On 23 October, the symbolic ground-breaking ceremony for the expansion of the strategically important Pradella – La Punt extra-high-voltage line was held in Zernez. Swissgrid is expanding the existing line, thereby removing a grid bottleneck.
The 49-kilometre extra-high-voltage line between Pradella and La Punt is currently a bottleneck in the Swiss and European transmission grid. To remedy this, a second circuit with a capacity of 380 kilovolts (kV) is being added to the line. At the same time, the Pradella substation is being modernised.
The grid expansion is a Strategic Network 2025 project. The expansion will strengthen the connection with the European integrated network – with Austria and Italy – and will secure the transport of the energy generated by hydropower in Grisons. Eliminating the bottleneck will increase grid stability and transport capacities and also the security of supply in Switzerland and Europe. In addition, it will ensure that Engadin has a reliable power supply if the local electricity production is disrupted.
Construction work in stages
Civil engineering works have been in progress since the summer of 2017. The ground-breaking ceremony took place today in the presence of representatives from Swissgrid, Engadiner Kraftwerke AG (EKW), Axpo and all affected municipalities. The construction and assembly work will take place in stages between the end of April and November. The expanded line will be put into operation in the autumn of 2021. The removal of the overhead lines between Pradella and Zernez, which are used to supply power to the valley at lower voltage levels, will start in 2022. The expanded, gas-insulated 380 kV switching substation in the Pradella substation is to be connected to the grid in 2020. The existing 220 kV outdoor substation will be dismantled.
Easing the burden on the population and the environment
As part of the expansion of the Pradella – La Punt extra-high-voltage line, Engadiner Kraftwerke AG (EKW) will dismantle the existing 60 kV overhead lines and ensure the valley's power supply via an underground 110 kV cable line. Some 1,000 wooden poles and small pylons will be dismantled, which will reduce the impact of pollution on both the environment and the population in the long term. The dismantling will also have a positive impact on the landscape. Swissgrid is assuming a significant portion of the costs and thus fulfilling the stipulation in the planning permit for the implementation of ecological alternative measures.