Overview

The increase in voltage of the extra-high-voltage line between Chippis and Mörel from 220 to 380 kilovolts is part of the «Strategic Grid 2025» of Swissgrid. It is used to transport energy generated by hydropower in Valais to the urban areas of the Central Switzerland. This is an important element of the Energy Strategy 2050 and will increase the security of supply in Valais and all of Switzerland in the long term.

The project calls for the construction of a new approx. 44-km 380-kV line between the substations Chippis and Mörel. The Federal Council identified the corridor for the overhead line in the sectoral plan in 2012. The existing 220-kV line between Chippis and Mörel will be dismantled once the new overhead line has been commissioned. This step will provide relief to residential areas, especially around Leuk-Susten, Niedergampel, Gampel, Raron, Steg, Baltschieder and Brig.

Chippis – Mörel underground cable study

Swissgrid has updated the underground cable study for the Chippis – Mörel grid project on various sections between Agarn and Mörel on behalf of the authorities. Swissgrid has also prepared a study to re-examine the line routing through the Pfynwald national protection reserve. Possible design options for an underground line between Agarn and Chippis have been examined in detail, e.g. mining the solid rock south of the Pfynwald to place the cabling behind the scree or bundling the project with the A9 motorway tunnel in the Pfynwald. The authorities now have the basis for deciding whether and where to build an underground cable or an overhead line.

Improvement compared to the current situation

• The new 380-kV line runs away from the settlement areas along the shady south-facing slope. The existing 220-kV line leads right through a number of villages in the area of Leuk-Susten, Niedergampel, Gampel, Steg, Raron Baltschieder and Brig, restricting them in their development.
• The cable study conducted in Pfynwald forest concluded that an underground line does not constitute an added value for this natural landscape. Swissgrid is implementing various replacement and environmental protection measures to compensate for the intrusion into nature. The two extra-high-voltage lines Chippis – Mörel and Chippis – Stalden run parallel between the substation Chippis and Agarn. In addition, Swissgrid is cabling various lines on a lower-voltage level (for example the 65-kV line Leuk – Lötschen) or bundling them on the new route (for example the 65-kV line Chippis – Turtmann). Overall, the burden on this unique pine forest will be reduced in comparison to the current situation.
• The removal of the 65-kV overhead lines will especially provide relief to the industrial area of the municipality of Salgesch as well as the residential areas in Leuk-Susten and Agarn.
• The burden on the population will be reduced overall by the greater distance of the line to the residential areas. Electromagnetic fields will either meet or be well below the limits defined in new and strict regulations.

Project

The project calls for the construction of a new 44-km 380-kV extra-high-voltage line between the substations Chippis and Mörel. The new line route will pass along the shady southern-facing slope. An additional 220-kV circuit (Stalden – Mörel) is planned to run from Visp to Mörel. Furthermore, the 220-kV line Mörel – Pallanzeno (Simplon line) will be laid on the route as of Ried-Brig to Mörel. The existing 220-kV line between Chippis and Mörel will be dismantled once the new overhead line has been commissioned. This step will provide relief to residential areas, especially around Leuk-Susten, Niedergampel, Gampel, Raron, Steg, Baltschieder and Brig.

In Visp, the new line will pass along the west-facing slope, in the south and along the east-facing slope around the village. Due to the steep hillside situation, the new line passes far above the village. The existing 220/65-kV lines Visp – Stalden already pass along the east-facing slope. These lines will be bundled with the 380-kV project. The current valley traverse in Eyholz via Lonza-Werke will be dismantled to the splitter mast in Lalden. In the area Unterstalden/Staldbach in Visperterminen, Swissgrid will lay the existing 220-kV line Stalden – Mörel as well as the 65-kV lines. This step will provide relief to the residential area «Untere Stalden».

For the natural protection reserve Pfynwald, the Swiss Federal Office of Energy (SFOE) has decided to lay the two extra-high-voltage lines Chippis – Mörel and Chippis – Stalden parallel between the substation Chippis and Agarn. This is for reasons of operational management, maintenance and repair in the event of failure. Swissgrid is cabling various lines on a lower voltage level (for example 65-kV line Leuk – Lötschen) or is bundling them on the new route (for example 65-kV line Leuk – Turtmann). Overall, the burden on this unique pine forest will be reduced compared to the current situation.

