Grid project Mörel – Ulrichen
New line between Ernen and Ulrichen in operation
The construction of the new 30-km-long extra-high voltage line in Goms is making great progress. On the section between Ernen and Ulrichen, electricity has been flowing since October 2019. However, the work is not quite finished yet. Only around half of the pylons have been painted green so far. The remaining pylons will be painted by summer 2020. As a result, they will fit in better with the surrounding landscape and will also be protected against corrosion.
In contrast, 177 pylons and conductors from the old overhead lines – the 220 kV Swissgrid line and the regional electricity grid operator Valgrid’s 65 kV line – will be dismantled from 2020. This will improve the appearance of the landscape and surrounding villages of Ernen, Ritzingen and Reckingen. The pylon foundations will also be removed to a depth of around 1 metre. The former pylon sites will be revegetated.
The dismantling and removal will benefit the surrounding villages and landscape.
Deforestation between Mörel-Filet and Ernen
Before construction of the extra-high voltage line can begin, the forest will need to be cleared at the pylon locations and at individual points along the future route of the lines. This work is likely to be finished after winter 2020/21. During this work, some of the wood will be removed with a mobile cable crane. This means numerous helicopter flights can be dispensed with, which in turn reduces noise emissions. Transportation by helicopter is generally indispensable on construction sites in alpine regions.
The construction of an extra-high voltage line impacts the landscape and the environment. During the construction phase, the new line is particularly visible, and it takes a few years for the trees and bushes to grow back in the cleared aisle. However, the forestry work is necessary to ensure safety on the construction site and safe operation of the line. At the pylon locations, an area of around 14 x 14 m is permanently cleared. A 30-metre-wide corridor also needs to be cleared along the route of the lines. In steep terrain, the area to be cleared can be larger. Along the route of the lines, small trees and bushes do grow back. This is referred to as suppression of plants and trees.
Trees and shrubs grow back again in the area that was cleared.
Safety for people and the environment
Once the forest area has been cleared, together with the specialist departments and engineering offices in the canton, Swissgrid checks whether safety measures are necessary to protect people and the environment. For example, snow barriers and timber tripods are often erected to protect against avalanches. Swissgrid also plants young trees in glades along the route of the lines. Such avalanche protection measures have already been successfully implemented in the communities of Ernen, Goms and Obergoms. One the one hand, they guarantee the safety of the roads, which are used all year round. On the other, they also support the growth of the forest near the line. These measures will be gradually put in place during the entire construction phase.
Swissgrid will start construction of the new extra-high voltage line on the section between Mörel-Filet and Ernen in 2021. The footpaths leading to the future pylon locations and installation areas will be created by the spring. Construction of the pylon foundations and assembly work is expected to begin in summer 2021. In steep or unstable terrain, the foundations will be anchored in the ground with metal rods and secured with additional measures. This line section is expected to be commissioned by the end of 2022. The dismantling of the current 220 kV Swissgrid line and the 65 kV Valgrid lines will take place in 2023.
Grid expansion in the Upper Valais region is not progressing everywhere
The extra-high voltage line between Mörel-Filet and Ulrichen, which is approximately 30 km long, continues to take shape. However, Swissgrid is not achieving the same progress everywhere as it is with the new line in Goms. The lines in the Upper Valais region are used to transport electricity produced from hydro power in Valais – for example, from the new pumped storage power plant in Nant de Drance. The grid project is an important element of «Strategic Grid 2025» and will serve Valais and the rest of Switzerland. To ensure electricity can flow without congestion, the voltage of various lines must be increased to 380 kilovolts. New transformers and substations must also be connected to the grid. This will make it possible to transmit electricity to the population centres in Central Switzerland using various connections, such as those in Gemmi, Grimsel or Nufenen. Until that happens, Swissgrid will still have to realise some other grid projects in the Upper Valais region.
The modernisation of the transmission grid in the Valais region serves to transport the electricity generated via hydro power in Valais.
Author
