg line at 380 kV in the event of a critical supply situation. The permanent voltage conversion to 380 kV requires line modifications, which will take place from September 2022.

Grid connection of the reserve power plant

Every unused kilowatt hour counts. However, it is not only important to save electricity, but also to increase generation capacity. This is the conclusion of a report that Swissgrid prepared in association with the industry and that was presented to the administration and politicians at the beginning of the year. Swissgrid therefore welcomes the Confederation’s efforts to bring a strategic reserve onto the grid in the form of a back-up power plant.

However, a power plant must also be able to transport the energy it produces. This requires a connection to the grid. Swissgrid is building the connection between the reserve power plant and the transmission grid. Firstly, this requires the corresponding installations such as switchgear and lines. Secondly, this type of project is subject to an approval procedure. The creation of a grid connection usually takes several years. Implementing such a project in just a few months is therefore an enormous challenge. It involves uncertainties such as the availability of the necessary infrastructure components and the duration of any procedures. Swissgrid will do everything it can to connect the reserve power plant to the transmission grid on time.

Control energy for secure grid operation

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 guarantees the secure and stable operation of the grid at a constant frequency of 50 hertz. 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. Even if electricity becomes scarce in the winter of 2022/2023, Swissgrid must be able to provide sufficient control power. For this reason, procurements were made at an early stage to prepare for the winter.

The employees in the two control rooms in Aarau and Prilly monitor the entire Swiss transmission grid around the clock.

Networking with Europe

The Swiss transmission grid is part of the European interconnected grid and is connected to neighbouring countries via 41 cross-border lines. The close meshing of the electricity system and cooperation with European partners to date make a significant contribution to Switzerland’s security of supply. Close cooperation with partners in Europe is of the utmost importance for system security in Switzerland and in neighbouring European countries with regard to the winter of 2022/2023 as well. Electricity self-sufficiency would not mitigate the risk of a power shortage.

If Switzerland were to operate as an island, the entire reserve for a power plant failure in Switzerland would have to be available within Switzerland itself. It would have to be possible to compensate outages of 400 MW (Bieudron hydropower plant) to 1,000 MW (Leibstadt nuclear power plant) at any time. With a grid load of 10 GW in winter and 5 GW in summer, 10 to 20 percent of power would be lost with the outage of Leibstadt. This would have a massive impact on frequency. The drop would be striking and would cause a grid disturbance. This would lead to a partial to complete power system failure.

An island solution would jeopardise both secure grid operation and the security of supply. The legislator took the importance of interconnection with Europe into account in the Electricity Supply Act. Cooperating with the European transmission system operators and ensuring sufficient international interconnection of the Swiss transmission grid represent an explicit legal mandate for Swissgrid (Art. 20, Para. 2, lit. f StromVG).

Close cooperation with European partners requires a political or intergovernmental solution. This is the only way to establish a stable framework for secure cooperation with the EU in the long term, and hence for a high level of security of supply in Switzerland.

Close cooperation with European partners requires a political or intergovernmental solution.

Lessons learned from the winters of 2015/2016 and 2016/2017

In the autumn of 2015, it became apparent that the energy and grid situation for the winter of 2015/2016 would be strained. Energy reserves in Switzerland were scarce at that point in time due to a series of specific circumstances.

In the «Strategic Grid 2025», Swissgrid planned the grid that Switzerland will need until the reference year 2025, taking into account the Energy Strategy 2050. It makes provision for additional transformers in Mühleberg, Beznau, Chippis, Mörel and Romanel. The urgency of the rapid implementation of the associated construction projects was confirmed by the situation in the winter of 2015/2016. Swissgrid has installed additional transformers in Mühleberg, Beznau, Chippis and Romanel in recent years. However, some of them cannot yet be used as intended due to slow-moving grid projects, as transformation is only possible when 220 kV and 380 kV voltage levels meet in the substations. Accelerating the approval procedures for the construction of new lines is therefore an important concern for Swissgrid.


Planning for winter - Winter challenge.

Every kilowatt hour saved counts. Read more about the Confederation’s savings campaign:


Federal Office for National Economic Supply



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