Comparison with an underground cable solution
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.
Project changes: Replacement rather than reinforcement of 50 pylons
During the preparations for the construction work, Swissgrid checked the pylon statics and determined that some pylons were too weak for the planned expansion of the route to two 380 kV lines. Based on these findings, Swissgrid decided to replace 50 pylons instead of reinforcing them. This change to the project will not result in any changes to the route. As a result, the commissioning of the upgraded line will be delayed by at least one year and is now scheduled for 2022. The project amendment was published by the municipalities between 19 September and 21 October 2019. The Federal Inspectorate for Heavy Current Installations (ESTI) issued the construction permit for this project change on 7 July 2020.
Project progress and project planning
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 involves reinforcing or replacing the pylons where necessary. Swissgrid is planning to undertake the first stage of the construction work (from Zernez to La Punt) in 2021, and the second stage (from Pradella to Zernez) will follow in 2022. All pylons will receive a green protective coating. The grid project is expected to be completed by the end of 2022.