The project also includes approval for the 220-kV line Chippis – Stalden (Törbel line). This line currently only carries one power circuit and will now be supplemented with another. On the section from Chippis to the traverse of Emsbach in Agarn, the line will be constructed parallel to the new line Chippis – Mörel. The line route between Agarn and Stalden will remain unchanged.

The total cost for the new extra-high-voltage line Chippis – Mörel will amount to approximately 110 million Swiss francs.

Timetable

The project Chippis – Mörel was included in the sectoral plan for transmission lines (SÜL) in 2001. The Federal Council specified an overhead line corridor in 2012. Swissgrid was commissioned to construct the overhead line. On 29 March 2019, Swissgrid submitted the planning approval procedure for the 380-kV line project Chippis – Mörel and for the 220-kV line project Chippis – Stalden to the Federal Inspectorate for Heavy Current Installations (ESTI).

Ideally, the commissioning for the new 380-kV line Chippis – Mörel is planned for 2028. In case of objections and legal proceedings, commissioning may be delayed by several years.

Schedule in the best case scenario

Agarn – Mörel cable study

For each grid project, Swissgrid checks cable as well as overhead line options. Swissgrid conducted a study for laying the line underground (in German) in cooperation with a Valais-based engineering office on the Agarn – Mörel section to prepare for the grid project Chippis – Mörel. Regional development, the environment and economic efficiency are factors which are taken into consideration in addition to technical aspects.

Swissgrid proceeded as follows:

1. Swissgrid reviewed whether any significant changes took place in the decision-making foundations. This could include newly protected areas or infrastructure previously not taken into consideration which would enable a better cable line, for example an abandoned tunnel or old railway tracks. The cable study found that the situation in terms of the environment, regional planning, technology and costs has not changed much over the last few years.
2. Swissgrid analysed whether today’s state of technology for construction and cabling systems allows for a next generation of underground cable. Developments that would make the construction and operation of cable lines easier have not taken place in construction technology or in cable technology. Specifically, Swissgrid examined the possibility of underground lines at various sections near the overhead line corridor. Underground cables could be laid for a few individual sections. It is important to note that cable cannot be laid underground along the overhead line corridor.
3. Swissgrid reviewed the cost of possible underground line options in comparison with the cost of an overhead line option. The cost for the construction of a cable line depend on the terrain and substrate as well as the resulting structural shape. Energy prices have significantly dropped compared to back then which reduces the life cycle cost of a cable line. The cost for the underground line option were estimated to amount to about 13 million Swiss francs per kilometre in the cable study Agarn – Mörel. This is about 5 times as much as the overhead line for the same section.

The cable study reviewed nine subsections in the vicinity of the overhead line corridor. Thus, underground cables are only possible in some sections. To this end, transition structures would be required to connect the underground cable with the overhead line. They would be approximately the same size as an ice hockey rink and about 25 metres high. Underground line construction would be very complex and cost-intensive as some of the cable lines would pass through very steep terrain which is difficult to access. Furthermore, the lines would have to be laid under several bodies of water. As a result, these difficult terrain conditions would require the construction of four mining tunnels with a total length of approximately 8 kilometres.

The idea of laying underground cabling in the Pfynwald forest area between Agarn and Chippis had already been examined in 2012 as part of the sectoral plan procedure. This study concluded that an underground line would not constitute an added value for this natural landscape. Swissgrid is implementing various replacement and environmental protection measures to compensate for the intrusion into nature. The two extra-high-voltage lines (Chippis – Mörel and Chippis – Stalden) run parallel between the Chippis substation and Agarn. In addition, Swissgrid is cabling various lines on a lower-voltage level (for example the 65-kV Leuk – Lötschen line) or bundling them on the new route (for example the 65-kV Chippis – Turtmann line). Overall, the burden on this unique pine forest will be reduced in comparison to the current situation.

Swissgrid has updated the underground cable study for the Chippis – Mörel grid project on various sections between Agarn and Mörel on behalf of the authorities. Swissgrid has also prepared a study to re-examine the line routing through the Pfynwald national protection reserve. Possible design options for an underground line between Agarn and Chippis have been examined in detail, e.g. mining the solid rock south of the Pfynwald to place the cabling behind the scree or bundling the project with the A9 motorway tunnel in the Pfynwald.