The Pradella – La Punt line is essential for the transit of electricity and the security of supply in the canton of the Grisons. To enable the energy from hydropower to be transported in full, the route between Pradella and La Punt, which spans some 50 kilometres, had to be extended along its full length to two 380 kV lines. Swissgrid began construction in 2017. Commissioning of the upgraded line took place on 11 November 2022.
Electricity has been flowing along the upgraded extra-high-voltage line between Pradella and La Punt since 11 November 2022. This will eliminate a congestion point in the Swiss transmission grid. The Pradella – La Punt line is important for security of supply in the canton of the Grisons and in Switzerland as a whole. As an alternative measure for the project, 1,100 distribution system pylons have been dismantled in the Engadin.
Normally, a pylon is fitted with one line on each side. Between La Punt and Zernez, however, the pylons were only fitted with one line on one side prior to the project. The reason for this is that transport requirements were lower when the line was built in the 1960s. Swissgrid has now added a second 380 kV line to the entire 50 km route between Pradella and La Punt. Today, the pylons therefore carry one line on each side. This will have a positive effect on emissions as it will be possible to operate the line in such a way that the electric and magnetic fields of the two lines cancel each other out partially, thus reducing overall emissions.
| Length of line | 50 km |
| Lines | Two 380 kV lines |
| Number of pylons | 127 |
| Height of the pylons | Between 50 and 80 m |
| Steel for pylons | 5,005 tonnes |
| Number of screws | 260,000 |
| New conductors | 615 km |
| Green protective coating | 30 tonnes |
| Number of workers on the construction site | Up to 230 pylon assemblers and painters |
| Project costs incl. alternative measures | CHF 120 million |
Dismantling of 1,100 pylons due to the fact that the 110 kV line is being laid underground
As an alternative measure for the Pradella – La Punt grid project, Engadiner Kraftwerke (EKW) replaced the 60 kV overhead line between Pradella and Bever with an underground 110 kV line. This new line will be used to transport power from the Ova Spin power plant. The first section between Pradella and Zernez was put into operation in summer 2019. The second section between Zernez and Bever was completed at the end of 2019. The dismantling of the 1,100 pylons has significantly improved the natural scenery. The project has also enabled the cabling of the 16 kV line and the hook-up of the municipalities to broadband Internet.
The planned project approach was compared with the use of a new 380-kilovolt underground cable over the length of both the whole route and the four sections. The comparison was made in accordance with the assessment scheme for transmission lines set out by the Swiss Federal Office of Energy (SFOE). The comparison indicated that the additional costs for full or partial underground cabling were disproportionately high and only partially lessened the impact on the landscape.
The Pradella – La Punt project was launched in the 1990s with a preliminary environmental impact assessment (EIA) process. In January 2000, the planning work was suspended as a result of the impending market liberalisation, the delays in cross-border line construction projects and the requirements arising from the preliminary EIA process.
In 2007, the project work was restarted with the development of the detailed project and the report on the environmental impact. A year later, the SPTL check, based on the Sectoral Plan for Transmission Lines (SPTL), was carried out at the request of the Swiss Federal Office of Energy (SFOE), the responsible planning authority. In December 2008, the SFOE decreed that, on the basis of the SPTL check already carried out, it was not necessary to conduct an SPTL process. However, an EIA check did have to be carried out.
In 2009 and 2010, the planning submission and the report on the environmental impact were revised in accordance with the requirements of the SFOE. At the end of October 2010, the environmental impact assessment (EIA) report was submitted to the Federal Inspectorate for Heavy Current Installations (ESTI) for preliminary checking and approval of the specifications. In February 2011, a visual inspection took place with the cantonal and national authorities under the leadership of the Swiss Federal Office of the Environment (FOEN). The EIA was revised on the basis of this inspection.
In January 2012, information events took place in Zernez in order to provide information to the municipalities, environmental organisations, public and press. Between April 2012 and November 2013, the application documents were fundamentally revised in the light of the SFOE's new assessment scheme for transmission lines as well as various court judgements. Upon submission of the planning dossier to the Federal Inspectorate for Heavy Current Installations on 9 December 2013, the planning approval procedure (PAP) was initiated. In May 2016, the Federal Inspectorate for Heavy Current Installations gave its approval to the expansion of the 380-kilovolt line between Pradella and La Punt.
Swissgrid carried out the civil engineering work from 2017 to autumn 2019. During this time, the pylon foundations were reinforced and the concrete bases renovated at each pylon location. The next step involved reinforcing or replacing the pylons where necessary. Swissgrid planned to undertake the first stage of the construction work (from Zernez to La Punt) in 2021, and the second stage (from Pradella to Zernez) followed in 2022.
The project is not quite finished yet. In 2023, the pylons between Pradella and Zernez erected during the second construction stage will be given their definitive green coating. The pylons between Zernez and La Punt installed during the first construction stage had already received their green protective coating in summer 2022. Now the pylons fit much better into the landscape and are less visible. The coating on the pylons also protects against corrosion.
