Grid project Bickigen – Chippis

The energy from hydropower cannot be fully transported to the centres in Central Switzerland without expanding the existing lines. This requires an increase in voltage between the Chippis (VS) and Bickigen (BE) substations from the current 220 kilovolts to 380 kilovolts.

Your contact for this grid project

Sandra Bläuer
Sandra Bläuer

Phone +41 58 580 21 11
info@swissgrid.ch

380 kV line
380 kV line
Existing line
Existing line
Substation
Substation

Overview

The project provides for an increase in voltage along the 106 kilometre, 220 kilovolt line between the Bickigen (BE) and Chippis (VS) substations with a 380 kilovolt line. The 220 kilovolt line from Chippis to Bickigen was constructed between 1963 and 1965. The Federal Inspectorate for Heavy Current Installations (ESTI) had already approved this line for an operating voltage of 380 kilovolts, but to date it has only been operated at 220 kilovolts.

The transmission grid has structural bottlenecks in the Valais and in other regions and Swissgrid already regularly needs to instruct power plant operators to restrict production. To increase the capacity of the existing 220 kilovolt line between Chippis and Mörel, the entire line will be converted to a voltage of 380 kilovolts. Without connecting the transmission lines in the Valais to the 380 kilovolt grid, it will only be possible to transport around two thirds of the Valais production from hydropower once the new Nant de Drance pumped storage power plant commences operation.

To enable the full extent of the energy to be transported between the Chippis (VS) substation and the Bickigen (BE) substation, the entire line will be increased from the current voltage of 220 kilovolts to 380 kilovolts.


Temporary voltage increase on the Bickigen – Chippis line (Gemmi line)

The Federal Council has enacted various measures to strengthen security of supply in the short term. These measures are ready to be implemented in the coming winter in order to deal with extraordinary and critical situations. They include plans for temporary voltage increases on the Bickigen – Chippis (Gemmi line) and Bassecourt – Mühleberg transmission lines.

To prevent congestion in the transmission system in the coming winter, the Federal Council is allowing a temporary increase in the operating voltage of the two transmission lines between Bickigen and Chippis (Gemmi line) and Bassecourt and Mühleberg from 220 kilovolts (kV) to 380 kV in the period from January to April 2023. This will relieve congestion in the Swiss transmission grid so that the energy from the pumped storage power plants in the Alps can be transported in full to Central Switzerland. In an emergency, Swissgrid can increase the transfer capacity of the extra-high-voltage grid on the basis of criteria set by the federal government.

Test operation at a voltage of 380 kV

Swissgrid is making the necessary technical preparations to operate the Bickigen – Chippis and Bassecourt – Mühleberg lines at a voltage of 380 kV on a temporary basis in the event of a tense supply situation. The measure is only planned for the period between January and April 2023. Test operations will take place on both lines between mid-December 2022 and the end of February 2023. This will involve temporarily changing the voltage of the existing lines from 220 kV to 380 kV. The test operation with 380 kV will only be carried out if the grid situation allows it. The combined test operations will verify the lines from an operational point of view. The two voltage increases influence each other and can shift congestion depending on grid utilisation. The scope and duration of the test operations were approved by the Federal Inspectorate for Heavy Current Installations (ESTI).

Renovation work on the existing line

Swissgrid is making the necessary technical preparations to operate the existing Bickigen – Chippis 220 kV line at 380 kV on a temporary basis. Two 220 kV lines are currently connected via the electricity pylons along the Bickigen – Chippis route. For the temporary voltage increase, all phases will be shifted by one position so that the 220 kV line is on the lowest cantilever. The line systems on four electricity pylons in the vicinity of the Bickigen, Chippis and Wimmis substations have been transposed especially for this purpose. The line lead-ins to the Bickigen and Chippis substations have also been modified. This will minimise the impact on people and the environment as much as possible and ensure that the safety distances between the conductors and the ground, houses or cableways can be observed. The voltage change will slightly increase the noise level. The planned line modifications required for the permanent voltage conversion to 380 kV are currently in the approval process.

