Centrale hydroélectrique de la Meije – Saint-Gobain PAM

Centrale hydroélectrique de la Meije – Saint-Gobain PAM


This project is a project of
Hydroelectric Power Plant we’ve developed since June 2013.
So this site has been selected because it’s a very poor site in
fish farming and has a high degree of hydraulicity since Romanche is
a fairly important watercourse who allows equipment of this kind.
For a year we developed the technical details of the different phases of the
jobsite and this one started in the beginning of May 2017.
It will continue until the arrival of winter and it will resume next
year in the spring to finish we think around September or
October 2018 and the goal is to start the installation early 2019.
There were access roads, there was a track that existed, it avoided to
make large earthworks infrastructure so the conjunction of
a major hydraulic interest, a reduced biodiversity and especially its access tracks
have made that the site was interesting and above all, there was a political will
of elected members to receive this type of installation on their commune. They are
quite promoters of green energy, especially hydropower.
Hydropower for our countries is the energy of the future. Those who have wind
put wind turbines, we have the water, the slope,
it makes sense that hydropower becomes renewable and clean
energy on our countries. Projects like this micro-power plant in our
budget is something important because it will help us a lot
to make a number of improvement investments. Really it was a
pleasure to work with Hydrowatt. The constraints of the development of this
project was to have environmental constraints since we are in a
site that is quite majestic and protected. We are on the edge of the Ecrins National Park and then we have a river
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so we must still preserve the environment. For that, we chose to use a
track and existing ways to pass the pipe. There are very large
diameter pipe on a great length. At first it was necessary to
convince the authorities that the environmental impacts were reduced and largely
compensated, then the second phase was to develop the technique for the
installation of all these works and all these sets. The difficulty of this jobsite is with
the environment because we have a fairly small footprint.
The material used, ductile iron is ideal for cet environnement
this environment as we do not need
welding we just fit the pipes between them. A socket fitted with
standard gasket connected to spigots allow
angular deviation which give us a well formed anaconda. Then, we
can have soil movements the pipeline will not suffer of any
consequences: that’s the strength of ductile iron. Here, the difficulties were
mainly related to the large size of the works. There are 4km and
200 meters of pipes to lay with imposing diameters, wich are 1m60
for half and then 1m40. So we had to have
axes of passage, ways. This penstock is composed of 2000 meters
of DN1600 pipe and 2000 meters of DN1400 pipe,
ductile iron pipes which represents 500 pipes. 500 pipes that could represent
500 trucks and Saint-Gobain PAM has opted for telescoping:
So a DN1400 pipe fitted into a DN 1600 pipe. This allowed us
to reduce the transport to 250 trucks. For the environment it’s a pretty
big impact. The length of the DN1600 pipes is 8 meters 25, for 7 tons 55.
Here we are on the DN1400 trench we lay 6 to 7 pipes per day.
So here we are on the jobsite of the water intake. Since the works will be
completed over two years, we preferred this first year, to do all the
earthworks and ensure the deviation of the Romanche river, like that
next year when we arrive to restart the civil works

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there has been a long observation period on the soil stability
and on the deviation capacity to assume all flows.
The earthworks were made at the almost definitive coast and then the river.
was deflected for eight days [Musique] [Musique]
[Applaudissements] [Musique]
At the front we have a digger bucket of 50 tons. The complexity is that you can not
park, the trucks have to wait.
There are long reversing to do, juggling between trees and
pipes. [Musique] All the gravel is riddled, crushed because it’s
big rocks. Everything we riddle and crush goes to the back
to close the pipe. [Musique] So then, still at the back, we need
to deposit a wastewater network. On this site we currently
building the power plant, the electric production plant of all this project.
The biggest specificity is the height, it’s quite special because
we will go up of one and a half panels more compared
to what we can see right now. This building will rise to more than 10 meters
high. The installed electrical power
is 3.6 megawatts. We will produce about 12 million kWh.
It’s a project who involves a very complete technicality and is one of the biggest
projects that the company has built and which also brings a lot of technicality.
Our team are very glad, we did a rewarding job, due to
all this techniques and skills multiplicity. It’s a very global project
that we built from A to Z at Hydrowatt. So this plant is planned
to operate in complete autonomy. It’s fully automatic, it
starts and stops by itself depending on the water level available at the
water intake. In case of a problem, it also stops by itself and in
these cases warns the person in charge of the operation. The operation
will take place with a team based in Ubaye and a guard on site who is
there to respond to everyday events.
Then all the preventive and curative maintenance part will be carried out
by the team located in Ubaye. In terms of automation
all the studies are performed in-house and we will say the heart of
the system, the PLC program that manages all startups and shutdown of the plant,
the regulation, the setting protection, etc … Have been done
and developed at our place. It’s a power plant that is close to the water so
it’s operating whatever the flow.
There is a risk of low production during the months of February and March, and
at September low water but it is supposed to work all year long.
It is a power station at the cutting edge of technology with all the innovations
of the moment. It is clear that nothing can be built in the Ecrins Park and that
we have been forced to be situated outside of the park. Site monitoring was very very very
sharp about the environment to avoid fauna or flora effects,
for example. So we had employees from Ecrins Park that came to
control us permanently. It was something that had to be integrated into the
design and the construction process. [Musique] le [Musique] On August 6 around 5 pm a
major disaster happened on the site. A huge thunderstorm that has fallen on the
top of the Tabuchet Glacier and created what is called a
torrential lava. So it’s a wave of important materials
, approximately 10 meters height who fell on the jobsite.
Between ten and fifteen thousand cubic meters of material estimated, who
went down and has completely buried the jobsite and the earthworks,
and the river took back its rights. There was no major material damage
to the structure that was under construction,
but it took four weeks with heavy earthmoving to
clear and then return to the originally earthwork
to continue the jobsite. The first things we did was
to check if the structure already built could resist to this
impact: it was the case so we did not have to strengthen it.
On the other hand, we made some adjustments in terms of monitoring
of operation, electro-mechanical and regulation to try
to guard if it’s happens again,
to avoid too much damage on the mechanical and
moving parts. The jobsite lasted for a total of 11 months.
It’s a project that cost 11 million euros, completely funded by our
Unit company and that will generate about one million euros of
turnover of electricity sales per year. [Musique] [Musique] The problem of the melting glacier and
climate changes is a real real concern for our job
The glacier has a virtue it plays a little role of sponge and stock.
It’s prevents the water that falls on the glacier doesn’t fall into the valleys
quickly. Now it’s clear that it loses about 2 m per year: there are

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sixty meters of ice so it’s mean that in 30 or 35 years the specialists
agree that we will have no more glacier and it’s going to be a problem. If I had to summarize this project I
think it’s an extraordinary human adventure because there is
a lot of technicality, there were big ressources.
It’s true that the frame may seem enchanting but it is
still very very difficult. We had to deal with a lot of problems and with some
biggest disasters on the jobsite but every time all the
companies played the gamed and helped us. I believe that a confidence
climate has been created, and it’s a real team success. We must thank all the people who intervened because they did a sensational job.

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