Visit to the hydroelectric power station Grand'Maison

 by Michèle Garlaschelli, Marie Pierre Jardillier, Robert Jacquemoud.

A handful of curious students who also have English lessons with our teacher Melanie Brumberg, decided to extend their scientific knowledge of the production of electricity, (a green and clean energy).

What would we do today without electricity?

Actually, very few things.

We live in a region where this industry was born. It was invented in Grenoble in 1869 by the French engineer Aristide Bergès.

We are lucky to have the most powerful hydroelectric development in Europe near Grenoble. It is located in the Eau d’Olle valley in the cities of Vaujany and Allemond.

Nothing could be easier than spending the day in this magnificent mountain district “Les Grandes Rousses”.

There we visited the EDF Hydrélec Museum which adjoins the Grand’Maison hydroelectric power station. There, the different stages, show the development of electricity from its discovery by Volta to the present day.

After a lunch at the “V” restaurant in Vaujany ski resort, we visited the Grand’Maison hydroelectric power station.

 Figure 1 Verney reservoir 

GRAND’MAISON

On 12 October, we went to Grand'Maison, the most powerful hydroelectric power station in Europe. We met Robert who organized the museum visit, the lunch and the power station visit with his son.

It was great! 

Two dams for a Pumped Energy Transfer Station (PETS)

The water in the upper Grand'Maison reservoir is turbined by the downstream power station to produce electricity and then stored in the lower Verney basin.

It is pumped back up at times when the demand for energy is lower

The Grand'Maison dam is located at 1700m.

The Verney is located at 770m.

Both are 'gravity' dams made of earth and rocks.

                                   Grand'Maison                                

Grand'Maison dam is 550m long, 140m high, it can store 140 million m3 of water. The power station is located 900m below, it is made of 2 plants with 12 generating units: external plant with 4 pelton turbine underground plant, 70m below, with 8 « reversible » units (turbine and pump).

 The Verney dam is 430m long, 42m high, its reservoir has 14 million m3.

In just 3 minutes, Grand'Maison can produce a power of 1,800 MW, the equivalent of two nuclear units.

Figure 2  High voltage substation (400kV)

Figure 3    Reversible engine room (turbine or pump)

Figure 5     Ball valves / underground power station

 EDF HYDRELEC MUSEUM 

In the Morning we visited the EDF Hydrélec Museum. Very interesting with many interactive animations, educational modules, and multimedia devices.

All is very accessible and there are visits organized with schools to show the children how electricity is produced.

They were many pictures and history about the beginning of industrialization since the 19th century.

The museum presents a collection of 450 instruments used since the 19th century.

They were also small machines we could test which showed how to produce electricity with solar energy for example.

There was also a model of a hydroelectric power station showing the way of the water between the two dams, Verney and Grand’ Maison, and how electricity is produced and transported to be used in each house!

In the basement, there is a room where old hydroelectric turbines of all types are presented.

A video shows the speed and strength of the water in the river when the dam opens the floodgates and release water.

The river presents an apparent calm and suddenly, in less than 5 minutes the level reaches 2 meters high.

so it’s very dangerous to bathe or stay on the edge of the river because we never know when the floodgate will open.

 

RESTAURANT LE “V” VAUJANY 

We leave The EDF Hydrélec Muséum with regret, there are still so many things to discover. It’s time for lunch. We have to go up to the village of Vaujany located about 7 km away (1250 m above the sea level). We are expected at the “V” restaurant (“V“for Vaujany).

We are happy to discover a village that is a little sleepy. The excitement of the summer period is over and the winter one has not yet begun. From the terrace of the restaurant the view of the valleys below, of the Eau d’Olle and Romanche is magnificent.

It’s time to sit down to eat, the day is not over yet! We are greeted by a  lovely staff. Over a gastronomic meal the exchanges are going well. The atmosphere is friendly and warm.

The last sip of coffee swallowed, we must remember to go back down to the valley on the banks of the Eau d’Olle in order to continue the technical visit of the Grand’Maison Hydroelectric power station. And now it’s time for active pedagogy with our guide!