Transposing conductors

Two 220 kV lines are currently connected via the electricity pylons along the Bickigen – Chippis route. A line consists of three phases of alternating current that run one above the other on the three pylon cantilevers. The ground conductor runs at the top of the pylons and is for grounding, which means that it protects against direct lightning strikes. For the temporary voltage increase, the live conductors of the 380-kV line were transposed so that the 220-kV line is on the lowest cantilever. This will minimise the impact on people and the environment as much as possible and ensure that the safety distances between the conductors and the ground, houses or cableways can be observed.

Situation before the conductors were transposed
1/2: Situation before the conductors were transposed
Situation after the conductors were transposed
2/2: Situation after the conductors were transposed

Project

The line between Chippis and Bickigen is now to be operated on a voltage of 380 kV. It will be refurbished and modernised for this. The construction project is extensive: Changes are planned for more than 294 pylons. However the construction activities will be undertaken on the already existing pylons and lines. The original line route will therefore not be changed.

Before the line can be operated with 380 kV, it is mandatory that it be adapted to today's legislation – for instance stricter ordinances with regard to protection from noise or from non-ionising radiation. The voltage increase and modernisation activities contain among other things

  • an increase in the cable winch tension in order to increase the ground distance between the pylons (with 267 pylons),
  • the integration of double tension chains for the lowest derrick (for 50 pylons). That will increase the ground distance by around 4.5 metres in the area of the suspension pylons,
  • a heightening of the pylons by a few metres (30 pylons),
  • the integration of silent cables to reduce noise as well as
  • reinforcements to the foundations (for 245 pylons) and supporting structures (for 263 pylons).

The construction work will last a total of about two years. The construction period per pylon location will last between 3 and 15 days depending on the activity.


Facts and figures

Route lengthsChippis – Wimmis about 49,5 km
Wimmis – Bickigen about 57,1 km
Number of pylons297
Number of strands2
Number of bundles2
Electric conductors600 mm2 Aldrey
Voltage before / after220 kV / 380 kV
Amperage before / after1920 amperes / 1500 amperes

Milestones in the event of an optimal process

July 2015Planning approval dossier submitted to ESTI
November – December 2015Public circulation in the municipalities
February 2017ESTI sends the dossier to the Swiss Federal Office of Energy (SFOE). The SFOE then enters into conciliation negotiations with legitimate objectors.
February 2022The SFOE issues the planning approval decision and thus gives the green light for the voltage increase. Various appeals against this decision have been filed with the Federal Administrative Court. As a result, the project is expected to be delayed by another two years.
2027Commissioning

People & environment

Landscape

The construction project is extensive, but only has a minimal effect on the environment and landscape. Lasting environmental impact will occur in relation to the landscape, however the changes compared to the initial state will only be perceptible in the planned increase to the height of the pylons. The heights of 7 pylons will be raised between 2 and 6 metres, primarily in the Alpine region between Leukerbad and Kandersteg, but isolated pylon height increases will occur along the entire line. Targeted measures will minimise the negative impact on the soil, flora and fauna, and the initial state will be restored following the completion of the construction work.

Electromagnetic fields

The renovation work will reduce the magnetic field load along the entire line and significantly improve the current state. While operation at 380 kilovolts will increase noise emissions, the measures that have been introduced ensure that the emission limits are complied with across the board.

Restriction of operating current

Swissgrid always observes the statutory limits when constructing lines. The Ordinance on Protection from Non-Ionising Radiation (NISV) is always complied with. Swissgrid also reserves the right to operate the line at the previous intensity of current of 1920 amperes. This is based on the version of the NISV revised in July 2016. Increasing the voltage from 220 kilovolts to 380 kilovolts requires the heights of isolated pylons to be raised, certain foundations to be reinforced and the wire rope hoists to be tensioned in certain sections. These measures reduce the magnetic field without significantly restricting the operating current.


Downloads


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