Chamoson-Chippis: Important section of the planned electricity highway in Valais in operation

The Grande Dixence dam in Valais is the highest dam in Switzerland, and the reservoir holds 400 million cubic meters of water. With the Nant de Drance pumped storage power plant, one of the most powerful pumped storage power plants in the Valais went into operation at the beginning of July 2022. And on November 10, Swissgrid officially inaugurated the new power line between Chamoson and Chippis in the Valais

Spanning 30 km, the new power line between Chamoson and Chippis runs along the slopes of the left bank of the Rhone River. The new line carries four voltages on the same pylon. 380 kV, 220 kV, 65 kV between Chamoson and Aproz and 132 kV to supply the SBB between Chamoson and St. Léonard. Thanks to the construction of the new line, almost 90 km of lines and 322 pylons can be dismantled in the Rhône plain. But the main reason for the construction of this line was another. Which one? And why is the line of great importance for the Swiss electricity supply?

Energeiaplus asks Marie-Claude Debons from Swissgrid. She is responsible for the communication of this grid project.

Energeiaplus: Why is the new overhead line between Chamoson and Chippis necessary? Or put another way: Why were the old lines no longer sufficient?

Marie-Claude Debons: The new extra-high voltage line between Chamoson and Chippis removes a bottleneck in the Swiss transmission network. With two new 380-kilovolt and one 220-kilovolt power lines, it increases the transmission capacity for electricity generated by the Lower Valais hydropower plants. This has increased in particular due to the commissioning of the Nant de Drance pumped storage power plant. With the new extra-high voltage line, the energy can now be transported to the centers of consumption. The line plays a correspondingly important role for the country's security of supply.

The overhead line therefore eliminates a bottleneck in the Lower Valais. What about the lines leading away from there?

Valais is the canton that produces the most energy from hydropower. Connecting the transmission lines in Valais to the 380 kV grid is essential for transporting this Valais production from hydropower.

That is why, in addition to the Chamoson - Chippis grid construction project, several other projects must be completed. These are the Bickigen - Chippis, Chippis - Mörel, Mörel - Ulrichen and Ulrichen - Innertkirchen grid projects. These projects are part of the "Strategic Grid 2025", which includes the necessary projects for the modernization of the transmission grid to meet demand

One of these planned extra-high voltage lines plays a special role: the overhead line between Bickigen near Burgdorf (BE) and Chippis (VS) (Gemmi line). The voltage of this line is to be increased from 220 kV to 380 kV. Swissgrid submitted an application for the voltage increase in July 2015. The Swiss Federal Office of Energy approved the project in February 2022. The voltage increase must be carried out on the existing pylons and route. This decision is currently the subject of proceedings before the Federal Administrative Court

As part of the measures for security of supply in the winter of 2022/2023, the Federal Council provided information on the option of a temporary voltage increase on the Bickigen - Chippis extra-high voltage lines. The measure is only planned for the period January - April 2023. From a technical point of view, Swissgrid is preparing to operate the Bickigen - Chippis line temporarily at 380 kV in the event of a critical supply situation.

The commissioning of this line is preceded by more than 30 years of history. It is the oldest extra-high voltage line project in Switzerland. Why did it take so long from the initial idea to realization?

Projects to build extra-high voltage lines take time. On average, 15 years pass between the start of a project and its commissioning. The Chamoson - Chippis project is breaking all records with 36 years. Most of this time was spent on studies, planning, approval procedures and, in particular, legal proceedings. Objections to the project were raised several times and had to be judged by the Federal Administrative Court and the Federal Supreme Court

In contrast to the studies and procedures, the construction of the pipeline took only four years.

The old pipelines are now being dismantled. In what time horizon?

The bundling of four different voltages on one route makes it possible to dismantle 90 kilometers of overhead lines and 322 pylons in the Rhone plain. The dismantling of these lines will begin in 2023 and, according to current planning, will be completed in 2027.

Where are other bottlenecks in the Swiss transmission network?

In its "Strategic Grid 2025", Swissgrid has defined all the grid projects that are essential for a secure and reliable Swiss transmission grid. Some of them are blocked in their implementation by objections. In addition to the two projects Bickigen - Chippis and Chippis - Mörel in the Valais, these include the Airolo (TI) - Lavorgo (TI) and Niederwil (AG) - Obfelden (ZH) grid construction project. The Pradella (GR) - la Punt (GR), Bassecourt (JU) - Mühleberg (BE) grid construction projects and the Mörel - Ulrichen line in Valais are currently under construction

The approval processes for grid development and expansion and for new production facilities take too long. There is major resistance to almost every project, even after the sectoral plan and plan approval processes have been legally concluded. For Swissgrid, it is therefore central that the processes for grid construction projects are accelerated

The Swiss transmission grid:

Swissgrid is the owner of the Swiss transmission grid. Its network, which is over 6700 kilometers long, transports electrical energy at 380 and 220 kilovolt voltages. In addition to all the lines, the transmission network includes 147 switching stations.

Swissgrid ensures that the grid is always available through regular maintenance, renewal and expansion in line with demand. Swissgrid is investing 2.5 billion Swiss francs in this by 2025. Swissgrid thus forms the backbone for a secure power supply.

The path of electricity from the producers to the socket is long and sometimes complex. The electricity passes through various levels until it is finally transformed to 230 volts and can supply coffee machines, cell phones or refrigerators with electricity.

The transformation is one challenge. Having the right amount of electricity in the grid is another. And always as much electricity as is needed at any given time. Energy consumption and energy production must always be in balance. Swissgrid takes care of this. Around the clock. Seven days a week.

Source: Swissgrid

Interview and text: Brigitte Mader, Communications, Swiss Federal Office of Energy