Connection Nant de Drance

Several 380 kilovolt overhead lines and underground cables between Nant de Drance and the Rhone plain near Martigny are required to connect the Nant de Drance pumped storage power plant. Without these connections, the energy of around 1 gigawatt cannot be fully transported

Your contact for this grid project

André Räss
André Räss

Phone +41 58 580 21 11
info@swissgrid.ch

380 kV line
380 kV line
380 kV underground cabling
380 kV underground cabling
220 kV line
220 kV line
220 kV underground cabling
220 kV underground cabling
SBB line
SBB line
SBB underground cabling
SBB underground cabling
Dismantling
Dismantling
Existing line
Existing line
Substation
Substation

Overview

As part of this project, the Nant de Drance pumped storage power plant was connected to the extra-high-voltage grid. Connection to the power plant entails three projects:

Le Verney – La Bâtiaz

Construction of a new 2 x 380 kV cable line to replace the existing 220 kV line that runs through the Rhone Valley for a distance of 1.2 km. In operation since 1 April 2022.

La Bâtiaz – Châtelard

Construction of a new 12.5 km 2 x 380 kV line to replace the 220 kV line. In operation since 2018.

Châtelard – Nant de Drance

Construction of a new 6.5 km 2 x 380 kV cable line in the cave in order to connect the power plant at Nant de Drance with the Châtelard substation. In operation since 2018.

Substations

The project consists of three substations: the substation at Nant de Drance (380 kV) located in the cave, the substation at Châtelard equipped with a 380/220 kV transformer, and the substation at La Bâtiaz equipped with 380 kV installations. These three substations have been in operation since 2018.

Animation of the pumped-storage power plant at Nant de Drance
1/29: Construction Nant de Drance June / July 2015
2/29: Construction Nant de Drance June / July 2015
3/29: Construction Nant de Drance September 2015
4/29: Construction Nant de Drance October 2015
5/29: Construction Nant de Drance October 2015
6/29: Construction Nant de Drance October 2015
7/29: Construction Nant de Drance October 2015
8/29: Construction Nant de Drance January 2016
9/29: Production of the pylons February 2016
10/29: Construction Nant de Drance March 2016
11/29: Construction Nant de Drance April 2016
12/29: Construction Nant de Drance May 2016
13/29: Construction Nant de Drance May 2016
14/29: Construction Nant de Drance May 2016
15/29: Gas-insulated switching substation May 2016
16/29: Construction Nant de Drance July 2016
17/29: Construction Nant de Drance April 2017
18/29: Construction Nant de Drance April 2017
19/29: Construction Nant de Drance April 2017
20/29: Construction Nant de Drance May 2017
21/29: Construction Nant de Drance June 2017
22/29: Construction Nant de Drance May 2018
23/29: Construction Nant de Drance May 2018
24/29: Construction Nant de Drance September 2018
Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
25/29: Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
26/29: Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
27/29: Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
28/29: Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020
29/29: Begin of the construction of the 380 kV cable line between La Bâtiaz and Le Verney, July 2020

Project

Project update

The Nant de Drance pumped storage power plant connection project involves the construction of several 380 kV overhead and underground lines between Nant de Drance and Martigny in the Rhône valley, Swiss Federal Railways (SBB) 132 kV power lines between Châtelard and Vernayaz, and 220 kV lines between Châtelard and Vallorcine. All these installations are now in operation and the old 132/220 kV Le Châtelard – La Bâtiaz overhead line was dismantled in 2019.

132 kV Le Châtelard – Vernayaz SBB line

The new SBB line is part of the Swissgrid project for the construction of the extra-high-voltage line that connects the Nant de Drance power plant to the electricity transmission grid. The new line will be overhead from Le Trétien to Les Combasses, then underground from Les Combasses to Vernayaz. Construction work began in July 2022. The cabling of the new SBB line from Les Combasses to Vernayaz and the dismantling of the existing overhead SBB line are part of the compensatory measures linked to the construction of the new Le Châtelard – La Bâtiaz extra-high-voltage overhead line. It should be noted that no work will be carried out on the Le Châtelard – Le Trétien section. This overhead section of the Le Châtelard – Vernayaz SBB line will remain unchanged.

Construction work on the new Le Châtelard – Vernayaz SBB line started in July 2022. The project is expected to be completed by the end of 2024 with the dismantling of the existing SBB overhead line.

General site plan Nant de Drance
General site plan Nant de Drance

Interviews of project stakeholders

Representatives of the main parties involved in the project to connect the Nant de Drance power plant give their views on the subject:

1/5: Eric Wuilloud, Director of the Nant de Drance power plant
2/5: Anne-Laure Couchepin Vouilloz, Mayor of Martigny
3/5: Florian Piasenta, Mayor of Salvan
4/5: Pascal May, Mayor of Finhaut
5/5: Eric Wuilloud, Director of the Nant de Drance power plant

People & environment

Landscape

The new 380 kV Châtelard – La Bâtiaz overhead line has been constructed in the Gorges du Trient at an altitude of 800 metres at the edge of the forest. It was brought into service in 2018, enabling the dismantling of the old 220 kV overhead line crossing the village of Salvan. Following the planned dismantling of the old 132 kV SBB overhead line, there will no longer be any overhead electrical line on the Salvan plateau, as the new SBB line will be buried from the lower part of Les Marécottes until Marcot.

The burying of the La Bâtiaz – Le Verney 1.3 km section will eventually enable the dismantling of the old line crossing the Rhone Valley between La Bâtiaz and Le Rosel.

Biodiversity

Revitalisation of dry grassland of high natural value in the Salvan municipality. This revitalisation encourages the proliferation of rare or endangered species of flowers.

Biotope

Creation of ponds in the Salvan municipality to encourage the development of amphibians such as the European common frog, common toad and Alpine newt.

Electromagnetic fields

The burden on the population will be reduced by the greater distance of the line to the settlements. The limit of 1 μT for electromagnetic radiation will be complied with across the board, with some areas reporting values well below this limit. The noise burden will be significantly reduced thanks to the use of the latest technologies and triple conductors.


Downloads


Videos of the construction

3D infographic of the mini tunnel boring machine
Drilling of the tunnel is completed
1/7: Connection Nant de Drance
2/7: La Bâtiaz – Le Verney
3/7: 380 kV cable line Nant de Drance – Châtelard
4/7: Transport of the 380/220 kV transformer to Châtelard
3D infographic of the mini tunnel boring machine
5/7: 3D infographic of the mini tunnel boring machine
Drilling of the tunnel is completed
6/7: Drilling of the tunnel is completed
7/7: Photos of the 380 kV cable line La Bâtiaz – Le Verney

Project news

  • | Media release

    La Bâtiaz – Le Verney underground cable link

    Read article
  • The baptism of the mini-tunneller
    | Blog

    An extra-high-voltage line delivered ready for use

    Read article
  • The operator controls from the window
    | Blog

    La Bâtiaz – Le Verney: divers to the rescue

    Read article

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