In terms of quality of supply, Switzerland occupies one of the top spots in a pan-European comparison. The average outage duration per consumer and year in Switzerland was 19 minutes in 2019. Only 0.2 per cent of this can be attributed to the transmission grid. This makes the Swiss transmission grid one of the most secure and stable electricity grids in the world.
The transmission grid is a critical infrastructure. As the operator of this infrastructure, Swissgrid has various built in resilience factors that make a significant contribution to the high security of supply. Specifically, this means the transmission grid must continue to operate without disruption despite any shocks that may occur. For one thing, this means preventing damage from occurring and, if it does occur, maintaining operation and restoring it to a sustainable condition.
In a three-part blog series, we explain how Swissgrid creates resilience in the transmission grid in the areas of installations, operation and supply as well as in relation to the human factor. In the second part of this series, we turn our attention to the area of supply.
This makes the Swiss transmission grid one of the most secure and stable electricity grids in the world.
Swissgrid has an important role
The secure supply of electrical energy requires not only a reliable grid infrastructure, but also a sufficiently high level of production. The best transmission grid is useless if electricity generation cannot meet demand. These kinds of situations are very rare, but they are quite possible due to a chain of several unfortunate circumstances. For example, 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. The dry summer and autumn caused the rivers to carry significantly less water than the long-term average. This reduced electricity generation from run-of-river power. The level of the reservoirs was also found to be below average based on a long-term comparison. The nuclear power plants Beznau 1 and 2 were also both out of service.
The lack of constant energy from hydropower and nuclear power had to be compensated for with other types of generation, particularly from storage power plants and imports. Since the capacity for the transformation from 380 kV to 220 kV is limited, imports were only usable to a limited extent to compensate for the lack of constant energy.
While Swissgrid is not responsible for Switzerland's supply of energy as the transmission system operator it plays an important role in solving such problems because its energy demand for Ancillary Services and the availability of import capacity are used as a dimensioning parameter for the planning of electricity supply companies. With the Electricity Supply Act, the legislator entrusted the Federal Electricity Commission Elcom with the task of monitoring and supervising the electricity markets, with a view to ensuring secure and affordable supply in all parts of the country. If there is any indication of a significant threat to domestic security of supply in the medium or long term, Swissgrid's task is to propose appropriate measures to the Federal Council to maintain a secure supply of electricity.
Resilience factors: import capacity and European interconnected grid
While Switzerland normally exports electricity in summer, it tends to rely on imports in winter. After the strained situation in the winter of 2015/2016, Swissgrid reacted quickly and increased its transformation capacity. In recent years, corresponding 380/220-kV transformers have been procured and some have already been installed.
The Swiss transmission grid is part of the European interconnected grid and is very closely connected to neighbouring countries via 41 international interconnection lines. This close meshing is also a key resilience factor. The exchange of electricity makes it possible to overcome electricity bottlenecks and avoid overloads. This international cooperation allows power plant outages or overproduction to be compensated for.
Since 2014, the EU has made a framework agreement, the scope of which would have gone far beyond the electricity agreement, a mandatory requirement for concluding an electricity agreement. On 26 May 2021, the Federal Council communicated its decision not to sign the institutional agreement with the EU. However, it still wants to continue on the bilateral path. This means that the electricity agreement is on hold for the time being.
Without an electricity agreement, the full integration of Switzerland (grid and trading) into the European single electricity market is put at risk and its participation and right of co-determination in relevant European bodies, e.g. ENTSO-E is jeopardised. In addition, the lack of regulatory integration of the Swiss Electricity Market in Europe has a negative impact on Switzerland's grid stability. The EU's ability to import (and willingness to export) is also put at risk.
Swissgrid is assuming that the intensity of the challenges for grid security is likely to increase notably up to 2025 due to the further optimisation of the flow-based market coupling in the EU. Both now and in the future, Swissgrid will exhaust all means and possibilities available to it to guarantee stable grid operations. Resolving these challenges requires support from policy-makers.
The exchange of electricity makes it possible to overcome electricity bottlenecks and avoid overloads.