Eastern-Central Europe Scout Group Meeting

Field trip brochure prepared by Alex Muller, SPE Swiss section, © 2014
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SPE Swiss section
Thursday, 18 September 2014
FIELD TRIP PROGRAMME
07:45 Meeting in the main lobby of the Geneva Cornavin railway station.
08:03-09:40 CFF train departure “voie 4” from Geneva to Martigny
09:43-10:16 Train from Martigny to Finhaut
10:20-11:15 Presentation of the new Emosson “Nant de Drance” dam project
by former Emosson SA director Mr J.-M. Rouiller
11:18-11:38 Postal bus from Finhaut to Lac d’Emosson
11:45-12:30 Second part of Emosson dam presentation on site
12:45-14:00 Lunch at the Lac d’Emosson restaurant
14:00-15:30 Walk along the Emosson dam with geological regional overview
15:38-15:58 Postal bus from Emosson to Finhaut
15:59-16:35 Train from Finhaut to Martigny
16:48-18:27 Train from Martigny to Geneva
See map overleaf.
Many thanks to our sponsors for this outing:

Field trip brochure prepared by Alex Muller, SPE Swiss section, © 2014
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Itinerary map:
Swisstopo map 1:25’000 scale reduced  see page 5

Field trip brochure prepared by Alex Muller, SPE Swiss section, © 2014
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Dear SPE Swiss section members and Friends,
This year we will have the pleasure to meet for a special one day field trip in the western Alps, more precisely in
the Canton du Valais at the Emosson dam, related to hydraulic power generation and geology.
The Emosson area has a long history of hydraulic energy. The first dam named Barberine was built in the early
1920’s, in order to produce electric power to feed the train network of the Swiss Federal trains (CFF). Later on, a
second dam (Vieux Emosson lake) was built in the mid 1950’s at 2205 m altitude above the Barberine dam to
enhance water reserves of the lower dam by 13.5 million m3. The third Emosson dam was built between 1967
and 1973 and flooded the old dam. The current basin covers a much greater area and its reservoir was increased
from 40 to 227 million m3. Water from the reservoir first powers the 189 MW Vallorcine Power Station
downstream and just over the border in Châtelard, France. Water is then sent through a headrace tunnel to the
162 MW La Bâtiaz Power Station, 12 km (7 mi) to the east towards Martigny, Switzerland. The drop between the
dam and La Bâtiaz Power Station is 1,400 m (4,593 ft).
In 2009, Alpiq and the CFF launched an underground pumping/turbine project between the Vieux Emosson dam
and Emosson on the Nant de Drance. This project plans to pump water from the Emosson lake up to the Vieux
Emosson lake during low electrical consumption periods (nights and week-ends). This water will then be
turbined the reverse way at peak consumption periods.
Initially the project planned four turbines producing a total of 600 MW. The Forces Motrices Valaisannes then
took a 10% stake in the joint venture. The Alstom group is to furnish the variable turbines to be delivered by
2017. In December 2008 the works started and were planned to last for 7 years. In 2011, authorizations were
obtained to enhance power production from 600 to 900 MW. This involves increasing height of the Vieux
Emosson dam from 45 to 67 m. This modification brings the retained volume of water of Vieux Emosson from
13.5 to 25 million m3 with very little environmental impact.
The drilling of the galleries is now completed and the enhancement of the Vieux Emosson dam and all other
related works are currently underway.
During this field trip we will have a presentation of the entire Nant de Drance project on site by the consortium
engineers, see http://www.nant-de-drance.ch/accueil/. A lunch will be taken at the panoramic Emosson dam
restaurant (1970m) and in the afternoon we will walk along the dam with a geological overview of the area. The
famous Triassic dinosaurs’ tracks of Emosson, are too far to be reached on this trip (3 hours walk one way) and
may be the goal of a future excursion.
This field trip has been organised in order to travel by train and postal bus to reach the Emosson dam (see
detailed programme). The second train, a cog railway, the “Mont-Blanc Express”, from Martigny to Finhaut is a
very picturesque journey, worth the travel by itself!
I trust you will appreciate this unique visit to a very interesting power generation project underway in the Alps.
Yours sincerely,
Alexandre Muller
SPE Swiss section Chairman
September 2014

Field trip brochure prepared by Alex Muller, SPE Swiss section, © 2014
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Stop 1 Finhaut: Presentation of Nant de Drance new power generation project
by Mr Jean-Marie Rouiller, former Electricité d’Emosson SA
director
http://www.nant-de-drance.ch/accueil/ :
Stop 2 Emosson dam: Presentation of Emosson dams hydraulic power generation by
Mr Jean-Marie Rouiller, former Electricité d’Emosson SA
director
Stop 3 Emosson: Lunch at Restaurant du barrage d’Emosson
(Assiette Valaisanne & Raclette)
Stop 4 Emosson dam: Walk on the Emosson dam and regional geology introduction

Field trip brochure prepared by Alex Muller, SPE Swiss section, © 2014
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